F-22, stuff you should know

**Garry** · 19 Jan 06, 19:40

Originally Posted by Rusky

Unless you didn't notice, Russians are the REAL europeans. We have developed technologies the rest of the world would not have without us. The boosters we make (the ones NASA purchased) are 5 times as powerful as the best american ones yet of the same size. The concept of TAPAMAK (a way to magnetically confine plasma) was deemed impossible by all the Western scientists until Russians showed up with 3 working prototypes, now it will be used on nuclear fusion reactos of the future all over the world. We were the first to put a man into space, a woman, first space station, we havfe already developed the vaccine for the bird flu, US has purchased our technologies like mobile nuclear reactor back in 1994, those nations who used to buy from US only now purchases Russian equipment like BMP-3 for United Arab Emirates. We are not just on the same level with you, in some aspects we are superior. Russia a giant base of bright engineering heads, the second largest on earth actually, so while the rest of you less educated folk use insults, we use factual information in a constructive manner, which you still in the end deny.

You're just a redneck in denial. Not you and non of your buddies can put up a real argument against this article, the best you can do is throw insults and smilies, to make you seem like you know what you are talking about. If you do use FACTUAL information to refute, not some half-baked BS you dug up your ass.

And here we are again, a racist redneck does not want to part with his fantasy world and chooses to compensate by attempting to insult me. Grow up.

Some people are not good opponents to argue with. Blind minds. Imagine that you're are not blind and try to explain something to them? Waste of time. This forums are good only when you can learn something....

Lets admit. There are many people like this in many nations.... I live in Moscow now and morons are available here just like anywhere else.... I lived in NY and it is full of crazy people. I never bother giving them idea who they are whereeve meet them.

**Horrido** · 19 Jan 06, 20:50

Holster the insults, folks. All it does is waste people's time having to wade through the BS. Name-calling only demonstrates you don't have what it takes to either get your point across or support your position. Being offended is a choice, and I have a MUCH higher regard for thick-skinned individuals that can fight past the fire with discipline intact. Like I've been trying to get through to folks, post the data, cite the source, take a step back (think of it kinda like a legal case in court

). Otherwise, just accept the fact that you can lead a horse to water... and let the merry in-DUH-vidual continue on in ignorant bliss.

**Rusky** · 19 Jan 06, 21:10

Originally Posted by Garry

Lets admit. There are many people like this in many nations.... I live in Moscow now and morons are available here just like anywhere else.... I lived in NY and it is full of crazy people. I never bother giving them idea who they are whereeve meet them.

I see your point exactly, i also live in Moscow by the way. The thing is that proportion wise more morons in US have internet access.

**Defcon 6** · 19 Jan 06, 21:26

Originally Posted by Horrido

Holster the insults, folks. All it does is waste people's time having to wade through the BS. Name-calling only demonstrates you don't have what it takes to either get your point across or support your position. Being offended is a choice, and I have a MUCH higher regard for thick-skinned individuals that can fight past the fire with discipline intact. Like I've been trying to get through to folks, post the data, cite the source, take a step back (think of it kinda like a legal case in court

). Otherwise, just accept the fact that you can lead a horse to water... and let the merry in-DUH-vidual continue on in ignorant bliss.

Your right, it's about time I crushed Rooshoo and friends with facts and evidence.

Let this court commence-

The only thing I want to mention is that the F-22 is only two times the size of an F-16.

Unfortunately there is no point to make here since the F-16 flies with the reserve anyways. The F-22 is a replacement for the F-15, not the F-16. So right off the bat you don't understand what your talking about in this case.

The F-15 specifications are as follows-
Variant C/D models E/F models
Primary Function Tactical fighter. Tactical Bomber
Contractor Boeing (McDonnell Aircraft and Missiles Systems) Boeing (McDonnell Aircraft and Missiles Systems)
Power Plant Two Pratt & Whitney F100-PW-100 turbofan engines with afterburners, each rated at 25,000 pounds engine ( 11,250 kilograms) two Pratt and Whitney FIOO-P-220 turbofans each rated at 14,670 lb st (65.26 kN) dry and 23,830 lb st (106.0 kN) with afterburning or,
after August 1991, two FlOO-PW-229 each rated at 17,800 lb st (79.18 kN) dry and 29,100 lb st (129.45 kN) with afterburning;

Length 63 feet, 9 inches (19.43 meters). 63 ft 9 in (19.43 m)
Height 18 feet, 8 inches (5.69 meters). 18 ft 5.5 in (5.63 m)
Wingspan 42 feet, 10 inches (13.06 meters) 42ft 9.75 in (13.05 m)
Wing aspect ratio 3.01
Wing area 608.00 sq ft (56.48 m2)
Speed 1,875 mph (Mach 2.5-plus). 1,433 kt (1,650 mph; 2655 km/h) maximum level speed 'clean' at high altitude
495 kt (570 mph; 917 km/h) cruising speed at optimum altitude
Ceiling 65,000 feet (19,697 meters). 60,000 ft (18290 m);
Operating Empty Weight 31,700 lb (14379 kg)
Maximum Takeoff Weight 68,000 pounds (30,600 kilograms). 81,000 lb (36741 kg)
fuel 13,123 lb (5952 kg) internal
21,645 lb (9818 kg) in two CFTs
up to three 610-US gal (2309-liter~ drop tanks;
Range 3,450 miles (3,000 nautical miles) ferry range with conformal fuel tanks and three external fuel tanks. 3,100 nm (3,570 miles; 5745 km) ferry range with CFTs and drop tanks
2,400 nm (2,765 miles; 4445 km) with drop tanks
1,000 nm (1,150 mi; 1,853 km) Max Combat Radius
685 nm (790 miles; 1270 km) combat radius

So right away your entire theory melts since the F-15 is 63.9 feet long compared to the F-22's 62.1

The F-16 is not an air superiority fighter. Your arguement has been crushed.

Really? Stupidest statement you ever heard? You never read your own statements?

Rusky once again is wrong. Let me post a link to the insurmountable evidence.

http://www.globalsecurity.org/milita...laaf-intro.htm
http://www.globalsecurity.org/milita...hina/plaaf.htm
http://www.globalsecurity.org/milita...laaf-equip.htm

Yeah, your done. Go take a nap. China does indeed have the largest air force in terms of sheer numbers. China has some 4,000 fighter aircraft and 6,500 total aircraft. Making it the largest air force in the world.

**The_Burning_Kid** · 19 Jan 06, 21:31

Don't waste your times guys. This is the same person that can't say anything better than "your in denial" when he can't make a good counterargument. Its honestly funny. I wouldn't waste brainpower on someone like him.

**Defcon 6** · 19 Jan 06, 21:33

Furthermore, lets have a review of the F-22 and it's capabilities.

If building an aircraft that has been described as "the only thing more complex than the human body" in five separate geographic locations wasn't challenge enough, the F-22 team also has to build an aircraft to tolerances on the order of ten-thousandths of an inch in order to meet its stealth requirements. Certainly not an easy assignment.

But the initial hurdles have been overcome. When the first F-22's fuselage was mated in the fall of 1996, the pieces went together just as the designers had predicted they would. Final mate of the forward fuselage that was made in Marietta, Ga., to the mid fuselage made in Fort Worth, Texas, and that mid fuselage to the aft fuselage made in Seattle, Wash., took only a few days to accomplish. The first shipset of wings was mated in less than 48 hours. The vertical stabilizers went on in less than a day. Between the two body mates and the wing joins, a total of 40 shims had to be generated, all about the thickness of a sheet of paper.

The Integrated Product Team (IPT) philosophy that the F-22 and F119 are being developed under has paid big benefits in the manufacturing area. The IPT concept has moved manufacturing from its traditional place down the schedule to up front with the designers. Manufacturers worked with designers and maintainers to ensure that a part or system was not only designed correctly, but it could be manufactured, and it could be maintained while that part or system was still on the drawing board.

While not a revolutionary idea, collocated IPTs does make good common sense. It improves communication and avoids problems and rework later on.

CATIA and COMOK

The computer revolution has changed the detail design process of the aircraft. With the IBM-Dassault Systemes-designed Computer Aided, Three-Dimensional Interactive Application (CATIA), the aircraft designer can design the parts of the F-22 as a solid object, not just lines on a flat page.

With COMOK (a team-developed computer mockup simulation), the designer can visualize every aspect of the design including complex routing for wires, tubes, and cables. There is no 'hard' mockup of the F-22.

These computer programs allow the design engineer and the manufacturing engineer actual look inside the structure before it is built.

More than just a visualization, the computer data that creates these images are precisely stored design measurements that can be transferred, again by computers, between the team's locations in Marietta, Ga., Fort Worth Texas, Seattle, Wash., and West Palm Beach Fla., and East Hartford, Conn. and supplier locations all around the country.

Parts of the aircraft fit remarkably well when received in Marietta, where final assembly takes place, even though no master tool was sent to trial fit the pieces. In fact more than 270 master tools have been eliminated as confidence in the 3-D tools grew. As part of the IPT process, the team found that it could hold tolerances to 1/6000 of an inch on parts.

Numerical Control (NC) Programming

The numerical control (NC) machines that mill the parts for F-22 use the same data set as the CATIA design tools, and there are no errors in translation between the two. So, by removing variation in the data set, one-half of the possibility of variation between parts is eliminated. The possibility of variation because of the machine fabricating the part remains, however.

Avionics Racks

The F-22's avionics have the computing power of two Cray supercomputers, and they produce a large amount of heat. The racks that hold the avionics are not only thermal management units - the F-22's avionics are air cooled, liquid cooled, and liquid flow-through cooled, they are also structural parts of the aircraft. The racks have to hold the modules in the correct position in the backplane and they cannot leak, even when the aircraft is maneuvering violently at forces up to nine-Gs.

More than 250 avionics racks had been built as of early 1997, out of a total of just under 300 racks necessary for the current Engineering and Manufacturing Development (EMD) phase of the program. The avionics racks are fabricated and assembled in Marietta, Ga.

Tooling

Unlike many other aircraft programs, where parts move from tool to tool, a majority of F-22 tools move with the part. This keeps the part from flexing or not being aligned properly when it is moved to the next tool in the assembly process.

The F-22 tooling is also designed to be as ergonomic as possible. The tools are elevated to allow workers to get under them without stooping and they are well lit. In final assembly, the workstands move on integral castors to allow them to be pushed easily against the aircraft.

The final assembly line in Marietta is sized for producing the EMD aircraft and the F-22s in the low-rate production lots. At high-rate production (48 aircraft per year), it will only be necessary to add duplicates of some of the existing tooling. The team's design goal was to build the first EMD aircraft as closely as possible to the first production aircraft

Composite tools for building composite parts are not durable, so the team opted to build Invar steel tools. This allowed for tools that can be reused over and over. The Invar tools contain all the necessary thermocouples for measuring the temperature of the part, and the necessary connections are also all in one place.

Of the composite parts produced for the first aircraft and those following after, as an example, Lockheed Martin Aeronautical System achieved a 90% usable first part yield, and 78% of the parts were defect-free. Most of the defects were found using non-destructive inspection (NDI) and could be corrected.

Aircraft Materials Composition

The aft fuselage of the F-22 is mostly high strength titanium, as it has to hold the aircraft's F119 engines, and it must be able to withstand the high temperatures the engines create. The mid fuselage transitions from titanium (in the larger, load-bearing bulkheads) to forged aluminum bulkheads and aluminum frames. The forward fuselage contains a composite fuel tank (the F-1 tank behind the pilot's ejection seat) and is made of machined aluminum. The wings are made of composite spars and skins with titanium reinforcement.

Assembly Processes

Two computerized systems that have been implemented at Lockheed Martin Aeronautics Company in Marietta are being utilized in the process of assembling the F-22, DASS and MATS.

The Dynamic Assembly Scheduling System (DASS) is a simulation of the entire factory. A manager loads in data - who is out sick, what tools are down for maintenance, etc. - and the system runs a simulation of the work day and it then resequences the work to what can be done on that particular day.

The Manufacturing Assembly Tracking System (MATS) is a television-sized monitor that allows the individual worker to call up the work task for the day and the system provides the instructions to accomplish it. The worker can look at diagrams of the procedure and can zoom in to look at specific parts. A temporary drawing can be printed if necessary, but the drawing is discarded at the end of the day. That way, only the most current drawing is used. The MATS terminal also serves as an electronic bulletin board, allowing workers to view current news, company staff meeting notes, etc.

In the Final Assembly Area, workers are not allowed to use the "own" tools. All of tools are shadowboxed in company-issued toolboxes and when a worker removes a tool, he or she places a chit with a photograph and the employee's number on it in the tool's slot. All of the tools are accounted for at the end of each shift and the boxes are locked until the next shift comes in. This eliminates the possibility of a tool being left in the F-22 and creating a Foreign Object Debris problem.

F-22 AIR VEHICLE COMPONENTS

Forward Fuselage and Empennage

Lockheed Martin Aeronautics Company in Marietta, Ga. builds the forward fuselage of the F-22. It consists of the structure aft of the radar bulkhead, the cockpit area, nose wheel well, and F-1 fuel tank. It consists of approximately 3,000 parts made mostly of aluminum and composite materials. The forward fuselage also contains wiring harnesses, tubing, cockpit instrument fixtures, avionics racks, and canopy mounts.

The F-22's forward fuselage is just over 17 feet long, slightly wider than five feet inches wide at its widest point, five feet, eight inches tall, and weighs roughly 1,700 pounds.

Built up in two sections, the forward fuselage is joined together by two long and relatively wide side beams and two longerons that run the length of the assembly. The beams, made of composite material, also provide an attachment point for the F-22's chine, a fuselage edge that provides smooth aerodynamic blending into the intakes and wings. The 17-foot-long aluminum longerons form the sills of the F-22's cockpit and the canopy will rest on them.

The canopy is also built up in Marietta, and is approximately 140 inches long, 45 inches wide, 27 inches tall, and weighs approximately 350 pounds. Seven test canopies were built for the sled test program.

The integrated forebody, also referred to as the radome, is composite. It is manufactured by Lockheed Martin Aeronautics Company in Palmdale, Calif.

The empennage consists of the vertical and horizontal tails. The verticals are a multi-spar configuration internally, and with a hot isostatic pressed (HIP) cast rudder actuator housing. The edges and rudder are made of composites., and both parts have embedded VHF antennas, as well as other antennas. The rudders can also be towed inward to act as a speedbrake for the F-22.

The horizontal surfaces, known as stabilators, are made of honeycomb materials with composite edges. They are all-moving assemblies and are deflected by the Composite Pivot Shaft (see CPS in Materials and Processes section).

Mid-Fuselage

The mid fuselage is the largest and most complex of the F-22 assemblies. It is approximately 17 feet long, 15 feet wide, and 6 feet high, and weighs approximately 8,500 pounds as shipped.

The mid-fuselage is considered the heart of the F-22 as almost all systems pass through this section, including the hydraulic, electrical, environmental control, and auxiliary power systems, as well as the aircraft's fuel. In addition, there are three fuel tanks, four internal weapons bays (the two side bays, and the two sections of the main weapons bay that is separated), the 20-mm cannon, and the auxiliary power unit (APU).

Mid fuselages of F-22 EMD aircraft are assembled in the north end of the Lockheed Martin Aeronautics Company in Fort Worth, Texas. Employees at the Fort Worth plant fabricate most of the composite parts and assemblies, tubes, and harnesses in the mid fuselage.

Most of the aluminum machined parts are made by Lockheed Martin Aeronauticsl Company in Marietta, Ga. Subcontractors spread throughout the United States supply titanium parts, standard hardware, and system components for the mid fuselage.

Lockheed Martin is using a modular approach to assemble the mid-fuselage. Three modules, which are simultaneously assembled prior to mating, make up the mid-fuselage structure. This modular approach provides greater efficiency and access to the densely packed mid fuselage structure.

A unique tooling process assembles each module vertically, which helps fit parts in the high tolerance locations of the mid fuselage. An elevator that runs in the air inlet ducts provides access within the structure. The modules are then switched to the horizontal position for mating. The initial vertical assembly provides optimum manpower to the module, decreasing the overall assembly span time, which translates into significant dollar savings.

Like the entire aircraft, the F-22 mid-fuselage was developed in an Integrated Product Team (IPT) environment. Members of the teams include personnel from various disciplines. The process has worked extremely well for the program, resulting in a significant decrease in engineering changes and scrapped parts.

The composition of the F-22 airframe uses a unique combination of materials to provide the best cost and weight balance. Unlike conventional aircraft, only 35% of the F-22 mid fuselage structure is aluminum. Composites make up 23.5% and titanium is nearly 35%. One of the four one-piece titanium bulkheads is the largest single piece of titanium ever to be used on an aircraft.

This optimum mixture was the result of extensive material trade studies that evaluated cost and weight benefits of various design, material and manufacturing concepts. A critical part of these studies was an extensive analysis of thermal expansions that can induce significant stresses into the airframe This study reduced the risk that is normally associated with use of multiple materials in airframe design.

Because of its width, the mid fuselage has to sit at almost a 45-degree angle in its reusable metal shipping container. This is so its shipping box will fit on a flatbed truck and still be allowed on roads from Texas to Georgia.

Aft Fuselage

Boeing began major assembly of the aft fuselage for the world's first F-22 in June 1996 at its Developmental Center in Seattle, Wash. Boeing began the process by loading the left-hand forward boom, a large component that contains fuel and carries structural loads, into the aft fuselage assembly fixture.

The F-22 aft fuselage houses the two Pratt & Whitney-built F119 engines that power the F-22. It also contains all or part of the aircraft's environmental control system and fuel, electrical, hydraulic, and engine subsystems. The aft fuselage is designed to withstand supersonic speeds for extended periods of time and extremely 'high-g' maneuvers.

The aft fuselage is 67 percent titanium, 22 percent aluminum and 11 percent composite by weight. A completed aft fuselage weighs 5,000 pounds and measures 19 feet long by 12 feet wide.

Approximately 25 percent (by weight) of the aft fuselage is comprised of large electron beam welded titanium forward and aft booms. The largest of these booms, the forward boom, is more than 10 feet long and weighs approximately 650 pounds The welded booms of the aft fuselage are extremely weight-efficient and reduce the use of traditional fasteners by approximately 75 percent.

The aft fuselage is shipped to Marietta in a reusable metal container that fits upright in a rail car, or can be placed on its side for shipping by cargo aircraft. The first aft fuselage was delivered to Marietta aboard a Lockheed-built C-5 Galaxy.

Wings

Boeing began assembly of the left-hand wing for the first F-22 in January 1996 when machinists loaded wing attachment parts for external fuel tanks and weapons pylons into an assembly tool.

By weight, the Boeing-built portion of the wing is 42 percent titanium, 35 percent composite, and 23 percent aluminum, steel, and other materials in the form of fasteners, clips, and other miscellaneous parts. Each wing weighs approximately 2,000 pounds.

Each of the wings measures 16 feet (side-of-body) by 18 feet (leading edge) and is roughly triangular in shape. The wings together give the F-22's planform a modified delta shape. The wings are designed to cruise at supersonic speeds for extended periods of time and withstand extremely 'high-g' maneuvers.

The wings incorporate structural design modifications made early in the development program. After analyzing the results of live-fire tests simulating severe combat damage, engineers chose to reinforce the wing by replacing every fourth composite spar with one made of titanium. The titanium reinforcements ensure that the F-22 will be more survivable in combat. The wings are designed to be interchangeable from airplane to airplane.

Principal suppliers to Boeing on the wing include Dow-United Technologies of Wallingford, Conn. (composite sine wave spars); Howmet of Norfolk, Va. (side-of-body rib and aileron support castings); Schlosser of Redmond, Ore. (pylon rib castings) and Curtiss Wright of Fairfield, N. J. (leading edge flap drive system).

The wing shipping containers are designed to transported either by rail (the preferred method) or by transport aircraft. The wings for the first F-22 were shipped to Marietta via Air Force transport aircraft.

SPECIALIZED MANUFACTURING AND

FINAL ASSEMBLY FACILITIES

Precision Drilling Center

The F-22 factory at Boeing introduces the use of an automated, laser-guided machine for drilling holes in components where fasteners are still required.

Originally developed for the B-2 bomber program, the system uses a laser tracker with a targeting feature and automated data feedback software to guide the drill to exactly the correct location before drilling, It does so by measuring the relative position of the drill to the structure and automatically making positional adjustments.

Operated by machinists, the system drills nearly 2,500 holes into the aft fuselage structure. The location, size, and depth of the holes are controlled by engineering data fed into a computer. The holes are used for attaching the upper composite skins and lower engine-bay doors to the aft fuselage structure.

Precision drilling is also being used to drill 14,000 holes in each F-22 wing set as well, which allows for attachment of the composite wing skins to the titanium and composite substructure.

Final Assembly

Final assembly operations for the new fighter will take place in the 3.5-million-square-foot B-1 building (which has been in near-continuous use since 1943) at Lockheed Martin Aeronautics Company in Marietta. However, other things necessary for the F-22 specifically - such as composite parts fabrication, painting, radar cross section verification, ground-based engine runs, and flight operations - take place in nearly $31.5 million worth of facility improvements that have been completed or will soon be finished. Most of the facilities improvements are located near the company's flight line.

Radar Cross Section (RCS) Verification Facility

The largest of the new buildings is the radar cross section (RCS) verification building. This 50,000 square-foot fully enclosed structure will be used to test the 'stealthiness' of each F-22 when it comes off the assembly line.

The main section of this building feature a 45-foot-diameter turntable with precise positioning capability that will allow for testing of full-size aircraft. This section of the building will measure 150 x 210 feet and will be 45 feet high. The facility will have a separate 60 x 210 foot anechoic chamber for aircraft antenna testing.

Burns & McDonald Engineers of Kansas City, Mo., designed the structure. It is expected to be operational by late summer 1997.

Robotic Coatings Facility

The other new building in Marietta to support the F-22 is the robotic coatings facility. This 43,000 square foot facility, which is fully compliant with all environmental regulations, will have separate areas for materials handling, subassembly painting, and a large bay where most of the exterior of the aircraft will be painted.

Two robotic painting systems will be used in the building, which will be designated as L-64 ('L' indicates a Lockheed Martin-owned building, '-64' is the next available number). The subassembly painting area will utilize a small, six-axis spray-head robot mounted on a 25-foot long track. This robot will be used to paint parts such as panels, doors, and the F-22's control surfaces before those parts are installed on the aircraft.

The aircraft's exterior will be painted with a standard six-axis spray head mounted on a hydraulically-operated arm that can be raised and lowered and is, itself, attached to a movable platform. This wire-guided platform, called an Automated Guided Vehicle (AGV), features electric drive wheels and hydraulic stabilizing jacks and will be positioned at several points around the aircraft as it is being painted.

The large robot has 28-foot horizontal reach and the spray head can be raised as high as 26 feet. The large robot, developed by Pratt & Whitney Waterjet, Inc., is an offshoot of the Large Aircraft Robotic Paint Stripping (LARPS) system developed under the Air Force's Manufacturing Technology (MANTECH) program for the Oklahoma City Air Logistics Center at Tinker AFB, Okla.

The robot's software will be verified on a full-scale mockup of the F-22 called the Finish Application Mockup (FAM), rather than risk an aircraft. The highly realistic FAM includes panel lines and sits at exactly the same height as the real aircraft. Once the paint robot's software is proven, the FAM will be used to test the systems in the RCS Verification Building.

The large robot allows for precise application of the aircraft's paint. Unlike many other aircraft, where a base coat is applied over the entire aircraft, and then the camouflage coat is added on top of that, the F-22's two-tone camouflage scheme of dark gray on a light gray will actually be applied separately.

The robot first paints the light gray surrounding what will be a camouflage area, but leaves a hole where the dark gray will go. It then goes back and adds the dark gray. This saves paint, and more importantly, doesn't add additional weight anywhere on the aircraft.

L-64 will measure 90 x 100 feet and will cost approximately $16.5 million (including the robots). Choate Construction of Atlanta was the prime contractor and operations began in the building in late 1996. As the F-22 manufacturing program expands, there are plans for a second painting facility to be built adjacent to the first.

Hush House

A third new facility on the Lockheed Martin flight line isn't actually new at all. The engine noise attenuation facility (more commonly known as a 'hush house') is being used for ground-run tests of each F-22's twin Pratt & Whitney F119-PW-100 engines was formerly located at McConnell AFB, Kan.

The facility, designated B-22 (the 'B' indicates a government-owned building) was disassembled, trucked to Marietta, and reassembled across the ramp from both of the other new buildings. Vita-Link was the prime contractor for the move, and Burns & McDonald provided engineering support.

Other Facilities

One feature unique to high-performance aircraft is ejection seats. In order to safely store and handle the pyrotechnics necessary for the F-22's ACES II ejection seats, the existing B-66 building will be modified. This small building, which was formerly used to monitor C-5 ground engine runs, is of sturdy construction (thick walls, etc.) and will contain an explosion should one occur.

The final major facility upgrade on the flight line is improvements to the existing L-10 building. This building houses flight test (and later production flight) operations for the F-22. The building will have the necessary utilities to support four aircraft at the same time. Pratt & Whitney will also have an engine buildup and repair area. Control room and locker area space will also be included.

The facility improvements for F-22 also took place in several other buildings of the Air Force-owned, Lockheed Martin-run plant. Office and Integrated Product Team support spaces for F-22 manufacturing personnel were constructed in the main B-1 building near the F-22 assembly line in 1995. This project was one of the first undertaken.

Another project completed in 1995 was activation of the composite parts fabrication area in the existing L-11 building, which was once used for assembly of JetStar executive transports.

The final major facilities improvement at Lockheed Martin Aeronautics Company was the renovation of the B-4 building, which is located near the B-1 main assembly building. Two non-flyable F-22 airframes (the static and fatigue test articles) will undergo ground testing in one high bay of this building, and, in order to accomplish those tests, a new hydraulic system was installed.

Now lets review weapons systems-

For its primary air-to-air role, the F-22 will carry six AIM-120C and two AIM-9 missiles. For its air-to-ground role, the F-22 can internally carry two 1,000 pound-class Joint Direct Attack Munitions (JDAM), two AIM-120C, and two AIM-9 missiles. With the Global Positioning System-guided JDAM, the F-22 will have an adverse weather capability to supplement the F-117 (and later the Joint Strike Fighter) for air-to-ground missions after achieving air dominance.

The weapons bay played a huge role in the design evolution of the F-22. The aircraft is essentially wrapped around its internal bay, which is an essential characteristic of the F-22's stealthy design. The limited space drove the configuration of the launchers and acoustic suppression devices. Launching weapons from an internal bay is not a new problem. The F-111 and F-117 have internal bays as well as older aircraft like the F-102, F-105, and F-106. Historically, bay acoustics and weapon re-contact with structure during separation have been issues. The F-22 has a requirement to launch weapons throughout the service envelope at roll rates up to 100 degrees per second. This is a groundbreaking requirement made even tougher by tight clearances and flow fields that result from internal carriage.

The F-22 carries its primary armament, the AIM-120C Advanced Medium-Range Air-to-Air Missile (AMRAAM) internally on the EDO Corp.-built LAU-142/A pneudraulic (pneumatic and hydraulic) launcher, called the AMRAAM Vertical Eject Launcher (AVEL). Six launchers mounted in the main weapon bays carry and launch the AMRAAMs. The AVEL is very stiff in order to control missile movement in the weapons bay and supply the proper ejection forces on the missile. The AVEL, which is made mostly of aluminum, has a nine-inch stroke, and ejects the missile out of the bay at more than 25 feet per second, with a force of 40Gs. The long stroke and high velocity are required to safely separate the missile from the aircraft in all combat conditions. Unlike conventional missile launchers, the AVEL requires no explosive pyrotechnics cartridges, (which means the AVEL requires less logistics support and maintenance) but instead uses the aircraft's hydraulic system to eject the missile. The entire missile launch sequence --door opening, AVEL ejecting the missile, missile ignition and flyout, door closing --takes just seconds.

The F-22's combat configuration is "clean", that is, with all armament carried internally and with no external stores. This is an important factor in the F-22's stealth characteristics, and it improves the fighter's aerodynamics by dramatically reducing drag, which, in turn, improves the F-22's range. The F-22 has four under wing hardpoints, each capable of carrying 5,000 pounds. A single pylon design, which features forward and aft sway braces, an aft pivot, electrical connections, and fuel and air connections, is used. Either a 600-gallon fuel tank or two LAU-128/A missile launchers can be attached to the bottom of the pylon, depending on the mission.

There are two basic external configurations for the F-22:

Four 600 gallon fuel tanks, no external weapons: This configuration is used when the aircraft is being ferried and extra range is needed. A BRU-47/A rack is used on each pylon to hold the external tanks.
Two 600 gallon fuel tanks, four missiles: This configuration is used after air dominance in a battle area has been secured, and extra loiter time and firepower is required for Combat Air Patrol (CAP). The external fuel tanks, held by a BRU-47/A rack are carried on the inboard stations, while a pylon fitted with two LAU-128/A rail launchers is fitted to each of the outboard stations.
An all-missile external loadout (two missiles on each of the stations) is possible and would not be difficult technically to integrate, but the Air Force has not stated a requirement for this configuration.

End-to-end weapons integration missile shots have had mixed results in testing, according to DOT&E. Four shots have demonstrated the capability to engage and destroy enemy aircraft in specific, discreet combat representative scenarios. However, three other shots indicated fire control deficiencies exist that need to be resolved in development. Some F/A-22 weapons separation, fully integrated guided missile test launches, and JDAM testing are planned to be done concurrently with IOT&E. JDAM employment is planned for follow-on test and evaluation, to be conducted after IOT&E. DOT&E believes that a large F/A-22 development risk, from both a technical and schedule perspective, lies in the integration of the avionics suite with realistic air-to-air and, eventually, air-to-surface weapons employment.

AIM-120 Advanced Medium-Range Air-to-Air Missile (AMRAAM)
The F-22's primary weapon is the AIM-120 Advanced Medium-Range Air-to-Air Missile (AMRAAM). This missile is a replacement for the AIM-7 Sparrow, which was developed in the 1950s, and was still in front-line service into the early 1990s. The AIM-120 was developed to provide an all-weather, all-launch environment capability for the F-22, as well as the Air Force's in-service F-15 Eagle and F-16 Fighting Falcon, and the Navy's F-14 Tomcat and F/A-18 Hornet.

The AIM-120 (which has no official nickname, but is called "Slammer" by pilots) is carried internally in the F-22's main weapons bay that is located on the underside of the fighter tucked under the inlets. The main bay is covered by two thermoset composite bifold doors that open outward. When the F-22 is in first-day-of-a-war combat configuration, all missiles are carried in the main weapons bay only. The typical combat load is six AIM-120C. Three in each side of the main weapons bay with the center missile staggered ahead of the inboard and outboard missiles. The F-22 can carry four of the older, longer-finned AIM-120A if necessary.

Each missile is carried on an EDO Corp.-built LAU-142/A pneudraulic (pneumatic and hydraulic) launcher, called an AMRAAM Vertical Eject Launcher (AVEL). The AVEL is substantial (nearly 113 pounds each) in order to minimize missile movement in the weapons bay. The AVEL, which is made mostly of aluminum, has a nine-inch stroke, and ejects the missile out of the bay at more than 25 feet per second with a force of 40 G (40 times the force of gravity) at peak acceleration. Unlike conventional missile launchers on other aircraft, the AVEL requires no pyrotechnics, and it requires less logistics support than other launchers.

The missiles are loaded from the opposite side of the aircraft AIM-120 Loading in Main Weapons Bay (missiles in the left side of the weapons bay are loaded from the right and visa versa), in order to clear the open main weapons bay doors. The current MJ-1 load vehicle (called a jammer) is used to load the missiles into the F-22. The missiles are staggered in the bay so fins on adjacent missiles do not interfere with each other when they are launched.

The missile gets target information from the aircraft prior to launch via a Military Standard (Mil Std) 1760 data bus. Once launched, the missile can operate independent of the launch aircraft, as it has its own inertial guidance system and an active radar, allowing the F-22 pilot to launch the missile and leave the area, thus avoiding a close-in dogfight. However, if necessary, the missile can also receive mid-course target updates from the launch aircraft. The entire launch sequence (door opening, AVEL ejecting the missile, missile ignition and flyout, door closing) takes just seconds. The combination of the aircraft's stealth characteristics, its integrated avionics, and the AIM-120 missile gives the F-22 a "first-look, first-shot, first-kill" capability.

AIM-9M Sidewinder
The F-22's short-range missile armament is the AIM-9M Sidewinder. This missile has been continuously updated since its forerunner (then designated N-7) destroyed a radio-controlled drone in a test at China Lake, Calif., in September 1953. Developed essentially from spare parts by the Naval Ordnance Test Center, Sidewinder entered service with the Air Force in 1956. Today, the AIM-9 is used on nearly every U. S. Air Force and Navy fighter (including F-15, F-16, A-10, F-14, and F/A-18) and those of many allied nations. It can even be fired from several types of military helicopters. Well over 150,000 Sidewinders have been built.

The AIM-9M is currently the only operational Air Force variant. This model has all-aspect (any direction) intercept capability. It also has improved defenses against infrared countermeasures, enhanced background discrimination capability, and a reduced-smoke rocket motor. These upgrades increase the missile's ability to locate and lock-on a target and decrease the missile's chances for detection. Deliveries to the Air Force began in 1983. A new variant, AIM-9X, is now in development. This missile will retain many of the Sidewinder's capabilities while strengthening the design with airframe improvements and advanced seeker technology, including staring focal plane arrays, adaptive compensation techniques, and infrared signals processing.

On the F-22, one AIM-9 is carried in each of the aircraft's side weapons bays, which are located on the outside of the engine inlets. There are no plans to carry the AIM-9 in the F-22's main weapons bay. The side bays are each covered by two thermoset composite doors that run the length of the compartment and are hinged at the top and bottom of the bay. Although AIM-9X is slightly longer than the AIM-9M, it will still fit in the F-22 without modification to the side weapons bays.

The missiles are carried on a Lockheed Martin Tactical Aircraft Systems-built LAU-141/A hydraulic launcher, called a Trapeze Launcher. This launcher, which uses some components from the existing LAU-128/A launcher, is basically the wingtip launch rail from an F-16 with a swing out mechanism that extends rapidly. The LAU-141/A is also fitted with a missile motor plume deflector, which prevents damage to the side weapons bay as the missile launches off the rail. Each missile is loaded by opening the doors, extending the rail, sliding it on the rail, retracting the missile, and closing the doors. Nearly all Sidewinders are loaded manually, using a three-person load crew. AIM-9 loading for F-22 will be no different.

As the AIM-9 uses infrared guidance, the missile first has to acquire the target. To launch a Sidewinder from the F-22, the side weapons bay doors open; the Trapeze Launcher, with missile attached, extends to put the missile's seeker into the slipstream; the seeker acquires the target; the missile ignites and flies off the rail. The Trapeze Launcher then retracts, and the weapons bay doors close. Once launched, the F-22 pilot can leave the fight, as Sidewinder is autonomous, following its seeker to the target, after it leaves the launch rail. The entire Sidewinder launch sequence, from door opening to door closing, takes just seconds.

GBU-32 JDAM Joint Direct Attack Munition
JDAM is a tail guidance kit that converts existing unguided free-fall bombs into near precision-guided "smart" munitions. It also includes strap-on strakes that attach to the bomb's body for stability. Adding a new tail section containing an Inertial Navigation System (INS)/Global Positioning System (GPS) guidance control unit to existing inventories of Mk. 83 1,000-pound-class general purpose conventional bombs gives the F-22 a highly accurate, autonomous, high altitude all-weather conventional bombing capability. Currently, the JDAM tail guidance kit gives existing "iron bombs" a circular error probable (CEP, the measure of weapons accuracy) of under 15 meters, but a planned improvement program will give the weapon a CEP of considerably less than 10 meters. JDAM is intended for use on a variety of Air Force and Navy aircraft including B-1, B-2. B-52, F-15E, F-16, F-117, and F/A-18.

The F-22 can only carry the 1,000-pound class JDAM weapon. For the F-22, the JDAM tail guidance kit fits on the Mk. 83 1,000-pound-class conventional bomb. Weight of the Mk. 83 bomb and tail guidance kit is approximately 1,015 pounds The combination of the stealthy F-22 and the precision capability of the GBU-32 allows the F-22 pilot to drop the weapon from altitudes of approximately 40,000 feet to a range of approximately 15 miles.

The GBU-32 is only carried in the F-22's main weapons bay. A typical combat load consists of two GBU-32. One GBU-32 is carried inboard in each side of the main weapons bay. When loaded with GBU-32, there is still sufficient room in the F-22's main weapons bay to carry two AIM-120C air-to-air missiles (one in each side of the bay, in addition to the two AIM-9 Sidewinders in the side weapons bays), which means that even on a mission to attack ground targets, the F-22 retains significant air-to-air combat capability.

Each 1,000-pound-class GBU-32 will be loaded from the opposite side of the F-22 (the JDAM in the left side of the weapons bay is loaded from the right and visa versa), in order to clear the open main weapons bay doors. The current MJ-1 load vehicle (called a jammer) is used to load the GBU-32 into the F-22. The GBU-32 is carried on the Air Force's standard BRU-46/A bomb rack (which is built by EDO). The weapon is carried on the inboard side of the bay with an adjacent AIM-120C missile staggered on the outboard side. This is so tail fins on the bomb and the missile's wings do not interfere with each other when the weapons are either released or launched.

The GBU-32 gets target information from the aircraft prior to release via a Miltary Standard (Mil Std) 1760 data bus. JDAM can be dropped by an aircraft from up to 15 miles from the target. In addition to its own inertial guidance system, the weapon receives in-flight position updates from the 24-satellite GPS satellite constellation which help guide the bomb to the target. The GPS constellation provides 24-hour navigation information to military and civilian users. The GBU-32's autonomous operation allows the carrying aircraft to release the weapon and leave the area, thus avoiding an enemy's integrated air defense (surface-to-air missiles, antiaircraft artillery ("triple A"), and radars) system, but still delivering the weapon to the target.

M61A2 20-mm Cannon
The F-22's close-range weapon is the M61A2 20mm cannon and its associated components. The M61 is a proven gun, having been the U. S. military's close-in weapon of choice dating back to the 1950s. The F-104, F-105, later models of the F-106, F-111, F-4, B-58, all used the M61, as does the Air Force's current F-15 Eagle and F-16 Fighting Falcon, and the Navy's F-14 Tomcat and F/A-18 Hornet. The system is integrally mounted in the aircraft and located on the right side of the aircraft between the wing (top side) and fuselage. It is a fixed-forward firing mount. A gun door, located in the wing root area, is hydraulically controlled to open when firing the gun, which allows the rounds and blast pressure to clear the muzzle. A 480-round closed loop ammunition feed and storage subsystem is housed integrally under the right wing root/fuselage for easy ammo upload and download of empty casings. The gun system consists of the M61A2 gun, the Linear Linkless Ammunition Handling System (LLAHS), the hydraulic drive system, and the gun door/gun port and gas purge system.

The M61A2 is a lightweight version of the M61A1. Most of the weight savings was achieved by machining down the barrel thickness. The M61A2 is Government Furnished Equipment (GFE), that is, purchased by the government under separate contract and provided to the F-22 contractor team. Power to operate the gun is provided by hydraulic pressure supplied by the aircraft's hydraulic system. Each of the gun's six barrels fires only once during each revolution of the barrel cluster. The six rotating barrels contribute to long weapon life by minimizing barrel erosion and heat generation. The gun's rate of fire, essentially 100 rounds per second, gives the pilot a shot density that will enable a "kill". With 480 rounds, the pilot has roughly five shots with the gun.

The inherent capabilities of the F-22 (stealth, advanced avionics, supercruise) and advanced air-to-air missiles such as AIM-120 AMRAAM and AIM-9 Sidewinder, will likely render use of the gun unnecessary in combat. However, as history has demonstrated (most glaringly with the F-4 in Vietnam), at some point, the air battle comes down to a dogfight, and the M61A2, along with the F-22's superior maneuverability, gives the pilot one more option.

The General Dynamics Armament System-developed Linear Linkless Ammunition Handling System (LLAHS) consists of a 480 round ammunition storage container with drive train and integral access (reload) unit, an ammunition conveyor assembly, a hydraulic drive unit, a rounds limiter, and a last round switch. There are no links between rounds (hence the term "linkless") an innovation that eliminates completely any potential jamming of the gun breech. Ammunition is transported from the container to the gun breech by a direct extension of the carrier chain, which also carries the empty cartridges back to the ammunition storage container to form a closed loop system. The LLAHS is loaded manually from the ground. The rounds limiter is an electromechanical device that is preset to limit the number of rounds that can be fired on a training flight. The last round switch shuts down the gun when it senses the empty casing of the first round fired. The LLAHS is located very near to the aircraft's center of gravity, so by retaining the casings, even after all the rounds are fired, there is no change forward or aft to the aircraft's center of gravity. Also, by not ejecting the casings, a potentially serious foreign object debris (FOD) problem (i.e. ingesting casings into the engines) simply does not exist.

The gun hydraulic drive unit is a 42 horsepower fixed displacement motor sized to achieve a 6,000 round per minute gun firing rate at all flight loading conditions. The gun port door is mechanized such that is opened to provide an exit path out of the aircraft for the projectiles. It is activated when the pilot squeezes the trigger on the control stick (the first detent) in the cockpit. The door opens to 90 degrees and is activated in milliseconds. When the trigger is released by the pilot (or the last round switch engaged), the door is commanded to close. It takes several seconds for the door to close completely. The door is an aid to the F-22's stealth characteristics, and it helps the aircraft's aerodynamics by reducing drag. The gun port is a steel casting that is located under the port door. It is used to protect the aircraft and its structure from gun muzzle blast by deflecting projectiles up and away from the aircraft surface. If a misfire occurs in the one-half portion of the gun port, it is designed to capture the projectile.

The gun gas purge system consists of an actuated purge door that opens at the same time as the gun port door. The purge door, located on the fuselage side near the gun breech, forces outside air (ram air) into the aircraft when opened and a static screened vent (on the top of the fuselage) allows gun gas (which is mostly hydrogen, and as such, explosive) and ram air to exit overboard. When the trigger is released by the pilot (or the last round switch is engaged), the door is commanded to close M61A2 20-mm Gun System for F-22.

F-22 Carriage Capability
The F-22's combat configuration is "clean", that is, with all armament carried internally and with no external stores. This is an important factor in the F-22's stealth characteristics, and it improves the fighter's aerodynamics by dramatically reducing drag, which, in turn, improves the F-22's range. The F-22 has four under wing hardpoints, each capable of carrying 5,000 pounds. A single pylon design, which features forward and aft sway braces, an aft pivot, electrical connections, and fuel and air connections, is used. Either a 600-gallon fuel tank or two LAU-128/A missile launchers can be attached to the bottom of the pylon, depending on the mission.

There are two basic external configurations for the F-22: Four 600 gallon fuel tanks, no external weapons: This configuration is used when the aircraft is being ferried and extra range is needed. A BRU-47/A rack is used on each pylon to hold the external tanks. Two 600 gallon fuel tanks, four missiles: This configuration is used after air dominance in a battle area has been secured, and extra loiter time and firepower is required for Combat Air Patrol (CAP). The external fuel tanks, held by a BRU-47/A rack are carried on the inboard stations, while a pylon fitted with two LAU-128/A rail launchers is fitted to each of the outboard stations. An all-missile external loadout (two missiles on each of the stations) is possible and would not be difficult technically to integrate, but the Air Force has not stated a requirement for this configuration.

The LAU-128/A rail launcher is the standard rail launcher used today on the F-15 and can carry either of the missiles used on the F-22, AIM-120 AMRAAM or AIM-9 Sidewinder. However, both missiles carried on the fire missile adapter configuration for F-22 must be the same type for aircraft weight and balance considerations. The 600-gallon fuel tanks are similar to the same external tanks that are used on the current F-15 Eagle. However, a new tank is being developed that has baffles in it to prevent the fuel from sloshing. This gives the tank better center of gravity control, which allows for safe jettisoning of the tanks. The BRU-47/A rack is not the same type of rack that is used internally on the F-22 to carry the GBU-32 1,000-pound class Joint Direct Attack Munition (JDAM), although they are similar and both are currently in use. However, there are no plans to carry JDAM externally on F-22. The BRU-47 will only be used to hold the external fuel tanks.

The pylon itself is designed for minimal impact on aircraft performance. If it becomes necessary for the pilot to jettison the external stores, the entire pylon is jettisoned along with the tank or missile launch rails. The pylon has an aft pivot, so when the stores are jettisoned, the forward attach point is released first, the pylon rotates on the pivot, and then the aft pivot is released. This motion allows the pylon, along with the tank or launch rail to clear the aircraft when it is released into the slipstream.

**Defcon 6** · 19 Jan 06, 21:35

Now lets review the F-22 Avionics-

Avionics share as large a part in the success of a fighter as the ability to maneuver and fly fast, or to "turn and burn." The design issues that had to be addressed involved solving the technical and organizational challenges of running the program. Also crucial to the design, was the reduction of pilots' "housekeeping" responsibilities.

The F-22 will have the first integrated avionics suite ever flown on a combat aircraft. The Northrop/Grumman-Texas Instruments APG-77 radar, Lockheed Martin electronic warfare suite and the TRW communications/navigation/IFF subsystems are all included.

The requirements for the F-22's avionics system are derived from the F-22 Weapon System Concept, the guiding design principles for the overall weapons system. The integrated avionics system is one of the key elements (the others being stealth, maneuverability, and supercruise) that will give the F-22 the tactical advantage against the threats of the future.

The avionics system requirements are based on zones of operational interest. These zones, based on enemy and own ship capabilities, determine the information requirements for each object encountered in the mission. Today's fighters have some of the same sensing capabilities and subsystems to be controlled, but their federated architecture (that is, each avionics function has its own processor and essentially works independently) makes the pilot the integrator of data and the manager of all the supporting subsystems.

The F-22 operational concept, and the sophistication of the various systems requires integration at many levels, including sensor control, sensor data fusion, the architectural components that support these functions, and the displays that are the primary means of communication with the pilot. The key attributes of the avionics system are driven by the other weapon system characteristics such as stealth, supercruise, reliability, availability, and need for growth capacity.

Integrated avionics means different things to different people.

To the pilot, it means all the information is coordinated and available from a single source.
To the software engineer, it means access to shared data about the situation, the mission, and the aircraft systems.
To the hardware designer, it means common modules in a single backplane with the connectivity and bandwidth to support the required processing.
Coherent presentation and control (the pilot's view of integration) is not simply a way of organizing functions or routing lots of data to a single display. It actually includes additional functionality, such as situation assessment and weapons fire control. The software view of integration means that the various functional pieces of the software must have efficient access to globally coherent information, such as track files, navigation data, mission data, and aircraft system status information. A hardware architecture built on common components, common modules, standard buses, and common operating system provides the infrastructure for the processing and communication between the processes described above. In addition, modular approach allows for easy expansion of capacity and capability, fault tolerance, and reconfiguration.

Translating the system requirements into a producible, affordable, and maintainable design was the work of the Engineering and Manufacturing Development (EMD) program. The basic concept, derived from the Pave Pillar program in the 1980s (which included development of Integrated Communications, Navigation, Identification Avionics (ICNIA) and Integrated Electronic Warfare System (INEWS) systems) was to provide all the signal and data processing resources in a central collection of modular processors, linked to the sensors, subsystems, and pilot by high-speed data busses. The F-22 architecture provides just such a system, interfaced to the air-cooled, flight safety critical systems such as the flight control system.

The TRW Communications/Navigation/Identification (CNI) system includes an intra-flight datalink, JTIDS Joint Tactical Information Distribution System link, and an Identification Friend or Foe (IFF) system. Boeing is responsible for mission software and avionics integration. The aircraft has a Litton LTN-100G laser gyroscope inertial reference, a global positioning system and a microwave landing system.

The F-22's avionics suite features extensive use of very high-speed integrated circuit (VHSIC) technology, common modules, and high-speed data buses. The avionics suite is a highly integrated system maximizing performance allowing the pilot to concentrate on the mission, rather than on managing the sensors as in current fighters. Technologies incorporated in the F-22 include a Common Integrated Processor (CIP), a central "brain" with the equivalent computing throughput of two Cray supercomputers; shared low-observable antennas; ADA software; expert systems; advanced data fusion-cockpit displays; integrated electronic warfare system (INEWS) technology; integrated communications, navigation, and identification (CNI) avionics technology; and fiber optics data transmission. Nearly all of these elements were demonstrated during dem/val in a prototype architecture.

Common Integrated Processor (CIP)

The Hughes-built Common Integrated Processor (CIP) serve as the "brains" for the F-22's totally integrated avionics system. CIPs are the central, networked computers that enable the integration of radar, electronic warfare, and identification sensor data, as well as communication, navigation, weapon, and systems status data into coherent, fused information for communication to the pilot via multi-function displays. Rather than radar, the electronic warfare system, and the electronic warfare system having individual processors, the CIP supports all signal and data processing for all sensors and mission avionics.

The CIP modules have the ability to emulate any of the electronic functions through automatic reprogramming. For example, if the CIP module that is acting as radio dies, one of the other modules will automatically reload the radio program and take over the radio function. This approach to avionics makes the equipment extremely tolerant to combat damage as well as flexible from a design upgrade point of view.

There are two CIPs in each F-22, with 66 module slots per CIP. The CIPs (which is quite literally the size of a oversized bread box) are liquid cooled avionics racks containing both signal processing and data processing modules inserted into common backplane. They have identical backplanes, and all of the F-22's processing requirements can be handled by only seven different types of processors. There are 33 signal processors and 43 data processors interconnected via a fault-tolerant network. Each processing element is manufactured and packaged as an approximately 6x7x3/8ths inch line replaceable module (LRM) for ease of flightline maintenance.

Each module is limited by design to only 75 percent of its capability, so the F-22 has 30 percent growth capability with no change to the existing equipment. Currently, 19 of 66 slots in CIP 1 and 22 of 66 slots in CIP 2 are not populated and are available for growth. There is space, power and cooling provisions in the aircraft for a third CIP, so the requirement for a 200 percent avionics growth capability in the F-22 can be easily met. There is coordinated plan for technology growth that will help keep the CIP at state-of-the-art levels. As electronics continue to get smaller and more powerful, it is conceivable that there could be 300 percent increase in avionics capability.

The exponential explosion of computer technology in recent years has allowed the F-22 team to radically alter every aspect of the program from detailed design through manufacturing, communication, and into the cockpit itself. An example of the effect of the advances in computer technology is a comparison between the computers used in the Lunar Module and those used in the F-22. The Lunar Module's computers operated at 100,000 operations per second and had 37 kilobytes of memory. Today, the F-22's Common Integrated Processor main mission computers operate at 10.5 billion instructions per second and have 300 megabytes of memory. These numbers represent 100,000 times the computing speed and 8,000 times the memory of the Apollo moon lander.

AN/APG-77 Radar

The AN/APG-77 radar is the F-22's primary sensor and is a long-range, rapid-scan, and multi-functional system. A Northrop Grumman-led joint venture with Raytheon is developing the active-element electronically scanned array radar. Northrop Grumman is also responsible for the radar sensor design, software, and systems integration.

The AN/APG-77 radar is an active-element, electronically scanned (that is, it does not move) array that features a separate transmitter and receiver for each of the antenna's several thousand, finger-sized radiating elements. Most of the mechanical parts common to other radars have been eliminated, thus making the radar more reliable. This type of antenna, which is integrated both physically and electromagnetically with the airframe, provides the frequency agility, low radar cross-section, and wide bandwidth necessary to support the F-22's air dominance mission. The radar is key to the F-22's integrated avionics and sensor capabilities. It will provide pilots with detailed information about multiple threats before the adversary's radar ever detects the F-22.

The AN/APG-77 radar a novel type of electronically scanned phased array. In what is likely to be the most advanced airborne radar in the world, individual transmit and receive modules are located behind each element of the radar array. The transmit function of the solid-state microwave modules supplants the traveling wave tubes used in prior radars like the APQ-164. The active, electronically scanned array (ESA) configuration has a wider transmit bandwidth while requiring significantly less volume and prime power. The system represents about half the weight of an equivalent passive ESA design. Each of the hundreds of individual solid-state devices generates only small amounts of power, but the aggregate for the entire array is substantial.

The F-22 s APG-77 electronically scanned array antenna is composed of several thousand transmit/receive modules, circulators, radiators and manifolds assembled into subarrays and then integrated into a complete array. The baseline design used thousands of hand-soldered flex circuit interconnects to make the numerous radio frequency, digital, and direct current connections between the components and manifolds that make up the subarray. Northrop Grumman Corporation, of Baltimore, MD, has developed an improved manufacturing process for F-22 aircraft radar components. The new process could result in a cost avoidance of nearly $87 million on the planned production run for the aircraft. By replacing the hand-soldered flex circuit interconnects with automated ribbon bond interconnects, the first pass yield of the subarray assembly has been vastly improved.

The AN/APG-77 radar antenna is a elliptical, active electronically scanned antenna array of 2000 transmitter/receive modules which provides agility, low radar cross section and wide bandwidth. The radar is able to sweep 120 degrees of airspace instantaneously. In comparison to the F-15 Strike Eagle's APG-70 radar takes 14 seconds to scan that amount of airspace. The APG-77 is capable of performing this feat by electronically forming multiple radar beams to rapidly search the airspace.

The system exhibits a very low radar cross section, supporting the F-22's stealthy design. Reliability of the all-solid-state system is expected to be substantially better than the already highly reliable F-16 radar, with MTBF predicted at more than 450 hours.

The APG-77 radar offers significant advantages over previous combat radars. Among its most attractive benefits is the integration of agile beam steering. This feature allows a single APG-77 radar to carry out multiple functions, such as searching, tracking, and engaging targets simultaneously. Agile beam steering also enables the radar to concurrently search multiple portions of airspace, while allowing continued tracking of priority targets.

The Low Probability of Intercept (LPI) capability of the radar defeats conventional RWR/ESM systems. The AN/APG-77 radar is capable of performing an active radar search on RWR/ESM equipped fighter aircraft without the target knowing he is being illuminated. Unlike conventional radars which emit high energy pulses in a narrow frequency band, the AN/APG-77 emits low energy pulses over a wide frequency band using a technique called spread spectrum transmission. When multiple echoes are returned, the radar's signal processor combines the signals. The amount of energy reflected back to the target is about the same as a conventional radar, but because each LPI pulse has considerably less amount of energy and may not fit normal modulation patterns, the target will have a difficult time detecting the F-22.

The F-22 and its APG-77 radar will also be able to employ better Non-Cooperative Target Recognition (NCTR). This is accomplished by forming fine beams and by generating a high resolution image of the target by using Inverse Synthetic Aperture radar (ISAR) processing. ISAR uses Doppler shifts caused by rotational changes in the targets position to create a 3D map of the target. The target provides the Doppler shift and not the aircraft illuminating the target. SAR is when the aircraft provides the Doppler shift. The pilot can compare the target with an actual picture radar image stored in the F-22's data base.

Communications/Navigation/Identification (CNI)

The F-22's Communications/Navigation/Identification (CNI) 'system' is a collection of communication, navigation, and identification functions, once again employing the CIP for signal and data processing resources. Each CNI function has its associated aperture installed throughout the aircraft.

Inter/Intra-Flight Data Link (IFDL)

Included in the Communications/Navigation/Identification (CNI) system is an Inter/Intra-Flight Data Link (IFDL) that allows all F-22s in a flight to share target and system data automatically and without radio calls. The Inter/Intra Flight Data Link is one of the powerful tools that make all F-22s more capable. One of the original objectives for the F-22 was to increase the percentage of fighter pilots who make 'kills'. With the IFDL, each pilot is free to operate more autonomously because, for example, the leader can tell at a glance what his wing man's fuel state is, his weapons remaining, and even the enemy aircraft has targeted. Targets can be automatically prioritized and set up in a shoot list with one button push. A 'shoot' cue in the head up display alerts the pilot to the selected weapon kill parameters and he fires the weapons. Both a pilot's and wing man's missile flight can be monitored on the cockpit displays. Classical tactics based on visual 'tally' (visual identification) and violent formation maneuvers that reduce the wing man to 'hanging on' may have to be rethought in light of such capabilities. This link also allows additional F-22 flights to be added to the net for multi-flight coordinated attack.

Electronic Warfare (EW)

The Electronic Warfare 'system' is also a collection of apertures, electronics, and processors (again using the CIP) that detect and locate signals from other aircraft and controls the F-22's expendable countermeasures (chaff and flares). The EW aperture locations provide all-aspect coverage, and the system includes a missile launch detection capability.

The F-22's electronic warfare system includes a radar warning receiver and a Lockheed Martin Sanders missile launch detector.

Stores Management System (SMS)

The Stores Management System (SMS) controls weapons launch sequences, including door control (for the internal weapons carriage) and emergency weapons jettison.

Power Supplies

Boeing manufactures the power supplies for most of the F-22's electronic systems. The power supply modules designed for the F-22's avionics are cooled with polyalphaolefin (PAO) liquid coolant to carry away heat generated by the supplies' power-conversion process. The reduced temperature allows the component's power output to increase from 250 watts to 400 watts. Each module measure 6.41 inches by 5.99 inches by 0.58 inches and weighs 1.8 pounds.

Liquid Flow-Through Cooling

The PAO cooling concept also applies to all types of Line-Replaceable Modules (LRMs) in the CIP. Liquid flow-through cooling improves reliability, lending to an mean time between failures (MTBF) of 25,000 hours. The coolant, which is routed through the module, comes from the F-22's environmental control system (ECS). The LRM concept is the baseline for all of the power supply modules built for the F-22 to minimize maintenance time. Built-in diagnostic routines will pinpoint a failed power supply on an F-22 and allow maintenance personnel to remove it, replace it and verify proper operation within 15 minutes.

Avionics Racks

The avionics racks, located in the forward fuselage, contain the processing, not only for the mission avionics, but also for the Vehicle Management System (VMS) and Integrated Vehicle System Controller (IVSC). The flight worthy racks, including the liquid-flowthrough racks required for the CIP, are now in production.

Inertial Reference System (IRS)

Two Litton LN-100F ring laser gyroscopes in the forward fuselage provide the aircraft a self-contained method of knowing where it is. These inertial measurement units, placed nose to nose behind the radar on the aircraft's centerline, are operated off separate data buses to provide independent measurement data. In normal flight, IRS data is fused with Global Positioning System (GPS) data to provide an extremely reliable navigational capability. The IMUs are the only completely reliable source of data for the aircraft at attitudes above 30 degrees angle of attack (AOA). One of the IRS units feeds data directly into the CIP for gun control steering.

Software

The software that provides the avionics system's full functionality is composed of approximately 1.7 million lines of code. Ninety percent of the software is written in Ada, the Department of Defense's common computer language. Exceptions to the Ada requirement are granted only for special processing or maintenance requirements. The software development plan, though stretched as a result of past funding constraints, has remained essentially unchanged since the start of Engineering and Manufacturing Development.

The avionics software is integrated in three blocks, each building on the capability of the previous block. Each block cycle is a sequence of subsystem deliveries, integration testing at the Avionics Integration Lab (AIL) at Boeing (see AIL in the Test Facilities section), and then delivery to Lockheed Martin in Marietta, Ga., for final integration into the aircraft and check out, as well as support to the aircraft.

Block 1 is primarily radar capability, but Block 1 does contain more than 50 percent of the avionics suite's full functionality source lines of code (SLOC) and provides end-to-end capability for the sensor-to-pilot data flow. The fourth EMD F-22 was the first to have a full avionics suite, and it flew in mid 1999.

Block 2 is the start of sensor fusion. It adds radio frequency coordination, reconfiguration, and some electronic warfare functions. Block 2 was integrated into the aircraft in late 1999.

Block 3 encompasses full sensor fusion built on enhanced electronic warfare and CNI functions. It has an embedded training capability and provides for electronic counter-counter measures (ECCM). It was integrated into the aircraft in the spring of 2000. Block 3.1, which adds full GBU-32 Joint Direct Attack Munition (JDAM) launch capability and Joint Tactical Information Distribution System (JTIDS) receive-only capability, was integrated in April 2000.

The proposed Block 4 software will be post-Engineering and Manufacturing Development. It is scheduled to be integrated on the Initial Operational Capability F-22s and will likely include helmet-mounted cueing, AIM-9X integration, and Joint Tactical Information Distribution System send capability.

CIP hardware was available well before the subsystem application software code and unit test phases began for the Block 1 software. For some of the higher risk software, such as sensor data fusion, specific algorithm testbeds have been constructed, and prototype software, which is instrumented to measure performance (correlation times, accuracy, etc.). has been operational since the start of EMD.

Flying Test Bed (FTB)

The Flying Test Bed (FTB) represents an interim test environment between the controlled, but static environment of the ground labs, and the dynamic flight testing of the F-22. Sensor systems installed in the aircraft, CIPs, as well as operator consoles and instrumentation will be used to test avionics capabilities prior to release to the F-22.

Summary

In summary, the F-22 provides a revolution in avionics capability, suited to the mission and the airframe of the F-22. The avionics system design is nearing completion and key components already operational and delivered.

**Defcon 6** · 19 Jan 06, 21:36

Now lets review Flight Critical Systems of the F-22-

The F-22 Raptor was built with better reliability and maintainability than any military fighter in history. This helps ensure operational flexibility into the future. Maintainers were included early in the design process for the F-22 and they quickly established a strong foothold. To improve maintenance turnaround, the maintainers insisted on extensive self diagnostics and built-in testing capability for the various subsystems. As a result, virtually every piece of hardware in the aircraft either does its own health checks or reports when it has failed. There are more than 15,000 fault reports that can be made on the basic engine and airframe and another 15,000 fault reports available for the avionics. Most of these are low-level fault reports that do not result in warnings, cautions or advisories to the pilot or degrade the operation of the F-22. It was reasoned that if the airplane knew so much about itself, then that capability could be leveraged to help the maintainer and the pilot. This increased reliability and maintainability pays off in dollars, because it will require less manpower to fix the aircraft and consequently less airlift is required to support a deployed squadron. Additionally, reduced maintenance support provides the benefit of reduced life-cycle cost and the ability to operate more efficiently from prepared or dispersed operating locations.

Vehicle Management System (VMS)

The Vehicle Management System (VMS) provides integrated flight and propulsion control.

The VMS enables the pilot to aggressively and safely maneuver the F-22 to its maximum capabilities.

The system includes hardware, such as the control stick, throttle, rudder pedals and actuators, air data probes, accelerometers, leading edge flap drive actuators, and the primary flight control actuators. The VMS also encompasses the software that controls these devices.

The VMS will be operational when the aircraft is flown for the first time in May 1997.

The flight control software and flight control laws that underpin the VMS are tested in a specialized laboratory at LM Aero-Fort Worth, Texas.

The VMS Integration Facility, or VIF, as this lab is called, consists of an F-22 cockpit and flightworthy F-22 hardware and software. The VIF has been operational since March 1995.

Utilities and Subsystems (U&S)

The utilities and subsystems (U&S) for the F-22 includes these subsystems:

Integrated Vehicle Subsystem Controller
Environmental Control System
Fire Protection
Auxiliary Power Generation System (APGS)
Landing Gear
Fuel System
Electrical System
Hydraulics
Arresting System
Integrated Vehicle Subsystem Controller (IVSC)

The Integrated Vehicle Subsystem Controller (IVSC) is the system responsible for aircraft integration, control and diagnostics.

Environmental Control System

The F-22 uses a totally integrated environmental control system (ECS) that provides thermal conditioning throughout the flight envelope for the pilot and the avionics.

The five basic safety critical functions the ECS must take care of include: avionics cooling; adequate air to the pilot; canopy defog; cockpit pressurization; and fire protection.

Air Cycle System

The air cycle system takes bleed air from engines (which comes in to the system at between 1,200-to-2,000 degrees Fahrenheit) and cools it down in the Primary Heat Exchanger (PHX) to approximately 400 degrees. From the heat exchanger, the air is fed into the air cycle refrigeration package (ACRP). The air must be dry, so the system also includes water extractors.

The air, when it comes out of the ACRP, is now chilled to approximately 50 degrees Fahrenheit. The flight-critical equipment, the systems that are for keeping the aircraft -flying, are cooled by this air. This air is also fed into the Normalair-Garrett-built On-Board Oxygen Generating System (OBOGS) to provide breathable oxygen to the pilot, to operate the Breathing Regulator/Anti-G (BRAG) valve on the pilot's ensemble, to provide canopy defogging, and cockpit pressurization.

Liquid Cooling System

Unlike other fighter aircraft, the F-22 uses liquid cooling, rather than air cooling for the mission avionics. The F-22 is breaking ground in liquid cooling and the environment in which it works. Resistance to high temperature and durability were the driving factors in the liquid cooling design. AlliedSignal is the primary supplier of the liquid cooling equipment.

The closed-loop liquid cooling system is divided into two loops, one forward and one aft. These systems use brushless, DC current motor pumps that are connected for redundancy. Polyalphaolefin (PAO) is the medium used in the liquid cooling system.

The forward loop is for cooling the Mission Critical Avionics and keep them at a comfortable (for them) 68 degrees F. The PAO passes through the Vapor Cycle System and a filter and is routed to the Avionics and then out to the wings to cool the embedded sensors.

From there, the now-warm PAO coolant enters the aft loop, which allows it to pass by the air cycle machine, which cools that system by receiving transferred heat. The PAO then is routed to the fuel tanks, where the heat is dumped. No coolant gets mixed with the fuel however, as this is a closed-loop cooling system. The fuel in the tank is only used as a heat sink.

Thermal Management System (TMS)

The Thermal Management System (TMS) is used to keep the fuel cool. The Air Cooled Fuel Cooler (ACFC) takes air from the boundary layer diverter between the inlet and the aircraft's forward fuselage. Hot fuel passes through the heat exchanger and is colled. Greatly simplified, this is essentially blowing on hot soup to cool it down enough to eat it.

Fire Protection

Fire protection is provided for the aircraft's engine bays, the Auxiliary Power Unit (APU), and for dry bays, such as the landing gear wells, the side-of-body cavities, the Linear Linkless Ammunition Handling System (LLAHS), the On-Board Inert Gas Generation System (OBIGGS), left and right ACFCs, and ECS bay.

The aircraft uses infrared and ultraviolet sensor for fire detection and Halon 1301 for fire suppression. The Halon 1301 is the only ozone-depleting chemical on the F-22, and efforts are underway to find a replacement suppressing chemical. Space provisions have already been included for this new agent up to a chemical that requires 2.5 times the volume of the Halon.

Auxiliary Power Generation System (APGS)

The Auxiliary Power Generation System (APGS) for the F-22 is being developed, built, and tested by Allied Signal Aerospace for Boeing. The APGS consists of an auxiliary power unit (APU), and a self-contained Stored Energy System (SES).

The APGS provides secondary aircraft power for everyday main engine ground start, aircraft ground maintenance, and in-flight emergency power for aircraft recovery. The APGS uses the G-250 APU, a 450 hp turbine engine that utilizes state-of-the-art materials and design resulting in the highest power density APU in the industry (horsepower-to-weight).

Landing Gear

The F-22 utilizes tricycle landing gear, with the standard two main gears (each with a single tire) and a single-wheel, steerable nose landing gear assembly. The nose gear retracts forward, and main gear retracts outward.

The landing gear assemblies utilize AirMet 100, which provides greater strength and corrosion protection and are made by Menasco. The main gear uses a dual-piston design and are sized not to withstand a collapsed gear or flat tire landing.

The aircraft's AlliedSignal-made carbon brakes are always in anti-skid mode, which means the pilot has one less thing to remember to activate. The pilot applies pressure on the brakes by using the rudder pedals, but only after the F-22's weight-on-wheels sensor engages upon landing.

The nosewheel is a direct drive system, that is hydraulic force is applied to the nosewheel pivot to turn it. The nose gear is mechanically driven to align itself correctly before retraction.

As a safety precaution, the nosewheel clamshell doors and the lower inboard landing gear doors are physically linked to the landing gear itself. If an emergency blowdown is required, the doors will open when the gear comes down. Also, the gear down and locked indicators in the cockpit are battery operated, so if all other systems malfunction, the pilot still has a way of knowing whether his landing gear is down.

The tires on the F-22 are Michelin Air-X steel belted radials. Goodyear Bias-ply tires will also be qualified for the aircraft.

Fuel System

There are eight fuel tanks on the F-22, including one (designated F-1) in the forward fuselage behind the pilot's ejection seat. The others are located in the fuselage and the wings. The F-22 will run on JP-8, a naphthalene-based fuel with a relatively high flash point.

The F-22 has single-point ground fueling, and it can be refueled without the need for ground power. It also has a Xar-built air refueling receptacle on the top side of the aircraft in the mid fuselage directly behind the cockpit. It is covered by two butterfly doors that have integral low-voltage lights to aid in night refueling.

The F-22 also has an On-Board Inert Gas Generation System (OBIGGS) that inerts the fuel tanks as the fuel is depleted. Fuel in itself is not as explosive as the fumes are. By filling the tanks with inert nitrogen as the fuel is used, the fumes are suppressed, and the chance of explosion, such would occur if the fuel tanks were hit by gunfire, is nearly eliminated.

Electrical, Hydraulic, and Arresting Systems

The F-22 uses a Smiths Industries 270 volt, direct current (DC) electrical system. It uses two 65 kilowatt generators. The hydraulic system includes four 72 gallon-per-minute pumps and two independent 4,000 psi systems.

The F-22 has an arresting hook in an enclosed fairing between the engines on the underside of the aircraft. This hook is deployed in an emergency to stop the aircraft by means of hooking on to a wire strung out across the end of a runway. These barrier engagements work very similar to the arresting gear of an aircraft carrier.

While the F-22 has an arresting hook, it cannot land on an aircraft carrier, as the F-22 does not have the heavier structure necessary to withstand the stresses of a carrier landing. The shape of the arresting hook is not compatible with low observable design, and that is why the fairing and doors are required.

**Defcon 6** · 19 Jan 06, 21:38

Now lets review the F-22 Cockpit-

The F-22's cockpit is one of the very first "all-glass" cockpits for tactical fighters - there are no traditional round dial, standby or dedicated gauges. It accommodates the largest range of pilots (the central 99 percent of the Air Force pilot population) of any tactical aircraft. It is the first baseline "night vision goggle" compatible cockpit, and it has designed-in growth capability for helmet-mounted systems. The canopy is the largest piece of polycarbonate formed in the world with the largest Zone 1 (highest quality) optics for compatibility with helmet-mounted systems. While functionality is critical, the F-22's cockpit design also ensures pilot safety with an improved version of the proven ACES II ejection seat and a new pilot personal equipment and life support ensemble.

The F-22's cockpit represents a revolution over current "pilot offices", as it is designed to let the pilot operate as a tactician, not a sensor operator. Humans are good differentiators, but they are poor integrators. The F-22 cockpit lets the pilot do what humans do best, and it fully utilizes the power of the computer to do what it does best.

Using the power of the onboard computers, coupled with the extensive maintenance diagnostics built into the F-22 by the maintainers, that workload has been significantly reduced. The idea is to relieve pilots of the bulk of system manipulations associated with flying and allow them to do what a human does best - be a tactician.

Aircraft startup and taxi are excellent examples of harnessing the power of the computer to eliminate workload. There are only three steps to take the F-22 from cold metal and composites to full-up airplane ready for takeoff: The pilot places the battery switch 'on,' places the auxiliary power unit switch momentarily to 'start' and then places both throttles in 'idle.' The engines start sequentially right to left and the auxiliary power unit then shuts down. All subsystems and avionics are brought on line and built-in testing checks are made. Then the necessary navigation information is loaded and even the pilot's personal preferences for avionics configuration is read and the systems are tailored to those preferences. All of this happens automatically with no pilot actions other than the three steps. The airplane can be ready to taxi in less than 30 seconds after engine start.

Pilot/Vehicle Interface

The GEC-built Head-Up Display (HUD) offers a wide field of view (30 degrees horizontally by 25 degrees vertically) and serves as a primary flight instrument for the pilot. The F-22's HUD is approximately 4.5 inches tall and uses standardized symbology developed by the Air Force Instrument Flight Center. It does not present information in color, but the tactical symbol set is the same that is used on the F-22's head down displays (HDDs).

During F-22 canopy birdstrike tests, it was found that the HUD combiner glass would shatter the canopy. To solve this problem for EMD, the F-22 HUD will have a rubber buffer strip on it that will effectively shield the polycarbonate of the canopy when it flexes during a birdstrike from hitting the optical glass in the HUD and shattering. Design is also underway for a HUD that will collapse during a birdstrike, but would remain upright under all other conditions. Additionally, the team is investigating the possibility of having the HUD combiner glass laminated similar to household safety glass to preclude flying glass in the cockpit following birdstrike.

The Integrated Control Panel (ICP) is the primary means for manual pilot data entry for communications, navigation, and autopilot data. Located under the glareshield and HUD in center top of the instrument panel, this keypad entry system also has some double click functions, much like a computer mouse for rapid pilot access/use.

There are six liquid crystal display (LCD) panels in the cockpit. These present information in full color and are fully readable in direct sunlight. LCDs offer lower weight and less size than the cathode ray tube (CRT) displays used in most current aircraft. The lower power requirements also provide a reliability improvement over CRTs. The two Up-Front Displays (UFDs) measure 3"x4" in size and are located to the left and right of the ICP. The UFDs are used to display Integrated Caution/Advisory/Warning (ICAW) data, communications/navigation/identification (CNI) data and serve as the Stand-by Flight instrumentation Group and Fuel Quantity Indicator (SFG/FQI).

The Stand-by Flight Group is always in operation and, although it is presented on an LCD display, it shows the basic information (such as an artificial horizon) the pilot needs to fly the aircraft. The SFG is tied to the last source of power in the aircraft, so if everything else fails, the pilot will still be able to fly the aircraft.

The Primary Multi-Function Display (PMFD) is a 8"x8" color display that is located in the middle of the instrument panel, under the ICP. It is the pilot's principal display for aircraft navigation (including showing waypoints and route of flight) and Situation Assessment (SA) or a "God's-eye view" of the entire environment around (above, below, both sides, front and back) the aircraft.

Three Secondary Multi-Function Displays (SMFDs) are all 6.25" x 6.25" and two of them are located on either side of the PMFD on the instrument panel with the third underneath the PMFD between the pilot's knees. These are used for displaying tactical (both offensive and defensive) information as well as non-tactical information (such as checklists, subsystem status, engine thrust output, and stores management).

Integrated Caution, Advisory and Warning System (ICAW)

To reduce pilot workload in flight, the F-22 incorporates the uniquely designed integrated caution, advisory and warning system (ICAW). This system's messages normally appear on the 3-by-4 inch up-front display just below the glare shield. A total of 12 individual ICAW messages can appear at one time on the up-front display and additional ones can appear on sub pages of the display.

More than two years of detail design by pilots and engineers has gone into the filtering logic of the ICAW system and extensive testing of the system was done. In addition, the success of the Army's RAH 66 Comanche helicopter's ICAW system that uses a similar filtering approach gives the F-22 team confidence in the fundamental soundness of the design.

Two aspects of the ICAW display differentiate it from a traditional warning light panel. First, all ICAW fault messages are filtered to eliminate extraneous messages and tell the pilot specifically and succinctly what the problem is. For example, when an engine fails, the generator and hydraulic cautions normally associated with an engine being shutdown are suppressed, and the pilot is provided the specific problem in the form of an engine shutdown message.

The second is the electronic checklist. When an ICAW message occurs, the pilot depresses the checklist push button (called a bezel button) on the bottom of the UFD and the associated checklist appears on the left hand Secondary Multi-Function Display (SMFD). This function also provides access to non-emergency checklists for display to the pilot. In addition to the visual warning on the display, the aircraft has an audio system that alerts the pilot. A Caution is indicated only by the word "caution", while a Warning is announced with the specific problem - that is, "Warning. Engine Failure".

If multiple ICAWs occur, their associated checklists are selected by moving a pick box over the desired ICAW and depressing the checklist button. Associated checklists are automatically linked together so that if an engine failure occurs, the pilot will not only get the checklist for the engine failure procedure in-flight but also the single engine landing checklist. The pilot can also manually page through the checklists at any time from the main menu. This is particularly handy when helping a wing man work through an emergency.

Cockpit Display Symbology

The tactical information shown on the displays is all intuitive to the pilot-he can tell the situation around him by a glance at the screen. Enemy aircraft are shown as red triangles, friendly aircraft are green circles, unknown aircraft are shown as yellow squares, and wingmen are shown as blue F-22s. Surface-to-air missile sites are represented by pentagons (along with an indication of exactly what type missile it is) and its lethal range. In addition to shape and color, the symbols are further refined. A filled-in triangle means that the pilot has a missile firing-quality solution against the target, while an open triangle is not a firing-quality solution. The pilot has a cursor on each screen, and he can ask the aircraft's avionics system to retrieve more information. The system can determine to a 98% probability the target's type of aircraft. If the system can't make an identification to that degree, the aircraft is shown as an unknown.

Likewise, one of the original objectives for the F-22 was to increase the percentage of fighter pilots who make "kills".

The Inter/Intra Flight Data Link (IFDL) is one of the powerful tools that make all F-22s more capable. Each F-22 can be linked together to trade information without radio calls with each F-22s in a flight or between flight. Each pilot is then free to operate more autonomously because, for example, the leader can tell at a glance what his wing man's fuel state is, weapons remaining, and even the enemy aircraft targeted. Classical tactics based on visual "tally" (visual identification) and violent formation maneuvers that reduce the wing man to "hanging on" may have to be rethought in light of such capabilities.

Hands-On Throttle and Stick (HOTAS)

The F-22 features a side-stick controller (like an F-16) and two throttles that are the aircraft's primary flight controls. The GEC-built stick is located on the right console and there is a swing-out, adjustable arm rest. The stick is force sensitive and has a throw of only about one-quarter of an inch. The throttles are located on the left console. Both the stick and the throttles are high-use controls during air combat. To support pilot functional requirements, the grips include buttons and switches (that are both shape and texture coded) to control more than 60 different time-critical functions. These buttons are used for controlling the offensive (weapons targeting and release) and defensive systems (although some, like chaff and flares, can operate both automatically and manually) as well as display management.

Accommodations

Previous fighter cockpits were sized to accommodate the 5th percentile to 95th percentile pilots (a range of only 90%). The F-22 cockpit is sized to accommodate the 0.5 percentile to 99.5 percentile pilots (the body size of the central 99% of the Air Force pilot population) This represents the largest range of pilots accommodated by any tactical aircraft now in service. The rudder pedals are adjustable. The pilot has 15-degree over-the-nose visibility and excellent over-the-side and aft visibility as well.

Lighting

The cockpit interior lighting is fully Night Vision Goggle (NVG) compatible, as is the exterior lighting. The cockpit panels feature extended life, self-balancing, electroluminescent (EL) edge-lit panels with an integral life-limiting circuit that runs the lights at the correct power setting throughout their life. It starts at one-half power and gradually increases the power output to insure consistent panel light intensity over time. As a result, the cockpit always presents a well-balanced lighting system to the pilot (there is not a mottled look in the cockpit). The panels produce low amounts of heat and power and are very reliable. The aircraft also has integral position and anti-collision lights (including strobes) on the wings. The low voltage electroluminescent formation lights are located at critical positions for night flight operations on the aircraft (on the forward fuselage (both sides) under the chine, on the tip of the upper left and right wings, and on the outside of both vertical stabilizers. There are similar air refueling lights on the butterfly doors that cover the air refueling receptacle.

Life Support Ensemble

The F-22 life support system integrates all critical components of clothing, protective gear, and aircraft equipment necessary to sustain the pilot's life while flying the aircraft. In the past, these components had been designed and produced separately. The life support system components include:

An on-board oxygen generation system (OBOGS) that supplies breathable air to the pilot.
An integrated breathing regulator/anti-g valve (BRAG) that controls flow and pressure to the mask and pressure garments.
A chemical/biological/cold-water immersion (CB/CWI) protection ensemble.
An upper body counterpressure garment and a lower body anti-G garment acts a partial pressure suit at high altitudes.
An air-cooling garment, which is also going to be used by pilots on the Army's RAH-66 Comanche helicopter provides thermal relief for the pilot.
Helmet and helmet-mounted systems including C/B goggles and C/B hood; and the MBU-22/P breathing mask and hose system.
The Boeing-led life support development and its suppliers designed the life support system with the F-22's advanced performance capabilities in mind. The separate components of the life-support system must simultaneously meet pilot protection requirements established by the Air Force in the areas of higher altitude flight, acceleration, heat distress, cold water immersion, chemical and biological environments, fire, noise, and high-speed/high-altitude ejection. Escape-system tests have demonstrated that the life-support system will protect pilots when exposed to wind speeds of up to 600 knots. Current life-support systems are designed to provide protection only up to 450 knots.

The head mounted portions of the life-support system are approximately 30 percent lighter than existing systems, which improves mobility and endurance time for pilots. With its advanced design, the HGU-86/P helmet that will be used by F-22 pilots during EMD reduces the stresses on a pilot's neck by 20 percent during high-speed ejection compared to the current HGU-55/P helmets. The F-22 helmet fits more securely as the result of an ear cup tensioning device and is easily fitted to a pilot's head. The helmet provides improved passive noise protection and incorporates an Active Noise Reduction (ANR) system for superior pilot protection.

The chemical/biological/cold water immersion garment is to be worn by pilots when they fly over large bodies of cold water or into chemical/biological warfare situations. These garments meet or exceed Air Force requirements. During cold water immersion tests, the body temperature of test subjects wearing the garments fell no more than a fraction of a degree after sitting in nearly 32-degree Fahrenheit water for two hours. Current CWI suits allow body temperatures to drop below the minimum of 96.8 degrees F within an hour and a half. Normal body temperature is 98.6 degrees F. Other advantages of the F-22 life support system include its ability to fit a wider range of sizes and body shapes (the central 99% of the US Air Force pilot population).

Canopy

The F-22's canopy is approximately 140 inches long, 45 inches wide, 27 inches tall, and weighs approximately 360 pounds. It is a rotate/translate design, which means that it comes down, slides forward, and locks in place with pins. It is a much more complex piece of equipment than it would appear to be.

The F-22 canopy's transparency (made by Sierracin) features the largest piece of monolithic polycarbonate material being formed today. It has no canopy bow and offers the pilot superior optics (Zone 1 quality) throughout (not just in the area near the HUD) and it offers the requisite stealth features.

The canopy is resistant to chemical/biological and environmental agents, and has been successfully tested to withstand the impact of a four-pound bird at 350 knots. It also protects the pilot from lightning strikes.

The 3/4" polycarbonate transparency is actually made of two 3/8" thick sheets that are heated and fusion bonded (the sheets actually meld to become a single-piece article) and then drape forged. The F-16's canopy, for comparison, is made up of laminated sheets. A laminated canopy generally offers better birdstrike protection, and because of the lower altitude where the F-16 operates, this is an advantage. However, lamination also adds weight as well as reduced optics.

There is no chance of a post-ejection canopy-seat-pilot collision as the canopy (with frame) weighs slightly more on one side than the other. When the canopy is jettisoned, the weight differential is enough to make it slice nearly ninety degrees to the right as it clears the aircraft.

In testing so far, the cockpit canopy has fallen far short of its service life requirement according to DOT&E.

ACES II Ejection Seat

The F-22 uses an improved version of the ACES II (Advanced Concept Ejection Seat) ejection seat that is used in nearly every other Air Force jet combat aircraft (F-16, F-117, F-15, A-10, B-1, B-2). The seat has a center mounted (between the pilot's legs) ejection control. The F-22 version of the McDonnell Douglas-built ACES II includes several improvements over the previous seat models. These improvements include:

The addition of an active arm restraint system to eliminate arm flail injuries during high speed ejections.
An improved fast-acting seat stabilization drogue parachute system to provide increased seat stability and safety for the pilot during high-speed ejections. The drogue is located behind the pilot's head, rather than in the back of the seat and is mortar-deployed.
A new electronic seat and aircraft sequencing system that improves the timing of the various events that have to happen in order for the pilot to eject (initiation, canopy jettison, and seat catapult ignition).
A larger oxygen bottle gives the ejecting pilot more breathing air to support ejection at higher altitudes (if required).
The F-22 ACES II ejection system utilizes the standard analog three-mode seat sequencer that automatically senses the seat speed and altitude, and then selects the proper mode for optimum seat performance and safe recovery of the pilot. Mode 1 is low speed, low altitude; Mode 2 is high speed, low altitude; and Mode 3 is high altitude.

**Defcon 6** · 19 Jan 06, 21:40

And last but not least, the F-22 stealth design-

A quick look at the F-22 reveals an adherence to fundamental shaping principles of a stealthy design. The leading and trailing edges of the wing and tail have identical sweep angles (a design technique called planform alignment). The fuselage and canopy have sloping sides. The canopy seam, bay doors, and other surface interfaces are sawtoothed. The vertical tails are canted. The engine face is deeply hidden by a serpentine inlet duct and weapons are carried internally.

Advances in low-observable technologies provide significantly improved survivability and lethality against air-to-air and surface-to-air threats. The F-22's combination of reduced observability and supercruise accentuates the advantage of surprise in a tactical environment. The most publicized and most revolutionary technology for aircraft is stealth. Stealth makes an object become very difficult to detect by sensors such as radar, heat seekers (infrared), sound detectors and even the human eye. While not invisible, the F-22's radar cross section is comparable to the radar cross sections of birds and bees. Compared to other current fighters, the F-22 is much more difficult to detect.

To make a stealthy aircraft, designers had to consider five key ingredients: reducing the imprint on radar screens, ****ling noise, turning down the heat of its infrared picture, stifling radio transmissions and making the plane less visible. The leading and trailing edges of the wing and tail have identical sweep angles (a design technique called planform alignment). The fuselage and canopy have sloping sides. The canopy seam, bay doors and other surface interfaces are saw-toothed. The vertical tails are canted. The engine face is deeply hidden by a serpentine inlet duct and weapons are carried internally.

The F-22 represents a significant design evolution beyond the highly successful F-117A Nighthawk stealth fighter, with performance not achievable by today's front-line fighters. Low observable, or stealth, technology has advanced to the point where conventional aerodynamic configurations can be made incorporating low observability without compromising aerodynamic performance or increasing costs significantly. Design development risk was greatly reduced by the performance demonstrated in the dem/val program where angle of attack attitudes up to 60 degrees were flown. The validity of the low observability features of the F-22's design were confirmed by full-scale pole model testing.

Low observability is achieved by a range of measures. The F-22 employs planform shaping and faceting with blended facet boundaries, the latter a necessary concession to high performance aerodynamics. This is apparent in the shape of the nose, the fuselage sides about the inlets and engines, and the upper forward fuselage. Lockheed/B/GD used serrated edges extensively, as with the F-117A, to control the returns from panel boundaries, this is very visible on the undercarriage and weapon bay doors. The planform results in a multiple lobe design, as the boundaries of the major surfaces are not parallel with respect to each other. Planform return lobe structure is defined by the radiation pattern lobes resulting from surface wave reflections which occur at the leading and trailing edges of the airframe's major surfaces. The objective of lobing is to concentrate this unavoidable radar return into specific directions so as to minimise frontal/aft/beam aspect return and maximise scintillation in the direction of the lobe. Scintillation is a measure of how rapidly the size of the return varies with angle, the greater this variation, the more difficult a target is to track. The lower the number of lobes and the narrower the lobes, the lower the probability of detecting any return.

Radar absorbant materials, or RAM is applied sparingly on the F-22 airframe as opposed to the entire airframe on the F-117. This is because designers have incorporated curves on crucial surfaces and edges, which lessens the need for RAM. For example, new ceramic-matrix RAM is utilized on the engine exhaust nozzles to reduce radar and IR signatures, and a greater amount of wide-band structural RAM is used on the wing edges. The interesting shape of the radome on the F-22 reflects radar signals at all frequencies except the precise wavelengths emitted from the F-22. This can be attributed to the radome's low bandpass type.

To apply the complex system of paints and coatings necessary to meet the F-22's stringent radar cross section (RCS) requirements takes not only state-of-the-art equipment and hands-on technicians, but also a wide-ranging support system. A new type of paint, or topcoat, increases the F-22 Raptor's stealthiness by reducing its vulnerability to infrared threats. To meet F-22 requirements, Boeing developed the topcoat to protect the aircraft against a broad range of wavelengths. The new paint replaces conventional topcoats, performing all the required environmentally protective functions while also reducing the aircraft's vulnerability to detection. The topcoat does not add to the F-22's weight, and provides performance enhancement at a very modest cost. It is applied in a two-tone camouflage design, patterned after the F-15 "Mod-Eagle" paint scheme. Development of the new topcoat began during the early stages of the F-22 program. Since that time, a small team at Boeing in Seattle has worked to refine the paint and improve its application characteristics in a production-level environment. Technicians at Lockheed Martin painted the first few aircraft by hand, however, robotic application is planned for future Raptors, including Raptor 04, which is scheduled to fly this summer. The topcoat application for each Raptor is expected to take one to two days.

Another important feature of the F-22's stealth characteristics is the new low-RCS air data system. This system uses four ports distributed along the forward fuselage to reduce emission control (EMCON). In addition, the F-22 is the first fighter aircraft to include a completely frameless canopy. This eliminates RCS reflections from the windshield arc without compromising structural integrity.

Fundamentals of Stealth Design

Design for low observability, and specifically for low radar cross section (RCS), began almost as soon as radar was invented. The predominantly wooden deHavilland Mosquito was one of the first aircraft to be designed with this capability in mind.

Against World War II radar systems, that approach was fairly successful, but it would not be appropriate today. First, wood and, by extension, composite materials, are not transparent to radar, although they may be less reflective than metal; and second, the degree to which they are transparent merely amplifies the components that are normally hidden by the outer skin. These include engines, fuel, avionics packages, electrical and hydraulic circuits, and people.

In the late 1950s, radar absorbing materials were incorporated into the design of otherwise conventionally designed aircraft. These materials had two purposes: to reduce the aircraft cross section against specific threats, and to isolate multiple antennas on aircraft to prevent cross talk. The Lockheed U-2 reconnaissance airplane is an example in this category.

By the 1960s, sufficient analytical knowledge had disseminated into the design community that the gross effects of different shapes and components could be assessed. It was quickly realized that a flat plate at right angles to an impinging radar wave has a very large radar signal, and a cavity, similarly located, also has a large return.

Thus, the inlet and exhaust systems of a jet aircraft would be expected to be dominant contributors to radar cross section in the nose on and tail on viewing directions, and the vertical tail dominates the side on signature.

Airplanes could now be designed with appropriate shaping and materials to reduce their radar cross sections, but as good numerical design procedures were not available, it was unlikely that a completely balanced design would result In other words, there was always likely to be a component that dominated the return in a particular direction. This was the era of the Lockheed SR-71 'Blackbird'.

Ten years later, numerical methods were developed that allowed a quantitative assessment of contributions from different parts of a body. It was thus possible to design an aircraft with a balanced radar cross section and to minimize the return from dominant scatterers. This approach led to the design of the Lockheed F-117A and Northrop B-2 stealth aircraft.

Since then there has been continuous improvement in both analytical and experimental methods, particularly with respect to integration of shaping and materials. At the same time, the counter stealth faction is developing an increasing understanding of its requirements, forcing the stealth community into another round of improvements. The message is, that with all the dramatic improvements of the last two decades, there is little evidence of leveling off in capability.

Radar Cross Section Fundamentals

There are two basic approaches to passive radar cross section reduction: shaping to minimize backscatter, and coating for energy absorption and cancellation. Both of these approaches have to be used coherently in aircraft design to achieve the required low observable levels over the appropriate frequency range in the electromagnetic spectrum.

Shaping

There is a tremendous advantage to positioning surfaces so that the radar wave strikes them at close to tangential angles and far from right angles to edges, as will now be illustrated.

To a first approximation, when the diameter of a sphere is significantly larger than the radar wavelength, its radar cross section is equal to its geometric frontal area.

The return of a one-square-meter sphere is compared to that from a one-meter-square plate at different look angles. One case to consider is a rotation of the plate from normal incidence to a shallow angle, with the radar beam at right angles to a pair of edges. The other is with the radar beam at 45 degrees to the edges. The frequency is selected so that the wavelength is about 1/10 of the length of the plate, in this case very typical of acquisition radars on surface to air missile systems.

At normal incidence, the flat plate acts like a mirror, and its return is 30 decibels (dB) above (or 1,000 times) the return from the sphere. If we now rotate the plate about one edge so that the edge is always normal to the incoming wave, we find that the cross section drops by a factor of 1,000, equal to that of the sphere, when the look angle reaches 30 degrees off normal to the plate.

As the angle is increased, the locus of maxima falls by about another factor Of 50, for a total change of 50,000 from the normal look angle.

Now if you go back to the normal incidence case and rotate the plate about a diagonal relative to the incoming wave, there is a remarkable difference. In this case, the cross section drops by 30 dB when the plate is only eight degrees off normal, and drops another 40 dB by the time the plate is at a shallow angle to the incoming radar beam. This is a total change in radar cross section of 10,000,000!

From this, it would seem that it is fairly easy to decrease the radar cross section substantially by merely avoiding obviously high-return shapes and attitude angles.

However, multiple-reflection cases have not yet been looked at, which change the situation considerably. It is fairly obvious that energy aimed into a long, narrow, closed cavity, which is a perfect reflector internally, will bounce back in the general direction of its source. Furthermore, the shape of the cavity downstream of the entrance clearly does not influence this conclusion.

However, the energy reflected from a straight duct will be reflected in one or two bounces, while that from a curved duct will require four or five bounces. It can be imagined that with a little skill, the number of bounces can be increased significantly without sacrificing aerodynamic performance. For example, a cavity might be designed with a high-cross-sectional aspect ratio to maximize the length-to-height ratio. If we can attenuate the signal to some extent with each bounce, then clearly there is a significant advantage to a multi-bounce design. The SR-71 inlet follows these design practices.

However, there is a little more to the story than just the so called ray tracing approach.

When energy strikes a plate that is smooth compared to wavelength, it does not reflect totally in the optical approximation sense, i.e., the energy is not confined to a reflected wave at a complementary angle to the incoming wave.

The radiated energy, in fact, takes a pattern like a typical reflected wave structure. The width of the main forward scattered spike is proportional to the ratio of the wavelength to the dimension of the reradiating surface, as are the magnitudes of the secondary and tertiary spikes. The classical optical approximation applies when this ratio approaches zero. Thus, the backscatter - the energy radiated directly back to the transmitter increases as the wavelength goes up, or the frequency decreases.

When designing a cavity for minimum return, it is important to balance the forward scatter associated with ray tracing with the backscatter from interactions with the first surfaces. Clearly, an accurate calculation of the total energy returned to the transmitter is very complicated, and generally has to be done on a supercomputer.

Coatings and Absorbers

It is fairly clear that although surface alignment is very important for external surfaces and inlet and exhaust edges, the return from the inside of a cavity is heavily dependent on attenuating materials. It is noted that the radar-frequency range of interest covers between two and three orders of magnitude. Permeability and dielectric constant are two properties that are closely associated with the effectivity of an attenuating material. They both vary considerably with frequency in different ways for different materials. Also, for a coating to be effective, it should have a thickness that is close to a quarter wavelength at the frequency of interest.

High Temperature Coatings

Reduction of radar cross section of engine nozzles is also very important, and is complicated by high material temperatures. The electromagnetic design requirements for coatings are not different from those for low temperatures, but structural integrity is a much bigger issue.

Jet Wakes

The driver determining radar return from a jet wake is the ionization present. Return from resistive particles, such as carbon, is seldom a significant factor. It Is important in calculating the return from an ionized wake to use nonequilibrium mathematics, particularly for medium and high altitude cases.

The very strong ion density dependency on maximum gas temperature quickly leads to the conclusion that the radar return from the jet wake of an engine running in dry power is insignificant, while that from an afterburning wake could be dominant.

Component Design

When the basic aircraft signature is reduced to a very low level, detail design becomes very important. Access panel and door edges, for example, have the potential to be major contributors to radar cross section unless measures are taken to suppress them.

Based on the discussion of simple flat plates, it is clear that it is generally unsatisfactory to have a door edge at right angles to the direction of flight. This would result in a noticeable signal in a nose on aspect. Thus, conventional rectangular doors and access panels are unacceptable.

The solution is not only to sweep the panel edges, but to align those edges with other major edges on the aircraft.

The pilot's head, complete with helmet, is a major source of radar return. It is augmented by the bounce path returns associated with internal bulkheads and frame members. The solution is to design the cockpit so that its external shape conforms to good low radar cross section design rules, and then plate the glass with a film similar to that used for temperature control in commercial buildings.

Here, the requirements are more stringent: it should pass at least 85% of the visible energy and reflect essentially all of the radar energy. At the same time, a pilot would prefer not to have noticeable instrument-panel reflection during night flying.

On an unstable, fly by wire aircraft, it is extremely important to have redundant sources of aerodynamic data. These must be very accurate with respect to flow direction, and they must operate ice free at all times. Static and total pressure probes have been used, but they clearly represent compromises with stealth requirements. Several quite different techniques are in various stages of development.

On board antennas and radar systems are a major potential source of high radar visibility for two reasons. One is that it is obviously difficult to hide something that is designed to transmit with very high efficiency, so the so called in band radar cross section is liable to be significant. The other is that even if this problem is solved satisfactorily, the energy emitted by these systems can normally be readily detected. The work being done to reduce these signatures cannot be described here.

Infrared Radiation

There are two significant sources of infrared radiation from air breathing propulsion systems: hot parts and jet wakes. The fundamental variables available for reducing radiation are temperature and emissivity, and the basic tool available is line of sight masking.

Recently some interesting progress has been made in directed energy, particularly for multiple bounce situations, but that subject will not be discussed further here. Emissivity can be a double edged sword, particularly inside a duct.

While a low emissivity surface will reduce the emitted energy, it will also enhance reflected energy that may be coming from a hotter internal region. Thus, a careful optimization must be made to determine the preferred emissivity pattern inside a jet engine exhaust pipe.

This pattern must be played against the frequency range available to detectors, which typically covers a band from one to 12 microns.

The short wavelengths are particularly effective at high temperatures, while the long wavelengths are most effective at typical ambient atmospheric temperatures. The required emissivity pattern as a function of both frequency and spatial dispersion having been determined, the next issue is how to make materials that fit the bill.

The first inclination of the infrared coating designer is to throw some metal flakes into a transparent binder. Coming up with a transparent binder over the frequency range of interest is not easy, and the radar coating man probably won't like the effects of the metal particles on his favorite observable.

The next move is usually to come up with a multi layer material, where the same cancellation approach that was discussed earlier regarding radar suppressant coatings is used. The dimensions now are in angstroms rather than millimeters.

The big push at present is in moving from metal layers in the films to metal oxides for radar cross section compatibility. Getting the required performance as a function of frequency is not easy, and it is a significant feat to get down to an emissivity of 0.1, particularly over a sustained frequency range. Thus, the biggest practical ratio of emissivities is liable to be one order of magnitude.

Everyone can recognize that all of this discussion is meaningless if engines continue to deposit carbon (one of the highest emissivity materials known) on duct walls. For the infrared coating to be effective, it is not sufficient to have a very low particulate ratio in the engine exhaust, but to have one that is essentially zero.

Carbon buildup on hot engine parts is a cumulative situation, and there are very few bright, shiny parts inside exhaust nozzles after a number of hours of operation. For this reason alone, it is likely that emissivity control will predominantly be employed on surfaces other than those exposed to engine exhaust gases, i.e., inlets and aircraft external parts.

The other available variable is temperature. This, in principle, gives a great deal more opportunity for radiation reduction than emissivity, because of the large exponential dependence. The general equation for emitted radiation is that it varies with the product of emissivity and temperature to the fourth power.

However, this is a great simplification, because it does not account for the frequency shift of radiation with temperature. In the frequency range at which most simple detectors work (one to five microns), and at typical hot-metal temperatures, the exponential dependency will be typically near eight rather than four, and so at a particular frequency corresponding to a specific detector, the radiation will be proportional to the product of the emissivity and temperature to the eighth power. It is fairly clear that a small reduction in temperature can have a much greater effect than any reasonably anticipated reduction in emissivity.

The third approach is masking. This is clearly much easier to do when the majority of the power is taken off by the turbine, as in a propjet or helicopter application, than when the jet provides the basic propulsive force.

The former community has been using this approach to infrared suppression for many years, but it is only recently that the jet-propulsion crowd has tackled this problem. The Lockheed F 117A and the Northrop B 2 both use a similar approach of masking to prevent any hot parts being visible in the lower hemisphere.

In summary, infrared radiation should be tackled by a combination of temperature reduction and masking, although there is no point in doing these past the point where the hot parts are no longer the dominant terms in the radiation equation.

The main body of the airplane has its own radiation, heavily dependent on speed and altitude, and the jet plume can be a most significant factor, particularly in afterburning operation. Strong cooperation between engine and airframe manufacturers in the early stages of design is extremely important. The choice of engine bypass ratio, for example, should not be made solely on the basis of performance, but on a combination of that and survivability for maximum system effectiveness.

The jet-wake radiation follows the same laws as the engine hot parts, a very strong dependency on temperature and a multiplicative factor of emissivity. Air has a very low emissivity, carbon particles have a high broadband emissivity, and water vapor emits in very specific bands.

Infrared seekers have mixed feelings about water vapor wavelengths, because, while they help in locating jet plumes, they hinder in terms of the general attenuation due to moisture content in the atmosphere. There is no reason, however, why smart seekers shouldn't be able to make an instant decision about whether conditions are favorable for using water-vapor bands for detection.

Summary

The low signatures achieved by modern special-purpose aircraft are due to a combination of shaping, material, material selection, and careful attention to detail design. Budgeting of component signatures across a wide range of frequencies and attitude angles is mandatory. just as in a blackout, the game can be given away by one ***** of light.

**Defcon 6** · 19 Jan 06, 22:23

Really? First time i hear about this, can i get a source? Also last time i heard the congress substantantially cut the production of F-22.

Rusky is wrong once again.

The following is from www.gao.gov
GAO-01-636T Report-

In September 2001, DOD informed Congress that the F-22 production program would exceed the congressional cost limit by $5.4 billion and the Air Force would purchase a minimum of 303 aircraft, a reduction of 36 aircraft.21 The Air Force proposed an acquisition plan that extends initial low-rate production two additional years and begins high-rate production in fiscal year 2006 rather than 2004. The proposed plan is designed to provide funds for cost reduction initiatives by funding fewer aircraft in the early production years of the proposed plan. Table 5 shows the planned aircraft purchases under the prior and the proposed acquisition plans and the quantity reductions through 2005.
21The Air Force still intends to try to procure these 36 aircraft if cost savings are realized through ongoing cost savings projects.
Page 22 GAO-02-298 F-22 Aircraft

The fiscal year 2002 Defense Appropriations Act provided funds to increase initial low-rate production to 13 F-22 aircraft.22 The act also provided advance procurement funds for F-22s in fiscal year 2003. The Air Force proposes to continue low-rate initial production through 2005 and begin high-rate production of 40 aircraft in fiscal year 2006.
In several reports over the last 7 years, we concluded that DOD should minimize commitments to F-22 production until completion of operational testing. In our March 2001 report, we concluded that limiting production to no more than 10 aircraft a year (the fiscal year 2001 quantity) was a prudent way to mitigate risks until the Air Force completes operational testing.
The Air Force’s current plan would reduce the annual buy of low-rate production aircraft, but it would increase the total commitment of production aircraft before the projected completion of operational testing in December 2003. Specifically, the Air Force had planned to buy 47 aircraft at about $9.8 billion prior to the completion of operational testing in February 2003. However, under the current acquisition plan, it plans to buy 71 aircraft at about $14.9 billion prior to the completion of operational testing, now scheduled for December 2003. Moreover, should the schedule for operational testing slip further, as indicated earlier in this report, the Air Force’s commitment to a greater number of aircraft before the end of operational testing could increase significantly. Buying production articles before they can be adequately tested can result in buying systems that require significant, and sometimes costly, modifications to achieve satisfactory performance; accepting less capable systems than planned; and deploying substandard systems to combat forces. Conversely, lower
22P.L. 107-117, Jan.10, 2002.
Page 23 GAO-02-298 F-22 Aircraft 14

production rates could increase average procurement cost over the life of the program.

But you do, your mind needs to compensate for the blow this thread made to your fantansy world. You can not rebute any of the points in those articles, non.

GAO-02-298 Report-

The F-22 is an air superiority aircraft with advanced features to make it less detectable to adversaries (stealth characteristics) and capable of high speeds for long ranges.8 It has integrated avionics to greatly improve pilots’ awareness of the situation surrounding them. The objectives of the F-22 development program are to (1) design, fabricate, test, and deliver 9 F-22 development test aircraft, 2 non-flying structural test aircraft, 6 production representative test aircraft, and 37 flight-qualified engines; (2) design, fabricate, integrate, and test the avionics suite; and (3) design, develop, and test the support and training systems. The F-22 is being developed under contracts with Lockheed Martin Corporation (for the aircraft) and Pratt & Whitney Corporation (for the engine).
Following a history of increasing cost estimates to complete the development phase of the F-22 program, the National Defense Authorization Act for Fiscal Year 1998 established a cost limitation of $18.688 billion for F-22 development and a limitation of $43.4 billion for production.9 The act instructed the secretary of the air force to adjust the cost limitation for the amounts of increases or decreases in costs attributable to economic inflation after September 30, 1997, and for compliance with changes in federal, state, and local laws enacted after September 30, 1997. Congressional direction in fiscal year 2000 legislation added six production representative test aircraft to the development program, which helped increase the cost limitation to $20.443 billion.
The National Defense Authorization Act for Fiscal Year 2000 required that before the secretary of the air force awards a contract for F-22 low-rate initial production,10 the secretary of defense had to certify that the (1) test plan in the program’s development phase is adequate for determining the
8Air superiority is the degree of air dominance that allows the conduct of operations by land, sea, and air forces without prohibitive interference by the enemy.
9P.L. 105-85, Nov. 18, 1997.
10P.L. 106-65, Oct. 5, 1999.
Page 4 GAO-02-298 F-22 Aircraft
operational effectiveness and suitability of the F-22 aircraft and (2) development phase and the production phase for the F-22 program could be executed within the congressionally mandated cost limitations.11 If the Secretary of Defense was unable to make either of these certifications, he would be required to submit to the congressional defense committees a report that includes (1) the reasons the certifications could not be made, (2) a revised acquisition plan if the decision to proceed with low-rate initial production is made, and (3) revised cost estimates for the remainder of the development phase and the production phase if the decision is made to proceed with low-rate initial production.
On September 13, 2001, the under secretary of defense for acquisition, technology, and logistics notified the congressional defense committees that DOD had approved the F-22 program for low-rate initial production. The under secretary certified that the development test plan is adequate to determine the operational effectiveness and suitability of the F-22 aircraft. The under secretary said DOD could not certify that the F-22 development phase or the production phase could be completed within the existing congressional cost limitations. In his letter, he stated that both the Air Force and the Office of the Secretary of Defense estimates of the cost to complete the development phase exceeded the cost limitation. He indicated that the development phase would cost an additional $557 million. However, instead of requesting an increase in the cost limitation amount, he asked that the development cost limitation be removed. The under secretary also developed a revised acquisition plan and requested that Congress remove the production cost limitation, estimating that the production phase could cost $5.4 billion more than the $37.6 billion production cost limitation.
In December 2001, the National Defense Authorization Act for Fiscal Year 2002 eliminated the development cost limitation.12 The production cost limitation remains in effect.
11The limitation on production cost does not specify a quantity of F-22 aircraft. 12P.L. 107-107, Dec. 28, 2001.
Page 5 GAO-02-298 F-22 Aircraft

Please, refute, so far you didn't, cause you can't. And yes US senate did make all those statements.

No.

GAO-02-298 Report-

F-22 Program Meets DOD’s According to the Air Force, the F-22 program had fulfilled all test criteria Test Criteria to Continue considered prerequisites for awarding the fiscal year 2002 low-rate with Low-Rate Production production contract. The under secretary of defense for acquisition,
technology, and logistics established the criteria. The test criteria included completing specific testing of the avionics for guided missile launch, engine, and radar. DOD required the criteria to be met prior to the planned December 2001 contract award date for 13 low-rate production aircraft. (See appendix I for a listing of the criteria.)

Reread the article.

I've already disproved it. The article claimed that F-22 production was cut severely from some false number like...600+ aircraft to some equally bs number. The actual number of F-22 aircraft stands at 333 aircraft, and so far only 85 aircraft have been cut in it's TOTAL development program 1988-2005.

Yeah they don't have ground threat, the AA equipment they used was vastly outdated, they did not have any kind of a airspace control system and most of their planes never took off, and a lot of them were barried.

Well it was russian equipment. Enough said.

**lurker** · 19 Jan 06, 22:32

Operating Empty Weight 31,700 lb (14379 kg)

Please post the empty weight data for F-22

**Rusky** · 19 Jan 06, 22:34

Originally Posted by Defcon 6

Rusky is wrong once again.

The following is from www.gao.gov
GAO-01-636T Report-

In September 2001, DOD informed Congress that the F-22 production program would exceed the congressional cost limit by $5.4 billion and the Air Force would purchase a minimum of 303 aircraft, a reduction of 36 aircraft.21 The Air Force proposed an acquisition plan that extends initial low-rate production two additional years and begins high-rate production in fiscal year 2006 rather than 2004. The proposed plan is designed to provide funds for cost reduction initiatives by funding fewer aircraft in the early production years of the proposed plan. Table 5 shows the planned aircraft purchases under the prior and the proposed acquisition plans and the quantity reductions through 2005.
21The Air Force still intends to try to procure these 36 aircraft if cost savings are realized through ongoing cost savings projects.
Page 22 GAO-02-298 F-22 Aircraft

The fiscal year 2002 Defense Appropriations Act provided funds to increase initial low-rate production to 13 F-22 aircraft.22 The act also provided advance procurement funds for F-22s in fiscal year 2003. The Air Force proposes to continue low-rate initial production through 2005 and begin high-rate production of 40 aircraft in fiscal year 2006.
In several reports over the last 7 years, we concluded that DOD should minimize commitments to F-22 production until completion of operational testing. In our March 2001 report, we concluded that limiting production to no more than 10 aircraft a year (the fiscal year 2001 quantity) was a prudent way to mitigate risks until the Air Force completes operational testing.
The Air Force’s current plan would reduce the annual buy of low-rate production aircraft, but it would increase the total commitment of production aircraft before the projected completion of operational testing in December 2003. Specifically, the Air Force had planned to buy 47 aircraft at about $9.8 billion prior to the completion of operational testing in February 2003. However, under the current acquisition plan, it plans to buy 71 aircraft at about $14.9 billion prior to the completion of operational testing, now scheduled for December 2003. Moreover, should the schedule for operational testing slip further, as indicated earlier in this report, the Air Force’s commitment to a greater number of aircraft before the end of operational testing could increase significantly. Buying production articles before they can be adequately tested can result in buying systems that require significant, and sometimes costly, modifications to achieve satisfactory performance; accepting less capable systems than planned; and deploying substandard systems to combat forces. Conversely, lower
22P.L. 107-117, Jan.10, 2002.
Page 23 GAO-02-298 F-22 Aircraft 14

production rates could increase average procurement cost over the life of the program.

GAO-02-298 Report-

The F-22 is an air superiority aircraft with advanced features to make it less detectable to adversaries (stealth characteristics) and capable of high speeds for long ranges.8 It has integrated avionics to greatly improve pilots’ awareness of the situation surrounding them. The objectives of the F-22 development program are to (1) design, fabricate, test, and deliver 9 F-22 development test aircraft, 2 non-flying structural test aircraft, 6 production representative test aircraft, and 37 flight-qualified engines; (2) design, fabricate, integrate, and test the avionics suite; and (3) design, develop, and test the support and training systems. The F-22 is being developed under contracts with Lockheed Martin Corporation (for the aircraft) and Pratt & Whitney Corporation (for the engine).
Following a history of increasing cost estimates to complete the development phase of the F-22 program, the National Defense Authorization Act for Fiscal Year 1998 established a cost limitation of $18.688 billion for F-22 development and a limitation of $43.4 billion for production.9 The act instructed the secretary of the air force to adjust the cost limitation for the amounts of increases or decreases in costs attributable to economic inflation after September 30, 1997, and for compliance with changes in federal, state, and local laws enacted after September 30, 1997. Congressional direction in fiscal year 2000 legislation added six production representative test aircraft to the development program, which helped increase the cost limitation to $20.443 billion.
The National Defense Authorization Act for Fiscal Year 2000 required that before the secretary of the air force awards a contract for F-22 low-rate initial production,10 the secretary of defense had to certify that the (1) test plan in the program’s development phase is adequate for determining the
8Air superiority is the degree of air dominance that allows the conduct of operations by land, sea, and air forces without prohibitive interference by the enemy.
9P.L. 105-85, Nov. 18, 1997.
10P.L. 106-65, Oct. 5, 1999.
Page 4 GAO-02-298 F-22 Aircraft
operational effectiveness and suitability of the F-22 aircraft and (2) development phase and the production phase for the F-22 program could be executed within the congressionally mandated cost limitations.11 If the Secretary of Defense was unable to make either of these certifications, he would be required to submit to the congressional defense committees a report that includes (1) the reasons the certifications could not be made, (2) a revised acquisition plan if the decision to proceed with low-rate initial production is made, and (3) revised cost estimates for the remainder of the development phase and the production phase if the decision is made to proceed with low-rate initial production.
On September 13, 2001, the under secretary of defense for acquisition, technology, and logistics notified the congressional defense committees that DOD had approved the F-22 program for low-rate initial production. The under secretary certified that the development test plan is adequate to determine the operational effectiveness and suitability of the F-22 aircraft. The under secretary said DOD could not certify that the F-22 development phase or the production phase could be completed within the existing congressional cost limitations. In his letter, he stated that both the Air Force and the Office of the Secretary of Defense estimates of the cost to complete the development phase exceeded the cost limitation. He indicated that the development phase would cost an additional $557 million. However, instead of requesting an increase in the cost limitation amount, he asked that the development cost limitation be removed. The under secretary also developed a revised acquisition plan and requested that Congress remove the production cost limitation, estimating that the production phase could cost $5.4 billion more than the $37.6 billion production cost limitation.
In December 2001, the National Defense Authorization Act for Fiscal Year 2002 eliminated the development cost limitation.12 The production cost limitation remains in effect.
11The limitation on production cost does not specify a quantity of F-22 aircraft. 12P.L. 107-107, Dec. 28, 2001.
Page 5 GAO-02-298 F-22 Aircraft

How does any of this disproove anything said in that article about the fact that F-22 can infact be seen by radar and has plenty of bugs? As well as its use of primitive microchips back in 2000.

No.

GAO-02-298 Report-

F-22 Program Meets DOD’s According to the Air Force, the F-22 program had fulfilled all test criteria Test Criteria to Continue considered prerequisites for awarding the fiscal year 2002 low-rate with Low-Rate Production production contract. The under secretary of defense for acquisition,
technology, and logistics established the criteria. The test criteria included completing specific testing of the avionics for guided missile launch, engine, and radar. DOD required the criteria to be met prior to the planned December 2001 contract award date for 13 low-rate production aircraft. (See appendix I for a listing of the criteria.)

This is unrelated to anything. Yes those statements i made were stated by the Senate.

I've already disproved it. The article claimed that F-22 production was cut severely from some false number like...600+ aircraft to some equally bs number. The actual number of F-22 aircraft stands at 333 aircraft, and so far only 85 aircraft have been cut in it's TOTAL development program 1988-2005.

You have disprooved nothing about the stealth capabilities of F-22 my article talked about.

Well it was russian equipment. Enough said.

It was outdated, it was given to them in the 80s and 70s and even then it was not made just for them. Today's Russian PVO equipment can shoot any modern aircraft out of the sky at 3 times the range of the best US system.

**The_Burning_Kid** · 19 Jan 06, 22:37

Originally Posted by lurker

Please post the empty weight data for F-22

Empty Weight is around 18,000 kg.

**Rusky** · 19 Jan 06, 22:39

I am gonna take some time to read all the stuff you posted on the last page but from a quick glance non of it disprooves anything said in my article. Basically you posted the write up of the plane in detail, do you want applause? What is so special about that? I can post a 3 post write up of SU-34, throwing random data at the argument because you can't address a specific point (the counter stealth, which was prooven to work then that F-117 was shot down in ex-Yugoslavia) does not make you right, at all. Infact from what i gathered from reading your article on stealth, the whole concept has its flaws.

But hey thanks for the info on F-22, i was looking for something this complete for a while now. Can i get a source?

Thread: F-22, stuff you should know

LinkBack

Thread Tools

Display

Thread Information

Users Browsing this Thread

Similar Threads

Stuff that'll make you laugh!

Your Thoughts on David Icke?

The Stuff of Life

Soviet guns in Afghanistan (interview)

Whatever This Guys Is "high" On, Its Good Stuff!

Share this thread with friends:

Share this thread with friends:

Posting Permissions