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  • Stitch
    replied
    What Steve said; I'd also like to point out that countries and/or services (i.e.: Australia, Canada and the US Navy) that do long-distance missions over large, unpopulated areas (particularly oceans) tend to buy two-engine designs due to the availibility of a second engine if one goes bad. Single-engine designs are better for over-land missions where the reliability of two engines isn't so critical.

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  • SteveDaPirate
    replied
    Twin engine and single engine fighters each have their own advantages and drawbacks. Twin engine designs provide some extra redundancy should the aircraft suffer an engine failure as well as an easy method of providing high amounts of thrust on heavy fighters.

    Single engine fighters offer advantages in increased internal volume for fuel, lower maintenance requirements, and lower weight/fuel consumption.

    The utility of having a second engine is a hotly debated topic with the F-35 being a single engine design. Twin engine fighters tend to have both engines located close together along the center-line of the aircraft. This is great in case of mechanical failure leading to loss of an engine, because it prevents highly off centered thrust that could lead to the inability to control the aircraft. However it does mean that in the event the aircraft eats a missile up the tailpipe, both engines are likely to be destroyed. Similarly, having the engines adjacent to one another means that if one fails in a spectacular manner, the other may be destroyed along with it.

    Aircraft designed with fewer engines (single engine fighters/twin engine airliners) are becoming more common as jet engine design is increasingly refined and reliability is getting very good. Better jet engine design is also allowing for the production of engines with very high levels of thrust, which reduces the number required to achieve the desired amount of power.

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  • Red Team
    replied
    Originally posted by Red Team View Post
    Question: What are the differences between single and twin engine fighters? Do either have any notable design advantages over the other? What factors (performance or economics wise) decide an Air Force's preference towards one or the other?
    Bump

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  • Red Team
    replied
    Question: What are the differences between single and twin engine fighters? Do either have any notable design advantages over the other? What factors (performance or economics wise) decide an Air Force's preference towards one or the other?

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  • Stitch
    replied
    Originally posted by Alpha1 View Post
    this doesn't answer why even the F-35 has a non stealthy engine
    Also, the nozzle on the F-35B is required to rotate through 90 degrees to provide vertical thrust, so it would be extremely hard to design a stealthy nozzle that could do that. And, since the DoD is trying to have as much commonality bertween all three version of the F-35, it would be prohibitively expensive to design a different (stealthy) nozzle for the A and the C.

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  • SteveDaPirate
    replied
    Originally posted by Alpha1 View Post
    this doesn't answer why even the F-35 has a non stealthy engine
    Notice that on the F-35, the exhaust nozzle on the engine has very angular edges in a sawtooth pattern, a similar shape can be seen on the fuselage surrounding the nozzle as well. This is done specifically for LO purposes as it disperses radar energy. I will also echo what others have said in that the F-35 was primarily designed to be a flexible ground attack platform, and 360 degree stealth is less important than it is for the F-22.

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  • Stitch
    replied
    Originally posted by Gun Grape View Post
    The F-22 nozzles and their shape are part of the vectored thrust system that gives it some crazy maneuverability. None of the other planes you mentioned have Vectored Thrust.

    No need for Stealth design. Notice that the nozzles on the planes in questioned are masked by stealthy fuselage extensions.
    Yes & no; the F-22 was designed from the outset to have LO from 360 degrees. Most other designs (notably the Typhoon) are designed to have LO from a certain angle (in the Typhoons case, from head on). It is VERY difficult to design a plane with LO from all angles but, in this case, the VT nozzles actually help out; 3D nozzles are much more conducive to LO than 2D nozzles and, in the Raptor's case, actually helps out with manuevering.

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  • Gun Grape
    replied
    The F-22 nozzles and their shape are part of the vectored thrust system that gives it some crazy maneuverability. None of the other planes you mentioned have Vectored Thrust.

    No need for Stealth design. Notice that the nozzles on the planes in questioned are masked by stealthy fuselage extensions.

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  • Guest's Avatar
    Guest replied
    The F-35 has a different role than first penetration. First penetrations belong to the F-22. The F-35 is the bomb truck and bombs are anything but stealthy.

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  • Alpha1
    replied
    Originally posted by Officer of Engineers View Post
    Most obvious answer: their engines ain't up to par to use those fancy gizmos.
    this doesn't answer why even the F-35 has a non stealthy engine

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  • Guest's Avatar
    Guest replied
    Most obvious answer: their engines ain't up to par to use those fancy gizmos.

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  • Alpha1
    replied
    Can anybody explain to me why are the russians and the chineese are going for round non stealthy engine nossels on their 5th Generation jets PAK FA/ T-50 , J-31 , J20 instead of a stealthy one like F-22 Raptor's?





    and even F-35 has a round non stealthy engine nossel

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  • JA Boomer
    replied
    I was wondering today if in modern times (or the last 20 years or so) if there is any reliability advantage to having heavy military aircraft with 4 engines instead of 2. Speaking mainly about transports, tankers, and the C-135 crowd. Is it preferable to have 4 engines or does the increased maintenance and fuel continue too large of a burden. New designs are appearing with 2 engines but I am wondering if this has more to do with what the manufacturers are offering.

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  • DonBelt
    replied
    tbm3fan if you come out to Boston, check the Collings Foundation schedule to see if they are having an open house or show out in Stow. They have a very nicely preserved, airworthy TBM Avenger to look over. (along with many other things, but guessing from your user name and avatar I'd say you were a tbm fan)
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  • tbm3fan
    replied
    Originally posted by desertswo View Post
    I hope you weren't referring to the standard Navy G-1 leather one. Even if you could wear it in the cockpit, it's not insulated in any way. Mostly it's a heavy windbreaker. I'm not an aviator but I have one given to me by my CO in Constellation for a job well done. I never wore it on active duty as I wasn't qualified to, but it's kind of my standard hanging out around outside in the desert winter. It's warm enough without being suffoctating, and it hides my .45 well enough, but I wouldn't want to try to survive in a blizzard wearing it.
    Yes, those G-1s have only a synthetic lining inside. On the other hand I have a similar one, circa 1950, with a fur lining inside. Military type of manufacturers tag but haven't seen another. So?

    One of the warmest coats I have ever worn. Only you can't do jumping jacks in it and many winter days it is too warm for me. However, put on gloves plus the coat and here I come Boston.;)

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