Thread: V-22 in the news again

Originally Posted by GGTharos

The Vortex Ring condition is a pretty standard helicopter phenomenon.

So, what we have is three crashes due to poor parts/QA, for which the blame rests squarely with the manufacturer, and another which is essentially pilot error (the pilot is supposed to be trained to anticipate the VRS and avoid it - it is a KNOWN phenomenon of rotary-wing aircraft)

So then, the pilot should have done his transition at speed and altitude - the only two things that let you recover from VRS, or allow you to avoid it completely (especially speed). Helicopter pilot face THE EXACT SAME PROBLEM.

If they need to descend quickly they must have a lot of forward speed, -then- slow down and go into hover or near-hover like descent.

If I was reading it right the VRS is not as serious an issue for most helicopters as they can recover from it. The V-22 because of the way the rotors are configured supposidly cannot. If I read it right when one rotor loses lift the other rotors basiclly flips the V-22 and sends it into an unrecoverable death spiral.

In the case of helicopter VRS you simply lose lift for a moment then regain control. It apparently happens all the time in Afganistian, the concern I suppose is what happens if the V-22 operates in the thin air in A-stan.

Not quite. A vortex ring state can lead virtually any helicopter right down to the crash site! It all depends if the airframe driver can encourage the thing into something resembling forward flight in the time and space available to him. Vortex ring develops during descent under power. Some types seem to give a fairly mild ride, others most certainly don't. To add a modicum of complexity to the equation, disc loading and pressure altitude exacerbates the problem. Did somebody mention Afghanistan? Oh dear.

Originally Posted by glyn

Not quite. A vortex ring state can lead virtually any helicopter right down to the crash site! It all depends if the airframe driver can encourage the thing into something resembling forward flight in the time and space available to him. Vortex ring develops during descent under power. Some types seem to give a fairly mild ride, others most certainly don't. To add a modicum of complexity to the equation, disc loading and pressure altitude exacerbates the problem. Did somebody mention Afghanistan? Oh dear.

Anyone hear if the V-22 will be allowed to operate in Afganistian?

Seemsd that he dredged up old problems without seeing if they had been addressed.

yes they can go to Afghanistan.

The Air Force and MC are flying them every day without this "dangerous" airplane falling out of the sky.

Marines Respond to V-22 Study

http://www.cdi.org/program/document....e=../index.cfm

Our study, “V-22 Osprey: Wonder Weapon or Widow Maker,” is available by clicking here. The Marine Corps Times story, “Report Blasts Osprey Testing, Readiness” appears below.

"Report blasts Osprey testing, readiness," Marine Corps Times, Dec. 11, 2006

The V-22 Osprey is unfit for combat and needs to be scrapped altogether, according to a new report from a defense think tank.

The Center for Defense Information report, titled "V-22 Osprey: Wonder Weapon or Widow Maker? They warned us. But no one is listening," includes nearly 50 pages of text sharply criticizing the tilt rotor's combat capability and lack of testing.

"If deployed in combat, the price could be fatalities inflicted not just by enemy fire, but by flaws that were the result of omitted tests and basic design deficiencies pointed out but never addressed," wrote Lee Gaillard, a former Marine reservist who has published more than 100 articles and book reviews on defense issues and aviation.


A spokesman for the program said a majority of Gaillard's report deals with earlier versions of the Osprey that are no longer in service and the author has omitted important information about testing and modifications to the aircraft currently flying.

From all indications, the Corps has no plans to halt its Osprey program, and it is set to be operational next year. The hybrid aircraft that promises to fly faster, farther and longer is a common sight in the skies over eastern North Carolina around Marine Corps Air Station New River.

Commandant Gen. James Conway flew in one during a Nov. 29 visit to Camp Lejune and spoke highly of the aircraft.

"A couple of options, it could go aboard ship with the [Marine expeditionary unit], it could go into Al Assad [Air Base]," Conway said. "It could go elsewhere or not go, but our belief is it's a great airplane. We need to get it into the fight as soon as we can. It's going to give us an enhanced capability well beyond our legacy aircraft, the venerable CH-46."

The Corps is phasing out the third of six CH-46 Sea Knight squadrons at New River. The West Coast transition will likely begin around late 2009 or early 2010, followed by overseas squadrons. There are six squadrons on the West Coast and two on Okinawa, Japan.

But Gaillard wrote that the Marine Corps should replace the Osprey with modern helicopters, which he claims would be safer and cheaper. He suggests three options:

* Augusta Westland's US101 (EH-101), which has three engines, a single rotor and was recently selected as the presidential transport helicopter.

* Boeing's CH-47F Chinook, which has two engines, two rotors and carries up to 33 combat-equipped troops.

* Sikorsky's H-92 Superhawk, which has two engines, a single rotor and carries up to 22 combat-equipped troops.

Vortex-ring state

One reason he suggests the Corps turn to one of these aircraft instead of the Osprey is because of the aerodynamic phenomenon known as vortex-ring state. This condition is caused when a helicopter descends too rapidly without enough forward air speed, putting the helicopter in its own rotor wash.

"This is the primary reason why the maximum vertical descent speed of 800 feet per minute -- that's just 9.1 mph -- is mandated for this aircraft," Gaillard wrote. "It is so slow it will make the V-22 an easy target."

Osprey pilots landing in a hot zone may try to descend more quickly and encounter vortex-ring state, he said.

That's not so, said James Darcy, spokesman for the V-22 Joint Program Office for Corps and Navy aircraft acquisition and testing.

"The V-22 is less vulnerable to VRS than any other helicopter," he said.

Extensive testing following an April 2000 Osprey crash in Marana, Ariz., the third of four crashes since 1991, which killed all 19 Marines onboard, has proven the tilt rotor can descend faster than 800 feet per minute without going into vortex-ring state, Darcy said.

"We don't see the initial onset of VRS until at least 1,600 feet per minute," he said.

Testing, most of which was conducted in 2002, also proved that pilots can get out of VRS by rotating the nacelles slightly forward. Since then, the Osprey has been modified with a safety feature no other helicopter has -- a descent rate warning system in the cockpit.

"That sounds good, but it makes no mention of the altitude at which those recovery exercises were run, where the nacelle would be able to tilt forward 16 degrees over a 2-second period, resulting in probably abort of any descent profile in progress," Gaillard wrote.

He criticizes other tests, including one engine operative testing. During 17 years of evaluation, he wrote, the V-22 has never been tested to take off or land with one engine shut down. That's the kind of landing or takeoff a pilot would need to make from a small clearing or on a mountainside, Gaillard wrote.

"Basically, he's refuting a claim that nobody's making," Darcy said. "To my knowledge, at the program office level, we certainly never had a request to further explore a single-engine takeoff issue. It comes down to a question of who gets to decide whether there's been adequate testing. The users have the final say in whether or not this aircraft is ready to be fielded."

Sounds like someone in uniform is trying a whitewash job, gunnut.
James Darcy states "Never had a request to further explore a single engined take off issue" and some readers may think that reasonable. I don't. What happens when an Osprey loses or has to shut down one engine in flight? It has never been tried, and that is the big worry I have. How is it going to land? It has to be in the rotors up mode as it cannot land like a conventional aircraft. Never been done on one engine. Why not? One day some poor user is going to lose an engine - and then he is supposed to become an instant test pilot under less than ideal conditions? No machine should be released to service until it has been thoroughly tested. Back to square one, the V-22 Osprey has not been matched to the milestone requirements, and all we hear is confusion and procrastination. The answer is simple - test the bloody thing fully, get the best brains behind it and sort the problems out. If they cannot be solved , ditch the program without further delay.

Originally Posted by glyn

Sounds like someone in uniform is trying a whitewash job, gunnut.
James Darcy states "Never had a request to further explore a single engined take off issue" and some readers may think that reasonable. I don't. What happens when an Osprey loses or has to shut down one engine in flight? It has never been tried, and that is the big worry I have. How is it going to land? It has to be in the rotors up mode as it cannot land like a conventional aircraft. Never been done on one engine. Why not? One day some poor user is going to lose an engine - and then he is supposed to become an instant test pilot under less than ideal conditions? No machine should be released to service until it has been thoroughly tested. Back to square one, the V-22 Osprey has not been matched to the milestone requirements, and all we hear is confusion and procrastination. The answer is simple - test the bloody thing fully, get the best brains behind it and sort the problems out. If they cannot be solved , ditch the program without further delay.

Ospreys HAVE BEEN TESTED for single engine failure in flight. And have done single engine landings

Lee Gaillard slips in "to take off" and then says that it hasn't been tested.

This is a false statement. "The V-22 has never been tested to land with one engine shut down. "

This is a true statement:"The V-22 has never been tested to take off or land with one engine shut down. "

The Osprey has met or exceeded all KPP and milestone requirements. Its been certified not only by the DoD, Don but also by a MIT panel.

I do love how he puts forth "defects" that are his own. The V-22 was tested to 14.5mm and he complains that it wasn't tested against "RPG"s.
I know a fer APCs that would fail that test. WOuld he like to test his replacement choices against RPGs? Or would that become a nonissue.

He also talks about the vunerable descent rate that the V-22 must fly by. 800 FPM. Oh my God, thats so slow that they will be hanging in the air just waiting to be shot down.

Oh did he mention the maximum descent rate, in the same environment (low forward speed), of the CH-46 and CH-53? Well no. FYI they are able to swoop down at the blistering speed of 460 FPM.

Guess this is the airborne version of the Stryker. Oh wait, that seemed to work pretty good vice being the rolling death trap it was suppose to be.