Osprey Criticism

[VMFA-Blaze]

"It’s like a bad poker hand, and the Marines have been investing in it for 20 years. They might have been better if they invested in brand new helicopters."

PHILIP COYLE, a former Pentagon weapons tester, on doubts about the V-22 Osprey, a hybrid aircraft heading into combat for the first time in Iraq.

 

 

This is a quote taken this morning from the New York Times Headlines on line..

but I seriously dought if its going to affect the future of the Osprey....

 

 

~S~

 

 

Blaze

[VMFA-Blaze]

:lol:

[Shaman]

V-22: If one engine fails, you're history.

[Force_Feedback]

V-22: If one engine fails, you're history.

 

Yes, if the linking shaft to the other fails afterwards, you're toast ;)

[EscCtrl]

V-22: If one engine fails, you're history.

 

Surely whilst it's flying as a plane it would be fine? would need a lot of trim but otherwise fine, right?

[EricJ]

I've ridden in a -53 a couple times, a Blackhawk, and a Chinook. I had better rides in the Chinook and -53, but the Blackhawk I nearly puked in the second time I rode in one, and done two combat landings in a C-130 (the pucker factor really goes up at night!), so if I get a ride in a V-22 I think I'll be okay, but who knows....

 

And shermangogg, you lose one rotor (tail or main) you're just as screwed. And what IguanaKing mentioned, you lose something in a -53... yeah it wouldn't be any prettier. Matter of fact one landing the idiot pilot nearly put the tail rotor in a treeline. Idiot.

[EscCtrl]

Nope. Its going to depend on the altitude at which the failure occured of course, but if an engine goes out on the V-22 at low altitude...well...put your head between your legs and kiss your ass goodbye. This is true of almost all twin-engine aircraft in this realm, but the high lift/thrust="drag of a dead engine" on the V-22 makes it even worse. :(

 

Ah right, so it is actually slightly worse then a standard twin-prop aircraft.

 

 

As for the low altitude idea - well if you're going low enough and your engines cut out - start skidding instead :P

[Force_Feedback]

Okay, how about the gearbox linking, did they remove it from the V-22B? Was it too heavy or something? AFAIK it has great redundancy, so if one engine fails, the other automatically gets into emergency mode, and drives both rotors.

[zaelu]

How about some nice ejection seets in it? :D

 

And.. Is the failure of one engine the main cause of this plane crashes?

[EscCtrl]

How many have crashed so far? and how many have been built?

 

Haven't heard from this project in so long assumed it was cancelled - thought the same with the commanche only to find out it's seeing action soon.

[Force_Feedback]

Well, when the V-22 was still 'cool' I read endless bragging about how safe it was with the redundant gearbox linkage that runs through the wing, ok, I could google for it, but heck, don't think they changed the design that much, removing a key hover safety feature, especially after all those mishaps.

[MBot]

How? Is it through exhaust gases, or a mechanical/hydraulic link? Either way, if that engine fails due to battle damage, those other links can be pretty much assumed to be severed.

 

I remember reading the same some years ago, that there is a shaft between the two rotors that keeps both turning when one engine fails. Don't know if one engine is powerful enough to keep the Osprey airborne tough, but at least the system prevents the aircraft from falling out of the sky in the case of a engine failure.

[VMFA-Blaze]

That sounds logicial enough....

 

 

~S~

 

 

Blaze

[britgliderpilot]

MBot, those are great peace-time redundancies, but what happens when the Osprey takes battle damage? :smilewink:

 

Precisely.

 

Although you could say the same of pretty much any helicopter in the event of battle damage.

[MBot]

MBot, those are great peace-time redundancies, but what happens when the Osprey takes battle damage? :smilewink:

 

I can well imagine that small arms or MG fire can take out the engine ( which is a pretty exposed part of the V-22 ) but keep the rotor/gearbox/shaft intact. It's not that those weapons tend to take out large parts of a helicopter at once. And if you get shot at with anything bigger, you are definitely at the wrong place with a transport helicopter anyway, be it a V-22 or a UH-60. Of course every helicopter can be brought down with small arms fire, but I don't see why a V-22 should be more sensitive to damage than a similar armored conventional helicopter.

 

By the way the Chinook has a similar rotor system as the V-22 in regards to the shaft ( two engines drive two shaft-connected rotors ) that is well proven.

 

 

On a side note, what is the operations concept of the Osprey? Is it intended as a combat transporter like the Huey or Blackhawk or would it rather fly on the safe side? I know for example that swiss Super Pumas would ferry around troops but not actually drop troops into combat.

[GGTharos]

I believe that the cross-link has been tested in autorotation sistuations - I guess it really dependon the altitude you have when you take damage, just like in helis ... theoretically if you were high enough to you transition to level flight and get outta there prop-plane style, then try to land somewhere heli-style, though I wonder if the transition is deemed too dangerous to attempt in case of battle damage.

[MBot]

Because the engines on a helicopter are indirectly linked to the device providing lift/thrust, through the transmission. They have two engines for a reason...for redundancy in battle. Yet, those engines indirectly drive the sole system meant to keep that aircraft in the air and under control. A severely wounded 53 or 60 can limp back to base on one engine. With the Osprey, its different, those engines are DIRECTLY responsible, for the Osprey's lift, pitch, roll, and yaw stablity.

 

I think not. A Osprey can take a hit in the engine and still limp home ( if it is light enough, or do a powered emergency landing otherwise ) because one engine can drive both rotors trough the shaft. Of course it is screwed if one engine plus the rotor connection shaft get hit. But the same also applies for the Chinook or Sea Knight. In that regard the Osprey is even safer, as when a Chinook looses the rotor connection it is screwed, while a Osprey could still fly in that situation ( each engine drives his own rotor ).

[MBot]

I was actually thinking about a pure hover. If the Osprey looses an engine, it will not behave different than any other twin engined helicopter ( limp home or ditch if too heavy ). If it looses an engine plus the rotor link, it will behave like the Chinook or Sea Knight in that situation ( =screwed ).

 

Or are you talking about the rotor/engine tilt mechanism? Because there I agree, this wont exactly increase the survivability of the Osprey. I doubt you would risk to tilt the rotors if you have taken damage in that region. If you were hit while on the hover I would fly the Osprey as a pure helicopter from then on.

[Force_Feedback]

Will it? I mean it has FADEC, engine management, the moment the computer senses a dead or dying engine, it will boost the other one, synchronize the gearboxes, whatever else. The thing is rated to achieve positive vertical flight rate, dunno at what load, though.

Since when does the V-22B have an RCS? I thought all force differential was generated by steerable rotors. And does it really have serious armoring?

[EscCtrl]

In a conventional, twin-powered aircraft? Heh...and die a little slower!:( There is no good way to lose an engine low and slow, you either have the option of egress, or at the very least (as Chet said in Weird Science)..."You die!...She walks out of here with a severe limp!" :smilewink:

 

I was implying if you were a few feet off the ground and above a nice road :P

 

 

I recall a long time ago there was a TV show in the UK about the possibilities of fitting light aircraft (in this case a Cessna) with a parachute so that if the engine cut out the WHOLE plane including the occupants would fall down semi-safely to the ground. Never heard about it since so not sure if any prototypes got built.

[MBot]

And does it really have serious armoring?

 

No idea, but I just read that it is intended as a assault transporter for the Marines, so it better has :)

 

 

You might be right about the RCS, but how else might it get a quick method of lateral translation in flight?

 

Thats a good question.

[Force_Feedback]

Provided it has those linkages remaining to begin with. You might be right about the RCS, but how else might it get a quick method of lateral translation in flight?

 

Maybe the actuators are really quick (like TVC nozzles are) and it has some sophisticated software crunching the do's and don'ts. I remember something like the whole engine pylons moving both forward and latterally, yaw is done by pitching one rator forward, and the other back.

 

A tail rotor failure is not always a 'oh f*** we're gonna die, jump out if you can!' situation, provided the chopper has enough forward speed, it can safely make it back home without a tail rotor. Yes the landing will be slightly problematic, but the chances are big that at least the crew can walk off without any serious/fatal injuries.

[crusty1606687734]

At the typical stall speed of a fixed wing dragging a jammed rotor behind it? I wouldn't bet my life on that. 20 knots IAS due to a microburst was all it took in my case. The aircraft returned to service quicker than I did. Its a great natural alarm clock though. The aircraft is back in service, and it and I have a special connection. She always seems to get squawked on days that I'm having a rough go of it. Its a love/hate relationship because she could have killed me, but she also left me alive. Weird. :noexpression:

 

Were you guys on approach? At what altitude were you roughly when this

burst hit you? Run through it briefly... if you don`t mind.

[Force_Feedback]

globaldefense.com:

The V-22's propulsion system consists of dual counter rotating proprotors attached to gearboxes driven by Allison AE 1107C turboshaft engines. The engines, proprotor gearboxes (PRGB), tilt-axis gearboxes (TAGB), proprotor controls, and infrared (IR) suppressors are all housed in the rotating nacelle on the end of each wing. An interconnecting drive shaft transfers power from each nacelle to the mid-wing gearbox (MWGB). This is the heart of the tiltrotor technology.

 

http://www.globalsecurity.org/military/systems/aircraft/v-22-propulsion.htm

 

 

http://www.globalsecurity.org/military/systems/aircraft/v-22-flt-cntrl.htm

[VMFA-Blaze]

Now that's some interesting detail .. Thanks for taking the time to post this.

 

It gives a clear understanding of how it operates...

 

~S~

 

 

Blaze