V-22 Defender Strikes Back on Autorotation, Sort of

Roger Williams, the executive director and site leader at Bell Helicopter Military Aircraft Assembly Center in Amarillo, Texas, wrote the following in the Amarillo Globe News on Mark Thompson's critical TIME magazine article on the V-22 Osprey:

The Time article contends the Pentagon eliminated the autorotation requirement for the V-22. The "autorotation requirement" has in fact never changed, as it was never a specific requirement. Why? Because the Osprey is not a helicopter.

The Pentagon's list of requirements for "Survivability and Crashworthiness" from 1994 states:

"Power-off glide/autorotation: The JMVX (1994-era designation for the V-22) must be capable of a survivable emergency landing."

The current requirements document says the V-22 "must be capable of performing a survivable emergency landing with all engines inoperative (Threshold/Block A/10)." [emphasis added]

What I don't get is Williams' claim that "autorotation" was never a specific requirement, yet then he quotes from the Defense Department's 1994 list of requirements for the V-22 which explicitly states "autorotation" as a means of achieving a survivable emergency landing when the V-22 is in helicopter mode (when in plane mode, it will need to be able to glide with the power off; note that it won't be able to switch between helicopter mode to plane mode if the power is down).

CORRECTION: A reader writes that the V-22 can switch from helicopter to plane mode if the engines lose power:

The reason is that as long as the rotors are turning (and     they would keep turning), there is power to the hydraulic system -- and it     is the hydraulic system that provides the power to convert. Also, with the     rotors still turning, the electrical generators still operate, providing     electrical power to the flight control system for stability and control.

 

-- Nick Schwellenbach

Comments

[Jeff]

This former Army Aviator (980 combat hours in UH-1's and AH-1's over South Vietnam, Laos, and Cambodia) is wondering if there will be a V-22 section at Arlington for the people this ill-conceived contraption is going to kill. The V-22 sure as heck isn't a helicopter (and it appears to be a marginal transport airplane at best,) so sending it to do a helicopter's job makes no sense. The contractors and procurement wizards can re-write, ignore, and edit the specs all they want, but the V-22 will never be anything other than the flying death trap that it has demonstrated itself to be during it's "development" phase. Autorotation may be "seldom used" but when the engine(s) quit, autorotation comes in pretty handy. I'd rather go into a hot LZ in a UH-1 with a couple of good door gunners than a V-22 any day of the week. No matter how much the V-22 flies it's "cherry-picked" missions, eventually a V-22 is going to find itself going into an LZ that isn't "safe" and the AAA is going to eat it up. There's still time to junk this abortion and save some lives. Unfortunately the engineers that conceived the V-22 won't be putting their lives at risk in their creation, they'll just move on to the next boondoggle.

[Frank]

So my question to all who are defending the V-22 is this:

If this bird is ready to go into battle, why all the short-cuts, and end-runs around the certification process? Why not demonstrate it's capable before lives are on the line? Sounds to me like a lot, if not most of the criticism of the V-22 is aimed at the shoddy development and shake-down.

Right now the V-22 program sounds like a classic case of "There's never enough time to do it right the first time, but always enough time to get it right the next..." Only this SNAFU is going to put bodies in bags...

[sam]

"What I don't get is Williams' claim that "autorotation" was never a specific requirement, yet then he quotes from the Defense Department's 1994 list of requirements for the V-22 which explicitly states "autorotation" as a means of achieving a survivable emergency landing when the V-22 is in helicopter mode (when in plane mode, it will need to be able to glide with the power off;"

Actually, there's probably a typo in the article, saying '1994' and meaning '1984'. The use of 'JVMX' is the tipoff. By 1994 the plane was the V-22, but in 1984 the aircraft selection and aircraft designation hadn't been made and JVMX was teh name for the overall program.

The program requirements for what would become the V-22 did not specify a Tilt-Rotor. Someone could choose to propose an advanced helicopter . The "autorotation" referred to was if a rotorcraft was selected, since they don't "glide". The original requirement was that an emergency power-off landing be survivable, not specifying how the aircraft got to that landing. That's why the term used was ""Power-off glide/autorotation:", to cover all possibilities.

[Matt]

I love this "Retired Naval Aviator" opinion like that's some holy grail of knowledge. News break for you, there are hundreds of Naval Aviators on both side of this debate. Most of the ones in favor are actually flying it now (their life at stake) or recently retired after years of working on it. Many of the those that don't like it are crusty old "Nam era guys that can't find their ass with both hands. The grey beards are so far removed from reality that they don't warrant being taken seriously. Thanks boys, if it was up to you, we'd buy some 1950 technology Phrog and it be just like the good old days right? You'd be eating AAA and MANPADS up the ass, as you putt-putted around at 100kts, but you could auto-rotate provided you didn't desynch and die instantly and burn up on the ground. Great. Thanks for the support.

The fix-wing guys have gone through 4 generations of front line fighters but here you are supporting your rotary wing brethen's attempt to modernize with an endorsement for the same old piece of crap you flew in the 60s. Hay, thanks for weighing in. Better idea, shut up and stop doing damage to the Corps.

Survivability is a complex subject. Often times you need to sub-optimize in some areas in order to take advantage of others. No A/C has been as thoroughly tested ballistically and done so well. The IR and noise signature is non-existant relative to the CH-46. Exposure time in the zone is also much less. Pay no attention to those that assert it to be a lumbering giant. It's VN diagram performance exceeds that of the UH-60. Of course, IT"S NOT A HELICOPTER !!! so stop constantly comparing it to one.

For all things in life there is a bottom line and for THIS retired Naval Aviator, it's that I'd rather fly in harm's way today in a V-22 than in a CH-46 or any other helo. Can't give a stronger personal endorsement than where you'd risk your life.

[Jim]

Check your facts before mouthing off, wise guy. The V-22 is very capable of converting from airplane to helicopter mode and back, if needed, without engine power. The reason is that as long as the rotors are turning (and they would keep turning), there is power to the hydraulic system -- and it is the hydraulic system that provides the power to convert. Also, with the rotors still turning, the electrical generators still operate, providing electrical power to the flight control system for stability and control. We should all be glad that we had real engineers and, not idiots with nothing to do but write blogs, designing the V-22. (Of course, you also probably don't have the guts to post this one.)

[Craig]

It's not even proven that the V-22 CAN'T autorotate - maybe it will be able too, but the power regulating systems do not allow a large build-up of Nr (rotor speed) above normal range to aid in the auto. The "blue ribbon panel" has already researched this. It would take A LOT of things to go wrong for the V-22 to find itself in a perdiciment where an auto would be necessary anyways. That's the beauty of triple-redundancy. Everyone stresses how important the auto is, because helo guys practice it routinely. I don't have any figures on it, but I feel that an auto is seldom used - nice to have - but practiced and not utilized. I'm sure that in the building of events that would neccessatate an auto would already have the pilots in airplane mode for gliding - if they weren't already. I would take my chances with a V-22 on glide than a CH-46 or CH-53 in an actual auto - anyday!