MV-22 crashes in Hawaii

originally posted by: cmdrkeenkid
a reply to: _Del_

I can imagine the Osprey has a glide ratio somewhere between a brick and a... I got nothing. It's late. But you get my idea, I think.

It's pretty low. Something under 5:1.

Still less exciting than a 5000' per minute decent rate trying to autorotate and hoping you don't bleed rotor speed and trying to time the flare perfectly.

a reply to: _Del_

Yeah, I can believe it. I'm sure it's not practiced for often. It's been my experience that most autorotation accidents occur while practicing autorotations anyway.

Does the Osprey carry the belly gun in standard Marine configuration, or is this an add-on only used in certain mission roles?
I heard that there is a great deal of ammo aboard to support this weapon, and wonder if it had any factor in the hard landing.

originally posted by: cmdrkeenkid
a reply to: _Del_

Yeah, I can believe it. I'm sure it's not practiced for often. It's been my experience that most autorotation accidents occur while practicing autorotations anyway.

I'm pretty sure they still practice in the simulator, but it isn't (or at least wasn't) something that was ever planned for actual flights. Those rotors bleed speed at a ridiculous rate -- especially at anything other than full back. And the disc-loading is especially high.

In normal operation, they sell it as the "best of both worlds" comparing fixed- and rotary-wing. Engines-out, and it's easy to see the severe compromises made in the design. Still a neat bit of engineering.

originally posted by: _Del_

originally posted by: cmdrkeenkid
a reply to: _Del_

I can imagine the Osprey has a glide ratio somewhere between a brick and a... I got nothing. It's late. But you get my idea, I think.

It's pretty low. Something under 5:1.

Still less exciting than a 5000' per minute decent rate trying to autorotate and hoping you don't bleed rotor speed and trying to time the flare perfectly.

You are probably right about the descent by 5000 fpm. But I'll wager that it was vortex ring state that caused the crash. This is where the rotors are choked by turbulent air recirculated through the rotors...just my guess.

a reply to: buddah6

That's a good idea. Made me think of this video from a few years ago, detailing the crash of the Osprey in Arizona in 2000.



It does a good job explaining the vortex ring state, for those who may be unfamiliar. The informational part starts at about 1:14.

The debris field covers 50-60 feet, with a piece of the aircraft having broken off and ended up on the other side of a fence. A number of people climbed the fence, despite barb wire on top, to pull people out of the wreckage. All 21 survivors are now being reported as hospitalized.

a reply to: _Del_

Does the Osprey even glide? I shouldn't think very well...

a reply to: seagull

With enough forward velocity anything glides.

a reply to: Zaphod58

Same logic that got the F-104 in the air, wasn't it?

a reply to: cmdrkeenkid

Pretty much, yes. I love the fact that they had issues finding a top speed for that beast.

a reply to: buddah6

Sounds like you're right. They're reporting they were in hover mode and lost either power or lift.

a reply to: cmdrkeenkid

The VRS starts when a rotary wing aircraft descends rapidly into a confined area where rotorwash is ingested back through the rotor destroying lift. The best example was the Blackhawk crash on the Bin Laden raid.

The V-22 was making a simulated combat delivery with a fast arrival to a LZ surrounded by trees. This makes for perfect scenario for VRS to occur.

a reply to: Zaphod58

It should fly on one engine long enough to get to the ground safely.

a reply to: cmdrkeenkid

That's what my dad always said about that particular airplane...

It was the last plane he ever worked on before he retired from the AF.

originally posted by: seagull
a reply to: _Del_

Does the Osprey even glide? I shouldn't think very well...

I understand that the V-22 flies like a normal airplane except when in the helicopter mode. This means it can glide and autorotate. With short stubby wings with high wing loading means it probably doesn't glide well. If both engines fail in a hover, it should be able to make a soft autorotation landing.

You should be able to fly out of VRS if you have enough altitude but I'm not sure about the V-22 with two side by side rotors. One rotor may in VRS and the other isn't making the aircraft uncontrollable.

They're saying now that it's possible a fire started BEFORE the accident.

a reply to: Zaphod58

It sure would be better for the V-22 if that is indeed the case. I'm just praying for the young men still in harms way!

a reply to: charlyv

The Defensive Weapon System is a (somewhat) pop and swap add-on kit. A squadron only has a set number. I would be surprised if it was on this aircraft, since when installed it takes away from seating capacity.

originally posted by: buddah6

originally posted by: _Del_

originally posted by: cmdrkeenkid
a reply to: _Del_

I can imagine the Osprey has a glide ratio somewhere between a brick and a... I got nothing. It's late. But you get my idea, I think.

It's pretty low. Something under 5:1.

Still less exciting than a 5000' per minute decent rate trying to autorotate and hoping you don't bleed rotor speed and trying to time the flare perfectly.

You are probably right about the descent by 5000 fpm. But I'll wager that it was vortex ring state that caused the crash. This is where the rotors are choked by turbulent air recirculated through the rotors...just my guess.

That's a lot more likely than losing both engines and/or transmission in flight, yes. But we were discussing autorotation.