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-   -   Why do military helicopters crash rather than autorotate? (https://www.pprune.org/rotorheads/445259-why-do-military-helicopters-crash-rather-than-autorotate.html)

topendtorque 11th Mar 2011 23:46


And the sound is usually from a Bell 47
really good to hear that something of intrinsic value and quality is being preserved.
tet

wickednorthernwitch 12th Mar 2011 11:38

ifresh21

In the "movies" made in Hollywood about WW2 they would have you believe that the Americans won the war single handedly without any help from the allies.

Shame they didn't do the same in Iraq or Afghanistan and saved a lot of British lives.

Lonewolf_50 12th Mar 2011 13:45

ifresh21, have you stopped beating your wife? (That is a rhetorical question, used to make a point).

Why do military helicopters crash rather than autorotate?

What you did was assume an answer in the phrasing of your question. Some people call this "begging the question," but let's just call it ignorance at work.

On the basis of what evidence do you frame your question?

Here is another way to ask that question.

Do military helicopters crash rather than autorotate?

That is another very ignorant question.

You can autorotate and still end up at the bottom with a difficult landing that results in a crash. This happened to a colleague of mine whose tail rotor quit in a Navy SH-60B.

You can also be over terrain that works against you. You can also cock up the flare and landing. Lots of things can go wrong during a forced autorotation, particularly one involving the loss of tail rotor function.

The other problem with your question would be ...

Are the operating environments identical, or similar enough to make a comparison? This has been addressed by a number of responses to you.

Based on what you have posted, you have neither the background, nor the actual intellectual capacity, nor the curiosity, to explore the question in any depth.

You have a movie made in Hollywood. (?????????????)

WTF?

Do you actually fly helicopters?

grumpytroll 12th Mar 2011 14:16

where is this written?
 
"Besides which, military rotorcraft no longer crash: they only suffer 'hard landings.' Which probably reassures Joe Public and the beancounters more than the grunts in the back."

I would love to know the actual source of the above statement. I googled this apache crash and other crashes and found dozens of articles all of which refer to specific incidents and quote from official sources and they all use the term "crash" to describe what happened. I'm certainly willing to be educated. As far as i know the term "hard landing" has specific descriptors to describe an event but not the final outcome. ie. "the aircraft experienced a hard landing which led to the crash." Sometimes a hard landing results only in damage to the landing gear. I wouldn't consider it a crash. Or would you want to describe a fender bender in the parking lot at your local grocery as a crash?

GO

ironchefflay 12th Mar 2011 15:43

the curse of PPrune strikes again!!

rotornut 13th Mar 2011 15:42


really good to hear that something of intrinsic value and quality is being preserved
Right on. I asked a film guy why they often used the sound of a Bell 47 even on turbine helicopters. His answer: Because of the great sound!

alouette3 14th Mar 2011 17:15

I have an ongoing bet with my better half. Every time a helicopter shows up in a movie billed as a thriller, I bet that it is going to crash and burn within the next few frames.
A prime example would be ' Broken Arrow'.Several good and decent helicopters were harmed unnecessarily in the making of that movie.
I have yet to lose my bet.
Alt3

Gomer Pylot 14th Mar 2011 17:57

More likely, several good and decent helicopter models were harmed in the movie. Models don't cost nearly as much as real helicopters, and to the average movie-goer look identical. Scale is everything.

Lonewolf_50 14th Mar 2011 19:29

If I remember the story correctly, Vic Morrow was hit by a real Huey during the filming of "Twilight Zone" movie and it killed him.

:(

Not sure if that is a "crash" and I don't think it was an autorotation, but that's a Class A mishap however you slice it.

tucumseh 16th Mar 2011 17:06

The "fact" that military helicopters autorotate and "glide" to a graceful landing upon double engine failure at any altitude was one of MoD's key defences in the Chinook Mull of Kintyre case. It was the reason given why they ignored their own regulations regarding certification of Safety Critical Software for FADEC.

Ian Corrigible 21st Feb 2013 14:57

Another 'hard landing,' experienced by a USMC CH-46E participating in the Cobra Gold exercise in Thailand. Seven injured but thankfully no fatalities.

http://i.imgur.com/I5hWpOw.jpg

I/C

Um... lifting... 21st Feb 2013 15:34

S-92 video of certification autos. These guys had the advantages of:
*A hard-surfaced runway
*Test pilots
*Pre-briefing and controlled entry
*Nobody shooting at them
*A perfectly sound machine
and probably others

And it still isn't all that pretty when you get right down to it.

Autorotation of a heavy helicopter is no day at the beach.


Dennis Kenyon 21st Feb 2013 16:09

T/R crash
 
Just a short note ref Hollywood and featured helicopters ... in 2001 I flew one of the MD500s (littlebirds) for a short while while making Scott Free's production of Black Hawk Down.

It probably isn't generally known that the number one story ship pilot on that shoot in Morocco was the super American film pilot Bob Zee. (can't pronounce his full name!) While holding a 175 feet hover above Bob's MD500 below with the camera ship filming above us both, a group of local kids brought in a large catapult made up from a strip of car inner tube. They managed to launch a piece of rock at Bob's 500 while I held station above.

The rock removed Bob's T/R assembly but being the pilot he is. Bob stuffed the heli down towards the sand and pulled off a 100% non damaging landing ... if probably a tad on the 'hard' side. With the kids rounded up I landed alongside, where an engineer borrowed my T/R so Bob could fly out and back to the film base at Sale. Then with the T/R switch repeated for me, both machines were recovered safely back to base.

More on request. Dennis Kenyon.

ericferret 21st Feb 2013 16:09

In 1975 I flew down to Illesheim near Frankfurt in a British army Gazelle. While waiting for the drivers to do whatever it is that drivers do I was offered a front seat ride in a Huey Cobra going on airtest. I made small talk with the pilot and asked about the autorotation characteristics. Ok he said here we go we've just been shot down.
At that point I spoted the difference between American and British army pilots.
British pilots had practice engine failures, Americans got shot down.

Remember Vietnam had only just finished and the Americans had real combat time. My deepest respect and thanks for the best flying day I ever had.

Mind you the German army pilot who took us for a ride in a CH53 at Soest and was clearly a frustrated Messerschmitt pilot gave it a good good run for the money and that also sticks out as a memorable day.

JohnDixson 21st Feb 2013 22:31

S-92Auto
 
Um-lifting:

It was done at max gross.

212man 21st Feb 2013 23:03

thanks John, I usually refer to that video when briefing (S92) autorotations in the simulator(s) - all of which replicate the behaviour shown quite well.

SASless 22nd Feb 2013 11:48

An account I once heard sums it up.

The fellow was flying a Huey B Model Gunship in Vietnam. He got into a losing exchange with a couple of .51 Caliber Machine Guns....took several hits that resulted in the loss of hydraulics, tail rotor control and the engine. He by necessity entered autorotation and headed for the ground aiming for a rice paddy adjacent to some houses.

He said everything was going fine despite hitting some tree tops, a power line and power pole, going through the roof and end of a house, a brick wall and it was not until he hit a rice paddy dike did he lose control.

Sometimes....it just isn't doing an EOL to a cow pasture.

Lonewolf_50 22nd Feb 2013 14:50

FWIW:
Blackhawks autorotate just fine, but there's a recommended entry altitude, and airspeed, that if you aren't within easy reach of makes the entry a bit tough, and all ensuing is a catch up game.

The original question was mostly a display of gross ignorance, given that from a high hover, you can't enter an auto, and you are in a not so nice zone of the HV diagram, particularly if you have a high gross weight.

Military helicopters do autorotate. They have to , it's in the spec.

That's the answer to the question originally posed.

Ian Corrigible 16th Apr 2013 16:11

CH-53E 'hard landing' in ROK
 
21 POB, six hospitalized. Report here.

http://a57.foxnews.com/global.fncsta...pperKorea1.JPG

I/C

minigundiplomat 17th Apr 2013 09:14

If military helicopter operations were easy - it would have been civilianised by now.

There is a crapload of difference between fully laden, hot n high, 100' above hostile territory, on NVD, whilst dodging rounds, then flying 2 VIP's to Gloucester race course.


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