When helicopters run out of fuel...

It will glide down like a plane can still glide without engines (albeit a bit quick). The blades will still spin to slow down the fall.
 
From what I remember from playing ummm some Apache flight simulator on my amiga many moons ago - it mentioned autorotation

http://en.wikipedia.org/wiki/Autorotation

Autorotations are used in helicopters to perform power off landings from altitude in the event of an engine failure. During an autorotation, the main rotor is not driven by a power plant but by air flowing through the rotor disc bottom-up (imagine a windmill) while the aircraft is descending rapidly. The power required to keep the rotor spinning is obtained from the aircraft's potential and kinetic energy. An important contributing factor is the rotor's inertia.

Autorotation is also used in autogyro aircraft as the main means of achieving lift during normal operation. See autogyro for more information.
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You can test this theroy out with some paper anyway.

1 strip of paper, like 4 inches long an 1 inch wide
Cut down the middle to half way
hold with a slight angle
drop from air

Now watch it spin because of the air going through it.
 
If you think about it, as it falls the air will rush up and spin the rotors (obviously helped if the rotors are disengaged from the engine/gearbox) - it'll get to a terminal velocity of some kind the blades will be spinning pretty quickly - maybe not enough to generate sufficient lift, but it'll cause enough of a drag coefficient to slow the progress to terra firma somewhat, although the landing won't be soft, it'll be surviveable. There's plenty of documentation available of helicopter "crashes" being no more than a very rough landing.
 
some choppers can fly for quite a few minutes without having the engine turned on. takes one skilled pilot though, wouldnt like to practice it ;)
 
andy8271 said:
well this thread has doubled my fear of helicopters :p
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That's why I like to jump out of 'em! :p

I'll be taking the helicopter shuttle from Nice Airport to Monaco on Wednesday - so if you don't see me post then you'll know what's happened :p
 
Cheers guys, new i was right. I hate the old trick "well prove it". That's where you lot come in handy!

I tried wikipedia and google, but not really knowing what i was looking for it was hard to find any real evidence. I didn't know it was called "autorotation".


/Victorious
 
As someone with a degree in aerospace engineering who works for one of the aerospace companies making V22 Osprey tiltrotor, Westland Lynx and EH101 components and an RC helicopter pilot for 10 years+, I say that the helicopter has no trouble landing if the engine stops, either hovering or with forward velocity :p
 
Guybrush said:
As someone with a degree in aerospace engineering who works for one of the aerospace companies making V22 Osprey tiltrotor, Westland Lynx and EH101 components and an RC helicopter pilot for 10 years+, I say that the helicopter has no trouble landing if the engine stops, either hovering or with forward velocity :p
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It can hover without engines?????????? :confused:
 
To enter the autorotation, the pilot lowers collective all the way down, simultaneously adding right pedal (in American helicopters - the rest of the world's helicopter blades turn in the opposite direction, so you would add left pedal in them).
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Lol....anything which potentially reduces the ammount (one M or two?) of Americans in the world gets a thumbs up in my book. :p

That aside....why do Americans have to be "special"?
 
LeperousDust said:
Right here your totally random question for the day:

When a helicopter runs out of fuel, does it:
a) drop like a rock
b) descend slowishly

Answers on a postcard, and can i have credible sources backing up which ever answer you think is correct.

I'm having a little argument with someone, and would just like someone to back me up, and some proof.
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Hmmm, do you know the helicopter can lands anywhere? ;)
 
Guybrush said:
No, I never said that did I - it can land from a hover if the engine stops.
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It can land, just not very well. I've had a few lessons in helicopters and have performed a few autorotations. On loss of power, the collective is dropped to reduce the angle of attack of the rotors in order to keep them spinning for longer. As a result you drop like a stone until ~50-70ft when you pull the collective up hard, converting all the 'spinning' energy in the rotors into lift in order to smooth out your descent. It's easier said than done and I don't fancy my chances in a single engine helicopter if the engine decides to give up. :)

At least with fixed wing you have a very good chance of coming out of an engine failure without a compressed spine, or alive for that matter :p
 
An autorotating propellor has the same drag as a flat plate of the same diameter, so the drag that causes just slows the descent.
 
1pudding1 said:
An autorotating propellor has the same drag as a flat plate of the same diameter, so the drag that causes just slows the descent.
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You still go down considerably fast, it's been a while since I did it but I recall dropping at well over 2000fpm (depending on the aircraft of course). Believe me it isn't a gentle glide down like in a fixed wing aircraft, you drop like a stone and you're not left with very many options (especially when you're flying along at 1500ft! :p )
 
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