Can Helicopters fligh inverted (sustained)

[Twin 1]

Please see,

Non-Airline forums - Rotorheads

Cheers!

[cwatters]

Radio control model helicopters can. Not sure about full size ones.

[cwatters]

Try this aero in your full size heli.... reverse slow rolling horizontal circles... Start flying backwards around a circle and then start rolling. First circle you do 4 rolls, then 3, 2 ,1 Note these are SLOW rolls so for the last circle the roll takes the whole circle to complete.

Can't do it myself but I saw a model Heli fly it at a show in windy weather. Astonishing to think of the co-ordination required.

[747FOCAL]

There is one military helicopter that can get inverted, but I do not know how long it can stay that way.

[411A]

Lockheed built it..I believe.:cool:

[GlueBall]

Saw French Helicopter team at Paris air show do multiple consecutive loops simultaneously. :cool:

[Denti]

I just saw at the ILA in Berlin the Tiger helicopter do some consecutive loops, starting with a loop out of stationary hover, quite impressive. He did a normal roll during level flight as well. The german army demonstrated a loop in the Bo 105, but i seem to remember they did that some 10 years ago for the first time.

Denti

[turbine trip]

I believe most helicopters that use 'rigid rotor' systems (e.g. BO-105, Lynx, Lockheed YAH-56 Cheyenne, etc) are capable of these types of maneuvers (loop, roll, Immelmann) and can sustain small amounts (less than 1) negative 'g' for brief periods of time.

However, I don't know of a helicopter that can sustain inverted flight, as even for the rigid rotor systems the negative 'g's would be too great. Correct me if I'm wrong....

:cool:

[M.Mouse]

I thought that they were dangerous just flying the right way up.

:D :D :D :D :D :D

[ft]

I'm pretty sure that the rotor shaft bearings wouldn't enjoy the experience. :)

Cheers,
Fred

[ShyTorque]

Many helicopters can get inverted - just once.

Some surprisingly large beasties WILL do it but the critical part is to maintain positive disc loading at all times, as in the main helicopters cannot tolerate negative G.

[Fr O'Blivien]

Twin, the answer to you question os a resoundig"No!"

All posts above relate only to models (!) and to transient manoeuvres in the real thing.

No real helicopter has ever been built to sustain negative g - inverted flight. Why would it want to?

[compressor stall]

Grass cutting?:confused:

[SK]

Here is the Tiger helicopter doing some loops during the 2001 Le Bourget show in Paris:
Tiger aerobatics mpeg (http://mantinades.k.m6.net/flightsim/Files/video/tiger.wmv)
It is quoted from the http://www.videolife.info/ webpage and its size is 645 Kb.