* Alex Romosan -- Saturday 07 August 2004 00:36:
you can clearly hear the woman say that if you lift the collective you
increase the pitch of the blades so you get more lift and you'll go
up. so it would seem that collective up means helicopter goes up.
maybe in austria they do it differently.

Chauvinist bullshit ends every discussion, thanks.

>as a matter of fact it does seem that european helicopters behave >differently from american ones. > As you increase collective pitch, you need to push the left pedal > (In American helicopters...right pedal for non-American models) to >counteract the torque you generate by increasing pitch.

Yes indeed, when looking from the top down American Helicopters rotate-counter clockwise, while European/Russian Helis rotate clockwise.

Also, NASA conducted a wind tunnel test of an autogyro configuration (rotor physics almost identical to a heli but without the ability to apply shaft power to the rotor so it can't hover.) beyond an advance ratio of 1.0 the collective-thrust relationship is reversed. To increase thrust you lower the collective, to decrease thrust your raise collective.(It's the Jenkins autogyro test, don't have the NASA report number off hand) (Advance ratio is the ratio of rotor tip speed to forward flight speed)

The reason I bring this up is that one could expect similar behavior from the CarterCopter ( www.cartercopters.com ) which is one of those examples X-Plane likes to use to show how it's software is being used in real world applications.

Finally, on the subject of rotor rotation, be aware that tail rotors also tend to rotate in different directions. In fact their are stories of tail rotors being put on the opposite side of a tail and rotated in the opposite direction after initial flight testing on several aircraft to improve vibrational and noise issues. Here their is no breakdown by nationality or even main rotor rotation direction. It's just whatever worked for that particular helicopter. (The only important part is that it thrusts in the right direction to provide the appropriate anti-torque.)

Jeff


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