S&J wrote in Wed Feb 10, 2021 3:53 pm:Watch the series
Absolutely do watch the series. It is one of the best introductions to helicopter physics. And less than an hour in total to watch.
S&J wrote in Wed Feb 10, 2021 3:53 pm:Watch the series
amue wrote in Wed Feb 10, 2021 7:46 am:Assuming the following situation:
I'm in a hover (so all blades are equal advancing) and I push the cyclic forward and I don't touch the collective and pedals, then there shouldn't be any change in applied torque. And even if the applied torque changed, torque changes should only create a yaw tendency not a roll tendency. Where does the roll tendency, I see in the FDM model, should come from?
S&J wrote in Wed Feb 10, 2021 8:06 pm:there's no advancing and retreating blade in a static hover
The rotor system is not a gyro...
Both a gyro and a rotor are circular systems and respond to applied forces somewhat similarly, but through completely separate mechanisms. However, numerous writings and pilots use the terms interchangebly even though they are not the same thing.
Johan G wrote in Wed Feb 10, 2021 7:50 pm: While this will cause a pitch moment lowering the nose it will also raise the tail rotor higher above the center of gravity, in effect extending the vertical moment arm between the center of gravity and the tail rotor hub, and increase the roll moment of the tail rotor.
S&J wrote in Wed Feb 10, 2021 8:55 pm:Oh well that's proof then.
S&J wrote in Wed Feb 10, 2021 9:49 pm:Sarcasm
amue wrote in Wed Feb 10, 2021 9:39 pm:No. Roll, pitch and yaw are defined in reference to body fixed axes. And the vertical arm between cog and tail rotor doesn't change in the body fixed system, regardless of the aircrafts attitude.
S&J wrote in Thu Feb 11, 2021 9:56 am:So the reason it rolls is because with a sudden rotation of a nose downwards the rotor acts like a gyroscope and rotates the vehicle to the left.
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