To: NickLappos
Picture this. The Bell and the Robinson control inputs are the same in that the swashplate will move in the same direction as cyclic input. On the Bell when the rotor is laterally disposed the pitch horn is over the longitudinal centerline of the helicopter so the advancing blade has the lower pitch and the retreating blade has the higher pitch. This is because the pitch horn leads the blade by 90-degrees.
On the Robinson when the blades are laterally disposed the pitch horn has not reached the maximum travel relative to the swashplate displacement. In fact the blade must travel an additional 18-degrees before the blades have maximum input +/-. As the blade travels from the laterally disposed position to the point where the pitch horn has maximum input the blade is changing pitch. Minus for the advancing blade and plus for the advancing blade. The blades do not have maximum input until the blades are disposed 18-degrees ahead of the mast (advancing) and 18-degree behind the mast (retreating).
Getting back to the slight change in pitch between the laterally disposed position and the point where the pitch horn is at its’ maximum displacement the blade is flapping down towards the nose because the pitch horn is following the swashplate tilt. However the blade does not reach its’ maximum pitch change until the blade is 18-degrees ahead of the mast (see above) which means if you subscribe to the phase angle theory the blade will reach its’ maximum displacement in 72-degrees so that it is full down flap over the nose. However if you subscribe to the precession theory (Aerodynamic/Gyroscopic) the blade will have maximum down flap 18-degrees past dead center.
If the blade flap takes place within the 72-degree phase angle please describe the disc plane relative to the horizon.
Please use language that stupid people like me can understand.