User manual

DodoSim 206 FSX User Manual

Page 36

Important note: Effect of “General Realism” slider on flight behaviours:

The “General Realism” slider in FSX’s “Aircraft->Realism Settings” dialog can be used to scale the

magnitude of all flight dynamics behaviours such as instabilities and torque-induced yaw. Setting it to

maximum will give the most realistic response, (assuming the Difficulty Level enables the behaviour),

while minimum will dampen the response entirely. Adjusting the slider enables the user to become

accustomed to the behaviours by reducing the workload necessary to manage them. For the most

realistic behaviour and challenging experience it is recommended that this slider be set to maximum, (all

the way to the right.)

The following sub-sections describe each of the difficulty level selectable features and dynamics in

detail:

3.4.1.1 Torque Induced Yaw

Isaac Newton’s third law of motion states “For every action, there is an equal and opposite

reaction.” Therefore, as the helicopter’s engine turns the main rotor, an equal and opposing force

is generated attempting to turn the helicopter’s fuselage in the opposite direction. For a helicopter

with a counter-clockwise rotating rotor like the DodoSim 206 FSX, the body of the helicopter is

trying to turn clockwise, (i.e. From the pilot’s perspective the nose is trying to turn to the right.)

This is referred to as Torque Induced Yaw. The tail rotor’s primary function is to counter this

tendency using opposing thrust. As the power applied to the main rotor changes according to the

pilot’s power demand, (using collective pitch), so does the force required to counter the opposing

yawing tendency.

What this means for a pilot is that as collective pitch is applied, an increasing amount of left pedal

is required to maintain a constant heading. As collective pitch is decreased, the torque induced is

lessened and therefore less left pedal input is required.

Pilot Information: It is normal to have to apply significant left pedal in order to maintain a constant

heading in a hover. Whilst on the ground the friction of the skids on the surface may greatly reduce

torque-induced yaw, which will act suddenly once contact with the ground is broken. Differing

surface types provide varying amounts of ground friction.

Rotor direction

Torque-Induced Yaw direction

Tail rotor thrust direction