User manual

DodoSim 206 FSX User Manual

Page 64

4.1.3 Hovering and Slow-Speed Flight

Helicopters are by their very nature unstable and hovering requires constant attention and control

inputs. You should not expect to be able to remove your hands and feet from the controls and for the

helicopter to remain stationary.

It is suggested that you learn to hover the helicopter in steps, utilising the various difficulty levels.

(Refer to the table in the Difficulty Settings section for more information.)

The lowest level (1) will make the helicopter feel and respond in a very similar manner to the default

helicopters in FSX.

The next level (2) introduces Torque-Induced Yaw, Dissymmetry of Lift and Collective/Pitch Coupling.

You will be required to balance the torque-induced yaw with the anti-torque pedals.

The medium difficulty level (3) introduces the bulk of the helicopter behaviours applicable at hovering

speeds. Control sensitivities will be increased and so you will be required to make smaller, more

precise inputs and to anticipate the changes in aircraft behaviour they will cause.

The next difficulty level (4) introduces all of the flight dynamics behaviours you will need to master,

including having to account for wind direction and strength on the tail rotor efficiency and the effect of

wind on the horizontal stabiliser.

Complicating the pilot’s job somewhat; application of one control input requires simultaneous

adjustment of all the others in order to remain in complete control and prevent unwanted aircraft

reactions.

Hint: To experience all of the advanced behaviours yet have an easier job managing them, you can

reduce the “General Realism” slider in the “Aircraft->Realism Settings” dialog to lessen their effects.

4.1.3.1 Using the Cyclic “Stick”

The main rotor disc exerts huge gyroscopic forces and as such requires significant input to deflect its

“tip plane path” and effect a movement in the under-hanging helicopter’s fuselage. Due to this inertia,

rotor disc response lags cyclic control inputs somewhat and the pilot must anticipate the response to

each input and often correct for it before the response has occurred.

Effective cyclic control in a hover consists of constant, small control inputs. Large movements of the

cyclic will quickly result in large, unwanted attitude changes within the rotor disc that will move the

helicopter in the respective direction. The inexperienced pilot can quickly end up over-controlling the

helicopter and into what is termed “pilot induced oscillation.”

4.1.3.2 Using the Collective “Lever”

In the hover and slow flight, the collective is used to control the height of the helicopter above ground.

To adjust the height, only small adjustments should be made to the collective lever. As collective is

applied, more torque-induced yaw is generated and the pilot will have to compensate with appropriate

anti-torque pedal control.

Aggressive lifting of the collective lever may result in “rotor droop”, whereby the sudden demand in pitch

creates drag on the rotor before the rotor governor can compensate with increased fuel and engine

power. In this state, rotor RPM may decay and the helicopter will sink, perhaps dangerously quickly.

Pilot Information: A noticeable spike in the torque gauge’s reading accompanies rotor droop and

damage to the main transmission may occur.

To land from a hover, the pilot should lower the collective smoothly and only enough that the altitude

slowly begins to decrease. If performed correctly, no increase of the collective should be required to