flight controls

FLIGHT CONTROLS

Four basic flight controls

1. Cyclic pitch control2. The collective pitch control3. The throttle4. The antitorque pedals

• The collective and cyclic controls the pitch of the main rotor blades

COLLECTIVE PITCH CONTROL

• The collective pitch control, located on the left side of the pilot’s seat, changes the pitch angle of all main rotor blades

• Collective pitch control is raised there is a simultaneous and equal increase in pitch angle of all main rotor blades

• Done through a series of mechanical linkages

• As the Pitch angle increases,

Angle of attack increases,

Drag increases, and

Rotor r.p.m. decreases

• In order to maintain a constant rotor r.p.m a proportionate change in power is required to compensate for the change in drag.

• Accomplished with the throttle control

THROTTLE CONTROL

• The function of the throttle

To regulate engine r.p.m

• If the correlator or governor system are not installed, the throttle has to be moved manually to maintain r.p.m.

CORRELATOR

• is a mechanical connection between the collective lever and the engine throttle

• When the collective lever is raised, power is automatically increased and vice versa.

GOVERNOR• is a sensing device

• senses rotor and engine r.p.m.

• makes the necessary adjustments in order to keep rotor r.p.m. constant

• are common on all turbine helicopters and used on some piston powered helicopters

• Some helicopters do not have correlators or governors and require coordination of all collective and throttle movements

COLLECTIVE PITCH / THROTTLECOORDINATION

• When the collective pitch is raised, the load on the engine is increased in order to maintain desired r.p.m.

• The load is measured by a manifold pressure gauge in piston helicopters or by a torque gauge in turbine helicopters

• The collective pitch is the primary control for manifold pressure, and the throttle is the primary control for r.p.m.

• The collective pitch control also influences r.p.m., and the throttle also influences manifold pressure

CYCLIC PITCH CONTROL• tilts the main rotor disc by changing the pitch

angle of the rotor blades in their cycle of rotation.

• The rotor disc tilts in the direction that pressure is applied to the cyclic pitch control

• If the cyclic is moved forward, the rotor disc tilts forward

• the rotor disc acts like a gyro

ANTITORQUE PEDALS

• located on the cabin floor by the pilot’s feet

• control the pitch, and

• therefore the thrust, of the tail rotor blades.

• The pedals are connected to the pitch change mechanism on the tail rotor gearbox

• Allow the pitch angle on the tail rotor blades to be increased or decreased

• Antitorque pedals compensate for changes in torque