2. INTRODUCTION TO FLIGHT CONTROL
Three major controls during helicopter flight
Collective pitch control
Cyclic pitch control
Antitorque pedals or tail rotor control
Additionally the pilot must control the throttle* and
monitor aircraft instruments.
*Not all helicopters require constant throttle adjustment due to an engine “governor”
Helicopter Flying Handbook 2012
3. COLLECTIVE PITCH CONTROL
Located on the left side of the pilot
Changes pitch angle of the main rotor blades
As collective pitch control is raised there is a simultaneous and equal increase in pitch
angle of all main rotor blades; if it is lowered there is a simultaneous and equal
decrease in pitch angle
The amount of movement in the collective lever determines the amount of blade pitch
change
Pitch angle changes the angle of incidence on each blade that a change also in drag
which affect the speed or revolutions per minute (rpm)
As pitch angle increases, angle of incidence increases, drag increase and rotor rpm
decreases.
Decreasing pitch angle decreases angle of incidence and drag, which will increase rotor
rpm.
“In order to maintain a constant rotor rpm, which is essential in helicopter operations, a
proportionate change in power is required to compensate for the change in drag.
This is accomplished with the throttle control or governor, which automatically
adjusts engine power.”
Helicopter Flying Handbook 2012
4. THROTTLE CONTROL
Its function is to regulate engine rpm through fuel
management
Manually twisting the grip of the throttle will allow for
maintaining rpm. In some cases a correlator or governor
system helps maintain desired rpm when the collective is
raised or lowered
Twisting the throttle to the left (counter clockwise)- increases
rpm
Twisting the throttle to the right (clockwise)- decreases rpm
Helicopter Flying Handbook 2012
5.
6. GOVERNOR/CORRELATOR
These devices help rotor and engine rpm and make adjustments to
keep a constant rotor rpm.
Once the rotor rpm is set, the governor (more fine tuning) keeps the
rpm constant resulting in no need to make adjustments to the
throttle (normal operations); the correlator is a mechanical
connection that gives course rpm adjustments with collective
movement.
Helicopter Flying Handbook 2012
7. CYCLIC PITCH CONTROL
Located in front of the pilot either between the pilot’s legs
projecting upward from the cockpit floor or a “T bar” that
swings downward
Allows for control of flight of the helicopter; moving forward,
rearward, left and right
“Total lift force is always perpendicular to the tip-path plane of
the main rotor”
Its purpose is to tilt the tip-path plane in the direction
horizontally desired
The cyclic controls the rotor disk tilt
Helicopter Flying Handbook 2012
8.
9. ROTOR DISK TILT
Rotor disk tilts in the same direction the cyclic pitch control is
moved
Cyclic moved forward- rotor disk tilts forward
Cyclic moved aft- rotor disk tilts aft
“Because the rotor disk acts like a gyro, the mechanical
linkages for the cyclic control rods are rigged in such a way
that they decrease the pitch angle of the rotor blade
approximately 90 degrees before it reaches the direction of
cyclic displacement, and increase the pitch angle of the
rotor blade approximately 90 degrees after it passes the
direction of displacement.” This is called gyroscopic
precession.
Helicopter Flying Handbook 2012
10. ANTITORQUE PEDALS
Located in front of the pilot at the cockpit floor
The pedals control the pitch and thrust of the tail rotor
blades
The helicopters fuselage and its rotation in the opposite
direction of the main rotor blades require a
counteraction and control.
To compensate for the torque of the main rotor blade, a
tail rotor or antitorque rotor is part of the design.
The pedals allow the pilot to control the pitch angle of
the tail rotor blades
Helicopter Flying Handbook 2012