Helicopters Flashcards
When banking the helicopter, vertical lift is directed into
horizontal movement,
bank of 25 degrees requires 10% increase in lift
thrust is primarily created by
converting lift alterations of the pitch angle and AOA
profile drag
drag created by the frictional resistance of spinning airfoils,
allows drag to increase as velocity increases
remains midway, not dominating nor negligible
parasitic drag
caused by the non lifting portions of the helicopter, weight of the helicopter and its equipment, most dominant type of drag and increases with airspeed
induced drag
byproduct of lift created by rotor, only drag that decreases as airspeed increases, primary force at low speeds but meaningless at high speeds
a helicopter can adjust to more weight on one side by
adjusting the angle of the rotor disk to stabilize
but will cost lift, reducing performance
front loaded center of gravity
identified by fuselage tipping forward
cases helo to pull forward when hovering making slowing down and forward movements difficult.
result of having a heavy pilot in front, little cargo at rear
solution: add weight to back of helo
Aft loaded Center of Gravity
identified by fuselage tipping backwards
cause the helo to pull backwards when in neutral hover, and make accelerating more difficult
Primary flight controls in a helicopter
Collective, throttle, cyclic, antitorque pedals
collective pitch control
used to create lift and control vertical movement
succeeds by altering the pitch of the rotor blades. increased pitch = lift
throttle
control power to the engine
used whenever the RPM drops or rises beyond value. clockwise turn increases Rpm
correlator
links the collective to the throttle, automatically increasing or decreasing the throttle as the collective is used
governor
electronic sensor that tracks the current RPM directly. it will automatically adjust the throttle as needed if the RPM is out of desired range.
with this, touching the throttle is rarely needed
Cyclic pitch control
used to generate thrust and control horizontal movement,
functions by altering pitch of the rotor blades
Anti-torque pedals
controls pitch of the tail rotor blades
purpose is to counteract the torque of the main rotor, and increase or decrease past it
a pilot can control rotation for a new heading