Lesson 2 Aerodynamics of Flight Part 1 Flashcards
Induced Flow
The component of air flowing vertically
through the rotor system resulting from the production of lift.
Lift is always ____________ to the chord line
Resultant lift
How much of lift can be attributed to Bernoulli’s principle?
70%
How much of lift can be attributed to Newton’s third law?
30%
Parasite drag
The part of total drag created by the form or
shape of helicopter parts. (4x airspeed)
Profile drag
Drag incurred from frictional or parasitic resistance of the blades passing through the air. It does not change significantly with the angle of attack of the airfoil section, but it increases moderately as airspeed increases.
Induced drag
That part of the total drag that is created by
the production of lift.
The four forces of flight?
Lift, weight, thrust, drag
Relative wind
Air flow in relation to the direction of the surrounding air.
Translating Tendency
The tendency of the single-rotor helicopter to move laterally during hovering flight. Also called tail rotor drift.
______________ is pushed to the left of the tail rotor and __________ is going to the right.
Downwash, thrust
If left uncorrected, which way will a helicopter drift because of translating tendency?
It will drift to the right. Tail thrust to the right, turns the nose to the right, causing the helicopter to drift to the right.
Pendular action
The lateral or longitudinal oscillation of
the fuselage due to its suspension from the rotor system.
What three things cause pendular action?
Too late, too long, too strong (control movements)
Coning
An upward sweep of rotor blades as a result
of lift and centrifugal force.
