Principles of Helicopter Flight
Hovering flight
-Lift and thrust resultant
-Weight and drag
-Axis of rotation
-Coning
-Translating tendency
-Direction of airflow
-Ground effect
-Gyroscopic precession
-Pendular action
-Loss of tailrotor effectiveness
Forward, sideward, and rearward hovering
-Lift and thrust resultant
-Weight and drag
Forward flight
- Lift and thrust resultant
- Weight and drag
- Blade flapping
- Coriolis effect
- Translational lift
Increased lift as a result of directional flight, usually forward. We begin outrunning our vortices starting at the front of our rotor disc. Effective Translational Lift (ETL) is the helicopter fully outrunning its vortices, now operating in clean air. (16-24knots) - Dissymmetry of lift
causes uneven lift due to adv. and ret. sides, this is mitigated by flapping to reduce adv. side AoA and increase ret. side AoA - Transverse flow effect
Transverse flow is the increased lift on the front half of the main rotor disk as a helicopter accelerates into forward flight (9-15knots). The airflow running across the rotor disk on the front is more horizontal, thus increasing the AoA, as compared to the aft portion of the rotor disk where the airflow is still more vertical and AoA is less. - Retreating blade stall
- Low rpm blade stall
- Low G / Mast bumping
- Settling with power
This lesson was last edited 4 days, 18 hours ago.
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