Army Aviation Information Flashcards

A thrust is produced by

Answer: The engine(s) of a helicopter

Thrust is the force that propels an aircraft. In a helicopter, the engine(s) are responsible for generating the power that drives the main rotor system. It is the rotation of these main rotor blades, powered by the engine(s), that creates the aerodynamic forces, including both lift and thrust, necessary for flight.

Which of the following does not refer to a typical helicopter control?

Answer: Dual

The primary flight controls of a helicopter are the collective, which changes the pitch of all main rotor blades simultaneously to control altitude; the cyclic, which changes the pitch of individual blades cyclically to control direction; and the anti-torque pedals (or tail rotor control), which control yaw. 'Dual' is not a standard flight control component.

Which of the subsequent is not a typical helicopter taxi maneuver?

Answer: Rotor Taxi

Standard helicopter taxi maneuvers include Ground Taxi (moving on wheels), Hover Taxi (moving slowly above the ground, typically below 20 knots and 20 feet AGL), and Air Taxi (moving faster and/or higher than a hover taxi, but still below normal cruising flight). 'Rotor Taxi' is not a recognized or typical term for a helicopter taxi maneuver.

During takeoff, blade flapping is utilized to:

Answer: Counter dissymmetry of lift

During forward flight, the advancing rotor blade (moving in the direction of flight) experiences higher airspeed and thus more lift than the retreating blade. This phenomenon is called dissymmetry of lift. Blade flapping, where the blades move up and down, is a crucial mechanism that allows the rotor system to equalize lift across the rotor disc, thereby countering dissymmetry of lift and maintaining stable flight.

Another name for settling with power is

Answer: Vortex ring state

Settling with power is a dangerous aerodynamic condition where a helicopter descends into its own downwash, causing the rotor blades to operate in turbulent air that has already passed through the rotor. This leads to a significant loss of lift and control, even with power applied. This condition is also commonly known as a vortex ring state.

An mechanical angle called an angle of incidence exists between

Answer: The chord line of the blade and the circular plane in which it rotates

The angle of incidence, also referred to as the blade pitch angle, is a critical mechanical angle in helicopter aerodynamics. It is defined as the angle between the chord line of a rotor blade (an imaginary line from the leading to the trailing edge) and the circular plane in which the rotor blade rotates. This angle is adjusted by the pilot to control the amount of lift generated.