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Principles of Helicopter Flight Flashcards

7 cards from real SIFT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Principles of Helicopter Flight flashcards as text

  1. What is translational lift in helicopter flight?

    Answer: Lift generated by forward flight that improves rotor efficiency

    Translational lift occurs when forward airspeed moves the rotor out of its own downwash, allowing each blade to encounter undisturbed air and generate more lift.

  2. What is the primary purpose of the tail rotor on a single-rotor helicopter?

    Answer: To counteract the torque produced by the main rotor

    The tail rotor produces thrust opposite to main rotor torque, preventing the fuselage from spinning in the opposite direction.

  3. During autorotation, how does the pilot control rate of descent?

    Answer: By adjusting collective pitch

    The pilot uses collective pitch to manage rotor RPM and control the rate of descent during autorotation.

  4. What is gyroscopic precession as it applies to helicopter rotors?

    Answer: A force applied to a spinning rotor acts 90 degrees later in the direction of rotation

    Gyroscopic precession means a force applied to a spinning disc takes effect 90 degrees in the direction of rotation from the point of application.

  5. What is blade flapping in a helicopter rotor system?

    Answer: The up-and-down movement of blades to equalize lift between advancing and retreating sides

    Blade flapping allows rotor blades to rise on the advancing side and descend on the retreating side to compensate for dissymmetry of lift.

  6. What condition is known as 'retreating blade stall'?

    Answer: Stall of the retreating blade when its angle of attack exceeds critical limits at high forward speeds

    Retreating blade stall occurs at high forward speeds when the retreating blade's slowed relative airspeed requires excessive pitch to maintain lift, exceeding its critical angle of attack.

  7. What is the effect of increasing density altitude on helicopter performance?

    Answer: Reduced lift, decreased engine power, and degraded performance

    Higher density altitude means thinner air, reducing rotor lift efficiency and engine power output, significantly degrading helicopter performance.