Aircraft Propeller Systems Flashcards

During a propeller track check, one blade is found to be 3/4 inch lower than the others. The most likely cause is:

Answer: A bent blade

Track error exceeding acceptable limits (typically 1/16 inch for metal props) usually indicates a bent blade, which must be rejected or repaired by a certificated shop.

Which propeller type uses aerodynamic twisting moment as the primary force to increase blade pitch?

Answer: Hydromatic (Hamilton Standard) propeller

The Hydromatic propeller design relies on aerodynamic twisting moment combined with counterweights to move blades toward high pitch, with oil pressure moving blades toward low pitch.

A propeller with a designation of 74DM6A5 has a diameter of:

Answer: 74 inches

In the propeller designation system, the first two digits represent the nominal diameter in inches; 74 = 74 inches.

Before removing a propeller from an engine flange, the technician should FIRST:

Answer: Make a index mark on the flange and hub

Marking the hub-to-flange relationship before removal ensures the propeller can be reinstalled in the same position to maintain balance.

The beta range of a turboprop propeller system refers to operation:

Answer: Between flight idle and maximum reverse pitch

The beta range encompasses blade angles from flight idle through flat pitch to full reverse, used for ground maneuvering and deceleration after landing.

An aluminum alloy propeller blade has a nick on the leading edge. The correct repair method is to:

Answer: File the area smooth using longitudinal strokes and blend with surrounding contour

Small nicks on aluminum propeller leading edges are repaired by filing smooth with lengthwise strokes and blending the contour to prevent stress concentration.

Propeller slip is defined as the difference between:

Answer: Geometric pitch and effective pitch

Slip is the difference between geometric pitch (theoretical advance) and effective pitch (actual advance per revolution), representing aerodynamic inefficiency.