Pitch Setting

Pitch setting refers to the angle at which a propeller blade is set relative to its plane of rotation. On fixed-pitch propellers, the pitch is set at manufacture and cannot be changed. On variable-pitch (constant-speed) propellers, the pilot adjusts pitch to maintain a desired RPM across a range of power settings and airspeeds.

Fixed vs. Variable Pitch

• Fixed pitch: One blade angle for all conditions; optimized for either climb or cruise; simple and lightweight; most common in single-engine trainers
• Variable pitch: Pilot adjusts pitch via propeller control; greater efficiency across a range of conditions; required for constant-speed operation
• Constant-speed propeller: Governor automatically adjusts pitch to maintain selected RPM as power and airspeed change

Feathering and Reverse Pitch

Some variable-pitch propellers can feather (blades to ~90° — edge-on — for minimum drag after engine failure) and some can reverse pitch (blades past fine pitch, generating thrust aft — used for ground braking on turboprops). Both require specifically designed propeller and governor systems.

Related Terms

See also: Feathered Propeller, Propeller, Manifold Pressure.