Aircraft Propellers Notes

AIRCRAFT PROPELLERS (A)

1 - Purpose of a Propeller

• The primary purpose of a propeller is to convert engine horsepower into thrust.

2 - Thrust Production

• Thrust is produced by a rotating propeller in the same way lift is produced by a wing.
• Aerodynamic forces create an area of decreased pressure immediately in front of the propeller.
• The propeller moves into this area of low pressure, generating thrust.

3 - Aircraft Engine Propulsion

• The basic difference in thrust production between a turbojet/turbofan and a turboprop engine lies in the mass of air moved and the acceleration imparted to it.
• An engine-driven propeller imparts a relatively small amount of acceleration to a large mass of air.