1. Basic Propeller Principles
Kevin Jung

2. What is propeller? Consists of two or more blades Rotating wing
Transforms the rotary power of the engine into forward thrust

3. The Left Turning Tendency
The propeller causes the airplane to turn left.
Four major causes are
Torque
Corkscrew effect (Slipstream effect)
Asymmetric loading of the propeller (P-Factor)
Gyroscopic effect

4. Torque Reaction Newton’s Third Law of Physics
For every action, there is an equal and opposite reaction
When the airplane is in the air, this force is acting around the longitudinal axis, tending to make the aircraft roll to the left
When the airplane is on the ground during takeoff, torque will cause the airplane to yaw to the left.

5. Corkscrew Effect
At high propeller speeds and low forward speed, this spiraling rotation is very compact and exerts a strong sideward force on the aircraft’s vertical tail surface
It yaws the airplane to the left

6. Asymmetric Loading (P-Factor)
It is caused when one side of the propeller produces more thrust than the other side
At a high AOA, the downward moving blade has a higher resultant velocity, creating more lift than the upward moving blade
It yaws the airplane to the left

7. Gyroscopic Effect Less noticeable than other three
Produces a left yawing motion when pitching down and a right yawing motion when pitching up

8. Summary Propeller = Rotating Wing Torque – rolls and yaws to the left
Corkscrew effect – yaws to the left
P-Factor – yaws to the left
Gyroscopic Effect
Yaws to the left when pitching down
Yaws to the right when pitching up