Definition
A left-turning tendency caused by the rotating column of air that the propeller pushes back along the fuselage. As this spiraling slipstream wraps around the airplane, it strikes the left side of the vertical stabilizer and rudder, pushing the tail right and yawing the nose left. The effect is most pronounced at high power and low airspeed, such as during takeoff and climb.
Plain English
The propeller throws air backward in a spiral, like water from a garden hose with a spinning nozzle. That spiraling air hits the tail off-center, twisting the nose to the left.
Context Anchor
Encountered when learning why a propeller airplane may need right rudder during takeoff, climb, and other high-power, low-speed situations.
Derivation
Corkscrew describes the spiral path the air takes after leaving the propeller — the same shape as a wine-bottle corkscrew. Slipstream is simply the stream of air that slips past the aircraft after being accelerated by the prop.
Why Pilots Care
This effect is one of the four primary left-turning tendencies and must be countered with rudder to maintain directional control on takeoff and climb.
Analogy
Think of a fan blowing air through a loose spiral tube instead of straight across a room. Anything placed behind the fan would be hit from an angle, not just from directly ahead.
Grounding Statement
Picture the propeller throwing a twisting tube of air backward around the fuselage until it reaches the tail.
Intuition Check
Do not read “corkscrewing” as meaning the airplane itself is spinning like a corkscrew. Here, it is the propeller’s airflow that is spiraling around the airplane.
Example Sentence 1
On takeoff roll, the pilot fed in right rudder to counter the corkscrewing effect of the slipstream and keep the airplane on the centerline.
Example Sentence 2
In a maximum-performance climb the student pilot forgot the corkscrewing effect of the slipstream and allowed a slow left yaw to develop.