Definition
A type of aileron in which the leading edge of the upraised aileron projects below the wing's lower surface into the airflow, increasing drag on that side. This counteracts adverse yaw by producing extra drag on the descending wing — the wing the pilot is rolling toward — helping balance the drag created by the lowered aileron on the opposite wing.
Plain English
An aileron designed so that when it goes up, part of it sticks down into the airflow underneath the wing. That extra drag helps the airplane turn smoothly instead of yawing the nose the wrong way during a roll.
Context Anchor
Seen in discussions of flight controls, aileron design, and how airplanes reduce adverse yaw during turns.
Derivation
Named after Leslie George Frise, a British aeronautical engineer who developed the design in the 1930s. The name is simply the inventor's surname applied to the aileron type he created.
Why Pilots Care
Reduces adverse yaw during roll inputs, allowing more coordinated turns with less rudder correction and lower pilot workload.
Intuition Check
Do not read “frise” as “freeze.” The important point is that the raised aileron sticks slightly down into the airflow and adds drag on that wing.
Example Sentence 1
The trainer uses frise-type ailerons, which reduce adverse yaw by adding drag on the wing being raised.
Example Sentence 2
Pre-flight inspection confirmed the Frise-type ailerons moved freely and that the offset leading edges were undamaged.