Definition
An aileron design in which the up-going aileron deflects a greater distance than the down-going aileron on the opposite wing. This unequal travel reduces adverse yaw by increasing drag on the wing being lowered (rising aileron) and producing less drag on the wing being raised (lowered aileron).
Plain English
A setup where the two ailerons don't move the same amount when you turn the control wheel. The one that goes up moves further than the one that goes down. This helps the airplane turn cleanly instead of swinging its nose the wrong way at the start of a turn.
Context Anchor
Seen when studying airplane control surfaces and how the airplane responds to a turn input from the control wheel or stick.
Derivation
‘Differential’ comes from Latin differentia, meaning ‘a difference.’ Here it simply means the two ailerons move by different amounts — a built-in difference in their travel.
Why Pilots Care
Reduces the amount of rudder coordination required and lowers the risk of uncoordinated flight during roll maneuvers.
Intuition Check
Do not read “differential” as just meaning the ailerons move in opposite directions. Here it means they move by different amounts: more up movement than down movement.
Example Sentence 1
Many training airplanes use differential ailerons to help reduce adverse yaw when rolling into a turn.
Example Sentence 2
During preflight, the pilot noted the greater upward travel on each aileron, confirming the differential rigging was correct.