Originally Posted by RCPC
what is the purpose of the wipers on the hinge gap? if the airflow is turbulent that far aft on the wing, will the wipers achieve anything? is the airflow turbulent that far aft? just curious, not trying to challenge you. i was just thinking about this a few nights ago while laying in bed waiting to fall asleep.
I have just come across this question- so here is my 2c for consideration. The aileron hinge point in some cases on the bottom will actually be very close to the transition point at close to 80% of the chord, but even the plastic strip would be enough to trip the flow in most cases, so this is rarely the reason for using the wipers.
The reason for using the seals is to reduce the surface friction drag of the hinge line as this is even higher in turbulent flow than in laminar - around 6 times higher according to Mark Drela. In severe cases it could even increase the wake dag as well.