Greyhead

In my SE5a thread I have mentioned using the differential mix; in the model shop this morning I was talking to a modeller who is fairly new to the hobby who asked what differential mix is, so I though a simple explanation might be helpful.

What is Aileron Differential? It is simply when an aileron moves more in one direction than the other, in practice we use more up movement than down

Why do we use Aileron Differential? We use it because the aileron deflected down produces more drag than the aileron deflected up; the up aileron is going into “thinner” air (this is why the wing lifts) than the down aileron. At it’s worst it produces adverse yaw and the aircraft actually turns the wrong way!

How do we get Aileron Differential? There are 2 ways, mechanical and electronic.

For the mechanical method we use offset cranks, which can be the control horn, a bell crank or the servo arm itself, or even a combination of all three. The idea is to make the angle between the arm and the actuating rod more than 90º if the control horn is on the top of the aileron and less than 90º if the control horn is on the bottom of the aileron.

With “computer” radios we have an electronic mix; we use a separate servo for each aileron and the electronics make the servos move more in one direction than the other.

It's as simple as that.