UP AILERON MOVES MORE THAN DOWN AILERON

[I-Can-DO,3D]

On my radio i can set my ailerons so that when the aileron that is up is traveling say 1 1/2'' and the other aileron is down say 1''.What is this function called?And what is it used for?

[TonyThomasian]

aileron differential if i'm right..???...???...???

[Vic3D]

It's called differential and it's used to make the plane roll axially.

The lower part of the wing has more airflow than the top, making up-aileron less effective than down-aileron, so you increase the top aileron throw to make it roll axially. Typically you increase the top somewhere between 105-115% in aerobatic models.

[Edge540T_Flyer]

Some types of aircraft require "aileron differential".
Its got to do with having more lift on one wing and less drag on the other or visa versa. It keeps your aileron rolls more axial once you find the proper adjustment.
You want to have equal amounts of drag versus lift so the wings are rotating around the fuselage at the same rate of speed, otherwise your roll is more of a "barrel roll".

[Pro1Foam]

	Quote: Originally Posted by Vic3D
	It's called differential and it's used to make the plane roll axially. The lower part of the wing has more airflow than the top, making up-aileron less effective than down-aileron, so you increase the top aileron throw to make it roll axially. Typically you increase the top somewhere between 105-115% in aerobatic models.

What if you are inverted most of the time?

[TonyThomasian]

LOL

[Stainless Skills]

haha, same thing.

[I-Can-DO,3D]

[quote=Edge540T_Flyer;194436]Some types of aircraft require "aileron differential".
Its got to do with having more lift on one wing and less drag on the other or visa versa. It keeps your aileron rolls more axial once you find the proper adjustment.
You want to have equal amounts of drag versus lift so the wings are rotating around the fuselage at the same rate of speed, otherwise your roll is more of a "barrel roll".

[/quote

So when you find the right adjustment this will make your rolls and snaps and other axial moves tighter and more precise then?

[DKjens]

I would think that the two major factors in aileron differential are:
1. Hinging method, i.e. top hinge like Composite-ARF or other,
2. Wing placement on fuse, i.e. low wing like Caps, Sukhoi and some Extras, mid wing like Edge540, Giles, MX2, Yaks and some Extras, high wing like Aeronca and the like.

The hinging gives itself, an aileron on a Composite-ARF gets smaller as it moves down and remains the same as it moves up, usually more down than up is required.

Wing placement is a factor, because the fuse CL and the wing CL are not the same if it's not a mid wing airplane. On a low wing, like a Cap, you would want the wing and the fuse to roll around a common CL, which is neither of the individual part's CL, so the wing should be set to do a slight barrel roll, i.e. a little more down than up aileron. A mid wing should be neutral, a high wing should have a little more up than down.

Whether flow is different between top and bottom surface is irellevant, the whole thing reverses halt way through the roll, and as has been pointed out, what if the roll is initiated from inverted?

[Pro1Foam]

	Quote: Originally Posted by DKjens
	I would think that the two major factors in aileron differential are: 1. Hinging method, i.e. top hinge like Composite-ARF or other, 2. Wing placement on fuse, i.e. low wing like Caps, Sukhoi and some Extras, mid wing like Edge540, Giles, MX2, Yaks and some Extras, high wing like Aeronca and the like. The hinging gives itself, an aileron on a Composite-ARF gets smaller as it moves down and remains the same as it moves up, usually more down than up is required. Wing placement is a factor, because the fuse CL and the wing CL are not the same if it's not a mid wing airplane. On a low wing, like a Cap, you would want the wing and the fuse to roll around a common CL, which is neither of the individual part's CL, so the wing should be set to do a slight barrel roll, i.e. a little more down than up aileron. A mid wing should be neutral, a high wing should have a little more up than down. Whether flow is different between top and bottom surface is irrelevant, the whole thing reverses halt way through the roll, and as has been pointed out, what if the roll is initiated from inverted?

Congratulations! You have the correct answer!

[Tired Old Man]

To finish things off, differential is generally required because the aileron moving downwards creates more drag that the upwards moving aileron. This creates a condition called adverse yaw, slewing the plane in a direction opposite the roll. It's not about unequal lift.

As DK noted, a living hinged plane like Comp Arf requires differential just to keep things even.

[JimC-MD]

Upright and inverted would not be an issue if you checked for required differential on a vertical down line to see if the fuse is walking. Set is to roll true on the down line and fly out the rest of it is one method that you will see used.