vmsguy

Hello all...

I was wondering how to orient wing mounted aileron servos on swept wings.

I'm building a plane with a swept wing. A wing where the trailing edge is swept back. The ribs are still parallel to the centerline of the plane. I want to put aileron servos in the wing. I really dispise torque rods.

Do I A) run the servo and control rod parellel to the wing ribs, but hence at an angle to the pivot of the aileron. or B) run the servo and control rod perpendicular to the pivot of the aileron, at an angle to the centerline of the plane.

See attached drawing. The top half denotes option A. The lower half denotes option "B."

I'm thinking I want to go with option "A". It gives better wind efficiency, but won't there be stress trying to push/pull the aileron at an angle?

I am also wondering what would be the best hardware (specifically the control horn) to use. I'm thinking the good ol' dubro control horn found on my trainer isn't the best idea...


TIA

Lyndon

BadSplice

My Feedback: (1)

I would use a combo of the 2 options. Mount the Servo so its parallel to the ribs, this way its easist to make a good strong mount. Then run the pushrod so its perpendicular to the Aileron like in option 2. That way you get the best parts of both options.

Charlie P.

Of those two it would be option "A" with the clevis tipped to give a for & aft push/pull. If possible, place the control horn in the mid-part of the aileron to minimize twist. Your drawing shows it too far inboard.

vmsguy

My drawings were quick-and-dirty sketches I came up with in "Paint." Just something to illustrate. Definitely not intended to be considered scale. But I do appreciate the the thought of moving the servo to a more central location.

Is there another option?? How do others accomplish this task?

da Rock

The pushrods should be perpendicular to any hinged surface. If they're not, the connection at the horn will bind. Will it be enough that the clevis disconnects? You can use a balljoint connection. You still lose force or leverage, depending on how you look at it. Will it be enough that the servo draws more current? Yeah, but maybe not a lot more.

So how much drag will come from having the pushrod at an angle to the airflow. Depends on whether or not your servo arm is exposed along the span or projects out of the wing. And keep in mind that when a round rod is turned at an angle to the airflow, it presents an elipse shaped profile.

Figuring to save drag with A just doesn't have the numbers to be worth the negatives.

daveopam

My Feedback: (9)

Just make it 90 degrees to the hinge line.


David