Just 1 Aileron

[Jerry In Maine]

Maybe a dumb idea...

I'm building a "blue-foam" sailplane that'll have an e-motor to get it aloft. The plane will carry a tiny digital camera so I can hopefully get some pics of the Maine coastline.

The cam will be on one side of the fuse. To balance it I thought of having only one aileron with it's related servo and linkage on the opposite side.

I know this will work to some extent - at least enough to give me some roll control for the camera lens "look" angle. I don't expect the plane to win any performance contests - but I'd like it to fly decent.

Curious if I can expect any negative traits from this...I imagine that I'll need substantial deflection on the one 'ron as compared to a conventional setup?

Any ideas?

Thanks

[vintage1]

It will work, but horribly asymmetrically. And you may get serious adverse yaw when the aileron goes down..

I would be inclined to give it dihedral and use rudder instead.

[BMatthews]

Some pylon racers used one aileron but they were using it so that the drag from the aileron would help pull the model around. For a sailplane that needs to turn both ways with good effeiciency this isn't really a good idea.

But if the camera will be out on the wing all the time then by all means help the static balance by putting the aileron servo out in the other panel and use some sort of pushrod system to transfer the motion to the camera wing's side. Or just use two servos and use a small balance weight out at mid span to cancel out the camera's weight.

[Brandano]

Or just move the aileron servo on the opposite wing further outboard, if the wing can take it... leverage counts a lot!

[Tom Harper]

I use a single aileron on my photo planes. Does not seem any different than using two.

I suspect that would not be the case for aerobatics.

[macboffin]

It will work, but horribly asymmetrically. And you may get serious adverse yaw when the aileron goes down..

I would be inclined to give it dihedral and use rudder instead. I endorse that thought. One aileron only works fine when it moves up, to push that wing down,(helps to yaw the plane a bit too) but "adverse yaw" when it moves downwards. The drag of the cam under-wing will be surprisingly low ; the weight can be balanced by a minimum amount on the opposite tip.

[Tom Harper]

I agree that rudder is enough for smooth control.

However, for photography, I (and Jerry may wish to) use a leveler to keep the camera aligned with the horizon. The FMA copilot requires aileron. In the leveling application the deflection is very small. I have not observed any yawing when using a single aileron.

[han_solo]

Why not locate the servo wherever you want and and have it linked all the way over to the opposite wing? I bet a pull pull system could route control over w/ negligable weight and not too much difficulty.

[John O'Sullivan]

One aileron will cause a bit of adverse yaw on dropping the aileron and will work, but the dihedral/rudder is a better option and there is no need to make anything more complex than it needs to be.
On the other hand, Maynard Hill who flew the first official model airplane to cross the Atlantic, did it on one aileron. http://tam.plannet21.com/

John

[Tom Harper]

John,

I believe it depends on the application. For small corrections in the roll axis it works fine with no visible yaw. In that case it has lower total drag than two ailerons. A single aileron is easier to construct and rig. And, it is a bit lighter.

My new Sr. Telemaster wing has a single aileron. We'll see how that works.

Tom

[edi]

I know it would work. On my 55" Fokker D.VIII I lost a servo in mid-air. During the flight, I did remark that the ailerons got rather ineffective, but I experienced no other problems. (There was a working rudder here, though.)

Another thing was my 35" Fokker Dr.1 where an aileron servo came loose *and* the rudder horn, too. (Don't ask.) This one was a bit more scarey, but I really only remarked the loss of the rudder. I did have a lot of inverted yaw, but you have that anyway with triplanes and I am just used to feed in some rudder for turning.

I wouldn't recommend this for aerobatics, but for what you have in mind, it should work.

[Texas Buzzard]

It will work, but horribly asymmetrically. And you may get serious adverse yaw when the aileron goes down..

I would be inclined to give it dihedral and use rudder instead.

......................................

Yes , YES. Put in about 4 degrees of dihedral under each wing so a rudder can coltrol it - I have used that for years......it works.

If the wing has a 60" span, then raise each wingtip about 2 1/2 " when joining the wings. That gives about 4.7 degrees dihedral for a V-dihedral wing.

:) :rolleyes: :cool: :p :)

[warhead_71]

You can use just one aileron. I've done it with a K-mart chuckglider -- it flew just fine... not acrobatic, but fine for high altitude cruising. Also, I made a couple of twin-boom plane's for AP and I followed the directions from FoamFlyer (http://www.qnet.com/~skif/plane.html) who uses single ailerons (and no rudder) all the time. Here's his home page (http://www.qnet.com/~skif/rcmain.html) -- be sure to check his 16 page gallery of planes.

[Texas Buzzard]

As Vintage said - It will work but with some adverse yaw.

Why not use a few degrees of dihedral ( 4 to 7 degrees under each wing) and slap a rudder on it? That will work just fine....I have flown a number of "rudder/dihedral" gliders with no ailerons. The more dihedral the greater the turning effect from that rudder.

[HugePanic]

1 aileron might make trouble at landings.

at low lift the aileron-wing-half might stall when turning to the opposite side due to the increased lift.

but basically two ailerons should have less drag when operated.
with one aileron you will need (more) then double the aileron-deflection than with two ailerons. this can not be efficient.

at a pylon-racer (as is know it) they have one aileron to USE the asymetrical drag as a rudder-comando (YAW) for the turns..

please correct me! :)

[Tom Harper]

Huge,

A pylon racer only turns one way. So, you put the aileron on the inside wing. That way you only use the low drag deflection and you turn with elevator.

I am flying an AP model with 1 aileron and FMA co-pilot leveler. I have observed the following:

1. To get the same control feel you need twice the aileron area.

2. For the small deflections used by the FMA leveler there is no noticable difference between one aileron and two. I am flying both.

3. For large deflection there is no observable adverse yaw.

4. However, the model turns left easily (left wing aileron), but right with difficulty. Some of this is the problem of turning against engine torque. There is a lesser problem with the two aileron model. I think the adverse yaw does not appear as 'crabbing' but simply as a force that fights a right turn.

[biber]

A pylon racer only turns one way. So, you put the aileron on the inside wing. That way you only use the low drag deflection and you turn with elevator.In fact you have got to roll as much to the left as to the right,
because just before turning you roll in and after
yanking it around you will want to roll it back to level again.
(though you could aswell do the missing 3/4 to finish the full roll to the left,
which would mean one half more than necessary including the extra drag)
It has sure nothing to do with adverse yaw.
It is just a way to make things simpler and lighter.
No current F5D model has that one aileron feature.

biber

[Tom Harper]

I mostly agree. If the model is stable it will tend to right itself.

My concern is whether the single aileron is the reason my AP model resists turning right. I suspect it is a contributor. Next flight I'll see if it has the same problem with rudder turns.

Tom

[Brandano]

If your model is stable it will most likely have some dihedral. If it does, then adverse jaw will result in adverse roll, and will be more noticeable when the aileron is deflected downwards.

[Tom Harper]

Brandano,

It has 3 deg of dihedral. That's probably what is happening. The adverse yaw is not visible but it is impacting control. The cure would be to use aileron only for leveling and rudder for turns.

[Brandano]

Or mix in some rudder to fight the adverse jaw, at the expense of slightly increased drag