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Internal aileron linkage

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BoKu

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OK, can I ask another context question that I cannot see in your vid. The motion of the lead filled rod is circumferential at the farthest pinned joint at the rib. This seems to be generally moving vertically up and down along the shear web. How is that balancing out the flap? I can't visualize how you are transferring the moment of one to the other to balance across the rotation axis.
The flaperon section is connected to an arm on the carbon fiber bellcrank by a short push-pull tube. I couldn't show that in this video because the mold surface is in the way.
 

tallank

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I am interested in what internal aileron linkage methods you know of. I am only aware of how it is done in the Cirrus SR22, but I don't like the way they are using cables.

Is there any good solution to do it push/pull tubes? The easiest solution would be to "shorten" the lever arm in the aileron horn until it is within the aileron.

What method are the glider guys using? Please feel free to add some pictures.

BR, Andreas
My 1930 Fleet Model 2 project has internal pushpull linkage.

Allan
 

Jay Kempf

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OK, I just got it. This translates the linear movement of the pushrod into rotation and the weight rotates around an offset axis that has an identical moment to the flap. The up and down was confusing me without seeing the flap. Is the flaperon horn or horns conventional, as in non skewed actuation?

I will use this in the future for a bunch of things. Sort of like a lot of the little universal joints in a lot of landing gear legs to rotate the leg while retracting. You can never have a large enough library of solutions available.
 

geraldmorrissey

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Torque tubes. Mount the aileron to the tube, arrange bearings on the rear spar, devise a control system to twist the tube. Used quite successfully on the Stephens Acro and probably others.
 

BoKu

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OK, I just got it. This translates the linear movement of the pushrod into rotation and the weight rotates around an offset axis that has an identical moment to the flap. The up and down was confusing me without seeing the flap. Is the flaperon horn or horns conventional, as in non skewed actuation?

I will use this in the future for a bunch of things. Sort of like a lot of the little universal joints in a lot of landing gear legs to rotate the leg while retracting. You can never have a large enough library of solutions available.
Correct, the flaperon drive from the bellcrank to the horn on the upper surface of the flaperon is entirely conventional. Using a skew drive for the flaperon would have required center-hinging the flaperon, which would have been more trouble than I wanted. I used the skew drive for the mass balance because it was the simplest way to implement something that lives inside the wing and works well for decades on end.
 

BoKu

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Torque tubes. Mount the aileron to the tube, arrange bearings on the rear spar, devise a control system to twist the tube. Used quite successfully on the Stephens Acro and probably others.
Torque tubes are great for short distances where you have volume for a tube with lots of enclosed area. For longer distances they are fairly poor in terms of stiffness per unit mass.
 

BJC

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The torque tube ailerons in the Stephens Akro were replaced with push-pull tubes in the Extras (and other one offs). Lighter, and tighter, but look dorky in the cockpit.


BJC
 

pwood66889

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The Ercoupe uses push-pull tubes to actuate the ailerons. They go from the "mixer" where the rudder cables take off, through the stub wing at a funky bell crank, then to the aileron. Need a picture?
 

Scheny

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Cirrus.PNG
This is how it is done in the Cirrus. Quite similar like the Libelle, but actuated by pulleys, which rotate the red shaft around the center axis of the pulley disc. Due to that, it needs an additional axis (blue).

Does anyone have more pictures of ailerons similar to the Libelle?
 

Scheny

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@BoKu there are good linear slide bearings available from IGUS that I am planning on using. This one is for 5/8 (16mm) and can be clipped onto 3mm strong carbon panels:


I used the IGUS products for the steering of my boat, where I have a sidestick acting on a torque tube which is supported by two of these bearings. Slides almost without any noticeable resistance and needs no service at all. I heard that a lot of aircraft already use these products.
 

Jay Kempf

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View attachment 103563
This is how it is done in the Cirrus. Quite similar like the Libelle, but actuated by pulleys, which rotate the red shaft around the center axis of the pulley disc. Due to that, it needs an additional axis (blue).

Does anyone have more pictures of ailerons similar to the Libelle?
That's a big parts count to save one horn and a tiny fairing. What advantage does that give? The flap hinges are hang out in the breeze already anyway.
 

pictsidhe

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If using Igus, be careful to pick the right material. They have a pretty good online selector and are extremely helpful if you email them. The wrong material can be very disappointing
 

TFF

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I think the Cirrus is done that way to keep a the controls in the wing cove instead of having holes in the tank that have to be dealt with which would be way more complicated. It’s done like a big plane which is a nice touch.
 
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Jay Kempf

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If that's why that's a good compromise. Breaking into a composite structure for access to controls is always a tough design problem. If stuff can be bolted on outside it is always better.
 
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