Flap Postion

[Sonex 772]

Hey All

I now have 10 flights on my Sonex, I ended up having to drop the left aileron down to keep the plane from wanting to turn to the left all the time.. I have the flaps come up where they both touch the rear spar and just wondering if there is another way to check to see if the flaps are in the correct position before I put the flap fairings on.. I would assume I have them both right, but want to make sure.. I didn't see any thing in the plans on adjusting the flaps..

Thanks
Mike

[phenry]

Mike,
There is a technic for setting up the flaps and the ailerons I think it is described on the wing drawings somewhere however Bob Meyers has some pictures of it here: http://meyersfamily.org/sonexlog113/index9.html
The other thing to consider is flying the plane before attaching the flap fairings in case they need adjusting. I have heard a number of builders talk about fixing turn bias by slightly adjusting flap position.

[rbarber]

You may want to note the flap position on the ground, maybe even mark it's relationship with the trailing edge of the top wing skin, then have a look while in flight. I found that the flex in the flap was the problem, as one flap would slide just a little bit further under the upper wing skin when loaded. I put a stop on the aft spar and it fixed the problem. Worth a look anyway.

Rob.
N157SX

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[N1906R]

Robert

I have the same issue with the right flap. At higher speeds it rolls slightly right. I put a temporary rubber stop on the rear spar at the hole for the pushrod. This pretty much stopped the roll. I have been trying to decide on a permanent solution, could you post some pictures of the stop you installed, I sure would appreciate any advice on the subject

Thanks
Jim

[rbarber]

I can, but don't have a photo handy, so it will be a couple of days perhaps. I simply bent a 0.060" thick piece of Aluminum in the shape of a "top hat" or _|--|_ (sorry, the dashes don't go high enough). I made it a little short, so I could add shim to get it just right. I riveted it behind the second rib in the flap (the most solid spot) to the aft spar. I had to add 0.025" to get it perfect. I will try to get a pic as soon as practical.

[N1906R]

Thanks Robert

Working finishing the filling and painting on wheel pants and cowl so am not flying for the next week or so. Sure appreciate the help

[rbarber]

Here's the pictures. [attachment=-1]uploadfromtaptalk1401317203409.jpg[/attachment]

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[rbarber]

And another for reference.

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[rbarber]

Sorry about the second picture. My phone cropped it too much. The location is at the second internal flap rib (going outward). If it is not clear, let me know and I will take another picture...

Rob.

[SNX1454]

Plans Sheet SNX-W02, Section A-A specifies how the flaps are to be rigged with 2 29/32” as the specified dimension. I am sure most of us did this and went on. What I missed was that this has to be the in flight dimension with all the tolerances taken out with the flaps loaded in the upward direction. Since there has to be slop in the system for it to operate, I am sure most of us are far off the mark because we set the flaps in the quiescent state. The flaps move upwards considerably from there.

A more appropriate setting could be achieved by pulling up on the flap to remove the slop and setting them there. When this is done, the flap doesn’t hit the rear spar and chip the paint. Also from here the trick of giving the heavy wing rod end a half a turn will have the expected effect, which it will not happen if the flap is hitting the rear spar. If the flap is hitting the rear spar when loaded upward all you are doing is removing slop from the system and nothing happens.

These things I know because I have done them all. DUH! The airplane flew pretty well in spite of all this.