Trailing edge ribs glued in the wrong position....Thoughts?

[William Davis 4]

This forum has been great helping me through the final build of my newly acquired avid flyer model c. I purchased the plane already built and covered with the wings rigged but flaperons yet to be installed. The manual calls for the Flaperon control horn tube to be 3/16" above the welded fuselage tab. Well I got my right side to about 1/2" above the welded tab. This is 5/16" higher then the manual states but is still fine as when the turttle deck in installed the Flaperon control horns don't hit until the very extreme position. Now the left Flaperon is a totally different story and he is where the problem is. My left Flaperon control horn tube is 1 3/16" above the welded fuselage tab, this is 1" higher then it should be and when the turttle deck is installed the Flaperon control horn hits the turttle deck. I tracked down the problem to the first 3 root trailing edge ribs; they are NOT in trail with the other ribs. Since both of my wings have fuel tanks the tanks take the place of 3 main ribs, but have you glue 3 trailing edge ribs that run from the rear spar to the trailing edge wire. The position of these ribs at the furthest aft point is to be determined by clamping a long aluminum tube to the other remaining ribs, that are full length so the trailing edge of these ribs are set by the rib design, then one by one glue in the 3 trailing edge ribs clamping them to the aluminum tube to set the proper height of the end of the rib I relation to the rest of the ribs. If my wing wasn't already covered and painted beautifully i wouldn't be so apprehensive of what I'm pretty sure is the only fix; to strip the wing of covering, re position the 3 trailing edge ribs, then recover and re paint. Anybody have some advice you could give me, would be much obliged.

Thanks

Bill

[EDMO 1078]

Not having but a few minutes to think about this, I have two thoughts:

1. Modify your flaperon hangers.

2. Modify your ribs.

Got to think some about HOW?

Maybe someone else has a cure for your problem so you don't have to tear up your wing?

EDMO

[akflyer 1427]

1st thing.  With the flaperons in place, do they move smoothly or do they "cam" over center.  My ribs were a little out of align and my flaperons would cam over center and flop one direction or the other.  I expoxied dowels in the holes and redrilled the flaperon mounts.

 

you could makes a scarf joint on the rib tail and glue another piece of ply on it and glue / bolt aluminum on each side of it to extend the hangar.  If you do the last rib only your probly going to have to do the dowel trick and redrill the remainder of the hangars to keep the flaperon from "caming" over and getting a bow in it.

 

[akflyer 1427]

one other though, I am sure you did it though.. are your struts rigged correctly? 

 

[William Davis 4]

Thanks all for the responses. The Flaperon has not been drilled in place yet and is clamped in place. Making a scarf joint may work but not sure I feel comfortable making it strong enough. I may do more damage. Is it possible to heat the trailing edge ribs up with a heat gun and reposition then reglue in proper position. I could cut holes on the covering to get the heat gun in and then re patch the wing when finished? I would have to of course reposition the ribs and I wonder what this would do to the covering on the bottom of the wing. Think it would develop a large wrinkle? Think the top covering would stretch enough?

Thanks

Bill

[1avidflyer 1983]

I would wonder if you were to put a digital level on the rib next to the fuselage on each wing, are they the same?  (same angle of attack)   Leni mentions  if the lift struts are the same, and I agree, but check the wings at the fuse. first then further out.  I'm just guessing, but you have to start somewhere, eliminating things as you go....  Jim Chuk

[EDMO 1078]

One of the UK's mandatory modifications is to sandwich the trailing ribs between .025 aluminum angles glued and riveted - Some in the US have made this modification to their ribs to strengthen or fix them. You could use this method to change the rib ends and reinforce them like Leni said.

The other possibility is to add material to lengthen the steel flaperon hangers by making a longer hanger and riveting it to the old one with structural rivets to make the flaperon hang straight in a lower position, or simply cut the vertical arm and rivet in an extension strap after clamping them for a test fit.

If one wing is slightly out of being true, you may have to make some adjustments on your controls to keep from having a "heavy wing" after test flights.

EDMO

Edited 22 Feb 2015 by Ed In Missouri

[saskavid 47]

so what is the serial number of this air frame/ project as it came from avid? There are some implications with crooked airframes causing a bit of this maybe at times but sounds like you have a bigger problem with the flap attach ribsbeing glued in the wrong place maybe???

[High Country 69]

what about welding extensions onto the flaperon brackets to bring them down where they need to be but still keeping the original mounting the same. just another option to consider

[EDMO 1078]

what about welding extensions onto the flaperon brackets to bring them down where they need to be but still keeping the original mounting the same. just another option to consider

You could weld if you can keep the heat off of the plastic bushings - That's the reason I suggested rivets.

EDMO

[TJay 1041]

i would just do what was mentioned Mr.  Add some plywood under that rib and rivet and glue on aluminum pieces to bring them down a bit like the kitfox rib stiffeners. just make them a bit taller like was mentioned before in this post. here is mine, yours could be the same just a little bigger. what ever you do don't give up on her, it is a really nice looking plane.

 

[wolves200 31]

AC.43.13 blah blah blah, manual, the one founded on the FAA website for accepted methods repairs; has some pretty good suggestions as to how to repair this. it Shouldn´t be a problem, just like T-jay´s pictures here.

 

http://www.faa.gov/documentLibrary/media/Advisory_Circular/Chapter_01.pdf

 

Regards

Dimi3

[EDMO 1078]

This strengthening process came from the UK, not AC43-13.

See Kitfox Service Bulletins/Letters.

EDMO