Flaperon rivets missing

[GMKman]

Hello. I'm new to Kitfox ownership and have recently purchased a Kitfox vixen and have noticed that my left flaperon is missing 3 rivets on the trailing edge. Is this a normal maintenance occurrence? Should I just get the rivet gun out and put some new rivets in or should it be replaced?

[TahoeTim]

a little scary

looks like its delaminated - consult the experts on that one

[Dave S]

Brad,

First time I have ever heard of this happening....no...not a normal occurance - not at all.

A couple things on construction of the flaperons - 1) the flaperons are laminated at the factory - the spar tube, foam ribs and trailing edge of the flaperon are bonded together in a jig at the factory, I believe bonding is done with Hysol. 2) The builder is the one who puts the rivets in the trailing edge.

In any case - looks like in addition to losing some rivets - possibly the foam rib has delaminated as well as the trailing edge.

Check the rivet holes - The original spec calls for the builder drilling 3/32" holes for the 3/32" rivets using a #40 wire gauge drill. Check to see if the holes for the rivets are 3/32".....This is the only place on the plane where the smaller rivets are used. If the original builder happend to have used a #30 wire gauge drill (which is used all over the plane for other rivets) - that would result in the 3/32" rivets not fitting tightly enough to grip...I have no idea if that is what may have happened - but it would explain what you see if it did happen. Also check the trailing edge rivet spacing - the specification is 4" spacing. For the missing rivets - also check to see if deburring may have been overdone - the skin of the flaperons is thin and if a deburring tool was pushed too hard - it could have enlarged the rivet hole enough to let the rivet pull through.

In any case - I don't know if it is even possible to do a thorough/safe repair if the ribs delaminated from the skin as the original assembly is done in a factory jig (except for the ends and the riveting of the trailing edge).

Check the rivet holes for size in relation to the size of the rivets which should have been used - again - I don't know that from the photo but it's a place to start to figure out why this happened because I don't think this happens if everything is assembled according to the manual.

Wish you luck,

Dave S

[HighWing]

Not an expert. Since the flaperon has a spar running full length that bears a good portion of the control torque, this is what I would do. I would squeeze the trailing edges together using clamped half inch angle iron top and bottom. If the entire trailing edge lines up, I would first clean the mating surfaces then glue the trailing edge back together with a structural epoxy adhesive. After curing, add back in the rivets. Regular clear packing tape would make a good separating medium to prevent glue adhesion to the angle.iron. i should mention that the rivets are like "suspenders" to help support the adhesive - "belt". If the trailing edge won't line up you may need a new flaperon.

[cap01]

if you do determine that you can rehysol and reinstall rivets be sure not to use ad rivets, use only a rivets and don't use a rivet gun . the a rivets squeeze easily. the flaperon skin is way too thin to try and shoot rivets

[TahoeTim]

I am wondering if the damage was a result of a wing fold accident? Are there any dents in the trailing edge?

[GMKman]

No, there are no dents anywhere throughout the flaperon. Not even any scratches. I just got the plane a week ago and noticed it yesterday during preflight.

[t j]

I had a flaperon delaminate on the trailing edge early on during my flight testing due to a poor job of riveting I did. I had used a 100 degree counter sink to taper the holes in the top skin to get a flush fit of the solid rivet heads. That was a bad idea. A rivet head had pulled through the skin and the trailing edge popped apart right there.

I re-glued the delaminated spot with hysol then drilled out all the solid rivets and replaced them with aluminum pop rivets. No more problems.

[GMKman]

Thanks for.the advice. The holes are a bit sloppy so thinking about going to 1/8 pop rivets and using Hysol. Again, new to Kitfoxes and Googled Hysol and found many different types. Is this the one you guys recommend? What prep do I need to do?

[Dave S]

I believe Kitfox uses the 9460 - should be in their parts catalog page 28