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Trailing edge bend?

TASEsq

Well Known Member
Patron
Is it normal for the AEX Trailing edge wedge to have a slight bend/bow in it?

I was going to use it to match drill an alu tube to help keep the trailing edge straight, but with the bend in it I can’t! The holes punched in the skin are in a nice straight line and it seems to pull the wedge straight - hopefully this doesn’t translate into a bend in the assembly later?

The bow is measured at 1/16” at the most.

Here’s an image showing the bend/bow - the ends of the wedge are aligned with the straight tube.
https://photos.app.goo.gl/eLUnFJJnbLpgXRz46
https://photos.app.goo.gl/FkWu3Q7Y1SbXMHsr5

Holes nice and straight:
https://photos.app.goo.gl/9HbwGgDMt9MgAhg17

I suppose I can still match drill the tube from the wedge if I’m careful to align the tube with the edge of the straight tube, but I would have expected it would have come straight. Wondering how everyone else has fared.
 
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I used a piece of .125 x 1.5 x 1.5 alum angle on the edge of my workbench and match drilled the skins & TE wedge to the angle all at the same time. Edges are straight.
 
The "bow" occurs because of the compression of material inside the neutral axis of sheet (when looking on edge.) from bending the material.

It can (as suggested) be pulled into line, or you can use some very judicious shrinking of flanges or other "massaging" techniques to straighten it out.
 
Have you considered using the skin holes to match drill? My problems were caused by using the full assembly as a match drill pattern. I would think using one skin only would reduce the risk significantly and as you said the holes in the skin are perfectly straight.

Also, be aware that when you countersink the wedge you're going to get a knife edge condition on it. It's unavoidable and the holes will be slightly enlarged in the wedge. Take the scrap piece you cut off the end and try it. You'll see what I mean.

It's OK in this case. The strength of the TE joint comes from the dimples resting in the countersinks. When they're riveted into place the clamping insures the strength. It's important not to have any proud manufactured heads after riveting. If so, drill out and do over.
 
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Hi Art,

Thanks again for your reply.

I had considered the skins - however if i screw up a skin then the cost to send a new one to Australia would be astronomical. The AEX wedge wouldn't be so bad... Plus the thickness of the wedge seems to work really well with the brass tube tool i made to align the drill. It fits a 1/16" drill perfectly into the centre of the tube, and the tube fits snugly in the 3/32" hole already in the wedge. Once it's centre drilled (and at the correct angle too), i then updrill to 3/32" to match the hole in the AEX wedge. Seemed to work ok on the practice piece i did - the holes in the wedge were not enlarged. I will then cleco the tube to the rudder and match drill the whole lot to #40.

i realised that the alu tube i purchased will prevent me from squeezing the rivets, so i'm going to get an angle instead today and match drill that.

I am still working up the courage to have a go at the trailing edge in the next day or so - i think if i start in the centre and clamp / cleco the wedge keeping it aligned with the straight edge of the angle i should be ok?

Here's a photo of the "tool":
https://photos.app.goo.gl/Kxpk2ZNaSvntFUf96
https://photos.app.goo.gl/q4KvJAfBaiBhQhrv6
 
Trent,

I understand your concern. Sounds like you have a plan to proceed, but I'll make another suggestion as well.

1. Drill one hole in your tube and cleco the skin to the tube.
2. Clamp the other end of the skin in place without drilling.
3. Mark all of the holes on the tube with a Sharpie using the skin as a guide.
4. Remove the skin and adjust the wedge as required to match the marked hole locations.
5. Clamp the wedge firmly to the tube and drill.

This will be no risk to your skin and gives you a better chance to get the holes aligned properly. Also consider drilling the holes in the tube biased to one side so if you do get something other than a straight line of holes you have another shot to get it right.

i realised that the alu tube i purchased will prevent me from squeezing the rivets, so i'm going to get an angle instead today and match drill that.

I am still working up the courage to have a go at the trailing edge in the next day or so - i think if i start in the centre and clamp / cleco the wedge keeping it aligned with the straight edge of the angle i should be ok?

Here's a photo of the "tool":
https://photos.app.goo.gl/Kxpk2ZNaSvntFUf96
https://photos.app.goo.gl/q4KvJAfBaiBhQhrv6

When you do the final riveting of the TE you won't have your guide tube/angle attached. The double-sided tape or Proseal you use on the wedge will insure that the assembly will be more or less locked together even without rivets. As I understand it, that's the purpose of the adhesive. It's not structural. It's only a manufacturing aid to get a straight TE.

Once it's cured you rivet using the method outlined in Section 5. No support tube/angle is necessary.
 
Thanks Art,

Appreciate your message - that?s a good idea thank you!

My plan is to actually use an angle for the TE (1.5? x 1.5? x 1/8?) - I?m not sure why I purchased the tube - brain fart. This will allow me to keep the angle attached and squeeze the te through the angle. Least that?s the plan.
 
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