Do I just need to Man-Up?

[Area 51%]

I'm to the point of fitting the leading edge skin on the LH wing. The upper and lower aft skins went on without a hitch. (That is,unless you count the errant flutes.)

Per the Sonex installation instructions, I fitted the leading edge to the upper spar cap and piloted the ribs to the skin. Flipped the whole mess over and clecoed the LE to the lower spar cap. So far........so good. The closer I got to the leading edge while piloting the skin to the ribs, the pressure required to close the gap between skin and rib has gotton to what would seem to be unreasonably high. There is a lot of distortion of the skin, and it seems impossible that the last row of clecos/rivets won't pull through the rib flange.

I removed the clecos from the top of the LE skin (except for the skin-to-spar), and the bottom of the skin lays quite nicely on the ribs. I drilled the forward-most lower hole at this point. With the lower clecos in place, I can get all the uppers in, except the forward-most row. The skin distorts, just as it did on the bottom.

When I removed the skin from the box, the relaxed angle was slightly more than 90%. Is there a step I missed, such as tightening the radius at the leading edge? If so, how is that accomplished and still have the tangency line come out at the correct location?

Or do I just need to Man-Up, push hard, and play the cards that Mother Sonex has dealt me?

Wishing my passion was for playing with dolls, instead of airplanes, here @ Area 51%

[peter anson]

There's probably several ways of doing this. I think most people with kits have to tighten up the bend a little using either the vacuum bagging method or the Tony Spicer bending brake. I bent the skins using the Tony Spicer method so they were about right. Here's a photo of the wing as I was fitting the leading edge skins.
The formers were cut from particle board. They were a fairly neat fit - the cut-out was just the rib outline plus skin thickness plus a small clearance. You can see that I also used a couple of ratchet straps to hold everything in place. From memory, I thought I used a saw horse to support the main spar but it's not visible in the photo so I must have simply clamped the rear spar to a block on the bench. The piece of wood poking out of the forward rib lightening hole is a notched stick that was used to keep the ribs aligned.

Peter
Sonex 894 scratch built

[Bryan Cotton]

I manned up. I pushed hard while Adam drilled or riveted. We did the top first and then the bottom. It was not perfect but it was fine.

[gammaxy]

Have you seen these instructions from Sonex?
https://www.sonexaircraft.com/documents ... W07-02.pdf

It describes how to use ratchet straps to pull the leading edge skin tight. You need to have a board in the channel of the rear spar to keep the straps from deforming the flanges. Also, make sure the boards on the leading edge won't scratch your leading edge skin.

Make sure to think it all the way through so that the ratcheting mechanisms are oriented and positioned so they won't damage any skins.