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Wrapping Leading Edge Skins

Posted: Wed Apr 25, 2018 7:17 pm
by GaryK
I had quite a struggle getting my Leading Edge skins to wrap around and meet the predrilled holes. After clamping the Bottom side on, the holes were about 1/2" off from lining up on the top side when wrapping with no tension. I first tried 6 web clamps but without any standoffs ,they would also put down force on the stringers against the rib flanges since they were not close to dropping in the notches. Next added a 2x4 x 16' long, standing on edge, to hold the web straps at higher angle. This avoided down force on the ribs but when web force was put on skin, it was buckling the leading edge ribs, especially the thinner ones toward the tip.
My final configuration was wedging wooden temporary stiffeners inside the leading edge ribs under the web straps and at the outside rib. They held out the Front spar by transfer support from Main Spar. Did not need wedges toward the Root ribs since the Root Rib is so stiff. I was able to remove these through the access holes and reaching between rib cutouts. Another critical item is making tapered blocks from 2x6 material to protect the trailing edge top skin that overhangs the Rear Spar.
Temp Rib Stiffener.JPG
Temp Rib Stiffener under web clamps and at Tip Rib
Web Clamp Protctive Blocks.JPG
Tapered Blocks to match skin angles and avoid web strap damage to Trailing Edge skin

If anyone has any other techniques, I liked to hear about them. Would have been nice to have hints in manual. Not looking forward to having to do this again when clamping it back on after Prosealing and riveting the Bottom skins. At least now I have a technique, just need to make sure the wooden stiffeners are removed, wouldn't want them rattling around near the Aileron Control Linkage.

Re: Wrapping Leading Edge Skins

Posted: Thu Apr 26, 2018 7:21 am
by Mike Espinoza
I agree the manual needs to be rewritten with better detailed instructions.

This is how I did mine. I removed all clecos from the top of the LE (leading edge) skin. Then turn the wing upside down again and let the top of the LE skin hang loose. Drill only the LE rib holes at this time. Before drilling the front or main spars cleco both the top and bottom of the LE skin.

Don't worry about Prosealing. Once the main spar is drilled I push the LE skin down and back. Hold it close to the main spar and use an 1/8" ice pick through a rivet hole on the skin and align with the main spar. While holding the skin down, place a few clecos into the skin and main spar to hold it in position. Don't put a lot of pressure on the rivet holes when prying with the ice pick to avoid elongating rivet holes.

Hope this helps.