In my quest to fabricate the modification to leading edges, all my research into the method that I should use to safely complete the modification has led me down a path that will require me to be able to bend several pieces of .032inch thick alclad aluminum into a sort of combined leading edge and joint plate part. Since the part that I have to make must be slightly smaller than the shape of the leading edge skin, I don't think I can use a section of the already-formed leading edge skin.
Another reason I can't simply just cut out a section of of the existing leading edge skin is that the parts will not fit back together snugly due to the amount of material that is lost from the actual cut, plus any deburring and edge smoothing that may be needed. The only way to get a part that will fit correctly is to cut one to the exact size from a different piece of metal. Without going into more gory details that can't be clearly understood unless you "see" what I am talking about, I'll just finish this section by saying that there area number of different reasons why simply cutting a section out of an existing skin just won't work for what I am trying to do.
I have to create a sub-skin structure that will adequately support and provide sufficient attach points for the outer skin assemblies for an area in between two of the leading edge ribs that are about 9.5 inches apart. I guess the best way to think of it would be a greatly modified version of the original W-423 Joint Plate strip that is used to attach the outboard fuel tank skin to the inboard leading edge skin. The original part provided for the joint plate is just a strip of .032 alclad aluminum about 1.5 inches wide by 36 inches long. The part thatI will need to fabricate will be a large extension of that joint plate that will resemble a letter H that is curved around the 2 leading edge ribs. This will provide the mounting platform for the outer skin assembly.
The only challenge that I have is how to form the bend for the leading edge. I do not know the exact radius that Vans uses, nor the actual procedure that they use to form the leading edge skins. While doing some research I stumbled upon some information that came from builders of the Sonex kits. It turns out that they provide a scratch build kit from plans that requires the builder to fabricate just about everything from the spars to the ribs to the skins, etc. This includes the Leading edge skins for the Sonex wings.
Apparently someone came up with a rather ingenious way to vacuum form the leading edge for the entire wing by using some 4 mil standard landscape plastic, masking tape, an 8 foot long, 2 inch diameter black schedule 40 gas pipe, some car exhaust clamps, and a standard sized shop vac. Here is a link to one of many different you tube videos I found that shows the entire process. It works quite well.
Vacuum form leading edge skin
I plan on using a similar method to bend the parts that I will need. Luckily I only have to work with a 1 foot wide piece of metal so as soon as I figure out the right diameter pipe to use I will give this a try.
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