Wing Tip Leading Edge

Making the wing tip leading edge was very challenging. The instructions were AWFUL!!! I read the paragraph many times and didn't understand it. Eventually, it began to make sense, but part of it never did become clear. Still, things worked out okay. Also, I have three more tries to perfect things. :)

 I made patterns out of poster board, then drew an outline onto the aluminum, cutting those out with tin snips. They were still a little big and so required a bit more trimming as we went.

Doing a little trimming with the Dremel. The wing tip leading edge pieces will get drilled and riveted to the piece attached to the leading edge you can see here. I cut the leading edge too short, which placed that little extension piece right over the rib. That made the leading edge stick out slightly due to its increased thickness. This is something I will definitetly get right on the other wings.

My friend Mike did a great job bending the wing tip leading edge pieces. I'll have him show me how to do it for the subsequent ones.

For the other wings, I'll have the leading edge longer as I mentioned above, thus keeping the leading edge from being thicker over the last rib (i.e., the piece of aluminum joining the leading edge and wing tip pieces will be outboard of the rib, not over it). Because of that, I don't think I'll need to put that vertical piece of fiber glass there on the other wings (the piece Mike is holding in this photo). I could be wrong, though, and might still want some fiberglass there to smooth things over. We'll see.

To hold the two wing tip leading edge pieces in place while we applied the fiberglass, we began by using some double sided tape under the metal. That didn't hold, so we applied thin strips of gaffer's tape. That was working okay until we clamped down the bottom of those pieces to the spar so they would hold that position while the epoxy cured. Then, the tops (leading edge) of those pieces pulled away a little bit. In a panic, I drilled a couple holes straight through the two pieces and put a couple screws through. After the epoxy cured, I removed the screws, then just put another layer of fiberglass over the first layer which covered up those holes just fine. Not sure what I'll do for the other ones. I'll have to think about it. This one turned out quite good, though.

We bought this fiberglass and epoxy just down the road at O'Reilly Auto Parts.

For some reason, there was space between the wing tip leading edge pieces and the spar, so I made a couple thin strips to take up that space. It turned out very nice. I epoxied them in place, then put nails through the aluminum and wood pieces into the spar. The nails and epoxy would have gone in anyway. I just added the wood filler to get a better shape with the aluminum.

The final fit of the aluminum wing tip leading edge on the spar. Very nice. Just needs a little dusting off.

A flapper disc (sand paper flaps on a wheel) made quick work of the epoxy. I also experimented with using different epoxy mixtures for fairing this area. I'll report on those later. I'm convinced (even though I'm still experimenting) that I would be MUCH better off using some softer materials (epoxies made for fairing) that sand more easily than epoxy mixtures that are so hard I need to use power tools to smooth them out. Also, I'm very inexperienced with composites, so I'm sure there are tricks to use to make this whole thing easier with better results and less work. Still, this first one is looking pretty darn good. Very nice, smooth curves.

Easy does it! Don't want to sand right through the aluminum!!!