The thickness of the tip is less than 1/16″. You have to build up the edges to 1/8″ if you want to use the screws, like I do. This means that I have to apply several layers of fiberglass to the inside of the tips in order to build it up. I’m still getting the hang of this. In addition to the build up you have to put reinforcement strips onto the edge for the nutplates to attach to. I made my strips (W-728) from a recycled rudder skin. The thickness of the metal just needs to be .02, which is what the rudder is made from.
Using the Dremel I made strips that were 1/2″ wide and between 16 to 20″ long.
These will be laid down, end to end. The nutplates will be attached to these.
My first attempt at to layup to the fiberglass was pretty messy, but my second was quite a bit neater. The area I glassed is darker.
I figure it will take 3 or 4 layers to get to the 1/8″.
The flaps are pretty much done as are the ailerons. The big exception is that there will be fine tuning once the wings are on permanently. This wont be trivial fine tuning, either, but there shouldnt be any metal work to do.
Ive been avoiding the wing tips for a while. Mostly because I could. I am, though, at a place where the wingtip work will be easiest to work on now. The ailerons are done and the wings are still in their stand. Before you begin the wingtips you need to decide how they are going on. The default method is pulled rivets, the secondary method is screws and the tertiary method is with piano hinge. The piano hinge is pretty cool and leaves a super clean line and is pretty easy to remove the tip. I’m going with the screws. It isn’t as sexy as the piano hinge, but it allows you to take the tip off and on fairly easily.
To start the wingtips you need the ailerons on and set at the neutral position. When you’re completely done the wingtips will be level with the aileron when it is in a neutral position. This job will require a lot of taking the tip off and putting it back on. Lots and lots of it if you do it like me. The main reason is that the wingtip needs to be worked on quite a bit before it is final.
You are going to be done a lot of cutting and sanding of fiberglass. I chose not to do this in my garage. I set up a station in the back yard with saw horses, Dremel with a cut off wheel and a vacuum cleaner. I made sure that I had all the right safety gear on hand.
Based on my initial measurements I decided to first remove 1/16″ all around the wing tip. This would leave a nice initial fit. But! The portion of the tip from the aft edge of the aileron to the main body of the wing was not fitting at all. I ended up having to remove close to 1/2″ a little at a time so that I could sneak up on the fit. Eventually, after 3 or 4 cuttings I got the fit.
You’ll notice that there is a small gap between the aileron and the fiberglass. This is OK, but I have to increase it. The size ultimately needs to be 1/4″.I cannot change it just yet. I still may have some sanding to do for the final fit. This will change how much needs to come off from the aft of the tip. So for now I’ll concentrate on how I’m going to attach the wing tip.
I know, right? It isn’t even airborne and I have to do maintanence. I found a mistake on a rivet on the fuel tank and had to take the tank off and repair it. Like many other tasks, this one was worse while I dreaded doing it than actually doing it. All tolled…maybe 1.5hrs including the time I was watching baseball.