Using the cockpit for a hatch. To me, It's easier to pop off the canopy than to take off the wing when replacing batteries. This is one way to do it. There are many ways you could go and as long as the canopy stays in place, I guess each one is correct . So, some 1/8 hardwood dowel, some 1/16 scrap plywood, some rare earth magnets, 4 drywall screws, cardboard and epoxy.
Pic 1. Make a cardboard template and mark it where two dowels will go. when I have tried to drill foam a 1/8 hole always seems to end up 3/16. Pic2. My way around it is to heat up the back end of the drill bit. Align it with the template and push it into the foam. when the bit is the right temp, it will usually go in about a 1/2 inch. If the hole has to be deeper, reheat the bit and push it into the foam. Pic 3. Two nice round 1/8 holes that the dowels slide into. Pic 4. Experiment on the same type of foam that you want to put the hole in. The far right hole is about 1/4 inch. The 1/8 bit is way too hot. The next two holes, the bit is cooler but still too hot. The last on the left, the temp is correct and the bit leaves a 1/8 hole. With my propane torch, the count of three is about long enough for the correct temp. Larger bit, longer in the flame. Cut two pieces of 1/16 ply to size and drill 1/8 holes in each. Use 1/8 dowel and insert it through the ply and into the foam. Mark the profile of the ply onto the foam. Recess the foam so that the ply sits flush. Glue the ply in place using the dowel to align the ply and the foam. The ply is not for strength, it is used as a wear block. With out it, the hole in the foam would be the size of a pencil in no time. Put the template on the cockpit side and use the hot drill bit to make the holes. Take off the template and glue in two 1/8 dowels cut to length.
Pic 5. The bottom back side of the cockpit marked out so that the hot wire cutter can remove the foam so that the magnets can be installed. Pic 6. Magnets epoxied in place.
I'll clean up the glue before I fiber glass the area. Pic 7. Drywall screws installed so that the magnets have something to stick to. Pic 8. Template made and attached to the back of the cockpit and centering dowel glued in place. Pic 9. Template used again to mark dowel position on fuselage. Pic 10. Again we need a wear plate. I put the canopy on and pushed it into place until the dowel made contact with the foam. This told me how tall the wear plate had to be. Cut the ply to size, drilled 1/8 hole to match hole in fuselage. Then cut a 1/8 slot to the top of the plate. Used the hot wire cutter to remove foam from the fuselage so that the wear plate sat flush with the foam. Glued the plate in place. Put the cockpit in place and the dowel touched the foam at the top of the slot. Pushed the cockpit up and down 2 or 3 times and the dowel made it's own channel in the foam. There is also a nice healthy snap when the magnets lock onto the drywall screws.
The actual build is complete. Now it's on to prep for paint. With the cold weather on the way I may not get it prepped before it's too cold for painting. My spray both is the back yard. It may be a while between posts now. It won't be because I gave up, but because I'm waiting for warm weather to paint.
Don
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