Since I'm not installing lower winglets, I just had to fill the wing tips and shape them however I pleased. I decided to go with a sharp 90 deg edge... I liked the idea of it looking like it was cut by a laser!
So I wanted the wingtip to follow the airfoil of the wing's lower surface...
And trimmed flush with the winglet's outboard skin....
But first I needed to fill the void with foam...
If I wanted the wing tip to be flush with the airfoil's lower surface, I needed to extend the winglet wall first...
I sanded the surface so that the pour foam would bond to the fiberglass...
I taped a piece of cardboard to act like a dam to keep the pour foam from spilling over...
Also made a small dam using a card so the pour foam would not spill towards the rear...
I then mixed up X30 pour foam and poured it in...
Stuff expands quickly!!!
In 15 minutes, I ripped the cardboard off and began shaping the wingtip...
Sanded it flush with the wing's bottom surface...
And flush with the winglet's outboard skin...
The result: a clean 90 degree corner that looks like it was cut by a laser!
I sanded the winglet's outboard skin for a good glass-to-glass bond.. about 2" below the foam... painted plain epoxy on it and slurried the foam...
2 plies BID at 45.... and peel plied the transition into the winglet...
After cure, I trimmed it flush with the wing's bottom surface...
Used the dremel to make a flox corner... made sure to remove any micro that was in there. Also, sanded the wing's bottom surface (about 2") where the layup was going to overlap onto the wing.
Painted plain epoxy on the wing's bottom surface... flox into the flox corner... and slurry on the foam..
I also added flox on the aft end of the belhorn pocket.. notice how I protected the rudder cable with tape to keep it from getting flox or epoxy during the layup...
Same thing on the other wing tip...
I then prepregged 2 plies BID at 45 and placed it on top... peel plied the transition onto the wing.. and added clothes pins to the aft end of the belhorn pocket.. this helped keep the layup tight so it would cure flat..
I then trimmed the layup flush with the winglet's outboard skin...
I'm very happy with the way it turned out! Looks so sharp and clean!!
Great pic showing the internal belhorn pocket... the cable gets connected to the belhorn.. the rudder cable is then pulled as the rudder gets installed... and there you have it!! Wing tips are complete!
Although there was a flox corner between the bottom of the aft winglet and the side walls, I wanted to add a "U" layup that would wrap the bottom of the winglet.
Here's what I mean by a "U" layup... a UNI strip to wrap around the aft bottom of the winglet..
So I prepped the mating surfaces and sanded a small radius at the bottom edges to help the UNI wrap around the 90 deg corners.... painted plain epoxy and wrapped 1-ply UNI extending from the inboard wall, to the winglet bottom, to the outboard wall... then peel plied for a smooth transition...
After cure, I sanded the winglet aft trailing edge and reinstalled the rudders. I feel a lot better about the belhorn pocket, knowing that it won't delaminate with the winglet walls...
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