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Old 01-11-2009, 12:21 AM
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Willja67 Willja67 is offline
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1/8 scale Foam RC model (card model inspired)

My dad won a RC plane back in 1989 but after putting in a few hours on it never did anything else. About 9 years later I did some work on it, then let it sit for another 9 years or so before I finally decided it needed to be finished and did it. Then it sat for another 2 years before I finally ran into a guy who was into RC aircraft and I asked him to help me fly it.

Long story short I got a little more interested in RC aviation since then and came up with an interesting application of card modeling principles. I came up with the idea of using a hotwire foam cutter (not very original I know) to cut out the sections of fuselage out of blocks of foam by tacking the formers from paper model kits to either end.

I am currently designing a airplane I one day hope to build and fly (1:1 scale). I think I posted something about over on the Z place. Anyhow it's a small single engine elliptical inverted gull wing hot rod. I am building a 1/8 scale model of it and here is what I have so far.

The first pic is part of a sheet of 2 in thick foam insulation purchased at Lowes, the second shows a hotwire cutter I bought at a local hobby shop with a template of the front half of a wing section (remember elliptical so I have to segmet it) the third shows the main spar combined with the fuselage former at that station (1/16" plywood) along with the outer main spar (1/16" basswood) and the sections of foam that I have cut glued in place. The fourth is a somewhat dated Rhino screen capture of the aircraft. There have been some design changes to the design since then, mainly the lengthening of the tail and enlargement of the tail surfaces to promote better stability.

I was in the hobbyshop earlier today and they had some glue specially made for joining foam together but like a dummy I decided to wait. I needed it to glue 2 layers of foam together so it would be thick enough to cut fuselage parts out of. But I can still cut out the wings. The hotwire cutter has no temp control on it and it gets really hot really quick so if you dilly dally cutting it will melt a large swath and ruin the part. If I gave a closeup of the leading edge sections cut so far you could see how they improve as I've learned a little better technique. Still not very good but these are probably just test pieces for now.

I am not sure yet if I will use a balsa leading edge ( I will definately use balsa on the trailing edge) hence the section with the leading edge cut back. That's it for now.
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1/8 scale Foam RC model (card model inspired)-000_0229.jpg   1/8 scale Foam RC model (card model inspired)-000_0230.jpg   1/8 scale Foam RC model (card model inspired)-000_0231.jpg   1/8 scale Foam RC model (card model inspired)-frontleft.jpg  
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Paper model designer turned aircraft designer.

My models available for sale @ Gremir and Ecardmodels
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