stunthanger.com
General control line discussion => Open Forum => Topic started by: Dennis Leonhardi on June 25, 2015, 11:49:35 AM
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Over the years, several of Chuck Felton's designs - built primarily with corrugated cardboard - have been published. A question for those who have built or seen them: Do they hold up? My gut instinct is they would be oil-soaked rags after a dozen flights, but I'm often wrong. Curious minds want to know ...
Dennis
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Balsa flys better.
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I think you could fuel-proof one well enough. I'm always turned off by the airfoil he uses, but it's probably fine for scale.
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The bellcrank mounting method is very week. Metal bellcrank mounted on plywood in two cardboard fuselage sides. Even a low pull test would pull the entire platform through the body. He did it the same way every time.
Ed
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The bellcrank mounting method is very week. Metal bellcrank mounted on plywood in two cardboard fuselage sides. Even a low pull test would pull the entire platform through the body. He did it the same way every time.
Ed
I noticed that and agree, Ed. I would want to tie the motor mounts and bellcrank platform together for sure - but even then, it's hard to see what would prevent simply pulling the bellcrank out.
Dennis
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I don't have any of his plans handy, but corrugated cardboard can be surprisingly strong. If he's gluing his bellcrank mount to the wing top, in particular, that would go a long way to making it hold.
If you're worried about it, make a plywood plate a couple of inches square and put it on the inside fuselage wall to spread the force.
Or, mock up a fuselage per the plans and pull it to destruction, and see where it pulls out. (Wear gloves!).
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Chuck uses a special type of cardboard as well. One side was white like poster board. In addition, he mentions thinning polyurethane and brushing it onto the cardboard. This goes a long way in terms of strength and fuel proofing. His designs always looked very well engineered. I really liked the Yak.
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The problem is that they also look like they're made out of cardboard. :P
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I think the models look terrific. While cardboard has some limitations, I think Chuck's methods are amazing. He's a real craftsman in my eyes. You can see some of his design work and models on the site http://www.feltondesignanddata.com/
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Here is a picture from his web site. He is very cleaver at making it work for what he wants. Scale looking models. DV^^
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I believe the gentleman designs and builds for the sport flyer that wants something almost scale. I don't think he has ever entered his designs in competition. For just general sport flying his bell crank mount is plenty. I even thought of doing s stunt plane and he stated that he didn't think I could get it light enough.
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Hi Guys,
Back in the 70's I was between jobs, in other words short on hobby money and I crashed my last plane. I saw one of the articles on cardboard building & said what the heck. So first I brushed a penetrating coat of highly thinned clear polycrilic paint on both sides of the lighest cardboard material I could find. Cardboard weight varies so pick light stock. It is easy to be picky when the price is free. When dry I re-weighed the cardboard & it added almost no weight. This is supposed preserve the cardboard against moisture. The treated cardboard is also much easier to cut cleanly than raw cardboard. The wing was 54" span & about 610 sq" with some leading edge taper & squared off tips. The airfoil was a crude slightly rounded diamond airfoil. The leading edge was folded over cardboard so it wasn't a sharp leading edge. I used a couple of full cardboard ribs & partial ribs behind the spar. I used 2 pieces of 3/16" spruce as full length spars separated by vertical fluted cardboard I use ply to re-enforce the wing center & bellcrank mount . I glued on a balsa trailing edge with 1/8th" plywood re-enforcement in the center. I cut out the cardboard sheeting top & bottom to look like a capstripped built up wing. I covered the wing with monokote. I built a prebuilt motor crutch and ply doublers & tank box & fuel proofed it. I folded the cardboard to make a simple box fuselage & used 3/16th" balsa Longerons in each corner in the rear & the prebuilt motor mount assembly in the front. I added a little ply & balsa to re-enforce fuselage around the wing & dural landing gear. The stab- elevator & rudder was just sheet cardboard edged in balsa and with lightening holes & monokoted, which slotted into the fuselage. On the fuselage I painted on more lightly thinned polycrylic as a sealer & sanded with 400 sandpaper. I sprayed on 1 light coat of white refrigerator epoxy spray paint. It weighed about 47 oz. & used strong 40 engines. It flew surprisingly well. This was supposed to be just a "temporary plane" and the thing was ugly as sin but it was tough & it endured a lot of learning & kept on going. I was trying better planes & it became my backup but fuel was adding weight and cardboard beastie was done. It was built out of my junk box of recycled & leftover stuff so I didn't really buy anything. My stupid temporary plane outlasted planes I had lavished much more time & money on while learning to stunt. Maybe there is a lesson in there somewhere, I don't know.
Pat Robinson
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The guy does good work.
A little glue, a pair of blunt tip scissors, and off you go.
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I think they could do well in AMA rules fun scale.
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He always builds them with the tank tubing coming out the top. These look just like 1955 models. Why not but both tubes ,fill and overflow out the bottom. The weights he gives are very high.