The classic Twin Comanche tip tanks add to the 'COOL' of the aircraft and I would never consider leaving them off the build. Sure they are just extra weight but I justify them because they are aerodynamic and I'm confident they produce some lift. I've cut a ply rib to mate with the wing outer rib and the tank is built onto that rib.
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Basically, I've just built a a box with 1/2 inch balsa. The sides were cut to the approximate shape of the tanks. balsa blocks added for the nose and tail. It was then a case of carving and sanding until I was satisfied with the shape. The centre hole is for the nav light wiring.
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Once the Tanks are fitted, the wing can't belong to anything other than a Comanche.
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