FT Simple Cub

One of my all time favorite planes is the J-3 Piper Cub. Even though I don’t have my pilots license (yet…), I hope that one day I’ll be behind the controls of a real one. For now I satisfy my dreams of flying with RC Planes.

The Plans

Anyone who has any interest in model aviation needs to check out FliteTest. Whether you’re a beginner or advanced, they take scratch building to a whole new level. I truly love these guys and and can’t thank them enough for all their hard work. Not only do they provide free plans and step-by-step build videos for all their models, but you can support them by buying laser cut speed-build kits and hardware. They can all be built with common materials you find at the dollar store like foam boards, barbecue skewers, tape, and hot glue. I’ve purchased a few kits from them before (FT Sparrow, FT Versa Wing), but for this build I opted to print and cut them out.

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In hindsight this was a major PITA… Printing the tiled plans, cutting and taping the pages to the full size, using pins and a pencil to transfer the plan to the foam board, and then cutting out each piece with an x-acto blade. You can however take the pieces and trace them onto another board to save you a bunch of time if you are building more than one. For small planes like the FT Sparrow (my EDC plane), this is more realistic with very few parts to cut out. However the $15-$30 laser-cut waterproof foam board kits are worth it and even come with some extra hardware like the plywood firewall, steel wire for the control surfaces, etc.

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Fluffing the Tail Feathers

Paint

From my past experiences, I’ve had a lot of success with covering foam board with colored tape for finishing. This adds extra strength/durability and is also less of a health hazard than painting with rattle cans. Again I strayed from my norm and went with Valspar paint and Polyurethane for covering and waterproofing.

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Decals

I was also fortunate to have a friend who had access to a plotter to cut some vinyl decals for finishing. Using the plans as a template, I created the window, number, and stripe decals in Illustrator. This was actually a new experience for me, and I learned a lot about decals, weeding, and transfer paper. The tiny cub decal on the tail was simply printed on letter paper, glued on, and then finished with a little polyurethane.

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Engine

A realistic piper wouldn’t be complete without a few 3D Printed parts to finish it off. This was probably the most time consuming part but absolutely the most satisfying. I had trouble finding a decent mock engine model that met my needs so I fired up Fusion 360. It’s far from accurate compared to the real thing, but it looks scale enough and has a large flat surface for gluing to the foam board. Even the tiny bolt heads came out in the print with my FDM 3D printer and a 0.2mm layer height. A bit of sanding to remove the stair-step print lines on the duct and a quick coat of some old acrylic paints made the finishing touch (if you aren’t looking too closely…). Now having a giant air scoop with nowhere for the air to go will definitely create unnecessary drag and might even rip them off in the propeller wash. You could either drill a large hole in the flat area and the foam of your body to make them functional and help cool the ESC, or just fill the scoop with something like hot glue or clay (especially if you need the extra nose weight). The model below provides the option for both. If you go the functional route, I’d suggest locating the hole towards the back, leaving plenty of surface area to attach it towards the front. I’d also suggest using something like epoxy rather than hot glue, and remove the outer layer of paper from the foam before gluing, to prevent it from delaminating and pulling your nice paint and artwork with it.

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Finished Airplane

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