Shoestring (oz14863)

About this Plan

Shoestring. Radio control scale model. Wingspan 30.5 in, wing area 185 sq in, for electric power with Speed 400 motor.

Quote: "A scale backyard pylon racer. Shoestring, by Pat Tritle.

THE YELLOW AND RED SHOESTRING has always been one of my favorite airplanes and over the years, I've built several free-flight and U-control versions, all of which were great flyers. A few years ago, I started thinking about building a small RC Shoestring in a Speed 400-size. With the growing popularity of brushless motors and LiPo battery technology being what it is, I decided to forge ahead.

I designed the Shoestring so it could be built and flown by modelers with intermediate building and piloting skills while still being a good representation of the full-scale Shoestring. The result is a very stable, reasonably fast, all-sheet balsa model that's a pure ioy to fly! I've tried everything I can to make the airplane 'snap' out of a turn and determined that it just won't. Its stall is more of a 'mush' and it still maintains aileron control all the way down the speed range.

The model was designed around the 6V Speed 400 motor and is controlled by only elevator and aileron. Hand-launching is easy, as there is plenty of fuselage to hold. Landings are done 3-point, so the fixed tail-wheel keeps a good straight line during the short rollout; if you're flying onto grass, just plop it in! Though the model has a good roll rate, the aileron input isn't twitchy at the center at all, Even with the CG balance point moved aft, the elevator never gets "goosey." When the CG is moved too far aft, the model just doesn't come up on step. All in all, its a good, solid, honest airplane that I recommend to anyone who's entering the wonderful world of little airplanes.

Fuselage: As always with a model of this type, it must be built light. I built my prototype using hand-selected balsa, but using the contest-grade stuff will only help if you're really serious about building a lightweight airframe. Start by cutting and shaping the vertical and horizontal stabs. The elevator will be hinged with UltraCote after the surfaces have been covered.

Build the fuselage next. Start by cutting the fuselage sides and doublers, following the triangular marks on the plans, then, cut the formers and former doublers, assembling them as you go. Glue the doublers to the fuselage sides and add the balsa tri-stock and 1/3-inch-square balsa lower longerons. Glue formers F-3 and F-4 to the right-hand fuselage side, using a triangle to align them. Now glue the left-hand side of the fuselage to the formers. Glue the tail post pieces together and add formers F1, F2, F5 and F6 and the 1/16 x 1/8 crosspieces. Now you can add the Winch-square top stringer, 1/8 inch balsa bottom sheeting and 1/4-inch balsa chin block.

Before adding the top sheeting, be sure to install a Sullivan no. 507 guide tube for the elevator pushrod. Now is a good time to shape the balsa tail-fairing blocks and add the lite-ply landing-gear plate and balsa triangle and lite-ply wing-bolt plate..."

Direct submission to Outerzone.

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