BY PAT TRITLE
PLAN IN THIS ISSUE!
A scale backyard pylon racer
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 joy 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
BUILDING THE 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
The Shoestring fuselage is fairly easy to assemble.
The tail surfaces are sheet balsa. The elevator is
hinged with UltraCote after the tail pieces have
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 tailwheel 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, it’s a good, solid, honest airplane
that I recommend to anyone who’s entering the wonderful world of little airplanes.
Use the battery as ballast to properly adjust the
CG. The battery is held in place with Velcro.
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 1⁄8-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 Fl, F2, F5 and F6
and the 1⁄16x1⁄8-inch crosspieces. Now you
can add the 1⁄8-inch-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. Using a