The bare wood structure clearly shows off the spruce reinforcements. The
components are fiberglassed before being assembled.
I also found the name and email address of Margaret June’s
pilot, Kent Cassels. I sent him an email explaining that I
wanted to build a model of Margaret June, and needed some
dimensions. Although he was actually driving back home
from the Reno National Championship Air Races at the time,
I had a reply from him within about 10 minutes!
Kent included pictures, dimensions, and a scale drawing. I
was surprised and impressed, and with that I knew my project
had to be Margaret June!
My engine of choice is either the ASP S15A or the
Magnum XLS-15A. They are the same engine other than
the name on the crankcase and minor carburetor differences.
These engines are inexpensive and start easily, even in the
hands of a novice.
The ASP is available from HobbyPartz.com for less than
$45. The slightly more-expensive Magnum is available from
Tower Hobbies and Hobby People.
The stock engine must be used, except for the venturi and
spraybar. I can provide venturis and needle assemblies for $10
each or $20 for both (contact me at the email at the end of
this article), although anything that meets the rules may be
Let’s get started!
Throughout the airplane build, I tried to use standard
hobby shop parts and supplies as much as possible. If your
preferences are different, feel free to use what you like. The
recommended construction sequence may seem to jump
around, but will make sense after reading through the text.
Begin by cutting out the forward part of the
wing and wingtips from 3/8-inch medium-hard
balsa. Cut the rear portion of the wing from
3/8-inch medium-light balsa. Cut the bellcrank
mount from 3/8 x 1/2-inch maple engine-mount
Notch the rear portion of the wing to fit the bellcrank
mount. Assemble all parts of the wing, including the
spruce spar and leading and trailing edges.
Throughout the airplane, wherever spruce is called
out, basswood may also be used. If you can’t find spruce
or basswood longer than 24 inches, the wing spar can be
spliced in the center.
When it has dried, taper the wing’s thickness from 3/8 inch
at the center to approximately 1/4 inch at the tips, leaving
the bottom of the wing flat. Carve and sand the wing to the
airfoil shown on the plans. If you prefer a different airfoil, use
whatever you like, but the flat bottom works fine and is the
Drill a hole for the 6-32 bellcrank mounting bolt. Recess
the top of the bellcrank mount so that a 6-32 blind nut will
sit flush with the top of the wing, and install the blind nut.
Add 1/2 ounce of tip weight to the outboard wing, give the
wing a final sanding, and put it aside.
A word of caution: pay attention to the bellcrank mount as
you work on the wing. It is not symmetrical, and it would be
easy to build the wing upside down.
You will need the landing gear while working on the
fuselage, so make it at this time. The landing gear can be
made from a Great Planes Dural L- 1 aluminum landing gear
(#GPMQ1810), available from the hobby shop or Tower
Hobbies. Measure 43/8 inches from the bottom of the gear
(measure as if the gear were flat instead of bent) and cut off
the gear legs. Bend each gear 1 inch from the top to make a
matched left and right pair. Alternately, the gear can be cut
from 3/32-inch sheet aluminum. Tap the outboard gear 4-40
and clearance drill the inboard gear for the 4-40 bolts that will
hold it on. The gear can be tapered, sanded, and polished as
The 11/4-inch Williams Brothers (#13800) wheels are
available from the hobby shop or Tower Hobbies. Use 6-32
x 11/2-inch Great Planes bolts for the axles (#GPMQ3042).
These were chosen because the unthreaded portion of the bolt
is an appropriate length for the thickness of the wheel. Drill
the wheels to spin freely on the bolts. Use a washer on each
side of the wheel and attach to the gear with a 6-32 hex nut
on each side of the gear. Be sure to use Loctite. Cut off any
excess bolt length.
For a sleeker installation, get some 1/4-inch outside
diameter x 7/16-inch threaded standoffs from McMaster-Carr
(#92474A264). Drill the wheels out to 1/4-inch inside diameter.
Using Loctite, install the wheels and axles with 6-32 x 1/4-inch
button-head screws and washers. Alternately, standard RC-type
bolt-on axles and wheel collars can also be used.
Engine Mounting Plate
The engine should be mounted on a 1/16 to 1/8-inch thick
aluminum plate or pads. If you used the L- 1 landing gear,
the pads can be cut from the leftover aluminum. Cut them
approximately 3/8 x 11/4 inches. The plans show a pattern for a
one-piece plate. Drill the plate to fit the engine. Drill holes for
the #2 sheet-metal screws that will hold the plate in place.
Cut out the fuselage top and bottom from 3/8-inch medium-hard balsa, but don’t make the cuts for the maple mounts yet.
33 Model Aviation JUNE 2015 www.ModelAviation.com