Bill Weaver had an O.S. . 40 engine that reminded him of days gone by when airplanes sported 40 to
65 hp Continental flat-four engines and
flew off grass flying fields. He felt that
the O.S. was destined to be used in a
graceful, slow-flying antique model.
It occurred to Bill that the perfect
synthesis would be to build an airplane
that was appropriate to the four-cycle
sound, and looked real. The Henderson
Longster, a 1933 home-built, came to
mind. He found a 1933 Flying Manual,
republished by EAA, and scaled his
prototype from the plans, dimensions,
photos, and text in the manual.
The 1/4-scale model had a 71/2-foot
wingspan and weighed slightly less than
6 pounds. It duplicated the structure of
the full-scale Longster except for the use
of model airplane materials, balsa blocks
enclosing the hinges, model engine
mounting, the method of attaching
the wings at the center section, and
provisions for RC equipment.
The wing, aileron, and tail were
primarily balsa. Ambroid was used for
strength on the wood frame fuselage for
tension leads. The engine fuel tank and
the seal around the hole for the engine
servo lead where it passed through the
engine mount plywood were attached
with GE Silicone II Household Glue and
Landing gear parts were built and
assembled on the fuselage. Rigging and
control wires were 0.27-inch diameter
stainless steel CL cables. The model was
completed and rigged before the RC
equipment was installed.
Bill covered the prototype Longster
with Permagloss Coverite in silver,
with red Aerogloss Stearman for trim.
Numbers were cut from black Coverite
Graphic Trim Sheets, slid into place
with soapy water, and rubbed down.
Excess weight from the engine, covering,
etc., could be compensated for by
substituting 800 or 500 mAh batteries
for the 1, 100 mAh batteries used, while
lead could be added before installing the
batteries if it was tail-heavy.
The Longster called for many
materials in relatively uncommon sizes,
but Bill noted that a modeler shouldn’t
worry if the local hobby shop didn’t
stock the necessary material. The
aluminum sheet, hex screws and nuts,
and wood screws could be ordered from
The Longster was a slow, stable flier
that could make deliberate scalelike
loops, rolls, and slips. Bill stated that with
a wing loading of 12. 5 ounces/square
foot with the O.S. . 40, it flew well. “The
smooth takeoffs from grass and efficient
climbouts exemplify the low power
requirement by an airplane flying on a
lightly loaded wing,” he said.
The model’s only disadvantage was
that it would not stand up to winds
greater than 15 mph, unlike the full-scale aircraft which could handle
equivalent 60 mph winds.
Featured in the June 1989 MA and
listed as AMA Plans Service number
623, the Henderson Longster is available
for $24 plus shipping and handling.
AMA members can access the MA
Digital Library on the magazine’s
website to read more about the
Longster. See page 155 or go to www.
modelaircraft.org/plans.aspx for ordering
The Henderson Longster replicates
the full-scale aircraft
105 Model Aviation SEP TEMBER 2014 www.ModelAviation.com