Here is a fairly unique
free flight rubber model named the "Scotch Monoped" partly due to its having
a single wheel and partly due to its designer being of Scottish heritage. It
is of simple stick and tissue construction, and full-sized planes were
published in the December 1939 issue of Flying Aces magazine.
"Scotty" Mayors says he made it inherently stable under all conditions by
providing lots of side area in the fuselage and dual vertical fins. The
airfoil is a rather thick flat-bottomed section. A look at the open
framework reveals that minimum weight was a goal, since even the wing ribs
have lightening holes cut in them. I forgot to scan the wing plan sheet
and will do so. If you read this before I get around to it and need the wing
plans, send me an e-mail and I'll get right on it.
The "Scotch Monoped" - Article & Plans
One quick glance at this photo is all you need to tell that "Scotty's"
job is tops. For this skeleton shot clearly shows all of the construction details.
By "Scotty" Mayors
Designer of "Kiltie, "Gull Biplane," etc.
We've seen many a one-wheeler in our time, but have never come across one that's
as perfect in every detail as this little buggy of "Scotty" Mayors'. Yes, lads,
she's got everything that modelers dream about after a good dose of dope -
andcementmixedwiththinner - or whatever
it is that the medicos jot down in their Latin lingo. But we promise you that this
one-legged pretty will chase all of the blues from your system.
So get set to build -
Being a somewhat canny Scot, my heart was warmed immensely by the thought of
the materials, time, money, and labor that would be saved by building a monoped.
Hoot Mon! Imagine! Only one wheel, one pant, one landing gear leg, one prop, one
wing, one fuselage, and one stabilizer.
Alas, it went deeply against my nature to add two rudders, but consolation in
the fact that they would balance the plane on the ground and help directional stability
in the air eased my conscience.
With her prop turning over full-blast, the "Monoped" is all set
to soar into the skies on a top-notch flight! And note that gentle dihedral angle
to the wing, the sleek color markings, and how the rubber loops go clear around
the fuselage. To make your model just as swell as this one, follow the plans carefully.
Now hop to it!
In this revealing three-quarter rear shot, you can see just what
our "Monoped" will look like as she rolls down the runway for a take-off. Look closely,
fellow modelers, and you'll see the rear-hook in the aft section of the fuselage.
That cut-out section is for easy accessibility in case your rubber decides to break.
However, not wishing to be too tight, I allowed a fair amount of fin and side
area, as was needed, making the model inherently stable in all maneuvers, and easily
controlled and flown by the novice as well as the veteran. (And that's the gospel
truth, too. But if you doubt me for even a moment, then just stop right here and
take a good look at the plans before you go any further.)
The model abounds -in standard-size wood, no fancy or hard-to-get pieces being
used. Provision has been made for easy assembly, all surfaces, including nose-block
and landing-gear, having been cut to fit some part of the fuselage.
Experiments with a single ski instead of a wheel to be used during the winter
should indeed prove interesting. So, unsheathe your trusty razor, gather your materials,
and build the Scotsman's delight - a monoped!
Building the Body
The fuselage is constructed entirely of 3/32" sq. and 1/16" flat balsa. Build
two sides, as shown by the heavy outline. Connect the top and bottom by cross-pieces
of 3/32" sq. You will now have a box-like structure upon which to glue the formers,
which are cut from 1/16" flat. Note that the formers "1" and "2," "1B" and "2B"
are double - that is, two pieces of 1/6" flat are cut and laminated to provide the
The "keel" fits between former "2B" and the bottom of the fuselage structure.
It is cut from 1/16" flat. The cut-outs in the formers provide space for the stringers,
which are 3/32" sq. Gussets at the tail-end of the fuselage are cut from 1/16" flat
and glued in position.
Cross-grain two pieces of 1/16" flat to form the rear hook plug, as shown. No.
12 wire is bent to shape and anchored in the wood. Use plenty of glue to keep both
plug and hook in position.
Cut and shape the nose-block from a block of balsa 2 1/4" by 1 1/4" by 1". The
back of the block conforms to the shape of the front of the fuselage structure.
A piece of 1/4" sq. balsa, glued to the back of the nose-block, will serve as a
plug, to be inserted in the box-like structure between formers "1" and "1B." The
nose is now pierced for the prop shaft, eyelets being glued on the front and rear
of the block.
Landing Gear and Tail
One landing gear leg, cut from 3 pieces of 1/16" flat balsa, and laminated, may
now be made. The cut-out in the middle piece assures a perfect fit on the "keel"
of the fuselage. The single pant is cut from 6 pieces of 1/16" flat, the 4 center
pieces having cut-outs to allow the wheel to roll smoothly. Sandpaper the pant to
a streamline shape, as should also be done to the landing gear leg.
A wheel of 1 1/4" diameter is mounted in the pant on an axle of No. 12 wire.
Eyelets on each side of the pant will prevent the wire from cutting the wood.
Now glue the landing gear leg to the top of the pant. A ridge of glue is advisable
where the two parts meet. Glue this unit now to the "keel" between formers "2B"
and "3B." The pieces marked "S" are glued to each side of the landing gear leg after
it has been glued to the "keel." This makes for strength and easy covering.
Tail surfaces should now be built. The stabilizer is constructed of 3/32" sq.
with a 1/16" flat trailing edge flap. Round off the leading and trailing edges with
sandpaper. Two rudders are built of 3/32" sq. and 1/16" flat as shown. Each rudder
may be cut from a single piece of 1/16" flat, the center cut out, and the 3/32"
braces glued in place. Sandpaper to a smooth finish. A thin wire skid is cemented
to the underside of each rudder to prevent wear on the wood when contact with the
ground is made.
To Make the Wing
Cut 16 ribs from 1/16" flat, carving where necessary to provide for the leading
and trailing edge and spars. The size of spars, etc., is given on the drawing. Cut
the wingtips to shape and glue in position.
To create the dihedral it is best to crack the spars, leading and trailing edges,
just to the outside of the center-section, then glue the cracks solidly to provide
the 2" dihedral angle on each side. The curved trailing edge at the center-section
narrows the wing so that it may be moved on top of the fuselage with no difficulty.
A block, preferably of hard balsa, 8" by 1 1/2" by 3/4", is cut to form the prop.
Keep the blade section thick, especially near the hub, as one well carved prop is
better than a couple of thin toothpicks that break when sneezed at. Pierce a hole
in the airscrew to take the prop shaft. And be doubly certain that your prop is
Paper cut in panels and strips, glued to the fuselage with banana oil or heavy
dope, will facilitate covering. Tail surfaces may be covered with one large piece
for each side.
The wing is covered with large panels of tissue, with the grain running lengthwise.
Separate pieces are used to cover the wingtips and center-section. Only the first
and end rib should be used on the top of the wing for the adherence of the paper,
as well as the leading and trailing edge. And the bottom of the wing must be covered
by doping the paper to every rib and the spars, in order to maintain the true curvature
of the airfoil section.
The cut-and-try method is used to cover the cabin and windshield with cellophane.
Window outlines may be painted in, the color being left to the model builder's choice.
Glue the rudders onto the tips of the stabilizer in their respective positions.
Alignment becomes very important at this phase of assembly, as both rudders must
be facing straight ahead, with no deviation from the center line. This unit is now
glued to the rear of the fuselage in the position shown. No angle of incidence is
used, although there is enough room to provide a slight amount of negative or positive
incidence, should this be necessary.
The top of the fuselage assures a positive incidence for the wing. Small blocks
under the leading edge will increase the incidence. No more than 3 degrees - about
3/16" - should be used.
Nine feet of 1/8" flat rubber should be connected between the prop shaft and
the rear hook. Cover the hooks with rubber tubing to prevent cutting the rubber
The covering should now be sprayed with water to tighten the paper. Two coats
of light dope are then applied with a brush or spray.
My own personal markings and color scheme are yellow with a contrasting blue
scalloped prop and nose-block. License numbers, lettering, and insignia are left
to your imagination and ingenuity.
Flying the Model
After attaching the 8 strand motor with an "S" hook, try gliding the ship over
a smooth landing area, so that you may observe the angle at which she hits the ground.
The model should land tail high, gradually settling until the one wheel and two
tail skids roll along the ground. Warping the flap at the trailing edge can be used
to affect the glide somewhat.
During test flights, the Monoped was flown with torque (to the left), and counter
torque (to the right). The model climbs rather steeply in either direction, levels
out after a 30 second motor run, then floats in very nicely to a "one point landing,"
settling slowly to the tail skids without the slightest tendency to "wing over"
or ground loop.
Take-offs are fast, as the plane rolls very easily. And no trouble was encountered,
due to the single landing wheel. Nose-overs, even in rough ground, were few, due
to the forward position of the wheel.
Rather than predict duration flights, which are usually due to thermal currents,
I should like to state that the ship gives the builder a chance to experiment in
variety flights - that is, to fly the model in any direction he so pleases, without
having to be concerned with the thought of a wrecked craft, due to directional instability,
spins, or hot landings.
And with just a wee bit o' adjustment to the tails and stabilizer "flap," the
Monoped might even fly to the land of the bagpipes and heather. Hoot, and she's
Monoped Plans (sheet 1)
Monoped Plans (sheet 2)
Bill of Materials
(Get these supplies for your "Monoped")
Eighteen strips 3/32" sq. by 18" medium balsa for fuselage, stabilizer, rudders,
Four sheets 1/16" by 2" by 18" medium balsa for formers, tips, landing gear,
keel, and ribs;
One strip 1/4" sq. by 36" medium balsa for leading edge;
One strip 3/16" by 1/16" by 36" medium balsa for spar;
One block 8" by 1 1/2" by 3/4" hard balsa for prop;
One block 2 1/4" by 1 1/4" by 1" medium balsa for nose-block;
One wheel 1 1/4" diameter, glue, banana oil, dope, tissue, eyelets, washers,
No. 12 wire, 10 feet of 1/8" flat rubber, cellophane, sandpaper, etc.
The AMA Plans Service offers a
full-size version of many of the plans show here at a very reasonable cost. They
will scale the plans any size for you. It is always best to buy printed plans because
my scanner versions often have distortions that can cause parts to fit poorly. Purchasing
plans also help to support the operation of the
Academy of Model Aeronautics - the #1
advocate for model aviation throughout the world. If the AMA no longer has this
plan on file, I will be glad to send you my higher resolution version.
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Posted May 22, 2021