Nesmith Cougar Article & Plans
April 1971 American Aircraft Modeler
April 1971 American Aircraft Modeler
[Table of Contents]
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article and plans for the Nesmith Cougar homebuilt plane appeared in the
April 1971 edition of American Aircraft Modeler. Per
"The Nesmith Cougar was a light aircraft developed in the United States
in the 1950s and marketed for homebuilding. The design, by Robert Nesmith,
was for a conventional high-wing, strut-braced monoplane with fixed tailwheel
undercarriage. The pilot and a single passenger were seated side-by-side.
The fuselage and empennage were of welded steel-tube construction, while
the wings were of wood, and the whole aircraft was fabric-covered."
simple lines make this aircraft an ideal beginner's scale ship. With lots
of detail, is is a contest winner.
It's a rare homebuilt aircraft
magazine that doesn't include a Nesmith Cougar. With a wingspan of 20 ft.
5 in., the Cougar zips along, powered. by an 85-hp air-cooled Continental
engine or by a higher-powered 115-hp Lycoming engine. With an empty weight
of 624 lb., this ship can cruise at 166 mph; its maximum speed is around
182 mph, Service ceiling is 13,000 ft. and the takeoff run is- 310 ft. (solo).
Cougars have been built with fiberglass wings or wheel pants, with
various cowling styles, and a few without the rear side windows. One Cougar
even had folding wings for storage and towing by an auto. Any of these features
may be incorporated in the model.
Author holding his finely-detailed Cougar. The high. gloss finish with
MonoKote is suitable for homebuilt designs; some real planes are this
glossy. Photos by Tom Alerida.
The Cougar is something of a fast-flying box. Its angular design detracts
only mildly from performance but aids greatly in construction.
Many full-size planes are built and flown.
My Cougar was built in Spring of 1969, when I decided to attend the
Nationals at Willow Grove, Penna. With only seven weeks of building time,
I wanted a ship with simple, yet unusual lines, and the Cougar satisfied
these requirements. The ship's maiden flight at the Nats was rather precarious
because the windshield blew off, but the Cougar has placed in every air
meet since the Nats, including the Eastern States championships held at
Johnsville Naval Air Station. It really doesn't take a huge, multi-engine
scale ship to bring the hardware home, as was quite evident at the 1969
Nats. The building of small, single-engined scale ships is on the increase.
The amount of detailing is
left to the builder's discretion. Throttle control, operating landing lights,
navigation lights, an operating door, complete interior and workable controls
from the control stick are a few of the point-gathering features that may
be incorporated in the Cougar.
Construction by the usual stick and
tissue method is not difficult. The fuselage is a simple box affair. Its
sides are made from "1/4" sq. medium hard balsa, except for the four upright
pieces in the cabin area which extend into the plywood wing center section
C1. These four pieces are of "1/4" sq. hardwood.
Build one side
directly on the plans. When dry, build the other side on top of the first
side to make them identical. A sheet of wax paper should be laid on the
first side after it is dry and before starting the second side. This prevents
the two sides from being accidentally glued together. Use pins to hold the
second side down while gluing and assembling.
When the second side
is finished, remove both assemblies from the plans and separate, being careful
not to break any of the glued joints. Drill three holes for the leadout
control line wire grommets at the top of the cabin on the left fuselage
side. Glue the 3/32" plywood nose pieces so that they are on the inside
when the fuselage sides are held upright. Join the sides together at the
rear and add the 1/4" sq. cross members on the nose.
fuselage framework by adding all the crosspieces except the two directly
below the two directly bwlow the engine compartment. Take the carved balsa
tail piece and glue the tail wheel landing gear wire to it. Use gauze to
strengthen this area if necessary. Next, glue the tail piece, with the tail
wheel wire to the end of the fuselage sides. Add "the nose pieces and "1/4"
plywood stabilizer mount, S1. Use a triangle to keep the sides a true 90
degrees from the crossmembers. It is quite easy to make a lop-sided fuselage.
Slide fuselage plywood formers F1 and F2 onto the motor mounts which
have been drilled for the engine. I would recommend a 35 displacement engine
for flying in windy weather or off grass. For flying off macadam or concrete,
a 19 should handle the ship with ease, providing construction is kept light,
and no flying is done in wind. My ship, with a Max O.S. 35, is quite stable
in a moderate wind.
Mount the landing gear, using J bolts. When
the engine mounts and the landing gear are lined up, solder the two landing
gear pieces. Use either 3/32" or 1/8" dia. music wire for the landing gear.
For a 35 engine, use 1/8" dia. wire.
Glue the two fuel tank mounts
to the engine mounts after positioning the plywood formers to accommodate
the engine and fuel tank. Secure the plywood formers F1 and F2 with ample
amounts of cement. Glue the fuel tank to the tank mounts. Use fine wire,
if necessary, but be sure the fuel tank is mounted securely. I used a wedge-shaped
fuel tank, but a rectangular tank will do. Be sure the landing gear J bolts
do not interfere with the tank. If they do, make the hardwood tank mounts
thicker in height in order to drop the fuel tank to clear the J bolts.
Allow the fuselage to dry thoroughly for several days before any
Carving the leading edge from 5/8" balsa is the
most difficult task in the construction. Pin the 1/4" trailing edge, the
leading edge, and W1 and W2 to the plane. Then glue the 1/16 x 1/8" bottom
cap-stripping in place. Notch the 1/4" sq. hard balsa spar to accept W2
and glue in place. When dry, glue in the wing ribs. Next add the top cap
strips. Cap-stripping may require a little more time than usual, but it
pays off when the ship is covered. Add two wing strut mounts and set the
wing aside to dry.
Stabilizer and tail are made from 3/8" balsa
or two 3/16" sheets glued together. Sand to the airfoil shown on the plans.
Use elevator hinges of your choice and then attach the control horn.
When the fuselage is dry, sand the outside edges of the four longerons
round to resemble tubing when the covering is applied.
stabilizer to the rear of the fuselage as shown and, when dry, drill two
1/8" dia. holes through the stabilizer and S1. Then drill two 1/8" holes
in the bottom of the tail. Mount the tail to the stabilizer, using 1/8"
dowel, and glue securely. This makes quite a sturdy tail section.
The fuselage side fairings and bottom fairings are added at this time.
Cut down a Roberts three-line bell-crank and bolt to the bottom
of plywood W2 on the wing. Bolt the engine in place and wrap it in aluminum
foil until the ship is completed.
The real Cougar has only a one-inch
dihedral. This may be eliminated on the model and it still will be an excellent
flyer. I used a 1/4-in. dihedral on each wing panel. Glue the plywood leadout
guide in place.
Lay the wing on top of the fuselage and allow the
1/4" sq. hardwood uprights of the fuselage to come through the corresponding
cutouts on the center wing section W1 and W2. Do not glue as yet, but pin
the wing in place and cut and bend the necessary push rods and throttle
linkage to shape. When these are fitted and work freely without binding,
glue the wing in position. Be generous with the glue, some of the pull tests
at certain contests are unbelievable! While the glue is drying, make the
wing struts. They can be made from a solid strip of wood, but I prefer to
use a laminated strut of two pieces. This permits an easier installation
of the fittings, which are made from brass, aluminum, or any available scrap
Attach overflow and refill fuel lines to the fuel tank. A
realistic refill tube can be made from the upper portion of an exhausted
Pactra Plastic Balsa tube. The refill fuel line is brought from the fuel
tank, and through the threaded portion of the Plastic Balsa tube. Allow
only several threads to project beyond the 1/16" sheet balsa cowl covering.
After refueling, merely screw the cap back on. This should bring a few extra
scale points. Use hard 1/16" sheet balsa to cover the cowl section, top
and bottom. These sections may be hinged to allow access to the engine.
The air scoop is built up from 1/16" balsa.
The interior may be
simple or plush, but it is the interior detailing which often makes or breaks
a scale ship. Plans show a typical interior. Seats may be carved from balsa
and covered with vinyl, corduroy, thin leather or just about any realistic
material. Small diameter aluminum tubing or dowel may be used for the seat
framing. Build a floor from hard 1/16" balsa. The pedal tubing can be made
in the same manner as the seat frame.
I used Tatone's instrument
gauges which make a handsome instrument panel. The panel is made from 1/16"
plywood with holes drilled to accept Tatone instruments. The instrument
deck covering is made from 1/32" balsa can be covered to match the interior.
I used black #400 wet or dry sandpaper.
Glue the 3/16" sq. hardwood
windshield frame posts in place. These posts and other bare wood areas in
the cabin should be painted. Put in floor carpeting if desired and mount
the control sticks. Seat belts and a map or two on the seat add a touch
Complete the framework by gluing FC1 and FC2 into position.
Carefully sand the entire framework. The smoother the framework, the better
the covering job will be.
The model is now ready for its skin. I
completed my Cougars' framework only one week before the Nationals. Since
it was impossible to cover the ship with Silkspan and dope in that amount
of time, I decided to try the new Super MonoKote. I was well pleased with
the results and the entire ship was covered in two evenings. Metallic Green
MonoKote was used and the tail surfaces and ailerons were painted white
with matching interior. Side trim was cut from silver decal sheet and red
craft tape used for trim.
Other details to be added now are the
aluminum tubing used for the windshield braces which are glued in the correct
position, directly behind the windshield. Mount the leadout eyelets, three
on the left fuselage and three on the leadout guide. These are cut down
from Perfect No. 214 leadout eyelets. Bring the leadout wires through the
Cut windshield and side windows oversize and trim to fit.
Contact cement may be used to attach these in place. I used red and white
tape for the window trim. The windshield center post is glued on the outside
of the windshield and may be made from thin scrap aluminum.
registration numbers on my model's wing are incomplete because the set was
incomplete. This error wasn't detected until 1:30 a.m., as I added details
on the deadline day for judging (sound familiar?). The color scheme is left
entirely to the builder. A quick glance through any aviation magazine provides
many ideas. A back issue of Air Progress has an excellent set of plans for
the Cougar by Triggs.
Complete the ship by mounting ailerons and
pitot tube. Offset the rudder and mount the wing struts.
Cougar will practically fly itself. Allow the model at least half a lap
to gain flying speed before applying a small amount of up elevator to move
the model from the ground.
Nesmith Cougar Plans
<click for larger version>
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Posted September 8, 2012
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