Here is a really
nicely done Curtiss Pusher biplane model for control line. The original model had a 24" wingspan and was powered by
an .049 ignition engine, but you could easily adapt it to electric power. In fact, doing so would eliminate the
hassle of needing to hinge the tail boom and empennage for accommodations easier engine starting. If you elect to
build the Curtiss Pusher, be prepared to do a lot of work because of the shaped wood sticks for the fuselage, the
undercambered airfoil (which could be modified to flat bottom airfoil for simplicity in
covering), and the flying wire rigging. It does make a great looking subject, to be sure.
By Henry Struck
in the days when airplanes were "flying machines" and jets were gas-light burners, Lincoln Beachey amazed America with
his incomparable precision flying and stunting. He was the first to power dive and zoom, whip stall and spiral, as well
as the first American to fly inverted and loop. To demonstrate the ease and precision with which he could control his
Curtiss "Tripod" pusher, Beachey flew for miles up and down Chicago boulevards, skimming the tops of autos and trees.
Lincoln Beachey's machine was the product of the pioneering genius of Glenn Curtiss, founder of the aircraft enterprises
that bear his name today. Curtiss with his talent for mechanics and zest for speed moved naturally from racing bicycles
to motorcycles, to flying, dominating each field in turn.
Overshadowed perhaps by the more spectacular performances of his flying machines was Curtiss's development of light
weight, reliable power plants - notably the liquid-cooled Vee arrangement. The engine in Beachey's pusher was the predecessor
of the almost universal OX-5 of the '20's, and today has reached its peak of refinement in the Allison and Rolls Royce
types. This contribution of practical power, enabling others to materialize their theories of design, hastened the development
of the airplane immeasurably.
The problem of starting the pusher engine without interference from the boom members has been solved by hinging
the aft section.
After Curtiss had taught himself to fly, becoming the holder of international Air Pilot Certificate No.1, he realized
the necessity for training others, and established the Curtiss Flying Schools. Most of the early pilots, including Beachey,
and many World War I flyers received their early training under this system.
With its premier position in aviation history the Curtiss "Tripod" Pusher is a most interesting and challenging model
project. The numerous flying wires, struts and open air controls afford the opportunity for much detail.
To support the weight of the Bantam engine successfully the landing gear and center section braces are an integral
structure of piano wire, on which the wings merely rest. A difficulty: common to all pusher models - flipping the prop
for starting - required a radical solution. The entire tail was hinged at the upper surface and clipped into sockets
at the lower wing, permitting the assembly to be swung up and out of the way without disconnecting any controls.
In the absence of a regular fuselage, the wings must be built first to provide a structure from which the remaining
elements of the model may be located. Cut out 52 ribs of 1/16" sheet, and 6 of 3/8" sheet. This can be greatly speeded
up by snipping a wing rib section from thin sheet metal and cutting around the template with a razor blade. Shape the
trailing edges to a wedge section, 1/32" thick at the rear edge. Pin the leading edge, shaped of 3/16" x 3/8" hard balsa,
to the plan at an angle to match the nose of the ribs. Cement the tip and center ribs to the leading edge and pin the
trailing edge against them. Fit shims under the junction of the ribs and trailing edges to maintain the contour of the
wing section. Insert the remaining ribs, and fit the spars of 1/16" x 3/16" hard balsa. Remove the wing from the plan
when dry and re-cement all joints. Sandpaper the framework carefully to remove any bumps that may spoil the finish.
Cover the wings with light weight Silkspan, sticking the paper to the bottom of each rib to preserve the camber of the
Shape the wing struts A, of 1/8" x 3/16" hard balsa to a streamline section at the center and to 1/8" diam. at the
ends. Drill 1/8" holes through the wings and cement the struts in place, beginning at the tips and working toward the
Form the upper portion of the rear motor support B, and the front support D, of 1/16" piano wire. Cut two plates
C, of .020 brass strip. Drill a number of large holes in them to permit the cement to anchor them securely to the wing
surface. Slide the motor supports through the plates and complete the bends. Push the wire supports through the slots
provided at the center of the wings and cement into the upper wing.
Curtiss Pusher 3-View
Attach the motor mounts E, of ,1/4" x 3/8" maple to the supports with clips F, of .020 brass strip. Form the motor
braces G, of .049 piano wire and work them carefully into position through the bottom wing. Enlarge the holes through
the wing if necessary to simplify installation. Clamp the braces to the outside of the motor mounts with clips F. Bend
the front wheel support H, of 1/16" piano wire. Clamp the rear end to the inside of the motor mounts with a brass clip,
and bind to the front motor support with fine wire. Form a pair of rear axle trusses I, of .049 piano wire. Clip the
inner ends into the rear plate C, and bind the outer ends to the motor braces G, with fine wire. Link the trusses I,
to the front wheel support H, with it fork J, of .049 wire, Check the alignment of the wing assembly carefully - bind
all overlapping joints with fine wire, and solder. Solder the clips F, to the struts, and solder the nuts of the 2-56
machine screws to the clips to simplify assembly. Solder the struts to the plates C wherever they pass through. Be sure
all parts are clean and bright. Use acid core solder, a well tinned iron, and the job can be done quickly without danger
of charring the wings. Fair the struts Hand J with strips of 1/8' x 3/16" hard balsa recessed to fit the wire.
Make two bearing plates O, of .020 brass to support the control shaft. Drill 1/8" holes through the 3/8" thick ribs.
Assemble the horn N, of .030 brass and a 1/16" I.D. eyelet, on the shaft in the mounting bracket M. Solder the horn
assembly to the shaft and slip the unit into the wings. Bolt the bracket to the motor bearers and cement the bearing
plates O in position. Slip the upper horn P, and the lower horn Q on. the shaft and solder quickly in place to prevent
charring the wood. With the horn N parallel to the motor bearers, the upper horn P should be pointed toward the boom
hinge point, at an angle of about 60°. The lower horn Q points toward the center, parallel to the wing span.
Fit the engine in place and mark the bolt positions. Remove the bearers and drill. Attach the motor and work the
unit back in place.
Assemble the tail booms directly on the plans of 1/8" dowels, joined by 3/32" x 1/8" hard balsa streamlined struts.
Use several coats of cement at the joints. Lash the hinges L, to the booms with thread and coat with cement. Slip the
booms onto the spur of brace G protruding above the upper wing. Fit bearing K in place and solder to the wires where
they intersect, using a minimum of solder to prevent seizing up the hinge.
Cut the stabilizer of 3/32" soft sheet balsa, sandpaper carefully and cover with Silkspan. Set the stabilizer in
place and align it with the wings while locating the lower ends of the booms. Reinforce the boom with a wedge
of 1/8" balsa. Cut the lower booms apart and cement sockets of 1/8" I.D. aluminum tube in place on the stubs. Push the
booms in place and file the notches in the dowel stock. Raise the tail and bevel off the upper part of the dowel in
front of the notch, to permit it to snap into place. Drop the .016 piano wire clip in the notch and lash to the boom
with thread and coat with. cement.
Hang the elevator on the stabilizer and solder the horn R, to the left hinge. Form a 1/8" I.D. eye in a 12" length
of .049 piano wire and hook it into horn P. Set the elevator in neutral, and with horn N parallel to the motor bearers,
bend the end of the push rod into the elevator horn. Solder a small washer to the end of the' wire to retain it in the
Cut the ailerons of 3/32" soft sheet balsa. On the original model they were hung on the rear struts with hinges S,
of .020 brass. Threads passed over 1/4" diam. eyelets, cemented in the corners of the front struts, connected the ailerons
to the shoulder yoke at the seat. Diamond shaped horns of .020 wire were cemented to the surfaces. The upper line was
rigged from the left aileron to the right, over the upper fairleads. Each lower line was rigged to the corresponding
side of the shoulder yoke, over the lower fairleads. For flight the yoke was locked in place. If desired the ailerons
may be merely cemented to the struts, or omitted entirely for flying.
Mount the control column of 3/32" diam. dowel between the seat supports with a short shaft of .020 wire. Link the
column to the U-control system with a push rod of .049 wire. Cement the control-line guide of .049 wire to the left
outboard struts, just below the ailerons. Attach a pair of .016 lines to horn N, and pass them through the guides.
Install the ignition system using medium size batteries and a midget coil. Solder all connections and lash the batteries
and coil in place with a couple of turns of rubber. Lead the negative side of the battery to the ground and provide
a booster attachment on the positive side of the coil.
A heavy, wide bladed propeller is necessary to absorb the torque in the small diameter required. Carve a left hand
prop of maple, using a spokeshave and cabinet rasp for speedy roughing down.
Build up a dummy radiator of 3/8'" soft balsa and cover the front with fine wire screen. When cemented between the
motor bearers the batteries are considerably camouflaged by it.
Apply several coats of shellac to all bare wood parts. Spray the wings with water to shrink the tissue and apply
two coats of dope, and one of thinned shellac when dry. Finish all wire struts and horns with flat black paint.
When flying, clip booster leads to the ground and coil. Be sure they are not crossed. Release the tail booms from
the sockets and lay the tail over the top-wing. The prop can then be easily flipped over in the conventional manner.
A length of rubber tubing slipped over the intake pipe, projecting between the batteries and radiator, may be pinched
shut to simplify choking and eliminate priming. No trouble was encountered in operating the engine with the propeller
specified. Closing the booms while the engine is running proved even simpler than expected, due to the smooth functioning
of the clips. For the most stable flights the C.G. should be well forward. Add weight to the front wheel support H,
under the seat, if required.
Due to the tricycle landing gear the model may be run easily along the ground, lifted off when desired and brought
down without danger of nosing over while feeling out the controls.
Wherever exhibited the Curtiss Pusher will always provoke discussion of the pioneer days, of the men like Lincoln
Beachey who flew with such skill and daring, and of others like Glenn Curtiss who created the machines through vision
and infinite patience.
Curtiss Pusher Plans
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 November 1, 2014