Website visitor Marlene B. wrote to ask
for me to scan the articles for the Pogo Formula I race and the Hot Canary Formula II racer,
both having appeared in the August 1971 American Aircraft Modeler. They were presented as
a matched pair even though each was created by a separate designer, Bob Morse for the Pogo,
and Bob Seiglekoff for the Hot Canary.
A pair of unique and well-designed racers for Formula I (Pogo) and Formula II/FAI NMPRA (Hot Canary) racing. These are just as
competitive as the usual planes.
By Bob Morse
THE OWL RACER, designed by George Owl and built by John Alford, was featured in the April
1971 AAM. This time we present a Formula I racing version of this most unusual aircraft. Its
name is Pogo.
Pogo is unusual
because of not using cheek cowls. Wing taper is compromise between area and aspect ratio requirements.
Stabilizer is below wing turbulence.
Not having cheek
cowls, engine is lost in fuselage. Exhaust extension is essential.
The nose cowl treatment makes the difference. The designer departed from the usual cheek
cowls and employed a full-bodied wrap-around cowling which actually will contribute thrust
in flight. The miniature racing version retains the full-bodied engine cowling shape of the
original and the only deviations from scale are those required to meet the NMPRA Formula I
The ship is very stable in flight, showing no tendency to mush or stall in high-speed pylon
turns. It gets up on the step and grooves. If a good engine is up front, it won't be second
The fuselage is built on an inverted crutch, the lower half built up completely on the
1/4 x 1/2" crutch members, including the nose planking. When this has set up, remove the entire
fuselage bottom half, and then add the top formers and planking. Begin construction with the
ply frames, which are cut in separate bottom and top frames.
Cut the fuselage side panels and 1/32" ply doublers to the phantom outline shown. Cutting
them to the finished fuselage shape will result in too shallow a fuselage. Assemble the sides
by contact cementing the doublers to the balsa side panels, being sure to make a right hand
and left hand. Next, glue the longitudinal and vertical stiffeners in place. Cut in the cooling
exit hole in the right hand side plate and add the 1/32" ply air duct before fuselage assembly.
With all the frames cut to shape and the side assemblies completed, begin the fuselage
assembly by pinning the 1/4 x 1/2" crutch members in place on the plan. Glue all frames in
position and, after the glue has set, cement the sides in place, leaving about 1/32" of the
crutch exposed. Next, add the 1/8 x 3/8" soft balsa planking in the nose area. Then add the
landing gear blocks and the 1/16" cross grain bottom sheeting back to the rudder post. This
should complete the entire lower half of the fuselage. Let this set for at least a day before
picking if up.
Next, add all top formers and proceed with the top planking. We planked ours back to the
rear cockpit frame and used 3/32" sheet for this. Add the cowling nose blocks, rough the spinner
area down to size and then mount the engine and spinner in place to assist in positioning
the 1/16" ply spinner plate on the nose blocks. When this is done, remove the engine and shape
the nose blocks into the spinner plate. We used the small drum sander on our Dremel tool,
which did this job quickly.
By now, the fuselage is just about completed so, after a good smooth sanding job, paint
on the first coat of sealer.
The flat bottom airfoil doesn't have a pat technical explanation, but we have had a lot
of experience with it. Jim Kirkland's Shoestring of 1965 was the first Formula I ship to use
it. Joe Foster used it on his Rivets, National Champion in 1967 and 1968. We were hooked on
the wing section after flying two of Joe's Rivets and decided to continue with it on our Ole
Tiger. We've built up a lot of flying time with this section and can recommend it without
reservation, both in high and low speed characteristics. Full elevator turns can be made at
high speed with no tendency to stall or mush and lateral control is excellent in a fully flared
Another welcome characteristic is ease of building. The first step is to pre-glue and sand
the 1/16" medium balsa skins. We recommend taping the 4" sheets together, then reversing the
taped assembly. Open each joint and lay a bead of coating resin in place. Spread the skin
out flat and wipe the excess from each joint. The taped side will be the finished side and
will require very little sanding to finish.
Cut all ribs and put together the right and left hand aileron bellcrank assemblies.
Pin the lower skins to two building boards butted together at the wing center line. With
the center and two tip ribs in place, jack up the end of one board until a straight edge just
touches the top of each of the ribs. This will provide all the dihedral in the bottom surface
and the top surface will be flat from tip to tip. Remove the ribs and begin final assembly
by gluing the lower 1/16 x 1/4" spruce spars in place, adding the half-span 1/16 x 1/4" spruce
doublers. (Do not break the spars at the center line; let them run straight through, tip to
tip.) Add all the ribs and then the top spar with its half-span doubler. Install the aileron
bell cranks with their pushrods in place. Addition of the rear spar, top skins, leading edge
and the sheet trailing edge will complete the basic wing structure.
Wing construction to this point takes four hours, and it is basically finished. (Another
strong point for this airfoil.) All that remains is shaping the trailing edge, adding the
tips and sanding everything to shape. Add the fiberglass cloth strip all around at the center
section joint and the wing is ready for final finish,
The tail surfaces are rather straightforward and need no description. At the leading edges,
we added 1/16 x 1/4" spruce strips which seem to stop the nicks and gouges caused by gravel
thrown back by propwash.
Now to paint the Owl. We have used the coating resin system for a long time now and recommend
trying it. We use Starcast or Francis Products Surfacing and Coating resins.
Begin by applying a brushed coat over the entire ship. After this has set up, go over it
lightly with coarse sandpaper to take the humps out. Brush on a second coat, flowing it carefully,
avoiding runs. If this coat is added with care, the ship is ready for an attractive color
coat. However, for one of those fantastic elbow-power super finishes, sand this coat well
with 320 wet or dry paper, then spray on a coat of DuPont gray lacquer primer. Then sand the
primer coat completely off the ship.
With very little effort, the surfaces are, or should be, glass smooth and ready for the
Hobbypoxy colors. We masked and sprayed the basic red trim with Hobbypoxy Bright Red. For
the pin striping, we used a vinyl tape which seems to stick with a vengeance. Forty feet of
3/32" wide taped (marked 1/16" wide) was 57 cents at the local discount department store.
The material is called Trim-Brite pin striping tape and should be in auto supply stores. Contact
Spartan Plastics, P.O. Box 67, Holt, Mich. 48842, for a local dealer. It's worth trying.
<click for larger version>
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 February 8, 2011