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Website
visitor Ernie S. wrote to say that the Miss Paranoia that he
built back in the 1970s has been converted to electric power, and
that he would like to see the construction article and, in particular,
the plans in order to see where the center of gravity is supposed
to be. Scale quarter midget racers with their thin wings and short-coupled
fuselages can be sensitive to CG; getting it right can make the
difference between just one short flight and many years of enjoyment.
The AMA Plans Service no longer sells plans for the Miss Paranoia,
probably because it uses a fiberglass fuselage and foam wings, so
there's not much chance anyone will be building one from scratch.
Miss Paranoia
by John Fotiu
An important part of racing is competitive "psych." Miss
Paranoia can unnerve the most ruthless competitor, leaving
a trail of fear wherever she races. |
The Miss Paranoia is a highly competitive quarter midget designed
for winning contests. To win, the airplane must be fast enough to
stay ahead of the pack. Equally important, it must have good slow-speed
characteristics for the idle landing requirement. if the airplane
stalls or is unstable at slow speed, you may not be able to race
the remaining heats because of landing damage.Tight turning
is also important in cutting off precious seconds. Consequently,
the wing is probably the single most important factor in designing
a racer. After trying several airfoils in the past two years, I
settled on a modified Stafford design, as refined by Bob Jones of
the Mentor area. His basic modification to the Stafford design was
to streamline the tip airfoil for less drag. This wing design has
a good top end, turns tight and slows to walk-on landings.
Miss Paranoia was fifth in the Pylon Racer category at Toledo.
At the Mentor World Q/M Championships, the design placed
second, third, fourth and fifth.
Buy a fuselage ($20.00), or a full kit ($32.00) from the
author.
The new Taipan 15, with a homemade exhaust pipe. Note the
cutout in the fuselage to clear the pipe.
Use a stick to spread epoxy inside the rear portion of the
air scoop. The horizontal line in the fuse, at the end of
the tape, is a soda straw, which is epoxied inside the fuse
as a stiffener.
Tape a steel rule to the fuselage, then scrape a slot for
the stab with a sharp X-acto.
The sheeted wing core with the landing gear trunnion cut
out, landing gear block and wire gear.
The author prefers an open engine installation for better
cooling and easier maintenance. RPMs courtesy SuperTigre.
A close-up photograph of the tail shows the partial rudder
and the recessed tail wheel. |
Website visitor Ernie S. was kind enough to send this photo
of his Miss Paranoia that he built in the 1970s and has
converted to electric power. |
The fuselage and tail assembly are basically just along for the
ride, and should be as streamlined as possible. The Miss Paranoia
has probably the least frontal area of any quarter midget yet. This
is due to the lack of cowl cheeks, and utilization of the streamlined
belly scoop to obtain the five-inch height requirement.
Construction Construction is relatively
simple and should present no problems. Fuselage: The fiberglass
fuselage is hand laid, using 6 oz. cloth and epoxy resin. The use
of double layering in areas of high stress and a soda straw ribbing
make the fuselage quite strong for its 6 1/2 oz. weight. To purchase
a fuselage and belly scoop send a $20.00 money order to: <deleted>.
Keep in mind that when gluing anything to the fuselage,
such as the scoop, firewall, etc., epoxy must be used. Polyster
resin will not stick to the fuselage. Engine Installation:
The Miss Paranoia front end was originally designed around the O.S.
15 engine. Since the ST, K&B and Taipan engines use a larger
mount than the O.S., considerable grinding of the mount will be
necessary to fit it into the narrow nose. The engine may
be mounted sideways, upright or inverted, but keep in mind that
the tank center line must be even with the center line of the needle
valve. Begin the firewall installation by rough-cutting an opening
for the engine. Drop in the engine mount, and bolt the engine to
the mount. Now make a 1/32" plywood spacer to fit between the fuselage
front and the spinner back plate. Bolt the spinner assembly in place,
and tape the spinner solidly to the fuselage. Again, this may take
a few trial fits because of the grinding necessary to the larger
engine mounts. Cut out the firewall and drop it into position
through the wing saddle opening. Trim the edges of the firewall,
until it fits flush against the back of the engine mount. Coat the
front of the firewall with a light film of epoxy before gluing it
in place. When dry, remove the engine. The engine mount
should be lightly epoxied to the firewall. The engine mount holes
are now easily drilled in the firewall, after which the 6-32 blind
nuts are installed. The firewall may now be permanently bonded in
place, using small pieces of epoxy-saturated fiberglass cloth.
When the engine and spinner are properly installed, there
should be a 1/32" space between the fuselage and the spinner.
Wing: Begin by cutting the root and tip templates from 1/16"
plywood. Be sure to cut the cores with the 3/16" washout, as shown
on the plans. Make up four wing skins from 1/16" balsa sheeting.
The entire wing can be covered with four 1/16 x 4 x 36" sheets,
if you lay them out as shown. Using Sig Core Bond or other contact
cement, carefully cover the wing halves in the polystyrene blocks
they were cut from. This will insure that the washout will be the
same in each wing panel. Trim the protruding balsa and glue
on the leading and trailing edge strips, using Titebond or equivalent.
Block sand the 3/8 x 5/16" trailing edge strip to conform with the
wing airfoil. This should make it easier to center the 1 x 1/4"
trailing edge stock on the wing. If you choose to use the
one aileron setup, tack-glue only the right aileron stock in place.
Glue on the wing tip blocks, and sand each wing panel to airfoil
shape. The landing gear blocks are made by laminating 1/8"
plywood. Locate their position on the underside of the wing by measuring
from the plans. Lay the landing gear blocks on the sheeted wing
and trace with a ball-point pen. Remove wing skin and polystyrene
foam to a total depth of 1/4". Epoxy the landing gear blocks in
place flush with the bottom of the wing. Block sand each
wing root to obtain the correct dihedral, and epoxy wing halves
together. Add a strip of two inch wide fiberglass tape or Celastic
to center section. Position the 1/8 x 1 x 1 1/2" plywood
landing gear support on top of the wing center section. Drill 1/8"
diameter holes for the landing gear wire. These should go completely
through the wing. The landing gear wire should protrude at least
1/16" above the plywood support. This type of landing gear has proven
itself to be very strong and lightweight. Remove the trailing
edge stock and install the aileron torque rod assembly. Also drill
the 3/16" diameter holes in the leading edge of the wing for the
locating dowels, but do not epoxy in place at this time.
Using the template on the plans, make the 1/8" plywood dowel
locator and epoxy in place on the fuselage. Epoxy a block of the
motor mount stock to the rear inside lip of the fuselage wing saddle.
Also, add the wing saddle tape.
At this point, the wing locating dowels are epoxied in place and,
while the epoxy is still tacky, the wing assembly is positioned
on the fuselage. When completely cured, the rear wing hold-down
hole is drilled and tapped for the 10-32 nylon bolt. Bolt the wing
in place, and epoxy the front portion of the belly scoop to the
wing. The open ends of the scoop are capped with 3/32" medium balsa.
Also, cut an access hole in the scoop for the nylon bolt.
Tail: All tail surfaces are cut from 3/16" medium soft balsa.
Slot the rear of the fuselage, using a Zona Saw, Dremel tool, or
by repeatedly scraping with a sharp X-acto knife. Finish:
I used two coats of Super Poxy primer, followed by two thin coats
of Super Poxy color. The wing is covered with Super MonoKote, with
the exception of the center section, which is also Super Poxy because
of the scoop. The numbers on the rear of the fuselage are
Para-Tipe press-on letters, with clear acrylic sprayed over them
for fuel-proofing. You must first lightly sand the Super Poxy finish
to get the press-on letters to stick. Final trim is black and gold
J.D.'s Multi-stripe. Radio Installation: I mounted my servos
toward the front of the fuselage to aid in balancing. The servos
are mounted on a removable plywood tray, in order to gain access
to the battery pack and tank. It is advised not to cut out
the canopy area of the fuselage. This will allow more room for the
receiver. The rudder servo, which is mounted in the fuselage,
also mechanically drives the aileron torque rod, as shown in the
photo and plans. The Kwik-Link is simply disconnected when removing
the wing. Be sure to use a 2-56 lock nut with the aileron Kwik-Link,
so it does not lose trim when disconnected. With the radio installation
shown, the airplane will balance out correctly.
Flying Balance the model on the CG, and set up
control surface throws as follows: elevator - 1/4" each way; aileron
- 1/4" each way; rudder - 3/8" each way.
If you can fly a low-wing sport or pattern airplane, you should
have no problems flying the Miss Paranoia. However, due to its clean
design, you have to induce enough drag to slow the airplane down
for a safe landing. This is done by holding in about one-fourth
of the elevator throw, at a near idle throttle setting, well in
advance of the final leg of the landing pattern. Practice slowing
the plane down at high altitude to get the feel of it. There
are about 15 active contest fliers racing the Miss Paranoia. I sincerely
hope you decide to make it 16. Gentlemen, start your engines
and get ready for another one of those two-minute paranoid acts!
The radio installation is pushed to the front
of the fuselage. Note that the rudder linkage goes through
a reduction arm to cut down on throw.
Miss Paranoia Plans
Notice:
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.
Try my Scale Calculator for
Model Airplane Plans.
Posted July 30, 2013
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