Mini Mono Article & Plans
August 1970 American Aircraft Modeler Article

August 1970 American Aircraft Modeler Table of Contents These pages from vintage modeling magazines like Flying Aces, Air Trails, American Modeler, American Aircraft Modeler, Young Men, Flying Models, Model Airplane News, R/C Modeler, captured the era. All copyrights acknowledged.

Its profile on the plans looks like Mini Mono designer Ralph Pearson fashioned it after the F-86 Sabre, but that's mainly because the Pee Wee .020 engine is not shown. This 1970 vintage 2-channel R/C model was a marvel in compactness for its day. An Ace superhet pulse radio did the guidance for an all-up flying weight of only 9.5 ounces for a 21" wingspan low wing airplane. Supposedly it would bore holes in the sky with impressive aerobatics (for 1970). Full-size plans were printed on four pages along with the construction article.

Mini Mono

Lively small-field flyer uses .020 and pulse aileron/elevator. Stunts like crazy, an expert's delight. Suggestion - take Mini Mono on a trip; it fits in most large suit cases. Although small, this plane is not fast. Pee Wee engine has restrictor to reduce power. A schoolyard flyer. Who likes single channel? Two groups: low-budget beginners and experts who think it is more sheer fun than getting Excedrin headaches over powerful, fast, multi-bombs or 707's.

It was while devising a plate for push-rod operation of rudder and elevator that I decided, for good measure, to use this plate for ailerons with elevator trim. The resulting model became the Mini Mono.

Its performance was gratifying. Initial flights were surprisingly smooth with beautiful aileron turns. As a bonus (to me, at any rate), this plane is not as fast as it looks. However, a Vogt restrictor is used on the Pee Wee 020. Even with the engine set wide open, some of the exhaust area is still covered, and the loss of rpm is quite evident. By all means, use a restrictor on the first flights.

I use 3.6 volts (3-225's) on actuator, tapping the battery pack at 2.4 volts for Ace Commander DE Superhet. With 3.6 volts to actuator, six to eight flights per charge is the limit, but that is usually sufficient.

With a transmitter not equipped for rate, the elevator trim feature must be eliminated. In this case, 2.4 volts can be used for receiver and actuator. This makes for simpler installation and a lighter model. In any case the transmitter must have a width ratio of more than 80-20.

Do not try rudder only on this particular model. For ailerons only, keep tail surfaces extra light, put aluminum straps on the elevator hinge-line, and move the actuator forward slightly for balance. Either way, the overall weight should be kept to 10 oz. or less. The original model came out at 9.5 oz.

Because the Mini Mono plans are presented full-size, the building instructions are brief, touching only on special construction details. To build the model, cut out the plan pages and make Xerox copies of each. Scotch-tape them together in the proper relationship and use them as working plans.

Mark bulkhead locations on fuselage sides and assemble upside down over the centerline. If doublers are left off until the sides are pulled together at nose and tail, less distortion results. When dry, add doublers, 1/8" sq. strips, and firewall braces. Also add wing-retaining tongue at trailing edge. Leave top and bottom covering for later when all equipment, location, and operation have been checked out.

The aileron-elevator plate can now be made, using dimensions taken from the views on the plan. Assemble the parts with epoxy and thread over a piece of wire the same size as the actuator shaft. A little wax on the wire will aid removal of the assembly after the epoxy has hardened.

Check wing fit and if satisfactory glue leading edge dowels in place. When this is dry, drill hole for retaining screw.

Cut out ailerons and tail group; hinge as desired. Surfaces must be able to flop of their own weight. Aileron horns are made from 1/32" wire, nylon or brass tubing, and a drilled nylon fitting.

Mount actuator in the wing, connect linkage (z bend is for adjusting length) and check for smooth operation. Use inner holes on plate and restrict actuator movement to 45 degrees each side of neutral. Ailerons should move approximately 15 degrees each side of neutral.

Make a pushrod from medium 1/8" sq. and 1/32" wire. 'The rod is held in place at the elevator horn with a slice of small fuel-line tubing used as a retainer. It also acts as a sort of centering device. Mount the wing on the fuselage and connect elevator pushrod. Check operation of the elevator for 1/4" total movement - more up than down.

Remove wing, radio, etc. Drill holes for the engine to one side of the firewall so that 3 degrees of right thrust will center prop. Now finish fuselage top and bottom.

Shape a canopy from soft balsa and place it so that the back half can be removed rearward for removal. Fuselage under the back half is cut out slightly smaller than the canopy. Reach into this opening with tweezers to attach the pushrod to the plate.

Note that the switch is removable but is held in place by the wing. Use a small brace to strengthen the notch-weakened area. The battery is wrapped in foam and wedged into the nose area.

Hobbypoxy clear was used on all sheet surfaces. Three coats give a light fuel-proof finish with no warpage. A bit of colored trim livens up the model. The original wing was covered with Japanese tissue, but I intend to recover it with MonoKote. Weed-ripped tissue is too often a problem.

Check for 5 degrees down- and 3 degrees right thrust for the first flights. Do test flying over a grassy field on a calm day. Use a restrictor on the engine and conduct powered glides, increasing power and making adjustments to thrust line and elevator if necessary. Keep the model in close. These small models can't carry much antenna (a vertical antenna is recommended), and orientation is difficult if they are too far away.

Mini-Mono Plans (Plate 1)

Mini-Mono Plans (Plate 2)

Mini-Mono Plans (Plate 3)

Mini-Mono Plans (Plate 4)

Posted June 29, 2013