Megowcoupe (oz2070)

About this Plan

Megowcoupe. Radio control scale model. Wingspan 46 in, for .049 to .099 engines.

Flyline kit, based on an old Megows design.

Quote: "A new concept in R/C for confined flying areas. Big, slow and beautiful! Megow's 1935 Monocoupe D-145 rubber kit, size doubled, is the answer. For 2 ch RC and .049 - .061 power."

Update 09/06/2021: Added electric conversion article from Flying Models, July 1983, thanks to RFJ.

Quote: "Electrifying the Flyline Megowcoupe. Putting a charge in an old favorite. By Don Srull.

The .05 electric motor is becoming the most popular and practical size for sport R/C models. Both Astro Flight and Leisure Electronics have several fine .05 motors in their lines of electric powerplants. The most widely used battery for these motors seems to be the six cell, 1.2 ampere hour (so-called sub-C cell) pack. Luckily, there are also many fine kits avail-able which are well-suited to .05 electric motors, and they offer an easy way for a newcomer to give electric a try. Two such models which I have successfully converted to electric are the all-foam, ready-to-fly Goldberg Ranger 42, and the Flyline Megowcoupe. We will briefly describe how our .049 powered Megowcoupe was converted to .05 electric.

The Megowcoupe is a 46 inch span, semi-scale model of the Monocoupe. It is a typical built-up stick-and-tissue design, and with 290 square inches of area it turns out to be a very light, slow flying model with an .049 glow engine. Ours weighed about 15 ounces with a Cox Golden Bee and small two channel radio for a very light seven ounces per square foot wing loading. It could be flown virtually anywhere. With the .05 electric and three channel radio it weighs about 30 ounces, so it flys and glides a little faster. It still is groovy and stable, and has a terrifically good glide. The only real limitation now is that we don't fly from high grass fields since the heavier weight and higher landing speeds would tend to damage the landing gear too easily.

To modify the Megowcoupe for electric we need to do three things - attach the motor, build a battery compartment, and add a third servo for motor on/off control.

The easiest way to mount your .05 electric motor, is to attach it to the existing firewall with thin sheet aluminum straps. First cut a hole in the center of the firewall into which the motor can slide. Make two aluminum straps which will hold the motor to the firewall such that the prop is 2-1/4 inches beyond the firewall; this will provide proper clearance between the cowling and propeller. The aluminum straps are attached to the front of the motor case with two machine screws, and to the firewall with sheet metal screws as shown in Figure 1. Make sure you wind up with no side thrust and 1° or 2° downthrust.

The six cell battery pack is heavy (about 11 ounces), and must be properly secured within the fuselage. The 1/8 inch sheet balsa floor and 1/16 inch sides of the cabin area provided an ideal spot. One quarter inch square balsa and 1/16 inch plywood are used to construct the battery compartment and access hatch as shown in Figure 2. The access hatch on the fuselage bottom provides an easy means of removing or changing the motor batteries. The batteries can be slid into place and secured with a single rubberband.

A third servo to control an on/off micro switch will be necessary. The tiny micro switch can be attached to the servo with double-sided foam tape, or simply glued to it. The proper wiring of the motor, batteries, charging jack, and switches will be described in instructions provided by the manufacturer of your motor. However, a good and clear schematic was shown in Bill Winter's column in the March, 1983 issue of Model Aviation. I recommend you read it. Speaking of good info on electrics, I recommend you join the newly formed Society of Electric Aircraft Modelers (SEAM) to keep up to date on everything electric. To join, send ten bucks to SEAM, 11632 Flamingo Drive, Garden Grove, California 92644. You will also get the great SEAM newsletter, which is loaded with hints, tips, and practical info.

Back to the batteries; notice the small cooling hole in the fuselage bottom. It allows air to flow over the batteries and out the fuselage. Also, make sure that the hole for the motor in the firewall is a little larger than the motor diameter; this will allow cooling air to flow around the motor case. By the way, I found that a 7/4 wood prop was best for my model; but you should experiment with 6/4's to 8/4's.

Before you try a test flight, make sure the CG is still within the limits shown on the plans. If not, shift the radio batteries and/or add ballast. Next, trickle charge the motor batteries at about 100 mA for at least 12-14 hours the day before you fly. This will bring all the cells up to an equal, full charge. Use this charge for your first flight of the day, then use your rapid charger for subsequent flights, using the manufacturer's instructions. Make sure your radio works properly with the motor off and on.

If you have a smooth surface handy, let the Megowcoupe take off for its first flight. If not, ask a trusted friend to give you a running launch while you man the transmitter. Keep the climb-out shallow and straight until you are up 50 feet or so. Then feel the controls out with motor on and off; talk about low idle RPM! Remember, the Megowcoupe will want to fly and glide a little bit faster than the glow engine version and tip stalls can be a little easier to get into.

After a few quiet and pleasant electric flights it's easy to forget how it was before with the oil, the noise, and the hassle of flipping that little prop endlessly; and you sure couldn't re-start an .049 in flight for a go-around, could you?"

Update 29/8/2026: Added kit instructions, thanks to SteveJohnson.

Quote: "MEGOWCOUPE Building Hints.

You have purchased a new dimension in R/C known as 'Giant Schoolyard'. Flyline peers into the future and sees this type of Big, Slow and Beautiful airplanes as the most enjoyable and inexpensive form of flying available. If you have built small rubber band powered models before, no problem will be encountered in construction. But if you have not we will attempt to pass on building hints that will be'of value for you to produce a beautiful Megowcoupe for your enjoyment!

FUSELAGE: Cover plan with wax paper. Pin down the 1/8 square longerons inside the black triangles which denote the fuselage side. Note that the cabin area is 1/8 x 1/4 balsa, instead of 1/8 square. Add the 1/8 square upright and also the 1/16 x 1/8 braces from rear of cabin aft, plus #F8. Remove pins and lightly sand structure with a flat sanding block. This finishes one side, however, we need two. Lay another piece of wax paper over the just finished side and repeat the above. This will assure two identical sides. For maximum speed in building, use any of the cyanoacrylate adhesives now on the market, but be sure to read the warnings on the bottle label!

Remove sides from plan and sand lightly on each side, again with flat sanding block. Cut out #F9, which top of same glues to each side at the bottom of window line. It should be 1/8 in short on bottom, as the spruce langing gear mount fits here. We are how at the critical part of the fuselage/sides assembly, as this must insure a 'true' plane. On flat surface, stand sides upright with #F9 in position. Use any heavy object, bottles, cans (Clorox, Juice, etc.) which will hold a true 90° vertical position against each side. Insert a weight (file, pen etc.) at extreme tail end of fuselage sides, enough to keep flat against surface. Now position #F9 exactly, making sure sides are congruent, and glue #F9 in place. Follow by glueing in all 1/8 square cross members..."

Update 10/9/2026: Replaced this plan with a much clearer copy, scanned from fullsize at 600 dpi, thanks to SteveJohnson.

Supplementary file notes

Electric conversion article.
Instructions.
Previous scan version.

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