Elias Aircoupe (oz1195)

About this Plan

Elias Aircoupe. Peanut scale 1930s parasol model.

Quote: "G Elias and Bro Inc Aircoupe, by Walt Mooney. The Peanut Perfesser cooks up another unique little model for the indoor flier who likes building unusual subjects. May not be a contest winner, but it sure is a fun flying Peanut!

This little Peanut Scale model was designed in an attempt to obtain a consistent, one-minute duration Peanut. Under a 25-foot ceiling it has so far proven itself a failure. It has given a top duration of 56 seconds, and has on about ten occasions flown for a duration of 53 seconds. Part of the reason is that it is heavier than necessary.

With the dummy plastic cylinders and the aluminum tube exhaust ring, it turned out slightly nose heavy and had to have a little clay ballast at the tail skid to achieve the center of gravity position indicated on the plans. As a consequence, without the rubber motor, it was flown at a weight of 11.5 grams.

The best motor was a twenty-inch loop of 2.5 millimeter rubber. About 2100 turns can be put in this motor. With a little care in the structure, and (maybe) soda straw cylinders. his model might be able to break a minute, but the one in the photos hasn't been able to do it so far.

The Elias firm built several airplanes, none of which were very successful. The little Aircoupe, however, looks like a good design for model flying. The model in this article was rather simple to build and to trim out for flight. It flies in smooth left circles and is stable enough to recover from disturbances.

The construction of this model follows standard practice in all respects and should present no problems to anyone who has built a few models before. In the interest of keeping the model light in weight, the structure has been kept to smaller size members than the author usually employs. This means that either the model covering must not be shrunk or doped to avoid warps or the components must be held in some sort of a warp proof jig until the dope is completely dry.

Because I have recently received a letter complaining about my use of 1/20th square balsa in the previous Honey Bee article, I feel I have to make a plug for a supplier of these lightweight balsa sizes. They can be purchased through: Peck-Polymers, Box 2498-MB, La Mesa, CA 92041, (619) 442-4636. Peck-Polymers has this size balsa and all kinds of other model building supplies. If you haven't tried them, send $1.50 for their catalog.

Balsa strips were laminated to form all the surface outlines and the wing tips. When laminating with basswood, it is possible to bend the sticks around a lineup of pins delineating the inside of the surface outline. This is almost impossible with balsa laminations, so, using 3/32 balsa sheet, cut out patterns for the vertical tail, horizontal tail, and the wing tips. Sand the outline smooth and then using a crayon or a candle, rub enough wax on the edges to prevent the laminations from sticking to the patterns as the adhesive dries. Use white glue for the adhesive. Thin it out with an equal amount of water.

Get a roll of masking tape and tear off about 15 or 20 strips a quarter of an inch wide. Stick these somewhere you can easily get at them, like on the edge of your workbench. Now take three of the strips you are going to use for the horizontal tail outline. Coat one side of two strips with the adhesive and stick all three together. Wet the outer one with water. Lay one end of this three-layered stick into the notch in the pattern, and lock it in place with a length of tape wrapped around it and pressed on each side of the pattern. Now, with light tension on the stick, pull it around the pattern making sure that it is against the pattern wherever the stick is being bent. Use tape pieces as necessary to keep the stick in place. When you have progressed all the way around the pattern, cut off the excess stick so the other end can also end up in the notch.

Check the laminations to see that they are properly aligned and the way you want them before they have a chance to dry. They can be adjusted for a few minutes! Make the vertical tail outline and the wing tips in a similar fashion.

The rest of the model construction follows standard construction methods, so go ahead and build your Elias Air-coupe, then see if it will fly for more than a minute indoors. Its fun to fly even if the flight is a lot shorter than that."

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