Buzz Bat (oz5584)

About this Plan

Buzz Bat. Flying wing design, for the Buzz CO2 engine.

Quote: "Buzz Bat, by Frank Ehling. THE CO2 motor has given the modeler a chance to display his talent for design, because the model can be built quickly, and if there are any changes they can be made easily. The engine can be run at any speed to get the ship to do just what the builder wants. The engine can be made to run in either direction, which is handy when you want to make a pusher or tractor; none of the work of carving the prop is lost since it can be slipped on the shaft either way.

Now all we need are a few brave modelers to give us something a little different from that pylon design (the pylon is the best under the AMA duration rules). It may be a good idea if clubs would add a design event to their contests, with some nice prizes - that's the best way to get modelers working.

When the Buzz CO2 engine was announced we wanted to try it right out, and the flying wing looked best to us for the purpose. A flying wing is simple; dihedral in the wing is used for lateral stability; sweepback with upturned wing trailing edges gives longitudinal stability. The rudders are placed at the wingtips as this is the point farthest behind the CG.

WING: As there isn't any fuselage to slow us up we'll start right in on the wing and cut out the ribs along with the spars and trailing edges. Lay out the spars over the plan and cement ribs in place. (Use wax paper over the plans, of course.) The leading edge can now be cemented in place. Cut out the wingtips - from bending stock, because they will have to be warped later to make the wing glide properly. Sand the wing frame smooth - this is important because only with a smooth frame can you do the best covering job. If the framework is rough the covering job will look as if it was done in the dark. When you are sure the wing is smooth, go over any weak joints with cement because if the wing is weak it will warp out of shape when covered.

Cover the wing in sections: 3 on top and 3 on the bottom. Spray with water; when dry, coat with dope diluted 50% with thinner. Dope is rough on light structures so add a few drops of castor oil to your thinned mixture to keep the dope from pulling the wing out of shape.

The rudders can now be cut out, sanded smooth and cemented in place. Be sure they are cemented on straight as it takes only a little rudder to force your model into a turn.

The tube that holds the tank and motor is bent around a dowel. Cement a plywood bulkhead to the end, cement the seam well, and attach the motor. Fasten the tube in place on the wing and, when dry, slip in the tank and glide the ship. When the glide is flat (obtained by sliding the tank back to check a dive, and forward to kill a stall*), cement a balsa block to the front end of the tube and streamline to shape shown on the plan.

The prop is carved from a block of bass or pine. Carve thin blades, but be sure to dope well as too light a prop is hard to get running in the direction you want. There isn't much to say about flying the wing as adjusting is very easy. Bend up the wingtips to get the ship to climb, and if one is bent more than the other it will tend to turn the model. When you have finished your model and learned what makes it tick, you will want to try one of your own design - they are a lot of fun!

*Note that the tube from the motor runs to the for-ward end of the tank. Don't reverse the tank - if you do, liquid CO2 will run through the motor as soon as the model starts to climb and the motor will immediately slow down and probably stop running. If the tubing is run as specified, liquid CO2 will not reach the feed pipe when the model climbs, and if the nose should point down the motor will stop - a good safety feature!"

Direct submission to Outerzone.

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