Unicopter (oz15394)

About this Plan

Unicopter. Simple rubber powered helicopter model.

Quote: "One blade rotor easily flies this rubber band-powered and paper helicopter. Unicopter, by Bill Hannan.

Helicopters are among the oldest of flying machines - at least in idea form. Leonardo da Vinci was doodling designs for them back in the 15th century. Yet, even today, helicopters remain much misunderstood, and only very recently have successful radio-control models of them been developed.

Our miniature 'copter was designed to provide maximum fun for a minimum investment in time and materials, but will still offer the chance to explore the problems associated with rotating-wing aircraft.

Construction: Begin construction by building the triangular fuselage framework from fairly hard 1/16 square balsa strips. A sheet of waxed paper will keep the sticks from adhering to the plan while the glue is drying.

The fuselage covering may be cut directly from the magazine, or if you like to preserve your AAMs, make a tracing of it on thin paper. Glue the triangular frame to the back of the fuselage covering, and apply a few weights to hold the assembly flat while it dries.

Next, cut the motor stick to length from a strip of 1/4 x 1/8 balsa of medium weight. Cut the angle on the top end, and glue on the little bearing spacer piece, which may be cut to size from leftover motor stick stock.

Bend the lower motor hook to shape from 1/32 dia music wire and bind in place with sewing thread and glue. The rotor shaft bearing is cut from a length of 1/16 OD aluminum tubing by rolling a single-edge razor blade over it. Snap the tubing along the scored line, and sandpaper or file off any rough edges. The bearing is secured to the motor stick with thread and glue.

The completed motor stick may next be glued to the fuselage framework in the position shown on the plans.

The rotor is cut to size from a piece of medium-hard 3/32 sheet balsa. Sand it to an airfoil shape with a sanding block. A general cross-section is shown on the drawing, but the exact shape does not seem to be critical. The rotor hub is made from a hard piece of 3/32 sheet, Carefully cut away one corner to accept the rotor blade. Drill a hole in the hub center for the rotor shaft, being careful that it is 'square' with the face of the hub, so that it will run true.

A length of 1/32 dia music wire is used for the rotor shaft. First, bend the hook end to shape. Next, slide the shaft through the rotor shaft bearing, add a couple of brass thrust washers, and the rotor hub, Using the drawing as a guide, make the right-angle bend in the shaft above the rotor hub, and also at the extreme end of the wire. This small bend serves to help retain the rotor..."

Direct submission to Outerzone.

Supplementary file notes

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