This model works on the same principle as the real Hafner Rotabuggy from WWII, being tethered and pulled through the air to spin the blades and create an air-catching disk which then lifts the craft into the air. Craft like the Rotabuggy, Focke Achgelis Fa330 and many others would have been towed by a truck or a U-Boat to give it speed and lift, but the model I will teach you how to build will work like a traditional kite powered by the wind.
To build this model you will need;
String (use any string that you would associate with kite flying. I recommend thin nylon string.)
Wire and Pliers
Prestik/Blue Tac/Putty/Small coin} to use as ballast
Something to wind the string around
A windy place to fly it in
Packing/Floor insulation/other lightweight foam sheets (I used the kind used for protecting eggs when you buy a tray of 30.)
Step 1: Making the Rotors
First, cut a blade out of the foam sheet. Then trace it and make 2 others like it. To make the centre that holds them together, cut out an equilateral triangle with each side the same length as the width of a blade. Tape the blades to it as shown. Then poke a hole in the centre for the rotor shaft to fit through.
Cut 2 small circles out of the foam. These will help reduce friction. Make a small hole in the centre of each one. Then place all the parts mentioned (and 2 beads) onto the pin to create the rotor hub. The order should be like this: 0-o-O-X-O-o----------------
If 0=pin head, o=bead, -=pin shaft, X=rotor centre.
Also cut out a shape like the one shown in the 2nd last picture. This is what the shaft will be connected to the fuselage with.