In 1945 William Thomas, President of the Roteron Corporation, began work on a midget helicopter of an original design. By placing its 5-cylinder engine between the two co-axial rotors, he had more space available in the fuselage, and considerable saving in construction also resulted because power was directly transmitted to the rotors.
The rotors each had two sets of blades, a longer set below a shorter set which, produced an anti-torque effect. Both sets of blades were made of solid laminated maple wood. The pitch and speed of either rotor could be controlled and in case of engine failure they could turn by auto-rotation.
The fuselage consisted of a steel tubing frame covered with an aluminium skin and plastic covering. The rudder, supported at the end of two tubes, could pivot from the vertical to the semi-horizontal position. The tricycle undercarriage had three fully swivelling wheels.
Rotor span: 4.72m