Change one Westbury’s single cylinder 2-stroke engine, the Atom Minor Mk 3, the final evolution model, this one was released in 1947 to conform with 6.0cc competition limits. The original model with its rotary induction valve could swing a Ø30 centimeters x 15 centimeters pitch propeller at 6,500 rpm in standard trim. This would have provided 40.2kph performance in a 61 centimeters hydroplane or 88.5kph from a 43 centimeters, the design however was conceived primarily for model aircraft applications where it can be mounted upright.
The original design have been modified in this project in order to can be mounted inverted, following some specifications from Westbury’s book and increase its capacity from 6.0cc to 6.5cc without increase the original model’s weight and chassis could swing a Ø30 centimeters x 15 centimeters propeller at 7,000 rpm providing 45kph performance in a 61 centimeters scale model aircraft or 100kph from a 43 centimeters model.
Modelign and rendering using SolidWorks.