Winner of numerous competitions, Don Boughton has been Australian National Champion and Victorian State Champion for three years in succession.
But during his long and distinguished aeromodelling career it seems not many photographs have been taken of Don Boughton. Certainly not many have survived. To illustrate Don's love of the theoretical aspects of designing his own aircraft and gadgets we bring you a few pages from his sketchbook.
1. A patternmaker by trade, Don was well equipped to make patterns for his range of fireglass propellers, metal engine mounting pans, and fibreglass fuselages. Seen at the bottom of this picture is the pattern for his class 2 teamracer fuselage.
2. This page from Don's sketchbook shows the blade shapes for some of his propellers, together with notes on selecting and using them. Don's was the first range of fibreglass racing props made in Australia, and was gratefully received by modellers tired of reworking and breaking wooden props.
Propeller manufacture was always a part-time enterprise for Don, to be fitted in with the full time job he worked and a bit of time spent on his own modelling projects. At the peak of production Don would lay up a batch of props in their moulds early in the morning before leaving for work, and in the evenings he would remove the mouldings and clean them up.
The blades of Don's props were always thinner than those of ones produced elsewhere. To achieve this, Don paid special attention to cutting and placing the glass fibre rovings that provided the reinforcement. Each prop contained a predetermined number of strands, each cut to a predetermined length.
3. This page of notes deals with the location C.G. (centre of gravity) in relation to what Don calls the "pivot" in a control line racing model, and concludes with the assertion that models fly fastest when yawing slightly in towards the centre of the flying circle. Presumably, the "pivot" Don refers to is the bellcrank pivot.
This theory is controversial. Other analysts have maintained that the bellcrank pivot can be placed anywhere convenient, as in any yawing in or out of the circle the model pivots about the control line leadouts/guide at the inboard wingtip. Analysts who maintain that a model produces least drag when flying tangentially to the flying circle point out that if a model is initially yawing slightly in towards the centre of the circle it will yaw to fly tangentially when whipping is applied by its pilot. With a bit of whipping, this setup will certainly be the fastest.
4. Design sketches of a refuelling/shutoff valve Don developed.
5. Don never got around to implementing this idea for a carby in any of his racing engines. A venturi placed within a larger venturi was expected to produce powerful suction and vapourisation of the fuel.
6. Design sketch of tank mounting position for an FAI teamracer with SuperTigre rear induction engine.