An inventor has to be a mix of the visionary, an iconoclast willing to challenge the status quo, and a little bit mad. Dr John Archibald Purves, the man who introduced the world to the Dynasphere, dubbed the high speed vehicle of the future, seems to fit the bill perfectly.
So, what was the Dynasphere. Modern Mechanics in its June 1932 edition explained all. Inside the wheel, on either side, tracks run completely around. The motor is geared to the track so that, when the engine is started, the motor pulls the track toward it and so starts the wheel in motion. Centre of gravity is low to prevent the wheel from tipping over.
The weight of the motor and driver is sufficient to keep them always parallel with the ground—if the driving apparatus were sufficiently light, the motor might conceivably climb up the geared track instead of pulling it and the attached wheel around. Speeds of thirty miles an hour, with two occupying the seat, have been comfortably attained. The lattice-work in front of the driver’s eyes disappears when the wheel is in motion, flashing past so rapidly that he has a good view of the road he is travelling.”
Margaret Partridge, writing in the 1934 edition of Women Engineer noted that its controls were similar to those of “an ordinary car” and that its inability to skid was due to the fact that its propulsion was not dependent upon the “mutual pull between wheel and road”. In other words, Purves had devised a large monowheel that accommodated two people and was long lasting due to the lack of deterioration that friction creates. Partridge argued that its “mobility, economy, and efficiency” made it superior to any other vehicle around.
A filmed test drive was held on a beach at Weston-super-Mare in 1932, after which Purves claimed that the Dynasphere had “reduced locomotion to the simplest possible form, with consequent economy of power”. He had two prototypes, one with a 2.5 hp petrol engine, sufficient to propel the 1,000 lb wheel, and the other powered by electricity. In 1935, he developed a bus version, capable of holding more passengers.
Sadly, though, the car of the future had no future. While it moved perfectly well, it proved almost impossible to steer or brake. Perhaps even more disconcertingly, the Dynasphere was prone to the phenomenon of “gerbiling”, the tendency when accelerating or braking for the independent housing holding the driver within the monowheel to spin within the moving structure.
And so, the dream of roads filled with electrically propelled monowheels remained just that.
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