Triumph motor cycle engine, 1921.

This engine was designed in 1921 by Sir Harry Ricardo of the Triumph Cycle Company with the idea of producing an engine which could maintain maximum power at sustained high speeds. The engine was used on Triumph's Model R motorcycle, popularly known as the 'Riccy', which was ridden by Major Frank Halford, co-designer of the machine and an enthusiastic motorcycle racer, to set a new 500cc world hour speed record (76.74 mph) and a British one mile record (87.8 mph) in 1921.