There are two strands to the history of the aircraft gas turbine engine and jet propulsion in Britain. One strand has been told by Sir Frank Whittle (figure 1), the inventor of the turbojet engine, in Jet - the story of a pioneer (1953). 1 The other, less well known, was started by Dr Alan Arnold Griffith 2 (figure 2) of the Royal Aircraft Establishment (RAE). In 1926, in a report entitled ‘An aerodynamic theory of turbine design’ 3 , he proposed the use of a gas turbine as an aircraft power plant. In October of that year he put his proposals to a small committee from the Air Ministry and the Aeronautical Research Committee, which expressed itself unanimously in favour of prelim inary experiments. Accordingly, two sets of experiments were started. The first was on a stationary cascade of aerofoils and was reported by R.G. Harris and R.A. Fairthorne in September 1928 (figure 3).4 The other was on a model comprising a row of turbine and compressor blades of 4 inches outside diameter, mounted on one shaft and tested by sucking air through the blading (figure 4). From measurements of the losses, the efficiencies of stages could be deduced. The results, reported by W.C. Clothier in December 19295, showed that a maximum efficiency of 90% was obtained and an efficiency of 88.3% at a pressure ratio of 1.16.