Filed by Whittle when aged 22 and training to become a RAF Flying Instructor. It shows the air passing through a two-stage axial compressor followed by a single-stage/single-sided centrifugal compressor thence entering a number of combustion chambers arranged radially around the rotor. Following combustion, it shows that the expanding gasses pass through a single-stage axial turbine on the same shaft as the compressor. Modern small gas turbines follow a similar layout. Once granted, the patent was published and became available worldwide. It lapsed in 1934 when Whittle found himself unable to afford the renewal fee of £5.