However, Metrovick refused the offer, and no amount of effort on the part of Armstrong Siddeley or the RAE would change their opinion.

[2] Now highly interested in jet propulsion, Armstrong Siddeley began looking for other designs they could work on, and eventually hired Fritz Albert Max Hepner.

The main difference between Hepner's design and Griffith's was that the stages were not connected to a central shaft, but instead to a surrounding rotating shell.

Another major critic of the concept was Armstrong Siddeley's chief engineer, Stewart Tresilian, who had grudgingly taken the post in 1939 at the request of the RAE.

[3] The Armstrong Siddeley board fired Tresilian in January 1942 and submitting their latest design proposal; once again it was rejected.

From there it fed into 11 flame cans arranged around the outside of the compressor, flowing back past the inlet, and finally through the turbine.

The ASP conversion used a second turbine stage to drive the propeller through a gearbox, producing 3,600 shp, as well as 1,100 lbf (4.9 kN) of leftover jet thrust.