Its original USAF designation was J47-21, but with innovative features including variable inlet guide vanes, double-shell (inner and outer) combustor case, and 50% greater airflow was redesignated J73.

The mass flow was increased by relocating accessories from the centre of the compressor inlet to the underside of the engine.

[1] The pressure ratio was increased and variable inlet guide vanes fitted to prevent low-RPM problems (rotating stall/blade flutter) with the higher design pressure ratio.

[3] Four J73 engines were converted to produce thrust using nuclear energy instead of jet fuel.

The engines were modified to pass the compressor air through a heat exchanger, in which heat was transferred from a nuclear reactor, before entering the compressor turbine at 1,400 degrees F.[4] Data from Flight 9 April 1954 : Aero Engines 1954,[6] Aircraft engines of the World 1953[7]Related development