the Orpheus 701 had a 7-stage axial compressor driven by a single stage turbine. In 1957 NATO ran a competition for a light fighter design. All three finalists chose the Bristol Orpheus and as a result a substantial contribution towards the cost of the initial engine development was made available from the Mutual Weapons Development Program. The winner of the competition, the Fiat G.91R and G.91T, used Fiat-built versions of the engine. Other users, mostly trainers, soon followed, including the Fuji T-1, HAL HF-24 Marut, HA-300, and the experimental Hunting H.126 and Short SB5. For later civilian applications, the Orpheus was chosen, after use of two each on the prototypes, as an option on the Lockheed JetStar, Lockheed's Vice President and head of the famous Skunk Works, Clarence "Kelly" Johnson stating; "These Orpheus engines ... have been the best engines the writer has ever used in a prototype aircraft. They were and are so good that it was decided at an early date to make all Jetstars from serial number two up capable of using two Orpheus engines (as an alternative to four American units). The Orpheus version ... is fully competitive in performance (except with one engine out) and will be offered to those who want its lower cost, simplicity, and - at least for some time - reliability". Many companies in the 1950s were looking at ways of producing a vertical take off and landing aircraft. Michel Wibault had the idea of using a turboshaft engine to drive four large centrifugal blowers which could be swivelled to vector the thrust. Hooker's engineers decided on using the Orpheus gas generator to drive a single large fan that would supply air to a pair of rotating nozzles, while the exhaust flow from the Orpheus was split into two and would supply another pair of nozzles at the rear of the engine. This experimental system developed into the Pegasus. Licences to produce the Orpheus were obtained by Fiat S.p.A., SNECMA and - as the TJ37 - Curtiss-Wright. Variants Data from Jane's All the World's Aircraft 1962-63., Aircraft engines of the World 1957 BOr.1First run on 17 December 1954, rated at by Spring 1955, with for take-off later;powered the prototype Folland Gnat. BOr.2 for take-off BOr.3 for take-off BOr.4 for take-off (de-rated) BOr.6 BOr.11 Upflowed compressor enabled the BOr.11 to develop BOr.12 With a simplified reheat system the BOr.12 was rated at