The variation of power with height of a Merlin 46 engine as determined by flight tests on a spitfire Vc

Abstract

The variation of full throttle engine power with height was required on a Spitfire Vc (Mellin 46) for comparison with that obtained previously by the same method on a Hurricane II (Merlin XX). This, the locked propeller method, gives the ratio of full throttle powers at any two altitudes and in the present tests the ratio was obtained at the following altitudes :- 37,000 ft. and 16,000 ft. 35,000 ft. and 16,000 ft. 83,000 ft. and 16,000 ft. 37,000 ft. represents the maximum height at which accurate performance measurements can be made with this aircraft.