Because operation of the boost control cutout with 100 octane fuel should allow +12 psi boost at 3000 rpm, which should give about 1100 bhp at sea level, rising to 1310 bhp at 9000'.
At present, the Spitfire I can only achieve the 87 octane rating of +6¼ psi boost at 3000 rpm which should give 880 bhp at sea level, rising to 1000 bhp at 15500'.
As I explain in this thread, operating the cutout should produce roughly +17 psi boost with 87 octane if the power lever is fully advanced, leading to rapid engine failure. At present, operating the cutout doesn't do much unless you're flying a Spitfire II.
The Spitfire II can get about +8 psi with the cutout operated, which would give 1000 bhp at sea level. However, it gets the sort of performance I would expect from a Merlin XII at +12 psi boost.
It's been a while since I tested the Hurricane. However, since it also has the Merlin III, logically the Hurricane I and Spitfire I should exhibit identical engine behaviour in all respects other than coolant temperatures (since they have different radiators).
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05-11-2011, 07:52 AM
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