Shortround6
Major General
It was my understanding that the French Purchasing commission requested the Wright GR-1820-G205A, which had a single-stage, 2-speed supercharger, that was rated 1250hp.
The British Martlet (G-36B) had the P&W R-1830-S3C4--G (rated at 1,200hp.)
They did.
Except those are the powers (both engines were 1200hp, the wright was not 1250hp) for take-off and/or low gear.
The 1200 hp on the Cycone was good to 4100ft (4 digits) at some point above that the engine was shifted to high gear and that peaked at 1000hp at 14,000 ft (no ram) so there was no power advantage compared to a Hurricane I.
The P & W engine could make 1200hp at 4,900ft in low gear. High gear was 1050hp at 13,100ft according to one source
The two stage engine made 1000 hp at 19,000ft so obviously the single stage planes are going to have rather less performance at altitudes in the high teens and twenties.
They are not a way to get F4F-3 performance early.
Once the Hurricane gets 12lbs of boost the American engines 1200hp at low level advantage disappears. Since the Hurricane could run 12lbs before the BoB even started the Martlets don't bring much of anything to the fight that isn't already there (without the use of the time machine