Cheetah XVII 1948, 385 hp (287 kW) at 2,425 rpm. Cheetah XVIII 385 hp (287 kW) at 2,425 rpm, carburettor modified for aerobatics. Cheetah XIX 355 hp (265 kW) at 2,425 rpm Cheetah 25 345 hp (257 kW) at 2,425 rpm, Cheetah XV uprated to 475 hp (355 kW) at 2,700 rpm, modified constant-speed unit.