Perk this one:
Boscombe Down Early 44 LF IX JL165
Merlin 66, full span wings, 7,400 lbs 150 octane fuel allowing +25 pounds boost for periods not exceeding 5 minutes.
In order to improve the IXs performace it was recommended that 150 octane fuel be used, thus permitting increased boost. For this modification the engine mounting had to be strengthened; a 24-25lb boost gauge fitted; a throttle gate fitted to limit boost to 18lb if the aircraft was refueled with 100 octane and a gate limiting boost to 14 1/2lb fitted to prevent 25lb being used for take off. The exhaust manifolds burned out rapidly but the shorter life was accepted by the RAF.
Performance test with 150 octane fuel
Height Top Speed Time to climb mins Rate of Climb ft/min
2,000 360 0 m 25 s 4,725
4,000 364 0 m 50 s 4,730
6,000 364 1 m 15 s 4,735
10,000 370 2 m 6 s 4,745
13,800 389 . 4,350
20,000 388 4 m 30 s 3,450
30,000 380 8 m 17 s 1,950
