Inaccurate performance data for BOB fighters in COD comparing to RL data

[NZtyphoon]

24 September 1938:

Sir, I am directed to inform you that in order to improve the take off performance of Spitfire aircraft, the use of 100 octane fuel by squadrons equipped with this type has been approved.

2. Improvement in the take off performance of Hurricanes will be obtained by the use of C.P airscrews but there will be a period of some months before this modification will be introduced...

The report goes on to explain that 100 octane was useful as a means of improving take off power, particularly with the Hurricane on some airfields, and the operational limits in Merlin engines would have to be strictly observed. This is evidence that the adoption of 100 octane was well underway nearly a year before the war started albeit its use was temporarily restricted as a measure to improve take off performance; this was also before increased boost pressures were adopted.