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

[Seadog]

Originally Posted by Crumpp

The rest require replacing the heads and in some cases, rings as well as the required modifications to the fuel metering system. This work was performed at Service Inspection intervals. Do you know what that means?

The March 20 1940 memo clearly states that new built aircraft already had the internal engine mods:

http://www.wwiiaircraftperformance.org/ap1590b.jpg

Given the production numbers for Hurricanes/Spitfires and RAF operational and combat losses prior to the start of the BofB, it is extremely doubtful that any unmodded aircraft were still in front line service. Production during March, April, May and June, and July, of 1940 would have amounted to approximately 1500 Hurricane/Spitfire aircraft, or greater then RAF FC's front line strength at the start of the BofB.

The memo clearly establishes that all RAF FC Hurricanes/Spitfires were modded for Hundred octane fuel and 12lb boost prior to the start of the BofB.