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

[NZtyphoon]

The Merlin tested in the Hurricane ran for 8 1/2 hours on 100 Octane fuel at 12 pounds boost, but the test was terminated after 49.5 hours by a glycol leak into one cylinder. The document goes on to note that this problem was rectified by modifying the cylinder head joints, a modification which was retrofitted to earlier Merlins and would have been incorporated into later Merlins. ( paras 4 & 6)

"It will be noted from the Service reports that an approximate increase in speed, due to the use of emergency 12 lbs. boost, of 28/34 m.p.h. is obtained depending on the altitude flown up to 10,000 feet." (para 8.)

This most likely applys to both the Hurricane and Spitfire. Gleed, below, 19 May 1940, notes an increase of 30 mph for his Hurricane.

"The modifications to the boost control cut out to limit the maximum boost to 12 lbs. sq. in are simple and in hand (otherwise full throttle would give about 17 lbs. sq. in.)" para 9.