Effect of boost control cutout prior to +12 psi boost modifications

[Seadog]

These are test results from 1939, showing that a Merlin III could be run for many hours at 12lb boost:



In the above test a Hurricane was run at 4.25 and 12lb boost for 20min and 5min repeatedly and only terminated at 49.5 hours when a glycol leak developed, by which time the engine had been run for over 8 hours at 12lb boost.