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

[Crumpp]

Well there you go.

I am sure that did not magically happen either. I believe one of the other snippets talks about measures to prevent the cylinder head cracks that appeared during the test in the form of replacing existing parts with new ones that were not prone to cracking.

That probably paved the way for an increase to 5 minutes.

Either way, the notion of +12lbs being using continuously is pure fantasy.

However, I previously provided a quote:

Who cares....

I am sure a few pilots on all sides rolled the dice and took their chances by violating limits placed on their engines.

We hear about the ones who gambled and won. Those who did not win are not around to tell their side of the story.

Facts are, according to the FAA's statistics in aircraft accidents, not adhering to published limits is a factor in ~85% of the engine failures in aviation accidents.

Believing that pilots routinely violate published limits is gamer thinking and not grounded in reality.

The above memo states that the endurance trials were successful and prompted the recommendation for the use of 12lb boost ASAP.

Ahh, no the trials were not successful. They pointed the way to modifications which allowed +12 to be used for 5 minutes just like the previous Emergency rating of +9lbs. In comparison most endurance trial engines have tolerance issues or things like worn supercharger blades. They don't have cracked cylinder heads like in the case of the Merlin trials.

...the life of the Merlin engines under the emergency 12lbs boost conditions should be very little reduced from the normal, it being observed that the Merlin XII engine has been type tested and approved for 12.5lb boost take off conditions.

Yes...Normal being the life of the engine in comparison to using +9lbs of boost for 5 minutes. It is not the gamer notion that 12lbs could be used continuously. It is just as the FC directs, when used, it must be dead-lined and cleared by a mechanic for return to service.