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

[ICDP]

Originally Posted by Seadog

An aircraft might fail if run too long at 12lb/3000rpm, but then again it might not, and failure is not an automatic consequence, and in fact unless the engine has suffered battle damage it probably won't fail if run until fuel exhaustion, but of course running out of fuel is likely to ruin your day, in any event.

Exactly, pushing too far for too long COULD lead to consequences a pilot would not like to face. That is what I want modelled, not some arbitrary limit of say 5 minutes = bang, conversely I do not want it modelled that I can run at +12lbs boost constantly without some potential consequneces. Your whole point seems to be that a Merlin could run at +12lbs boost until the fuel ran out. No pilot in real life WOULD EVER do such a thing from take-off until landing.

Originally Posted by Seadog

Regarding the Spit Vc test:

You will note that the test made allowances for increased temps during English and Tropical (IE Egypt) summers.

Read what I said again. My point was that at 12,000ft or 24,000ft it is easier to keep an engine cool than at SL. Had the test been done at SL the temperatures would have been much higher. Or to put it another way, flying full power +12lbs boost without taking circumstances and consequences into account is not possible. It is silly to assume there would be no potential issues running +12lbs boost until the fuel runs out.

Originally Posted by Seadog

Dowding did take his pilots to task for probably abusing the use of 12lb boost:
http://www.spitfireperformance.com/dowding.pdf
but this was only one facet of abuse that could lead to engine failure, as Dowding's memo points out, but RAFFC had lots of spare aircraft and engines, and I doubt that pilots felt that they were using 12lb boost unnecessarily.

OK, where did I say we shouldn't be allowed to use +12lbs boost? Also what use is a spare engine sitting in a workshop when you are 12,000ft over enemy territory? Like it or not the pilot notes have engine limitations for a reason, yes they may be conservative numbers but it doesn't mean they could be ignored.

These engines required carefull attention, not constant but they certainly weren't balls to the wall and forget about the consequences.