Modelling engine wear and WEP limitations

[Seadog]

Originally Posted by ICDP

EXACTLY

Most pilots would engage overboost during an emergency only. Once the danger was gone you would imediatley ease of on the power, because the next thing on your mind would be, lets not blow the engine... it's the only one I've got. Frankly, constantly saying +12lbs boost could be used without fear until the fuel ran out is ludicrous. The pilot manual and RAF memos explicity state that +12lbs boost was to be used in emergencies only and only for 5 minutes at a time. Do you think they set these limits for fun.

When you have an aircraft with 85 or gallons of fuel, fuel consumption is never far from your mind, and this will provide the disincentive to not use 12lb boost without justification. However, in fighting over Britain it will be the Luftwaffe pilot who will most fear "to pull the plug" and the tactical advantage to an RAFFC pilot is obvious.

Yet, the trials of, and the operational experience of Merlin engine was that it would run continuously at 12lb/3000rpm with little fear of failure as long as it was running with adequate cooling and lubrication.