Radiator/cowling flaps

[horseback]

In First Light, Geoffrey Wellum didn't seem particularly worried about WEP usage at all.

As I recall, First Light was about the Battle of Britain and the early part of the war; I don't think that water injection -type boost was available in Allied fighters until mid-war. Water injection for the R-2800 in P-47s, Corsairs and Hellcats was introduced in combat around the winter of 43/44. I'm not aware that it was ever available for Allison or early single staged Merlin powered fighters.

In the early part of the war, I believe that War Emergency Power was simply that last little bit of throttle where the engine was asked for its maximum output where damaging it was much more likely. Taking a high powered engine to its full limits increases wear & tear tremendously, and one of the big factors in that wear & tear was the increased heat and friction, which could cause the engine to fail sooner (or right away, if it was just about due for overhaul). Water or methanol injection cooled the engine that critical extra bit and allowed you to pull that extra few horsepower when you needed them.

cheers

horseback