Intake burnt, oil gasket leak.

[Azimech]

I do remember reading multiple times that when the Luftwaffe changed tactics from attacking airfields and aircraft industry to bombing cities, they lost the BoB. Because they stopped when RAF resources were almost depleted.

But, other historians dispute that and say the Luftwaffe could never have destroyed the RAF.

One thing is for sure: looking at which plane was the better is pointless, since there are so many factors that were unfavorable for the germans. The RAF had the higher morale, the Polish RAF squadron was one of the best and most motivated due to their anger and superb pre-war training. Defending territory means no capture when having to bail out. Ditching in the channel was another unpopular risk for german pilots, including the lack of drop tanks until late in the Blitz, prior to that having the need to keep one eye on the fuel gauge and the other on the sky. The abundance of B4 fuel when everyone wanted C3.

If the situation were reversed, i.e. Germany on the island and Britain in continental Europe, attacking Germany, the outcome would've probably been the same, victory for the people on the island. Because in the early stages of the war the hardware wasn't that different.

The discussion which engine was better is IMHO a matter of personal taste. I like fuel injection, I adore the brilliant and elegant variable hydrodynamic clutch driving the supercharger on the DB series, but those designs didn't provide the edge over the Merlin. Critical altitude for the DB601 was 5,5 km, why so low puzzles me at this time. If I'm not mistaken the Merlin had better high-alt performance.