Spit1a > SpitII

[Kurfürst]

Originally Posted by Kwiatek

5. Comparitive speed trials were then carried out, and the Spitfire proved to be considerably the faster of the two, both in acceleration and straight and level flight, without having to make use of the emergency +12 boost. During diving trials, the Spitfire pilot found that, by engageing fully coarse pitch and using -2lbs boost, his aircraft was superior to the Me 109."

Both British and German flight test showed that Spitfire and Hurrciane could outturn 109, also Spitfire with CS propeller and 100 octan fuel was faster (at low to medium alts).

I think the dead give away in the British test is the finding that the Spitfire is faster in level flight, even with 6 1/2 lbs boost. Which it simply wasn't, take a look at the maker's performance curves or the Rechlin tests findings. However the French had already noted some DB 601 engine troubles with this 109E in 1939, as did the British later when testing Bf 110 and 109 in test report "Performance tests on a Me 110 and a Me 109 (DB 601 engines):

"Both airplanes were fitted with DB 601A engines which gave considerable trouble during the test. A marked falling off of power was noticed as the tests progressed and some of the most important results could not be repeated".