DB601A-1 = Aa ??

[Kurfürst]

You can read a lot of things on Mike Williams site about Bf 109s, most of it being in very loose contact with the historical reality - to put it mildly, Mike likes to use material in a way to show his own version...

Speaking of the V15a report, he totally misquoutes it, claiming that it was operating above the limit - the original is quite clearly stating the engine was some 40 hp down on power (951ps developed), and they even give corrected curves for the nominal guarateed output but that one is ignored.

You can read the full report here : http://www.kurfurst.bravehost.com/

Same for the comments on 109E/N versions 'towards the end of the battle' - it's just totally untrue, they were there from before the Battle and so on, just one example. Similiarly it's claimed the 1-min ratings were not cleared until mid-1942 for the DB 601, on the basis of a strange logic that a mid-1942 601 manual shows them, and even if manuals from `39 and `40 were that list the 1.40/1.45 ata rating present were shown to both Mike and Neil, they just don't care about it. The 109G and 109K articles are even worser, and damaging as they create and spread new myths and misconceptions instead of clearing them up (for which they have the proper material available).

If I were you, I'd quickly forget everything I read in those three articles. It's quite a good site as far as the primary source collection goes, but otherwise just far too biased and manipulative. Qoutes from Olivier are only interesting for them as long as they help pushing the agenda.

Sorry for the rant, but the sooner you see through it the better.

DB 60x ratings from available material :

601A-1 : 1.30/1.40 ata
601Aa : 1.35/1.45
601 N : 1.35ata (higher was planned but not reached)
601 E : 1.3 ata, then 1.42ata (appears cleared start 1942)
605 A : 1.3ata, then 1.42ata (appears cleared Sept/Oct 1943)
605AM/ASM : 1.7ata, from Q1 1944
605DM : 1.75ata mid-1944

605DB : 1.8 ata from fall 1944
and (convertible engines)
605DC : 1.8ata, then 1.98ata from Feb/March 1945.