[Shikhov]

Thanks a lot especially to Mark & Kurfurst for very interesting info.

But seems too early to make a final conclusion what was the 601Aa.
I'm completely satisfied of 601Aa installation on Bf109E-7 detailed example.
Quite strange plane - used Arado E-1 airframe (3380-3664 block) and equipped with rare enough Aa engine produced 3 years before.
Great example, but may be exist some more?

As far as I understand 1168 is the total Aa/Ba number were produced. Some of them were installed on Swiss and Jugoslavian Emils (153), may be some Do215B were also equipped. Abt. 1000 of rest DB601Aa were on LW hands.
Therefore a figure apeared 1000/4000 E = ~ 1/4 (like Olivier already showed).

Many thanks to Kurfurst for work and new documents - DASA sheets for DB601A-0, A-1, Aa, N. But new question was born - when tables was printed ? It seems in same time no later then mid of 1939.
Please compare with Auszuege aus Fl.datenblatt Bf109E-1, E-3 nach L.Dv.556/3 powercurves (p.22) and Tabelle.
DB601A in Dec.1939 in their final condition was enough different as if for 1937.

From another side as we can see DB601Aa really developed since 1936 and therefore no matter for auslandisch version of A-1 can't be at the time.

Paid attantion for more point:
DB601N offer too little performance growth compare with DB601Aa for
30-min settings:
Aa at 1,27 ata 1050 hp (4100 m) in manuals for foreign cust. 1025 (4200 m)
N at 1,35 ata 1050 hp (4800 - 4900 m)
I can't see difference and any reason for using highly expensive (5 times) and available in small quantity at the time 100 octane C-fuel if LW has on hands so powerfull and reliable engine as DB601Aa.

Seems something wrong in this story.

All the best.

Igor.