[olefebvre]

I never said the Aa was exactly the same as the A-1.
The export customers indeed get the Aa engine but the Russians got a/c with A-1 engines. The Aa documents leaves no doubt it was designed for export since there are absolutly no references to RLM standards within those documents (fuel, oil, doc ref, etc...).
The Aa was based on the A-0 just like the A-1, and used the old kind of supercharger as used on the A-0 but souped up for low alt business. It seems the increased take off rating was of interest for the Luftwaffe afterall since about 25-33% of the produced A/B series engines were of the Aa/Ba kind. Which means that the luft used them as well along with the A-1. Both subtypes being produced over the same period of time.

While there is absolutly no Aa document that i could find with a RLM reference, but i believe it was used most probably on the E-4/B and E-7 variants for which the increased output at take off was most needed.
So far every engine recovered on E-4/B or E-7 crash site seems to have been of the Aa type.

Cheers,
Olivier