During WWII, he was the Technical Director who conceived and developed the BMW-003, a turbojet engine for the latest generation Luftwaffe fighter jets, such as the Heinkel 162, the Arado 234 and the Junkers 287.

“Hermann Oestrich”

-At the end of the war he was disputed by the English, Americans and French.

-The French were the ones who offered better conditions, and they also admitted him to their group of collaborators (see Group 0).

-They founded ATAR, in Rickenbach, hence the name "Atelier Technique et Aeronautique de Rickenbach".

-By agreement with Snecma, he occupied the Voisin facilities and he led his Group 0 as Technical Director from 1946 to 1950.

“Atar 101-V”

-The Atar 101 was the first product (V de Versuch or prototype).

-Since then until today there have been many ATAR versions  being its golden age when the Mirage took its variants -8 and 9K.

-He is the founder of the team that formed the “Atelier Aeronautique Rickenbach” or ATAR.

-They began studies with German engines such as the Junkers Jumo-004 and BMW-003.

-Apart from the Atar 101 line of turbines, which is the first known product, a turboprop has appeared that was still made in Munich in 1945. At that time it had not yet been decided to move to the Dornier factory in Rickenbach, near Lindau (in the occupied area by France) from where they would come into contact with the French authorities a little later to move to that country.

"Turboprop by the Oestrich Design Office"

-Between 1950 and 1960, he was Snecma's Technical Director, already in Melun-Villaroche, based on Blvd. Kellermann in Paris.