Born in Oberammergau. Son of the painter Prof. Michael Zeno Diemer. Trained as an engineer. 1912 Joined the Bavarian Lifeguard Regiment, then a flying squadron. Was a member of "Bogohl 8 " the bomber squadron operated by the Senior Military Command, with rank of Flying Officer. 01.07.1921 Joined Dornier in Friedrichshafen as test pilot and for trial flying of new aircraft. 1922 After Dornier's move to Marina di Pisa (Italy), worked as test pilot, head of the aerodynamics department and manager of the advertising department. - from 1935 on, worked exclusively as manager of the advertising department. Was editor in chief of the company newspaper "Dornier-Post" which appeared from the autumn of 1935 until July 1938. August 1939 to Ende 1944 : German Air Force.. Returned to Dornier and assumed charge of the suggestions scheme. End of March 1946 ceased to work for Dornier Functions at BMW - Test pilot for BMW. On 17.06.1919, flying a DFW F 37/III (experimental two-seater, often referred to as the C-IV) with a BMW Type IV aircraft engine, he set up a world altitude record of 9760 metres, reached in 89 minutes (though this was not officially recognised). 13.09.1919 Set up a world altitude record for a passenger aircraft (8 people on board, 6750 metres) in a Ju F-13 powered by a BMW Type IIIa aircraft engine (the pilot, however, may have been Moes). Died in Friedrichshafen, a town on the northern side of Lake Constance Bodensee in southern Germany, near the borders with Switzerland and Austria.