250 GG 'DVL'

this Leica 250 with an internal power shaft socket for use with the special electric motor drive was delivered to the DVL (Deutsche Versuchsanstalt für Luftfahrt - German Laboratory for Air travel in Berlin) for testing the ball bearing shutter in this camera (for condition to -45° celsius), 2 years later cameras equiped with such a ball bearing shutter and the electric motor were used in German fighter planes. The camera is engraved 'DVL A7/03685' on back of top-plate, vulcanite cracked but complete, top-plate synchronised, Summitar 2/5cm no.509376 - see VIDOM Special from October/2010