Luftwaffe 3rd patern Flight Navigation Computer (Dreieckrechner DR3 Tp). The Luftwaffe used two different models of manual flight navigation computers which were basically circular slide rulers to assist in navigation calculations. This is the 'DR3 Tp' type which is having a hole in the center so it could be used as a protractor (Transporteur in German) as well. The flight navigation computer is having a diameter of 15cms. The computer is not visible maker marked or dated, this is a late war example produced in 1944/1945. Rare original 'DR 3' example in very good condition!