Luftwaffe Dreieckrechner DR 2 Flight Computer Fl.23825 1942

This is an authentic Dreieckrechner Flight Computer, Model DR2, Fl.23825 as used by pilots and navigators of the German Luftwaffe during WWII. 

It is essentially a two-sided slide rule. Side one is used to correct the course of flight due to wind direction: by setting the black arrow to the desired course and rotating the white inner dial to the wind direction in black, then correcting the course by turning the aircraft to the corresponding red angle. We believe that side two was used to determine the impact of wind direction and speed upon aircraft flight time by adjusting the outer and inner white dials along the black dial. 

This 6-inch metal and plastic device, made in 1942, is in reasonable condition given its age. The dials on the front and back center rotate. The outer dial on the back does not rotate due to a slight dent on the outer metal ring but could probably be repaired, and the middle ring has a hairline crack that does not affect operation.