Luftwaffe Dreieckrechner DR2 Flight Computer

In addition to mechanical and electrical radio directional navigation aids, the Luftwaffe also utilised two different models of manual flight navigation devices, which were essentially a two-sided slide rule. One side is used to correct the course of flight taking into account the wind direction. This was achieved by setting the 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 angle. The reverse side was used to determine the impact of wind direction and speed upon aircraft flight time by adjusting the outer and inner white dials. These instruments were referred to by flight crew as 'Knemeyer' after the inventor Siegfried Knemeyer (5 April 1909 – 11 April 1979), who was a German aeronautical engineer, aviator and the Head of Technical Development at the Reich Ministry of Aviation during World War II. The earliest examples of the DR2 date from around June 1936 with the latest being dated November 1942 and the model subsequently evolved with the introduction of the DR3, first introduced in March 1943. Interestingly no records have been found to indicate a DR1 ever existed.

Our DR2 was manufactured in February 1940, so it almost certainly was in use during the Battle of Britain and was manufactured by the instrument maker DENNERT & PAPE in Hamburg, Germany and carries Fl no 23825. Whilst the instrument is complete, the alloy outer rim shows signs of corrosion, as shown in the attached images. Both the compass and calculating sides remain in good issued condition but with signs of service use. Sadly, the history related to this instrument has been lost, but it seems likely it could haven been wreck recovered. Some dealers might create spurious provenance about a named Battle of Britain crash site but we prefer to tell it as it is. The metalwork, despite the corrosion is entirely stable and having clearly had a service history it would still sit happily in a Luftwaffe or Battle of Britain related collection and is priced to reflect its current condition. The Luftwaffe flight chart shown is for illustrative purposes only and is not included in the sale. Measures 6" diameter (15 cm)