Weems and the Luftwaffe: Hour Angle Watches by Longines, Lange, PP and V&C

Timing Instruments for German Aviation before WWII:
In 1933 the technical department of the German Aviation Ministry (RLM: Reichs-Luftfahrtministerium) tested the hour angle watch of
Longines based on developments by Weems and Lindbergh.
See the att. spec Luftwaffe document of the 'Zeitwinkeluhr' with 180° dial and 47,5 mm diameter (Fl 22604 of 1933) imported by Paul Baumeister Berlin.

At least the German Aviation Ministry changed the specs for the wrist watch to 55mm diameter for better readibility of luminous dial and the 360° indication. A practicle idea was to introduce a stoppable ‚second‘ hand (like a 'rattrapante'). This made it possible for one person to stop the indicator while performing the nautical calculation.

So in 1934 they gave orders for prototype wrist watch developments directly to A. Lange & Söhne and additionally by private importers to two Swiss manufacturers Patek Philippe and Vacheron & Constantin.
These three companies should develop two alternative models, one standard hour angle watch and one with addional rattrapante ‚second‘ hand.
A. Lange & Söhne shipped the first watch in silver case early in 1935.

Description of function:
The little hand makes 360 degrees in twenty-four hours, the big hand shows the angle minutes, the ‚second‘ hand rotates in 4 min.

See attached the Luftwaffe spec sheet for the Longines and the standard prototypes of the three manufacturers. The prototypes with the additional 4 min hand do exist and the Patek Philippe from 1936 was sold by Cristie's in 2009 for 1,8 mCHF.
⁣Gruss Konrad

Thats what is obvious. There were long discussions together with the Deutsche Seewarte (the German Naval Observatory in Hamburg), for ships chronometers as well, even to use 400° dials, at least this design with 360° lead to prototype developments of the Luftwaffe and for the Kriegsmarine with 180° dials. As a lot of tables, manuals and trainings would have to be changed, at least the start of WWII endet these developments and standard dial design was used.
I have no specific documents of the Luftwaffe development orders. Most of these were lost in air raids 1943 in Berlin and Hamburg.
Hour angle watch Kriegsmarine:

Hour angle chronometer Luftwaffe:

Very interesting information. Thank you for sharing!

Hallo friends,
I have no contact to the Patek Philippe archive and my good relations to Vacheron & Constantin were cut, as Richemont took over.
But maybe someone here can get the information:

• To whom did Patek Philippe deliver the watch with the movement no 170.383?
• To whom did Vacheron & Constantin deliver the watch with the movement no 412.066?

It was in or around 1936, though the movements were produced far earlier, and I expect a German importer.
Konrad