The German term „Beobachtungsuhr“ goes back to pilot´s watches of WW II. Strictly translated it has to be an „Observer´s watch“ or „Observation watch“ but on most watch related fora you`ll read „navigator´s watch“, „pilot´s watch“, „B-watch“ or even „Flieger“, which is the expression I like most.
These B-watches have been made for the German Luftwaffe by only 5 manufacturers
A. Lange & Söhne
Laco (Lacher & Co)
Stowa (Walter Storz)
Wempe (Chronometerwerke Hamburg)
and contained high quality pocket watch movements:
Lange & Söhne: cal. 48/1
(due to limited capacities watches have been assembled by Huber/Munich, Felsing/Berlin, Schieron/Stuttgart, Schätzle & Tschudin/Pforzheim, Wempe/Hamburg).
Laco: Durowe cal. D 5
Stowa: Unitas cal. 2812
Wempe: Thommen cal. 31
IWC: cal. 52 SC (SC= „seconde central“)
The specifications of these watches had been defined by the „Reichsluftfahrtministerium“ (RLM) – Imperial Air Ministry (see attached file)
Due to those specifications all B-watches had the following features in common:
- A case diameter of 55 mm
- Marked on the back with FL 23883 (FL = flight, 23 = navigation)
- Equipped with large crowns in order to be used with gloves
- Hacking movement (the second hand stops when pulling out the crown / essential for a precise time setting)
- Breguet balance spring
- Regulated and tested as chronometers
- Long leather strap (to be worn on the sleeve of a flight jacket).
There have been two different types of dials (Pls. note: there are other figures available on the net. not sure whioch are correct)
Type A (Baumuster A) from 1940 to January 1941
a classic dial with numerals 1 to 11 and the triangle with two dots at 12
Type B (Baumuster B) starting in January 1941
Big minute numerals from 5 to 55 and a small inner circle with numerals for h, at the position of 60 min a triangle and a line on its top.
If your are interested in watches of WW II and their history I recommend to visit the hompage of Konrad Knirim (Militruhren: Collectors Site for Military Timepieces) .
The Stowa B-Uhr Baumuster B
A. Lange & Söhne, Baumusuer B:
Stowa, Baumuster A:
IWC, Baumuster A:
Laco Baumusuer B:
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