The next stage in the development of the Pilot’s watch really focused around World War Two although things started moving a few years earlier.
During the 1930’s the geschäftsführer of the International Watch Co. of Schaffhausen in Germany was one Ernst Jakob Homberger. Herr Homberger’s sons were both extremely interested in aviation, to the extent that in 1936 they persuaded their father to manufacture IWC’s first ‘Special Watch for Pilots’.
A highly advanced watch for the time, it housed the Calibre 83 movement, a very early shatterproof crystal, an antimagnetic escapement and a rotating bezel (drawing on Weems’ earlier design). The USP of the first IWC Pilot’s watch was superb reliability in extreme conditions and it was resistant to temperature fluctuations from minus 40 to plus 40 degrees Celsius. At 55mm, it was also very large…
IWC made 1,000 watches which were all supplied to the Luftwaffe, setting the mould for the Pilot watches that we know and love today. They also shaped the design for the iconic Pilot watch of The Second World War – The ‘B-Uhren’.
B-Uhren stands for Beobachtungs-uhren, literally translated, ‘Observation Watches’and they were used by the navigator on German Luftwaffe bombers during their devastating wartime raids. They were mainly made in Germany by Hanhart from 1939 and then by Tutima Laco, Wempe, Stowa, A. Lange & Söhne, and IWC Schaffhausen. The B-Uhren borrowed heavily from the original IWC design with their 55mm cases and pocket watch movements surrounded by a faraday cage to prevent magnetic interference.
As with the Weems method, in flight the navigator would receive a signal from the airbase at one minute intervals, setting its chronometer to the standard time of the German Naval Observatory. If the navigator’s watch differed from this then he would adjust the time using the now familiar onion shaped, long stemmed crown.
The B-Uhr was strapped onto the navigator’s wrist over the flight jacket by means of a long, double-riveted leather strap, much sought after these days in their own right.
The dial of the watch was of the familiar bold design – black with white, highly luminous Arabic numerals and large blued sword hands.
There were two different dial types:
The Type A – A standard design with Arabic numerals and a large luminous triangle with two dots at 12 o’clock. This was used to determine the orientation of the ‘plane so the navigator knew which way was up.
The Type B – A Chapter Ring dial with big minute numerals from 5 to 55 on the chapter ring, and a smaller sub-chapter ring marking the hours.
The classic large pilot’s watch design was so important that you can still buy B-Uhren from IWC, Stowa and Laco as well as others.
The next and final instalment covers the post war years and the advent of passenger flights