Pilot’s timepieces have illustrious fathers: Flieger watches.
If you are a bit sensitive to the charm of vintage timepieces you cannot escape the lure of watches like the Flieger watches. What we call Fliegers were a kind of pilot’s watch built on specifications from the German Luftwaffe. However, they can be traced back to WWI, as we can see from the (huge) Flieger we see in the top image.
From their birth, they evolved following the development of planes, becoming the typical watch we stereotype today as the quintessential Flieger. Their actual name was “Beobachtungsuhren” or “B-Uhren” (observation watches).
The B-Uhren watches were used as a navigation instrument during the flight, and especially, as a backup device for navigation of the cockpit instruments failed.
The B-Uhren had very specific requirements
The main specs were the following:
Lumed indicators. The numerals were filled with a large amount of Radium-based luminous paste, so to be easily visible at night;
Very big crown. Big, and easy to manipulate even when wearing gloves;
The strap was long, sturdy and riveted. It was made to wear over the flight jacket sleeves.
The original manufacturers of Flieger watches
We know that only five companies manufactured the original issued Fliegers.
1 – A. Lange & Söhne – The most famous German company made a total of 6,904 watches between 1940 and 1945 using their cal. 48/1 . The watches were assembled by other companies like Huber (Munich), Felsing (Berlin), Schieron (Stuttgart), Schätzle & Tschudin (Pforzheim), and Wempe (Hamburg).
2 – Wempe – It was a jeweler turned watchmaker, and assembled a small production of B-Uhren mounting a Revue movement cal. 31. This production (it is said of less than one hundred pieces) is known by collectors as the Wempe Carl Thommen, Revue K 31, B-Uhr.
3 – Laco (Lacher & Co) – We do not know how many watches Laco made, but it used the Durowe D5 movement to make its Fliegers. The movement had a large (22 mm) balance and a simple regulator.
4 – Stowa (Walter Storz) – This company instead mounted the Unitas 2812 movement inside its watches, which has a better regulation system with a swan-neck adjustment. In February 1945, the Stowa factory in Pforzheim was razed by an Allied bomb raid.
5 – IWC – Last but not least, IWC made a total of around 1,000 B-Uhren for the German Luftwaffe using the caliber 52 SC (officially “52T-19”’ H6 S.C.”).
Apart from these companies, which made simple timekeeping watches, we we know that several chronographers were used. Some mounted Swiss movements from Omega, Longines, and IWC, but others were built on scope by companies such as Hanhart and Tutima.
Some technical notes
The big movements used in B-Uhren were sturdier and more precise than smaller ones: very roughly, the bigger a balance wheel is, the more precise a watch gets. Incidentally, these watches used modified movements that featured a central second hand.
This was achieved through design of a new caliber, or through a pass-through wheel mounted outside the main bridge that connected the second wheel to the center wheel pinion of the watch so to move the second hand.
What you see here is the Durowe movement – and it has been modified to add the centra wheel. Look at the additional bridge that has been added over the bridge of the center wheel.
This is a movement of high quality and precision, by the way: look at the huge balance bimetal wheel with counterweights. All the while, it lacks the the swan-neck regulator with a calibrating wheel that you see in the Thommen movement manufactured by Wempe above.
You can find much more about horology and its fascinating history in The Watch Manual. It is a thorough e-book that explains all the basics about watchmaking and its protagonists.