Military Timepieces of the Luftwaffe
IWC Fliegeruhr Cal. 52

The big pilot's watch of IWC produced for the German Airforce

listed by Jürgen King IWC, May 1999

Technical data:
Diameter of the case: 55,00 mm, including attachment: 66,40 mm, height of the case with glass: 17,40 mm, diameter of the crown: 12,60 mm, visible dial: 49,00 mm, dial: metal 0,90 mm thick, minute circle with bold luminous (radium) five minutes-strokes, hours indication with Arabic numerals, at 12h bold luminous (radium) triangle and two dots. Hands: blued. luminous (radium) second-. minutes- and hour-hands in stainless steel. Inside cover: stainless steel, bottom: stainless steel with the following printing: B-Uhr - Bauart: IWC - movement number - Anforderz.: FL23883 - Rostfreier Stahl - IWC-Probus-stamp and case number. Outside bottom: movement number, partial with the following printing in an octagonal 'BA 2690', middle of the case: engraved at the side with FL 23883.
In 1940 1.000 pieces of the big pilot's watch with case numbers between 1033201 and 1034200 were delivered to Siegfried Heindorf, Berlin/Germany.

The movement:
IWC produced 1200 movements, caliber 52T - 19'" H6 S.C., under the numbers 1013801 to 1015000 in 1940. 52T: movement construction with hand-setting by using the crown. 19'": diameter of the movement (our records show 19/22'"), The enlargement has been made possible with a bigger movement circle. H6: movement height in millimeter (6 mm) SC: centre second executed as in direct driving, with braking-spring at the fourth wheel pinion, jewels: 16 rubies, adjustment: swan neck adjustment, balance: sliced bimetallic balance with weight- and regulation screws, balance-spring with Breguet-terminal curve, escapement: Swiss lever escapement, decoration: gilt main plate, bridges and movement circle ratiated, engraving: IWC in an oval and movement number

Examination:
Controlled in 6 positions, control of temperature. The remaining 200 movements have been used for the English deck watches. Movement- and case numbers remain the same and the last four numbers of movement- and case number have been repeated on the dial.

BA 2690:
Stamp in black color BA = factory control, the stamps have been made by certified examiner, who has ensured that the watches, they have stamped correspond in their execution to those of the sample examination of the DVL: Deutsche Versuchsanstalt für Luftfahrt.

Fl. 23883:
Number of requirement 23 = navigation instrument, 883 = serial number given by the DVL (Deutsche Versuchsanstalt für Luftfahrt)