Helvetia 1930/40s Pilot Watch

Helvetia started producing pilots’ watches in about 1932. They were approximately 41mm in diameter and were powered by an adapted 16 Ligne pocket watch movement the calibre 51S. Helvetia fitted these first watches witha variant of the Depollier/Brun shock protection system that they had been using since the late 1920s in their sports watches.
By the end of 1934 the 51S movement had been superseded by the slightly amended 51-10 version and the shock protection replaced with the Helvetia’s own system patented in 1929. 

 The cases were usually made of chrome plated brass and had a hinged inner and outer back cover. They also had large fixed lugs for passing through a long, wide strap that could be fastened over flying clothing if required.
The case came in rotating and non-rotating bezel versions. The rotating bezel version had a pointer attached to the inside of the bezel under the glass. This could be used to keep track of time elapsed which was used as a navigational aid by pilots. The larger 41mm case with the rotating bezel was numbered 7011. The rotating bezels have a knurled surface to make it easier to grip the bezel for turning 

To mark this new range of watches Helvetia adapted their standard logo with the addition of a propeller. Initially this was static below the name but in January 1933 they registered their famous spinning propeller logo.

During the 1930s a variety of dials were in use but after the start of World War 2 the majority of watches seem to have been of the standard style with the numerals 1 to 12 fully illuminated and fitted with ‘Cathedral’ style hands. By the mid 1930s a thick glass crystal also started being used, this was to help minimise condensation due to the change in temperature when flying at altitude .

Description:

Year: 1939

Case: 41mm, Chrome plated

Bezel: bidirectional

Lume: Radium

Glass: mineral

Movement: 51-10