Basel Preview: Longines Twenty-Four Hours

Longines Twenty-Four Hours

In the 1950s Longines supplied watches to the Swiss national airline, Swissair. These timepieces, developed specifically for aviators, had a distinctive 24-hour dial. This feature met the needs of navigators who, at the time, had to determine the position of the aircraft and set up a flight plan. Longines will re-issue this watch with the official launch at Baselworld 2011. The new version has been given the name Longines Twenty-Four Hours.

In 2009, Harry Hofmann, a retired navigator from the old Swissair, visited the Longines Museum. He took advantage of this visit to present the company with a Longines watch that he used to wear when he was working for Swissair. This watch is one of those Longines created for Swissair navigators during the 1950s.

An original Longines aviation watch from the 1950s.
Longines original aviation watch

The watch that Harry Hofmann wore when he was a navigator for Swissair, flying DC-4s, DC-6s, DC-7s, DC-8s and Coronados up until 1974, bears the number 8237331. It is fitted with a Longines caliber 37.9N with a center seconds hand, which had been designed in the 1940s and used in Longines watches intended for pilots. The back cover of the steel case of Mr Hofmann’s watch is engraved with the Swissair brand-name. Longines’ archives reveal that it was one of a series of 70 pieces manufactured between 1953 and 1956 exclusively for the Swiss national airline. Technically, it is related to the aviator’s watch – the Longines Weems Second-Setting model, produced in 1927, or the Lindbergh Hour Angle watch made by Longines from 1932 on.

The modern Longines Twenty-Four Hours is fitted with caliber L704.2, a self-winding movement with hands that make one full circle of the dial in 24 hours. The stainless steel case has a diameter of 47.5mm; the dial is matte black with 24 white Arabic numerals coated with Super-Luminova and has a railway-track minute circle. The hands coated with Super-Luminova, and the watch has a center seconds hand, like the original model.

The date aperture is located at 3 o’clock. A sapphire glass covers the dial, and this timepiece also has a transparent caseback, with its own cover. The inside surface of the cover is engraved with the words “Re-edition of a Longines navigation watch exclusively made for Swissair navigators, 1953-1956“, plus the watch number. The Longines Twenty-Four Hours is mounted on a black alligator strap and is water-resistant to 3 bar (30 meters).

Technical specifications appear below the images, which may be enlarged with a click.

Longines Twenty-Four Hours
Longines Twenty-Four Hours

Longines Twenty-Four Hours
Technical specifications

Reference number: Longines Twenty-Four Hours, L2.751.4.53.x

Caliber: Self-winding mechanical movement
Calibre L704.2 (ETA A07 171)
16½ lines, 24 jewels, 28,800 vibrations per hour
48-hour power reserve

Functions: Hours, minutes, seconds, date, 24-hour circle on dial

Case: Circular, stainless steel, Ø 47.50 mm
Engraved and numbered back cover (unlimited series) on top of a sapphire glass

Dial: Matte black
24 white Arabic numerals with Super-LumiNova
Railway track minute circle

Date aperture at 3 o’clock

Hands: Skeleton pear steel hour-hand with Super-LumiNova
Skeleton leaf minute-hand with Super-LumiNova
Stick with drop counterweight seconds hand

Water-resistance: 3 bars (30 meters)

Glass: Sapphire with non-reflecting coating

Bracelet: Black alligator with buckle

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  1. Stefaan BOGAERT

    I have no Longines watch.

    But I had the opportunity to have Harry Hofmann as Astronavigation-instructor for my Swiss Airline Pilot Licence.
    I was afraid when I saw the marthematics involved in this course. But Harry Hofmann managed to make this course so interesting. The result: I passed the exams, and more important: more than 20 years later, I am still interested in astronomy. I am retired, and I am the happy owner of a Meade 200 mm telescope.
    Thanks for everything Harry Hofmann.

    Captain Stefaan BOGAERT (ret.)

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