The Breitling Chronomat manual and some links
The Breitling Chronomat is unique for the circular slide rule.
Mine is a bit scratched so here's a nicer photo from
as well as this delightfully enthusiastic description:
The Breitling Chronomat with its rotating slide-rule was patented in 1941 as war raged through Europe and other parts of the world, its design offering a welcome respite from the plethora of military and military-inspired watches of the period. The Chronomat's emphasis on engineering and mathematics, science and industry seemed to offer hope for a future when the war would be over and reconstruction could begin.
To summarize the manual for the 'Type 42' circular slide-rule:
The Navitimer's 'Type 52' slide-rule
- The outer CI scale is read CCW and is marked
- telemetre at 1.2 for
the speed of sound (1,236 kilometers per hour).
- at Pi
- The inner D scale is read CW and is marked
- red "S" at 3.6 (for 360 seconds) at top dead center
- with a red arrow and red "H" at 1.0 (at the 26.6 second mark)
- red "minutes" at 6.0 (for 60 seconds)
Differences in the slide rules:
inner (face) has concentric scales for
- hours 1-12
- 60 seconds (in 1/5 second ticks)
- slide rule D scale
- 6.0 at top dead center, '1' around 13 seconds
- "NAUT" at 3.3
- "STAT" at 3.8
- "KM" AT 6.1
- outer C slide rule scale (also read cw)
versions have red triangles
on the inner dial for 1.0, 3.3 "NAUT", 3.6 (probably for 360), 3.8 "STAT", 6.1 "KM"
outer dial (ALSO read CW): 1.0 3.6 6.0
- is intended to match the
E6B Flight Computer
Since the stop watch's second hand extends all the way to the slide rule,
I figure there's got to be some method of setting the outer ring
so the second hand acts like the cursor of a circular slide rule
to point directly to some calculation.
- The Chronomat's inner "D" scale has 360 at the top,
the moving outer scale is "CI" (inverted single decade counter-clockwise)
- The Navitimer's inner "D" scale has 60 at the top,
the moving outer scale is "C" (single decade clockwise)
- Chronomat history
shows other Chronomats with 1.0 top dead center (near the bottom: 1973, 1975)
Does anyone have directions for that?
Here's the manual for the Breitling Chronomat sliderule: