Russian Mig Clock
The ACS-1 aircraft clock is one of the most fascinating clocks I have found, not only because of its military application, but also because of its complications. It was made for the fastest and highest-flying Soviet/Russian fighter jet planes (such as MiG-23, MiG-25, MiG-29 and Su-27), original Russian Air Force issue, and produced by Molnija, Мопния, (Chelyabinsk Watch Factory), in Chelyabinsk, Челябинск, east of the Ural Mountains, about 1500 km. east of Moscow. It has a timer and a seconds chronograph. The top dial shows the number of hours and minutes that, for example, the pilot has been in flight. The bottom dial shows the minutes and seconds elapsed, in a separate and independent stopwatch. I found the first two photos on the internet. The first photo shows where the clock was mounted in the aircraft.
The knob on the left is for winding and setting the main clock, turning the knob counterclockwise to wind it, and pulling it out to set the time. This knob, when pushed all the way in, will start, stop and reset the top stopwatch.
The knob on the right will similarly start, stop and reset the bottom stopwatch, when pushed in. When turned clockwise, the main clock is stopped. When turned back, the clock starts again.
The upper dial says Flight Time, ВРЕМЯ ПОЛЕТА. The lower dial says Sec., Cek, because it is a seconds chronograph.
The numbers on the back plate indicate that this clock was made in 1967, during the Soviet Era. On the back plate are the parts for the bottom stopwatch. The center gear and the stopwatch gear, to the left in the photo, have long steel shafts to mount the second hands on.
The stopwatch must be partially disassembled in order to service the clock.
Here you can see the stopwatch gears with their heart-shaped cams to reset to zero. Also shown is the bridge with the friction spring for the gear with the second hand.
Once the plates are removed, you can see the gear train of the main clock. Next to the escape wheel is the detent to start and stop the main clock by stopping the motion of the balance wheel. Particularly interesting is the use of two large mainspring barrels with stopworks to prevent the mainsprings from being overwound.
The front plate shows the parts for the top stopwatch. You can see how both stopwatches are independent of one another, built on separate plates.
The balance wheel has a high quality hairspring with overcoil. According to information I found on the internet, this clock was "designed to withstand speeds of 1800 mph (2900 km/h), altitudes of up to 100,000 feet (30 km) and pulling 6G," but I did not see anything about the escapement that made me think this clock was more robust than pocketwatches or other clocks of similar size. What made this clock stand out was the extensive use of friction jewels and the high quality hairspring, which I expect was imported from Switzerland.
The Russian Mig clock was probably a copy of a Swiss clock. You can see the similarities in the photo below, which I found on the internet, of a Jaeger clock from the 1940s. While the Russian version may be a copy, it is very well executed a well worth adding to your collection of timepieces, and for a small fraction of the cost of a comparable Swiss aircraft clock with chronograph and flight timer.
Every collector should have a Russian Mig clock.
Setting the time on a mig. (jpg image.)
Service manual? (pdf file in Russian.)