Mechanical chronographs: how do they work?

[e635815]

At the moment, I have a quartz Traser Chronographs.
Very easy to use: one button (2 o'clock) to start the chrono and the same to stop it. And the other button (4 o'clock) to reset the counters.
When I do reset them, the hands spin around clockwise until finding their initial position.

This left me wondering what would happen with a mechanical chrono? Do the hands do the same? Is that what is called the flyback complication?
Some manufacturers (Tudor etc....) propose Flyback and non-flyback chronos, I can't figure out what is the difference between the two options?

Can someone help?
Thanks and regards
Philippe

[marcosgt]

They work the same (mostly) as a quartz one.

Flyback, someone may correct the details, means that when you stop the timer, the second hand flicks back to the 12 o'clock position, whilst a secondary dial continues to count on, allowing the second hand to time 'laps' and the secondary dial total elapsed time.

At least, that's how it was explained to me

M.

[mrmr96]

http://en.wikipedia.org/wiki/Flyback_chronograph

[yeti]

marcosgt said:

They work the same (mostly) as a quartz one.

Flyback, someone may correct the details, means that when you stop the timer, the second hand flicks back to the 12 o'clock position, whilst a secondary dial continues to count on, allowing the second hand to time 'laps' and the secondary dial total elapsed time.

At least, that's how it was explained to me

M.

That's a Rattrapante or 'split seconds' chrono.

A 'Flyback' is one that you don't have to stop, you can just reset; press the reset button while the chrono is running and all hands reset to zero with the the timer re-starting instantaneously. It's primarily for pilots but I like using it, it's useful if you don't really want to read the precise time of your last event and want to restart instantly.

EDIT: Just re-read what you wrote; what you're describing is a Flyback Rattrapante which may or may not exist

Yes a Flyback 'flies back' to 12 (resetting hours, minutes and seconds) and then continues but a Rattrapante stops the 1st second hand (so the time can be read off) while the 2nd second hand continues to time a second event. Of course ALS have a split minutes timer as well, but now we're getting fancy

Edited by yeti on Tuesday 8th October 16:26

[Variomatic]

e635815 said:

At the moment, I have a quartz Traser Chronographs.
[...]
When I do reset them, the hands spin around clockwise until finding their initial position.

This left me wondering what would happen with a mechanical chrono? Do the hands do the same?

Others have already exlained the difference between flyback and non-flyback chronos - essentially that you can reset a flyback while it's still running and it will carry on timing immediately from zero.

In terms of "how they do it", the hands on a mechanical chrono don't "wind" themselves round like a quartz when you reset. They'll take the shortest direction back to zero, whether that's clockwise or anti-clockwise. So, say you reset when the seconds hand is showing 29 seconds or less, it will turn anti-clockwise back to zero because that's shorter than carrying on round the dial. If you reset at 30 seconds or more, it'll go clockwise.

The reset will take a fraction of a second, rather than the several seconds that (most*) quartz chronos will take, because the hands are disconnected from the rest of the train during reset and moved by a spring-loaded hammer hitting the side of a specially shaped cam.

• There are a few quartz calibres out there that use a mechanical reset and they'll act the same way.

[BOR]

Variomatic said:

They'll take the shortest direction back to zero, whether that's clockwise or anti-clockwise. If you reset at 30 seconds or more, it'll go clockwise.

Hands up who's just tried that.

[e635815]

These are crisp and clear explanations. i still don't know if I prefer (need!) a flyback function but I am out there looking for Tudor's chrono.
See you soon with pictures of my new acquistion.
Philippe