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Flyback vs. Rattrapante
John recently started a thread with this post:
There were various responses, many of which were clear enough, but they conflicted with one another. I thought I would summarize what the various responses said, and then list a few remaining questions.
First of all, several people (including me) pointed out that there were two different systems designed to help measure intervals that occur in quick succession. I liked Feder Haus's post the best:
There was some disagreement about whether the term "flyback" can only be applied to the chronograph function, or whether is applies generally to any function in which the indicator returns to a home position. Mike Margolis said that "flyback" applies only to chronographs, and similar mechanisms as used elsewhere (e.g., date) are called "retrograde." Watchbore, on the other hand, said that the term "flyback" can be used for functions such as dates. (He didn't mention the term "retrograde" in his post, so we won't know his take on that term until he tells us.)
In a response to Feder Haus's definitions (quoted above), Watchbore said that he calls the first term a "retour-en-vol or instant restart chrono." If I understand the rest of that post, he seems to use the term flyback only for the instant return of a hand, a property that all chronographs share. That is, they all fly back, but some non-instant ones need to be stopped first. I'm not sure Watchbore's distinction is widely shared, but it could be.
An advantage of NOT using the term flyback when discussing chronograph functions is that the term DOES have various meanings to various people, and when you use the term you run the risk of having readers misunderstand what you are trying to say.
As further evidence of this confusion over the meaning of flyback, I noted in my post that Watches Annual 1998 uses the term "flyback" to refer to one watch, the IWC Doppelchronograph, which is clearly a rattrapante. And, another, the Blancpain Flyback Chronograph even uses the term in the name of the watch. (Can we seriously accuse Blancpain of misusing the term?)
After I made my post, I looked up the description of the Doppelchronograph in my IWC catalog, and nowhere could I find the term "flyback." Instead, the text just emphasizes the watch's "doppelness," with phrases like "two-timer" and "when one stopwatch isn't enough but two are unnecessary." They don't use the terms "rattrapante" or "catch up," but instead say that the split second hand "synchronizes" with the main hand.
I also asked what the use of a "instant restart chrono" was, since I didn't see how you could read the time if the hand is going to fly back. Walt Odets explained that there are occasions in flying when you need to limit an operation to, say, two minutes, and if you complete it within the limit you then want to immediately begin timing the next interval. You aren't interested in how long the first interval was.
So, where are we? I conclude the following from the posts:
1. "Rattrapante," "split seconds," and "double chronograph" are all well defined and clearly refer to the case where there are two chronograph second hands, one of which can be stopped while the other continues.
2. The term "flyback" has different meanings as applied to chronographs, and may also be applied to non-chronograph functions. So, it is not a useful term, since one who uses it can't control what meaning it is conveying. If you see a watch described as being a "flyback chronograph," you should not assume it is a rattrapante unless you can see two chronograph second hands.
3. We don't seem to have a generally-accepted term for what Watchbore calls a "retour-en-vol." Hats off to him for recognizing the problem and adopting (or, perhaps even coining) this term.
4. For general use, most people who need to time intervals in rapid succession need a rattrapante. Retour-en-vols are useful only in special circumstances. (Well, maybe my bias is showing here... pilots would consider what they do as ordinary, and timing laps as a special circumstance!)
I don't know about you, but the preceding is very clear to me. The questions remaining are:
If I get some additional information on TZ, I'll update this web page.
After posting the above on TZ (5-July-1998) I got the following replies:
Posted by Tom P on July 05, 1998 at 18:04:08:
I have always understood the meanings of Flyback and Rattrapante as Feder Haus defined them. I just looked up the terms in two watch books I have, The Complete Price Guide to Watches and Watches a Handbook and Price Guide. Here is how they defined them:
The Complete Price Guide to Watches
Watches a Handbook and Price Guide
Flyback Indication - A hand moves to indicate, for example, the time or the date, along a segment of a circle (1 to 12 or 1 to 31) and then springs backward to its starting position when it reaches the end of the scale.
I know this doesn't help much, but it's all I have right now.
Posted by Michael Friedberg on July 05, 1998 at 19:10:37:
I'm rushing right now (on vacation), but some quick answers/comments:
1. Retour en Vol (return in flight, I believe) is the original term for the Flyback function. It obviously is French and still used in France (or for that matter, French speaking Switzerland, where most mechanical watches are made).
2. Rattrapante and Doppelchronograph mean the same thing, and differ from a Flyback
function, as Feder Haus as defined. However, some Rattrapante chronographs use a flyback
function (I believe the Dubey patented mechanism from
The Flyback really was a specification used for military flight chronographs originating, I believe, in the 1940s. Several vintage pieces --Hanharts and Type 20s (see my archive posting on the original Type 20)-- had it because the governments specified it, as a useful device for timing sequences as you've described.
Interestingly, despite one earlier post the Flyback function is not an expensive complication. Essentially the stopping arm is at a angle, so the inital pressure pushes the "brake" and the second part of the arm then resets the mechanism to zero when the pressure is released. (If I get good enough at digital photography and Photoshop, I'll illustrate this on my Lemania movement Type 20...wait a few weeks). It only seems like an expensive function since only two expensive chronos have it today (Breguet and Blancpain, although I think some Dubey models also might). I"m not sure, however whether a 7750 can be easily modified, which may be why you don't see it much.
It's an interesting complication, but not really special or useful for most of us. But its military flight heritage makes it interesting.
Hope this helps. There's a little about this in the book Chronographs -To Stp Time, also.
[Added by MJ after above messages.]
I meant to comment on the book, "Chronographs: To Stop Time," by Lang and Meis. This book has an incredible amount of detail--almost enough, it seems, to build your own chronograph movement. Unfortunately, the book doesn't use the terms "flyback," "rattrapante," or "doppelchronograph," or, at least, I couldn't find them. This is perhaps because the book was translated from German. (This reminds me of eating in a French restaurant and being offered the "soup of the day". In any other restaurant (outside of French-speaking countries), it would be called, in English, "soup du jour.") The book, however, does explain the one-button, two-button, split-second, single split-second, and chronostop chronographs.
Also, some additional comments about the three watches mentioned earlier:
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Last Updated: 19-Jul-2003 05:04:35 PM