Chronograph watch Flyback function allows for ideal restart
The key to a chronograph is the firmness of the lever
- A famous chronograph mechanism with flyback function, Valjoux cal.230
The flyback feature has always fascinated enthusiasts.
However, the flyback function was not particularly difficult to implement.
The reset hammer and carrying arm are connected with a "seesaw."
That's all.
- Chronograph mechanism cal.59
However, despite this, the flyback function has been said to be "difficult."
Why is that?
The main reason for this was the "seesaw."
There just wasn't enough space in the watch to make room for the seesaw.
The flyback mechanism allows the chronograph to be restarted without stopping.
The Longines 13ZN, released in 1936, was the first wristwatch chronograph to feature the flyback mechanism.
The design of the simple chronograph from the 19th century and the flyback are almost identical.
To reset the chronograph hands, a button must be pressed to activate the reset hammer.
At the same time, the reset hammer, which raises the reset arm, cuts the connection between the chronograph and the normal gear train.
There is no stop mechanism.
However, the origin of the flyback is a movement with a center second that can be reset to zero.
There are two conditions to be met in order to add a flyback mechanism to an existing chronograph.
The first is that it is a direct reset.
The indirect reset is used to charge the spring of the reset hammer.
To reset, you must press the start button and charge the lever.
Therefore, it is not possible to equip it with something like a flyback mechanism that can be reset without pressing the start button.
Another thing is that there needs to be enough space for the flyback lever that controls the flyback.
Gisbert L. Brunner, a well-known watch journalist, also states that the robustness of the flyback lever is important for a flyback.
He also advised Zenith when it made the El Primero a flyback model.
However, the El Primero with flyback (405B) does not have a flyback lever.
Where on this movement is the flyback lever?
- The French Air Force requested Valjoux to make a flyback chronograph mechanism, the Valjoux cal. 230.
The flyback lever is the heart of the flyback.
But the structure is simpler than you might think.
Like a seesaw, it acts as a connection between the reset hammer and the carrying arm.
The flyback lever is designed so that when the reset button is pressed, the reset lever moves and is pressed.
Normally, the connection between the gear train and the chronograph is cut because the reaction force from the lever movement causes the carrying arm to jump up.
- A famous chronograph with flyback function, cal.222
The key to resetting and cutting power at the same time is the flyback lever acting like a seesaw.
However, space restrictions made it extremely difficult to fit a flyback into a wristwatch.
The movement is already occupied by the brake lever, reset hammer, etc., so there is no space left to place a flyback lever.
However, most modern chronograph movements are equipped with this flyback mechanism.
How do they secure the space? In fact, the method is quite simple.
The flyback lever is forcibly placed on top of the existing chronograph movement.
However, this lack of space also posed a major problem for the flyback.
Stable feel thanks to the sturdy flyback lever
- The greatest chronograph in history: the Chronograph Cal.22
- The greatest chronograph in history: the Chronograph Cal.22
There is no space to accommodate the flyback lever, so there is no room for it and its handling.
Therefore, if you use the flyback lever too much, it will break.
So if you're thinking of buying a current model with a flyback mechanism, it's better to buy one that was designed from the ground up.
For example, IWC's in-house chronograph movements, A. Lange & Söhne's Datograph, and Panerai's 9100 series are examples of this.
We do not recommend retrofitting the flyback mechanism as it may cause malfunctions.
The only exception to this is probably Zenith.
The method of implementing flyback control on aircraft made in the past is the same as it is today.
The flyback lever is placed on an excellent base movement to turn it into a flyback.
However, since previous movements were not automatic, there was more space than there is today.
So, in theory, it was very durable and easy to handle.
Now, let me introduce two aircraft equipped with flyback.
First up is the Valjoux 222.
The basis for this is the renowned 22.
A flyback lever is attached to this base.
If you look at the way the lever is handled, you can see that the reset hammer and carrying arm are lined up horizontally.
By moving the reset hammer, the associated flyback lever is pushed downward.
What happens when a flyback lever is pressed is that it jumps up on the other side of the axis.
Then, push the engaged carrying arm upwards.
At this point, the connection between the chronograph wheel and the intermediate wheel of the seconds chronograph is cut.
- A famous chronograph mechanism with flyback function, Valjoux cal.230
- Longines vintage chronograph watches
- Longines' first flyback-only chronograph movement, Cal.13ZN
The straightforward operation of the flyback lever is one of the reasons why Valjoux flybacks have gained such credibility.
Valjoux made the flyback lever and the minute chronograph intermediate wheel receiver coaxial, which made it possible to provide an ideal flyback lever without impairing the functionality of the minute counter.
Valjoux later incorporated this technique into the smaller diameter 720A and the higher vibration version 235.
However, the Longines 30CH is used as a pure flyback watch.
- Specialized for flyback chronograph mechanism cal.30CH
- Longines vintage hand-wound chronograph wristwatch
The movement is installed from the beginning, so the flyback lever is not an afterthought.
There is something exceptional about its design.
Things like the reset hammer, brake lever and minute chronograph wheel bridge are safely kept aside to allow the flyback to function perfectly.
With the 13ZN, it was difficult to fit a flyback lever due to lack of space.
As a result, Longines reflected on the design and made changes, and to this day produces a variety of dedicated flyback watches.
However, if we look only at the design, there is no doubt that the 30CH stands out.
The 30CH is often overshadowed by the 13ZN and does not get much attention, but it is a truly modern chronograph movement.
The flyback mechanism continues to fascinate enthusiasts.
When looking at chronograph design, it is hard to find anything more intriguing.
The old flybacks are much more robust than the current ones.
However, the damage that a direct reset can cause to an older movement is by no means small.
Therefore, it is true that we do not recommend using this feature too frequently.
