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What's the historical origin and/or practical purpose of the triangle with 2 dots on either side of the apex at 12 o'clock on B-Uhr and flieger watches. Other types of watches have the triangle, which makes sense from a visibility standpoint, but never the 2 dots. I've been wondering for a while about this distinctive feature found almost exclusively on aviation watches, but haven't gotten around to asking anyone.

I'm hoping on of the experts here can enlighten me.

Thanks and Cheers,

John
 

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Re: B-Uhr Question

Not really an expert here, but my best guess is that both the triangle, and the dots, respectively, were means to facilitate the upward orientation of the watch in the dark, and that the two features were combined on the B-Uhr dials.

Although I should say that the B-Uhren are, in my humble knowledge, among the first watches that facilitated the upward orientation of the dial by symbols (which would become a standard practice toward the end and after WWII). The German aviation chronographs had luminous numbers, but no symbols to mark the 12 position.

The American A-11 watches (or those with with lume) had two vertical dots instead of one to mark the 12, and the British WWWs towards the end of WWII had two horizontal dots, subsequently replaced by the upwards-pointing triangle.
 

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Re: B-Uhr Question

Not an expert, as well as Crusader, but I have a mind about this. The triangle at 12:00 of B-Uhren could had been used for indicating roughly the North anytime the watch was used as a solar compass. This symbol had been commonly used in many compasses for indicating the North.
To use a watch as a solar compass is quite simple: divide the present hour displayed by the watch in two (i.e.: if the hour hand of the watch points at 9:00 consider on the dial the radius between 4:00 and 5:00), then point the radius of the dial calculated above towards the sun. North direction is now indicated by the triangle at 12:00.
Of course, this method is approximated and do not takes in consideration the errors due to the EOT (equation of time, the civil time shown by a watch differs by the solar time moth by month. The correction to be made are known and reported on an abacus) and the local longitude (there is a correction of 4 minutes to be made for every degree of difference between the longitude of the position of the observer and the longitude of the central meridian of the local timezone of the observer, correction that is negative if local position is western respect the central meridian of the local timezone, positive if opposite).

The two dots, in my opinion, were used for aligning the second hand during synchronization of the watch with a master clock (i.e.: a radio signal).
All above are only opinions, I have no clues neither I'd been able to find any documentation...
 

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Re: B-Uhr Question

.....and what's about: "The triangle with the dots look really nice - well done design !":-!

I remember having read an article that confirmed Rouge's position: Pilots or navigators held the watch up towards the sun (or at night towards the stars) as a substitute for a sextant.The triangle was a device for aiming.b-)

Volker
 

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The triangle at 12?

Hi guys!

I´m new to both the form and to watches and I have a little question I hope somebody can help me with: What is the use for the triangle with the two dots at 12? Many pilot watches seems to feature this little triangle and I guess it ain´t there for cosmetic reasons.

I used the search engine but didn´t find any specific info about this triangle on the forum. However, if this subject has been covered already I apologies.

Best regards,

Claes
 

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Re: The triangle at 12?

Some answers here: https://www.watchuseek.com/showthread.php?t=115376&highlight=triangle [The two threads have meanwhile been merged.]

Funny you should ask, though - it so happened that I composed a bit of text on this very subject over the weekend, but unfortunately it is in German.

For the benefit of those familiar with the language, I'll post it anyway, and will try a translation later:

Grundsätzlich ist es so, dass das Muster der mit Leuchtmasse belegten Indices differenziert sein sollte, damit im Dunkeln eine Orientierung, welcher der Indexe die 12 repäsentiert, möglich ist. Man kann sich da in der Eile und im Dunkeln mal rasch um eine Stunde vertun - ist mir auch schon passiert. Da man früher manchmal nur die Indices, nicht aber die Zahlen auf dem Zifferblatt selbst, luminiert hat, bot sich an, den Index auf 12 durch eine andere Form gegenüber den anderen Indices hervorzuheben - eben zwei seitliche Punkte, oder alternativ ein Dreieck, das nach oben zeigt.

Bei der B-Uhr hat es dann aber einen klaren Fall von "Overengineering" gegeben, weil alle bekannten und eigentlich redundanten Möglichkeiten zur Orientierung des leuchtenden Zifferblattes zur Anwendung kamen: Die Zahlen sind luminiert, dazu noch ein Dreieck und die Punkte (normalerwiese eine Alternative zum Dreieck). Aber dieses Muster war vom Reichsluftfahrtministerium so vorgegeben.

Nicht alle Militär- und Fliegeruhren haben das Dreieck - in Deutschland die B-Uhr, aber nicht z.B. die gleichzeitigen Fliegerchronographen von Hanhart und Tutima. In Großbritannien wurde das Dreieck in den 50er Jahren, bei der 2. Zifferblattvariante der Mark 11 eingeführt - bis dahin hatte man dort doppelte Punkte zur Hervorhebung des 12er-Index verwendet, und das Dreieck wird noch heute verwendet. In den USA wird für den Index bei 12 heute eine andersfarbige Leuchtmasse verwendet.
So here is a rough translation:

Ideally, the pattern of lumed indices should not be uniform so as to permit orientation of the dial in the dark and to determine which index represents 12. In darkness, or hurry, one can easily be off by an hour unless the indices are differentiated. As in earlier times only the indices, not the numbers, were lumed, it was advisable to distinguish the index at 12 by a different shape - either two dots left and right of the index, or, alternatively, an upwards-pointing triangle.

The B-Uhren represent a serious case of over-engineering as all available and redundant types of differentiation were rolled into it: the numbers are lumed, there is the triangle plus the dots which are usually alternative to the triangle. This pattern was required by the German Air Ministry (Reichsluftfahrtministerium) in WWII.

Not all military and aviation watches have the triangle - in Germany the B-Uhren do, but not the contemporary aviation chronographs by Hanhart and Tutima. In the UK the triangle replaced the double dots in the the 2nd dial variant of the Mark 11 in the 1950s, and the triangle is still a feature today. In the US the index by 12 is marked by lume of a different color today.
 

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Re: B-Uhr Question

Hi there,

I received the following answer by someone over at Stowa regarding the triangle with the two dots. The message is in German. You'll find my translation below:

Grundsätzlich ist es so, dass das Muster der mit Leuchtmasse belegten Indices differenziert sein sollte, damit im Dunkeln eine Orientierung, welcher der Indexe die 12 repäsentiert, möglich ist. Man kann sich da in der Eile und im Dunkeln mal rasch um eine Stunde vertun - ist micr auch schon passiert. Da man früher manchmal nur die Indices, nicht aber die Zahlen auf dem Zifferblatt selbst, luminiert hat, bot sich an, den Index auf 12 durch eine andere Form gegenüber den anderen Indices hervorzuheben - eben zwei seitliche Punkte, oder alternativ ein Dreieck, das nach oben zeigt.

Bei der B-Uhr hat es dann aber einen klaren Fall von "Overengineering" gegeben, weil alle bekannten und eigentlich redundanten Möglichkeiten zur Orientierung des leuchtenden Zifferblattes zur Anwendung kamen: Die Zahlen sind luminiert, dazu noch ein Dreieck und die Punkte (normalerwiese eine Alternative zum Dreieck). Aber dieses Muster war vom Reichsluftfahrtministerium so vorgegeben.

Nicht alle Militär- und Fliegeruhren haben das Dreieck - in Deutschland die B-Uhr, aber nicht z.B. die gleichzeitigen Fliegerchronographen von Hanhart und Tutima. In Großbritannien wurde das Dreieck in den 50er Jahren, bei der 2. Zifferblattvariante der Mark 11 eingeführt - bis dahin hatte man dort doppelte Punkte zur Hervorhebung des 12er-Index verwendet, und wird noch heute verwendet. In den USA wird für den Index bei 12 eine andersfarbige Leuchtmasse verwendet.

Translation:

In the past, sometimes only the indices, but not the numbers themselves have been illuminated. Therefore the twelve o'clock position had to be marked differently in order to be clearly distinguishable. This was sometimes accomplished by two dots next to the index. Alternatively a triangle was used.

The B-Uhr is obviously a case of 'over-engineering': All known ways to help for orientation in the dark have been used: The numbers are illuminated, there is a triangle and it is accompanied by two dots.

Not all military and Fliegeruhren have the triangle. In Germany the B-Uhr, but not the Fliegerchronographen from Hanhart and Tutima. In Great Britain the triangle was introduced with the second model of the Mark 11. Until then, two dots have been used to highlight the twelve o'clock position. They are still used today. In the USA a different kind of luminous material is used for the twelve o'clock index.

Cheers
Stef

 

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Re: B-Uhr Question

Welcome to the forum Stef!

You will notice that the text is largely identical with a post above, which results from the fact that Stowa asked me to supply an explanation last week for an external question. ;-)

Nice to meet you directly on the forum. :-!

Edit: Come to think of it, I have merged the two threads on the same subject so that we'll have all the information in a single place. :)
 

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Re: B-Uhr Question

As ever, Crusader's given us a well considered and logical answer. I think it has to be exactly the reason he has outlined.

I'd wondered about this myself and in addition to the above, I thought perhaps it also facilitated hacking? I'm not up on the history part of it here, but does the appearance of this marker also roughly coincide with the appearance of hackable watches I wonder? Prior to the military requirement to synchronise watches, would this marker be so important - especially for night ops?
 

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Re: B-Uhr Question

As ever, Crusader's given us a well considered and logical answer. I think it has to be exactly the reason outlined here.

I'd wondered about this myself and in addition to the above, I thought perhaps it also facilitated hacking? I'm not up on the history part of it here, but does the appearance of this marker also roughly coincide with the appearance of hackable watches I wonder? Prior to the military requirement to synchronise watches, would this marker be so important - especially for night ops?
Interesting question, Ian.

AFAIK, the B-Uhren are indeed among the first examples to have the triangle, but they would not be hacked during flight, but only before.
 

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Re: B-Uhr Question

Interesting question, Ian.

AFAIK, the B-Uhren are indeed among the first examples to have the triangle, but they would not be hacked during flight, but only before.
Even though they wouldn't be hacked during flight - I imagine that the crews would often be in low light and towards the end of the war especially, many of the aircraft were moved from the aerodromes out into the countryside in hastily prepared strips.

Even without low light - a nice arrow marker that is easy to see allows much more accurate time setting than perhaps just the standard 12 and small indices. It allows exact alignment of the seconds hand with the 'mark' position at the tip of the arrow, for synchronising a watch to a master time signal. The two dots I feel, would further assist in cenralising the seconds hand at the correct position - as a visual aid.

Just my thoughts which might have been a factor on the design, but as I say, I'm not fully conversant with the design and history of the B- Uhr watches beyond a general level.

It's an interesting design feature when you stop and think about it!:think:
 

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I think it is quite natural to perceive a quickly forward moving object (especially an airborne one) as a forward-pointing arrow. ;-)

One would have to check a book on old cockpit instruments to find out whether the arrow was used there brior to watches.

There is a triangle on the bezel of my WWII cockpit clock, but like the triangle on a dive watch bezel, it is pointing towards the dial. The 12 on the dial is just that - the numerals 1 and 2.
 
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