Hi -

Long time lurker, first time poster. I'm an American expat living in Germany and been collecting for a couple of years (around 40 working vintages, mostly Gruens but a number of Stowas from the 1930s as well), and I mod the vintage forum over at WatchUSeek.

I've got a question that I've not been able to resolve adequately.

The Benrus Sky King, with original dials, has three markings on the minute totalizer (the totalizer on the right) at 4, 8 and 12.

Now, there are plenty of chronos out there with markings at the 3, 6 and 9, which are usually explained as telephone timing markings.

But the 4, 8 and 12 markings are unusual. I know the Benrus Sky King was never an issued watch, but one rather popular with pilots when it was offered.

I've attached one picture (older seller's picture from eBay) so show the watch in question.

The only real plausible answer I've seen was from an Australian site where a flight navigation technique was discussed on how to find out what your true position when flying over featureless ground/ocean: if you are flying, for instance, a 270° bearing, fly 360° for 4 minutes, then 90° for 4 minutes, then 180° for 4 minutes, and then make a final 90° turn and check your heading. If it is not 270°, then you are being blown off course and need to adjust your flight path for how much you are off (i.e. if your final heading is 262°, then you need to fly 278° to compensate for the side winds pushing you off course).

But if that was the purpose, then the watch would need to be marked at 4-8-12-16.

Anyone have any idea what those 4-8-12 markings signify?

Thanks!

JohnF

John, Can't offer anything on your watch, but wanted to say that you picked a very nice place to settle in good ole Deutschland. I spent one tour in Frankfurt in the early 70's. At that time Oberstedten had a couple of nice gasthauses that were frequent hangouts. Remember that one was Zum Lowen. Can't remember the name of the other.

Tom

John,

I'm a bit confused. Although I've seen the 4-8-12 demarcation in the 30 minute register on vintage chronographs before (not just on Benrus), the image you've posted shows, I think, those marks at 3-6-9.

Are those the marks you're asking about?

If so, sorry, but I don't know an answer for the significance of those marks, regardless where they are found.

Cary

Hi John and welcome to the active posters group! I like your Sky Chief watch - did you mean to type Sky King or Sky Chief? It has a nice look to it and I would imagine it should be pretty accurate as well.

I've been a pilot for many years and I can not remember when I or any of my other pilot friends ever used a wrist watch for actual navigation. We always use the panel clocks in aircraft for low tech, seat of the pants flying, backups to the fancy navigation equipment. Panel clocks have much larger faces, tend to be very accurate, and get regular servicing and checking (unlike personal wristwatches). Also, trying to read the small dial of a wristwatch while the plane is vibrating and bouncing around, much less pushing tiny buttons and rotating watch dials and such is just too distracting compared to using the panel clock. I imagine that is why wrist watches issued by air forces have always been relatively straightforward rather than like the complicated watches sold on the commercial market.

I don't have any facts for why the 4, 8, 12 have extra markers rather than the 3, 6, 9, 12 as seen on of watches made by other companies but from my experience as a pilot I can not think of any particular piloting reason. My guess is they are there mainly for decoration.

The "old aussie pilot trick" you mention doesn't make any sense to me in that it is not one of the standard and simple ways a pilot would normally do a quick check on whether the wind may by blowing you off course. Also, just thinking it through I don't see how it would work. For example, lets say you are over the ocean with no ground references and you are flying on a westerly compass heading of 270 degrees. You turn right until you have a compass heading of 360 degrees (north) and fly for 4 minutes, then you turn right again until your compass heading is 90 degrees (east) and fly for 4 minutes, then you turn right again to a compass heading of 180 degrees (south) and fly for 4 minutes, then you turn right again by 90 degrees. Your compass will always read 270 degrees since you have made four 90 degree turns, all based on the compass. Could you explain the theory as to how this trick is supposed to work?

Hi -

As an update to this ancient post: the 4-8-12 markings have been definitively identified as used for navigational purposes. Take a look here:

http://newsgroups.derkeiler.co...007-09/msg00234.html

and this:

http://www.auf.asn.au/navigation/enroute.html

Unfortunately, that latter link seems to have disappeared. The relevant info was this:

7. If necessary "assess the wind!" Whilst over the orbiting landmark turn onto a quadrantal heading, e.g. north, and fly that heading for one minute then turn 90°, e.g. west, and fly that for one minute. Systematically scan the surrounds, for an identifiable landmark, starting with the area closest to the aircraft then moving out to the middle distance. Repeat for two more anticlockwise turns and after 4 minutes have elapsed you should arrive back near the starting point. If you have held to the headings and the timing then the ground distance and direction of the arrival point from the orbiting landmark should provide a reasonable estimate of the wind velocity. e.g. if the arrival point is about 1 nm north-west then the wind speed must be 15 knots from the south-east. Of course if you are a poor judge of ground distance [which applies to many/most of us] then the indicated windspeed is not calculable but at least you know the direction and have a gross indication of the speed.

Okay, that makes sense. You do need a definite spot on the ground as your reference, though.