What is an Aviation Watch? - A Personal View

[Crusader]

Draft Version (2004-08-04)

There have been repeated discussions on various fora "what constitutes a pilot's/aviation watch?" and "which is the ultimate pilot's/aviation watch?". I am not an aviator myself - and therefore free of a personal opinion -, though much interested in the tool-like character of aviation watches (as I will call them here). I have attempted to analyze the debate and to make an attempt to clarify a few issues.

In doing so I have drawn information from internet discussions by pilots and fans of aviation watches. I should point out that sometimes the views of e.g. general aviation pilots, military pilots and airline pilots differ quite substantially as they face quite different challenges in their respective occupations ? a fact to be kept in mind. All that is said here is, of course, only my personal view, and is based on my observations. All faults are solely my own, but any additions and corrections will be greatly welcome.


I. Different people talking about different watches ...

What, then, is an aviation watch? It is crucial to realize that a timepiece that is referred to as an "aviation watch" can be:

(1) either a watch that is primarily meant as a (backup) instrument on the flightdeck for use in actual flight operations,

(2) or a watch that supports the overall requirements (e.g. different timezones, alarm functions) of a pilot both on and, perhaps more importantly, off the flightdeck.

(I am not even including a third group, i.e. those actual or would-be aviators who use their choice of watch to communicate their pilot status to the general public according to what is perceived to be an aviation watch ...)

To understand that there are two sufficiently different, yet equally legitimate, concepts of "aviation watches" goes a long way towards explaining why there is a seemingly endless debate about the relative usefulness of particular watches as "aviation timepieces", or about which features constitute an aviation watch. It also goes to show that there can be no such thing as an "ultimate aviation watch".

Many different answers are possible to the questions asked at the outset. These answers tend to refer, however, ? sometimes confusingly for those not familiar with the field of aviation watches - to a discrete number of key features of aviation watches, and indeed to several distinct categories of watches:

- The plain watch with or without a simple rotatable bezel,
- The GMT-watch with an additional 24h time indication
- The chronograph in various forms with or without additional timezone
- The anaolg/digital multi-function (all-in-one) watch.

Discussion as to the merits of watches within a given category make much more sense than an apple-and-oranges debate across these boundaries, e.g. whether a plain, a GMT-watch, a chronograph or a multi-function watch makes for a superior aviation watch.

For reference purposes, and in order to facilitate the debate on aviation watches, I have attempted:

(1) to define the key features of aviation watches,

(2) and to classify the different kinds of aviation watches into "categories" and sub-categories (called "types" here).

(Please note that digital-only watches are not considered at all as differentiation between aviation and non-aviation types is next to impossible.)


II. What constitutes an aviation watch?

II.1. Key features (required and/or recommended):

There are some features that are more or less common to, and indeed essential for, almost all aviation watches. That is to say that all users would benefit to some extent from these features. In fact, these features make for a good, legible watch ? whether it is used for aviation purposes or not.

- a high degree of accuracy
- reliability
- ruggedness (i.e. basic water- and shock-protection)
- primary time display in analog format
- sweep (=center) second hand
- hacking feature
- clarity of design for good legibility during the day (i.e. maximum dial-hands contrast, usually black dial, white hands and frequently white Arabic numerals)
- sufficient lume on dials and hands for good legibility at night; the lume pattern should facilitate the correct orientation of the dial (12 up) at night
- absence of unessential and distracting features

And here is a range of features which I personally view as worthwhile and recommended characteristics of aviation watches:

- flush, non-catching case and bezel design
- non-reflective case-finish
- non-glare crystal
- anti-magnetic properties
- crystal secured against loss of outside pressure


II.2. Neutral design features:

I am neutral about overall size and weight. Some hold that a large dial size in the vein of the German WWII B-Uhren (which is easier to read, though accuracy rather than legibility was the reason for the choice of the original B-Uhren) is typical for aviation watches. On the other hand, small watches do not catch or snag in cramped cockpit conditions, and these smaller and lighter watches have a strong history, too, as issued military aviation watches (American A-11, A-17, DTU 2A/P, GG-W-113; British Mark XI, G10 et al.)

Some have argued that a big crown (originally necessary for setting time with gloves during flight) is characteristic of aviation watches, but since there are only very limited situations when this will be necessary, I am hesitant to view this as a design characteristic. Small crowns make for a flush design, e.g., and this may be preferable especially in a situation that does not require operation of the watch with gloves on. The crown position and the question of crown guards is equally unimportant, IMHO, except that for hacking purposes I would prefer the crown on the right hand side of the watch.

I am likewise neutral about the movement type (manual, automatic, quartz) and the case and crystal material, as long as the above mentioned criteria (e.g. ruggedness, non-glare finish) are met. Each movement type has its own advantages and disadvantages, and no clear trend in aviation watches is discernible. Much the same can be said for the case and crystal materials.

In the same vein, there are no typical aviation straps. Military aviators are very concerned about fire hazards and prefer naturally flame retardant leather straps or extra-long nylon straps that permit wearing the straps over the flight suit. The latter is obviously of no concern to airline pilots wearing dress shirts to work. So, as far as straps and bracelets are concerned, whatever suits the wearer is fine.


II.3. Complications - GMT, Chronograph, Bezel:

As for which additional principal complications are needed or helpful in an aviation watch, there is indeed much and heated debate. Two principal schools of thought are in evidence:

(1) One school of thought argues that a chronograph function is essential (as a back-up instrument for the onboard-timers), especially for instrument flying. In that case, a center-minute-totalizer is usually viewed as advantageous over a subdial layout, as is a flyback function. Sometimes the chronograph hands and/or subdials are kept in a different color to differentiate them from the regular hands. This school corresponds closely with those who view an aviation watch as an instrument primarily for aiding (or backing up) an aviator in actual flight operations.

(2) Another school argues that the most useful feature is a GMT function, as aviators must be able to track several timezones (e.g. local time, home base time, UTC) because aircraft logs, weather reports, air tasking orders etc. are frequently kept in different times. This school corresponds most closely with those who hold that an aviation watch is primarily a watch that supports an aviator both on and off the flightdeck.

Ideally, the first type is a true GMT watch and the second one a chronograph.

Please note, however, that both of these requirements can also be addressed - though admittedly only in a very rudimentary fashion - by a rotatable bezel on plain watches. The bezel can take the form of
- a second time-zone (12h) bezel,
- a time-elapsed or a countdown bezel, or
- a combined 12h/time-elapsed bezel.
The bezel of an aviation watch should be bi-directional as the mono-directional bezel is a key feature of dive watches (where it does make sense, as it is not a good idea to exceed the maximum dive time), but for aviation purposes ease of use should be of prime concern and hence the bezel should rotate in either direction. The bezel should ideally be marked with a luminous dot to facilitate use in low-light conditions.

Of course there are many watches which have combinations of these features, most notably the analog/digital multi-function watches. It is interesting to note that on these watches some pilots will indeed prefer those with an analog chronograph second hand (Breitling B-1) over those without analog second hand (Breitling Aerospace) or those with a permanent second hand only (Omega X-33). As far as timing seconds is concerned, analog is always quicker to read than digital - and time is critical in flight.


II.4. Optional functional features:

Then there are several additional features that are regarded as useful only by some users, and would not benefit all users:

- A day and/or date function may be quite helpful for planning purposes and the paperwork associated with flying
- A loud alarm is frequently mentioned, though not so much for use on the flightdeck but for wake-up during crew-rest and in hotels. If used on the flightdeck, it can be used to remind the pilot to switch to a different fuel tank ...
- Another feature frequently identified with aviation watches is the E6B slide rule. It comes in complete (including scales to convert hours and minutes to minutes only) and less complete versions. It is rarely, if ever, viewed as an instrument to be used in flight. It is, however, sometimes regarded as useful for pre-flight planning purposes. In sum, is a function not so much for the flightdeck but for the time a pilot spends away from the plane.
- For a chronograph, a center-minute-totalizer is considered far superior to a subdial layout as the minutes can be read very easily. A flyback function can ease the workload of a pilot, too, and will be very welcome for a pilot using the chrono seconds to time flight manoeuvers.
- An emergency beacon (available only on some Breitling watches) may be a useful feature for some pilots in general aviation, but can hardly be considered a general requirement for an aviation watch.
- A 0-100 scale can be used to compute e.g. engine run time (or other times which are given in decimal format). I am not sure about the usefulness of this feature, but some pilots appreciate it, just as the compass rose bezel, or a tachymeter scale as a backup instrument to establish ground speed. I would not view these features as essential for an aviation watch, but as very optional, depending on personal preference.


II.5. Conclusion:

Not all of the above-named features are present in all aviation watches, or can indeed be considered mandatory. In particular, the need for anti-magnetic properties and protection against the loss of outside pressure have been called into question. But the more of the required and recommended features (i.e. those mentioned in section II.1.) are present in a watch, the better, IMHO, as these features do not necessarily add to the technical complexity of a watch, but increase its reliability and usefulness. A degree of water-resistance, e.g., while not essential for flying per se, adds to the reliability of a watch as a pilot can approach his plane in a driving rainstorm (or even wash his hands) without endangering his watch.

Moreover, I find it important that one chooses for an aviation watch only those features actually needed. It can be said that the more mechanical features are present in a watch, the more opportunity for malfunction, and the more legibility and reliability are compromised. The simpler a watch, the more rugged it usually is, and that translates into legibility, availability and low operating costs. No point in a complicated mechanical GMT-Chrono-Alarm-E6B-watch that is prone to malfunction due to its complexity, or excessively expensive to repair. The desire for a maximum number of complications and optional features leads one quite naturally to the analog/digital multifunction watches as the additional functions do not add to the complexity of what is at heart a fairly rugged quartz watch.

Please keep in mind - in addition to whether the watch is aimed for use on the flightdeck or both on and off it, in according to the axiom formulated in the beginning of this article - that different types of aviators can incline towards quite different watches. A bushpilot flying a sparsely instrumented GA plane might favor a chronograph (as a backup instrument) with emergency beacon. An airline pilot - who has no need for a chronograph given the abundance of timers in an airliner cockpit - might prefer a GMT or alarm watch that helps him during his time away from the flightdeck and for keeping track of the multitude of forms and data in GMT-format. A military pilot, on the other hand, might place the greatest emphasis on instant legibility and ruggedness, and the accuracy and survivability of a watch in the case of his plane being downed.


III. An Attempt at Classification:

I have indicated a limited number of examples of the original and/or currently available watches of each category and type, but this does not mean at all that watches not mentioned here are not considered aviation watches. But the examples will suffice for the reader to know which category/type a given watch will belong to.

N.B.: A chronograph function will put a watch into a different category, but a flyback or split-time chronograph function does not - it is still a chronograph. Neither will a center minute-totalizer (as e.g. in the Lemania 5100), although, again, this can be viewed as a substantial advantage for a chronograph per se.


Category I, type A:
basic movement, no additional features
N.B.: Emphasis is on accuracy, legibility, and reliability.
Original: German WWII B-Uhren; American A-11, A-17 and Hamilton GG-W-113; British IWC Mark XI, Omega 53 and G10
Current: IWC Big Pilot and Mark XV; Sinn 656; Speedbirds I and II; PRS-53; Laco re-issues and other B-Uhren hommages; Bill Yao types 48 and 53; Glycine F-104

Category I, type B:
12h watch with additional time-measuring bezel and/or second timezone bezel
N.B.: basic 12h-movement with bezel that may be neutral, time-elapsed, countdown or a second timezone (12h) bezel, or a combination thereof. The bezel can be mono- or bi-directional.
Original: IWC Mark IX; Czech Air Force Longines; US Navigator watches
Current: Traser P6500, Luminox 3401, Marathon Navigator, Precista CAF hommage; O&W M-6, WCT M-16 II; Tutima Flieger Automatic; most basic diver watches


Category II, type A:
24h watch with additional rotatable bezel for second timezone
Original: O&W Early Bird, Rolex GMT-Master I, Glycine Airman

Category II, type B:
additional movement-based independent 24h indication
N.B.: can have additional time-measuring bezel, but not a second timezone bezel (see Cat. II, type C for that)
Original: n/a
Current: Sinn 856, Tutima Flieger UTC, IWC UTC, Rolex Explorer II

Category II, type C:
additional movement-based independent 24h indication with rotatable bezel for additional (3rd) timezone
Original: Rolex GMT-Master II
Current: Rolex GMT-Master II; Tutima Automatic FX UTC, Glycine Airman 8; Omega Seamaster GMT


Category III, type A:
basic chronograph, no additional features
Original: Tutima Military/NATO Fliegerchronograph; UK issued Seiko Chrono; Omega Speedmaster Professional,
Current: Tutima Military/NATO Fliegerchronograph; Sinn 756 and 356; Damasko DC 56/57; Speedbird 1903, PRS-5; IWC Fliegeruhr Chronograph Automatic

Category III, type B:
chronograph with additional time-measuring bezel
N.B.: bezel may be mono- or bi-directional, and of the time-elapsed or count-down type
Original: Tutima and Hanhart Fliegerchronographs; Type XX/XXI chronographs; Heuer/Sinn Bund chronograph 1550 SG
Current: Tutima Fliegerchronograph 1941 re-issue, Hanhart re-issue; Damasko DC 66; Sinn 142; Tutima Fliegerchronograph TL and F2 and Pacific Chronograph; Sinn EZM 1 and Sinn 103; many Breitling watches

Category III, type C:
chronograph with additional movement-based 12h or 24h indication (with or without additional time-measuring bezel)
Original: Omega Flightmaster
Current: Tutima Chronograph FX UTC and Fliegerchronograph F3; Sinn 756 UTC and 356 UTC

Category III, type D:
chronograph with additional slide-rule bezel (E6B)
Original: Breitling Navitimer
Current: Breitling Navitimer, Sinn 903


Category IV: Digital/Analog Multifunction
Current: Omega X-33, Breitling B-1 and Aerospace, Citizen Skyhawk/Navihawk series


IV. My personal favorites: :

I could not resist, and here is my list of personal favorites. H=handwound, A=automatic, Q=quartz

I-A: IWC Big Pilot (A), IWC Mark XII/XV (A), Hamilton GG-W-113 (H), Sinn 656 (A)
I-B: Traser P6500 Date (Q)

II-A: possibly O&W Early Bird (H)
II-B: possibly IWC-UTC (A)
II-C: Rolex GMT Master II (A)

III-A: IWC quartz-mech. Fliegerchronograph (Q), Tutima Military/NATO Fliegerchronograph (A)
III-B: Damasko DC 66 (A), Heuer/Sinn 1550 SG Bundeswehr-Chronograph (H)
III-C: see category IV
III-D: n/a

IV: Omega X-33 (Q)


Useful Links:

Time Flies on Pilot's Watches:
http://www.watchuseek.com/cgi-bin/anybo ... =2&gV=0&p=

Development of the Navigator watches: http://www.timezone.com/library/cjrml/c ... 2675690324


Many thanks to the members of TZ-UK and WUS-Pilot's Watch Forum for their comments!


Date: 4 August 2004

[Ming Thein]

A comprehensive list of watches indeed, thanks for sharing, Crusader. :D

I personally feel an avaiation watch, much like a divers watch, should be clear, legible, and instantly available to tell the time, but not built to withstand external pressure like a dive case. It should be non distracting, but instantly legible; the Sinn 656, 756 and 856 are exemplary in this regard, and to a slightly lesser extent, the Omega Dynamics.

Somehow I don't think I'd fly with a Skyhawk, it's just a bit too complicated - if I felt I needed a chrono, then I'd use the Speedmaster Pro or Sinn 756 (especially the new black version :D)

Ming

[swanbourne]

As we say up here in the north, "a right riveting read". Thanks for sharing Crusader, I agree with much of what you say.

Eddie

DELETED

[abraxas]

Thanks for sharing Crusader ... you are probably right but I will never know as I find ?lists? in general very confusing ... unless I am looking for something in particular.

I am glad you used the word ?aviation? instead of the more commonly ?pilots? as there many jobs which require timing on a large aircraft apart from stirring the damn thing ... navigation and bomb-drops being two that presently spring to mind.

'Aviation and watches' is like 'the chicken and the road' or even 'the chicken and the egg'.

I have looked into the subject myself and have countless files on my PC about it. I feel that ?generally? people used whatever they had on their wrist ... important functions tended to be taken care by on-board instrumentation, which also included timers and clocks, as we know. The few cases where a need for a piece is identified and the piece is made are golden.

In my eyes the definitive aviation pieces are the IWC Mark IX-XII in terms of quality and ?actual? usage.

Thanks for the effort.

john


c 1929. Between the wars. Time of romantic aviation, USA.

[Ming Thein]

Seconds are kinda illegible, but I guess the planes then were slow enough that it wasn't overly critical :P

Ming

[Crusader]

I am glad you used the word ‘aviation’ instead of the more commonly ‘pilots’ as there many jobs which require timing on a large aircraft apart from stirring the damn thing ... navigation and bomb-drops being two that presently spring to mind.

Bombing good! :P

Actually, I did use aviation instead of "pilot" because I was unsure about the correct spelling: pilots watch, pilot's watch, pilots' watch ... sort of like drivers license.

In German the term is "Fliegeruhren" which translates as "aviator watches". Perhaps one should anglicize the original word as fleigeruhren, then ... :twisted:

[Effortless]

Hi Crusader,

thanks for taking the time to compile this list. Fascinating reading. Pilots watches are a personal favourite of mine. I love stainless cases, black dials, luminous hands and high legibility. I love the IWC collection, and am lucky enough to own their Pilot Chrono (NOT Spitfire version!!). Other watches I own in a similar vein are my much loved Speedbird II, a Seiko Aviator chrono (quartz...sorry!!), Seiko Diver 6309, and one of those enormous Russian Navy diver watches, at 55mm dia. All of these on either black NATO's, or Rhinos.

I am looking to buy a IWC Mk XI...my all-time ultimate watch. Anyone know where one is for sale?

Regards,
Effortless.

[foversta]

That's a very interesting job. I have a Laco watch which belongs to my favourite catagory : category I, type A !

:wink:

[Ming Thein]

An even more comprehensive job, Crusader. Thanks and congratulations! :D

Ming

[abraxas]

Thank you Crusader. I know you love researching the stuff. :D

I wonder if we can differentiate between an airplane-pilot and a helicopter-pilot when it comes to wristwear?

I have no experience in either of these disciplines but it feels that a chrono would be more useful to a helicopter pilot ... or am I romanticising again?

You got me at it I am going to run a poll ...

john

[Crusader]

Thank you Crusader. I know you love researching the stuff. :D

I wonder if we can differentiate between an airplane-pilot and a helicopter-pilot when it comes to wristwear?

I have no experience in either of these disciplines but it feels that a chrono would be more useful to a helicopter pilot ... or am I romanticising again?

You got me at it I am going to run a poll ...

john

Don't know, but this is an interesting question. The UK issues chronos to fast-jet and rotary wing aircrew, but not to transports/maritime surveillance pilots. US issues non-chrono watches only, Germany issues - I believe - chronos only.

I'll ask on the pilot's watch forum.

First, I'll own up to being a pilot. The aircraft I fly range from minimally equipped where my watch is legally required instrument, to others where I want functions for convenience both on & off duty. I also fly into remote areas as well as cities. I've searched for years for a watch that is exactly what I'd like in a watch and I'm yet to succeed in spite of numerous purchases.

Crusader's post is good exposition of some of the problems.

Some items for my *ideal* - but yet to be realised - watch:

* Slide rule. Surprisingly I use this feature a lot. Not particularly in flight since I have a pocket size slide rule that's far more capable, but for anytime I need a handy calculator eg currency conversion when overseas, measurement system conversions etc. Mind you, I have used the slide rule in flight & for flight planning when I've forgotten my usual tools.

* Large face. Damn sight easier to read & also to fit the other functions legibly. Black face, Dayglo green/luminescent hands & numerals. As much luminescent coating as will fit, so no non-luminescent edging on the hands.

* 24 hour movement & face using an analog display, including a sweep second hand. Aviation works in UTC, family is in a different timezone so direct reading 24hr time is convenient. Hours marked 2, 4, 6,......,22,24 with a stripe for the odd numbers.

* Accurate mechanical movement, manual or automatic. Many of my jobs have taken me to areas where replacement batteries are not available. I've had a quartz watch suffer a flat batter while there. A right pain in the proverbial...

* Waterproof to 50 or 100m AND to reduced pressure as well. The crystal face must be set so that it is positioned below the level of the bezel edge (for protection). Also a flat, not convex, crystal.

* Timer: This is rather different to anything I've yet seen. I want a sweep second hand (can dual use the normal sweep if need be) that can be stopped & reset to zero with only a couple of presses, say, stop then reset then start., minute counter to be a **mechanical** digital display ie nothing electronic/LCD. The minute counter to consist of tens units (0-5) displayed in as large a window as possible to the left of centre and units (0-9) similarly displayed on the right. Numerals to be luminescent, same as hour numerals & sweep hands. Additional sweep hour hand for counting the hours using the 24 hr face. This gives nearly 25 hrs of counting AND gives a readily read display in minutes & seconds for instrument approaches . No need for fractions of a second. Also no need for a split time function.

* Day/date window below or above the centre. Doesn't *have* to be perpetual. Adjusting for months manually is acceptable although automatic is nice.

* Second time zone. OK for this to be done by having the normal display sweep to the other zone with a button press then sweep back to the primary with a second press. Alternatively a second sweep hour hand might be better. Not quite sure which would be more easily read. If shared hands then there MUST be a luminescent 'dot' or mark that appears when the alternative time is displayed.

* An alarm would be nice to have but only if it's possible with a mechanical movement. It's not worth moving to a batter powered watch for it.

Things not to be used:

* red ink for any of the markings. It's invisible under red cockpt lighting. Makes me laugh when I see 'pilot' watches with a red coloured second hand...

* Sub dials. The information is too small to be easily read. I used to have a fairly expensive Seiko but found the sub dial stopwatch to be as useless as tits on a bull.

* Sub windows must not overlap face numerals or stripes ie they must be sized to fit between the numerals & the axle.



Probably a bunch of other details that I can't recall, but that's the gist of what I'd like. Something like that is worth thousands of dollars to me.

[abraxas]

.
Tinstaafl, welcome and

thanks for taking the trouble to fill-us-in on your wants.

Things not to be used:

* red ink for any of the markings. It's invisible under red cockpit lighting. Makes me laugh when I see 'pilot' watches with a red coloured second hand...

This just killed me :lol: . I didn't know about it and there :( goes my love of red seconds.

Maybe you should get together with Eddie (the forum moderator and owner of http://www.timefactors.com/ ) and put together the ultimate 'Aviator'. :wink:

What watch are you currently using?

john


PS I posted this link sometime ago: http://biothinking.com/watch/ about slide rule watches. I must admit it's all beyond me.

[Crusader]

Welcome to the forum, T., and many thanks for your comments. I could see many points you are making, though I doubt that a mechanical watch can meet all your requirements. But there are quite a few features which have been quite in prominence in several discussions on the Pilot's Watch Forum, as well, esp. the need for a sweep second hand and a digital minute totalizer (actually that is the way the onboard clock is set up in airliners, and it is eminently sensible. It has been done in mechanical chrons inthe 1970s ... wish they did it today ...).

I hope you don't mind if I ask a few clarifying questions:

* Accurate mechanical movement, manual or automatic. Many of my jobs have taken me to areas where replacement batteries are not available. I've had a quartz watch suffer a flat batter while there. A right pain in the proverbial...

Also a flat, not convex, crystal.

I am fairly neutral on the quartz/auto/handwound debate ... I can see the advantages of quartz, and one of the main arguments against it is what to do when you run out of batt. power in a faraway place. I would not dream of using a quartz watch in the second half of the specified battery life, and I think that would cut down on the power failure incidents quite substantially. Likewise, I would give any watch (mechanical as well) about a month after it is back from repair or battery change to check that it works flawlessly ... had a Sinn 656 come back from repair with the balance dislocated, resulting in the watch doing 25h per day. :wink:

Why do you prefer flat crystals? Is that because of the reflections (a flat crystal can be tilted out of the reflective angle quite easily)? Whereas domed crystals have a higher impact resistance.

And do you prefer a certain type of crystal (acrylic, mineral, sapphire)?

G'day everyone,

abraxas, for the past number of years I've used a Citizen world time. It's a quartz of course and I've gone through several battery lives with it. The battery flaking out at awkward moments is always a pain in the arse.

The multiple timezones are nice, as are the two alarms but most of the functions are next to useless at night. Having to press a button to light the LCDs is not appropriate when I'm busy. You can't even see the LCD function indicator in the dark without activating the backlight. The backlight in turn only lasts a second or two then switches off. Very inconvenient because I end up have to guess how many button presses to cycle through to the desired function, then pressing the light. If not correct back to guessing again... :(

The bezel is rather tight on this one. Certainly more difficult to turn than my poor old Seiko. I wouldn't have this Citizen if I hadn't left my Seiko on the roof of my car as I drove off from some garage in the middle of nowhere about 10 or 15 years ago...

Another problem is that the bezel markings are painted on & use gold colouring against a black background. Not as good a contrast as white - or better - luminescent markings. The painted surface wears & scratches which doesn't do much for ease of use over time. Which reminds me of a spec. I failed to mention earlier: Bezel markings to be etched, not just painted on. Also for the markings on the two rings to mate ie not spatially separated otherwise the slide rule is ineffective.

Crusader, I find having to track the life of a battery just about on par with 'when did I clean the record heads on my VCR?' sort of stuff. It's noticed when it fails, if that makes sense? I much prefer a mechanical because winding a watch just becomes a habit (or it's an automatic :) ). LCDs displays can't be seen at night unless you press a button. A good luminescent display is easily visible under cockpit lighting so that adds to the argument for mechanical.

A caveat though, alluded to in my previous post: As long as the manufacturer doesn't get an attack of the marketing/fashion stupids and fails to use maximum contrast colours or limits the surface area that contrasts by using second colour outlines on hands etc.

You've picked the reason for a flat crystal. Domed crystals will nearly always have a reflective band at any convenient viewing angle. Flats need only a very small angle adjustment to remove any reflection. I'm aware of the strength benefit of domed vs. flat. That's one of the reasons for mounting the outside surface below the plane of the bezel. That would also help protect it against scratches & chipping. My Citizen has a flat crystal mounted slightly above the bezel plane. As a result the crystal edges are chipped to the point of no longer able to ensure waterproofness. Has a few scratches too but not as bad as my Seiko domed watch developed in a much shorter period of time.

I'm neutral about crystal composition. As long as it's bloody hard & strong!

It's probably obvious that I'm after a useful working tool, not some marketing/fashion drone's concept.


PS: Something else I neglected to mention in my earlier specs: a magnifying lens over the timer's 10s & units windows & over the date window to aid readability.


later...

Just a thought about quartz. One of the newer solar charged devices would work too IF everything else I've described is present. Not sure it would have the power reserve for all the mechanics though?


much, much later
I've just had a thought about an improvement to the counter/stopwatch function.

Have the sweep hours counter independent of the sweep seconds/mech. digital minutes counter. Have the hours counter able to be paused & restarted with two separate button pushes ie 1st push to pause, 2nd to restart. Long term times don't have to be too accurate for my purposes. Nearest .1 of an hour (6 mins) is ideal. Have a third counter window with 0 - .9 of an hour displayed digitally. Doesn't need the same immediate visibility as the minutes counters so a smaller size is suitable.

At the same time the independent seconds/minute counter able to be stopped & then reset with a first & second push on a different button to the hour counter. There isn't a need to count past an hour for the seconds/minutes counter.

T

[Fschwep]

Great overview, Crusader - even though I am jumping in here two years late or so, let me add my bit.

As some who have read my PRS-4 review know, I fly balloons, meaning I need to use my watch as the legally required timepiece. For me sturdyness is probably more important than for most civil GA pilots, as the watch (and my person) do get banged around now and then on landing and while working with the generally heavy equipment in often dirty conditions on the ground.
I need a very legible watch, and prefer some way to quickly read elapsed time and or countdown time; a rotating bezel is the most basic way to allow for that, a chrono function with central minute totalizer would be a nice extra (I did fly compettions a lot, and many tasks require second-accurate timing; for general flights, timing minutes is good enough). If that bezel is bidirectional, even better; I can get around with a unidirectional diving bezel, which is OK if I use it to count down to sunset on evening flights (accidentally shifting it means just landing a bit early, which is fail-safe), but is not great when I set it to time flight duration from take-off, particularly to see how long the load in the first fuel tank lasts (which may vary a lot depending on load, ambient temperature, moisture in the air, altitude, and how long the balloon was kept hot-inflated before we actually took off). An accidental shift in that case would give me the impression my fuel consumption is lower than it actually is, which may lead to a faulty decision on whether or not to continue for a certain amount of time - particularly on morning flights, which are essentially limited by the fuel reserve, while evening flights usually take off with much more fuel than needed until sunset. Of course, a bidirectional bezel can be accidentally shifted in both directions, so would not solve the latter problem! It does, however, require a bit more time to set at the moment of take-off, which may result in less accurate timing.

A sturdy chrono with a bidirectional 60-minute or 12-hour bezel and central minute totalizer would be my ideal watch. The 12 hours would help to convert local time to GMT/UTC for filling in the log afterwards (at present, I just note the local times instead of GMT/UTC as it is easier that way; a morning flight is obviously a morning flight in the log, which would not be clear-cut in a location a fair number of timezones distanced if UTC was used). Of course, if the chrono would have a central minutes totalizer, it would leave space on the dial for a GMT/second timezone subdial, so the bezel could be 60-minute...
Finally, date and to a lesser extent day indications are helpful, again to aid in the paperwork (which for me also includes filling out first-flight certificates for the passengers, of course with the date mentioned).
What a good aviator watch certainly does not need is anything that can clutter the dial and impede legibility - such as huge golden 'wings', multiple rows of text telling the wearer how superior the movement is, how deep your crashed aircraft can sink before the watch starts leaking around your then obviously very dead wrist, or what military unit/air force stunt team has endorsed it. Just the brand is OK. And everything needs to be black (or very dark grey) and white, with as much lume as possible.

Clear legibility comes first, followed by fast legibility, old-geezer (reading glasses) legibility and high-stress legibility (as in 'I'm fighting turbulence, is there time to go over that next ridge before official sunset/empty fuel or must I land in the less-than-ideal field coming up below me NOW?').

That it must be reliable is obvious. I have had a quartz go dead on me at an awkward moment, as well as an auto (V7750) watch quitting on me during a flight. Sure, there are areas where a new battery is not readily available, but Western Europe is nog among them; capable watchmakers who can quickly repair a broken mechanical chrono are much more difficult to find in a pinch than a new battery. And with the Ronda lithium-powered quartz movements on some TimeFactors watches, the interval between battery changes is actually longer than the advised interval between watch revisions for a mechanical watch. If mechanical, for me it would have to be handwound.

[docrwm]

This post, along with others, is why I am finding TZ-UK to be one of my favorite places to visit these days! Thanks for a stimulating read.

[abraxas]

...........

A sturdy chrono with a bidirectional 60-minute or 12-hour bezel and central minute totalizer would be my ideal watch. .

(Sorry ... this is the ony picture I could find. If there are any better please direct me to them.)

The forthcoming PRS-17Q chrono with a 12H bezel can be a good canditate for what you are looking. (Even if it means having a couple of spare batteries in the first aid kit.)

Alternately, if you don't want to bother with the batteries ... have a look at some of the new Citizen Eco Drive

If you ask me ... wait for the PRS-17 chrono. It's a classic watch that can also do the job. My feeling is, that with the kind of work that you do, quartz is the only way to really go with.

john

[Fschwep]

The PRS-17 chrono looks like it comes close, indeed. I already asked Eddie if the bezel would be bidirectional, but by then a unidirectional had already been specified. Apparently the battery would last around 2 years if one uses the chrono a lot. Maybe Eddie could include a case back opener and a spare battery as an extra? :wink:
Personally I don't see the use for a 10th-second subdial in a wrist chrono; it's not as if anyone would be able to start and stop such a watch with a margin of error of less than a tenth of a second. I'd love a second timezone subdial instead... :)

[Fschwep]

Oops! Accidentally sent of a post twice. Shouldn't be doing too many things at the same time on my PC. :?

[Crusader]

Many thanks for your comments, Frank !

I have had rewriting/updating the article on my agenda for some time now, but don't really have the time at the moment.

While I agree with your comments about the 1/10th seconds on the PRS-17-Chrono, the sad reality is that one has to make do with what movements are available, and I am happy enough that there is a chronograph with central minute counter available in the first place. :)

Like you, I have come to the conclusion that a bidirectional bezel is sufficient for most purposes (though mine are not in flying, but more mundane walks of life). But there are very few watches with bi-directional bezels around, and much fewer with bi-directional bezels with a solid clicking mechanism as opposed to a mere friction fit.

If the PRS-17-Chrono is successful, I hope that Eddie will consider - at a later stage, obviously - an updated "aviation" version with bi-directional bezel, and a touch wider space between spring bars and case to accomodate thicker straps.

[Fschwep]

Like you, I have come to the conclusion that a bidirectional bezel is sufficient for most purposes (though mine are not in flying, but more mundane walks of life). But there are very few watches with bi-directional bezels around, and much fewer with bi-directional bezels with a solid clicking mechanism as opposed to a mere friction fit.

I have one, actually: a Wenger Pilot Titanium. It's a quartz with a bidirectional ratcheting bezel, very light too, and with a fairly good dial (not black, but grey, which works OK, decent printing as well). It's major faults however are:
- it came with a titanium bracelet that turned out to be mechanically not great (it came undone at the most awkward moments), but also produced nasty black stains on my wrist and any clothing touching it anytime it got a bit warm and moist (how about sweat and balloon burners...). The case and bracelet match, meaning the case has no 'clean' lugs but spaces that look unfinished when another strap is fitted. This was the main reason to get another watch for piloting.
- bad lume, as is none at all on the hands (they are white but they don't light up in the dark, while the numbers on the dial are lumed)
- mineral crystal, so it scratches but can't be polished
- snap-on back, meaning no serious water resistance (maybe this is neccessary as the back is also titanum alloy; I read somewhere that titanium threads can get damaged when they have been fixed for years)
- non-screwdown crown, same as above. But I must admit I have showered with it, and swam a few times (no diving) without ill effects.
Of course it also a standard quartz (no idea what type of movement, but the battery life is about two years or so), meaning it can go belly-up at any moment without warning.
If it had not had the bracelet/stain problem, a better crystal and decent lume I would probably still be wearing it, as it is a comfortable watch to wear due to its light weight, and the bezel is its main advantage (it is even etched AND printed). It replaced my Sinn 256 when that one broke down and gave me cause to lose faith in auto chronos (at least 7750s) for what I do. The Sinn, by the way, also has a bidirectional bezel, but of the friction type; sensible to dirt and the black finish pretty soon came off at the edges where I gripped it.
Once I have a bit more time I'll put up a few pics of the Wenger, scratches and dodgy bracelet and all... So Eddie can get something similar made without the flaws... The Wenger PT is, as far as I can tell, no longer in production.