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Navitimer World - disappointed by the practice tachometer
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Author:  razumny [ Wed Jul 27, 2011 7:00 am ]
Post subject:  Navitimer World - disappointed by the practice tachometer
First off, I am a very lucky man. As previously stated, I got my grail watch, the Navitimer World, from my wife, and I love it!


In the package, there were a number of items, two of which are the instruction booklet for the tachometer, as well as a practice tachometer. I have found this practice tachometer to be very inaccurate, so much so that the practice tachometer is useless for practice purposes.

Am I alone in this experience?
Author:  Sparwood [ Wed Jul 27, 2011 8:31 am ]
Post subject:  Re: Navitimer World - disappointed by the practice tachomete
Can't say that I ever paid much attention to it, nor have I ever had the need to actually use the slide rule.

S
Author:  razumny [ Wed Jul 27, 2011 9:01 am ]
Post subject:  Re: Navitimer World - disappointed by the practice tachomete
Well, I'm making an effort to learn how to work it, as I take no small amount of pride in geeky knowledge and skillsets.
Author:  razumny [ Wed Jul 27, 2011 9:06 am ]
Post subject:  Re: Navitimer World - disappointed by the practice tachomete
The most glaringly obvious error, is when converting between kilometers and miles. When setting the Stat to ten, KM should read 16, but it reads significantly less (can't remember the exact number right now).
Author:  nr123 [ Wed Jul 27, 2011 3:55 pm ]
Post subject:  Re: Navitimer World - disappointed by the practice tachomete
I thought the division and multiplication thing was 'cool' but not practical - if I need to use a slide rule to divide and multiply fairly low numbers I think I have a different issue. Regarding converting km and mi - I have no practical use for it. I have the same watch, just thought it was a nice watch to have.
Author:  Driver8 [ Thu Jul 28, 2011 1:10 am ]
Post subject:  Re: Navitimer World - disappointed by the practice tachomete
nr123 wrote:
I thought the division and multiplication thing was 'cool' but not practical - if I need to use a slide rule to divide and multiply fairly low numbers I think I have a different issue. Regarding converting km and mi - I have no practical use for it. I have the same watch, just thought it was a nice watch to have.

Agreed. I love the historic look of the Navi (and particularly my World), but on a practical level (ther than telling the time, the date and having a handy chronograph, the slide rule is about as useful to me as an abacus. I did make an effort to learn how to use the slide rule when I got my first Navi, but like anything in life, if you don't use it you lose it. My slide rule knowledge has long departed.
Author:  razumny [ Thu Jul 28, 2011 4:05 am ]
Post subject:  Re: Navitimer World - disappointed by the practice tachomete
Driver8 wrote:
nr123 wrote:
I thought the division and multiplication thing was 'cool' but not practical - if I need to use a slide rule to divide and multiply fairly low numbers I think I have a different issue. Regarding converting km and mi - I have no practical use for it. I have the same watch, just thought it was a nice watch to have.

Agreed. I love the historic look of the Navi (and particularly my World), but on a practical level (ther than telling the time, the date and having a handy chronograph, the slide rule is about as useful to me as an abacus. I did make an effort to learn how to use the slide rule when I got my first Navi, but like anything in life, if you don't use it you lose it. My slide rule knowledge has long departed.

Let me first specify what I'm referring to, as it looks like you guys are misunderstanding me. With the watch, among many other documents, was a piece of cardboard with two round pieces of cardboard attached to it, with pretty much the same markings as the tachometer on the watch.

I am actually getting a fair amount of use out of it, and the tachometer on the watch itself is as accurate as can be. However, the practice tachometer has two problems. First, the outer and inner rings are not calibrated right, and some of the markings are different than those on my watch.

Both issues make the practice tachometer useless as a learning tool, and I am surprised that a high end brand like Breitling would let something like that slide.
Author:  Roffensian [ Thu Jul 28, 2011 4:37 am ]
Post subject:  Re: Navitimer World - disappointed by the practice tachomete
razumny wrote:
Driver8 wrote:
nr123 wrote:
I thought the division and multiplication thing was 'cool' but not practical - if I need to use a slide rule to divide and multiply fairly low numbers I think I have a different issue. Regarding converting km and mi - I have no practical use for it. I have the same watch, just thought it was a nice watch to have.

Agreed. I love the historic look of the Navi (and particularly my World), but on a practical level (ther than telling the time, the date and having a handy chronograph, the slide rule is about as useful to me as an abacus. I did make an effort to learn how to use the slide rule when I got my first Navi, but like anything in life, if you don't use it you lose it. My slide rule knowledge has long departed.

Let me first specify what I'm referring to, as it looks like you guys are misunderstanding me. With the watch, among many other documents, was a piece of cardboard with two round pieces of cardboard attached to it, with pretty much the same markings as the tachometer on the watch.

I am actually getting a fair amount of use out of it, and the tachometer on the watch itself is as accurate as can be. However, the practice tachometer has two problems. First, the outer and inner rings are not calibrated right, and some of the markings are different than those on my watch.

Both issues make the practice tachometer useless as a learning tool, and I am surprised that a high end brand like Breitling would let something like that slide.



We understand - although it's not a tachometer, it's a slide rule.

The vast majority of people just don't think that it's important on the watch itself, let alone the piece of cardboard. My guess is that 99% of the practice ones go back in the box where they stay.
Author:  Roosterboy [ Thu Jul 28, 2011 6:12 am ]
Post subject:  Re: Navitimer World - disappointed by the practice tachomete
The Navitimer line was developed for aircrew (pilots, navigators etc). The watch is extremely accurate in time keeping and also as a functioning flight computer. The use of the circular slide rule ("tachymeter") takes some getting used to. Likely the practice/demonstration one you received is poorly constructed.

The circular slide rule works quite well for all it was intended to do. Practice is the key and an understanding of what you use this information for would also help. Funny mine is used pre-flight only. I switch on dressing to a timex on velcro that can be placed in different places throughout the aircraft.

The World is a well thought out excellent working watch. If you bought it for the looks enjoy becuase it is a wonderful watch that always sparks a conversation with anyone who sees it for the first time.

:cheer: :cheer:
Author:  Acro-Pilot [ Thu Jul 28, 2011 8:35 pm ]
Post subject:  Re: Navitimer World - disappointed by the practice tachomete
Razumny -

I just bought the same watch about a month ago and found the paper "wiz wheel", as we called it in flight school, to be calibrated and aligned. I would check back with your AD and ask them if they might be able to have Breitling send you a new one. If they won't and you're serious about it, they seem to come up on eBay once a month or so.

It's great that you're learning to use it! ...it's a good life skill.

Keep in mind while your using the circular slide rule on your Navitimer that when we were required to do groundspeed and fuel endurance calculations with an actual circular slide rule in flight training, it was the size of a bread plate. The circular slide rule on the Navitimer is functional but would take bionic eyes to use with any degree of precision.

- Peter

PS - By the way for all of you thinking I'm 104 years old because my flight training required a wiz wheel, it was still a requirement in 1994. I'm 42... :wink:
Author:  sharkman [ Thu Jul 28, 2011 9:53 pm ]
Post subject:  Re: Navitimer World - disappointed by the practice tachomete
All Navitimers with bi-directional bezels have the same paper practice wheel. Also some watches in the Professional line like the Skyracer. Perhaps there was a strange print error on yours or maybe it's just a learning curve.

But it's not a tachymeter as a some keep saying. As Roff already said, it's a slide rule. A tachymeter is a fixed scale - usually on the rehaut area, but often on the bezel itself used to compute a speed based on travel time or measure distance based on speed. Elapsed time or known speed is compared to the fixed scale. A tachymeter scale is very common on chronograph watches.

The Navi slide rule has many functions. But a tachymeter scale only converts at a glance the number of seconds it takes for an event to happen and the number of times that event will occur in one hour. It's based on a simple algebraic equation with one unknown variable and a known constant of 3600 (seconds/hour).

I can use a tachymeter scale if I think hard enough to make my head hurt. Using the circular slide rules on my Navi and Skyracer would make my head explode. And I took algebra and geometry X years between the abacus and the first Texas Instrument hand calculator.

Now solve for X, take two aspirin, and enjoy that amazing watch in the morning. :poke:
Author:  onewatchnut [ Tue Aug 02, 2011 8:52 am ]
Post subject:  Re: Navitimer World - disappointed by the practice tachomete
razumny wrote:
The most glaringly obvious error, is when converting between kilometers and miles. When setting the Stat to ten, KM should read 16, but it reads significantly less (can't remember the exact number right now).

10k is 6.2 miles, not 16. :poke:
Acro-Pilot wrote:
PS - By the way for all of you thinking I'm 104 years old because my flight training required a wiz wheel, it was still a requirement in 1994. I'm 42... :wink:

I still have one in my flight bag, and I'm a lot older than you. It does things the Navi slide rule will not. Density altitude, for example.
Author:  razumny [ Tue Aug 02, 2011 10:54 pm ]
Post subject:  Re: Navitimer World - disappointed by the practice tachomete
onewatchnut wrote:
razumny wrote:
The most glaringly obvious error, is when converting between kilometers and miles. When setting the Stat to ten, KM should read 16, but it reads significantly less (can't remember the exact number right now).

10k is 6.2 miles, not 16. :poke:
Sure, but one mile is 1.6 kilometers. When setting the distance in miles at Stat, you can read the distance in kilometers at the KM mark at 12 o'clock on the watch face...
Author:  onewatchnut [ Wed Aug 03, 2011 4:33 am ]
Post subject:  Re: Navitimer World - disappointed by the practice tachomete
You are correct, 10 miles is 16 km. :oops: I thought you were going from km to miles.

My Navi Olympus displays correctly. 10 on the bezel set at STAT (Statute miles) displays 16 at the KM (kiloMeters) index on the dial. Conversely, 10 at the KM index displays 62 at the STAT index. It is correct both ways. What does yours display?

I never looked at the paper teaching tool, so I can't comment on it. Go to http://sportys.com/source/images/7205.pdf and download the E6B instruction book. It will teach you all you need to know about the slide rule on the Navi. When you're finished, let us know how you did attempting to focus on the tiny numbers on the slide and dial. That's one more reason I carry an E6B in my flight bag.
Author:  razumny [ Wed Aug 03, 2011 4:47 am ]
Post subject:  Re: Navitimer World - disappointed by the practice tachomete
onewatchnut wrote:
You are correct, 10 miles is 16 km. :oops: I thought you were going from km to miles.
No worries, mate

onewatchnut wrote:
My Navi Olympus displays correctly. 10 on the bezel set at STAT (Statute miles) displays 16 at the KM (kiloMeters) index on the dial. Conversely, 10 at the KM index displays 62 at the STAT index. It is correct both ways. What does yours display?
My watch displays it correctly all the way, it's only the teaching tool

onewatchnut wrote:
I never looked at the paper teaching tool, so I can't comment on it. Go to http://sportys.com/source/images/7205.pdf and download the E6B instruction book. It will teach you all you need to know about the slide rule on the Navi. When you're finished, let us know how you did attempting to focus on the tiny numbers on the slide and dial. That's one more reason I carry an E6B in my flight bag.
Hunh, grabbing an E6B might not be a bad idea. I'm thinking of qualifying for a PPL anyway, so I suppose I'd need it sooner or later.

I am doing fine with the numbers on the slide and dial. My glasses work beautifully...
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