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-   -   Knots are for boats! (https://www.pprune.org/tech-log/490129-knots-boats.html)

Calmcavok 10th July 2012 09:46

Why not measure in multiples of "Wales"? You often hear people/media describing places relative to the size of Wales (I recall Australian farms often being described as x times the size of Wales).

Your common or garden jet would travel approx 3 Wales/hr, a turboprop would be about 2 Wales/hr. Height could be measured in fractions of Wales's.

Just a thought.

stilton 10th July 2012 11:01

I vote for Warp Factor..

InSoMnIaC 10th July 2012 11:05


I vote for Warp Factor..
Lets break the sound barrier first then we can talk about warp factor

AdamFrisch 10th July 2012 17:43

I grew up in metric, but obviously comfortably use feet and knots in my flying. However, you often hear in t he UK and the US "I can't think in metres" and how they can't gage it. Exactly the same problem I have in feet - I can't gage a distance in it without first doing the conversion from meters.

But there's a simple solution for you guys and everyone could use meters tomorrow in the old "Farenheit"-belt of the world; Because you can all use yards, right? A yard is a meter!

yotty 10th July 2012 17:50

Not too sure that a yard equals a meter. Could we settle on fathoms? ;)

FlightPathOBN 10th July 2012 17:59

I would like to see them dump the mag compass headings and magvar...

with grid north and GPS, the whole mag nomenclature for runways is a real pain, especially when it switches, and they re-name the runways....

Uncle Fred 10th July 2012 18:00

Prefer knots for flying. Although grew up with feet/inches/yards, the metric system is just fine--base ten arithmetic works every time!

Don't mind visibility in metric but I do prefer the FLs the way they are (in other words not in meters). For me it is just simpler to use. Always a bit of a thinking exercise when flying into or through China's airspace. Much easier now going through Russia's and I might be wrong about this, but it seems the controllers like it as well.

daved123 10th July 2012 20:06

Metric system
 
Uncle Fred, I am sure you must have seen it in Vendee also, the French, in the home of the metric system, have invented a new non-metric system of distance measurement - The Minute !
All over we see direction signs to McD, Intermarché, Leclerc etc "au feu a droite, 2mn" (at the traffic signal, turn right, 2minutes) although if anybody tried to achieve those timings they would suspect that, being patriotic, they must have asked Air France to calculate the 'distance'
daved

parabellum 10th July 2012 20:16



RVR 300' ( 91 m ) wow that's way below CAT3B territory and I think you'd be
told "RVR 300 feet". Couldn't even takeoff with 300' RVR
Think you may be a bit confused there Nitpicker, CAT3B can be zero/zero in terms of viz and cloud base for both landing and take off, depends on the capability of the aircraft/state of airport aids/crew recency etc. as well as your own airlines SOPs. Been a while since I did one but I seem to remember 75meters and 20' as the landing minima for the B747-400 that I flew and that had more to do with taxying than landing.

Herod 10th July 2012 20:19

Flew an aircraft many years ago where we uplifted fuel in litres, calculated it in kg, the main tanks were gauged in Imp gal, and the aux tanks in USG. My brain hurt. Having then flown for many years using runway lenth in metres, I moved to a company which used manuals direct from Boeing (this in the UK) and I had to start thinking in feet. Counterintuitive.

Piltdown Man 10th July 2012 20:33

Seconds, minutes, feet in nautical miles (ish), degrees of latitude - can I stick with knots please?

boguing 10th July 2012 20:35

On a septic web forum a few years ago a native pointed out that the handy 345 triangle trick wouldn't work in metric. He went quiet when I pointed out that it would work with Cornflake packets.

GOLF_BRAVO_ZULU 10th July 2012 21:25

Isn't the whole point of a 345 triangle that it is devoid of the need for specific units of linear measurement? They could be in Millimeters or Cables (tenth of a nm) and still give the correct ratios for Mr Pythagoras's wonderful triangle.

Just wait until some brown job artillery wallah comes along and tries to convince you that Mils are better than Deg, Min, Sec of arc. You will then get the tedious explanation about a Metre being one ten-millionth of the meridion that passes through somewhere called Paris and how easy it is to pace it out on an OS map or NATO JOG chart. He (or possibly she these days) should be told that metres are too bloody small for anything horizontal and too big for anything vertical.

boguing 10th July 2012 21:33

Yep.

Fun can still be had though. Surveyor friend asked me to help him lay out a site. Field into 'plots'. And although a more than successful yachtsman and navigator, it became apparent that 345 didn't feature in his knowledge.

Sent him off with the tape reel and giving him different multiples of 3,4 and 5 on each occasion that we had to establish a right angle. Wish I'd videoed it. The more that I hysterically giggled, the larger the multiple had to be so that he couldn't hear me.

I've never actually confessed to it...

Until now. Colin.

Uncle Fred 11th July 2012 01:59


Uncle Fred, I am sure you must have seen it in Vendee also, the French, in the home of the metric system, have invented a new non-metric system of distance measurement - The Minute !
All over we see direction signs to McD, Intermarché, Leclerc etc "au feu a droite, 2mn" (at the traffic signal, turn right, 2minutes) although if anybody tried to achieve those timings they would suspect that, being patriotic, they must have asked Air France to calculate the 'distance'
daved


Ah yes, the French minute--un peu de temps! Fungible, with plasticity, without fixed interval...it has a character of its own but does add a element of relaxation to the proceedings.

Reminds me of the quote from Gustav Flaubert Une minute--On ne se doute pas comme c'est long, une minute

reynoldsno1 11th July 2012 23:02

I believe, in principle at least, that the Chinese are going to use feet for altitude at some unspecified date in the future. Same goes for WGS84 co-ordinates.

stilton 12th July 2012 09:11

'Lets break the sound barrier first then we can talk about warp factor'


That was done a few years ago actually :confused:

Capot 12th July 2012 09:53

As a Gunner (RA) I was around when we changed in the early 1960s from yards (NOT equal to a metre!) and degrees, to metres and mils (6,400 in a circle, vs 360X60X60 seconds). The simplicity of the shell-lobbing arithmetic from that moment was wonderful.

Metres have a scientific basis as a measurement constant and navigation tool, just as knots do. Statute miles, yards, feet and inches are something to do with how Roman soldiers would yomp along and other measures that meant something 2,000 years ago, and they belong in that time.

I navigate my boat in knots/nautical miles, because I locate myself using latitude and longitude, and so does my GPS when it's not on some national grid or another. My aircraft, when I owned one, measured speed in knots so I navigated in nautical miles. If I'm using a map on land I navigate in metres/kilometres/kph because, in the UK and most other countries I plod around in, the grid and vertical measurements on the map are metric. And thank God for that.

nitpicker330 12th July 2012 10:14

Parabellum:-- nope no confusion mate. CAT 3B at KJFK still requires at least 600' RVR to "commence the approach" you cannot commence any approach on the planet in zero zero.!!

Any approach below 1000' can be continued to minima for a look see if the RVR falls below minima. CAT 3B on the other hand can continue to land as visual ref is not needed until after nose wheel touchdown.

Although you'd be pretty brave to land in zero zero CAT 3B...


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