If you accept as a principle of R/T the desirability of getting the maximum amount of information over in the minimum amout of air time, you will see how moronic the use of 'hectopascals' is.

SPIKE MILLIGAN
 

The following (paraphrased) excerpt from an old interview with Spike Milligan - I think it was with Harry Secombe and Terry Wogan in 1987 - seems relevant to this discussion.

SM: My father had piles.
TW: You mean hemorrhoids?
SM: No he had them before they went metric.

MJG
Who was responsible for issuing the notice of change from millibars to hectopascals to the RAAF in 1987.

GMT was fine in an age when clocks weren't too accurate. It was handy to know how many seconds there were going to be in a given calendar year even if no one knew exactly how long each second was because this could only be determined retrospectively via astronomical observation.

Now that we live in the age of very accurate atomic clocks it is more useful to have seconds of a standard length and then add a leap second every now and then to keep UTC within a second of the 'mean time' UT1. UT1 is the modern equivalent of GMT, determined by astronomical observation.

Like I said at #3, the CAA are considering using an abbreviation.

Back at post 33 RAT 5 said
So why do we measure:

speed = knots,
route distance = nautical miles.
altitude = feet
visibility = metres
wind = knots.

When I was learning the penny dropped when I realised that if I heard "feet" that was up or down and when I heard "metre" or "nautical miles" that was in front or behind. i.e to differentiate between vertical or horizontal distance.

When I was learning the penny dropped when I realised that if I heard "feet" that was up or down and when I heard "metre" or "nautical miles" that was in front or behind. i.e to differentiate between vertical or horizontal distance.

That's an interesting theory, and very personal. I'm not advocating anything as I was so used to the current units; but it no longer matters, professionally. If west EU measures visibility & runways in meters, and metrication has become the European norm outside UK veggie markets, and east EU uses meters for altitude & wind speed, and I've flown French GA a/c with kph ASI's, it would be possible to go fully metric in EU if range was also quoted as km's. However, the might of EU, west & east including Russia, would lose out to the power & influence of USA, China, Japan and southern hemisphere, and the status quo will remain. So metrication in our industry, is a part-time affair and at the end of the day it's only numbers.
Hap became possible because it was at no cost to instrument manufacturers. The same with changing Kelvin to Celsius. There is the battle between Watts & Joules, that may still be on going. Not good for anglo-french relations. Fortunately Newton holds sway in one field.
And who gives a peck or a bushel about it all anyway. 'Chain' them up in the 'yard' next to the horse with 14 'hands' and a 'cubit' of mane, drinking a pint and telling the rest of the world to go forth & multiply.
Happy New year, EU version, but at differing times.

What "battle" is that ?

The two have different dimensions, so you can't substitute one for the other.

Good old Mr Celsius had a unit named after him :)


edited to add: Sorry, I just read the first page of the thread, not realising there were another two pages !

Watts to joules calculation
The energy E in joules (J) is equal to the power P in watts (W), times the time period t in seconds (s):
E(J) = P(W) × t(s)

Sorry Dave; I was forgetting about the 'time' parameter. I'd been confused when they'd tried to metricate bhp. I should have stayed awake and the back of class.

Sadly, I too can remember doing power calculations in hp.

In fact I recall having the hp/kW conversion ratio marked on my slide rule. :O

chevvron,

I received your PM but I’m unable to reply via PM or your email address (on PPRuNe).

Please email me at the address I previously sent you.

I'm still unable to access PMs. Been off again for a couple of days but posted the minimum 5 postings so at least I'm partially back on line.

Straight out of my head.

746 Watts = 1 Horse Power.

It could have been much worse. Imagine if the early research on pressure had been carried out not by Pascal, but by by Mendeleev, Gay Lussac, or Avagadro? :E

'hectoBoyles' even?