Lbs and Inches V. Kg and Meters?

[disctilt]

I have recently started learning to fly helis and picked up a book I bought a few years ago (published 1997) and was taken aback to find calculations of moments measured in Foot/Pounds.

I was wondering if the units of measurements in the industry is still dominated by the imperial system? Do ATC still call heights in feet? Are the JAA exams in imperial or metric?

I hope I can learn/do the exams in Meters and Kilograms... none of my schooling was in the "old system" :) - its almost like speaking a different language.

[Gaseous]

American manufacturer use their own peculiar brand of imperial measurements for pretty much everything. volumes pressures torques etc etc. When you've been flying for a bit the conversions become second nature and its not really a problem. If you want metric, fly european. Even then the aviation industry is littered with inconsistancies. ATC depends where in the world you are. When I did my JAR exams they were littered with inconsistancies. You gotta learn to live with it.

[Stringfellow Dork]

Prepare yourself to have to learn 'em all!

[What Limits]

On the Islander Aircraft I used to fly we had a mixture of cockpit indications including

Torque - foot/pounds
Fuel quantity - US Gallons
Fuel Flow - pounds per hour
TGT - degrees C
N1 - percent
pressure - bars and psi

As the man said - learn 'em all!

[belly tank]

From experience my missus prefers to use inches as the standard form of measurement!!!:ok:

[SASless]

Mine prefers pounds.....

[Genghis the Engineer]

To quote the great (but thankfully not yet late) Dr. Darrol Stinton...

Be ambidextrous in your units.

You'll meet many and various unitary systems around flying machines (or engineering in general), nobody is going to have any sympathy for you if you don't know them. The only thing to do is roll your sleeves up and learn 'em - whatever you grew up with.

Like you I grew up in SI units, but regularly fly in Imperial. On the other hand I gave a lecture at Embry Riddle (an American aeronautical university) earlier this year and did the whole thing in SI - you should have seen the students panic, they'd never seen a Pascal before !

G

Who has been known to do aircraft weight and balance in kgf. inches :} In the meantime I own one aircraft where everything on the engine is in metric, and on the airframe in imperial.

[PoorPongo]

An example only to add weight to the 'know both' theme:

I moved from flying Lynx to (UK) Apache. The Lynx was a Westlands frame designed in metric with Rolls-Royce engines in imperial. The Apache, on the other hand is an entirely imperial airframe design with newer Rolls Royce engines in... you guessed it -metric!

I too was entirely educated in SI units. You just get used to it; the ability to do mental arithmentic is a pretty fundamental pilot skill anyway!

PP

[SASless]

Just think if we were being paid in the old currency....Shillings, and such? That would add yet another layer of confusion to this.

But more importantly....is my "dram" an Ounce, a Gill, or some awkward EU measure now? Actually...I prefer quarts when applied to that lovely Scottish nectar.:E

[cl12pv2s]

Hello,

Q. Who else apart from the Americans still use imperial units?

A. Myanmar and Liberia Source (http://lamar.colostate.edu/~hillger/internat.htm)

What if someone suggested (as I am now) that it is only out of stubborness and / or laziness that the Americans still use imperial units?

Afterall, the metric system is undoubtably more superior and efficient.

The amount of money it must cost various industries producing products with both systems...the amount of time it must take in schools teaching it...etc..etc.. Wasn't the Mars Rover demise a result of a Imperial / metric blunder?....I know of a story of a jet airliner that came a cropper to a similar lbs / kgs error.

While everyone who has replied in this thread so far has said,"Live with it!" I'm going to stick my neck out and say...

"When are the Americans (and world consumers) going to call for change? It makes no sense at all."

OK, so yes, as a pilot in today's day and age, I have to live with it. However, if people don't start putting pressure the folk who make the 'Imperial or Metric' decisions (i.e manufacturers, congress etc...) the farce (mixed systems) will continue.

At the end of the day, imperial units are all referenced from SI units anyway. Why bother with the extra step?

That's all.

cl12pv2s

[Aussie Mate]

Hey Belly.

Yes, but she couldn't quite grasp the concept of fractions of one inch.

[belly tank]

Aussie mate,

good comeback i like it!...cheers!

[Head Turner]

Yes, the Americans are stubbon and 'never listen to anything that is not American' so don't expect them to change to a system which is obviously better. The metric system is a far more useable and produces less errors that the American system.

I deal alot with the USA and their system is awfull but they won't change so get use to it. They are arogant and have a huge industy so why should thet change?

[Billywizz]

Bellytank

surely you mean inches per second, its what you do with it that counts!

[Genghis the Engineer]

Afterall, the metric system is undoubtably more superior and efficient.

Oh were it so simple.

The fact is that foot-pound-second is a perfectly rational system of units that works just as well and consistently as kg-m-s.

The world is effectively divided into two - those using the old Imperial system, and those using SI, whilst in reality both use lots of bastardised units like kgf or cm that confuse the issue. Personally I think that everybody should learn both.

The arrogance of Americans thinking they don't need to learn SI, and Europeans who think that Imperial is obsolete and can be ignored does nobody any good. Just be thankful that for the first time in human history there are only two major systems to learn - 200 years ago every country had it's own, often every town or every factory.

G

[Letsby Avenue]

Arrogance...! We gave them imperial measurments, their whole industry (which is pretty big) runs in imperial. Why on earth would they want to give that up because the europeans adopted some re-jigged french/german system? Even us brits don't enter into the spirit wholeheartedly - who for example works out their car petrol consumption in Ltrs/100 km ?

[ShyTorque]

Apart from refuelling conversions from pounds / litres / gallons / US gallons (obviously vital to get correct), from a piloting point of view just call all units "bananas", as they may as well be.

;)

Having said that, in UK I ride a motorcycle that has kph rather than mph on the speedometer but I know the conversion figures to avoid the dreaded camera flash.

[belly tank]

Billywizz wrote

"Bellytank

surely you mean inches per second, its what you do with it that counts!"

your correct BILLY!!..i can't figure out what to do between 8-10 inches!!...there is some real torque effect happening between that range!!!...and the fuel consumption really goes through the roof!!........

getting back to the subject.....yes i do use all units...( of my brain) to work calculations..as you all do as well....LB...KG...LITRES...GALLONS...INCHES...%...I should have been a mathematician...then again i would have made too much money doing that job!!!.....:}

[SASless]

head turner....Arrogant ? The Americans....I would suggest you give us too much credit....after all one cannot expect much out of a race of people that tried to make salt-water tea.:p

But then I drive my American made pickup truck...do mechanical things with my American made tools on American made products...and thus I have no problem dealing in American units....until I work on my Kubota farm tractor...then I buy American made metric tools and buy American made parts (filters...etc...) being Japanese made....it has not needed any parts yet.

Thus, I fail to see the big deal....all my torque wrenches are marked in American units...as are my tech manuals thus no conversions needed.

But then.....being the big boy on the block when it comes to building things....I guess we can get away with it. That is not being arrogant....just realistic.

[Nail The Dream]

... this could all explain why, ( in a non-aviation industry ) as an apprenctice many years ago, I was asked to go the the stores for a 12 inch metric ruler, a left handed screwdriver, and a sack of 2 ounce sparks for the grinding machine.....

The storekeeper was obviously ex RAF 'cos he knew exactly what I wanted and sent me back with them all :uhoh:

[Dave_Jackson]

SASless,But then.....being the big boy on the block when it comes to building things....I guess we can get away with it. That is not being arrogant....just realistic But what about big mistakes, like not making the conversion when grinding the mirror on the Hubbell telescope? ;)

Dave

[SASless]

Dave....show me a perfect system that eliminates human error...just one. The British had the Titantic....watertight compartments that did not have bulkheads clear to the overhead thus water could spill over the top into the adjoining compartment. NASA and the Shuttle....lots of problems there....auto makers recall cars....airplanes and helicopters have AD's issued....God made the pit in the Avocado too big....it just is not a perfect world.

[Wunper]

I think the US Gallon is a clever unit

at 15C ~ 60F

1 USG Avgas weighs~ 6Lb

1 USG Avtur weighs~ 7Lb

Makes it easier for my zums:)

[MightyGem]

I think the US Gallon is a clever unit
Yes, but why, when Americans usually make things bigger, did they make it smaller??:)

[SASless]

Plain and simple....we sell less for the same price that way....or am I getting confused again?;)

[Two's in]

MG

During one of those very long evenings watching a bunch of hicks turn left (or NASCAR as everyone else knows it) the penny dropped that the US Gallon is based on 16 FL OZ to the Pint instead of 20 FL OZ, just like the Brits insist on 16 Dry OZ to the pound, hence the 25% overmeasure, or under, depending on your origin. Seems perfectly logical when you look at it like that.

They did inherit Imperial from the Brits, but they have just decided to stick with this particular habit. Mind you, a bloke finishing his pint, sticking a couple of gallons of petrol in the car and driving a few miles home to eat half a pound of bacon in a sarnie, and then complaining about the US fixation with Imperial units seems a touch ironic.

The ultimate gotcha has to be the Canadian early 767 some years ago that loaded Kg's, failed to display Lb's, dipped the tanks in inches, fudged the conversion and eventually became a really big glider. They all walked away, but I bet the crew had a sharper appreciation about standard units of measure after that.