Do Americans use metric system?

[mikewint]

1 bar does not equal 1 atmosphere. 1 atmosphere is, in fact, 1.01325 bar.

Entirely and completely correct, I was speaking in generalities which is a bad thing, Es tut mir leid. the BAR at 100,000 Pa is NOT an accepted SI unit nor is it on the "accepted for use" non-SI units like the common units: Days (d); Minutes (min); Hours (h); the common angle units of Degrees, Minutes of Arc; and Seconds of Arc; for land the Hectare; the original metric Liter/Litre; and the metric Tonne. The SI does however say that while not "accepted" it is OK to use. As a result we hear/see a mix of hectoPascals, kiloPascals; and Bars except for the common weather guys who still report in atmospheric pressure in INCHES leaving out the "OF WHAT" part and many cases even the inches.

mm for length units and N for force units

That mixture of units gives you two separate length measurements m and mm^2 in the numerator and denominator respectively. The reason it works and comes out in M (Mega - million) is because 1 meter = 1000 mm and 1 m^2 is 1000mm x 1000mm = 1,000,000 mm^2. For calculations to remain valid with answers in the correct units you need to stay within a particular system, in this case, the MKS system or Meter-Kilogram-Second system of units.

 

[mikewint]

Lucas electrics,

Ah yes how well I remember LUCAS, Lord of the Dark

 

[mikewint]

Alan Turing made a compelling argument that humans should adopt base 12 number system

If you really stop and consider it the recurring nature of 12 is really astounding: A ruler has 12 subdivisions. The Romans also divided the foot into 12 divisions and the UNCIA was 1/12th of a Roman pound.. Produce like eggs. donuts, flowers, golf balls, beer, soft drinks ( a case is 24 cans), etc. are sold in dozens and grosses , pharmacists, jewelers, reloaders use the 12 ounce Troy pound as did the British Mint: 1 shillings = 12 pence and 20 shillings = 240 pence or 1 pound sterling. Consider our timing and dating system there are 12 months in the year, and our day is measured in 2 sets of 12 hours. The Babylonians had a 12 hour day. In geometry, a complete circle at 360 degrees is really just subsets of 12, i.e. a 360 degree circle consists of 30 sets of 12. The 12 signs of the zodiac. There were 12 apostles in the bible. You have four fingers with three joints each or a total of 12 joints
Think about the way we name our numbers. We have separate names for 11 Eleven and 12 Twelve then 13 Thirteen. So what happened to 11 -oneteen and 12-twoteen. The Germans did the same 11 - elf and 12 - zwolf while 13-is dreizehn or three and ten. Clearly, it was natural across many cultures to think in terms of dozens.
Now for those of us steeped in decimal calculations base 12 presents some real challenges. Starting with inventing two new digits and naming them. A number of proposals have been put forth such as an upside down 2 and 3. Or A=10 and B=11; X=10 and E=11; T=10 and E=11; or the keyboard friendly *=10 and #=11. Take your pick. As for names DEK, EL, and Doh are gaining in acceptance.
Base 12ers point out that decimal fractions like 1/3 = 0.3333333 repeating in decimal, in base-12 it comes out even at 0.4 but then 1/5 even in decimal at 0.2 in base-12 becomes 0.2497 repeating. So no real gain there.
Multiplication requires some thought 2 X 6 = 10 (1 dozen and zero); 3 X 7 = 19 (1 dozen and 9); or strange to see A X B or T X E or * X # [10 X 11] = 92 (9 dozen and 2).
Kids would probably have no more problems than with decimals but us old farts, that's another story

 

[Barrett]

Then there was the Imperial Japanese Navy which measured distance and altitude in meters and airspeed in knots!

 

[dogsbody]

Here in Canada, we have an extra confusion point. There is the original Imperial measurement system that was used up to the late 70's when we went metric, after the US proposed the change, but then they didn't. Then there is the US system that is an off-shoot of the Imperial system but with differences. As our major trading partner, almost everything is marked with both systems: grams/ounces ( but not Imperial ounces ); litres/gallons ( again, not Imperial gallons ).

Ain't life a female dog!


Chris

 

[MiTasol]

And a meter is a mental device used for measuring a linear distance.
And speaking of the confusion of tools needed to work on today's "global" machinery, I remember maintaining a fleet of Netherlands manufactured Fokker F27s of varying vintages with RR Dart engines made from 1947 to 1977, with Dowty props of varying ages, Lucas electrics, Maxaret antiskid, and Goodyear and Dunlop brake assemblies. SAE and metric tools weren't enough. You had to have British Standard and Whitworth as well. Sometimes you would get an older Dart with newer accessories on it and you'd wind up using Whit, BS, and metric all on the same job. Newer combustion cans on an older engine might have "updated" hardware installed...or not.
Cheers,
Wes

My training instructor in 1962 said his job was to teach us the three ways to design and build aircraft.
The RIGHT way,
The WRONG way, and
The BRITISH way.

The F-27 was a British aircraft assembled in Holland.

 

[MiTasol]

Here in Canada, we have an extra confusion point. There is the original Imperial measurement system that was used up to the late 70's when we went metric, after the US proposed the change, but then they didn't. Then there is the US system that is an off-shoot of the Imperial system but with differences. As our major trading partner, almost everything is marked with both systems: grams/ounces ( but not Imperial ounces ); litres/gallons ( again, not Imperial gallons ).

Ain't life a female dog!

Chris

Politicians and Public Servants (an even bigger contradiction in terms than Military Intelligence) do not give a manure about whether something works in real life.

 

[XBe02Drvr]

The F-27 was a British aircraft assembled in Holland.

BZZZZT! WRONG!
Designed by Fokker with financial aid from the Netherlands government, built by Fokker, it was British only to the extent of using Dart engines, Dowty props, Lucas electrics, Rootes cabin blowers, and Dunlop wheels and brakes. That was because in postwar Europe, indigenous options were limited and US equipment was overly expensive, not inherently superior, and full of unfamiliar design features and weird dimensions and hardware. The F27 was conceived to be the worldwide DC3 replacement without being "yankee-centric". It actually succeeded rather well despite its higher landing speeds and lack of reverse thrust capability. Way better than its "improved" American cousin, the FH227, of which a third of those manufactured have crashed fatally over the years.
Cheers,
Wes

PS: When our local airline switched from DC3s to FH227s, there was a spate of runway overrun incidents on our downsloping 4800 ft runway, especially in winter. After repeatedly deplaning passengers into a snowbank and hiking them from the end of the runway to the terminal in the cold and snow, then shoveling the airplane out, they started overflying our stop at the slightest excuse. Eventually they more or less got everybody trained to drive 50 miles to the larger airport up the road. We became an EAS airport, and eventually airline service ceased altogether, with my (eventual airline pilot) friend, Kathleen being the final station manager and closing it down.

 

[MiTasol]

BZZZZT! WRONG!
Designed by Fokker with financial aid from the Netherlands government, built by Fokker, it was British only to the extent of using Dart engines, Dowty props, Lucas electrics, Rootes cabin blowers, and Dunlop wheels and brakes.

And a lot of other British parts - Dowty landing gears, Redux bonding, Smiths Instruments, British cable tensioners, Brit fuel system components, choke heating, Brit oxgen and plumbing, pneumatics instead of hydraulics, etc, and at some operators even Brit radios. And don't forget the bicycle chains that the Brits love so much.

A not uncommon joke here in Aus was that it was a Brit aircraft and that Fokker only designed and built the box it came in.

The F-28 was also full of Brit stuff but infinitely nicer to work on. It also had a lot of Lockheed features in it. The windscreen attachment and those horrible screws with what looked like a Dzus slot in them (I cannot, and do not want to, remember the proper name for them) were almost perfect copies of L-188 Electra design features to name just two items.

Incidently, according to Donald Douglas the following aircraft were all DC-3 replacements - DC-4, DC-5, DC-6, etc.

 

[XBe02Drvr]

And a lot of other British parts - Dowty landing gears, Redux bonding, Smiths Instruments, British cable tensioners, Brit fuel system components, choke heating, Brit oxgen and plumbing, pneumatics instead of hydraulics, etc, and at some operators even Brit radios. And don't forget the bicycle chains that the Brits love so much.

I know, I worked with most of that stuff. We had for awhile a very early (1957) one that was still in BEA color scheme and was Brit all the away, even to the COM/NAV radios which we had to rip out because they wouldn't tune the .025 and .075 frequencies. The right engine on that one had a 3 digit serial number with a 1947 manufacture date, a carton full of logbooks, 80,000+ hours of flight time, and 11 different data plates from various Mk numbers that the engine had been modified to over its lifetime. It had been mounted on six different aircraft of five types in that time.
The factory techs that came over to supervise our D checks and the wing bolt service bulletin were very dismissive of American aviation practices in general and our maintenance department in particular. They said that Fokker refused, with good reason, to certify any facilities outside the "civilized world" (Europe and Japan) to do any of the critical work such as wing bolts or D checks, so they did a lot of traveling. According to their leader, a grey haired chap with an ageless face who had been with Fokker since the thirties, when the F27 project began in war-torn Europe, the only options for aircraft appliances were British and American, a no-brainer decision, as British stuff was less expensive, technically superior, and much more familiar worldwide.
Cheers,
Wes

 

[Elmas]

A Friend of mine made, mid '60s, the last course in piston fighters.
They started the flying school, he told me, with Piaggio's, whose instruments were metric.
Then with T-6, whose instruments were Imperial.
Then with Fiat G-59, whose instrument were metric again
and finally with P-51, whose instruments were Imperial...
Really a mess, He told me, so they painted red stripes everywhere indicating dangerous limits...

 

[MiTasol]

Just for interest here is the ICAO standard for measurements in aviation - I have not attached the later revision pages.
For Altitude I would say only about 50% of countries comply
Interestingly, on the last page is the ICAO standard for dates. Look in the lower corners of each page and you will see ICAO did not, and still does not, comply with their own ruling.

 

[Ole Bill]

We do and we don't - in otherwords, it depends on where measurements are being applied.

In areas of technical production (military, automotive, etc.), we use metric.

In home building, food packaging, driving distances and speeds, etc., we use the old system

Personally, I use metric when 'scaling up' drawings when scratch-building balsa flying scale models. It's so MUCH easier doing 'metric math' – than fooling with dividing 1/32 inches Into 1/64 inch measurements. Lazy? No., smart!

 

[pbehn]

Personally, I use metric when 'scaling up' drawings when scratch-building balsa flying scale models. It's so MUCH easier doing 'metric math' – than fooling with dividing 1/32 inches Into 1/64 inch measurements. Lazy? No., smart!

Do you model in 1/72 1/48 1/36 1/24?

 

[fubar57]

Online Scale Converter Tool - Scale Modelers World

 

[mikewint]

To many of the major kit makers those scales have become "Goals" rather than Exactitudes and in modernish times have in really become a "Fit-the-Box" scale. That way model manufactures can order a large number of 'standard' sized boxes, saving money, and adjust the kit pieces, just a bit, to fit the box. Modeling magazines have been running articles on this for some time

 

[gumbyk]

A Friend of mine made, mid '60s, the last course in piston fighters.
They started the flying school, he told me, with Piaggio's, whose instruments were metric.
Then with T-6, whose instruments were Imperial.
Then with Fiat G-59, whose instrument were metric again
and finally with P-51, whose instruments were Imperial...
Really a mess, He told me, so they painted red stripes everywhere indicating dangerous limits...

It shouldn't be, from a pilot's perspective. All you're looking for is the number on approach. I fly a Tiger Moth in mph, a Nanchang in km/h and any GA aircraft in knots, never had any problem as e.g. approach speed is 60 in the Tiger - 150 in the 'chang.

 

[The Basket]

Murphys law says that some poor sod is going to get his kph and mph mixed up and find themselves on the wrong side of fate.

 

[gumbyk]

Murphys law says that some poor sod is going to get his kph and mph mixed up and find themselves on the wrong side of fate.

Only if getting out of one aircraft and into another of the same type with different gauges. Different aircraft already have different figures for critical speeds, so the numbers are different anyway. However, if you get out of a 172 with an MPH ASI, and into another 172 with an ASI in knots, that's when problems occur - some things the same, but not everything.

 

[Elmas]

It shouldn't be, from a pilot's perspective. All you're looking for is the number on approach. I fly a Tiger Moth in mph, a Nanchang in km/h and any GA aircraft in knots, never had any problem as e.g. approach speed is 60 in the Tiger - 150 in the 'chang.

Of course it shouldn't be...
but it was...