spacesailor Posted December 17, 2015 Share Posted December 17, 2015 The metric system (more accurately International System of Units) has a certain elegance in that it covers all measurements with combinations of just 7 base units, six of which are defined as natural constants, a When I went to school so many decades ago There were 12 units, six above the base & six below. The "International System of Units" IS Paris France!, don't hide it. And don't say to the French, 600 Milli liters of milk please. (the old pint bottle). Boy did I ever get bashed for not understanding that foreign system. Link to comment Share on other sites More sharing options...
facthunter Posted December 17, 2015 Share Posted December 17, 2015 Surprisingly, I believe we coped well with the mixture, in aviation, having been set up for disaster by the experts. The system you quote as australian, Isn't. All over the world there are variations. In australia, it depends on the time the aircraft was introduced and the policy of the operating airline. The B 727 was operated under different systems in the one country by different airlines. TAA used Lbs Ansett went metric. with the same plane. All the weights were rounded off in thousands in the original US Lbs in the manual produced by Boeing , 1,000s of Lbs stated and converted to metric produces no even numbers at all. This isn't a disaster, just untidy. The metric system is more orderly and sensible, regardless of who gets the blame /credit for it. Most of the world has altimeters in feet but there are exceptions Russia Indonesia and a few others use meters. 1,000 feet is a good vertical separation . Converted to meters it isn't an easy figure to read on an altimeter, which happens to be one of the most accident causing instruments in the cockpit, already. Nev Link to comment Share on other sites More sharing options...
Maritime_Ev Posted December 17, 2015 Share Posted December 17, 2015 When I went to school so many decades ago There were 12 units, six above the base & six below.The "International System of Units" IS Paris France!, don't hide it. And don't say to the French, 600 Milli liters of milk please. (the old pint bottle). Boy did I ever get bashed for not understanding that foreign system. I think you're confusing the base units and the prefixes. The base units are meter, kilogram, second, kelvin, ampere, candela, mole. With those you can derive all other units (Newton, joule, volt, etc) that's the beauty of the system, and the reason it is used for scientific purposes worldwide. BTW According to Wikipedia this idea was pioneered by Maxwell and Kelvin, so not all foreign (tho that depends on your point of view, they're foreign to me). The prefixes are the nano, kilo, yota, etc. I thought there were 10 up and down but it could be twelve, I rarely use anything smaller than micro or bigger than terra. I agree that the French can be a bit difficult when you're not fluent the local lingo, but that has little to do with how well the system works. And while most people in the Netherlands speak some English asking for a pint of milk in a Dutch supermarket might give you a few frowns too, quite like asking for a liter in the US 1 Link to comment Share on other sites More sharing options...
spacesailor Posted December 17, 2015 Share Posted December 17, 2015 Hi,Maritime_Ev You missed "Henry" if thats the right spelling, didn't I get the base unit right, 6 above the Meter & 6 below it. six-hundred milli-litres is equivalent to one pint, but it's six deca-litres in Europe. spacesailor Link to comment Share on other sites More sharing options...
Yenn Posted December 18, 2015 Share Posted December 18, 2015 I prefer cubic centimetres. CC's but that is OK. Still don't know how many cc's to a cubic inch. Link to comment Share on other sites More sharing options...
facthunter Posted December 18, 2015 Share Posted December 18, 2015 61 cubic inches is one litre. (1,000 cc's). Engine capacity is usually in litres or cubic inches. That's about all I memorise except 1 mm equals .3937 inches if I'm calculating carefully or 40 thou roughly. Nev Link to comment Share on other sites More sharing options...
Oscar Posted December 18, 2015 Share Posted December 18, 2015 If you all think imperial to metric is a mess ( and I share that opinion), try to compare the published capabilities of vacuum pumps! I have a 'Unit Converter' on my computer ( the one I use is ' Inventive Design Unit Convertor Professional'), and it can do things to things I have never heard of or imagined exist; I swear it can, probably, convert kilowatt hours to Cat rubs per foot of Acrylic rod - but rationalising between all the various forms of quoting vacuum defeats it. When trying to sort out a suitable pump for vacuum-bagging of wing skins etc., I ended up standing on my head with my underpants over my ears, singing the Marseillaise backwards in Olde Norske, it helped me regain sanity. Now, I am ok, as long as I keep taking the medication. 3 1 Link to comment Share on other sites More sharing options...
facthunter Posted December 18, 2015 Share Posted December 18, 2015 It's one thing to know the formula but another to know and use the appropriate units. Nev Link to comment Share on other sites More sharing options...
Oscar Posted December 18, 2015 Share Posted December 18, 2015 61 cubic inches is one litre. (1,000 cc's). Engine capacity is usually in litres or cubic inches. That's about all I memorise except 1 mm equals .3937 inches if I'm calculating carefully or 40 thou roughly. Nev May I politely point out that even the venerable BMC 'A" series engine, was categorised in CC's? Trumpy's and Beezers, AFAIK, were also; the only bike engine I can readily think of that was and basically remains an 'incher', belongs to Harleys. And yet, for the most sophisticated motorcycle racing class in existence - motoGp, for which ALL the manufacturers are metric-country-based, and a motoGp bike is arguably every bit as sophisticated as an F1 car and costs typically well north of $1m euro, while the engine capacity is quoted in metric, the wheel rim sizes are quoted in inches. Link to comment Share on other sites More sharing options...
facthunter Posted December 18, 2015 Share Posted December 18, 2015 More relevant though, aircraft are as I stated. US engine specs Like IO 235 (if it exists) is an Injected Opposed 235 cubic inch engine. A DC3 engine is a P&W R 1830, Radial 1830 cu. in. so you get a rough idea what it looks like and how big it is. Nev Link to comment Share on other sites More sharing options...
old man emu Posted December 20, 2015 Share Posted December 20, 2015 This morning Old Ma Emu was preparing a good old Sunday fry up for our breakfast and wanted to toast some potato waffles under the griller. It seems that the instructions said to have he waffles 10 cm beneath the griller element, so she asked me how big 10 cm was. Knowing that a picture is worth a thousand words, I made two fists and extended my thumbs, touching their ends to make a space separating the fists. 'That's space is roughly 10 cms," I said. How did I know? Well the distance between the tip of my thumb and the first knuckle is 1 " which is 2.54 cm. The length of my second thumb joint is about the same, so from the tip of my thumb to the side of my index finger is about 5 cm. Twice that is 10 cm. So the ancient measurements based on the length of body parts work in both the Metric or Imperial systems. I hope I haven't just opened my mouth and put my 30 cms into it. OME Link to comment Share on other sites More sharing options...
Geoff13 Posted December 20, 2015 Share Posted December 20, 2015 My wife keeps telling me that men do not know sizes, only Women know size. Link to comment Share on other sites More sharing options...
pmccarthy Posted December 20, 2015 Share Posted December 20, 2015 There was once a man with twelve inches but he didn't use it, as a rule. Link to comment Share on other sites More sharing options...
hihosland Posted December 20, 2015 Share Posted December 20, 2015 There was once a man with twelve inches but he didn't use it, as a rule. ‘cause he being a disciple of Boole Embraced his version of logic And avoiding the acid lysergic did shine as dux of his school Link to comment Share on other sites More sharing options...
planedriver Posted December 21, 2015 Share Posted December 21, 2015 Sounds to me like you were talking about the "feet", "nautical miles" and "knots" used worldwide in aviation before the discussion quickly drifted to metric versus imperial generally speaking.To understand this you have to go back to the end of World War 2 and the dominance of the USA around the world, supported by the British. The adoption of standardised units in aviation was a consequence of the Chicago Convention in 1944 and subsequent post-war years. The general thrust was to adopt the metric system universally for aviation. However the nautical mile was included due to it's relevance in map usage (being one minute of latitude on maps and charts). Hence also "knots" or "nautical miles per hour" for speed. Even so, there's no specific reason it couldn't be adapted to kilometres but it remains as it is for convenience. The foot for altitude was purely a result of American and British insistence. There's absolutely no reason it should be used for altitude, but he who wins the war writes the post-war rules. As to metric versus imperial measurements for other purposes, again you have to look at the aircraft and general manufacturing juggernaut of the USA after the war. There's not actually a lot about the old imperial measurements which makes logical sense in the modern day, but trying to get a powerful nation with significant world influence to change is....well....not all that easy. Technically the USA is supposed to have changed to metric (Congress authorised it back in 1975), but practically the country has largely refused to do so mainly due to the sheer cost and effort it would require. Put simply, it's "too hard". It hasn't been without consequential trauma either. NASA lost a $125 million Mars probe in 1999 as a direct result of confusion between imperial and metric measurements. In 2006 a remote NASA spacecraft rammed into a military satellite it was meant to dock with for the same reason. Interestingly I witnessed a discussion on metric versus imperial between two American engineers not long ago. One designed and built aircraft, the other was involved in precision CAD manufacturing. The aircraft guy was arguing that he found it easier to think in terms of the old fashioned imperial units (probably because that's just what he grew up with). The precision manufacturing guy argued the complete opposite, saying that in his line of business, nothing about the old system made any sense and metric was far better. When you think about it, metric measurement is a natural "base 10" system just like we use in mathematics everywhere in the world (including the USA). I personally can't see why they hang onto imperial, other than the old "it's just too hard to change" reason. So true Dutch, i'd be happy to shout you a pint for your great answer:spot on: 1 Link to comment Share on other sites More sharing options...
dutchroll Posted December 21, 2015 Share Posted December 21, 2015 So true Dutch, i'd be happy to shout you a pint for your great answer:spot on: I am intimately familiar with the pint as a unit of measurement! 1 1 Link to comment Share on other sites More sharing options...
facthunter Posted December 21, 2015 Share Posted December 21, 2015 One litre steiner? of german beer in Venice. Seemed like a lot at the time but it was midsummer so PERFECT. Nev 2 Link to comment Share on other sites More sharing options...
Old Koreelah Posted December 21, 2015 Share Posted December 21, 2015 I am intimately familiar with the pint as a unit of measurement! ...probably the only imperial measurement I miss! 1 1 Link to comment Share on other sites More sharing options...
facthunter Posted December 21, 2015 Share Posted December 21, 2015 Funny that. Never use it never think about it and I'm not young.. Pretty much a litre person, but I still convert litres/100kms to MPG. Completely chucked pints, quarts and gallons. Nev Link to comment Share on other sites More sharing options...
Old Koreelah Posted December 21, 2015 Share Posted December 21, 2015 Me too Nev. I still convert back to compare with performance of bikes and cars yonks ago. Multiply km/l by 2.824= mpg. 1 Link to comment Share on other sites More sharing options...
old man emu Posted December 21, 2015 Share Posted December 21, 2015 Me too Nev. I still convert back to compare with performance of bikes and cars yonks ago.Multiply km/l by 2.824= mpg. Yeah, but they moved the goalposts and now want to quote fuel consumption in litres per 100 kilometres. When my fuel gauge is hovering near the Big E (only on ground vehicles) I want to know if I can make it to a servo a few kilometres away, or if I should pull over in a safe spot and extend the thumb. My bike doesn't have a fuel gauge, but after lots of tests, I know that I get about 10 kilometres per litre. My reserve tank holds just on three litres, so I know that I've got a safe 20 kilometres with reserve before I start walking. Then I just have to convert 20 kms to miles because my odometer is in miles. OME Link to comment Share on other sites More sharing options...
Old Koreelah Posted December 21, 2015 Share Posted December 21, 2015 ...My bike doesn't have a fuel gauge, but after lots of tests, I know that I get about 10 kilometres per litre. My reserve tank holds just on three litres, so I know that I've got a safe 20 kilometres with reserve before I start walking... OME Cripes OME, that's a thirsty bike! Even my mate's red Mach III, if nursed carefully, could get 24 mpg. I discovered the hard way that my Ducati had a range on reserve of 11 km. Fixed that by fitting taller tubes inside the fuel taps. Link to comment Share on other sites More sharing options...
dutchroll Posted December 21, 2015 Share Posted December 21, 2015 Funny that. Never use it never think about it and I'm not young.. Pretty much a litre person, but I still convert litres/100kms to MPG. Nev I certainly consider myself "bilingual" when it comes to metric vs imperial (the final metrification in Aus was being completed when I was a young kid) and mpg was still the main "fuel economy" unit for years even after car speedos all went metric. However day to day I've always preferred metric as the unit subdivision (kilo, centi, milli, etc) is common across the board. Workshop stuff I'm quite familiar with both though, as would anyone else with a shed/workshop. You pretty much can't function unless you know mm to inches and kg to lb! 1 Link to comment Share on other sites More sharing options...
facthunter Posted December 21, 2015 Share Posted December 21, 2015 Me too Nev. I still convert back to compare with performance of bikes and cars yonks ago.Multiply km/l by 2.824= mpg. I do both Old K. If I'm talking to a car or bike salesperson I do the litres/100 kms deal or Kms/litre. Distance in New Zealand is in hours. Nev Link to comment Share on other sites More sharing options...
Kiwi303 Posted December 22, 2015 Share Posted December 22, 2015 Yeah, I get around 5 hours to a tank. Enough from Chch to not quite reaching Nelson. Link to comment Share on other sites More sharing options...
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