Pat: Please check your 747 fuel consumption. I believe you will find more like 16 L/km. See http://en.wikipedia.org/wiki/Boeing_747 For 747-400, max fuel is 216 840 L, max range 13450 km. At 16L/100 km, 2200 L would suffice.
--- On Fri, 9/18/09, Pat Naughtin <[email protected]> wrote: From: Pat Naughtin <[email protected]> Subject: [USMA:45828] Fuel efficiency – joules per metre To: "U.S. Metric Association" <[email protected]> Date: Friday, September 18, 2009, 5:38 PM Dear All, I have just read the article at http://www.metrication.us/content/demise-mpg where I was struck by the first paragraph. Even before the advent of partially- or fully-electric cars, it was becoming increasingly apparent that the old fuel economy metric of miles per gallon isn't as useful for measuring energy consumption in vehicles as when it was first codified in the original Corporate Average Fuel Economy standard in the 1970s. That is due in part to the proliferation of new fuels--E85, LPG, LNG, CNG, methanol, and hydrogen--but also because expressing the relationship between distance and volume in this way obscured the diminishing returns to higher levels of fuel economy. As a Wall St. Journal column earlier this week put it, adding electricity into the mpg mix, "risks giving consumers inaccurate information about the financial and environmental costs of driving." But if we need a new metric, what should it measure? I think that the time is rapidly approaching for energy to be measured in the only SI energy unit – joule – and that old pre-metric measuring words for fuel efficiency should be converted to the only SI unit available for energy efficiency for road transport – joules per metre. As a starting reference, here are some examples: Average car 32 megajoules per litre (32 MJ/L) for lead free car fuel, and 10 litres per 100 kilometres (10 L/100 km) fuel consumption, then an average car consumes 3 200 joules of energy for each metre it travels (3 200 J/m). Average truck 38.6 megajoules per litre (38.6 MJ/L) for diesel fuel, and 40 litres per 100 kilometres (40 L/100 km) fuel consumption, then an average truck consumes 15 440 joules of energy for each metre it travels (15 440 J/m). Average (school) bus 38.6 megajoules per litre (38.6 MJ/L) for diesel fuel, and 35 litres per 100 kilometres (35 L/100 km) fuel consumption, then an average truck consumes 13 510 joules of energy for each metre it travels (13 510 J/m). Average Boeing 747 34 megajoules per litre (34 MJ/L) for diesel fuel, and 16 litres per 100 kilometres (16 L/100 km) fuel consumption, then an average truck consumes 5 440 joules of energy for each metre it travels (5 440 J/m). Summary Car 3 200 J/m Boeing 747 5 440 J/m School bus 13 510 J/m Truck 15 440 J/m As usual, I commend to you the simplicity of SI units and the ease of understanding using whole numbers (see http://www.metricationmatters.com/docs/WholeNumberRule.pdf ). Sadly, I could not find comparative figures for electric cars – even at http://www.optimalenergy.co.za/news/article.php?pk_news_id=112v Cheers, Pat Naughtin Author of the ebook, Metrication Leaders Guide, that you can obtain from http://metricationmatters.com/MetricationLeadersGuideInfo.html PO Box 305 Belmont 3216, Geelong, Australia Phone: 61 3 5241 2008 Metric system consultant, writer, and speaker, Pat Naughtin, has helped thousands of people and hundreds of companies upgrade to the modern metric system smoothly, quickly, and so economically that they now save thousands each year when buying, processing, or selling for their businesses. Pat provides services and resources for many different trades, crafts, and professions for commercial, industrial and government metrication leaders in Asia, Europe, and in the USA. Pat's clients include the Australian Government, Google, NASA, NIST, and the metric associations of Canada, the UK, and the USA. See http://www.metricationmatters.com for more metrication information, contact Pat at [email protected] or to get the free 'Metrication matters' newsletter go to: http://www.metricationmatters.com/newsletter to subscribe.
