** Caution: EXTERNAL Sender ** Stephen, Mike I agree with Mike that kWh/100 km is better than kWh/100 miles, especially if you want to compare costs with petrol-driven models.
Suppose that petrol consumption is P litres/100 km, that electrical energy consumption is E kWh/100 km, that petrol costs x per litre and that electricity costs y per kWh, then the cost of petrol to drive 100 km is xP and the cost of electrical energy to drive the same distance is yE. These two results can be compared as they represent the same thing. The moment we start talking about kWh/100 miles and L/100 km, we need to throw in conversion factors. The big problem with metrication in the United Kingdom is the lack of government leadership. Thus people who are classic car enthusiasts will continue ot use imperial units while engineers will use metric units and when the two talk to each other, we get a “Very British Mess”. Martin From: USMA <usma-boun...@lists.colostate.edu> On Behalf Of Metricmike Sent: Monday, August 26, 2024 11:40 AM To: USMA List Server <usma@lists.colostate.edu> Subject: [USMA 2054] Re: SAE ** Caution: EXTERNAL Sender ** Stephen, You and I might be native English speakers but we talk a different measurement language, you can tell me how many miles per gallon you get which to me is meaningless, it's also meaningless to Americans because their gallon is smaller. kWh/100 miles is also meaningless to the rest of the English speaking world as every country except the USA and the UK use something else. In the US it's mpg equivalent., the rest of the planet uses L/100km. Same problem with weight the only people on the planet using stones are the UK, except for hospitals where drugs are given in grams or milligrams per kilogram of body mass. And there is the problem, creatures from another world. Mike Payne On 26/08/2024 01:53, Stephen Humphreys wrote: I was at a show today at Silverstone (a huge classic car event) The electric cars had kW and BHP (oddly there was also plain hp) they also quoted kWh/100 miles On 25 Aug 2024, at 10:51 pm, vliets...@btinternet.com<mailto:vliets...@btinternet.com> wrote: Why do salesmen insist on using units of measure that are different to those that are used by the design engineers? One of the first things that is taught is A Level physics is the importance of the right degree of precision. Let me explain: 1. Eurostar travels at speeds of up to 186 mph. What is special about 186 mph? Was this a speed that was actually measured in a trial? No, it was a conversion of 300 km/h which is the criteria that the design engineers were given. 1. A week or two ago, we learned that Ukraine had captured 386 square miles of Russian territory. That sounds a fairly exact number. In reality, the Ukrainian reported that they had captured 1000 square kilometres of territory, but the British journalists took out their calculators and converted it to square miles. At a first guess, I would say that when the Ukrainians say that they took 1000 square kilometres, they might mean anything between 900 and 1100 (ignoring the possibility of exaggeration), but if I read 386 square miles, that tells me something between 385 and 387 – in other words, the UK journalists have not told the whole truth. Unfortunately our government has very few people who have studied a STEM discipline so they fail to see the things that make engineers wince. Why do the car handbooks use different units of measure to the units of measure given in advertising literature? It is because the handbooks were written by technical authors working with engineers while advertising materials were written by advertisers who are often known for being “economical with the truth”. Finally, why is it that my handbook gives tyre pressures in bars, but the air pumps at all service stations default to psi? Martin. From: Stephen Humphreys <barkatf...@hotmail.com<mailto:barkatf...@hotmail.com>> Sent: Sunday, August 25, 2024 7:19 PM To: vliets...@btinternet.com<mailto:vliets...@btinternet.com> Cc: Michael Payne <metricmik...@gmail.com<mailto:metricmik...@gmail.com>>; USMA List Server <usma@lists.colostate.edu<mailto:usma@lists.colostate.edu>> Subject: Re: [USMA 2048] Re: SAE When buying a car Bhp is used. Kw won’t mean much to the average Brit. All the British car tv programmes use bhp too Sent from my iPhone On 23 Aug 2024, at 2:07 PM, vliets...@btinternet.com<mailto:vliets...@btinternet.com> wrote: Hi Steve, Mike I decided to check this site out: https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.volkswagen.de%2Fde%2Fmodelle.html&data=05%7C02%7Cusma%40lists.colostate.edu%7C4a3a746eabd84fc5997f08dcc5dfaab6%7Cafb58802ff7a4bb1ab21367ff2ecfc8b%7C0%7C0%7C638602811650001448%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C0%7C%7C%7C&sdata=uOuiMFuedb3IsRKig6yS77QOYmUR0oSauQfj4%2FPsxu8%3D&reserved=0<https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.volkswagen.de%2Fde%2Fmodelle.html&data=05%7C02%7Cusma%40lists.colostate.edu%7C4a3a746eabd84fc5997f08dcc5dfaab6%7Cafb58802ff7a4bb1ab21367ff2ecfc8b%7C0%7C0%7C638602811650001448%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C0%7C%7C%7C&sdata=uOuiMFuedb3IsRKig6yS77QOYmUR0oSauQfj4%2FPsxu8%3D&reserved=0>. In case you are wondering, it is the German language site for Volkswagen aimed at the German market. You don’t need to be able to read German to follow it, but certain specifications like “59kW”, it is pretty obvious what they are referring to. I could not find any reference to “PS” on this site. Kind regards Martin From: USMA <usma-boun...@lists.colostate.edu<mailto:usma-boun...@lists.colostate.edu>> On Behalf Of Stephen Humphreys Sent: Wednesday, August 21, 2024 10:27 PM To: Michael Payne <metricmik...@gmail.com<mailto:metricmik...@gmail.com>> Cc: USMA List Server <usma@lists.colostate.edu<mailto:usma@lists.colostate.edu>> Subject: [USMA 2048] Re: SAE ** Caution: EXTERNAL Sender ** Ive only seen car power in bhp and torque in lb/ft. I’ve been a ‘car nut’ all my life The Germans use a horsepower too - PS - which is slightly different On 20 Aug 2024, at 8:20 pm, Metricmike <metricmik...@gmail.com<mailto:metricmik...@gmail.com>> wrote: ** Caution: EXTERNAL Sender ** Thanks John, It is good to hear the SAE have progressed, I've know for about 40 years that all vehicles manufactured in the USA are metric, with some odd bits and pieces perhaps still in inches. Is there a document I could access for quoting this policy? Mike Payne On 20/08/2024 13:26, John Steele wrote: I worked for one of the Big Three automotive companies and was an SAE member (I've been retired for some time). The SAE is primarily metric. I don't have the current edition, but quoting from SAE TSB003 (1999), their metric policy is: In 1969, the SAE Board of Directors issued a directive that "SAE will include SI units in SAE Standards and other technical reports." During the ensuing several decades, SAE metric policy evolved and implementation progressed. The SAE’s current metric policy is, "Operating Boards shall not use any weights and measures system other than metric (SI), except when conversion is not practical, or where a conflicting world industry practice exists." I bolded the word "not" which is underlined in the standard. TSB are standards from the Technical Standards Board, applicable to all SAE groups. TSB003 was originally published as SAE J916, first published in 1965. I'm sure it was originally a much weaker statement on metrication, but I do not have copies of previous versions. My experience was that this was well followed by all groups in Ground Transportation (Light Vehicle, Heavy Truck& Coach, Offroad). There is an aviation group about which I know little; however, they do maintain a number of SAE standards on Customary fasteners used in aviation because it is a world-wide practice. The rest of the standard mentioned above is the SAE's metric use standard which also references ANSI SI10, NIST SP 330, and some other metric standards. As it is copyrighted, I can' t post it here. As for automotive, I worked elsewhere for 10 years after college and joined automotive in 1978. I assume the other two companies were on about the same track. Mine was substantially metric (for new design) when I joined and I am guessing metrication began around 1973. A few 1978 models were substantially metric, and all future models I worked on in engineering were metric. Some older models, originally designed in Customary, continued until the end of the platform life so the early 80's were mixed. However, a lot of conversions are done for marketing. No one in the US wants their engine power in kilowatts even though we measure it that way; they want horsepower, and we will convert anything to move $40k of metal. All specs in the owner's manual are dual unit, but marketing material is pretty much all Customary. On Tuesday, August 20, 2024 at 05:56:52 AM EDT, Metricmike <metricmik...@gmail.com><mailto:metricmik...@gmail.com> wrote: ** Caution: EXTERNAL Sender ** I see SAE is now SAE international. The article in Wikipedia states in an article titled SAE International: SAE units For historical legacy reasons, the label "SAE" is commonly used on tools and hardware in North America to indicate United States customary units<https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FUnited_States_customary_units&data=05%7C02%7Cusma%40lists.colostate.edu%7C4a3a746eabd84fc5997f08dcc5dfaab6%7Cafb58802ff7a4bb1ab21367ff2ecfc8b%7C0%7C0%7C638602811650001448%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C0%7C%7C%7C&sdata=IQvIErGchg%2Fvq8sS8cwwN73G72op10lIsGpl59hJi4I%3D&reserved=0>measurements, that is, inch<https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FInch&data=05%7C02%7Cusma%40lists.colostate.edu%7C4a3a746eabd84fc5997f08dcc5dfaab6%7Cafb58802ff7a4bb1ab21367ff2ecfc8b%7C0%7C0%7C638602811650001448%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C0%7C%7C%7C&sdata=p5QkCsvoyAeFwtlQt2HyS9qglYylesOB33zrlojELCY%3D&reserved=0>-based not metric (SI)<https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FMetric_system&data=05%7C02%7Cusma%40lists.colostate.edu%7C4a3a746eabd84fc5997f08dcc5dfaab6%7Cafb58802ff7a4bb1ab21367ff2ecfc8b%7C0%7C0%7C638602811650001448%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C0%7C%7C%7C&sdata=sQW%2BisbaZvLHJ2P6seFvAsRriDl%2FKqQLAP6v86pUKSc%3D&reserved=0>. Both this usage and casual use of the term "Imperial<https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FImperial_units&data=05%7C02%7Cusma%40lists.colostate.edu%7C4a3a746eabd84fc5997f08dcc5dfaab6%7Cafb58802ff7a4bb1ab21367ff2ecfc8b%7C0%7C0%7C638602811650001448%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C0%7C%7C%7C&sdata=QMW9FOM2CVhX8N08TuU3ghuY0kQO1bj8lp7zGz81Go8%3D&reserved=0>" are loose and imprecise (but common) references to inch fractional sizes and to the screw thread<https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FScrew_thread&data=05%7C02%7Cusma%40lists.colostate.edu%7C4a3a746eabd84fc5997f08dcc5dfaab6%7Cafb58802ff7a4bb1ab21367ff2ecfc8b%7C0%7C0%7C638602811650001448%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C0%7C%7C%7C&sdata=tfCYKdXNyxh668mtCPCa4gidsnTRZpGFPByrLaad0%2Fs%3D&reserved=0> sizes of the Unified Thread Standard<https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FUnified_Thread_Standard&data=05%7C02%7Cusma%40lists.colostate.edu%7C4a3a746eabd84fc5997f08dcc5dfaab6%7Cafb58802ff7a4bb1ab21367ff2ecfc8b%7C0%7C0%7C638602811650001448%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C0%7C%7C%7C&sdata=F5j%2FaW7PvVkGd%2FnLmuay%2FasED29ycmMpca6%2BsMlKjoQ%3D&reserved=0> (UTS). SAE is also well known in the United States for its ratings of automobile horsepower<https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FHorsepower&data=05%7C02%7Cusma%40lists.colostate.edu%7C4a3a746eabd84fc5997f08dcc5dfaab6%7Cafb58802ff7a4bb1ab21367ff2ecfc8b%7C0%7C0%7C638602811650001448%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C0%7C%7C%7C&sdata=FmjrrtwYPac%2FEQ3jkm2%2BVnagSIhsxT8MfRSYXQ0oZTM%3D&reserved=0>. Until 1971–1972 SAE gross power was used. Similar to brake horsepower<https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FBrake_horsepower&data=05%7C02%7Cusma%40lists.colostate.edu%7C4a3a746eabd84fc5997f08dcc5dfaab6%7Cafb58802ff7a4bb1ab21367ff2ecfc8b%7C0%7C0%7C638602811650001448%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C0%7C%7C%7C&sdata=9hFLZdDoYEiZgre9K62dAlpfX5KkUz9MsdzX1zWZDN0%3D&reserved=0>(bhp), it gave generously unrealistic performance ratings. Since then the more conservative SAE net power, which takes into account engine accessory, emissions, and exhaust drags (but not transmission losses) is the standard. Horsepower ratings SAE has long provided standards for rating automobile horsepower<https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FHorsepower%23Society_of_Automotive_Engineers.2FSAE_International&data=05%7C02%7Cusma%40lists.colostate.edu%7C4a3a746eabd84fc5997f08dcc5dfaab6%7Cafb58802ff7a4bb1ab21367ff2ecfc8b%7C0%7C0%7C638602811650001448%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C0%7C%7C%7C&sdata=Q675AVGk86RbHaxv3ThMOQLQyqxq%2B8yhFivU8yOiuP0%3D&reserved=0>. Until 1971–1972 SAE gross power<https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FHorsepower%23SAE_gross_power&data=05%7C02%7Cusma%40lists.colostate.edu%7C4a3a746eabd84fc5997f08dcc5dfaab6%7Cafb58802ff7a4bb1ab21367ff2ecfc8b%7C0%7C0%7C638602811650001448%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C0%7C%7C%7C&sdata=V7r6OiLQ2gcpLtm4HLd24t4u%2FHZhqTXrQfb6REY5m8A%3D&reserved=0> was used. Similar to brake horsepower<https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FHorsepower%23Brake_horsepower&data=05%7C02%7Cusma%40lists.colostate.edu%7C4a3a746eabd84fc5997f08dcc5dfaab6%7Cafb58802ff7a4bb1ab21367ff2ecfc8b%7C0%7C0%7C638602811650157705%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C0%7C%7C%7C&sdata=XnI9F7lm8g0BC9kyOEieYZTvBMCUw3%2FP28M12E%2F31tQ%3D&reserved=0> (bhp), it gave generously unrealistic performance ratings. Since then, the standard has been the more conservative SAE net power<https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FHorsepower%23SAE_net_power&data=05%7C02%7Cusma%40lists.colostate.edu%7C4a3a746eabd84fc5997f08dcc5dfaab6%7Cafb58802ff7a4bb1ab21367ff2ecfc8b%7C0%7C0%7C638602811650157705%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C0%7C%7C%7C&sdata=aq7%2BA0p5xw7QAEJMbV%2FtspK%2BKPtWFyZf0vnK3jVcPlo%3D&reserved=0>, which takes into account engine accessory, emissions, and exhaust drags, but not transmission losses. Does anyone know if they still use inch/pound units or have converted to SI? Mike Payne _______________________________________________ USMA mailing list USMA@lists.colostate.edu<mailto:USMA@lists.colostate.edu> https://lists.colostate.edu/cgi-bin/mailman/listinfo/usma _______________________________________________ USMA mailing list USMA@lists.colostate.edu<mailto:USMA@lists.colostate.edu> https://lists.colostate.edu/cgi-bin/mailman/listinfo/usma
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