<HTML>Hi Guys,
Thanks to everyone for the common sense! I remember saying the same things on other steam forums, and getting the lunatic treatment. "Gas engine = 24% efficient, steam engine = 12%; therefore steam cars use twice the fuel of gas cars, PERIOD, end of discussion!" The gas car boys have some of us brainwashed pretty good. My long, strange trip into steam cars began way back when a friend told me his 1972 Buick Electra got about 10-12 mpg; odd (I thought), that's about the same reported in modern driving for "half the efficiency" 1920s Stanleys & Dobles of similar weight ...
To achieve its theoretically possible ~20% road efficiency at legal highway cruise speed, the gas engine of a typical car has to be no bigger than about 30 hp/kw.. I'd guess its acceleration would then be about 0-60 mph (~0-100km/hr) in around 30 seconds if normally aspirated. Think Yugo. If you want 20% in city driving, forget highway-capable gas engines. Think lawnmower engine. Big difference between full load & part/variable load conditions.
A comparison of gas & steam engine BSFC charts can be deceptive. Steam engines equal/beat gas engines in only a small portion of the chart, at the lower end ("part load"). However, that small portion is exactly where most driving occurs, and most charts don't cover transient conditions (accelerating/decelerating). When idling at a stop, the efficiency of a gas engine is less than zero. And don't forget the higher fuel consumption in short trips, when the gas engine/tranny are warming up (Ted Pritchard does mention this on his website, with engineering literature references). On many short trips, the gas car never warms up completely, and short trips cover a large chunk of automobile use.
One bright spot is that my efficiency article, linked earlier in this thread, is going to be excerpted in a high school science textbook in the fall. I filled out & sent back the reprint permission forms a couple months ago, and now wish I'd written & edited the article a little better, instead of as a dashed-off mess of notes & updates for fellow steam fans. Researchers for the book told me the figures matched their research, but they'd never seen all the numbers put together in one comparative article. So maybe some of the young folks will learn something "on the level" in school for a change, not just the above-mentioned century-old Detroit party line. The editors told me that they are also going to reprint some steam car web links, so we may have some budding engineers asking around the Phorum later this year.
More and more web sources (incl Yahoo) now list steam cars as an alternative automotive technology; quite a change from their status as an "Officially Nonexistant" engine or mere historical curiousity for most of the last century.
Jim is right; the steam car is definitely not dead! Just widely overlooked & massively underfunded. When today's "Official Alternatives" graduate to "obvious flop" status, and some good modern steam cars get attention on the road, this may change surprisingly quickly. Get in on the ground floor now, folks. The facts are on our side, and fuel cells and other "Official Alternatives" have already had stock price collapses and technical setbacks.
For more info on many of the gas-hoggin' Clean Air Era steam cars, check out ERDA 17-54, available as a reprint from the SACA Storeroom (item #204). Lots of interesting and useful info. Also see TM 126, on the Dutcher experimental engine. Both from the SACA Storeroom, via the SACA webpage @ [
www.steamautomobile.com]
Peter</HTML>