Date: 27 Aug 99 03:08:02 From: Goran Begicevic <firstname.lastname@example.org> Organization: TIDAX AB References: 1
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Hmmm...this tends to be a bit complicated calculation. Energy(Joule)=Force(Newton)*distance(meter) Power(Watts)=Energy(joule)/time(seconds) One horsepower(mumbo-jumbo unit) = 746 Watts Now using simple calculations would mean that jet engine spooling up on takeof doesn't produce any power, beacuse brakes are applied and airframe aint going anywhere. In reality, engine is moving air in- and out from engine heating it up, thus doing the work. Measuring power on ordinary piston-engines is straightforward procedure of attaching them to engine-dyno. Jet engine is more complicated. You could attain approximate HP-figure of jet engine by measuring how many 1000HP piston-engines you need to push same aircraft trough air at same speed. Unfortunately, this gets fuzzy beacuse propellers ain't that efficient at higher speeds. Your approach of measuring HP/figure as thrust*distance is wrong, beacuse airframe with less drag will have higher speed with same thrust applyed, inducing false results. In my opinion, one of few reliable ways of measuring this is finding out what's drag-figure for an airliner at speed on full throttle, and multiplying it with airliners speed, divided with number of engines. Just my 5 cents, correct me if i'm wrong.