Date: 16 Sep 97 02:37:11 From: "Michael F. Lechnar" <email@example.com> Organization: nams References: 1 2
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Karl Swartz wrote: SNIP> > The speed of sound varies with temperature and barometric pressure, > but at average conditions at sea level it's about 760 mph. The fan > of a PW4000-series engine for a 777 has a diameter of 112 inches. > (http://www.pweh.com/lce/pw4074.html) Some simple math says that if > the tips of the blades on a fan of that size are moving at 760 mph, > the fan is turning at 2,280.9 rpm. > > Given how much less than 30,000 rpm that is, I'd say you ought to > win a keg of beer from whomever your bet was with! Pretty good calculating!!! The value of 100% N1 for the various engines on the 777 varies between 2300 and 3300 RPM. Mike Lechnar Aircraft Performance Engineer "If I was speaking for Boeing, I wouldn't be doing it here."