Glenn writes: >I don't see how changing the prop tips would prevent supersonic unless the >diameter was also reduced. Supersonic speed would just be a function of prop >arc circumference and RPM . RPM X 60 is Revs per hour, this times the >circumference in feet is feet per hour . this divided by 5280 is MPH. My >guess is if this MPH number exceeded the speed of sound at the altitute you >are flying the prop tips go supersonic. Lots of untralights with high reving >engines use smaller diameter three blade props for this reason.
Using these numbers on a 72-inch prop on our C-85 engine that cruises at 2400rpm...the prop tips are moving, at most, 513 mph...well short supersonic! Sorry about that Jack! I still would like to see a 3-blade prop on my coupe! Anybody know anything about the possibility? Pete, N3552H -------------------------------------------------------------------------- --- E. T. "Pete" Petrie Computer Science at My friend Dean Brock says, "Either you Wilkes Community College believe in the Law of the Excluded Middle Box 120, Collegiate Drive or you don't." Me...I'm a little fuzzy Wilkesboro, NC 28697 about it! Fon: 336.838.6185 9am-4pm EST Fax: 336.838.6277 24 hours -------------------------------------------------------------------------- -- -
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