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Old November 7th 08, 07:27 PM posted to sci.energy,rec.aviation.homebuilt,rec.aviation.military,rec.aviation.marketplace,sci.engr.mech
Gregory Hall
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Posts: 26
Default Dimples On Model Aircraft Could Greatly Extend Range


"Bret Cahill" wrote in message
...
Have they tried dimples on radio controlled aircraft? The size and
speed could designed around the magic Reynolds number = 100,000 where
the coefficient of drag drops precipitously.

Dimpling could vastly extent the range of large and slow as well as
small and fast radio controlled aircraft.

A competitive cyclist is the right size and speed for Nre = 100,000 so
dimple suits can work. Same for golf balls.

Nre = 100,000 for widebodies going 0.5 knots so dimples won't work
except on the runway.

From fluid mechanics the Reynolds number is the ratio of inertial
forces/viscous forces.

N re = Diameter X velocity X density of fluid/viscosity of fluid.


Bret Cahill



Do her dimples make her faster?

http://underscorebleach.net/content/.../p2/arched.jpg

--
Gregory Hall