"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



We competitive cyclists use dimples already on our disk wheels. And some
skinsuits incorporate them. But they don't look like the dimples on a golf
ball. They are shaped differently and they are shallow.

Check out Zipp disk wheel dimples he
http://www.zipp.com/wheels/detail.php?ID=33

Over a 40K ITT this rear wheel can give you a 30-40 second advantage over
smooth disk wheels.

--
Gregory Hall