[Land-speed] [BULK]Re: Polar Moment

[neil at dbelltech.com]

Ed;

I've often wondered if I could investigate the aerodynamics of a design by
using a scale model in water instead of air. The drag effects, etc should
show up at quite low speeds in water compared to air since its density is
far higher. Granted, water isn't compressible like air but we're talking
about subsonic vehicles so this may be practical-- what do you think?

My idea is to do the drag measurements with a minimum of instrumentation.
Simply build a smooth ramp and place it in a swimming pool at a known angle
and let the model roll down the ramp for a measured distance. The faster it
covers that distance, the lower the drag. The distance would need to be long
enough for the model to reach its terminal velocity. Make the model fairly
heavy to eliminate the buoyancy effects.

Jon might have to chip a hole in the ice, though :)

Regards, Neil   Tucson, AZ

-----Original Message-----
From: land-speed-bounces+neil=dbelltech.com at autox.team.net
[mailto:land-speed-bounces+neil=dbelltech.com at autox.team.net] On Behalf Of
Ed Weldon
Sent: Wednesday, January 16, 2008 12:20 AM
To: Don McMeekin; Keith Turk
Cc: 'land-speedsubmit'; Elon; NT788 at comcast.net
Subject: Re: [Land-speed] [BULK]Re: Polar Moment


....I wonder if some of the scale model body shapes available like to the RC
model builders are big enough to test in a small wind tunnel.  I even wonder
if this could be a sophisticated "garage project?  Anyone have some
engineering school contacts?  This could be a neat senior or graduate level
project for a mechanical engineering student or a group.

Ed Weldon .....uhhhh........off on the edge again.