Bill
Bernie Hunt developed my earlier work on whirling arm rigs for which he may have used weights to provide the torque. I myself used a rubber motor about the same size as one would use in flight and installed a drag plate to ensure that the prop advances at the flying speed ofthe model. The main problem is the small size of my living room, restricting the radius to 3'. The prop flies in its own wake which is stronger for smaller radii and this effect is probably quite significant. The results were purely comparative and I believe the best prop was that which used the least torque.
The electric motor is a good idea in principle.
----- Original Message -----
From: Bill Gowen
To: Indoor_Construction_at_yahoogroups.com
Sent: Monday, April 30, 2007 7:51 PM
Subject: Re: [Indoor_Construction] Testing props
Marty
I haven't seen a device like you describe, but I've often thought that an electric motor would be the way to go on any kind of prop testing apparatus. Bernie Hunt has done prop testing with a whirling arm rig that probably gives more useful data than a static test device. I don't know what he used to drive the prop. To me the electric motor would be ideal because you could vary the voltage to adjust the torque to the prop to whatever value you wanted. It seems like this would be really good for VP testing. If you decide to do this, please report any results!
----- Original Message -----
From: Martin Alderman
To: Indoor_Construction_at_yahoogroups.com
Sent: Monday, April 30, 2007 8:58 AM
Subject: [Indoor_Construction] Testing props
I remember seeing a prop testing jig (was it in INAV?) that used a rubber motor on the tested prop, and applied a force to a scale. Has anyone tried to develop a prop testing jig that uses a PASCO, Vernier, or other force sensor linked to a computer for direct data acquisition? I have a couple of ideas on how to do it, but don't want to reinvent the wheel! For one thing, I'd like to eliminate the rubber motor, at first, and use something more uniform like a cell phone vibe motor. (What I NEED, more than anything else, is the time to work on the concept!)
Your thoughts?
Marty
Martin Alderman
Physics Teacher!
Fayetteville-Manlius High School
8201 East Seneca Turnpike
Manlius, NY 13104
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Received on Thu May 03 2007 - 04:12:56 CEST
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