From: Vincent Cate (vince@offshore.ai)
Subject: Re: JP Aerospace and rotating sun toy
 
View this article only
Newsgroups: sci.space.policy
Date: 2004-05-09 22:34:50 PST

The toy is called a Radiometer and the effect is the
"radiometric effect". You can see a picture of one at:
    http://store.yahoo.com/explo/radiometer.html
 
The rest is some notes I made about URLs I found with google.

   - Vince
 
http://www.globalwarmingsolutions.co.uk/crooks_radiometer_and_otheoscope.htm
   several orders of magnitude greater than solar sail force
   10E-3 to 10E-4 atmospheres
 
   "Reynolds and Maxwell proposed an explanation involving
    'thermal transpiration' but even today there is still no complete
     explanation of how this little toy works."
 
   "There has been no attempt to harness the rotational energy to
     measure the efficiency of conversion but I suspect that solar
     is converted into rotational energy with very high efficiency
     in the radiometer."
 
http://www.betrisey.ch/presbok11.htm
     "The mechanism by which it operates is very complex and
        frequently stated incorrectly."
     Experiments seem to indicate "thermal transpiration" is at least
       most of what is going on.
 
http://students.cec.wustl.edu/~sapphire/subsystem/adc/radiometer/radiometer.html
  AMSAT people used radiometric effect to induce 1/2 rpm in 3 weeks
time
 
http://eotvos.dm.unipi.it/nobili/opendiscussion/radiometer_PRD_2001.pdf
    Left side of page 2 has formula for "radiometric effect" given
       temp, pressure, ...
 
http://eotvos.dm.unipi.it/nobili/opendiscussion/radiometer_microscope_revised.pdf
    Has formula
 
http://science.howstuffworks.com/question239.htm
   Crookes' radiometer
 
http://math.ucr.edu/home/baez/physics/General/LightMill/light-mill.html
   Thermal transpiration / light-mill
   Thrust comes at the edges - discounts many other explanations
 
http://sargentwelch.com/product.asp?pn=WL1734%5FEA
   $10 - 99% evacuated - gas expands on black side and so pushes
   This looks like the one I have
 
http://scientificsonline.com/product.asp_Q_pn_E_3116000
   Hand made radiometers.
   "Energy is released as the heated molecules kick away at great
    speeds, causing the vanes to revolve within the vacuum."