Mailing List lml@lancaironline.net Message #70173
From: Chris Zavatson <chris_zavatson@yahoo.com>
Sender: <marv@lancaironline.net>
Subject: Expriments in iPad Cooling
Date: Tue, 10 Jun 2014 16:44:32 -0400
To: <lml@lancaironline.net>
Throwing out all my paper charts and replacing them with an iPad was a tremendous leap forward in keeping a small cockpit neat and organized.  
Unfortunately the operating environment for which the iPad was designed is a little more benign than what we see in a bubble canopy cockpit of a Lancair two seater.  Specifically the iPad's temperature limit could stand to be a bit higher.  While the iPad only consumes about 5W internally, the solar radiation on the front face is up to 50W.  The iPad can therefore quite readily overheat and brown-out in direct sun light.  Typically, protecting the iPad from direct sunlight prior to launch is sufficient to prevent over-heating.  I have however experienced two brown-outs.

An active cooling option that makes direct sunlight a non-issue would be beneficial.  I have been testing a new iPad mount that incorporates a thermoelectric cooler (TEC).  TECs are neat little devices that with the application of current drive heat from one side through the device to the other. 
 
The iPad back panel is aluminum which is a reasonably good thermal conductor.  The TEC cools only a small area near the processor. Heat is carried away from the TEC using a heat sink and cooling fan.  Thus far test results have been encouraging.  The iPad remains fully functional in continuous direct sunlight despite a surface temperature of 125 deg F.   
more to come....
 
Chris Zavatson
N91CZ
360std
www.N91CZ.net

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