From: CHRISTOPHER_ZAVATSON@udlp.com
Date: Mon, 18 Jan 1999 08:20:39 -0600
Message-ID: <001ED161.C21254@udlp.com>
Subject: 45 tapes, carb air box, magnetos and vac pumps
To: Lancair.list@olsusa.com
Mime-Version: 1.0

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     Scott,
     
     Regarding cooling magnetos:  I was asking myself the same question a 
     few months ago.  First I called up Unison to get operating 
     temperatures for the Slick Mags on my O360A1A.  Normal operating range 
     is 180-210 deg F measured on the case in the coil location.  I then 
     epoxied a thermo couple to the left mag and place two more 
     thermocouples 1/4 inch off both mags to measure local air 
     temperatures.  With the readouts in the right seat I went flying.  
     OATs were in the 70-80 F range.  I was suprised at how low the 
     temperatures were.  Steady state was reached at about 130 F. The air 
     temperature consistently lagged the magneto temperature by 10 F.  I 
     continued with landings and taxiing back for take off.  I figured the 
     lack of air flow might bring the temperatures up.  It did, but not 
     very much.  The highest temperature measured was 170 F.
     As a result of these measurements I have elected to skip magneto 
     cooling.  I will repeat these measurements once our local temperature 
     hits 100 deg F this summer to make sure recommended operating 
     temperatures are still not being exceeded.
     I have the long engine mount, a carburated O360, and my oil cooler 
     exhausts into the engine compartment in front of the #2 cylinder.  The 
     air behind the engine must really be whipping around, because it is 
     doing a great job cooling the mags.
     
     Chris Zavatson
     N91CZ