REFLECTOR: Fw: Mag cooling

[Jim Agnew]

Well, then cooling may not be needed during flight.  My   engine compartment temp ranges from 104-145. Are you measuring between the firewall & the rear engine baffle or the engine baffle & Prop outlet?  

James F. Agnew
Jim_Agnew_2 at Yahoo.Com
Tampa, FL
Velocity 173 Elite Aircraft Completed & Flying

From: Douglas Holub <douglas.holub at gmail.com>
>To: Velocity Aircraft Owners and Builders list <reflector at tvbf.org>
>Sent: Monday, August 15, 2011 1:03 PM
>Subject: Re: REFLECTOR: Fw:  Mag cooling
>
>
>  
>I'm surprised.  I'll stick a temperature probe 
next to the magneto while I'm flying and see what I get. 
>----- Original Message -----  
>>From: aminetech at bluefrog.com  
>>To: Velocity Aircraft Owners and Builders  list  
>>Sent: Monday, August 15, 2011 12:41  PM 
>>Subject: Re: REFLECTOR: Fw: Mag  cooling 
>>
>> 
>>
>>
>>--- douglas.holub at gmail.com wrote:
>>
>>From: "Douglas Holub" <douglas.holub at gmail.com>
>>To: 
  "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org>
>>Subject: Re: 
  REFLECTOR: Fw: Mag cooling
>>Date: Mon, 15 Aug 2011 12:30:27 -0400
>>
>>
>>I didn't realize that magnetos needed to be  cooled. A timely post since I'm replacing one of my Plasma IIIs with a  magneto this week. The last FAQ on Kelly Aerospace's magneto page says that  the ambient temperature around the magneto should be kept below 160 F.  
>>
>>
>>Well, then cooling may not be needed during flight.  My  engine compartment temp ranges from 104-145. 
>>  
>>John 
>>  
>>http://www.kellyaerospace.com/magneto_FAQ.html 
>>  
>>Doug Holub 
>>Standard FG w/ electric nose lift 
>>  
>>Speaking of electric nose lifts, I was at Brett  Ferrell's website this week and learned that the first Velocity prototype was  also a fixed gear with a retractable nose gear. Who knew? 
>>----- Original Message -----  
>>>From: Jim  Agnew  
>>>To: Velocity Reflector  
>>>Sent: Wednesday, August 10, 2011 2:38  PM 
>>>Subject: REFLECTOR: Fw: Mag  cooling 
>>>
>>> 
>>>Click on the following URL to get PIX 
>>>  
>>>https://www.dropbox.com/gallery/7279544/1/2%20Mag%20cooling%20Pix?h=1e980f 
>>>  
>>>James F. Agnew 
>>>Jim_Agnew_2 at Yahoo.Com 
>>>Tampa, FL 
>>>Velocity 173 Elite Aircraft Completed & Flying 
>>>
>>> 
>>>
>>>>
>>>>Hi Dave, 
>>>>  
>>>>Sam Dasilva & I both have the system that is shown in the attached picture.   The 3" 12V fan you can clearly see in the picture.  The fan hole  allows air to come up behind the baffle and is  sucked out by the prop vacuum so you do get some mag  cooling.  What you don't see is a small solid state thermostat  mounted on the back side of the baffle that turns the fan on  when the temp exceeds a certain temp (that I  don't remember so I will check). The fan is permanently supplied with  power and neither of us have ever had the  fan start in flight.  When you shut down after a minute or two the  fan turns on and helps to cool down the engine since the  upper  Cowl tends to trap hot air and natural convection is inhibited.  The  fan gives a boost to starting the convection and normally only runs for a  couple of minutes.  Blast tubes will help with mag cooling, however  you still need an upper baffle air exit.  I  have also attached a pix of
 the baffle back side  that shows the fan &  thermostat.  
>>>> Jim 
>>>>
>>>>James F. Agnew 
>>>>Jim_Agnew_2 at Yahoo.Com 
>>>>Tampa, FL 
>>>>Velocity 173 Elite Aircraft Completed & Flying 
>>>>
>>>>
>>>>From: David Ullman <ullman at robustdecisions.com>
>>>>>To: reflector at tvbf.org
>>>>>Sent: Wednesday, August 10, 2011  12:00 AM
>>>>>Subject: Re:  REFLECTOR: Mag cooling
>>>>>
>>>>>My Tech Advisor asked me to ask if  anyone directs cooling air on to the
>>>>>magnetos?  I have two of 
        them on the back of my IO-360-C1C and they
>>>>>currently get no air 
        circulating over them at all.  Seems easy enough to
>>>>>bleed some 
        off the ducts bringing air into the plenum. Is magneto heating 
        a
>>>>>problem for anyone?
>>>>>
>>>>>David G. Ullman PhD ME
>>>>>Robust 
        Decisions
>>>>>ullman at robustdecisions.com
>>>>>541-754-3609
>>>>>
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>>>>> 
>>>>
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