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  #41  
Old 06-28-2018, 10:16 AM
rv7charlie rv7charlie is online now
 
Join Date: May 2006
Location: Pocahontas MS
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A thought from the scrounger gallery. If you're going to do heat shields as Dan mentions, you can use stainless instead of aluminum. Really thin stainless doesn't weigh much (if any) more than aluminum that's thick enough to be stable. Added advantage is less re-transmission of heat.

Now for the scrounger reference. Check the local Wally World or other discount chain for a cheap stainless 'stock pot'. It cuts & deburs easily with an abrasive cutoff wheel, and you can shape the pieces with your seaming pliers, vice, etc.
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  #42  
Old 07-09-2018, 08:08 PM
crabandy crabandy is offline
 
Join Date: Jan 2010
Location: Ottawa, Ks
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Quote:
Originally Posted by rv7charlie View Post
A thought from the scrounger gallery. If you're going to do heat shields as Dan mentions, you can use stainless instead of aluminum. Really thin stainless doesn't weigh much (if any) more than aluminum that's thick enough to be stable. Added advantage is less re-transmission of heat.

Now for the scrounger reference. Check the local Wally World or other discount chain for a cheap stainless 'stock pot'. It cuts & deburs easily with an abrasive cutoff wheel, and you can shape the pieces with your seaming pliers, vice, etc.
I like the tip, I've scrounged cutting boards and various layup shapes from Wally World numerous times.
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  #43  
Old 07-09-2018, 08:25 PM
crabandy crabandy is offline
 
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I had some scrap stainless, FiberFrax and foil tape so I went to work making a heat shield.

I used my roller a second time (only had it 3 years) to roll my over-sized piece of stainless and fit it over the exhaust.





I made some trim marks with a marker and scrap cardboard and went to work cutting out my piece with the die grinder. I like to use scrap angle as a cutting guide for straight lines, works well for filing too.





Heat Shield with the edges cleaned up.



I made and riveted some attachment brackets to the heat shield and covered the side opposite the exhaust pipe in Fiberfrax and aluminum tape.



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Last edited by crabandy : 07-09-2018 at 08:29 PM.
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  #44  
Old 07-09-2018, 08:37 PM
crabandy crabandy is offline
 
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Heat shield in place.









I don't have any "before" temp measurements, but will try to get a guesstimate based off the distance from the exhaust pipe. The opposite side has the standard vetterman crossover heat muff I suppose acts as a radiant heat shield as well.
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  #45  
Old 07-11-2018, 09:37 AM
crabandy crabandy is offline
 
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I placed my temp probe just in front of the fuel elbow on the carb.



I don't have any "before heat shield" temps, but this location by the carb/fuel line is 35-40*F hotter than the rest of the lower cowling. In cruise I was seeing 205*F with OAT's of 65*F. After a 30 min shutdown and taxi back to the runway with 86 *F OAT's the temp was 245. Only 2-3 seconds of engine stumbles right after the heat soaked engine start, aggressively leaning the mixture stopped the stumbling.
At the completion of the flight I left the airplane idling for an extra couple minutes at full rich with no stumbles. I need to fly in hotter temps and longer taxi times for further evaluation.
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