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  #1  
Old 09-03-2023, 03:10 PM
Gnvflyer Gnvflyer is offline
 
Join Date: Oct 2022
Location: Hawthorne
Posts: 38
Default Cowl exit air attach brackets

9A here with screws for the cowl lower attach points instead of hinges.

Finally figured out how the exit air attach brackets mount and am considering leaving it off. The cowl seems solid without it.

Has anyone left this assembly off, or is that a bad idea?
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Hawthorne, FL
RV6A- sold
RV9A- FWF, fiberglass
442TC reserved
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  #2  
Old 09-03-2023, 07:11 PM
Kyle Boatright Kyle Boatright is offline
 
Join Date: Aug 2005
Location: Atlanta, GA
Posts: 5,380
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Quote:
Originally Posted by Gnvflyer View Post
9A here with screws for the cowl lower attach points instead of hinges.

Finally figured out how the exit air attach brackets mount and am considering leaving it off. The cowl seems solid without it.

Has anyone left this assembly off, or is that a bad idea?
Exit air attach bracket? The thing that keeps the coal shovel from vibrating/flexing itself to death?
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Marietta, GA
2001 RV-6 N46KB
2019? (actually 2022) RV-10 N46BX
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  #3  
Old 09-03-2023, 07:59 PM
Gnvflyer Gnvflyer is offline
 
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Location: Hawthorne
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Quote:
Originally Posted by Kyle Boatright View Post
Exit air attach bracket? The thing that keeps the coal shovel from vibrating/flexing itself to death?
Yes, it seems it's purpose is too stabilize the bottom of the cowl somewhat in addition to giving you something to attach a small trim plate that covers the slot for the nose gear. Additionally, it captures the ends of the hinge pins if you go that route.

I don't know for sure, but the trim plate may contribute to directing cooling air.
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Hawthorne, FL
RV6A- sold
RV9A- FWF, fiberglass
442TC reserved
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  #4  
Old 09-03-2023, 08:00 PM
Kyle Boatright Kyle Boatright is offline
 
Join Date: Aug 2005
Location: Atlanta, GA
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Quote:
Originally Posted by Gnvflyer View Post
Yes, it seems it's purpose is too stabilize the bottom of the cowl somewhat in addition to giving you something to attach a small trim plate that covers the slot for the nose gear. Additionally, it captures the ends of the hinge pins if you go that route.

I don't know for sure, but the trim plate may contribute to directing cooling air.
Your call, but my sense is that you risk fatigue cracks in your cowl if you leave it off for long.
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Kyle Boatright
Marietta, GA
2001 RV-6 N46KB
2019? (actually 2022) RV-10 N46BX
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  #5  
Old 09-03-2023, 08:15 PM
rvbuilder2002 rvbuilder2002 is offline
 
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 10,339
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It might surprise you how much internal air pressure is pushing outward on that part of the cowl in high speed flight.
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Scott McDaniels
Hubbard, Oregon
Formerly of Van's Aircraft Engineering Prototype Shop
FAA/DAR, A&P, EAA Technical Councelor
RV-6A (aka "Junkyard Special ")
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  #6  
Old 09-03-2023, 11:26 PM
David Lewis David Lewis is offline
 
Join Date: Feb 2011
Location: Burbank, CA
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Buttoning up the bottom of my lower cowl noticeably contributed to lower engine temps. Air pushing up through the slot for the nose gear seemed to disrupt the proper flow of cooling air traveling down from the cylinders and out the chute. Once I had all the brackets and fairings in place to cover the slot, my CHTís dropped. The cowl exit attach bracket helps secure the bottom to ensure proper airflow.
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  #7  
Old 09-04-2023, 08:38 AM
Gnvflyer Gnvflyer is offline
 
Join Date: Oct 2022
Location: Hawthorne
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Quote:
Originally Posted by David Lewis View Post
Buttoning up the bottom of my lower cowl noticeably contributed to lower engine temps. Air pushing up through the slot for the nose gear seemed to disrupt the proper flow of cooling air traveling down from the cylinders and out the chute. Once I had all the brackets and fairings in place to cover the slot, my CHTís dropped. The cowl exit attach bracket helps secure the bottom to ensure proper airflow.
I suspected that might be the case. Based on feedback received here and from others, I'm going to go ahead and put it on.

Thanks for all the replies.
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Hawthorne, FL
RV6A- sold
RV9A- FWF, fiberglass
442TC reserved
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  #8  
Old 09-04-2023, 08:49 AM
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Jpm757 Jpm757 is offline
 
Join Date: May 2013
Location: Sherman, CT
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Good call!
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RV6 #20477 completed 1991 sold.
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