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  #21  
Old 06-25-2019, 10:16 AM
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DanH DanH is offline
 
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Location: 08A
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Quote:
Originally Posted by NovaBandit View Post
I think I was one of the first to put the AntiSplat cowl flaps in a 10 in lieu of the traditional louvers.

I battle a little with high CHTs, especially if I'm heat soaked... even in moderate temperatures. I absolutely have room for improvement on my baffling, and I'm hoping that will help a lot when I redo the baffling material, but the cowl flaps are not a magic bullet.
You got it. If the air is bypassing the hot parts, it contributes only drag. Exit area as big as a garbage can won't solve an underlying problem with poor heat transfer. Cold air in, only lukewarm out, and the engine stays hot.

It's why I ask folks to measure exit temperature.
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  #22  
Old 06-26-2019, 05:53 PM
rvdave rvdave is offline
 
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I have stock 8.5:1 io540 and feel I have tight baffling and rtvíd gaps . I struggled with whether to put in louvers based on others that have gone before and decided not to. Iím in Michigan but have flown in Florida with 90+ temps and am comfortable with my cylinder temps in cruise and simply donít climb as quick if temps get around 400 but usually thatís not a problem. Oil temps not an issue with butterfly valve which works well and can keep oil temps where I want them. I have dual ei and not sure if that makes a difference or not. Just more info to ponder.
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  #23  
Old 06-26-2019, 07:00 PM
Kyle Boatright Kyle Boatright is offline
 
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Location: Atlanta, GA
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Quote:
Originally Posted by falcon900guy View Post
i spent a day at jet guys out of covington, tn and owner shared a tip with me how to make a lip on aft exit of cowl, and also we put a half piece of pipe on bottom of firewall each side of cowl at the exhaust to create a low pressure sucking the hot air out.
I don't exactly follow you on this. Did you fair the lip on the firewall with that piece of pipe to get a smoother transition (and better exit velocity)?

Thanks,
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  #24  
Old 06-26-2019, 10:37 PM
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DanH DanH is offline
 
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Quote:
Originally Posted by falcon900guy View Post
i have some pictures to show what we did. don't know if this helps but there you have it
Kenny, you have my email. Send the pictures?
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  #25  
Old 06-26-2019, 11:03 PM
jpowell13 jpowell13 is offline
 
Join Date: Nov 2008
Location: Baton Rouge, LA
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Default Anti-splat Cowl Flap

I put one anti-splat cowl flap on the right side of my cowl because the #3 cylinder of my 6A's O320 runs hottest. One nice thing about Anti-splat is that it is very easy to install. I see a CHT reduction of about 5 degrees F when I open it in straight and level cruise.

I need to work on baffling to get more balanced CHTs but I'm glad I have the cowl flap for those real hot days. John
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  #26  
Old 06-26-2019, 11:52 PM
lr172 lr172 is online now
 
Join Date: Oct 2013
Location: Schaumburg, IL
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Quote:
Originally Posted by rvdave View Post
I have stock 8.5:1 io540 and feel I have tight baffling and rtvíd gaps . I struggled with whether to put in louvers based on others that have gone before and decided not to. Iím in Michigan but have flown in Florida with 90+ temps and am comfortable with my cylinder temps in cruise and simply donít climb as quick if temps get around 400 but usually thatís not a problem. Oil temps not an issue with butterfly valve which works well and can keep oil temps where I want them. I have dual ei and not sure if that makes a difference or not. Just more info to ponder.
Thanks for sharing.

Larry
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  #27  
Old 06-27-2019, 10:18 AM
greghale greghale is offline
 
Join Date: Jan 2006
Location: TULSA, OK
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I had the same problem in climb with CHT's (400) when I was in phase one. I used Nick Nafsinger's cowl flap design and added cowl flaps outboard of the cowling exit on the bottom. My temps dropped to 380 during climb and I was able to climb out at 110kts and 800-1000 fpm.
These cowl flaps were added after the -10 was painted. Very little touch up was needed.
I have drawings and pictures on my web site http://www.nwacaptain.com/cowl_flap.html if you are interested.
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  #28  
Old 07-18-2019, 01:06 PM
AviatorJ AviatorJ is offline
 
Join Date: Feb 2015
Location: Oklahoma City
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I've been battling with higher than desired CHTs (>400). At the time I only had two cowl flaps in the same location as the default RV-10 louvers. Typically my hot cylinders were 1,2,5,6. At times a few of these would push towards 440 on my earlier flights. Here were some of the steps I took which incrementally improved things.

- Ensured baffling material was flat, especially in the rear corners.
- RTV'd obvious openings.
- Did the 'washer trick' behind #5.
- Trimmed 1 & 2 baffle dams.

The above along with pulling power out faster, managing climb speed (125 knots) helped but I was still seeing 1,2 & 6 get into the 430s (5 was good) and I didn't really like reducing power so fast and it started to get hotter out which started to drive the temps back up. So next I-

- Went through a ton of RTV, putting it on every gap, between the cylinders, all over my hands, floor... it was a mess but hey it has to be sealed at this point right?
- I also replaced the outboard lower baffle rods with some ends I fabricated out of bolts and used hose covered safety wire to pull them in nice and tight.
- I shimmed the space behind #6 to ensure there was an adequate gap.
- A major improvement was fiber-glassing in the top cowl inlets especially around the prop governor.

This got me able to full power climb in about 80 OAT with 1&2 just a bit over 420... still high but easily manageable.

The latest, and the reasoning for me posting here, was the installation of stock louvers in the not stock area. I'm post paint so the idea of installing something that would botch that up didn't set well with me. I noticed Vans now sells a louver kit for the 7&9 which looked as if they could be replicated on the 10. So that's what I did, I installed two louvers in the bottom area on the most outboard part of the lower cowling.

Here are some pictures but all in all it took me maybe 10 hours, most of that being the fiberglass work. These louvers in conjunction with my cowl flaps open seemed to really improve airflow. Today 91 OAT, full power climb at 95 knots (was doing this on purpose) and the hottest cylinder was 410. My intent was to push it hard and see the results. I'm really happy with the results of the louvers. I look forward to sub 400 climb outs!







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  #29  
Old 07-18-2019, 01:17 PM
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Lynnb Lynnb is offline
 
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Looks good, did you buy and adapt the louvers from Van's or was this 100% roll your own?

Lynn
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  #30  
Old 07-18-2019, 01:20 PM
TShort TShort is offline
 
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Location: Indianapolis, IN (KUMP)
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Do you have data to compare cruise before / after?
Curious how it affects the top end.
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