Matronics Email Lists :: View topic

Matronics Email Lists
Web Forum Interface to the Matronics Email Lists

Get Email Distribution Too! FAQ Search Memberlist Usergroups Register

Profile Log in to check your private messages Log in

Hottest Cyl CHT

Matronics Email Lists Forum Index -> RV10-List

View previous topic :: View next topic

Author Message

Deems Davis

Joined: 09 Jan 2006
Posts: 925

Posted: Wed Sep 29, 2010 10:15 am Post subject: Hottest Cyl CHT

What's your hottest       cylinder ?

       

       The reason I'm asking is that mine is #6, followed closely by #2 (at)       OSH I was asking around and it seemed that the same was true for       several others? During the summer which lasts a while here in AZ       (Today's high is 105) I need to pay attention to these during       climb as # 6 will easily top 410F and with a steep/long climb will       reach 420.

       

       My initial assumption is that #6 is loosing some cooling air to       the cylinders which is being sent to to the oil cooler. For those       of us with the plenum, it's probably compounded due to having the       oil air intake much lower and eclipsing the cylinder.

       

       I've been noodling about how to get more cooling air through #6       & #2, and would appreciate any thoughts/efforts that others       have done/attempted. I just finished installing some 'fixed cowl       flaps' on the bottom of the cowl similar to what Al Gardner did,       the theory being that it would increase the lower cowl exit area       and improve air flow from upper to lower cowl, but a test flight       yesterday didn't indicate much if any improvement.

       

       I've thought about cutting back the baffeling on #6 & #2 that       wrapped around the lower portion of the cylinder. I recall Sam       James saying that the Van's baffeling wasn't opened up enough.       Thoughts????

       

       

       Thanks

       

       Deems

            [quote][b]

jcumins(at)jcis.net
Guest

Posted: Wed Sep 29, 2010 10:39 am Post subject: Hottest Cyl CHT

Deems  

   

If you cut back the baffling make sure to do it on the top  of the cylinders and not the bottom side.  You need to increase the differential pressure between the top of the engine and the bottom.  I have see several people trim back the front plate on the #2 cylinder but since you have the fancy cowl I am not too sure how to help you on that one.  On our Saratoga we have both oil coolers on the aft baffling right next to the #5 and # 6 cylinders and the engine stays nice and cool here in our 105 degree heat in northern California.  So I do not think it is the oil cooler air outlet causing the issues.  

   

I would be looking at getting the max air in the top of the engine and then making sure there is not blockage or reverse pressure on the bottom of the engine.  

   

If you have access to a couple of gauges it would be worth the trouble to do some pressure checks to determine the differential pressure in the cowl that will answer a lot of questions and take some guess work out of it.  

   

John Cumins 40864  

Emp done reorganizing garage for Wings  

   

       

From: owner-rv10-list-server(at)matronics.com [mailto:owner-rv10-list-server(at)matronics.com] On Behalf Of Deems Davis

 Sent: Wednesday, September 29, 2010 11:12 AM

 To: rv10-list(at)matronics.com

 Subject: Hottest Cyl CHT  

  

  

   

What's your hottest cylinder ?

 

 The reason I'm asking is that mine is #6, followed closely by #2 (at) OSH I was asking around and it seemed that the same was true for several others? During the summer which lasts a while here in AZ (Today's high is 105) I need to pay attention to these during climb as # 6 will easily top 410F and with a steep/long climb will reach 420.

 

 My initial assumption is that #6 is loosing some cooling air to the cylinders which is being sent to to the oil cooler. For those of us with the plenum, it's probably compounded due to having the oil air intake much lower and eclipsing the cylinder.

 

 I've been noodling about how to get more cooling air through #6 & #2, and would appreciate any thoughts/efforts that others have done/attempted. I just finished installing some 'fixed cowl flaps' on the bottom of the cowl similar to what Al Gardner did, the theory being that it would increase the lower cowl exit area and improve air flow from upper to lower cowl, but a test flight yesterday didn't indicate much if any improvement.

 

 I've thought about cutting back the baffeling on #6 & #2 that wrapped around the lower portion of the cylinder. I recall Sam James saying that the Van's baffeling wasn't opened up enough. Thoughts????

 

 

 Thanks

 

 Deems   	  Quote: 	
		    	
[/b][/quote]http://forums.matronics.com[/url]         - List Contribution Web generous nbsp;                        --> http://www.matronics.com/c=[/b] [b]

dlm46007(at)cox.net
Guest

Posted: Wed Sep 29, 2010 10:51 am Post subject: Hottest Cyl CHT

I have completely removed the air dams on cyls 1  and 2. CHTs rarely get above 360 and it is usually 6 and 2. I never see above  400; only seen during break-in.

 [quote]   ---

BPA(at)bpaengines.com
Guest

Posted: Wed Sep 29, 2010 11:04 am Post subject: Hottest Cyl CHT

Deems,  

   

410F on climb out is not IMO considered high, even 420 isn’t out of the norm on a ‘steep/ long climb, but getting warm.   

   

What are the other 4 cylinders’ CHT during normal climb out/, steep/ long climbs?  

   

   

Allen  

   

-----Original Message-----

 From: owner-rv10-list-server(at)matronics.com [mailto:owner-rv10-list-server(at)matronics.com] On Behalf Of Deems Davis

 Sent: Wednesday, September 29, 2010 12:12 PM

 To: rv10-list(at)matronics.com

 Subject: Hottest Cyl CHT  

   

What's your hottest cylinder ?

 

 The reason I'm asking is that mine is #6, followed closely by #2 (at) OSH I was asking around and it seemed that the same was true for several others? During the summer which lasts a while here in AZ (Today's high is 105) I need to pay attention to these during climb as # 6 will easily top 410F and with a steep/long climb will reach 420.

 

 My initial assumption is that #6 is loosing some cooling air to the cylinders which is being sent to to the oil cooler. For those of us with the plenum, it's probably compounded due to having the oil air intake much lower and eclipsing the cylinder.

 

 I've been noodling about how to get more cooling air through #6 & #2, and would appreciate any thoughts/efforts that others have done/attempted. I just finished installing some 'fixed cowl flaps' on the bottom of the cowl similar to what Al Gardner did, the theory being that it would increase the lower cowl exit area and improve air flow from upper to lower cowl, but a test flight yesterday didn't indicate much if any improvement.

 

 I've thought about cutting back the baffeling on #6 & #2 that wrapped around the lower portion of the cylinder. I recall Sam James saying that the Van's baffeling wasn't opened up enough. Thoughts????

 

 

 Thanks

 

 Deems  [quote]  http://www.matronics.com/Navigator?RV10-Listhttp://forums.matronics.comhttp://www.matronics.com/contribution [b]

pitts_pilot(at)bellsouth.
Guest

Posted: Wed Sep 29, 2010 11:50 am Post subject: Hottest Cyl CHT

Having had nightmares about high oil temps (I live in FL), I've     taken a good look at the oil cooler installation ..... and here's my     thoughts:

     1:  The oil cooler plenum is poor at best .... the incoming air     (from the baffle) only hits about 1/3 of the cooler directly, and     turbulent air at that.  Some kind of baffle inside the plenum should     help direct some of the air to the top part of the cooler.

     

     2:  The outlet air of the cooler dumps into the corner of the lower     cowl, and I suspect there's not too much flow in that area.  The     differential pressure from upper to lower cowl determines how much     air flow is available for the cooler.  Subtract the drag caused by     the oil cooler itself, and now the differential pressure is even     less.  It would seem that an outlet plenum with scat hose connected     to louvers on the bottom of the cowl would create a lower pressure     area and would enhance the airflow through the cooler.

     

     someone tell me where I'm fooling myself here!!!

     Linn

     do not archive

     On 9/29/2010 2:34 PM, John Cumins wrote:     [quote]                          <![endif]-->       <![endif]-->                

Deems         

          

If you cut back the baffling make sure to do it             on the top              of the cylinders and not the bottom side.  You need to             increase the differential             pressure between the top of the engine and the bottom.  I             have see several             people trim back the front plate on the #2 cylinder but             since you have the             fancy cowl I am not too sure how to help you on that one.              On our Saratoga             we have both oil coolers on the aft baffling right next to             the #5 and # 6             cylinders and the engine stays nice and cool here in our 105             degree heat in             northern California.  So I do not think it is the oil cooler             air outlet             causing the issues.         

          

I would be looking at getting the max air in the             top of the             engine and then making sure there is not blockage or reverse             pressure on the             bottom of the engine.         

          

If you have access to a couple of gauges it would             be worth the             trouble to do some pressure checks to determine the             differential pressure in             the cowl that will answer a lot of questions and take some             guess work out of             it.         

          

John Cumins 40864         

Emp done reorganizing garage for Wings         

          

                                  

From: owner-rv10-list-server(at)matronics.com (owner-rv10-list-server(at)matronics.com)                 [mailto:owner-rv10-list-server(at)matronics.com (owner-rv10-list-server(at)matronics.com)] On                   Behalf Of Deems Davis

                 Sent: Wednesday, September 29, 2010 11:12 AM

                 To: rv10-list(at)matronics.com (rv10-list(at)matronics.com)

                 Subject: Hottest Cyl CHT           

         

         

          

What's             your hottest cylinder ?

             

             The reason I'm asking is that mine is #6, followed closely             by #2 (at) OSH I was             asking around and it seemed that the same was true for             several others? During             the summer which lasts a while here in AZ (Today's high is             105) I need to pay             attention to these during climb as # 6 will easily top 410F             and with a             steep/long climb will reach 420.

             

             My initial assumption is that #6 is loosing some cooling air             to the cylinders             which is being sent to to the oil cooler. For those of us             with the plenum, it's             probably compounded due to having the oil air intake much             lower and eclipsing             the cylinder.

             

             I've been noodling about how to get more cooling air through             #6 & #2, and             would appreciate any thoughts/efforts that others have             done/attempted. I just             finished installing some 'fixed cowl flaps' on the bottom of             the cowl similar             to what Al Gardner did, the theory being that it would             increase the lower cowl             exit area and improve air flow from upper to lower cowl, but             a test flight             yesterday didn't indicate much if any improvement.

             

             I've thought about cutting back the baffeling on #6 & #2             that wrapped             around the lower portion of the cylinder. I recall Sam James             saying that the             Van's baffeling wasn't opened up enough. Thoughts????

             

             

             Thanks

             

             Deems          	  Quote: 	
		    	
         http://www.matronic=================http://forums.matronics.com                     - List Contribution Web generous             nbsp;                        --> http://www.matronics.com/c=              	  Quote: 	
		   	
           

        	  Quote: 	
		  

	
     [b]

speckter(at)comcast.net
Guest

Posted: Wed Sep 29, 2010 11:54 am Post subject: Hottest Cyl CHT

Alan, I was told that the metallurgy starts changing at about 420 degrees and getting the CHT up that high is bad.  You obviously aren’t concerned.  Why are others concerned and not you?  

   

Gary Specketer  

         

  

From: owner-rv10-list-server(at)matronics.com [mailto:owner-rv10-list-server(at)matronics.com] On Behalf Of BPA

 Sent: Wednesday, September 29, 2010 3:06 PM

 To: rv10-list(at)matronics.com

 Subject: RE: Hottest Cyl CHT  

  

   

Deems,  

   

410F on climb out is not IMO considered high, even 420 isn’t out of the norm on a ‘steep/ long climb, but getting warm.   

   

What are the other 4 cylinders’ CHT during normal climb out/, steep/ long climbs?  

   

   

Allen  

   

-----Original Message-----

 From: owner-rv10-list-server(at)matronics.com [mailto:owner-rv10-list-server(at)matronics.com] On Behalf Of Deems Davis

 Sent: Wednesday, September 29, 2010 12:12 PM

 To: rv10-list(at)matronics.com

 Subject: Hottest Cyl CHT  

   

What's your hottest cylinder ?

 

 The reason I'm asking is that mine is #6, followed closely by #2 (at) OSH I was asking around and it seemed that the same was true for several others? During the summer which lasts a while here in AZ (Today's high is 105) I need to pay attention to these during climb as # 6 will easily top 410F and with a steep/long climb will reach 420.

 

 My initial assumption is that #6 is loosing some cooling air to the cylinders which is being sent to to the oil cooler. For those of us with the plenum, it's probably compounded due to having the oil air intake much lower and eclipsing the cylinder.

 

 I've been noodling about how to get more cooling air through #6 & #2, and would appreciate any thoughts/efforts that others have done/attempted. I just finished installing some 'fixed cowl flaps' on the bottom of the cowl similar to what Al Gardner did, the theory being that it would increase the lower cowl exit area and improve air flow from upper to lower cowl, but a test flight yesterday didn't indicate much if any improvement.

 

 I've thought about cutting back the baffeling on #6 & #2 that wrapped around the lower portion of the cylinder. I recall Sam James saying that the Van's baffeling wasn't opened up enough. Thoughts????

 

 

 Thanks

 

 Deems   	  Quote: 	
		    http://www.matronics.com/Navigator?RV10-Listhttp://forums.matronics.comhttp://www.matronics.com/contribution         http://www.matronics.com/Navigator?RV10-Listhttp://forums.matronics.comhttp://www.matronics.com/contribution 	


        [quote][b]

scottmschmidt(at)yahoo.co
Guest

Posted: Wed Sep 29, 2010 12:11 pm Post subject: Hottest Cyl CHT

#2 for me. 

-Scott Schmidt



Sent from my iPhone



On Sep 29, 2010, at 1:06 PM, "BPA" <BPA(at)bpaengines.com (BPA(at)bpaengines.com)> wrote:



 	  Quote: 	
		       

Deems,  

   

410F on climb out is not IMO considered high, even 420 isnâ€™t out of the norm on a â€˜steep/ long climb, but getting warm.   

   

What are the other 4 cylindersâ€™ CHT during normal climb out/, steep/ long climbs?  

   

   

Allen  

   

-----Original Message-----

 From: owner-rv10-list-server(at)matronics.com (owner-rv10-list-server(at)matronics.com) [mailto:owner-rv10-list-server(at)matronics.com] On Behalf Of Deems Davis

 Sent: Wednesday, September 29, 2010 12:12 PM

 To: [url=mailto:rv10-list(at)matronics.com]rv10-list(at)matronics.com (rv10-list(at)matronics.com)[/url]

 Subject: Hottest Cyl CHT  

   

What's your hottest cylinder ?

 

 The reason I'm asking is that mine is #6, followed closely by #2 (at) OSH I was asking around and it seemed that the same was true for several others? During the summer which lasts a while here in AZ (Today's high is 105) I need to pay attention to these during climb as # 6 will easily top 410F and with a steep/long climb will reach 420.

 

 My initial assumption is that #6 is loosing some cooling air to the cylinders which is being sent to to the oil cooler. For those of us with the plenum, it's probably compounded due to having the oil air intake much lower and eclipsing the cylinder.

 

 I've been noodling about how to get more cooling air through #6 & #2, and would appreciate any thoughts/efforts that others have done/attempted. I just finished installing some 'fixed cowl flaps' on the bottom of the cowl similar to what Al Gardner did, the theory being that it would increase the lower cowl exit area and improve air flow from upper to lower cowl, but a test flight yesterday didn't indicate much if any improvement.

 

 I've thought about cutting back the baffeling on #6 & #2 that wrapped around the lower portion of the cylinder. I recall Sam James saying that the Van's baffeling wasn't opened up enough. Thoughts????

 

 

 Thanks

 

 Deems   	  Quote: 	
		     	  Quote: 	
		  [b]http://www.matronics.com/Navigator?RV10-List 	  Quote: 	
		  [b] 	
0 	  Quote: 	
		   	
1 	  Quote: 	
		   	
2 	  Quote: 	
		   	
3 	  Quote: 	
		   	
4 	  Quote: 	
		   	
5 	  Quote: 	
		   	
6 	  Quote: 	
		   	
7 	  Quote: 	
		   	
8 	  Quote: 	
		   	
9[/b] 	
[/b] 	
[/b] 	
[/b][/quote]

[b][b][b]       	  Quote: 	
		  [b] 	
0[/b][/b][/b][/b]

[/quote]

BPA(at)bpaengines.com
Guest

Posted: Wed Sep 29, 2010 12:35 pm Post subject: Hottest Cyl CHT

Gary, I’m not saying its good for them. I AM concerned at 420 if the CHT’s are run there for long periods of time, but not necessarily if only occasionally. Ideally, the best temps to run the cylinders are between 350-380. This will give you best cylinder life. I have seen cylinders that have been run in the low 430’s on aerobatic engines that have shown no noticeable effects. But then, I haven’t done any fatigue analysis on them either.   

   

Allen    

   

-----Original Message-----

 From: owner-rv10-list-server(at)matronics.com [mailto:owner-rv10-list-server(at)matronics.com] On Behalf Of gary

 Sent: Wednesday, September 29, 2010 1:52 PM

 To: rv10-list(at)matronics.com

 Subject: RE: Hottest Cyl CHT  

   

Alan, I was told that the metallurgy starts changing at about 420 degrees and getting the CHT up that high is bad.  You obviously aren’t concerned.  Why are others concerned and not you?  

   

Gary Specketer  

         

  

From: owner-rv10-list-server(at)matronics.com [mailto:owner-rv10-list-server(at)matronics.com] On Behalf Of BPA

 Sent: Wednesday, September 29, 2010 3:06 PM

 To: rv10-list(at)matronics.com

 Subject: RE: Hottest Cyl CHT  

  

   

Deems,  

   

410F on climb out is not IMO considered high, even 420 isn’t out of the norm on a ‘steep/ long climb, but getting warm.   

   

What are the other 4 cylinders’ CHT during normal climb out/, steep/ long climbs?  

   

   

Allen  

   

-----Original Message-----

 From: owner-rv10-list-server(at)matronics.com [mailto:owner-rv10-list-server(at)matronics.com] On Behalf Of Deems Davis

 Sent: Wednesday, September 29, 2010 12:12 PM

 To: rv10-list(at)matronics.com

 Subject: Hottest Cyl CHT  

   

What's your hottest cylinder ?

 

 The reason I'm asking is that mine is #6, followed closely by #2 (at) OSH I was asking around and it seemed that the same was true for several others? During the summer which lasts a while here in AZ (Today's high is 105) I need to pay attention to these during climb as # 6 will easily top 410F and with a steep/long climb will reach 420.

 

 My initial assumption is that #6 is loosing some cooling air to the cylinders which is being sent to to the oil cooler. For those of us with the plenum, it's probably compounded due to having the oil air intake much lower and eclipsing the cylinder.

 

 I've been noodling about how to get more cooling air through #6 & #2, and would appreciate any thoughts/efforts that others have done/attempted. I just finished installing some 'fixed cowl flaps' on the bottom of the cowl similar to what Al Gardner did, the theory being that it would increase the lower cowl exit area and improve air flow from upper to lower cowl, but a test flight yesterday didn't indicate much if any improvement.

 

 I've thought about cutting back the baffeling on #6 & #2 that wrapped around the lower portion of the cylinder. I recall Sam James saying that the Van's baffeling wasn't opened up enough. Thoughts????

 

 

 Thanks

 

 Deems   	  Quote: 	
		    http://www.matronics.com/Navigator?RV10-List 	
 	  Quote: 	
		  http://forums.matronics.com 	
 	  Quote: 	
		  http://www.matronics.com/contribution 	
 	  Quote: 	
		           http://www.matronics.com/Navigator?RV10-List 	
 	  Quote: 	
		  http://forums.matronics.com 	
 	  Quote: 	
		  http://www.matronics.com/contribution 	
 	  Quote: 	
		   	
 	  Quote: 	
		   	
 	  Quote: 	
		   http://www.matronics.com/Navigator?RV10-Listhttp://forums.matronics.comhttp://www.matronics.com/contribution 	


      [quote][b]

rv10builder(at)verizon.ne
Guest

Posted: Wed Sep 29, 2010 1:26 pm Post subject: Hottest Cyl CHT

concerning #1 if I understand you correctly- Tim made  mention of it on his website and commented that is was worse having the splitter  in the plenum than before he added it.

   From: Linn Walters (pitts_pilot(at)bellsouth.net) 

 Sent: Wednesday, September 29, 2010 12:46 PM

 To: rv10-list(at)matronics.com (rv10-list(at)matronics.com) 

 Subject: Re: Hottest Cyl CHT

Having had nightmares about high oil temps (I live in FL), I've  taken a good look at the oil cooler installation ..... and here's my  thoughts:

1:  The oil cooler plenum is poor at best .... the incoming  air (from the baffle) only hits about 1/3 of the cooler directly, and turbulent  air at that.  Some kind of baffle inside the plenum should help direct some  of the air to the top part of the cooler.

2:  The outlet air of the  cooler dumps into the corner of the lower cowl, and I suspect there's not too  much flow in that area.  The differential pressure from upper to lower cowl  determines how much air flow is available for the cooler.  Subtract the  drag caused by the oil cooler itself, and now the differential pressure is even  less.  It would seem that an outlet plenum with scat hose connected to  louvers on the bottom of the cowl would create a lower pressure area and would  enhance the airflow through the cooler.

someone tell me where I'm fooling  myself here!!!

Linn

do not archive

On 9/29/2010 2:34 PM, John Cumins  wrote:  [quote]               

Deems   

If    you cut back the baffling make sure to do it on the top  of the cylinders    and not the bottom side.  You need to increase the differential pressure    between the top of the engine and the bottom.  I have see several people    trim back the front plate on the #2 cylinder but since you have the fancy cowl    I am not too sure how to help you on that one.  On our Saratoga we have    both oil coolers on the aft baffling right next to the #5 and # 6 cylinders    and the engine stays nice and cool here in our 105 degree heat in northern    California.  So I do not think it is the oil cooler air outlet causing    the issues.   

I    would be looking at getting the max air in the top of the engine and then    making sure there is not blockage or reverse pressure on the bottom of the    engine.   

If    you have access to a couple of gauges it would be worth the trouble to do some    pressure checks to determine the differential pressure in the cowl that will    answer a lot of questions and take some guess work out of    it.   

John    Cumins 40864   

Emp    done reorganizing garage for Wings   

From:    owner-rv10-list-server(at)matronics.com (owner-rv10-list-server(at)matronics.com)    [mailto:owner-rv10-list-server(at)matronics.com (owner-rv10-list-server(at)matronics.com)]    On Behalf Of Deems Davis

Sent: Wednesday, September 29, 2010    11:12 AM

To: rv10-list(at)matronics.com (rv10-list(at)matronics.com)

Subject:    Hottest Cyl CHT

What's    your hottest cylinder ?

The reason I'm asking is that mine is #6,    followed closely by #2 (at) OSH I was asking around and it seemed that the same    was true for several others? During the summer which lasts a while here in AZ    (Today's high is 105) I need to pay attention to these during climb as # 6    will easily top 410F and with a steep/long climb will reach 420.

My    initial assumption is that #6 is loosing some cooling air to the cylinders    which is being sent to to the oil cooler. For those of us with the plenum,    it's probably compounded due to having the oil air intake much lower and    eclipsing the cylinder.

I've been noodling about how to get more    cooling air through #6 & #2, and would appreciate any thoughts/efforts    that others have done/attempted. I just finished installing some 'fixed cowl    flaps' on the bottom of the cowl similar to what Al Gardner did, the theory    being that it would increase the lower cowl exit area and improve air flow    from upper to lower cowl, but a test flight yesterday didn't indicate much if    any improvement.

I've thought about cutting back the baffeling on #6    & #2 that wrapped around the lower portion of the cylinder. I recall Sam    James saying that the Van's baffeling wasn't opened up enough.    Thoughts????

Thanks

Deems 	  Quote: 	

http://www.matronic=================http://forums.matronics.com            - List Contribution Web generous    nbsp;                           --> http://www.matronics.com/c=  	  Quote: 	

 	  Quote: 	

href="http://www.matronics.com/Navigator?RV10-List">http://www.matronics.com/Navigator?RV10-List

href="http://forums.matronics.com">http://forums.matronics.com

href="http://www.matronics.com/contribution">http://www.matronics.com/c

[b]

pitts_pilot(at)bellsouth.
Guest

Posted: Wed Sep 29, 2010 1:50 pm Post subject: Hottest Cyl CHT

Thanks Pascal .... I looked at Tim's site and that was what I was     contemplating.  +5 degrees could be anything from time of year to     phase of moon.  Thanks for the heads up.  Anyone else have data???      Might forget #1.

     Linn

     

     On 9/29/2010 5:20 PM, Pascal wrote:     [quote]                            concerning #1 if I understand you           correctly- Tim made mention of it on his website and commented           that is was worse having the splitter in the plenum than           before he added it.

       

                           From: Linn Walters (pitts_pilot(at)bellsouth.net) 

           Sent: Wednesday, September 29, 2010 12:46 PM

           To: rv10-list(at)matronics.com (rv10-list(at)matronics.com)           

           Subject: Re: Hottest Cyl CHT

         

       

       

       

       Having had nightmares about high oil temps (I live in FL), I've       taken a good look at the oil cooler installation ..... and here's       my thoughts:

       1:  The oil cooler plenum is poor at best .... the incoming air       (from the baffle) only hits about 1/3 of the cooler directly, and       turbulent air at that.  Some kind of baffle inside the plenum       should help direct some of the air to the top part of the cooler.

       

       2:  The outlet air of the cooler dumps into the corner of the       lower cowl, and I suspect there's not too much flow in that area.        The differential pressure from upper to lower cowl determines how       much air flow is available for the cooler.  Subtract the drag       caused by the oil cooler itself, and now the differential pressure       is even less.  It would seem that an outlet plenum with scat hose       connected to louvers on the bottom of the cowl would create a       lower pressure area and would enhance the airflow through the       cooler.

       

       someone tell me where I'm fooling myself here!!!

       Linn

       do not archive

       On 9/29/2010 2:34 PM, John Cumins wrote:        	  Quote: 	
		                                          

Deems           

            

If you cut back the baffling make sure               to do it on the top  of the cylinders and not the bottom               side.  You need to increase the differential pressure               between the top of the engine and the bottom.  I have see               several people trim back the front plate on the #2               cylinder but since you have the fancy cowl I am not too               sure how to help you on that one.  On our Saratoga we have               both oil coolers on the aft baffling right next to the #5               and # 6 cylinders and the engine stays nice and cool here               in our 105 degree heat in northern California.  So I do               not think it is the oil cooler air outlet causing the               issues.           

            

I would be looking at getting the max               air in the top of the engine and then making sure there is               not blockage or reverse pressure on the bottom of the               engine.           

            

If you have access to a couple of gauges               it would be worth the trouble to do some pressure checks               to determine the differential pressure in the cowl that               will answer a lot of questions and take some guess work               out of it.           

            

John Cumins 40864           

Emp done reorganizing garage for Wings           

            

                                        

From: owner-rv10-list-server(at)matronics.com (owner-rv10-list-server(at)matronics.com)                   [mailto:owner-rv10-list-server(at)matronics.com (owner-rv10-list-server(at)matronics.com)]                   On Behalf Of Deems Davis

                   Sent: Wednesday, September 29, 2010 11:12 AM

                   To: rv10-list(at)matronics.com (rv10-list(at)matronics.com)

                   Subject: Hottest Cyl CHT             

           

           

            

What's your hottest cylinder ?

               

               The reason I'm asking is that mine is #6, followed closely               by #2 (at) OSH I was asking around and it seemed that the               same was true for several others? During the summer which               lasts a while here in AZ (Today's high is 105) I need to               pay attention to these during climb as # 6 will easily top               410F and with a steep/long climb will reach 420.

               

               My initial assumption is that #6 is loosing some cooling               air to the cylinders which is being sent to to the oil               cooler. For those of us with the plenum, it's probably               compounded due to having the oil air intake much lower and               eclipsing the cylinder.

               

               I've been noodling about how to get more cooling air               through #6 & #2, and would appreciate any               thoughts/efforts that others have done/attempted. I just               finished installing some 'fixed cowl flaps' on the bottom               of the cowl similar to what Al Gardner did, the theory               being that it would increase the lower cowl exit area and               improve air flow from upper to lower cowl, but a test               flight yesterday didn't indicate much if any improvement.

               

               I've thought about cutting back the baffeling on #6 &               #2 that wrapped around the lower portion of the cylinder.               I recall Sam James saying that the Van's baffeling wasn't               opened up enough. Thoughts????

               

               

               Thanks

               

               Deems            	  Quote: 	
		    	
           http://www.matronic=================http://forums.matronics.com                       - List Contribution Web generous               nbsp;                        --> http://www.matronics.com/c=                	  Quote: 	
		   	
             

          	  Quote: 	
		  

	
       	
       

               	  Quote: 	
		  



href="http://www.matronics.com/Navigator?RV10-List">http://www.matronics.com/Navigator?RV10-List

href="http://forums.matronics.com">http://forums.matronics.com

href="http://www.matronics.com/contribution">http://www.matronics.com/c



	
     [b]

partner14

Joined: 12 Jan 2008
Posts: 540
Location: Granbury Texas

Posted: Wed Sep 29, 2010 1:52 pm Post subject: Hottest Cyl CHT

I'm not sure he actually said it was worse... but maybe not noticeably better.

 Don



--- On Wed, 9/29/10, Pascal <rv10builder(at)verizon.net> wrote:



  	  Quote: 	
		  

From: Pascal <rv10builder(at)verizon.net>

Subject: Re: Hottest Cyl CHT

To: rv10-list(at)matronics.com

Date: Wednesday, September 29, 2010, 2:20 PM



  concerning #1 if I understand you correctly- Tim made mention of it on his website and commented that is was worse having the splitter in the plenum than before he added it.



   From: Linn Walters (pitts_pilot(at)bellsouth.net) 

 Sent: Wednesday, September 29, 2010 12:46 PM

 To: rv10-list(at)matronics.com (rv10-list(at)matronics.com) 

 Subject: Re: Hottest Cyl CHT

 



Having had nightmares about high oil temps (I live in FL), I've taken a good look at the oil cooler installation ..... and here's my thoughts:

1:  The oil cooler plenum is poor at best .... the incoming air (from the baffle) only hits about 1/3 of the cooler directly, and turbulent air at that.  Some kind of baffle inside the plenum should help direct some of the air to the top part of the cooler.



2:  The outlet air of the cooler dumps into the corner of the lower cowl, and I suspect there's not too much flow in that area.  The differential pressure from upper to lower cowl determines how much air flow is available for the cooler.  Subtract the drag caused by the oil cooler itself, and now the differential pressure is even less.  It would seem that an outlet plenum with scat hose connected to louvers on the bottom of the cowl would create a lower pressure area and would enhance the airflow through  the cooler.



someone tell me where I'm fooling myself here!!!

Linn

do not archive

On 9/29/2010 2:34 PM, John Cumins wrote:   	  Quote: 	
		        

Deems

 

 

 

If you cut back the baffling make sure to do it on the top  of the cylinders and not the bottom side.  You need to increase the differential pressure between the top of the engine and the bottom.  I have see several people trim back the front plate on the #2 cylinder but since you have the fancy cowl I am not too sure how to help you on that one.  On our Saratoga we have both oil coolers on the aft baffling right next to the #5 and # 6 cylinders and the engine stays nice and cool here in our 105 degree heat in northern California.  So I do not think it is the oil cooler air outlet causing the issues.

 

 

 

I would be looking at getting the max air in the top of the engine and then making sure there is not blockage or reverse pressure on the bottom of the engine.

 

 

 

If you have access to a couple of gauges it would be worth the trouble to do some pressure checks to determine the differential pressure in the cowl that will answer a lot of questions and take some guess work out of it.

 

 

 

John Cumins 40864

 

Emp done reorganizing garage for Wings

 

 

 

 

   

From: owner-rv10-list-server(at)matronics.com (owner-rv10-list-server(at)matronics.com) [mailto:owner-rv10-list-server(at)matronics.com (owner-rv10-list-server(at)matronics.com)] On Behalf Of Deems Davis

Sent: Wednesday, September 29,  2010 11:12 AM

To: rv10-list(at)matronics.com (rv10-list(at)matronics.com)

Subject: Hottest Cyl CHT

 

 

 

What's your hottest cylinder ?



The reason I'm asking is that mine is #6, followed closely by #2 (at) OSH I was asking around and it seemed that the same was true for several others? During the summer which lasts a while here in AZ (Today's high is 105) I need to pay attention to these during climb as # 6 will easily top 410F and with a steep/long climb will reach 420.



My initial assumption is that #6 is loosing some cooling air to the cylinders which is being sent to to the oil cooler. For those of us with the plenum, it's probably compounded due to having the oil air intake much lower and eclipsing the cylinder.



I've been noodling about how to get more cooling air through #6 & #2, and would appreciate any thoughts/efforts that others have done/attempted. I just finished installing some 'fixed cowl flaps' on the bottom of the cowl similar to what Al Gardner did,  the theory being that it would increase the lower cowl exit area and improve air flow from upper to lower cowl, but a test flight yesterday didn't indicate much if any improvement.



I've thought about cutting back the baffeling on #6 & #2 that wrapped around the lower portion of the cylinder. I recall Sam James saying that the Van's baffeling wasn't opened up enough. Thoughts????

Thanks



Deems

 	  Quote: 	
		      	
http://www.matronic================= http://forums.matronics.com          - List Contribution Web generous nbsp;                        --> http://www.matronics.com/c=  	  Quote: 	
		    

	




href="http://www.matronics.com/Navigator?RV10-List">http://www.matronics.com/Navigator?RV10-List

href="http://forums.matronics.com">http://forums.matronics.com

href="http://www.matronics.com/contribution">http://www.matronics.com/c





=nofollow target=_blank>http://www.matronics.com/Navigator?RV10-List

et=_blank>http://forums.matronics.com

llow target=_blank>http://www.matronics.com/contribution



	


	


         [quote][b]

_________________
Don A. McDonald
40636

Ron.McGann(at)ausawd.com
Guest

Posted: Wed Sep 29, 2010 2:13 pm Post subject: Hottest Cyl CHT

#2 - even after trimming the dam to 1/2  size.

  

 cheers

 Ron

 VH-XRM flying in Oz



   From: owner-rv10-list-server(at)matronics.com  [mailto:owner-rv10-list-server(at)matronics.com] On Behalf Of Deems  Davis

Sent: Thursday, 30 September 2010 4:12 AM

To:  rv10-list(at)matronics.com

Subject: Hottest Cyl  CHT

 

What's your hottest  cylinder ?



The reason I'm asking is that mine is #6, followed closely by  #2 (at) OSH I was asking around and it seemed that the same was true for several  others? During the summer which lasts a while here in AZ (Today's high is 105) I  need to pay attention to these during climb as # 6 will easily top 410F and with  a steep/long climb will reach 420.



My initial assumption is that #6 is  loosing some cooling air to the cylinders which is being sent to to the oil  cooler. For those of us with the plenum, it's probably compounded due to having  the oil air intake much lower and eclipsing the cylinder.



I've been  noodling about how to get more cooling air through #6 & #2, and would  appreciate any thoughts/efforts that others have done/attempted. I just finished  installing some 'fixed cowl flaps' on the bottom of the cowl similar to what Al  Gardner did, the theory being that it would increase the lower cowl exit area  and improve air flow from upper to lower cowl, but a test flight yesterday  didn't indicate much if any improvement.



I've thought about cutting back  the baffeling on #6 & #2 that wrapped around the lower portion of the  cylinder. I recall Sam James saying that the Van's baffeling wasn't opened up  enough. Thoughts????

Thanks



Deems

[quote]



p://www.matronics.com/Navigator?RV10-List

ics.com

.matronics.com/contribution



[b]

Tim Olson

Joined: 25 Jan 2007
Posts: 2879

Posted: Wed Sep 29, 2010 2:21 pm Post subject: Hottest Cyl CHT

It wasn't consistent.  It seemed to be about the same initially, but over time I started to suspect it was slightly higher.  Whatever the case I don't think it was a very significant change.  It may be one of those things that works better or worse for you depending on other factors, so it may be worthwhile, and I like the theory behind it, but I removed mine now and things are no worse and maybe slightly better for me on climbout.

So it's hard to say for sure.

Tim





On Sep 29, 2010, at 4:49 PM, Don McDonald <building_partner(at)yahoo.com (building_partner(at)yahoo.com)> wrote:



[quote]I'm not sure he actually said it was worse... but maybe not noticeably better.

 Don



--- On Wed, 9/29/10, Pascal <rv10builder(at)verizon.net (rv10builder(at)verizon.net)> wrote:



  	  Quote: 	
		  

From: Pascal <rv10builder(at)verizon.net (rv10builder(at)verizon.net)>

Subject: Re: Hottest Cyl CHT

To: [url=mailto:rv10-list(at)matronics.com]rv10-list(at)matronics.com (rv10-list(at)matronics.com)[/url]

Date: Wednesday, September 29, 2010, 2:20 PM



  concerning #1 if I understand you correctly- Tim made mention of it on his website and commented that is was worse having the splitter in the plenum than before he added it.



   From: Linn Walters (pitts_pilot(at)bellsouth.net) 

 Sent: Wednesday, September 29, 2010 12:46 PM

 To: [url=mailto:rv10-list(at)matronics.com]rv10-list(at)matronics.com (rv10-list(at)matronics.com)[/url] 

 Subject: Re: Hottest Cyl CHT

 



Having had nightmares about high oil temps (I live in FL), I've taken a good look at the oil cooler installation ..... and here's my thoughts:

1:  The oil cooler plenum is poor at best .... the incoming air (from the baffle) only hits about 1/3 of the cooler directly, and turbulent air at that.  Some kind of baffle inside the plenum should help direct some of the air to the top part of the cooler.



2:  The outlet air of the cooler dumps into the corner of the lower cowl, and I suspect there's not too much flow in that area.  The differential pressure from upper to lower cowl determines how much air flow is available for the cooler.  Subtract the drag caused by the oil cooler itself, and now the differential pressure is even less.  It would seem that an outlet plenum with scat hose connected to louvers on the bottom of the cowl would create a lower pressure area and would enhance the airflow through  the cooler.



someone tell me where I'm fooling myself here!!!

Linn

do not archive

On 9/29/2010 2:34 PM, John Cumins wrote:   	  Quote: 	
		        

Deems

 

 	


 

If you cut back the baffling make sure to do it on the top  of the cylinders and not the bottom side.  You need to increase the differential pressure between the top of the engine and the bottom.  I have see several people trim back the front plate on the #2 cylinder but since you have the fancy cowl I am not too sure how to help you on that one.  On our Saratoga we have both oil coolers on the aft baffling right next to the #5 and # 6 cylinders and the engine stays nice and cool here in our 105 degree heat in northern California.  So I do not think it is the oil cooler air outlet causing the issues. 

  

I would be looking at getting the max air in the top of the engine and then making sure there is not blockage or reverse pressure on the bottom of the engine. 

  

If you have access to a couple of gauges it would be worth the trouble to do some pressure checks to determine the differential pressure in the cowl that will answer a lot of questions and take some guess work out of it. 

  

John Cumins 40864 

Emp done reorganizing garage for Wings 

  

    

From: [url=mailto:owner-rv10-list-server(at)matronics.com]owner-rv10-list-server(at)matronics.com (owner-rv10-list-server(at)matronics.com)[/url] [[url=mailto:owner-rv10-list-server(at)matronics.com]mailto:owner-rv10-list-server(at)matronics.com (owner-rv10-list-server(at)matronics.com)[/url]] On Behalf Of Deems Davis

Sent: Wednesday, September 29,  2010 11:12 AM

To: [url=mailto:rv10-list(at)matronics.com]rv10-list(at)matronics.com (rv10-list(at)matronics.com)[/url]

Subject: Hottest Cyl CHT



 

  

What's your hottest cylinder ?



The reason I'm asking is that mine is #6, followed closely by #2 (at) OSH I was asking around and it seemed that the same was true for several others? During the summer which lasts a while here in AZ (Today's high is 105) I need to pay attention to these during climb as # 6 will easily top 410F and with a steep/long climb will reach 420.



My initial assumption is that #6 is loosing some cooling air to the cylinders which is being sent to to the oil cooler. For those of us with the plenum, it's probably compounded due to having the oil air intake much lower and eclipsing the cylinder.



I've been noodling about how to get more cooling air through #6 & #2, and would appreciate any thoughts/efforts that others have done/attempted. I just finished installing some 'fixed cowl flaps' on the bottom of the cowl similar to what Al Gardner did,  the theory being that it would increase the lower cowl exit area and improve air flow from upper to lower cowl, but a test flight yesterday didn't indicate much if any improvement.



I've thought about cutting back the baffeling on #6 & #2 that wrapped around the lower portion of the cylinder. I recall Sam James saying that the Van's baffeling wasn't opened up enough. Thoughts????

Thanks



Deems 	  Quote: 	
		      	
http://www.matronic================= http://forums.matronics.com          - List Contribution Web generous nbsp;                        --> http://www.matronics.com/c=  	  Quote: 	
		    

	
[/url] 	


 	  Quote: 	
		  



href="http://www.matronics.com/Navigator?RV10-List">http://www.matronics.com/Navigator?RV10-List

href="[url=http://forums.matronics.com]http://forums.matronics.com">http://forums.matronics.com

href="http://www.matronics.com/contribution">http://www.matronics.com/c





=nofollow target=_blank>http://www.matronics.com/Navigator?RV10-List

et=_blank>http://forums.matronics.com

llow target=_blank>http://www.matronics.com/contribution



	


          	  Quote: 	
		  



===================================

ref="http://www.matronics.com/Navigator?RV10-List">http://www.matronics.com/Navigator?RV10-List

===================================

ums.matronics.com">http://forums.matronics.com

===================================

http://www.matronics.com/contribution">http://www.matronics.com/contribution

===================================



	


[b]

AV8ORJWC

Joined: 13 Jul 2006
Posts: 1149
Location: Aurora, Oregon "Home of VANS"

Posted: Wed Sep 29, 2010 4:38 pm Post subject: Hottest Cyl CHT

Metallurgical alteration of the longterm (life) strength of aluminum, coking of lubricating oil on the exhaust valve guides/stems and development of cracks in the proximity of exhaust valves/seats should be understood before getting too deep into temperature ranges in the 400s.  Note: Break In periods are though not exempt are less lifetime critical.

  

 Twenty plus years ago, very few operators had individual CHT sensors to warn of those impending events. These new units are great.  I concur that regardless of extra horsepower, modified coolers, higher altitudes, dysfunctional high pressure plenums, warmer climate and other factors, "Temperatures outside of the norm - Do matter".  Some friends can just afford the cost associated with such elective activities more easily than others and handles those temperature extremes better.

  

 I like Allen's 350-380 and clearly understand the importance of consistent/controlled operating temperatures.  I get increased butt dyno sensitivity at over 400.  I increase my monitoring vigilance in approaching 420 and I sure as hell understand the Danger Zone of operating above that number for periods of time during extended climb.  I have remarked to fellow pilots when I ride along that cowl flaps need opening, angle of attack needs monitoring, alternate landing sites need to be considered and then the music from Top Gun begins in my head.  A close friend with a Continental TSIO-550 got to visit the price for such wild dancing and it was an eye opener.  One of our RV-10 brethren did not head such annunciation and also got to replace some aluminum parts.  YMMV.

  

 Choose Wisely your temperatures. 

  



  John Cox



 

  From: BPA

Sent: Wed 9/29/2010 1:37 PM

To: rv10-list(at)matronics.com

Subject: RE: RV10-List: Hottest Cyl CHT

   

Gary, I’m not saying its good for them. I AM concerned at 420 if the CHT’s are run there for long periods of time, but not necessarily if only occasionally. Ideally, the best temps to run the cylinders are between 350-380. This will give you best cylinder life. I have seen cylinders that have been run in the low 430’s on aerobatic engines that have shown no noticeable effects. But then, I haven’t done any fatigue analysis on them either.  

  

Allen   

  

--

Display posts from previous:

	Matronics Email Lists Forum Index -> RV10-List	All times are GMT - 8 Hours
Page 1 of 1

Jump to:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum