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joelhaynes

Joined: 11 Jan 2006
Posts: 19
Location: Bozeman, MT

Posted: Fri Feb 15, 2008 9:13 am Post subject: WOW - What a difference

I've been flying my 7A for about 1.5 years and 150 hours.  It remains unpainted and the cowl at the time of the first flight was structurally complete but the spinner gap was never to my liking since it was nice at the top (0.25 inch) but too wide on the sides and particularly so on the bottom.  My philosophy was to get it in the air, enjoy flying, and take my time in completing the fairings and final fiberglass finishing before painting (I still like this strategy).  So over the last few weeks I spent a good 25 hours filling all the pin holes, re-working the spinner opening with some layups and flox, and getting a nice coat of primer on the cowl to hold me until the real paint goes on.  The cosmetic outcome was very nice.  Then I went flying.  Holy s**t, it's a different airplane.  I picked up 3-4 knots in cruise and my CHTs dropped 20-25 degrees.  My leaned out cruise CHTs at 2500 rpm and 7500 ft&nbs  p;were 325 deg F yesterday with the OAT around freezing.  On a 1500 fpm climb out I did not get above 350 on any cylinder.  Before the changes I would sometimes need to push the nose down when I got to around 380 on #3.  The cosmetic outcome was satisfying enough.  The added performance is gravy.

 

 Joel Haynes

 N557XW

 Bozeman, MT  More new features than ever.  Check out the new AOL Mail! 

  [quote][b]

n616tb(at)btsapps.com
Guest

Posted: Fri Feb 15, 2008 9:40 am Post subject: WOW - What a difference

Joel,  

   

To which item do you contribute the CHT temp improvement to?  To which item do you contribute the speed difference to?  

Inquiring minds.  

My CHT’s are never below 380 in cruise and well over 420 in climb out.  

Tim  

           

  

From: owner-rv-list-server(at)matronics.com [mailto:owner-rv-list-server(at)matronics.com] On Behalf Of joelrhaynes(at)aol.com

 Sent: Friday, February 15, 2008 11:11 AM

 To: rv-list(at)matronics.com

 Subject: WOW - What a difference  

  

   

I've been flying my 7A for about 1.5 years and 150 hours.  It remains unpainted and the cowl at the time of the first flight was structurally complete but the spinner gap was never to my liking since it was nice at the top (0.25 inch) but too wide on the sides and particularly so on the bottom.  My philosophy was to get it in the air, enjoy flying, and take my time in completing the fairings and final fiberglass finishing before painting (I still like this strategy).  So over the last few weeks I spent a good 25 hours filling all the pin holes, re-working the spinner opening with some layups and flox, and getting a nice coat of primer on the cowl to hold me until the real paint goes on.  The cosmetic outcome was very nice.  Then I went flying.  Holy s**t, it's a different airplane.  I picked up 3-4 knots in cruise and my CHTs dropped 20-25 degrees.  My leaned out cruise CHTs at 2500 rpm and 7500 ft&nbs p;were 325 deg F yesterday with the OAT around freezing.  On a 1500 fpm climb out I did not get above 350 on any cylinder.  Before the changes I would sometimes need to push the nose down when I got to around 380 on #3.  The cosmetic outcome was satisfying enough.  The added performance is gravy.

 

 Joel Haynes

 N557XW

 Bozeman, MT        

  

More new features than ever. Check out the new AOL Mail!  

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pitts_pilot(at)bellsouth.
Guest

Posted: Fri Feb 15, 2008 11:09 am Post subject: WOW - What a difference

I'm going to guess that the improvement was due to cutting down the air flow forward and then out of the cowl at the spinner gap.  The venturi effect there is huge!  To further seal this area, get some pipe insulating foam and fit it inside the cowl opening around the crank .... like a donut  with the cut in the foam facing outward.  Reinstall the spinner, paying no mind to the fact that the foam contacts the spinner.  A minute of engine run will trim the foam just fine and really close off this escape route for cooling air.

 Linn

 

 joelrhaynes(at)aol.com (joelrhaynes(at)aol.com) wrote:

 [quote]I've been flying my 7A for about 1.5 years and 150 hours.  It remains unpainted and the cowl at the time of the first flight was structurally complete but the spinner gap was never to my liking since it was nice at the top (0.25 inch) but too wide on the sides and particularly so on the bottom.  My philosophy was to get it in the air, enjoy flying, and take my time in completing the fairings and final fiberglass finishing before painting (I still like this strategy).  So over the last few weeks I spent a good 25 hours filling all the pin holes, re-working the spinner opening with some layups and flox, and getting a nice coat of primer on the cowl to hold me until the real paint goes on.  The cosmetic outcome was very nice.  Then I went flying.  Holy s**t, it's a different airplane.  I picked up 3-4 knots in cruise and my CHTs dropped 20-25 degrees.  My leaned out cruise CHTs at 2500 rpm and 7500 ft&nbs p;were 325 deg F yesterday with the OAT around freezing.  On a 1500 fpm climb out I did not get above 350 on any cylinder.  Before the changes I would sometimes need to push the nose down when I got to around 380 on #3.  The cosmetic outcome was satisfying enough.  The added performance is gravy.

   

 Joel Haynes

 N557XW

 Bozeman, MT      More new features than ever. Check out the new AOL Mail!

   

    	  Quote: 	
		  

	
 [b]

tracy(at)rotaryaviation.c
Guest

Posted: Fri Feb 15, 2008 12:17 pm Post subject: WOW - What a difference

I had the same experience when closing this gap.  I had no cooling improvement due to my very different cooling system (liquid cooled rotary engine) but I saw a 3 mph increase in cruise speed. 

  

 Conventional wisdom would indicate that the reduction in drag is due to the simple reduction of the gap generated turbulance.  I don't think this is correct.

  

    I think the reason for the speed increase is the reduction in the fan of air spewing out of the gap.  The air causes some kind of parasitic drag.  The spinner also acts like a centrifugal pump throwing air out of this gap.

   

  Also, cooling drag is proportional to the number of CFM flowing through the cooling inlets.   Your cooling improvement was probably due to the increase in pressure in you cooling plenum because the air was not being blead off through the spinner gap.   Even though the airflow through your cylinder fins increased, the total flow through the inlets was probably decreased - i.e., lower cooling drag.

   

 Tracy Crook 

 On Fri, Feb 15, 2008 at 12:11 PM, <joelrhaynes(at)aol.com (joelrhaynes(at)aol.com)> wrote:

 [quote]I've been flying my 7A for about 1.5 years and 150 hours.  It remains unpainted and the cowl at the time of the first flight was structurally complete but the spinner gap was never to my liking since it was nice at the top (0.25 inch) but too wide on the sides and particularly so on the bottom.  My philosophy was to get it in the air, enjoy flying, and take my time in completing the fairings and final fiberglass finishing before painting (I still like this strategy).  So over the last few weeks I spent a good 25 hours filling all the pin holes, re-working the spinner opening with some layups and flox, and getting a nice coat of primer on the cowl to hold me until the real paint goes on.  The cosmetic outcome was very nice.  Then I went flying.  Holy s**t, it's a different airplane.  I picked up 3-4 knots in cruise and my CHTs dropped 20-25 degrees.  My leaned out cruise CHTs at 2500 rpm and 7500 ft&nbs p;were 325 deg F yesterday with the OAT around freezing.  On a 1500 fpm climb out I did not get above 350 on any cylinder.  Before the changes I would sometimes need to push the nose down when I got to around 380 on #3.  The cosmetic outcome was satisfying enough.  The added performance is gravy.

 

Joel Haynes

N557XW

Bozeman, MT    More new features than ever. Check out the new AOL Mail!



 	  Quote: 	
		  



t="_blank">http://www.matronics.com/Navigator?RV-List

ttp://forums.matronics.com

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



	
[b]

n616tb(at)btsapps.com
Guest

Posted: Fri Feb 15, 2008 12:43 pm Post subject: WOW - What a difference

I am having a hard time visualizing where this pipe foam is being put.  Isn’t the flywheel back there also turning?  Do you have any pictures of this installed?  

Thanks  

Tim  

           

  

From: owner-rv-list-server(at)matronics.com [mailto:owner-rv-list-server(at)matronics.com] On Behalf Of linn Walters

 Sent: Friday, February 15, 2008 1:06 PM

 To: rv-list(at)matronics.com

 Subject: Re: WOW - What a difference  

  

   

I'm going to guess that the improvement was due to cutting down the air flow forward and then out of the cowl at the spinner gap.  The venturi effect there is huge!  To further seal this area, get some pipe insulating foam and fit it inside the cowl opening around the crank ..... like a donut  with the cut in the foam facing outward.  Reinstall the spinner, paying no mind to the fact that the foam contacts the spinner.  A minute of engine run will trim the foam just fine and really close off this escape route for cooling air.

 Linn

 

 joelrhaynes(at)aol.com (joelrhaynes(at)aol.com) wrote:

 

   

I've been flying my 7A for about 1.5 years and 150 hours.  It remains unpainted and the cowl at the time of the first flight was structurally complete but the spinner gap was never to my liking since it was nice at the top (0.25 inch) but too wide on the sides and particularly so on the bottom.  My philosophy was to get it in the air, enjoy flying, and take my time in completing the fairings and final fiberglass finishing before painting (I still like this strategy).  So over the last few weeks I spent a good 25 hours filling all the pin holes, re-working the spinner opening with some layups and flox, and getting a nice coat of primer on the cowl to hold me until the real paint goes on.  The cosmetic outcome was very nice.  Then I went flying.  Holy s**t, it's a different airplane.  I picked up 3-4 knots in cruise and my CHTs dropped 20-25 degrees.  My leaned out cruise CHTs at 2500 rpm and 7500 ft&nbs p;were 325 deg F yesterday with the OAT around freezing.  On a 1500 fpm climb out I did not get above 350 on any cylinder.  Before the changes I would sometimes need to push the nose down when I got to around 380 on #3.  The cosmetic outcome was satisfying enough.  The added performance is gravy.

 

 Joel Haynes

 N557XW

 Bozeman, MT         

  

More new features than ever. Check out the new AOL Mail!  

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pitts_pilot(at)bellsouth.
Guest

Posted: Fri Feb 15, 2008 1:26 pm Post subject: WOW - What a difference

Tim Bryan wrote:

 Tim, let me answer last question first   

 

 Do you have any pictures of this installed?

 No.

 

 Isn’t the flywheel back there also turning?

 Yes!  At least I hope it is!!!   

 I think I see your point.  If the flywheel doesn't leave enough room between cowl and flywheel for the foam, you can split the foam in half and just glue the front piece on.  Or you may just let the flywheel custom fit itself in the foam like the spinner does. This may be preferable if the 'hole in the donut' is small.

 

 And finally:

 I am having a hard time visualizing where this pipe foam is being put. 

 

 Bear in mind that I've not seen my -10 cowl yet!!!  I've done this on other airplanes.

 The cowl should have a round, flat, face that fits between the flywheel teeth and the spinner.  When the cowl is in place, there's a hole where the crank pokes through ..... between the inlets ...... and this is the 'hole in the donut'.  Now, this is where things may get confusing ... in my mind too.  I've never done this to a constant speed prop, so there may be some difference here, but not much.  On the fixed pitch spinner, the back plate lip bends aft.  I'm thinking that on some constant speeds, the lip points forward.  Someone can help me out here!!!

 

 Anyway, the foam has a slit down it lengthwise.  Fit it around the 'hole in the donut' like a huge rubber grommet.  Place the spinner back plate on the prop flange to check for fit.  On the cowls I've done this to, the new 'grommet' fit snugly underneath the lip of the backing plate ..... except where the nutplates were.  The first two or three revolutions relieved that interference!  Glue it down with yellow 3m weatherstrip glue .... monkey snot as somebody previously said!!!  

 

 All you need to remember is to slit the foam where the upper and lower cowl joins!!!

 

 Hope this helps!!!

  [quote]         v\:* {behavior:url(#default#VML);} o\:* {behavior:url(#default#VML);} w\:* {behavior:url(#default#VML);} .shape {behavior:url(#default#VML);}  <![endif]-->      st1\:*{behavior:url(#default#ieooui) }  <![endif]-->          <![endif]-->       <![endif]-->         

I am having a hard time visualizing where this pipe foam is being put.  Isn’t the flywheel back there also turning?  Do you have any pictures of this installed?   

Thanks   

Tim   

             

   

From: owner-rv-list-server(at)matronics.com (owner-rv-list-server(at)matronics.com) [mailto:owner-rv-list-server(at)matronics.com (owner-rv-list-server(at)matronics.com)] On Behalf Of linn Walters

   Sent: Friday, February 15, 2008 1:06 PM

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

   Subject: Re: RV-List: WOW - What a difference   

   

    

I'm going to guess that the improvement was due to cutting down the air flow forward and then out of the cowl at the spinner gap.  The venturi effect there is huge!  To further seal this area, get some pipe insulating foam and fit it inside the cowl opening around the crank ..... like a donut  with the cut in the foam facing outward.  Reinstall the spinner, paying no mind to the fact that the foam contacts the spinner.  A minute of engine run will trim the foam just fine and really close off this escape route for cooling air.

 Linn

   

   joelrhaynes(at)aol.com (joelrhaynes(at)aol.com) wrote:

   

      

I've been flying my 7A for about 1.5 years and 150 hours.  It remains unpainted and the cowl at the time of the first flight was structurally complete but the spinner gap was never to my liking since it was nice at the top (0.25 inch) but too wide on the sides and particularly so on the bottom.  My philosophy was to get it in the air, enjoy flying, and take my time in completing the fairings and final fiberglass finishing before painting (I still like this strategy).  So over the last few weeks I spent a good 25 hours filling all the pin holes, re-working the spinner opening with some layups and flox, and getting a nice coat of primer on the cowl to hold me until the real paint goes on.  The cosmetic outcome was very nice.  Then I went flying.  Holy s**t, it's a different airplane.  I picked up 3-4 knots in cruise and my CHTs dropped 20-25 degrees.  My leaned out cruise CHTs at 2500 rpm and 7500 ft&nbs p;were 325 deg F yesterday with the OAT around freezing.  On a 1500 fpm climb out I did not get above 350 on any cylinder.  Before the changes I would sometimes need to push the nose down when I got to around 380 on #3.  The cosmetic outcome was satisfying enough.  The added performance is gravy.

   

 Joel Haynes

 N557XW

   Bozeman, MT            

   

More new features than ever. Check out the new AOL Mail!   

    	  Quote: 	
		     	
   

     	  Quote: 	
		    http://www.matronics.com/Navigator?RV-Listhttp://forums.matronics.com 	
0    	  Quote: 	
		   	
1    	  Quote: 	
		   	
2   

   

    	  Quote: 	
		   	
3 [b]

tedd(at)vansairforce.org
Guest

Posted: Sat Feb 16, 2008 10:36 am Post subject: WOW - What a difference

This brings up a question I've often wondered about.  Would it be simpler and

more effective to use a plenum, rather than relying on the fit of the cowl and

baffles, to ensure good cooling and minimum cooling drag?  I'm thinking that,

while the plenum itself is more work up front, it might eliminate a lot of time

spend fiddling around with the cowl and baffles later.



Tedd McHenry

Surrey, BC, Canada

robin1(at)mrmoisture.com
Guest

Posted: Sat Feb 16, 2008 4:38 pm Post subject: WOW - What a difference

 	  Quote: 	
		  > would it be simpler and more effective to use a plenum, rather than

relying on the fit of the cowl and
	


baffles, to ensure good cooling and minimum cooling drag? <<



My thinking exactly. All my future RV's will have either metal or

composite/glass plenums. 



Robin

Do Not Archive

bobbyhester(at)newwavecom
Guest

Posted: Sat Feb 16, 2008 5:32 pm Post subject: WOW - What a difference

At what outside air temp are you talking about here? I can see this at 90-100 degrees OAT, but at 20-50 OAT you should not see this. I am currently flying without my leg fairing and pants and on 90+ OAT days I see 420 on climb out, but I do not let it get over that, I level off and pull the throttle back until it comes back to 400. I also see between 380-390 in cruise. 40 degree days I see about 385 climb out and 350 cruise. I'm hoping the have the leg fairing on in about a month.

  	  Quote: 	
		  ----

Surfing the web from Hopkinsville, KY

Visit my flying RV7A web page:

http://home.newwavecomm.net/bobbyhester/MyFlyingRV7A.htm



	
 

 

 Tim Bryan wrote: [quote]         v\:* {behavior:url(#default#VML);} o\:* {behavior:url(#default#VML);} w\:* {behavior:url(#default#VML);} .shape {behavior:url(#default#VML);}  <![endif]-->      st1\:*{behavior:url(#default#ieooui) }  <![endif]-->             

Joel,   

    

To which item do you contribute the CHT temp improvement to?  To which item do you contribute the speed difference to?   

Inquiring minds.   

My CHT’s are never below 380 in cruise and well over 420 in climb out.   

Tim   

             

   

From: owner-rv-list-server(at)matronics.com (owner-rv-list-server(at)matronics.com) [mailto:owner-rv-list-server(at)matronics.com (owner-rv-list-server(at)matronics.com)] On Behalf Of joelrhaynes(at)aol.com (joelrhaynes(at)aol.com)

   Sent: Friday, February 15, 2008 11:11 AM

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

   Subject: WOW - What a difference   

   

    

I've been flying my 7A for about 1.5 years and 150 hours.  It remains unpainted and the cowl at the time of the first flight was structurally complete but the spinner gap was never to my liking since it was nice at the top (0.25 inch) but too wide on the sides and particularly so on the bottom.  My philosophy was to get it in the air, enjoy flying, and take my time in completing the fairings and final fiberglass finishing before painting (I still like this strategy).  So over the last few weeks I spent a good 25 hours filling all the pin holes, re-working the spinner opening with some layups and flox, and getting a nice coat of primer on the cowl to hold me until the real paint goes on.  The cosmetic outcome was very nice.  Then I went flying.  Holy s**t, it's a different airplane.  I picked up 3-4 knots in cruise and my CHTs dropped 20-25 degrees.  My leaned out cruise CHTs at 2500 rpm and 7500 ft&nbs p;were 325 deg F yesterday with the OAT around freezing.  On a 1500 fpm climb out I did not get above 350 on any cylinder.  Before the changes I would sometimes need to push the nose down when I got to around 380 on #3.  The cosmetic outcome was satisfying enough.  The added performance is gravy.

   

 Joel Haynes

 N557XW

   Bozeman, MT         

   

More new features than ever. Check out the new AOL Mail!   

    	  Quote: 	
		     	
0    	  Quote: 	
		   	
1   

   

    	  Quote: 	
		   	
2 [b]

bobbyhester(at)newwavecom
Guest

Posted: Sat Feb 16, 2008 5:32 pm Post subject: WOW - What a difference

At what outside air temp are you talking about here? I can see this at 90-100 degrees OAT, but at 20-50 OAT you should not see this. I am currently flying without my leg fairing and pants and on 90+ OAT days I see 420 on climb out, but I do not let it get over that, I level off and pull the throttle back until it comes back to 400. I also see between 380-390 in cruise. 40 degree days I see about 385 climb out and 350 cruise. I'm hoping the have the leg fairing on in about a month.

 

 XP-0360 one mag one Lightspeed Ign.

  	  Quote: 	
		  ----

Surfing the web from Hopkinsville, KY

Visit my flying RV7A web page:

http://home.newwavecomm.net/bobbyhester/MyFlyingRV7A.htm



	
 

 

 Tim Bryan wrote: [quote]         v\:* {behavior:url(#default#VML);} o\:* {behavior:url(#default#VML);} w\:* {behavior:url(#default#VML);} .shape {behavior:url(#default#VML);}  <![endif]-->      st1\:*{behavior:url(#default#ieooui) }  <![endif]-->             

Joel,   

    

To which item do you contribute the CHT temp improvement to?  To which item do you contribute the speed difference to?   

Inquiring minds.   

My CHT’s are never below 380 in cruise and well over 420 in climb out.   

Tim   

             

   

From: owner-rv-list-server(at)matronics.com (owner-rv-list-server(at)matronics.com) [mailto:owner-rv-list-server(at)matronics.com (owner-rv-list-server(at)matronics.com)] On Behalf Of joelrhaynes(at)aol.com (joelrhaynes(at)aol.com)

   Sent: Friday, February 15, 2008 11:11 AM

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

   Subject: WOW - What a difference   

   

    

I've been flying my 7A for about 1.5 years and 150 hours.  It remains unpainted and the cowl at the time of the first flight was structurally complete but the spinner gap was never to my liking since it was nice at the top (0.25 inch) but too wide on the sides and particularly so on the bottom.  My philosophy was to get it in the air, enjoy flying, and take my time in completing the fairings and final fiberglass finishing before painting (I still like this strategy).  So over the last few weeks I spent a good 25 hours filling all the pin holes, re-working the spinner opening with some layups and flox, and getting a nice coat of primer on the cowl to hold me until the real paint goes on.  The cosmetic outcome was very nice.  Then I went flying.  Holy s**t, it's a different airplane.  I picked up 3-4 knots in cruise and my CHTs dropped 20-25 degrees.  My leaned out cruise CHTs at 2500 rpm and 7500 ft&nbs p;were 325 deg F yesterday with the OAT around freezing.  On a 1500 fpm climb out I did not get above 350 on any cylinder.  Before the changes I would sometimes need to push the nose down when I got to around 380 on #3.  The cosmetic outcome was satisfying enough.  The added performance is gravy.

   

 Joel Haynes

 N557XW

   Bozeman, MT         

   

More new features than ever. Check out the new AOL Mail!   

    	  Quote: 	
		     	
0    	  Quote: 	
		   	
1   

   

    	  Quote: 	
		   	
2 [b]

pitts_pilot(at)bellsouth.
Guest

Posted: Sat Feb 16, 2008 6:31 pm Post subject: WOW - What a difference

Tedd McHenry wrote:



 	  Quote: 	
		  



This brings up a question I've often wondered about.  Would it be simpler and

more effective to use a plenum, rather than relying on the fit of the cowl and

baffles, to ensure good cooling and minimum cooling drag?  I'm thinking that,

while the plenum itself is more work up front, it might eliminate a lot of time

spend fiddling around with the cowl and baffles later.



Tedd McHenry

Surrey, BC, Canada



BINGO!!! 
	


At least in my mind.  MY bird will sport a plenum when it gets to that 

point.  My only gripe with the plenum is that it's harder to get to the 

plugs to clean them ...... but proper leaning should take care of that.  

I have seen some with hinged plenums, but that seems like more weight 

and build time.  I'll just use screws to anchor the plenum top ...... a 

battery powered  screwdriver will make that task a quick one.

Linn

do not archive



 	  Quote:

n616tb(at)btsapps.com
Guest

Posted: Sun Feb 17, 2008 10:49 am Post subject: WOW - What a difference

Hi Bobby,  

   

I have posted about this many times.  My oil temps have always been way too low around 165 with a door mostly closed behind the oil cooler mounted on the back of the baffles like the drawings.  My CHT’s have always been very high.  This last summer I was pushing 478 after climb out and I reduce throttle and RPM as soon as I reach about 500 feet AGL.  In cruise I was getting more like 430 to 450.  I installed baffles and managed to get the climb out down to 458 and the cruise to 420.  Obviously I see lower numbers in cooler temps like I posted below, but it still isn’t very good.  I have yet to find anything that would make mine so much different than other RV’s.  

   

Tim  

           

  

From: owner-rv-list-server(at)matronics.com [mailto:owner-rv-list-server(at)matronics.com] On Behalf Of Bobby Hester

 Sent: Saturday, February 16, 2008 7:28 PM

 To: rv-list(at)matronics.com

 Subject: Re: WOW - What a difference  

  

   

At what outside air temp are you talking about here? I can see this at 90-100 degrees OAT, but at 20-50 OAT you should not see this. I am currently flying without my leg fairing and pants and on 90+ OAT days I see 420 on climb out, but I do not let it get over that, I level off and pull the throttle back until it comes back to 400. I also see between 380-390 in cruise. 40 degree days I see about 385 climb out and 350 cruise. I'm hoping the have the leg fairing on in about a month.

 

 XP-0360 one mag one Lightspeed Ign.

 

    	  Quote: 	
		  ----Surfing the web from Hopkinsville, KYVisit my flying RV7A web page:http://home.newwavecomm.net/bobbyhester/MyFlyingRV7A.htm 	
  



 

 Tim Bryan wrote:   

Joel,  

   

To which item do you contribute the CHT temp improvement to?  To which item do you contribute the speed difference to?  

Inquiring minds.  

My CHT’s are never below 380 in cruise and well over 420 in climb out.  

Tim  

           

  

From: owner-rv-list-server(at)matronics.com (owner-rv-list-server(at)matronics.com) [mailto:owner-rv-list-server(at)matronics.com (owner-rv-list-server(at)matronics.com)] On Behalf Of joelrhaynes(at)aol.com (joelrhaynes(at)aol.com)

 Sent: Friday, February 15, 2008 11:11 AM

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

 Subject: WOW - What a difference  

  

   

I've been flying my 7A for about 1.5 years and 150 hours.  It remains unpainted and the cowl at the time of the first flight was structurally complete but the spinner gap was never to my liking since it was nice at the top (0.25 inch) but too wide on the sides and particularly so on the bottom.  My philosophy was to get it in the air, enjoy flying, and take my time in completing the fairings and final fiberglass finishing before painting (I still like this strategy).  So over the last few weeks I spent a good 25 hours filling all the pin holes, re-working the spinner opening with some layups and flox, and getting a nice coat of primer on the cowl to hold me until the real paint goes on.  The cosmetic outcome was very nice.  Then I went flying.  Holy s**t, it's a different airplane.  I picked up 3-4 knots in cruise and my CHTs dropped 20-25 degrees.  My leaned out cruise CHTs at 2500 rpm and 7500 ft&nbs p;were 325 deg F yesterday with the OAT around freezing.  On a 1500 fpm climb out I did not get above 350 on any cylinder.  Before the changes I would sometimes need to push the nose down when I got to around 380 on #3.  The cosmetic outcome was satisfying enough.  The added performance is gravy.

 

 Joel Haynes

 N557XW

 Bozeman, MT          

  

  

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        [quote][b]

dale1rv6(at)comcast.net
Guest

Posted: Sun Feb 17, 2008 12:21 pm Post subject: WOW - What a difference

Hi Tim,  

What have you done to prove the accuracy of your temp gauges? I would do some serious laboratory type testing of my entire CHT gauge system if I had your results. Take an oven thermometer and your CHT probe, rig up cooking oil in a small deep pan. Set up a steady support to hold the pan next to the engine where the probe will reach. The heat source does not need to be close to the engine, just move the pan over when it is up to 350 F. Drop the probe in and check your instrument panel, give it time to stabilize. While you are waiting you can recheck the oven thermometer to monitor its reading. Cooking oil can test up to 400 F for sure. I would also test the oven thermometer in boiling water for 212 F before I went to the plane.  

I am looking forward to the day you tell us this problem is solved! Good luck!  

Dale  

RV6a 990 hrs  

         

  

From: owner-rv-list-server(at)matronics.com [mailto:owner-rv-list-server(at)matronics.com] On Behalf Of Tim Bryan

 Sent: Sunday, February 17, 2008 1:41 PM

 To: rv-list(at)matronics.com

 Subject: RE: WOW - What a difference  

  

   

Hi Bobby,  

   

I have posted about this many times.  My oil temps have always been way too low around 165 with a door mostly closed behind the oil cooler mounted on the back of the baffles like the drawings.  My CHT’s have always been very high.  This last summer I was pushing 478 after climb out and I reduce throttle and RPM as soon as I reach about 500 feet AGL.  In cruise I was getting more like 430 to 450.  I installed baffles and managed to get the climb out down to 458 and the cruise to 420.  Obviously I see lower numbers in cooler temps like I posted below, but it still isn’t very good.  I have yet to find anything that would make mine so much different than other RV’s.  

   

Tim  

   [quote]  [b]

klwerner(at)comcast.net
Guest

Posted: Sun Feb 17, 2008 12:52 pm Post subject: WOW - What a difference

Hi Dale,

 Keep in mind that the boiling temp of  water is altitude dependent... Higher field altitude, lower boiling point. Here  in Albuquerque (at) 5000ft, we would never see 212F before water starts  boiling away! 

 FWIW,

 Konrad

 [quote]   ---

n801bh(at)netzero.com
Guest

Posted: Sun Feb 17, 2008 6:37 pm Post subject: WOW - What a difference

Konrad is correct, Here in Jackson Hole Wy, (at) 6500' msl water boils at about 186 f.

Ben Haas

N801BH

www.haaspowerair.com



-- "Konrad L. Werner" <klwerner(at)comcast.net> wrote:

<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /> Hi Dale,

 Keep in mind that the boiling temp of water is altitude dependent... Higher field altitude, lower boiling point. Here in Albuquerque (at) 5000ft, we would never see 212F before water starts boiling away! 

 FWIW,

 Konrad

 [quote] ---

n616tb(at)btsapps.com
Guest

Posted: Sun Feb 17, 2008 9:00 pm Post subject: WOW - What a difference

Just for a data point, my CHT is in the VM1000 and I don’t have great faith in this system.  I will perform this test tomorrow and report back.  

Tim  

           

  

From: owner-rv-list-server(at)matronics.com [mailto:owner-rv-list-server(at)matronics.com] On Behalf Of Dale Walter

 Sent: Sunday, February 17, 2008 2:19 PM

 To: rv-list(at)matronics.com

 Subject: RE: WOW - What a difference  

  

   

Hi Tim,  

What have you done to prove the accuracy of your temp gauges? I would do some serious laboratory type testing of my entire CHT gauge system if I had your results. Take an oven thermometer and your CHT probe, rig up cooking oil in a small deep pan. Set up a steady support to hold the pan next to the engine where the probe will reach. The heat source does not need to be close to the engine, just move the pan over when it is up to 350 F. Drop the probe in and check your instrument panel, give it time to stabilize. While you are waiting you can recheck the oven thermometer to monitor its reading. Cooking oil can test up to 400 F for sure. I would also test the oven thermometer in boiling water for 212 F before I went to the plane.  

I am looking forward to the day you tell us this problem is solved! Good luck!  

Dale  

RV6a 990 hrs  

         

  

From: owner-rv-list-server(at)matronics.com [mailto:owner-rv-list-server(at)matronics.com] On Behalf Of Tim Bryan

 Sent: Sunday, February 17, 2008 1:41 PM

 To: rv-list(at)matronics.com

 Subject: RE: WOW - What a difference  

  

   

Hi Bobby,  

   

I have posted about this many times.  My oil temps have always been way too low around 165 with a door mostly closed behind the oil cooler mounted on the back of the baffles like the drawings.  My CHT’s have always been very high.  This last summer I was pushing 478 after climb out and I reduce throttle and RPM as soon as I reach about 500 feet AGL.  In cruise I was getting more like 430 to 450.  I installed baffles and managed to get the climb out down to 458 and the cruise to 420.  Obviously I see lower numbers in cooler temps like I posted below, but it still isn’t very good.  I have yet to find anything that would make mine so much different than other RV’s.  

   

Tim  

   [quote] [b]

chasb(at)satx.rr.com
Guest

Posted: Mon Feb 18, 2008 9:21 am Post subject: WOW - What a difference

I also have had high CHT temps. Even with cooler outside air, my #3  

CHT will exceed 450 in a long fast cruise climb. Unlike you, I have  

high oil temps which I associate with the high CHT. I haven't checked  

the CHT probes for temp accuracy, but I did check the oil temp probe  

and it was right on. My oil temp usually settles around 195 in  

cruise, but will approach the red line in a long climb - again with  

cool outside temps. It does cool down in cruise as do the CHTs. After  

about 15 - 20 minutes at cruise, all my CHTs are within about 25  

degrees of each other with a low of 375 and a high of 400 - all a bit  

on the high side.



I only have about 20 hours on a rebuilt, zero time IO-320, so I am  

hoping a few more hours of break in will solve all the temp problems.  

I am planning on increasing the SCAT tube to my oil cooler plenum  

from a 3 inch to a 4 inch.



I found this thread interesting as my baffle is very tight but I do  

have about a 3/8th to 5/16 gap between my cowl and the spinner.  

Something to work on in the future.



Charlie Brame

RV-6A  N11CB

San Antonio



-------------------------------------------



 	  Quote: 	
		   Time: 10:49:42 AM PST US

 From: "Tim Bryan" <n616tb(at)btsapps.com>

 Subject: RE: WOW - What a difference



 Hi Bobby,

 I have posted about this many times.  My oil temps have always been  

 way too

 low around 165 with a door mostly closed behind the oil cooler  

 mounted on

 the back of the baffles like the drawings.  My CHT's have always  

 been very

 high.  This last summer I was pushing 478 after climb out and I reduce

 throttle and RPM as soon as I reach about 500 feet AGL.  In cruise  

 I was

 getting more like 430 to 450.  I installed baffles and managed to  

 get the

 climb out down to 458 and the cruise to 420.  Obviously I see lower  

 numbers

 in cooler temps like I posted below, but it still isn't very good.   

 I have

 yet to find anything that would make mine so much different than  

 other RV's.

 Tim

panamared5(at)brier.net
Guest

Posted: Mon Feb 18, 2008 10:11 am Post subject: WOW - What a difference

 	  Quote: 	
		  I also have had high CHT temps. Even with cooler outside air, my #3

CHT will exceed 450 in a long fast cruise climb. Unlike you, I have

high oil temps which I associate with the high CHT. I haven't checked

the CHT probes for temp accuracy, but I did check the oil temp probe

and it was right on. My oil temp usually settles around 195 in

cruise, but will approach the red line in a long climb - again with

cool outside temps. It does cool down in cruise as do the CHTs. After

about 15 - 20 minutes at cruise, all my CHTs are within about 25

degrees of each other with a low of 375 and a high of 400 - all a bit

on the high side

D


	


I don't know how to say this very well, but here goes.  Tight baffles 

may cause cooling problems.



I had this problem when trying to balance the CHTs, as # 3 and #4 

cylinders were hotter that #1 and #2.  The solution from someone on 

the list was to put a washer spacer between the back cylinders and 

the baffle.  This would allow more cooling air to pass around those 

cylinders.   This made a big difference for me.



BTW, I have trouble getting oil temps to reach 180 degrees, and I can 

usually get it there after a long  climb, usually to 8-10K feet.  I 

have a stock cowl and stock baffles.



Bob

RV6 "Wicked Witch of the West"

kboatright1(at)comcast.ne
Guest

Posted: Mon Feb 18, 2008 3:57 pm Post subject: WOW - What a difference

---

klwerner(at)comcast.net
Guest

Posted: Mon Feb 18, 2008 4:13 pm Post subject: WOW - What a difference

Hi Kyle,

 I don't understand how a 1" air  blocker in front of the # 1 would increase your cooling on the rearward #  3. I can see how the  blocker would make both cylinders become more even in temps, but more  by running # 1 a bit hotter instead of # 3 cooler... Could you explain  this to me please.

 Thanks,

 Konrad

 [quote]   ---

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