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rbibb

Joined: 16 Jul 2009
Posts: 37

Posted: Mon Sep 28, 2009 3:24 am Post subject: Ram Air Oil Cooler Inlet - input requested

In following the thread on the James Plenum and various others with cooling problems I have been thinking about potential alternatives for my RV-10 setup (it’s down the road as I’m just starting main fuselage).  

   

For the aerodynamicists out there:  How would a larger intake scoop that had in internal split to feed intake air as well as oil cooler input work IYHO?  I’m thinking making the inlet a large affair that has a flow divider to send air into the FI body and a separate path (via flex hose) to the Oil Cooler,  This allows the plenum to concentrate on supplying cooling air to the cylinders without having any flow diverted to the oil cooler.  Similar to Robin Marks approach shown below but with the input combined into one input “hole” in the cowling.  

   

As an electrical engineer I should know better than to delve into the world of fluid dynamics but I figure that is what the “experimental” designation is all about.  

     

Richard Bibb  

972-771-2598  

972-835-5979 mobile  

   

        

  

  

   

Note: Ram Oil Cooler inlet just below Pilots Side Inlet   



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Kelly McMullen

Joined: 16 Apr 2008
Posts: 1188
Location: Sun Lakes AZ

Posted: Mon Sep 28, 2009 4:42 am Post subject: Ram Air Oil Cooler Inlet - input requested

Caution, my current aircraft has an oil cooler mounted on the lower cowling, not much lower than where Robin's inlet is located. Unfortunately, the manufacturer did no testing of that location, and in a climb it is enough of a low pressure area that flow can actually reverse, passing from cylinder bottoms out the oil cooler. Not good, and most every example I know of runs 210-215 oil temps. The only solution is for my aircraft is to relocate the oil cooler to the rear top of the engine baffling. I suppose what really needs examining is whether the engine air outlet is large enough or could benefit from cowl flaps. It is unfortunate that the prototypes didn't get any testing in AZ or TX to optimize engine cooling.

 

On Mon, Sep 28, 2009 at 7:23 AM, Richard Bibb <rbibb(at)tomet.net (rbibb(at)tomet.net)> wrote:

[quote]               

In following the thread on the James Plenum and various others with cooling problems I have been thinking about potential alternatives for my RV-10 setup (it’s down the road as I’m just starting main fuselage).  

   

For the aerodynamicists out there:  How would a larger intake scoop that had in internal split to feed intake air as well as oil cooler input work IYHO?  I’m thinking making the inlet a large affair that has a flow divider to send air into the FI body and a separate path (via flex hose) to the Oil Cooler,  This allows the plenum to concentrate on supplying cooling air to the cylinders without having any flow diverted to the oil cooler.  Similar to Robin Marks approach shown below but

[b]

_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor
KCHD

jdriggs49(at)msn.com
Guest

Posted: Mon Sep 28, 2009 5:50 am Post subject: Ram Air Oil Cooler Inlet - input requested

I have been considering the same problem on the -10 I'm building. So C every airshow I go to I look to see what other manufacturers have done. My favorite is the Navion that used a NACA duct plumbed down to the oil cooler. It came off the right side of the cowling.  Simple and elegant.   Date: Mon C 28 Sep 2009 08:41:52 -0400

Subject: Re: Ram Air Oil Cooler Inlet - input requested

From: apilot2(at)gmail.com

To: rv10-list(at)matronics.com

Caution C my current aircraft has an oil cooler mounted on the lower cowling C not much lower than where Robin's inlet is located. Unfortunately C the manufacturer did no testing of that location C and in a climb it is enough of a low pressure area that flow can actually reverse C passing from cylinder bottoms out the oil cooler. Not good C and most every example I know of runs 210-215 oil temps. The only solution is for my aircraft is to relocate the oil cooler to the rear top of the engine baffling. I suppose what really needs examining is whether the engine air outlet is large enough or could benefit from cowl flaps. It is unfortunate that the prototypes didn't get any testing in AZ or TX to optimize engine cooling.

 On Mon C Sep 28 C 2009 at 7:23 AM C Richard Bibb <rbibb(at)tomet.net (rbibb(at)tomet.net)> wrote:

  	  Quote: 	
		     In following the thread on the James Plenum and various others with cooling problems I have been thinking about potential alternatives for my RV-10 setup (it’s down the road as I’m just starting main fuselage).

 For the aerodynamicists out there:  How would a larger intake scoop that had in internal split to feed intake air as well as oil cooler input work IYHO?  I’m thinking making the inlet a large affair that has a flow divider to send air into the FI body and a separate path (via flex hose) to the Oil Cooler C  This allows the plenum to concentrate on supplying cooling air to the cylinders without having any flow diverted to the oil cooler.  Similar to Robin Marks approach shown below but

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

ronics.com

ww.matronics.com/contribution

 		 	   		  Insert movie times and more without leaving Hotmail®. See how.  [quote][b]

rbibb

Joined: 16 Jul 2009
Posts: 37

Posted: Mon Sep 28, 2009 6:02 am Post subject: Ram Air Oil Cooler Inlet - input requested

Well I wasn’t thinking of mounting the oil cooler on the cowl just deriving the source of air for the cooler (mounting in stock location but perhaps modified mount to reflect change in air source geometry) from a combined induction/oil cooler inlet.  The idea is to eliminate the source of air for the oil cooer from the rear of the baffles (whether inside a plenum or not) as to increase cooling air for the cylinders.  That creates the problem of creating an air source for the cooler.  Rather than create a separate inlet I was thinking of creating a larger “mouth”  on the below-cowl scoop for the induction and creating some sort of flow divider to send some air to the inlet and some to the cooler.    

   

Not being educated in fluid dynamics I’m looking for general guidelines as to an efficient method of engineering such an inlet/splitter combo.  

   

Thanks for the warning…..  

     

Richard Bibb  

972-771-2598  

972-835-5979 mobile  

   

        

  

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

 Sent: Monday, September 28, 2009 7:42 AM

 To: rv10-list(at)matronics.com

 Subject: Re: Ram Air Oil Cooler Inlet - input requested  

  

   

Caution, my current aircraft has an oil cooler mounted on the lower cowling, not much lower than where Robin's inlet is located. Unfortunately, the manufacturer did no testing of that location, and in a climb it is enough of a low pressure area that flow can actually reverse, passing from cylinder bottoms out the oil cooler. Not good, and most every example I know of runs 210-215 oil temps. The only solution is for my aircraft is to relocate the oil cooler to the rear top of the engine baffling. I suppose what really needs examining is whether the engine air outlet is large enough or could benefit from cowl flaps. It is unfortunate that the prototypes didn't get any testing in AZ or TX to optimize engine cooling.    

On Mon, Sep 28, 2009 at 7:23 AM, Richard Bibb <rbibb(at)tomet.net (rbibb(at)tomet.net)> wrote:      

In following the thread on the James Plenum and various others with cooling problems I have been thinking about potential alternatives for my RV-10 setup (it’s down the road as I’m just starting main fuselage).  

   

For the aerodynamicists out there:  How would a larger intake scoop that had in internal split to feed intake air as well as oil cooler input work IYHO?  I’m thinking making the inlet a large affair that has a flow divider to send air into the FI body and a separate path (via flex hose) to the Oil Cooler,  This allows the plenum to concentrate on supplying cooling air to the cylinders without having any flow diverted to the oil cooler.  Similar to Robin Marks approach shown below but  

  

  

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pitts_pilot(at)bellsouth.
Guest

Posted: Mon Sep 28, 2009 6:52 am Post subject: Ram Air Oil Cooler Inlet - input requested

Like you, my background is in electronics, so my comments may not help! 

  I don't think the problem is in robbing the available air from the 

cylinders, it's finding a balance in the area of entrance air Vs exit 

air, and finding a less-obstructed path for the air.  Lopresti was an 

expert at it, and his son is carrying on the effort.  Look at the size 

of the holes in some 'certificated' cowls Vs the Swift Fury or the 

Lancair.  I'll go the plenum route ..... cowl seals leak ..... and I'll 

use a manometer to try and balance the pressures.  Providing for good 

exit flows seem to help a lot.

Linn

Richard Bibb wrote:

 	  Quote: 	
		   Well I wasn’t thinking of mounting the oil cooler on the cowl just 

 deriving the source of air for the cooler (mounting in stock location 

 but perhaps modified mount to reflect change in air source geometry) 

 from a combined induction/oil cooler inlet.  The idea is to eliminate 

 the source of air for the oil cooer from the rear of the baffles 

 (whether inside a plenum or not) as to increase cooling air for the 

 cylinders.  That creates the problem of creating an air source for the 

 cooler.  Rather than create a separate inlet I was thinking of creating 

 a larger “mouth”  on the below-cowl scoop for the induction and creating 

 some sort of flow divider to send some air to the inlet and some to the 

 cooler. 

 

  

 

 Not being educated in fluid dynamics I’m looking for general guidelines 

 as to an efficient method of engineering such an inlet/splitter combo.

 

  

 

 Thanks for the warning…..

 

  

 

 Richard Bibb

 

 972-771-2598

 

 972-835-5979 mobile

rbibb

Joined: 16 Jul 2009
Posts: 37

Posted: Mon Sep 28, 2009 7:27 am Post subject: Ram Air Oil Cooler Inlet - input requested

My thought was it would be easier to balance the flow if you didn't have a

big 3" round exit on one side of the engine.   But I'm waiting for the

aerodynamicists to weigh in here...



Richard Bibb

972-771-2598

972-835-5979 mobile

 

 



--

jdriggs49(at)msn.com
Guest

Posted: Mon Sep 28, 2009 8:03 am Post subject: Ram Air Oil Cooler Inlet - input requested

The Navion had the oil cooler mounted on the firewall but the NACA duct was on the cowl side with SCAT tube running back about 24" to the oil cooler and ducting downward. There has been demonstrated to be very little air entering the front of the cowl behind the prop in a lot of the angles of flight. The sides alway pretty much has air passing over them.

  From: rbibb(at)tomet.net

To: rv10-list(at)matronics.com

Subject: RE: RV10-List: Ram Air Oil Cooler Inlet - input requested

Date: Mon C 28 Sep 2009 08:57:21 -0500

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Well I wasn’t thinking of mounting the oil cooler on the cowl just deriving the source of air for the cooler (mounting in stock location but perhaps modified mount to reflect change in air source geometry) from a combined induction/oil cooler inlet.  The idea is to eliminate the source of air for the oil cooer from the rear of the baffles (whether inside a plenum or not) as to increase cooling air for the cylinders.  That creates the problem of creating an air source for the cooler.  Rather than create a separate inlet I was thinking of creating a larger “mouth”  on the below-cowl scoop for the induction and creating some sort of flow divider to send some air to the inlet and some to the cooler.   

Not being educated in fluid dynamics I’m looking for general guidelines as to an efficient method of engineering such an inlet/splitter combo. 

Thanks for the warning….. 

Richard Bibb 

972-771-2598 

972-835-5979 mobile 

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

Sent: Monday C September 28 C 2009 7:42 AM

To: rv10-list(at)matronics.com

Subject: Re: Ram Air Oil Cooler Inlet - input requested

Caution C my current aircraft has an oil cooler mounted on the lower cowling C not much lower than where Robin's inlet is located. Unfortunately C the manufacturer did no testing of that location C and in a climb it is enough of a low pressure area that flow can actually reverse C passing from cylinder bottoms out the oil cooler. Not good C and most every example I know of runs 210-215 oil temps. The only solution is for my aircraft is to relocate the oil cooler to the rear top of the engine baffling. I suppose what really needs examining is whether the engine air outlet is large enough or could benefit from cowl flaps. It is unfortunate that the prototypes didn't get any testing in AZ or TX to optimize engine cooling.  

On Mon C Sep 28 C 2009 at 7:23 AM C Richard Bibb <rbibb(at)tomet.net (rbibb(at)tomet.net)> wrote:   In following the thread on the James Plenum and various others with cooling problems I have been thinking about potential alternatives for my RV-10 setup (it’s down the road as I’m just starting main fuselage).

 For the aerodynamicists out there:  How would a larger intake scoop that had in internal split to feed intake air as well as oil cooler input work IYHO?  I’m thinking making the inlet a large affair that has a flow divider to send air into the FI body and a separate path (via flex hose) to the Oil Cooler C  This allows the plenum to concentrate on supplying cooling air to the cylinders without having any flow diverted to the oil cooler.  Similar to Robin Marks approach shown below but

 	  Quote: 	
		    http://www.matronics.com/Navigator?RV10-Listhttp://forums.matronics.com  	
0 	  Quote: 	

1 	  Quote: 	

2

 	  Quote: 	

3 		 	   		  Hotmail® has ever-growing storage! Don’t worry about storage limits. Check it out.  [quote][b]

AV8ORJWC

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

Posted: Mon Sep 28, 2009 8:22 am Post subject: Ram Air Oil Cooler Inlet - input requested

Exit flows.  Delta P seems to be the most productive area of pursuit.

Get the low pressure lower cowl more efficient at extraction - both the

plenum air and the exhaust gases.



John Cox - a LoPresti follower and fan of Fred Moreno's reports.



--

Nick Leonard

Joined: 18 Jun 2007
Posts: 35
Location: Sacramento, CA

Posted: Mon Sep 28, 2009 8:23 am Post subject: Re: Ram Air Oil Cooler Inlet - input requested

This is an interesting discussion.  I have a friend (Bob Cole) with an RV-6 that has done some extensive modifications to his cowling and I plan to follow in his footsteps.  Let me tell you a little about Bob.  He couldn't get the performance that he expected from the Katto prop he had made so he learned about prop design and manufacturing and made his own.  He is on his fourth 'tweak' (prop) and has it just about what he considers perfect.  He decided to build his own exhaust system so he learned about designing balanced flow exhaust systems and made his own.  He has since made several further modifications to further improve the performance and keeps working on the next knot of speed, degree of cooling, etc.  In each case he gets a base line measurement of performance before he makes his changes (they don't all make it better).



So about improving cooling.  Bob's approach has been to use an airspeed indicator to measure the change in the differential air pressure before and after any airflow modifications.  He simply runs the indicator tubes to the front and back of the testing area, gets a baseline and checks again after the change.  Like many others, he found that reducing the air inlet area on the cowling improved the air flow through the cowling.  Something about air being damned up in that area when the opening is too large, which is typical of the Van's design.  He also worked on getting the air out more effectively with a ramp on the back of the cowl. One of the things that made a big difference for him was to pay special attention on making sure that the seal to the engine baffling was 100% effective (no leaks).  It is the simple things that can make the biggest difference.



I saw how much information you can get from the measurement of the differential pressure (air speed indicator) throughout the engine area that I installed a small device from Honeywell (sourced from Allied Electronics) that will allow me to electronically do what Bob has done without having to run the tubes through the firewall (2-wires).  I expect to make various modification to the -10 for cooling efficiency, etc. (not flying yet). 



The bottom line to this conversation is that getting more air into the cowling is often more of a problem than a solution.  Also, get a good baseline measurement before you make any changes.  And also to thank the Bob's of the world for their curiosity, intelligence, gumption and incredible talent.

_________________
Nick Leonard
RV-10 (40015) Flying

AV8ORJWC

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

Posted: Mon Sep 28, 2009 8:41 am Post subject: Ram Air Oil Cooler Inlet - input requested

High angles of attack coupled with higher ambient temperatures certainly would have skewed the design results.  Being in the Northern climate and cooler temperature your idea holds strong merit.  Too bad a great design could not be reconsidered by the Parts Manufacturer.  

   

Much of the trailblazing is being done by the great group of "Early Adapters" south of the Oregon border.  

   

John - Aurora, OR  

     

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

 Sent: Monday, September 28, 2009 5:42 AM

 To: rv10-list(at)matronics.com

 Subject: Re: Ram Air Oil Cooler Inlet - input requested  

  

   

Caution, my current aircraft has an oil cooler mounted on the lower cowling, not much lower than where Robin's inlet is located. Unfortunately, the manufacturer did no testing of that location, and in a climb it is enough of a low pressure area that flow can actually reverse, passing from cylinder bottoms out the oil cooler. Not good, and most every example I know of runs 210-215 oil temps. The only solution is for my aircraft is to relocate the oil cooler to the rear top of the engine baffling. I suppose what really needs examining is whether the engine air outlet is large enough or could benefit from cowl flaps. It is unfortunate that the prototypes didn't get any testing in AZ or TX to optimize engine cooling.    

On Mon, Sep 28, 2009 at 7:23 AM, Richard Bibb <rbibb(at)tomet.net (rbibb(at)tomet.net)> wrote:      

In following the thread on the James Plenum and various others with cooling problems I have been thinking about potential alternatives for my RV-10 setup (it’s down the road as I’m just starting main fuselage).  

   

For the aerodynamicists out there:  How would a larger intake scoop that had in internal split to feed intake air as well as oil cooler input work IYHO?  I’m thinking making the inlet a large affair that has a flow divider to send air into the FI body and a separate path (via flex hose) to the Oil Cooler,  This allows the plenum to concentrate on supplying cooling air to the cylinders without having any flow diverted to the oil cooler.  Similar to Robin Marks approach shown below but  

  

  

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

carl.froehlich(at)verizon
Guest

Posted: Mon Sep 28, 2009 8:41 am Post subject: Ram Air Oil Cooler Inlet - input requested

I'll venture into the oil cooler mount/high temp waters with some thoughts:

1.  There was a good article a few months back in one of the kit magazines

on cooling air flow into the engine.  The bottom line is once the top of the

cowl (or plenum) is pressurized, the cylinder airflow (lbm/hr) is fairly

uniform.  My take from this is the air coming off the back for the oil

cooler does not affect one side more than the other.

2.  This article also discussed the relatively high pressure area at the

front top of the cowl caused by air bouncing off the rear baffle.  The

lesson learned is make sure the front cowl seal is in good shape.

3.  The third take away from the article is huge gain received from

smoothing the cowl air inlet passages.  For the James cowl this is done by

design.  For the Van's cowl this is done by adding the top cowl inlet ramps.

4.  While the standard Van's mount has clear advantage for installation

ease, I can't see how multiple redirections of air flow can go any good.  I

am not using this standard oil cooler mount in my project.

5.  Talking with others, I get the impression that the mid/aft cowl region

is a relatively high pressure area.  This would contribute to a lower

differential pressure across the oil cooler (in the standard mount) and thus

lower air flow.

6.  The other heat problem I see are the cabin heat valves.  As they are

shut on hot days, the more than ample heat muff hot air bounces off the

closed valves directly toward the fuel pump.  In addition to heating the

wrong component, I would guess this additional air pressure in the aft mid

cowl region contributes to the less than adequate differential pressure

across the oil cooler in the standard mount.  



What I'm doing:

1.  Using the James Cowl and plenum

2.  Mounting the oil cooler aft of the rear baffle with a direct connection

for air flow. 

3.  Mounted Cool Mat between the cabin heat valves and over the top and

front of the valves.  The objective is to isolate radiant heat from the

firewall and tunnel and redirect the unused hot air down toward the bottom

of the cowl.



Carl Froehlich

RV-8A (500 hrs)

RV-10 (fuselage make it pretty fiberglass work)



--

jdriggs49(at)msn.com
Guest

Posted: Mon Sep 28, 2009 10:45 am Post subject: Ram Air Oil Cooler Inlet - input requested

"I installed a small device from Honeywell (sourced from Allied Electronics) that will allow me to electronically"......could you be a bit more specific about this device. Sounds like something I need to look at. Very interesting discussion! Dan 

 	  Quote: 	
		   Subject: Re: Ram Air Oil Cooler Inlet - input requested

 From: nick(at)nleonard.com

 Date: Mon C 28 Sep 2009 09:23:36 -0700

 To: rv10-list(at)matronics.com

 --> RV10-List message posted by: "Nick Leonard" <nick(at)nleonard.com>

 This is an interesting discussion. I have a friend (Bob Cole) with an RV-6 that has done some extensive modifications to his cowling and I plan to follow in his footsteps. Let me tell you a little about Bob. He couldn't get the performance that he expected from the Katto prop he had made so he learned about prop design and manufacturing and made his own. He is on his fourth 'tweak' (prop) and has it just about what he considers perfect. He decided to build his own exhaust system so he learned about designing balanced flow exhaust systems and made his own. He has since made several further modifications to further improve the performance and keeps working on the next knot of speed C degree of cooling C etc. In each case he gets a base line measurement of performance before he makes his changes (they don't all make it better).

 So about improving cooling. Bob's approach has been to use an airspeed indicator to measure the change in the differential air pressure before and after any airflow modifications. He simply runs the indicator tubes to the front and back of the testing area C gets a baseline and checks again after the change. Like many others C he found that reducing the air inlet area on the cowling improved the air flow through the cowling. Something about air being damned up in that area when the opening is too large C which is typical of the Van's design. He also worked on getting the air out more effectively with a ramp on the back of the cowl. One of the things that made a big difference for him was to pay special attention on making sure that the seal to the engine baffling was 100% effective (no leaks). It is the simple things that can make the biggest difference.

 I saw how much information you can get from the measurement of the differential pressure (air speed indicator) throughout the engine area that I installed a small device from Honeywell (sourced from Allied Electronics) that will allow me to electronically do what Bob has done without having to run the tubes through the firewall (2-wires). I expect to make various modification to the -10 for cooling efficiency C etc. (not flying yet). 

 The bottom line to this conversation is that getting more air into the cowling is often more of a problem than a solution. Also C get a good baseline measurement before you make any changes. And also to thank the Bob's of the world for their curiosity C intelligence C gumption and incredible talent.

 --------

 Nick Leonard

 RV-10 (40015) Finish

 Read this topic online here:

 http://forums.matronics.com/viewtopic.php?p=265331#265331

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Deems Davis

Joined: 09 Jan 2006
Posts: 925

Posted: Mon Sep 28, 2009 12:03 pm Post subject: Ram Air Oil Cooler Inlet - input requested

This is a familiar topic.               I have the James cowl/Plenum, 

Live in AZ and have to deal with heat issues (Today's high will reach 

107!). I have been through several machinations in an attempt to deal 

with heat. Ton's of louvers on bottom of cowl, increasing the lower cowl 

exit area 5-10%. Plenum rework, baffle sealing. I still have the oil 

cooler mounted in the stock (Van's) location. My current temps are 

'manageable'. Everything is linked directly to OAT, the cooler the 

better. With OAT of  approx 90-95, On Take Off, I will see Oil temps 

climb to 210-215 if I keep airspeed up to 120-130 kts. Hottest cyls CHT 

seem to peak (at) 400-405. At altitude oil temps come back to 195 and CHT 

to 360-380. On our trip back east (ie. cooler temps) we saw oil temps 

175-185. I consider my temperatures on the high side, but am worried 

about overreacting until I get some more experience in some lower 

temperatures.

One approach I have considered is relocating the oil cooler to behind 

the baffle (#6 likely). Initially I didn't think there was enough room, 

however I saw an installation on an F1 Rocket

http://www.pflanzer-aviation.com/Engine9.html which got me thinking, I 

borrowed an unmounted oil cooler and did a loose test fit and I think it 

could be made to work.



Deems Davis

www.deemsrv10.com

N519PJ



Carl Froehlich wrote:

[quote] 



 I'll venture into the oil cooler mount/high temp waters with some thoughts:

 1.  There was a good article a few months back in one of the kit magazines

 on cooling air flow into the engine.  The bottom line is once the top of the

 cowl (or plenum) is pressurized, the cylinder airflow (lbm/hr) is fairly

 uniform.  My take from this is the air coming off the back for the oil

 cooler does not affect one side more than the other.

 2.  This article also discussed the relatively high pressure area at the

 front top of the cowl caused by air bouncing off the rear baffle.  The

 lesson learned is make sure the front cowl seal is in good shape.

 3.  The third take away from the article is huge gain received from

 smoothing the cowl air inlet passages.  For the James cowl this is done by

 design.  For the Van's cowl this is done by adding the top cowl inlet ramps.

 4.  While the standard Van's mount has clear advantage for installation

 ease, I can't see how multiple redirections of air flow can go any good.  I

 am not using this standard oil cooler mount in my project.

 5.  Talking with others, I get the impression that the mid/aft cowl region

 is a relatively high pressure area.  This would contribute to a lower

 differential pressure across the oil cooler (in the standard mount) and thus

 lower air flow.

 6.  The other heat problem I see are the cabin heat valves.  As they are

 shut on hot days, the more than ample heat muff hot air bounces off the

 closed valves directly toward the fuel pump.  In addition to heating the

 wrong component, I would guess this additional air pressure in the aft mid

 cowl region contributes to the less than adequate differential pressure

 across the oil cooler in the standard mount.  



 What I'm doing:

 1.  Using the James Cowl and plenum

 2.  Mounting the oil cooler aft of the rear baffle with a direct connection

 for air flow. 

 3.  Mounted Cool Mat between the cabin heat valves and over the top and

 front of the valves.  The objective is to isolate radiant heat from the

 firewall and tunnel and redirect the unused hot air down toward the bottom

 of the cowl.



 Carl Froehlich

 RV-8A (500 hrs)

 RV-10 (fuselage make it pretty fiberglass work)



 --

bwestfall

Joined: 22 Oct 2008
Posts: 131
Location: Portland, OR

Posted: Mon Sep 28, 2009 12:57 pm Post subject: Ram Air Oil Cooler Inlet - input requested

I've often wondered if a more direct route to the airflow would help the oil

cooler.  Would this location give enough room for "exhausting" the hot air?

I wonder what it would do pressure wise for air behind the baffling?



I sure wish somebody would figure this out .



Ben Westfall

Portland, OR

#40579

--

pitts_pilot(at)bellsouth.
Guest

Posted: Mon Sep 28, 2009 1:01 pm Post subject: Ram Air Oil Cooler Inlet - input requested

I've been interested in the oil cooler thread ...... because I'll be 

there someday!  One other poster measured the pressures across the 

cooler, but I couldn't find it .... anyway my thoughts were a plenum on 

the output side to deflect the air towards the lower cowl outlet .... or 

   a dedicated louver ..... instead of just letting it blow into the 

pressurized lower cowl.

Linn

do not archive

Deems Davis wrote:

[quote] 

 This is a familiar topic.               I have the James cowl/Plenum, 

 Live in AZ and have to deal with heat issues (Today's high will reach 

 107!). I have been through several machinations in an attempt to deal 

 with heat. Ton's of louvers on bottom of cowl, increasing the lower cowl 

 exit area 5-10%. Plenum rework, baffle sealing. I still have the oil 

 cooler mounted in the stock (Van's) location. My current temps are 

 'manageable'. Everything is linked directly to OAT, the cooler the 

 better. With OAT of  approx 90-95, On Take Off, I will see Oil temps 

 climb to 210-215 if I keep airspeed up to 120-130 kts. Hottest cyls CHT 

 seem to peak (at) 400-405. At altitude oil temps come back to 195 and CHT 

 to 360-380. On our trip back east (ie. cooler temps) we saw oil temps 

 175-185. I consider my temperatures on the high side, but am worried 

 about overreacting until I get some more experience in some lower 

 temperatures.

 One approach I have considered is relocating the oil cooler to behind 

 the baffle (#6 likely). Initially I didn't think there was enough room, 

 however I saw an installation on an F1 Rocket

 http://www.pflanzer-aviation.com/Engine9.html which got me thinking, I 

 borrowed an unmounted oil cooler and did a loose test fit and I think it 

 could be made to work.

 Deems Davis

 www.deemsrv10.com

 N519PJ

 Carl Froehlich wrote:

> 

> <carl.froehlich(at)verizon.net>

>

> I'll venture into the oil cooler mount/high temp waters with some 

> thoughts:

> 1.  There was a good article a few months back in one of the kit 

> magazines

> on cooling air flow into the engine.  The bottom line is once the top 

> of the

> cowl (or plenum) is pressurized, the cylinder airflow (lbm/hr) is fairly

> uniform.  My take from this is the air coming off the back for the oil

> cooler does not affect one side more than the other.

> 2.  This article also discussed the relatively high pressure area at the

> front top of the cowl caused by air bouncing off the rear baffle.  The

> lesson learned is make sure the front cowl seal is in good shape.

> 3.  The third take away from the article is huge gain received from

> smoothing the cowl air inlet passages.  For the James cowl this is 

> done by

> design.  For the Van's cowl this is done by adding the top cowl inlet 

> ramps.

> 4.  While the standard Van's mount has clear advantage for installation

> ease, I can't see how multiple redirections of air flow can go any 

> good.  I

> am not using this standard oil cooler mount in my project.

> 5.  Talking with others, I get the impression that the mid/aft cowl 

> region

> is a relatively high pressure area.  This would contribute to a lower

> differential pressure across the oil cooler (in the standard mount) 

> and thus

> lower air flow.

> 6.  The other heat problem I see are the cabin heat valves.  As they are

> shut on hot days, the more than ample heat muff hot air bounces off the

> closed valves directly toward the fuel pump.  In addition to heating the

> wrong component, I would guess this additional air pressure in the aft 

> mid

> cowl region contributes to the less than adequate differential pressure

> across the oil cooler in the standard mount. 

> What I'm doing:

> 1.  Using the James Cowl and plenum

> 2.  Mounting the oil cooler aft of the rear baffle with a direct 

> connection

> for air flow. 3.  Mounted Cool Mat between the cabin heat valves and 

> over the top and

> front of the valves.  The objective is to isolate radiant heat from the

> firewall and tunnel and redirect the unused hot air down toward the 

> bottom

> of the cowl.

>

> Carl Froehlich

> RV-8A (500 hrs)

> RV-10 (fuselage make it pretty fiberglass work)

>

> --

Deems Davis

Joined: 09 Jan 2006
Posts: 925

Posted: Mon Sep 28, 2009 1:58 pm Post subject: Ram Air Oil Cooler Inlet - input requested

I tried that. ........didn't help 

http://deemsrv10.com/album/Phase1/slides/DSC07522.html



Deems



Linn Walters wrote:

[quote] 



 I've been interested in the oil cooler thread ...... because I'll be 

 there someday!  One other poster measured the pressures across the 

 cooler, but I couldn't find it .... anyway my thoughts were a plenum 

 on the output side to deflect the air towards the lower cowl outlet 

 .... or   a dedicated louver ..... instead of just letting it blow 

 into the pressurized lower cowl.

 Linn

 do not archive

 Deems Davis wrote:

> 

>

> This is a familiar topic.               I have the James 

> cowl/Plenum, Live in AZ and have to deal with heat issues (Today's 

> high will reach 107!). I have been through several machinations in an 

> attempt to deal with heat. Ton's of louvers on bottom of cowl, 

> increasing the lower cowl exit area 5-10%. Plenum rework, baffle 

> sealing. I still have the oil cooler mounted in the stock (Van's) 

> location. My current temps are 'manageable'. Everything is linked 

> directly to OAT, the cooler the better. With OAT of  approx 90-95, On 

> Take Off, I will see Oil temps climb to 210-215 if I keep airspeed up 

> to 120-130 kts. Hottest cyls CHT seem to peak (at) 400-405. At altitude 

> oil temps come back to 195 and CHT to 360-380. On our trip back east 

> (ie. cooler temps) we saw oil temps 175-185. I consider my 

> temperatures on the high side, but am worried about overreacting 

> until I get some more experience in some lower temperatures.

> One approach I have considered is relocating the oil cooler to behind 

> the baffle (#6 likely). Initially I didn't think there was enough 

> room, however I saw an installation on an F1 Rocket

> http://www.pflanzer-aviation.com/Engine9.html which got me thinking, 

> I borrowed an unmounted oil cooler and did a loose test fit and I 

> think it could be made to work.

>

> Deems Davis

> www.deemsrv10.com

> N519PJ

>

> Carl Froehlich wrote:

>> 

>> <carl.froehlich(at)verizon.net>

>>

>> I'll venture into the oil cooler mount/high temp waters with some 

>> thoughts:

>> 1.  There was a good article a few months back in one of the kit 

>> magazines

>> on cooling air flow into the engine.  The bottom line is once the 

>> top of the

>> cowl (or plenum) is pressurized, the cylinder airflow (lbm/hr) is 

>> fairly

>> uniform.  My take from this is the air coming off the back for the oil

>> cooler does not affect one side more than the other.

>> 2.  This article also discussed the relatively high pressure area at 

>> the

>> front top of the cowl caused by air bouncing off the rear baffle.  The

>> lesson learned is make sure the front cowl seal is in good shape.

>> 3.  The third take away from the article is huge gain received from

>> smoothing the cowl air inlet passages.  For the James cowl this is 

>> done by

>> design.  For the Van's cowl this is done by adding the top cowl 

>> inlet ramps.

>> 4.  While the standard Van's mount has clear advantage for installation

>> ease, I can't see how multiple redirections of air flow can go any 

>> good.  I

>> am not using this standard oil cooler mount in my project.

>> 5.  Talking with others, I get the impression that the mid/aft cowl 

>> region

>> is a relatively high pressure area.  This would contribute to a lower

>> differential pressure across the oil cooler (in the standard mount) 

>> and thus

>> lower air flow.

>> 6.  The other heat problem I see are the cabin heat valves.  As they 

>> are

>> shut on hot days, the more than ample heat muff hot air bounces off the

>> closed valves directly toward the fuel pump.  In addition to heating 

>> the

>> wrong component, I would guess this additional air pressure in the 

>> aft mid

>> cowl region contributes to the less than adequate differential pressure

>> across the oil cooler in the standard mount. What I'm doing:

>> 1.  Using the James Cowl and plenum

>> 2.  Mounting the oil cooler aft of the rear baffle with a direct 

>> connection

>> for air flow. 3.  Mounted Cool Mat between the cabin heat valves and 

>> over the top and

>> front of the valves.  The objective is to isolate radiant heat from the

>> firewall and tunnel and redirect the unused hot air down toward the 

>> bottom

>> of the cowl.

>>

>> Carl Froehlich

>> RV-8A (500 hrs)

>> RV-10 (fuselage make it pretty fiberglass work)

>>

>> --

Nick Leonard

Joined: 18 Jun 2007
Posts: 35
Location: Sacramento, CA

Posted: Mon Sep 28, 2009 1:59 pm Post subject: Re: Ram Air Oil Cooler Inlet - input requested

[quote="jdriggs49(at)msn.com"]"I installed a small device from Honeywell (sourced from Allied Electronics) that will allow me to electronically"......could you be a bit more specific about this device. Sounds like something I need to look at. Very interesting discussion! Danï¿½



Dan,



The device is the Honeywell DCXL30DS.  Here is the spec sheet from Allied..

https://www.alliedelec.com/Images/Products/Datasheets/BM/HONEYWELL_SENSYM_ICT/643-0213.PDF

I plan on capturing the data with a simple USB data logger such as the EL-USB-3 which will provide a time stamp that I hope to link with the glass panel (AFS 4500) flight log info. 

http://www.dataq.com/support/documentation/pdf/datasheets/el-data-logger.pdf

When I need to measure the effectiveness of anything (air inlet openings, outlets, oil cooler, etc) I will connect the tubes to the unit and the logger at the other end.  Any changes I make should be easily measured with this set up.  I could carry a small PC and see the results in real time.



Nickï¿½

 	  Quote: 	
		   Subject: Re: Ram Air Oil Cooler Inlet - input requested

 From: nick(at)nleonard.com

 Date: Mon C 28 Sep 2009 09:23:36 -0700

 To: rv10-list(at)matronics.com

 

 --> RV10-List message posted by: "Nick Leonard" <nick>

 

 This is an interesting discussion. I have a friend (Bob Cole) with an RV-6 that has done some extensive modifications to his cowling and I plan to follow in his footsteps. Let me tell you a little about Bob. He couldn't get the performance that he expected from the Katto prop he had made so he learned about prop design and manufacturing and made his own. He is on his fourth 'tweak' (prop) and has it just about what he considers perfect. He decided to build his own exhaust system so he learned about designing balanced flow exhaust systems and made his own. He has since made several further modifications to further improve the performance and keeps working on the next knot of speed C degree of cooling C etc. In each case he gets a base line measurement of performance before he makes his changes (they don't all make it better).

 

 So about improving cooling. Bob's approach has been to use an airspeed indicator to measure the change in the differential air pressure before and after any airflow modifications. He simply runs the indicator tubes to the front and back of the testing area C gets a baseline and checks again after the change. Like many others C he found that reducing the air inlet area on the cowling improved the air flow through the cowling. Something about air being damned up in that area when the opening is too large C which is typical of the Van's design. He also worked on getting the air out more effectively with a ramp on the back of the cowl. One of the things that made a big difference for him was to pay special attention on making sure that the seal to the engine baffling was 100% effective (no leaks). It is the simple things that can make the biggest difference.

 

 I saw how much information you can get from the measurement of the differential pressure (air speed indicator) throughout the engine area that I installed a small device from Honeywell (sourced from Allied Electronics) that will allow me to electronically do what Bob has done without having to run the tubes through the firewall (2-wires). I expect to make various modification to the -10 for cooling efficiency C etc. (not flying yet). 

 

 The bottom line to this conversation is that getting more air into the cowling is often more of a problem than a solution. Also C get a good baseline measurement before you make any changes. And also to thank the Bob's of the world for their curiosity C intelligence C gumption and incredible talent.

 

 --------

 Nick Leonard

 RV-10 (40015) Finish

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=265331#265331

 

 = Archive Search & Download C 7-Day Browse C Chat C FAQ C

&g===

	


 	  Quote: 	
		   

 

 

 		 	   		  Microsoft brings you a new way to search the web. Try  Bingï¿½ now   	  Quote: 	
		  [b]

_________________
Nick Leonard
RV-10 (40015) Flying

pitts_pilot(at)bellsouth.
Guest

Posted: Mon Sep 28, 2009 2:31 pm Post subject: Ram Air Oil Cooler Inlet - input requested

I was thinking more enclosed.  If the pressure differential isn't great, 

exhausting the oil cooler air into the lower cowl just won't have much 

air flow.  I'm having trouble putting my 'concept' into words!  If you 

have a plenum over the engine .... with no leaks around the engine ..... 

all the air coming into the plenum exhausts into the lower cowl.  The 

pressure differential is the drop across the engine.    believe that if 

the pressure difference is zero, you have the lowest cooling drag ..... 

what goes in goes out easily.  With the oil cooler fed from the plenum, 

and no pressure drop across the engine, then there is no air flow 

through the cooler.  Ducting the entire oil cooler air into the ramp 

next to the opening should have some venturi effect and increase the 

negative pressure on the hot air.  Does this make any sense???  Have I 

gone off into another reality here????

Linn

do not archive

 	  Quote: 	

 I tried that. ........didn't help 

 http://deemsrv10.com/album/Phase1/slides/DSC07522.html

 Deems

 Linn Walters wrote:

> 

>

> I've been interested in the oil cooler thread ...... because I'll be 

> there someday!  One other poster measured the pressures across the 

> cooler, but I couldn't find it .... anyway my thoughts were a plenum 

> on the output side to deflect the air towards the lower cowl outlet 

> .... or   a dedicated louver ..... instead of just letting it blow 

> into the pressurized lower cowl.

> Linn

> do not archive

> Deems Davis wrote:

>>

Lenny Iszak

Joined: 23 Mar 2008
Posts: 270

Posted: Mon Sep 28, 2009 2:45 pm Post subject: Re: Ram Air Oil Cooler Inlet - input requested

I'm using an MPX5050DP in my speed sensitive trim controller and it appears to be working fine, although not flight tested yet. It's cheaper at $10.34. I read it with an arduino.



http://www.mouser.com/ProductDetail/Freescale-Semiconductor/MPX5050DP/?qs=r8OyiFxb6RdEZ0vCbPdH8w%3d%3d



Since the arduino has plenty of analog ports, i was thinking to hook up a few of these sensors and get DP readings from multiple locations at the same time.



Lenny

speckter(at)comcast.net
Guest

Posted: Mon Sep 28, 2009 2:49 pm Post subject: Ram Air Oil Cooler Inlet - input requested

In reality there is a pressure differential from the top of the cylinders to

the bottom.  Lycoming recommends I think 6" in order to achieve proper

cooling.  I don't know of we are seeing that in the 10.  More things to

check out.



Gary Specketer



--

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