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James Cowl & plenum

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CJohnston(at)popsound.com
Guest

Posted: Mon Jan 15, 2007 12:16 pm Post subject: James Cowl & plenum

Hey Deems - 



Are you using the plenum?  I've not really decided, and was wondering if

others had thoughts about it.  I don't know much about the mechanics of

it, but it seems like it'd improve cooling etc.  Also it (I guess) would

reduce stress on the cowl and attachments, as the plenum is pressurized

and not the entire cowl.  Am I incorrect here?  What about inspecting

the engine through the oil filler hole?  You wouldn't see the top of the

engine there - is that a bummer?  Also, doesn't the engine get hot where

it gets close to the plenum?  Is this a problem?  I'd love any info

before I go calling Sam about it.



cj

#40410

fuse

www.perfectlygoodairplane.net



--

Deems Davis

Joined: 09 Jan 2006
Posts: 925

Posted: Mon Jan 15, 2007 1:36 pm Post subject: James Cowl & plenum

This may be a case of the blind leading the blind, but here's what I've 

learned.



Apart form aesthetics, the main reason for my going with the James cowl 

& plenum was performance. there are no RV-10'd flying with it yet so 

performance improvements are subjective. However there are enough RV 6.7 

& 8's flying with them to indicate that the combination produces 

anywhere between 5-10 mph. It would take a LOT of additional HP to get 

the kind of an improvement.



The biggest portion of the improvement is attributable to the Plenum. I 

don't begin to understand all of the fluid dynamic physics, but as Sam 

explained to me, the 'secret is: with Wills cowl rings you get 32 sq 

inchs of air entering the plenum, and you want 32 sq inches of area 

around the bottom of the clys for the air to exit the 'pressurized' 

portion. an imbalance with more air coming in than exiting results in 

drag with the air going back out the front of the cowl. The advantages 

of the plenum are that there is no 'leakage' between the baffling and 

the top of the cowl. some measurements have indicated that as much as 

50% of the  cooling air can be lost through what otherwise appears to be 

a tight fit between baffling material and the cowl.  the leakage also 

contributed to increased drag. Sam's  cowl comes with templates for his 

own baffling that mates to his cowl. His baffling templates are designed 

to equalize/optimize the air entering the plenum and the air exiting. 

Some builders have used Van's baffling kit and adapted it to Sam's 

plenum, Sam strongly cautioned me against this, believing it was a 

source of problems with the fitment of the plenum, and also with the 

balance of the air flow. he quoted me the numbers on van's baffles and 

the area around the bottom of each cyl was larger than the area he 

designed in his plans. Another benefit of a properly functioning 

plenum/baffle combo it better balanced cooling between cyls. I believe 

the Sam indicates that  cyl temps with his plenum should not vary by 

more than 2% (!).



I've spoken w/ 2 -10 builders that had problems fitting Sam's plenum. 

both used Van's baffle kit. I almost skipped ordering a plenum based on 

their troubles. to Sam's credit, he remade plenums for both builders and 

sent them at his expense. One builder seems satisfied and one isn't. I 

spoke with both Will and Sam about the fittment situation, and they 

called the builders and talked with additional builders and concluded 

that the problems were most likely due to using Van's baffling. Will 

told me " if you order one of our products and it doesn't work as it is 

supposed to we will stay with you until it does"



So,  Yes I have ordered Sam's Plenum,



Access (easy) to the top of the engine is a drawback of the plenum, ans 

it derives its benefits from a 'hard' mounting to the baffling. (I've 

got these pretty polished induction tubes, color coordinated plug wires, 

custom painted crankcase, chrome valve covers, and it's all going to get 

covered up. (I just remind myself that 5-10 mph is worth it!). The 

epoxy/glass that Sam used is designed for the temps of the engine 

compartment.



Deems Davis # 406

Finishing - ( A Misnomer ! )

http://deemsrv10.com/



Chris Johnston wrote:



[quote]



Hey Deems - 



Are you using the plenum?  I've not really decided, and was wondering if

others had thoughts about it.  I don't know much about the mechanics of

it, but it seems like it'd improve cooling etc.  Also it (I guess) would

reduce stress on the cowl and attachments, as the plenum is pressurized

and not the entire cowl.  Am I incorrect here?  What about inspecting

the engine through the oil filler hole?  You wouldn't see the top of the

engine there - is that a bummer?  Also, doesn't the engine get hot where

it gets close to the plenum?  Is this a problem?  I'd love any info

before I go calling Sam about it.



cj

#40410

fuse

www.perfectlygoodairplane.net



--

ddddsp1(at)juno.com
Guest

Posted: Mon Jan 15, 2007 3:49 pm Post subject: James Cowl & plenum

Deems, 

I never realized you were so interested in SPEED.  Are you gonna race at RENO with your 10?  I bet you are gonna race John Cox in 2020 when he gets his RV10 done...............   Haven't people told you that at our age we are suppose to SLOW DOWN.  You are retired....you don't have to get there 20 minutes early.  Seriously though, that plenum setup sounds really ideal and will hopefully give you the speed and cooling that has eluded some RV10 builders.  You will be breaking new ground when you start flying.  Hope you are ready for the POSTS from all the EXPERTS on this list telling you your numbers CAN"T be real. 

Keep sanding that fiberglass! 

DEAN 40449 



________________________________________________________________________

 FREE Reminder Service  - NEW from AmericanGreetings.com

 Click HERE and never forget a Birthday or Anniversary again!

    [quote][b]

n8vim(at)arrl.net
Guest

Posted: Mon Jan 15, 2007 3:58 pm Post subject: James Cowl & plenum

Hey,

    You'll slow down upon impact....   until then, Go Speed Racer Go!



-Jim do not archive



ddddsp1(at)juno.com wrote:



 	  Quote: 	
		   Deems,



 I never realized you were so interested in SPEED.  Are you gonna race 

 at RENO with your 10?  I bet you are gonna race John Cox in 2020 when 

 he gets his RV10 done...............   Haven't people told you that 

 at our age we are suppose to SLOW DOWN.  You are retired....you don't 

 have to get there 20 minutes early.  Seriously though, that plenum 

 setup sounds really ideal and will hopefully give you the speed and 

 cooling that has eluded some RV10 builders.  You will be breaking new 

 ground when you start flying.  Hope you are ready for the POSTS from 

 all the EXPERTS on this list telling you your numbers CAN"T be real.



 Keep sanding that fiberglass!



 DEAN 40449



 ________________________________________________________________________

 *FREE* Reminder Service - NEW from AmericanGreetings.com

 *Click HERE* and never forget a Birthday or Anniversary again! 

 <http://track.juno.com/s/lc?s=197335&u=http://www.americangreetings.com/products/online_calendar.pd?c=uol5752>



*

*

AV8ORJWC

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

Posted: Mon Jan 15, 2007 4:22 pm Post subject: James Cowl & plenum

Dean –   

   

Here is the gauntlet for 2007.  Knots not MPH.  200.00 cruise in a RV-10.  That’s head to head, over a defined course, same fuel load (60 US Gal).  Block to Block just like Nextel Nascar.  

   

Oh yeh, It’s going to fall out of the sky from flutter issues, I keep forgetting.  Less weight, Less drag, stronger construction, more efficient cooling, bigger grin.  My money is on Deems and that is in addition to all the beer that I owe Camp Condrey from such a pathetic showing of completed RVs at OSH last summer.  I am speculating that Deems will win it, cause he can read those gigantic OP technologies screens a millisecond quicker for engine tweaking.  

   

Anyone else of us old timers notice the similarity between Chris Johnson and James McClow.  Main difference is in his continual grin, that of his partner and the blazing progress he is making due to lack of spelling errors.  I think the secret is a passionate partner chasing the same goal in the same house.  

     

John Cox 

 the Turbanator #40600   

        

  

From: owner-rv10-list-server(at)matronics.com [mailto:owner-rv10-list-server(at)matronics.com] On Behalf Of ddddsp1(at)juno.com

 Sent: Monday, January 15, 2007 3:46 PM

 To: rv10-list(at)matronics.com

 Subject: Re: James Cowl & plenum  

  

   

Deems,  

I never realized you were so interested in SPEED.  Are you gonna race at RENO with your 10?  I bet you are gonna race John Cox in 2020 when he gets his RV10 done...............   Haven't people told you that at our age we are suppose to SLOW DOWN.  You are retired....you don't have to get there 20 minutes early.  Seriously though, that plenum setup sounds really ideal and will hopefully give you the speed and cooling that has eluded some RV10 builders.  You will be breaking new ground when you start flying.  Hope you are ready for the POSTS from all the EXPERTS on this list telling you your numbers CAN"T be real.  

Keep sanding that fiberglass!  

DEAN 40449  



 

 ________________________________________________________________________

 FREE Reminder Service - NEW from AmericanGreetings.com

 Click HERE and never forget a Birthday or Anniversary again!  [quote]   [b]

dmaib@me.com

Joined: 25 Apr 2006
Posts: 455
Location: New Smyrna Beach, Florida

Posted: Mon Jan 15, 2007 4:36 pm Post subject: James Cowl & plenum

Great information Deems. I am leaning towards the James cowl and  

plenum, so this is good info for me. One question. Does the James  

cowl fasten with camlocs or a hinge, or does it matter? I would like  

to use camlocs if possible.



David Maib

#40559



On Jan 15, 2007, at 3:35 PM, Deems Davis wrote:






This may be a case of the blind leading the blind, but here's what  

I've learned.



Apart form aesthetics, the main reason for my going with the James  

cowl & plenum was performance. there are no RV-10'd flying with it  

yet so performance improvements are subjective. However there are  

enough RV 6.7 & 8's flying with them to indicate that the combination  

produces anywhere between 5-10 mph. It would take a LOT of additional  

HP to get the kind of an improvement.



The biggest portion of the improvement is attributable to the Plenum.  

I don't begin to understand all of the fluid dynamic physics, but as  

Sam explained to me, the 'secret is: with Wills cowl rings you get 32  

sq inchs of air entering the plenum, and you want 32 sq inches of  

area around the bottom of the clys for the air to exit the  

'pressurized' portion. an imbalance with more air coming in than  

exiting results in drag with the air going back out the front of the  

cowl. The advantages of the plenum are that there is no 'leakage'  

between the baffling and the top of the cowl. some measurements have  

indicated that as much as 50% of the  cooling air can be lost through  

what otherwise appears to be a tight fit between baffling material  

and the cowl.  the leakage also contributed to increased drag. Sam's   

cowl comes with templates for his own baffling that mates to his  

cowl. His baffling templates are designed to equalize/optimize the  

air entering the plenum and the air exiting. Some builders have used  

Van's baffling kit and adapted it to Sam's plenum, Sam strongly  

cautioned me against this, believing it was a source of problems with  

the fitment of the plenum, and also with the balance of the air flow.  

he quoted me the numbers on van's baffles and the area around the  

bottom of each cyl was larger than the area he designed in his plans.  

Another benefit of a properly functioning plenum/baffle combo it  

better balanced cooling between cyls. I believe the Sam indicates  

that  cyl temps with his plenum should not vary by more than 2% (!).



I've spoken w/ 2 -10 builders that had problems fitting Sam's plenum.  

both used Van's baffle kit. I almost skipped ordering a plenum based  

on their troubles. to Sam's credit, he remade plenums for both  

builders and sent them at his expense. One builder seems satisfied  

and one isn't. I spoke with both Will and Sam about the fittment  

situation, and they called the builders and talked with additional  

builders and concluded that the problems were most likely due to  

using Van's baffling. Will told me " if you order one of our products  

and it doesn't work as it is supposed to we will stay with you until  

it does"



So,  Yes I have ordered Sam's Plenum,



Access (easy) to the top of the engine is a drawback of the plenum,  

ans it derives its benefits from a 'hard' mounting to the baffling.  

(I've got these pretty polished induction tubes, color coordinated  

plug wires, custom painted crankcase, chrome valve covers, and it's  

all going to get covered up. (I just remind myself that 5-10 mph is  

worth it!). The epoxy/glass that Sam used is designed for the temps  

of the engine compartment.



Deems Davis # 406

Finishing - ( A Misnomer ! )

http://deemsrv10.com/



Chris Johnston wrote:



[quote] 

 <CJohnston(at)popsound.com>



 Hey Deems -

 Are you using the plenum?  I've not really decided, and was  

 wondering if

 others had thoughts about it.  I don't know much about the  

 mechanics of

 it, but it seems like it'd improve cooling etc.  Also it (I guess)  

 would

 reduce stress on the cowl and attachments, as the plenum is  

 pressurized

 and not the entire cowl.  Am I incorrect here?  What about inspecting

 the engine through the oil filler hole?  You wouldn't see the top  

 of the

 engine there - is that a bummer?  Also, doesn't the engine get hot  

 where

 it gets close to the plenum?  Is this a problem?  I'd love any info

 before I go calling Sam about it.



 cj

 #40410

 fuse

 www.perfectlygoodairplane.net



 --

_________________
David Maib
RV-10 #40559
New Smyrna Beach, FL

Deems Davis

Joined: 09 Jan 2006
Posts: 925

Posted: Mon Jan 15, 2007 5:32 pm Post subject: James Cowl & plenum

I don't believe there's any restrictions on using camlocs. I haven't 

read through his plans, but I believe he assumes hinges, just like Van's.

I was also initially thinking about Camlocs, but after seeing some 

really well done hinge installations, I've decided to go that way.



David Maib wrote:



 	  Quote: 	
		   



 Great information Deems. I am leaning towards the James cowl and  

 plenum, so this is good info for me. One question. Does the James  

 cowl fasten with camlocs or a hinge, or does it matter? I would like  

 to use camlocs if possible.



 David Maib

 #40559

Deems Davis

Joined: 09 Jan 2006
Posts: 925

Posted: Mon Jan 15, 2007 5:53 pm Post subject: James Cowl & plenum

I'm really not a speed freak, I'm just stingy! I laid out enough $'s for 

this beautiful mass of precision machined parts, that I want to get all 

of my money's worth. Cleaning up drag, is like 'free hp'. So if you're 

going to go to the effort to build a nice plane you might as well get it 

to perform at it's optimum, I don't know if John's gauntlet of 200 KTS 

is achievable for this grasshopper,  perhaps, If I began from 5K ft and 

dove to 20 ft. above the Salton Sea, on a cold day in late Jan, and 

leveled off for a 2 mile speed trap, I might make it. But only time,  

and LOTs more F/G sanding/priming will tell 



Deems Davis # 406

Finishing - ( A Misnomer ! )

http://deemsrv10.com/



ddddsp1(at)juno.com wrote:



 	  Quote: 	
		   Deems,



 I never realized you were so interested in SPEED.  Are you gonna race 

 at RENO with your 10?  I bet you are gonna race John Cox in 2020 when 

 he gets his RV10 done...............   Haven't people told you that 

 at our age we are suppose to SLOW DOWN.  You are retired....you don't 

 have to get there 20 minutes early.  Seriously though, that plenum 

 setup sounds really ideal and will hopefully give you the speed and 

 cooling that has eluded some RV10 builders.  You will be breaking new 

 ground when you start flying.  Hope you are ready for the POSTS from 

 all the EXPERTS on this list telling you your numbers CAN"T be real.



 Keep sanding that fiberglass!



 DEAN 40449



 ________________________________________________________________________

 *FREE* Reminder Service - NEW from AmericanGreetings.com

 *Click HERE* and never forget a Birthday or Anniversary again! 

 <http://track.juno.com/s/lc?s=197335&u=http://www.americangreetings.com/products/online_calendar.pd?c=uol5752>



*

*

rvbuilder(at)sausen.net
Guest

Posted: Tue Jan 16, 2007 7:23 pm Post subject: James Cowl & plenum

On another note about James service, I was one of the first to get the

plenum for the IO-540 back around OSH.  It's been sitting in a box since

then because of my move and subsequent building out a new

workshop/hanger.  I heard a couple months ago about the fit problem but

decided to wait until I was to the point of needing it before calling

Sam.  He called me about two weeks ago to let me know about the problem

and that a new one was being shipped that day.  Luckily he called before

going to UPS or my plenum would be sitting at an abandoned workshop in

TX rather than with me in WI!



  Once upon a time Deems and I were about even and doing a lot of the

same things like engine, cowl, plenum, etc and I was the one doing a ton

of due diligence and explaining it to the list.  Gotta say I'm glad this

move is giving me a substantial break so Deems can have the steep

learning curve for a while!  Although if I would have known about my

little hiatus I could have willed him all of my slots as I have had the

engine and plenum since OSH and the cowl for almost two months.  

Can't wait for Deems to be flying as it's going to be like a preview of

mine.



Michael Sausen

-10 #352 limbo



--

LarryRosen

Joined: 16 Jan 2006
Posts: 415
Location: Medford, NJ

Posted: Tue Jan 16, 2007 7:39 pm Post subject: James Cowl & plenum

I was also at the same point in the build as you were Michael before you 

move.  Deemes has speed by me (summer was tough with all the family 

stuff getting in the way of building   Now I am just in front of you 

and watching and learning from Deemes.



Deemes, keep it up, keep posting to your web site.  It is helping all of us.



Larry

#356 (4 behind Michael)



RV Builder (Michael Sausen) wrote:

[quote] 



   On another note about James service, I was one of the first to get the

 plenum for the IO-540 back around OSH.  It's been sitting in a box since

 then because of my move and subsequent building out a new

 workshop/hanger.  I heard a couple months ago about the fit problem but

 decided to wait until I was to the point of needing it before calling

 Sam.  He called me about two weeks ago to let me know about the problem

 and that a new one was being shipped that day.  Luckily he called before

 going to UPS or my plenum would be sitting at an abandoned workshop in

 TX rather than with me in WI!



   Once upon a time Deems and I were about even and doing a lot of the

 same things like engine, cowl, plenum, etc and I was the one doing a ton

 of due diligence and explaining it to the list.  Gotta say I'm glad this

 move is giving me a substantial break so Deems can have the steep

 learning curve for a while!  Although if I would have known about my

 little hiatus I could have willed him all of my slots as I have had the

 engine and plenum since OSH and the cowl for almost two months.  

 Can't wait for Deems to be flying as it's going to be like a preview of

 mine.



 Michael Sausen

 -10 #352 limbo



 --

_________________
Larry Rosen
#40356
N205EN (reserved)
<http>

Rick S.

Joined: 12 Feb 2006
Posts: 347
Location: Las Vegas

Posted: Tue Jan 16, 2007 10:28 pm Post subject: James Cowl & plenum

I agree!!! Lead on DEEMS!!!!



Actually I think Deems is the reincarnated James McClow...iF ewe knew whut I meen!!!  



Seriously though your site is a great help....



Rick S.

40185



do not archive

_________________
Rick S.
RV-10
40185

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