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Lynn Matteson

Joined: 10 Jan 2006
Posts: 2778
Location: Grass Lake, Michigan

Posted: Sun Sep 06, 2009 7:24 pm Post subject: Here's an idea that DIDN'T work

Last week or so, I mentioned I was going to build a "turbulator" for  

my induction system. Here are pictures of what I built and what it  

looks (looked) like installed.



I cut and bent it out of stainless steel. The little "stems" sticking  

out of the tops of the vanes are what is used to hold it in place. I  

bent the vanes to about a 45 degree angle. After installation, I ran  

the engine up, and it seemed like the rpm's were fine, but on  

climbout it was about 200 rpm down, and pretty weak in climb. I  

thought it might have been the quite strong wind I was fighting, but  

the next day wasn't any better so I removed the device and power was  

restored. In retrospect, I think if I had made the outside a complete  

circle, and let the center of the vanes be more open...in other  

words, just have the vanes at the periphery, I think it might have  

worked. But I do not have the means to saw to the inside of a circle  

on my bandsaw...no blade welding attachment. I may try this  

experiment again if I can find a way to make it here at home.



By the way, this device is not intended to rotate. It is just  

supposed to make the air rotate, or become turbulent.



Lynn Matteson

Kitfox IV Speedster, taildragger

Jabiru 2200, #2062, 760.3 hrs

Sensenich 62"x46" Wood prop

Electroair direct-fire ignition system

Rotec TBI-40 injection

Status: flying

do not archive



On Sep 6, 2009, at 9:30 PM, mhubel wrote:



 	  Quote: 	
		   



 I am considering using the Rotac TBI 40 for a Jabiru 3300 in a  

 Zenith CH601XL.



 I wonder what your experience was with the primer button on the  

 regulator, did you connect it to a cable in the cabin? If so just  

 what sort of assembly was used?



 I was also wondering how the mixture cable was supported, I don't  

 see any method of supporting the mixture cable in the pictures on  

 the ROTAC web site.



 --------

 Mark Hubelbank





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p 61793#261793

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_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

pjdisher(at)bigpond.com
Guest

Posted: Sun Sep 06, 2009 8:15 pm Post subject: Here's an idea that DIDN'T work

Hi Lynn,

Late last year I tried the very same thing, a product made here, all ready 

aviable in Australia and distrubted to the car (auto) industry. Made of SS, 

6 vains and enclosed in a tube the diameter of the vains and a 1/2 long. 

cost me $165.00.

It did NOT work, just like your results NBG. I did get my money back.

Pete D

VH-PDI



---

Peter H

Joined: 20 Mar 2007
Posts: 197

Posted: Sun Sep 06, 2009 8:59 pm Post subject: Here's an idea that DIDN'T work

Lynn 

I tried a device like that and fitted about 6" upstream from the carb. but

did not see measurable improvement and it limited power so that the last

11/2" of throttle made no effect.

After 12 months of trials using a Jenvey throttle body and two injectors I

made a number of different plenums to replace the induction collector

supplied.

Because the Jab collector is fed from the end I found that fuel mix

distribution was not uniform throughout the power range and at times uneven

distribution R to L was causing the engine to vibrate. Also at WOT when the

butterfly is horizontal there is a significant reduction in turbulence and a

tendency for the heavier fuel droplets to accumulate at the far end,

enriching #1 and #2.

Using a bowl shaped plenum (as attached here) the effect was so bad that the

engine would shut down over the last inch of throttle with #1 and#2 miss

firing rich.

Based on static RPM I got no extra power from the plenum because the engine

failed rich every time.I spent hours trying to figure out why the breakdown.

I was able to correct this problem by fitting a 11/2" wide plate inside my

plenum placed about 1/2" directly in front of the inlet, like a big baffle.

Then the setup behaved exactly like the Jab collector. #1 and2 were rich at

WOT but the engine did not break down. I got the same max RPM, but noticed

that there was no increase in RPM for the last inch of throttle opening.

I have the same effect with my jab collector.

 	  Quote: 	
		  From all of this I deduce that 

1.	The collector as supplied suffers from internal losses which limit
	


max power at WOT. and prevent rich failure of #1 and#2

2.	There is the potential to make a plenum that would solve the problem

provided it has symmetrical outlets and is fed from the centre at the

bottom.

3.	There is the potential to get more uniform distribution of the

charge and with less induction losses there is the potential to get more

power.

That will be my next project but at present I have a lot of other

commitments.

Cheers

Peter



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aslsa.rng(at)gmail.com
Guest

Posted: Sun Sep 06, 2009 9:10 pm Post subject: Here's an idea that DIDN'T work

Lynn, Just a thought, but any airfoil surface, even a flat plate will stall at about a 12 to 16 degrees angle of attack.  Before you give up, try bending the vanes to something well below this, say 8 to 10 degrees.

 

Rick Girard



On Sun, Sep 6, 2009 at 10:21 PM, Lynn Matteson <lynnmatt(at)jps.net (lynnmatt(at)jps.net)> wrote:

[quote] Last week or so, I mentioned I was going to build a "turbulator" for my induction system. Here are pictures of what I built and what it looks (looked) like installed.

 

 



 I cut and bent it out of stainless steel. The little "stems" sticking out of the tops of the vanes are what is used to hold it in place. I bent the vanes to about a 45 degree angle. After installation, I ran the engine up, and it seemed like the rpm's were fine, but on climbout it was about 200 rpm down, and pretty weak in climb. I thought it might have been the quite strong wind I was fighting, but the next day wasn't any better so I removed the device and power was restored. In retrospect, I think if I had made the outside a complete circle, and let the center of the vanes be more open...in other words, just have the vanes at the periphery, I think it might have worked. But I do not have the means to saw to the inside of a circle on my bandsaw...no blade welding attachment. I may try this experiment again if I can find a way to make it here at home.

  

 By the way, this device is not intended to rotate. It is just supposed to make the air rotate, or become turbulent.

 

 Lynn Matteson

 Kitfox IV Speedster, taildragger

 Jabiru 2200, #2062, 760.3 hrs

 Sensenich 62"x46" Wood prop

 Electroair direct-fire ignition system

 Rotec TBI-40 injection

 Status: flying

 do not archive

 

 

 

 

 

 On Sep 6, 2009, at 9:30 PM, mhubel wrote:

 

  	  Quote: 	
		   --> Kitfox-List message posted by: "mhubel" <mhubel(at)nemon.com (mhubel(at)nemon.com)>

 

 I am considering using the Rotac TBI 40 for a Jabiru 3300 in a Zenith CH601XL.

 

 I wonder what your experience was with the primer button on the regulator, did you connect it to a cable in the cabin? If so just what sort of assembly was used?

 

 I was also wondering how the mixture cable was supported, I don't see any method of supporting the mixture cable in the pictures on the ROTAC web site.

 

 --------

 Mark Hubelbank

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=261793#261793

 

 

 

 

 

 

 

 

 

 

 	
 

 

[b]

wb2ssj(at)frontiernet.net
Guest

Posted: Mon Sep 07, 2009 2:23 am Post subject: Here's an idea that DIDN'T work

Lyn, your idea is like what was tried many years ago. JC Whitney used to 

sell them for cars and motor cycles. They had them installed at the air 

cleaner and spun the air prior to the carb. Also you have them too large a 

surface area. Cut them down a little and I think you will get better result. 

Tex

Lynn Matteson

Joined: 10 Jan 2006
Posts: 2778
Location: Grass Lake, Michigan

Posted: Mon Sep 07, 2009 2:56 am Post subject: Here's an idea that DIDN'T work

Hi Peter-

I've been wondering how you've been making out with your injection  

experiments. I too have been thinking about making the fuel  

distribution unit more centrally located, and came up with the  

thought of mounting my TBI below the engine, so that the intake tubes  

would all be equal in length ( your potential item #2) and not have  

to compete with each other for the incoming charge. Based on what  

I've learned while using this TBI and running "lean of peak EGT"  

tests, I made the pictured modifications to the intake manifold/ 

splitter, and it seems to have brought the front cylinders a bit  

closer to the rears in terms of EGT and CHT numbers.



Now when operating the engine lean of peak, the EGT's are within  

about 60 degrees F, and the CHT's are within a maximum of 20 degrees  

F., and as close as 1 degree of each other. I haven't tried to see  

how close the EGT's and CHT's would be at higher throttle openings,  

but I will.



  



Because of the title of this thread, I should state that these  

pictures are of an idea that DID work.



The first picture shows the area that I would remove from both  

halves, and the second picture shows that removal with just the lower  

half of the manifold/plenum done. After doing both halves, and test  

flying it, it seems to have helped the distribution of air to the  

front cylinders. At least it didn't hurt, and that's always nice when  

you're potentially ruining an expensive part. : )



Lynn Matteson

Kitfox IV Speedster, taildragger

Jabiru 2200, #2062, 760.3 hrs

Sensenich 62"x46" Wood prop

Electroair direct-fire ignition system

Rotec TBI-40 injection

Status: flying

do not archive



On Sep 7, 2009, at 12:55 AM, Peter Harris wrote:



 	  Quote: 	
		   Lynn

 I tried a device like that and fitted about 6" upstream from the  

 carb. but

 did not see measurable improvement and it limited power so that the  

 last

 11/2" of throttle made no effect.

 After 12 months of trials using a Jenvey throttle body and two  

 injectors I

 made a number of different plenums to replace the induction collector

 supplied.

 Because the Jab collector is fed from the end I found that fuel mix

 distribution was not uniform throughout the power range and at  

 times uneven

 distribution R to L was causing the engine to vibrate. Also at WOT  

 when the

 butterfly is horizontal there is a significant reduction in  

 turbulence and a

 tendency for the heavier fuel droplets to accumulate at the far end,

 enriching #1 and #2.

 Using a bowl shaped plenum (as attached here) the effect was so bad  

 that the

 engine would shut down over the last inch of throttle with #1 and#2  

 miss

 firing rich.

 Based on static RPM I got no extra power from the plenum because  

 the engine

 failed rich every time.I spent hours trying to figure out why the  

 breakdown.

 I was able to correct this problem by fitting a 11/2" wide plate  

 inside my

 plenum placed about 1/2" directly in front of the inlet, like a big  

 baffle.

 Then the setup behaved exactly like the Jab collector. #1 and2 were  

 rich at

 WOT but the engine did not break down. I got the same max RPM, but  

 noticed

 that there was no increase in RPM for the last inch of throttle  

 opening.

 I have the same effect with my jab collector.

> From all of this I deduce that

 1.	The collector as supplied suffers from internal losses which limit

 max power at WOT. and prevent rich failure of #1 and#2

 2.	There is the potential to make a plenum that would solve the  

 problem

 provided it has symmetrical outlets and is fed from the centre at the

 bottom.

 3.	There is the potential to get more uniform distribution of the

 charge and with less induction losses there is the potential to get  

 more

 power.

 That will be my next project but at present I have a lot of other

 commitments.

 Cheers

 Peter

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_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

Lynn Matteson

Joined: 10 Jan 2006
Posts: 2778
Location: Grass Lake, Michigan

Posted: Mon Sep 07, 2009 2:56 am Post subject: Here's an idea that DIDN'T work

Thanks for the tip, Rick. I'll keep that in mind if I decide to  

continue with this idea. I think if I tried to use the present piece  

and bent it more, the vanes would break off, but making a new one    

would let me try that idea. I try to use only the tools I have at  

home here, but it may be time to go to a local machine shop for help  

on this one. I originally was going to make it out of aluminum, but  

it was going to be a major amount of milling, so I tried the  

stainless steel and the band saw.



Lynn Matteson

Kitfox IV Speedster, taildragger

Jabiru 2200, #2062, 760.3 hrs

Sensenich 62"x46" Wood prop

Electroair direct-fire ignition system

Rotec TBI-40 injection

Status: flying

On Sep 7, 2009, at 1:02 AM, Richard Girard wrote:



 	  Quote: 	
		   Lynn, Just a thought, but any airfoil surface, even a flat plate  

 will stall at about a 12 to 16 degrees angle of attack.  Before you  

 give up, try bending the vanes to something well below this, say 8  

 to 10 degrees.



 Rick Girard

_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

aslsa.rng(at)gmail.com
Guest

Posted: Mon Sep 07, 2009 3:06 am Post subject: Here's an idea that DIDN'T work

Lynn, As it happens I have a small machine shop. If I can help out let me know. Rather than using stainless, you might consider using brass sheet and silver soldering the vanes on a hub.



Rick



 On Mon, Sep 7, 2009 at 5:55 AM, Lynn Matteson <lynnmatt(at)jps.net (lynnmatt(at)jps.net)> wrote:

[quote] --> JabiruEngine-List message posted by: Lynn Matteson <lynnmatt(at)jps.net (lynnmatt(at)jps.net)>

 

 Thanks for the tip, Rick. I'll keep that in mind if I decide to continue with this idea. I think if I tried to use the present piece and bent it more, the vanes would break off, but making a new one   would let me try that idea. I try to use only the tools I have at home here, but it may be time to go to a local machine shop for help on this one. I originally was going to make it out of aluminum, but it was going to be a major amount of milling, so I tried the stainless steel and the band saw. 

 

 Lynn Matteson

 Kitfox IV Speedster, taildragger

 Jabiru 2200, #2062, 760.3 hrs

 Sensenich 62"x46" Wood prop

 Electroair direct-fire ignition system

 Rotec TBI-40 injection

 Status: flying

 

 



 On Sep 7, 2009, at 1:02 AM, Richard Girard wrote:

 

  	  Quote: 	
		   Lynn, Just a thought, but any airfoil surface, even a flat plate will stall at about a 12 to 16 degrees angle of attack.  Before you give up, try bending the vanes to something well below this, say 8 to 10 degrees.

 

 Rick Girard

 

 	
 

 ===========

 -List" target="_blank">http://www.matronics.com/Navigator?JabiruEngine-List

 ===========

 http://forums.matronics.com

 ===========

 le, List Admin.

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

 ===========

 

 

 

 



[b]

Lynn Matteson

Joined: 10 Jan 2006
Posts: 2778
Location: Grass Lake, Michigan

Posted: Mon Sep 07, 2009 3:08 am Post subject: Here's an idea that DIDN'T work

Hi Peter-

What I was trying to copy WAS a product made for the car industry...a  

"cyclone-something". Did you try this in your Jabiru engine? When I  

searched the websites, I couldn't find one small enough to fit behind  

the injector body.



Lynn Matteson

Kitfox IV Speedster, taildragger

Jabiru 2200, #2062, 760.3 hrs

Sensenich 62"x46" Wood prop

Electroair direct-fire ignition system

Rotec TBI-40 injection

Status: flying



On Sep 7, 2009, at 12:07 AM, peter disher wrote:



[quote] 

 <pjdisher(at)bigpond.com>



 Hi Lynn,

 Late last year I tried the very same thing, a product made here,  

 all ready aviable in Australia and distrubted to the car (auto)  

 industry. Made of SS, 6 vains and enclosed in a tube the diameter  

 of the vains and a 1/2 long. cost me $165.00.

 It did NOT work, just like your results NBG. I did get my money back.

 Pete D

 VH-PDI



 ---

_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

Lynn Matteson

Joined: 10 Jan 2006
Posts: 2778
Location: Grass Lake, Michigan

Posted: Mon Sep 07, 2009 4:40 am Post subject: Here's an idea that DIDN'T work

Thanks for the input. Tex....after I got to looking at it, I realized  

that the vanes were too large, but thought that the edge thickness  

was not too much of a restriction, but the air moving through it had  

different ideas. : )  And yes, this was just a regurgitation of an  

old idea.



Lynn Matteson

Kitfox IV Speedster, taildragger

Jabiru 2200, #2062, 760.3 hrs

Sensenich 62"x46" Wood prop

Electroair direct-fire ignition system

Rotec TBI-40 injection

Status: flying

On Sep 7, 2009, at 6:22 AM, Tex Mantell wrote:



 	  Quote: 	
		   

 <wb2ssj(at)frontiernet.net>



 Lyn, your idea is like what was tried many years ago. JC Whitney  

 used to sell them for cars and motor cycles. They had them  

 installed at the air cleaner and spun the air prior to the carb.  

 Also you have them too large a surface area. Cut them down a little  

 and I think you will get better result. Tex

_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

Lynn Matteson

Joined: 10 Jan 2006
Posts: 2778
Location: Grass Lake, Michigan

Posted: Mon Sep 07, 2009 4:50 am Post subject: Here's an idea that DIDN'T work

Now THERE'S a good idea!  Sometimes I really overlook the obvious in  

my old age. You're absolutely right, a silver soldered assembly would  

be the way to go, and I can do this at home. I have a lathe, milling  

attachment, band saw, and all the assorted hand tools in my small  

shop, and sometimes I try to make a machined job, when all that is  

called for is the hand tools and the silver solder. Thanks for the  

suggestion and the offer to help, Rick.



Lynn Matteson

Kitfox IV Speedster, taildragger

Jabiru 2200, #2062, 760.3 hrs

Sensenich 62"x46" Wood prop

Electroair direct-fire ignition system

Rotec TBI-40 injection

Status: flying

On Sep 7, 2009, at 7:02 AM, Richard Girard wrote:



 	  Quote: 	
		   Lynn, As it happens I have a small machine shop. If I can help out  

 let me know. Rather than using stainless, you might consider using  

 brass sheet and silver soldering the vanes on a hub.



 Rick



 On Mon, Sep 7, 2009 at 5:55 AM, Lynn Matteson <lynnmatt(at)jps.net>  

 wrote:

 

 <lynnmatt(at)jps.net>



 Thanks for the tip, Rick. I'll keep that in mind if I decide to  

 continue with this idea. I think if I tried to use the present  

 piece and bent it more, the vanes would break off, but making a new  

 one   would let me try that idea. I try to use only the tools I  

 have at home here, but it may be time to go to a local machine shop  

 for help on this one. I originally was going to make it out of  

 aluminum, but it was going to be a major amount of milling, so I  

 tried the stainless steel and the band saw.

 Lynn Matteson

 Kitfox IV Speedster, taildragger

 Jabiru 2200, #2062, 760.3 hrs

 Sensenich 62"x46" Wood prop

 Electroair direct-fire ignition system

 Rotec TBI-40 injection

 Status: flying

 On Sep 7, 2009, at 1:02 AM, Richard Girard wrote:



 Lynn, Just a thought, but any airfoil surface, even a flat plate  

 will stall at about a 12 to 16 degrees angle of attack.  Before you  

 give up, try bending the vanes to something well below this, say 8  

 to 10 degrees.



 Rick Girard

 ===========

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

 JabiruEngine-List

 ===========

 http://forums.matronics.com

 ===========

 le, List Admin.

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

 ===========





 www.matronics.com/contribution _- 

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

_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

zeprep251(at)aol.com
Guest

Posted: Mon Sep 07, 2009 6:09 am Post subject: Here's an idea that DIDN'T work

Lynn,

  Is there any way to change the shape of the support bolt housing to tear drop?The round tube has to create a lot of turbulence down stream.

 

   Gary Aman Jabiru 2200A 475 hrs

 

   

 

 --

dons701

Joined: 22 May 2009
Posts: 80
Location: Hershey, PA

Posted: Mon Sep 07, 2009 7:48 am Post subject: Re: Here's an idea that DIDN'T work

Hi Lynn and All

  Just a few thoughts, a device that takes the "wet" flow of air and fuel and imparts a centrifuge effect will tend to throw the heavier droplets to the outside. I also remember a device that used four counter rotating vortices, created by bending metal tabs protruding inward from the inside of a large hole in sheet metal and claimed to solve the separation problem. I thought it was called Swarrup, or something like that, but when I tried to search the net I found nothing. 

  Thank you for the pictures of your manifold. Heavier droplets of fuel retain their kinetic energy and do not want to turn with the air only to slam to the front for 1&2.  One could wonder what would happen if the center divider was completely removed, what encouragement would the high velocity fuel and air have to alternately flow to the rear cylinders (3&4). 

   If the fuel and air were heated to the point of vaporization before entering the manifold you could have the even distribution needed to run leaner because the current system is rich to compromise the factory design.  Don

_________________
Zenith 701 #76120
Jabiru 2200A #2456 95 hours
Sensenich Wood 64-PJ-36 Prop

Lynn Matteson

Joined: 10 Jan 2006
Posts: 2778
Location: Grass Lake, Michigan

Posted: Mon Sep 07, 2009 8:10 am Post subject: Here's an idea that DIDN'T work

Do you mean the thing that sits between the upper and the lower  

halves of the manifold? I refer to this part as the splitter, and  

when I spoke with Pete about its shape, he said that Jabiru had done  

some testing and found the present shape to be the best. Here is a  

picture of that part and as you can see, it is already teardrop  

shaped when viewed from above. I had a notion to carve it into an  

hour-glass shape, (as seen viewed straight on, as in the picture I  

sent previously) and I still might, the next time I have the manifold  

off the engine. The only problem with that idea is that there is an  

(unused) threaded hole back at the narrow part of the teardrop, that  

would be exposed if I carved it to an hour glass shape. I thought of  

simply screwing an aluminum bolt into this hole, then proceeding with  

the shaping of it, but decided not to...guess I chickened out. That  

rear hole could also be filled with some structural adhesive/epoxy/ 

whatever, and then it would just be carved away as the shape took  

place. The front hole...the only one that gets used in the actual  

assembly...has enough meat around it, that it would allow some  

carving away on either side of it. Just to make sure we're on the  

same page here, this shot shows that splitter from above, and I would  

cut away on each side of the splitter such that the plan view of the  

splitter remains the same shape, but when viewed vertically, the  

sides are narrowed...like a good-lookin' babe in great shape when  

viewed from the front (minus a few of the "accessories" of course).



And of course when I say the "rear hole" it is actually toward the  

front of the engine in a tractor environment, but it is in the rear  

of the airflow.



Lynn Matteson

Kitfox IV Speedster, taildragger

Jabiru 2200, #2062, 760.3 hrs

Sensenich 62"x46" Wood prop

Electroair direct-fire ignition system

Rotec TBI-40 injection

Status: flying

On Sep 7, 2009, at 10:07 AM, zeprep251(at)aol.com wrote:



 	  Quote: 	
		   Lynn,

  Is there any way to change the shape of the support bolt housing  

 to tear drop?The round tube has to create a lot of turbulence down  

 stream.

 Gary Aman Jabiru 2200A 475 hrs

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_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

Lynn Matteson

Joined: 10 Jan 2006
Posts: 2778
Location: Grass Lake, Michigan

Posted: Mon Sep 07, 2009 8:42 am Post subject: Here's an idea that DIDN'T work

Thanks for your thoughts, Don. It might just be that the better  

atomization of the Rotec TBI is what is making my EGT's and CHT's  

more even than with the Bing. Smaller droplets, therefore less  

inertia. I seem to recall that Pete said that the factory tried  

several different shapes of that divider/splitter and could find  

nothing better than the present teardrop shape. He said they tried a  

more blunt shape as well. I can't believe they didn't try leaving it  

out, and they very well could have, but I don't recall whether Pete  

said that or not.



Speaking of "heated to the point of vaporization before entering the  

manifold", I have found that if I pull on the carb heat, my rpm's go  

up about 60-80, the fuel flow goes up about point-2 to point-3  

gallons per hour, and the plane turns slightly to the left, due to  

the increase in rpm/torque. This is during straight and level flight  

running about 2750 rpm's and using about 3.0 gph, during "lean of  

peak EGT" operation. When I push the carb heat off, the plane returns  

to the original flight direction, and the rpm's drop, as well as the  

fuel usage. Talk about sensitive! Now this turn to the left is not  

dramatic, just noticeable.



Lynn Matteson

Kitfox IV Speedster, taildragger

Jabiru 2200, #2062, 760.3 hrs

Sensenich 62"x46" Wood prop

Electroair direct-fire ignition system

Rotec TBI-40 injection

Status: flying

On Sep 7, 2009, at 11:48 AM, dons701 wrote:



 	  Quote: 	
		   

 <burdon1(at)comcast.net>



 Hi Lynn and All

   Just a few thoughts, a device that takes the "wet" flow of air  

 and fuel and imparts a centrifuge effect will tend to throw the  

 heavier droplets to the outside. I also remember a device that used  

 four counter rotating vortices, created by bending metal tabs  

 protruding inward from the inside of a large hole in sheet metal  

 and claimed to solve the separation problem. I thought it was  

 called Swarrup, or something like that, but when I tried to search  

 the net I found nothing.

   Thank you for the pictures of your manifold. Heavier droplets of  

 fuel retain their kinetic energy and do not want to turn with the  

 air only to slam to the front for 1&2.  One could wonder what would  

 happen if the center divider was completely removed, what  

 encouragement would the high velocity fuel and air have to  

 alternately flow to the rear cylinders (3&4).

    If the fuel and air were heated to the point of vaporization  

 before entering the manifold you could have the even distribution  

 needed to run leaner because the current system is rich to  

 compromise the factory design.  Don



 --------

 Zenith 701 #76120

 Jabiru #2456  51 hours





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p 61870#261870

_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

Jim McCormick

Joined: 19 Mar 2007
Posts: 18
Location: Fresno, CA

Posted: Mon Sep 07, 2009 10:57 am Post subject: Here's an idea that DIDN'T work

Hi Lynn



Something you may want to try is to replace the "splitter wing" with a round

bar stock 12mm in dia. I have had some customers try this with good results.

The theory behind the round stock it it cause's turbulence in the plenum for

better fuel distribution? But the guys that have done this report the EGT's

are more uniform between the cyl's..

Jim McCormick

Jabiru Pacific LLC

255 W Fallbrook Suite 202B

Fresno, Ca 93711

P 559.431.1701

F 559.233.3676

www.jabirupacific.com

On 9/7/09 9:35 AM, "Lynn Matteson" <lynnmatt(at)jps.net> wrote:



 	  Quote: 	
		   

 

 Thanks for your thoughts, Don. It might just be that the better

 atomization of the Rotec TBI is what is making my EGT's and CHT's

 more even than with the Bing. Smaller droplets, therefore less

 inertia. I seem to recall that Pete said that the factory tried

 several different shapes of that divider/splitter and could find

 nothing better than the present teardrop shape. He said they tried a

 more blunt shape as well. I can't believe they didn't try leaving it

 out, and they very well could have, but I don't recall whether Pete

 said that or not.

 

 Speaking of "heated to the point of vaporization before entering the

 manifold", I have found that if I pull on the carb heat, my rpm's go

 up about 60-80, the fuel flow goes up about point-2 to point-3

 gallons per hour, and the plane turns slightly to the left, due to

 the increase in rpm/torque. This is during straight and level flight

 running about 2750 rpm's and using about 3.0 gph, during "lean of

 peak EGT" operation. When I push the carb heat off, the plane returns

 to the original flight direction, and the rpm's drop, as well as the

 fuel usage. Talk about sensitive! Now this turn to the left is not

 dramatic, just noticeable.

 

 Lynn Matteson

 Kitfox IV Speedster, taildragger

 Jabiru 2200, #2062, 760.3 hrs

 Sensenich 62"x46" Wood prop

 Electroair direct-fire ignition system

 Rotec TBI-40 injection

 Status: flying

 

 

 

 

 

 

 On Sep 7, 2009, at 11:48 AM, dons701 wrote:

 

> 

> <burdon1(at)comcast.net>

> 

> Hi Lynn and All

>   Just a few thoughts, a device that takes the "wet" flow of air

> and fuel and imparts a centrifuge effect will tend to throw the

> heavier droplets to the outside. I also remember a device that used

> four counter rotating vortices, created by bending metal tabs

> protruding inward from the inside of a large hole in sheet metal

> and claimed to solve the separation problem. I thought it was

> called Swarrup, or something like that, but when I tried to search

> the net I found nothing.

>   Thank you for the pictures of your manifold. Heavier droplets of

> fuel retain their kinetic energy and do not want to turn with the

> air only to slam to the front for 1&2.  One could wonder what would

> happen if the center divider was completely removed, what

> encouragement would the high velocity fuel and air have to

> alternately flow to the rear cylinders (3&4).

>    If the fuel and air were heated to the point of vaporization

> before entering the manifold you could have the even distribution

> needed to run leaner because the current system is rich to

> compromise the factory design.  Don

> 

> --------

> Zenith 701 #76120

> Jabiru #2456  51 hours

> 

> 

> 

> 

> Read this topic online here:

> 

> http://forums.matronics.com/viewtopic.php?p 61870#261870

> 

> 

> 

> 

> 

> 

> 

> 

> 

>

Peter H

Joined: 20 Mar 2007
Posts: 197

Posted: Mon Sep 07, 2009 1:54 pm Post subject: Here's an idea that DIDN'T work

Looks like good work Lynn. Maybe you have got the splitter as good as it can

be.

I am interested in your test to WOT especially to see if you find no

increase in power for the last inch of throttle. I have taken this effect to

be an indication of losses in the collector (as proven by my test with the

baffle plate inserted) but it may be that my prop is overloading the system.

I am getting 2760RPM static with all of my ground tests.

The prop is 55X72 as used on my Quickie and I get 170KTS CAS at 2900RPM WOT

in level flight at 3000ft.It would be nice to find that extra power and

maybe set a record for this type.

Peter

 

--

Peter H

Joined: 20 Mar 2007
Posts: 197

Posted: Mon Sep 07, 2009 1:54 pm Post subject: Here's an idea that DIDN'T work

Hi Lynn,

Yes it was a product called "Hiclone" overpriced at AUD160 and very heavily

promoted as a boost to power and economy.It has a double row of vanes in SS.

The idea is probably OK but I think any benefit is offset by the choking

effect as the device limits airflow.

I think it would work better if the diameter was much larger, then perhaps

tapered to the TB entry. This would accelerate the swirling air with limited

obstruction to the flow.

BTW I found it useful to conduct some tests using a high pressure spray of

water from a spray gun.

Peter



--

Peter H

Joined: 20 Mar 2007
Posts: 197

Posted: Mon Sep 07, 2009 2:02 pm Post subject: Here's an idea that DIDN'T work

Don,

The induction collector is bolted flat to the sump.

When I discussed this with the Jabiru design engineer he admitted it was a

compromise. Heating the charge reduces efficiency but improves the

distribution as you suggest.

Peter



--

Peter H

Joined: 20 Mar 2007
Posts: 197

Posted: Mon Sep 07, 2009 2:03 pm Post subject: Here's an idea that DIDN'T work

Jim,

Afriend of mine has replaced this part with a half round shape with the flat

at rear and he claims an improvement in distribution.

But I intend to continue with experiments for a bottom fed symmetrical

plenum.

Peter



--

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