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zeprep251(at)aol.com
Guest

Posted: Mon Sep 07, 2009 4:55 pm Post subject: Here's an idea that DIDN'T work

Thanks Lynn,

   One good picture answered all the questions.

   G.Aman

 

   

 

   

 

 --

Lynn Matteson

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

Posted: Tue Sep 08, 2009 1:52 am Post subject: Here's an idea that DIDN'T work

Hi Jim-

Now that's an interesting idea! I'll give that a try the next time I  

have the bottom cowl off. I've been wanting to design a larger heat  

muff around the muffler, so that might be a good time to do some more  

intake manifold exploration.



Taking this thought a bit further, I might try something that would  

not be "trapped" between the two halves of the manifold, but could be  

inserted into the manifold from the front...right behind the 4-bolt  

"adapter flange". That would certainly make the changing of any  

different type "splitter wings" a lot easier. Maybe drill and tap the  

upper half of the manifold....oops, that material is not thick  

enough. Probably have to drill and tap the oil pan at the appropriate  

spot, so that the attaching bolt could go right through both halves  

of the manifold and secure into the pan. I don't recall if the oil  

pan is thicker at the point where the other bolts holding the  

manifold in place are secured. Do you have a spare oil pan, Jim, that  

you could look at? It would probably have to be the early 2200. I'm  

thinking that Jabiru would probably have cast in some "bumps" in that  

area where the bolts penetrate.



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 2:55 PM, jim wrote:



 	  Quote: 	
		   



 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

_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

Lynn Matteson

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

Posted: Tue Sep 08, 2009 2:32 am Post subject: Here's an idea that DIDN'T work

Good idea with the water testing.

It is interesting to note that even rotating my vaned air supply tube  

to the Bing carb, would have some influence on the fuel/air  

distribution to the engine, when I still had the Bing on there. There  

is a lot to be learned just by moving things around on one of these  

engines, and that may say something about how poorly the manifolding  

is designed in the first place.



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 5:53 PM, Peter Harris wrote:



 	  Quote: 	
		   

 <peterjfharris(at)bigpond.com>



 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

_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

Lynn Matteson

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

Posted: Tue Sep 08, 2009 4:22 am Post subject: Here's an idea that DIDN'T work

One thing I've found with the TBI is that I have to pull back from  

WOT about 1/4" on an approximately 3" long throttle throw, to get the  

max rpm's on takeoff. At full throw of the vernier throttle control,  

I'll see (on one climbout) maybe 2940 rpm, and if I pull (rotate,  

actually) back on the throttle about 1/4", I'll see 2990, maybe 3010  

rpm. I've done this back and forth during the climbout and the result  

is usually always an increase in rpm when pulled back from WOT. When  

I talked with Paul from Rotec at Oshkosh, he said that the use of the  

Rotec TBI on a 2200 Jabiru might require the need to reduce the  

travel on the slide a small amount for best results. Interestingly,  

Aerocarb suggests this same thing in their instructions.



My static reading is about 2850-2870 with both the TBI and when I had  

the Bing installed. I have a Sensenich 62" x 46" glass-covered wood  

prop, which for my airframe gives a decent climbout, but relatively  

good speed (for a draggy airframe) in cruise....maybe 95-105 mph.  

Straight and level rpm is about 3000-3100 on an average day.  

Sometimes I'll see this rpm on climbs, too, so it must depend on the  

atmospheric conditions.



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 5:44 PM, Peter Harris wrote:



 	  Quote: 	
		   

 <peterjfharris(at)bigpond.com>



 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

_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

Lynn Matteson

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

Posted: Tue Sep 08, 2009 4:41 am Post subject: Here's an idea that DIDN'T work

Gary-

Did you see the response by Jim of Jabiru Pacific...he said that some  

folks tried a round shape in that area, and it improved the EGT  

spread because of the extra turbulence created...go figure!  It just  

goes to show that experimentation is the only way to figure these  

things out....the "slide rule" isn't always the answer. (who uses  

slide rules these days, anyway?) : )



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 8:54 PM, zeprep251(at)aol.com wrote:



 	  Quote: 	
		     Thanks Lynn,

   One good picture answered all the questions.

   G.Aman

_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

zeprep251(at)aol.com
Guest

Posted: Tue Sep 08, 2009 5:28 am Post subject: Here's an idea that DIDN'T work

Lynn,

   Yes,I caught that post.The list is a great source of info when tuning.I never would have thought of twisting the carb 20 degrees to even up the egts.We need a injection system like they have available after market for the 912's,based on an automotive port injected one.Gotta get the fuel past this quirky intake plenum.

   Thanks G.Aman  

   

 

 --

Lynn Matteson

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

Posted: Tue Sep 08, 2009 5:53 am Post subject: Here's an idea that DIDN'T work

Yeah, twisting/rotating the carb works because of the splitter  

sitting right in the middle of the air/fuel flow. Rotating the carb  

biases the flow to one side of the splitter or the other.



Some where on my list of things to do, is a direct port  

injector.....it's just that I can't find the list, so I don't know  

where that project is located. First comes painting my skis, as  

winter will soon be here. : )



Over on the yahoo Jabiru-engine group are a few pictures of an  

injection system that somebody in France built. Don't know anything  

more about it other than the pics. It was posted on Mar 20, 2008 and  

was developed by "Jab France"...don't know how it worked out.



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 8, 2009, at 9:18 AM, zeprep251(at)aol.com wrote:



[quote] Lynn,

   Yes,I caught that post.The list is a great source of info when  

 tuning.I never would have thought of twisting the carb 20 degrees  

 to even up the egts.We need a injection system like they have  

 available after market for the 912's,based on an automotive port  

 injected one.Gotta get the fuel past this quirky intake plenum.

   Thanks G.Aman



 --

_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

aslsa.rng(at)gmail.com
Guest

Posted: Tue Sep 08, 2009 6:25 am Post subject: Here's an idea that DIDN'T work

Lynn, Take off the air filter, pull the throttle to wide open and take a look in the throttle bore. I'm guessing you'll find the slide is far up above the bore. This is a problem with the Bing 54's used on two strokes, but the pressure actuated diaphagm of the 64 usually doesn't. 



Rick



On Tue, Sep 8, 2009 at 7:19 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)>

 

 One thing I've found with the TBI is that I have to pull back from WOT about 1/4" on an approximately 3" long throttle throw, to get the max rpm's on takeoff. At full throw of the vernier throttle control, I'll see (on one climbout) maybe 2940 rpm, and if I pull (rotate, actually) back on the throttle about 1/4", I'll see 2990, maybe 3010 rpm. I've done this back and forth during the climbout and the result is usually always an increase in rpm when pulled back from WOT. When I talked with Paul from Rotec at Oshkosh, he said that the use of the Rotec TBI on a 2200 Jabiru might require the need to reduce the travel on the slide a small amount for best results. Interestingly, Aerocarb suggests this same thing in their instructions.

  

 My static reading is about 2850-2870 with both the TBI and when I had the Bing installed. I have a Sensenich 62" x 46" glass-covered wood prop, which for my airframe gives a decent climbout, but relatively good speed (for a draggy airframe) in cruise....maybe 95-105 mph. Straight and level rpm is about 3000-3100 on an average day. Sometimes I'll see this rpm on climbs, too, so it must depend on the atmospheric conditions.

  

 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 5:44 PM, Peter Harris wrote:

 

  	  Quote: 	
		   --> JabiruEngine-List message posted by: "Peter Harris" <peterjfharris(at)bigpond.com (peterjfharris(at)bigpond.com)>

 

 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

 

 	
 

 

 ===========

 -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: Tue Sep 08, 2009 6:53 am Post subject: Here's an idea that DIDN'T work

The Rotec TBI is limited internally, so the throttle slide can only  

open to flush with the bore. Good thought though, 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

do not archive



On Sep 8, 2009, at 9:58 AM, Richard Girard wrote:



 	  Quote: 	
		   Lynn, Take off the air filter, pull the throttle to wide open and  

 take a look in the throttle bore. I'm guessing you'll find the  

 slide is far up above the bore. This is a problem with the Bing  

 54's used on two strokes, but the pressure actuated diaphagm of the  

 64 usually doesn't.



 Rick

_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

dave.go

Joined: 20 Jul 2009
Posts: 26

Posted: Tue Sep 08, 2009 7:55 am Post subject: Here's an idea that DIDN'T work

Hi Lynn, I've been sort of following your carb discusiion, Part of the issue 

you may see when reducing throttle setting results in increased fuel/power 

is related to velocity of the incoming air. Remember that the fuel is drawn 

as a result of reduced pressure in a venturi due to velocity. If you reduce 

the velocity of airflow, the fuel charge can actually become leaner. In fact 

in some bikes I've ridden including my ratty old BMW opening the throttle 

fully will result in an instant dead engine below a certain RPM.



Get working on the direct port injection. It's the only way you'll avoid 

compromises. Closed loop, with a feedback sensor on each pipe  ($!).



---

Lynn Matteson

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

Posted: Tue Sep 08, 2009 9:13 am Post subject: Here's an idea that DIDN'T work

Hi Dave-

I was thinking of going the cheap way....no electronics, no feedback  

sensors, just good ol' Hilborn injector-type thinking.....a pump, an  

orifice, and a metering block, with by-pass jet to control the amount  

of fuel at various rpm's. In fact, there was an old system of fuel  

injection built by Scott back in the 60's, that I got all excited  

reading about. The theory was that a particular size orifice will  

allow a certain amount of liquid to flow at a certain amount of  

pressure. To double this flow, you need 4 times the pressure. To  

triple the flow, you need 9 times the pressure. In other words, the  

pressure required to get a certain amount of liquid to flow through a  

given orifice is given as the square of the amount of increase  

desired. Need 5 times the amount through the same hole?....increase  

the pressure by 25 times.



(I hope I'm remembering all this correctly)



Now, a centrifugal pump will put out a certain amount of liquid while  

rotating at a certain rpm. If you want to double the output, increase  

the rpm by 4 times.....can you see where this is going? So, according  

to the article I read, Scott Injection used a centrifugal pump that  

was belt-driven off the engines' crankshaft, and if the rpm of the  

engine was increased by 2-fold, the fuel pressure went up 4-fold, and  

guess what?...the engine needed this much more fuel to run at that  

rpm, so everybody was happy. The fuel flowed through the same size  

orifice and no metering block (with bypass jets to dump the extra  

fuel) was needed, like the Hilborn injectors of that era.



I actually built an injector system for a old tired 392 Chrysler  

Hemi, using this theory, and a borrowed Scott injector pump. The  

injector that I built was a sliding-throttle injector, and I used  

brass fittings fitted with sewing machine needles for the needle/ 

orifice/spray bar part, and when I first started this thing up, it  

was amazing how good it ran. And when I got the throttle plates to  

open.....the plates were being sucked down hard due to the vacuum of  

the engine.....the damn thing was torquing itself almost right off  

the engine stand. Never got it to make a pass though the quarter mile  

though, due to a cracked magneto cap, and the guy whose car I  

borrowed to put the engine in, needed his car back. I think I was  

going through a divorce (probably spending too much time in the  

garage, and not enough in bed) at the time and never put the injector  

on another engine, and finally traded the injector off and it never  

ran again as far as I can recall. I know I had to give the Scott pump  

back to its owner, too.



I'm thinking of getting another Scott pump if anybody knows of one.  

They made two pumps...one was square-ish in shape, made for smaller  

engine requirements, and one was larger, and more rounded in shape,  

made for larger engines. Probably doing a search for Scott will find  

me one.



Well, that certainly was a nice trip down memory lane....can anybody  

guess that it's raining out, and I can't fly? : )



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 8, 2009, at 11:11 AM, Dave wrote:



[quote] 

 <d.goddard(at)ns.sympatico.ca>



 Hi Lynn, I've been sort of following your carb discusiion, Part of  

 the issue you may see when reducing throttle setting results in  

 increased fuel/power is related to velocity of the incoming air.  

 Remember that the fuel is drawn as a result of reduced pressure in  

 a venturi due to velocity. If you reduce the velocity of airflow,  

 the fuel charge can actually become leaner. In fact in some bikes  

 I've ridden including my ratty old BMW opening the throttle fully  

 will result in an instant dead engine below a certain RPM.



 Get working on the direct port injection. It's the only way you'll  

 avoid compromises. Closed loop, with a feedback sensor on each  

 pipe  ($!).



 ---

_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

jeromedelamare(at)free.fr
Guest

Posted: Tue Sep 08, 2009 10:08 am Post subject: Here's an idea that DIDN'T work

Hi Lynn,



Electronic could be the cheap way  ;o)



For example, the electric homemade system I described few weeks ago to lean

a bing cost... 0$

You just have to find a small electric motor (in an old printer for

example), spend a few hours to build a pump and you're ready to lean.

0$, 0 mechanical adaptation, no carb to trim and no fear during the first

take off ;o)



Perhaps of a small electrical system could reduce EGT spread to ?



Jérôme, dreaming 

  



--

aslsa.rng(at)gmail.com
Guest

Posted: Tue Sep 08, 2009 10:55 am Post subject: Here's an idea that DIDN'T work

http://www.megamanual.com/index.html



[url=http://www.megamanual.com/index.html][/url]The megasquirt project has been around for awhile. That might be a simple adaptation.

 



Rick Girard



On Tue, Sep 8, 2009 at 12:58 PM, Jérôme Delamare <jeromedelamare(at)free.fr (jeromedelamare(at)free.fr)> wrote:

 [quote]--> JabiruEngine-List message posted by: =?iso-8859-1?Q?J=E9r=F4me_Delamare?= <jeromedelamare(at)free.fr (jeromedelamare(at)free.fr)>

  

 Hi Lynn,

 

 Electronic could be the cheap way  ;o)

 

 For example, the electric homemade system I described few weeks ago to lean

 a bing cost... 0$

 You just have to find a small electric motor (in an old printer for

 example), spend a few hours to build a pump and you're ready to lean.

 0$, 0 mechanical adaptation, no carb to trim and no fear during the first

 take off ;o)

 

 Perhaps of a small electrical system could reduce EGT spread to ?

 

 Jérôme, dreaming

 

 

 --

dave.go

Joined: 20 Jul 2009
Posts: 26

Posted: Tue Sep 08, 2009 1:22 pm Post subject: Here's an idea that DIDN'T work

Can't speak about that system. I've never heard of most of it. I worked on a 

mechanical GM injection from an old '50s corvette but I can hardly remember 

it. You'll do a better job easier and faster with the new electronics, find 

a generic closed loop system  and the only thing you'll have to do is 

machine up an intake system and feed it the right fuel pressure. I remain of 

the "simpler is better " school though and I'd probably be happy with the 

bing and just tune for the hottest cylinder.



---

Peter H

Joined: 20 Mar 2007
Posts: 197

Posted: Tue Sep 08, 2009 2:13 pm Post subject: Here's an idea that DIDN'T work

Lynn,

My theory is that when WOT causes a reduction in power, or when the last

inch of throttle produces no effect ,I think that losses in the collector

are the cause.

Assuming collector losses, the WOT position would supply too much fuel and

run over rich especially to # 1 and 2.

For that reason I am concentrating on a symmetrical plenum fed from

underneath. 

I am impressed with what Pete has done.

Peter



--

Peter H

Joined: 20 Mar 2007
Posts: 197

Posted: Tue Sep 08, 2009 2:13 pm Post subject: Here's an idea that DIDN'T work

Gary,  

I think that these effects show that the collector dynamics are unstable, and a small change in any of the variables may make a big change in performance, but the effects vary  

over the power range.  

Peter        

From: owner-jabiruengine-list-server(at)matronics.com [mailto:owner-jabiruengine-list-server(at)matronics.com] On Behalf Of zeprep251(at)aol.com

 Sent: Tuesday, 8 September 2009 11:18 PM

 To: jabiruengine-list(at)matronics.com

 Subject: Re: JabiruEngine-List: Here's an idea that DIDN'T work  

Lynn,

   Yes,I caught that post.The list is a great source of info when tuning.I never would have thought of twisting the carb 20 degrees to even up the egts.We need a injection system like they have available after market for the 912's,based on an automotive port injected one.Gotta get the fuel past this quirky intake plenum.

   Thanks G.Aman    

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

 From: Lynn Matteson <lynnmatt(at)jps.net>

 To: jabiruengine-list(at)matronics.com

 Sent: Tue, Sep 8, 2009 8:29 am

 Subject: Re: Here's an idea that DIDN'T work    

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

 Gary- 

 Did you see the response by Jim of Jabiru Pacific...he said that some folks tried a round shape in that area, and it improved the EGT spread because of the extra turbulence created...go figure! It just goes to show that experimentation is the only way to figure these things out....the "slide rule" isn't always the answer. (who uses slide rules these days, anyway?) : ) 

 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 8:54 PM, zeprep251(at)aol.com (zeprep251(at)aol.com) wrote: 

 > Thanks Lynn, 

 > One good picture answered all the questions. 

 > G.Aman 

 > 

 > 

 > 

   	  Quote: 	

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		   http://www.matronics.com/Navigator?JabiruEngine-List 	
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9

No virus found in this incoming message.

 Checked by AVG - www.avg.com

 09/07/09 18:03:00

   [quote][b]

Lynn Matteson

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

Posted: Tue Sep 08, 2009 2:42 pm Post subject: Here's an idea that DIDN'T work

Hi Jerome-

Right now I have zero electrical gadgets on my plane that would  

prevent me from flying it...except the ignition. When I changed the  

stock ignition system for the Electroair, it was with the  

understanding that I could still someday find myself looking for  

another wheat field to land in....not that the stock ignition system  

was the cause for the first off-field landing. I have a redundant  

battery to hopefully delay that circumstance, ignition-wise, and a  

dual ignition system, of course. And I'm aware of the possibility of  

something else in the ignition system failing, just as I was aware of  

the rotors possibly falling off the stock system...which happened  

once. I'm just not that comfortable with electronics, and tend to  

stay away from using anything, let alone building anything,  

electronic in nature.

So I'm more apt to conger up some mechanical device to suit my fuel  

injection needs. And "apt to" doesn't mean I'd rule out trying an  

electronic fuel injection system, just that mechanical ones do work,  

albeit a little less convenient than the electronic ones.



Because I'm mechanical in nature, I find carb/injector leaning by  

hand interesting, and I would get bored flying if I didn't have  

something to think about, fiddle with, or  otherwise think about. The  

cost factor would not sway me either way when it came to using  

mechanical or electronic fuel injection. I'm not rich, I just like  

the challenge of building something mechanical....the "old way" if  

you will.



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 8, 2009, at 1:58 PM, Jérôme Delamare wrote:



 	  Quote: 	
		   

 J=E9r=F4me_Delamare?= <jeromedelamare(at)free.fr>



 Hi Lynn,



 Electronic could be the cheap way  ;o)



 For example, the electric homemade system I described few weeks ago  

 to lean

 a bing cost... 0$

 You just have to find a small electric motor (in an old printer for

 example), spend a few hours to build a pump and you're ready to lean.

 0$, 0 mechanical adaptation, no carb to trim and no fear during the  

 first

 take off ;o)



 Perhaps of a small electrical system could reduce EGT spread to ?



 Jérôme, dreaming

_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

Lynn Matteson

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

Posted: Tue Sep 08, 2009 3:14 pm Post subject: Here's an idea that DIDN'T work

Which Pete? Peter Disher? Pete Krotje?



Like you, I am convinced that the answer lies in the cylinders  

pulling their fuel/air charge from a central point, equidistant from  

the metering device. The next time I have the cowl off, I'm going to  

see how much room I have to play with down there. It might be as  

simple as rerouting the intake pipes...making new ones, most  

likely....and laying the TBI flat in an updraft configuration. Or  

making air-only controls for the pipes and mechanically injecting the  

fuel into the pipes, right at the valves.



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 8, 2009, at 6:05 PM, Peter Harris wrote:



 	  Quote: 	
		   

 <peterjfharris(at)bigpond.com>



 Lynn,

 My theory is that when WOT causes a reduction in power, or when the  

 last

 inch of throttle produces no effect ,I think that losses in the  

 collector

 are the cause.

 Assuming collector losses, the WOT position would supply too much  

 fuel and

 run over rich especially to # 1 and 2.

 For that reason I am concentrating on a symmetrical plenum fed from

 underneath.

 I am impressed with what Pete has done.

 Peter

_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

Lynn Matteson

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

Posted: Tue Sep 08, 2009 3:45 pm Post subject: Here's an idea that DIDN'T work

Listers-

I just revisited my picture collection, and found some pictures of  

the oil pan area where the manifold bolts on. I see that the area  

where a splitter wing through-bolt would penetrate through the  

manifold, is machined/cast away on the pan, so that a hole drilled  

completely through the manifold would exit out into open space. This  

would facilitate being able to slide modified splitter wings into the  

manifold, making experimenting with their shapes a LOT easier. All  

one would have to do is to remove a little metal from the area in  

front of the wing, on the upper and lower halves of the manifold, and  

future modified splitters could be easily installed/removed. I know  

that this is an area that I will be concentrating on in an effort to  

improve fuel/air distribution.

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 8, 2009, at 5:51 AM, Lynn Matteson wrote:

 	  Quote: 	

 <lynnmatt(at)jps.net>

 Hi Jim-

 Now that's an interesting idea! I'll give that a try the next time  

 I have the bottom cowl off. I've been wanting to design a larger  

 heat muff around the muffler, so that might be a good time to do  

 some more intake manifold exploration.

 Taking this thought a bit further, I might try something that would  

 not be "trapped" between the two halves of the manifold, but could  

 be inserted into the manifold from the front...right behind the 4- 

 bolt "adapter flange". That would certainly make the changing of  

 any different type "splitter wings" a lot easier. Maybe drill and  

 tap the upper half of the manifold....oops, that material is not  

 thick enough. Probably have to drill and tap the oil pan at the  

 appropriate spot, so that the attaching bolt could go right through  

 both halves of the manifold and secure into the pan. I don't recall  

 if the oil pan is thicker at the point where the other bolts  

 holding the manifold in place are secured. Do you have a spare oil  

 pan, Jim, that you could look at? It would probably have to be the  

 early 2200. I'm thinking that Jabiru would probably have cast in  

 some "bumps" in that area where the bolts penetrate.

 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 2:55 PM, jim wrote:

> 

>

> 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

>

_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

Peter H

Joined: 20 Mar 2007
Posts: 197

Posted: Tue Sep 08, 2009 5:17 pm Post subject: Here's an idea that DIDN'T work

Pete Disher.

Pete D has made a beautiful symmetrical updraft plenum close to what I have

in mind.

To make space for my (end fed) plenum I have removed the silencer.

I used the NACA principle to shape the pipe ends and this has softened the

exhaust note and theoretically reduced exhaust back pressure.

Without a balance pipe it beats a little but they say it sounds like a V8.

Re multipoint fuel injection it was beyond my budget as the injectors I am

using are $100 each and any alteration to the induction pipes I have found

is very time consuming.

In retrospect I am inclined to think that the use of a GOOD slide carb like

a Posa or the Revmaster and feeding a symmetrical plenum by updraft may give

as much power as fuel injection although the advantage of fuel injection is

better atomization. A slide good carb would be cheaper and maybe safer.It

may be significant to know that I made no gain in static RPM when I fuel

injected after removing the Bing.

At some future stage I may modify my Aerocarb and try it in place of my

throttle body but apart from the faulty cable actuation ,the mixture control

and atomization seems primitive.

I had a Posa fitted to a Revmaster some years ago and it worked perfectly

but I don't think they are available now.

Some time it would be good to try to quantify all these ideas by looking at

max. static RPM for a given prop.



Peter



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