---------------------------------------------------------- JabiruEngine-List Digest Archive --- Total Messages Posted Tue 09/08/09: 25 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 02:52 AM - Re: Re: Here's an idea that DIDN'T work (Lynn Matteson) 2. 03:32 AM - Re: Here's an idea that DIDN'T work (Lynn Matteson) 3. 05:22 AM - Re: Here's an idea that DIDN'T work (Lynn Matteson) 4. 05:41 AM - Re: Here's an idea that DIDN'T work (Lynn Matteson) 5. 06:28 AM - Re: Here's an idea that DIDN'T work (zeprep251@aol.com) 6. 06:41 AM - Rotec carb at WOT (Mark Hubelbank) 7. 06:53 AM - Re: Here's an idea that DIDN'T work (Lynn Matteson) 8. 07:25 AM - Re: Here's an idea that DIDN'T work (Richard Girard) 9. 07:25 AM - Re: Rotec carb at WOT (Lynn Matteson) 10. 07:25 AM - Bing Carb (David Brown) 11. 07:53 AM - Re: Here's an idea that DIDN'T work (Lynn Matteson) 12. 08:55 AM - Re: Here's an idea that DIDN'T work (Dave) 13. 08:55 AM - Re: Bing Carb (Lynn Matteson) 14. 10:13 AM - Re: Here's an idea that DIDN'T work (Lynn Matteson) 15. 11:08 AM - Re: Here's an idea that DIDN'T work (=?iso-8859-1?Q?J=E9rme_Delamare?=) 16. 11:55 AM - Re: Here's an idea that DIDN'T work (Richard Girard) 17. 02:22 PM - Re: Here's an idea that DIDN'T work (Dave) 18. 03:13 PM - Re: Here's an idea that DIDN'T work (Peter Harris) 19. 03:13 PM - Re: Here's an idea that DIDN'T work (Peter Harris) 20. 03:42 PM - Re: Here's an idea that DIDN'T work (Lynn Matteson) 21. 04:14 PM - Re: Here's an idea that DIDN'T work (Lynn Matteson) 22. 04:45 PM - Re: Re: Here's an idea that DIDN'T work (Lynn Matteson) 23. 06:17 PM - Re: Here's an idea that DIDN'T work (Peter Harris) 24. 08:28 PM - Re: Here's an idea that DIDN'T work (Lynn Matteson) 25. 09:24 PM - Re: Here's an idea that DIDN'T work (Peter Harris) ________________________________ Message 1 _____________________________________ Time: 02:52:57 AM PST US From: Lynn Matteson Subject: Re: JabiruEngine-List: Re: 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: > > 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 > > ________________________________ Message 2 _____________________________________ Time: 03:32:34 AM PST US From: Lynn Matteson Subject: Re: JabiruEngine-List: 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: > > > 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 > > ________________________________ Message 3 _____________________________________ Time: 05:22:53 AM PST US From: Lynn Matteson Subject: Re: JabiruEngine-List: 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: > > > 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 > ________________________________ Message 4 _____________________________________ Time: 05:41:52 AM PST US From: Lynn Matteson Subject: Re: JabiruEngine-List: 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@aol.com wrote: > Thanks Lynn, > One good picture answered all the questions. > G.Aman > > ________________________________ Message 5 _____________________________________ Time: 06:28:33 AM PST US Subject: Re: JabiruEngine-List: Here's an idea that DIDN'T work From: zeprep251@aol.com 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 Sent: Tue, Sep 8, 2009 8:29 am Subject: Re: JabiruEngine-List: 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@aol.com wrote:? ? > Thanks Lynn,? > One good picture answered all the questions.? > G.Aman? >? >? >? ? ? ? ________________________________ Message 6 _____________________________________ Time: 06:41:24 AM PST US From: Mark Hubelbank Subject: JabiruEngine-List: Rotec carb at WOT Lynn I just ordered a Rotec for my Jabiru 3300. I hope I have done the right thing. Concerning your experience with WOT producing slightly reduced power, was the EGT going down when this happened meaning the mixture was getting so rich that it was past acceptable levels? If this was true, then leaning slightly to get the EGT back up to Jabiru's recommended 1250F (assuming your engine has the same recommendations) should have helped. -- Mark Hubelbank NorthEast Monitoring 2 Clock Tower Place Suite 555 Maynard, MA, 01754 - USA mhubel@nemon.com 978-443-3955 ________________________________ Message 7 _____________________________________ Time: 06:53:12 AM PST US From: Lynn Matteson Subject: Re: JabiruEngine-List: 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@aol.com wrote: > 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 > To: jabiruengine-list@matronics.com > Sent: Tue, Sep 8, 2009 8:29 am > Subject: Re: JabiruEngine-List: 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@aol.com wrote: > > > Thanks Lynn, > > One good picture answered all the questions. > > G.Aman > > > > > > > > > www.matronics.com/contribution _- > =========================================================== ________________________________ Message 8 _____________________________________ Time: 07:25:13 AM PST US Subject: Re: JabiruEngine-List: Here's an idea that DIDN'T work From: Richard Girard 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 wrote: > > 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: > >> peterjfharris@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 >> >> > > ________________________________ Message 9 _____________________________________ Time: 07:25:13 AM PST US From: Lynn Matteson Subject: Re: JabiruEngine-List: Rotec carb at WOT I really can't say that the power was reduced at WOT (although it probably was), it's just that following Paul's recommendations, I dialed the throttle back and saw the fuel flow increase and the rpm's increase as well. It felt like the engine was puling the same power but that's hard to tell. And concerning the EGT's, I can't say as I noticed the EGT's during that same takeoff as when I'm watching the tach and the fuel flow. When I take off, I use full rich mixture, as it's kind of "puckerey" to be messing with the mixture during the takeoff...for me anyway. Now when I land, that's where I DON'T go full rich like most POH's say...I keep my hand near the mixture, on the throttle, ready for a possible go-around, but the engine runs a lot better during landings at full lean. Heck, I pull full lean at about the start of the turn to base and leave it there. If I have to go around, I hit full rich, and ease the throttle in full. I've tried to go to full throttle from a lean setting while at altitude, and the engine bogs to almost quitting. To save it, I hit full rich, pull back to closed throttle, and ease the throttle in, taking about 1-2 seconds to go from closed throttle to WOT. With your 3300, you may not have to resort to a slightly less than WOT to get best rev count. Because the Rotec TBI was designed for a 2800 or 3600 cc engine, it is larger than my 2200 "should" take. But it might work just fine on yours without the restricted throttle operation. When I first tried the "short throttle" I was going to stack a few slotted washers on the throttle control, but found it easier to just push it WOT, then dial (vernier) it back until I felt a 1/4" or so gap. Because of my throttle control moving almost 3", and the slide on the TBI moving about 1-3/4" (?), I'd guess that I'm only restricting about 1/16" to 1/8" of full slide opening. Next time I go up (raining like a bear p------ on a flat rock, today) I'll see what WOT versus 1/4" less-than-WOT produces in terms of rpm, fuel flow, EGT, CHT, etc., at altitude, and I'll also see what the EGT's are like. I already know what the rpm's and fuel flow are doing during takeoff, so I can pretty much forget watching them and concentrate on the EGT's wile I dial the throttle back...good thought, Mark. In talking with a guy with a Europa, he ordered one but there wasn't room to install it...hope you've got the room, Mark. It really is less room-consuming front-to-back, but a bit more room is required in the throttle slide direction. 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 9:30 AM, Mark Hubelbank wrote: > > > Lynn > I just ordered a Rotec for my Jabiru 3300. I hope I have done the > right thing. Concerning your experience with WOT producing slightly > reduced power, was the EGT going down when this happened meaning > the mixture was getting so rich that it was past acceptable levels? > If this was true, then leaning slightly to get the EGT back up to > Jabiru's recommended 1250F (assuming your engine has the same > recommendations) should have helped. > > -- > Mark Hubelbank > NorthEast Monitoring > 2 Clock Tower Place > Suite 555 > Maynard, MA, 01754 - USA > mhubel@nemon.com > 978-443-3955 > > ________________________________ Message 10 ____________________________________ Time: 07:25:14 AM PST US Subject: JabiruEngine-List: Bing Carb From: "David Brown" I bent up a set of X vanes made of Stainless steel thin sheet about 2" long, not made to rotate the air, but to straighten it just before the carbi. Inserted it in the scat tubing. Bent flanges so that it keeps tension on the sides of the tubing so that it cannot move. Max EGTs range from 1330 to 1370 now. No reduction of power, maybe a little increase. I wouldn't trade my bing now. I get about 4.7GPH at 2750 RPM, 115 MPH. David 601XL JAB 3300 N601EX 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 Time: 10:10:16 PM PST US Subject: Re: JabiruEngine-List: Here's an idea that DIDN'T work From: Richard Girard 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 wrote: > 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 > > ________________________________ Message 11 ____________________________________ Time: 07:53:40 AM PST US From: Lynn Matteson Subject: Re: JabiruEngine-List: 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: > 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 > ________________________________ Message 12 ____________________________________ Time: 08:55:20 AM PST US From: "Dave" Subject: Re: JabiruEngine-List: 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 :-) ($!). ----- Original Message ----- From: "Lynn Matteson" Sent: Tuesday, September 08, 2009 11:32 AM Subject: Re: JabiruEngine-List: 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: > >> 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 >> > > > ________________________________ Message 13 ____________________________________ Time: 08:55:23 AM PST US From: Lynn Matteson Subject: Re: JabiruEngine-List: Bing Carb Good idea, David....now if you had a way to lean the Bing (maybe a HACman?), you'd really love it. : ) I'm not sure that the HACman works at all altitudes, though....I just don't know much about it. I did a similar thing with a fiberglass tube with X vanes, built right into my Bing air intake, and found that rotating the air intake would affect EGT's and which banks were hotter, left to right. It would be nice to have a cabin-controlled set of X vanes so that instant observation of results could be obtained. 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 10:24 AM, David Brown wrote: > > > I bent up a set of X vanes made of Stainless steel thin sheet about 2" > long, not made to rotate the air, but to straighten it just before the > carbi. Inserted it in the scat tubing. Bent flanges so that it keeps > tension on the sides of the tubing so that it cannot move. Max EGTs > range from 1330 to 1370 now. No reduction of power, maybe a little > increase. I wouldn't trade my bing now. I get about 4.7GPH at 2750 > RPM, > 115 MPH. > > David 601XL JAB 3300 > N601EX ________________________________ Message 14 ____________________________________ Time: 10:13:36 AM PST US From: Lynn Matteson Subject: Re: JabiruEngine-List: 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: > > > 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 :-) ($!). > > ----- Original Message ----- From: "Lynn Matteson" > To: > Sent: Tuesday, September 08, 2009 11:32 AM > Subject: Re: JabiruEngine-List: 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 ________________________________ Message 15 ____________________________________ Time: 11:08:17 AM PST US From: =?iso-8859-1?Q?J=E9rme_Delamare?= Subject: RE: JabiruEngine-List: 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 ? Jrme, dreaming -----Original Message----- From: owner-jabiruengine-list-server@matronics.com [mailto:owner-jabiruengine-list-server@matronics.com] On Behalf Of Lynn Matteson Sent: mardi 8 septembre 2009 18:58 Subject: Re: JabiruEngine-List: 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: > > > 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 :-) ($!). > > ----- Original Message ----- From: "Lynn Matteson" > To: > Sent: Tuesday, September 08, 2009 11:32 AM > Subject: Re: JabiruEngine-List: 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 ________________________________ Message 16 ____________________________________ Time: 11:55:14 AM PST US Subject: Re: JabiruEngine-List: Here's an idea that DIDN'T work From: Richard Girard http://www.megamanual.com/index.html The megasquirt project has been aroun d for awhile. That might be a simple adaptation. Rick Girard On Tue, Sep 8, 2009 at 12:58 PM, J=E9rme Delamare wrote: > =?iso-8859-1?Q?J=E9rme_Delamare?= > > Hi Lynn, > > Electronic could be the cheap way ;o) > > For example, the electric homemade system I described few weeks ago to le an > 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 ? > > J=E9rme, dreaming > > > -----Original Message----- > From: owner-jabiruengine-list-server@matronics.com > [mailto:owner-jabiruengine-list-server@matronics.com] On Behalf Of Lynn > Matteson > Sent: mardi 8 septembre 2009 18:58 > To: jabiruengine-list@matronics.com > Subject: Re: JabiruEngine-List: 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: > > > > > > > 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 :-) ($!). > > > > ----- Original Message ----- From: "Lynn Matteson" > > To: > > Sent: Tuesday, September 08, 2009 11:32 AM > > Subject: Re: JabiruEngine-List: 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 > > =========== =========== =========== =========== > > ________________________________ Message 17 ____________________________________ Time: 02:22:58 PM PST US From: "Dave" Subject: Re: JabiruEngine-List: 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. ----- Original Message ----- From: "Lynn Matteson" Sent: Tuesday, September 08, 2009 1:57 PM Subject: Re: JabiruEngine-List: 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 ________________________________ Message 18 ____________________________________ Time: 03:13:19 PM PST US From: "Peter Harris" Subject: RE: JabiruEngine-List: 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@matronics.com [mailto:owner-jabiruengine-list-server@matronics.com] On Behalf Of zeprep251@aol.com Sent: Tuesday, 8 September 2009 11:18 PM 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 Sent: Tue, Sep 8, 2009 8:29 am Subject: Re: JabiruEngine-List: 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@aol.com wrote: > Thanks Lynn, > One good picture answered all the questions. > G.Aman > > > Checked by AVG - www.avg.com 18:03:00 ________________________________ Message 19 ____________________________________ Time: 03:13:19 PM PST US From: "Peter Harris" Subject: RE: JabiruEngine-List: 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 -----Original Message----- From: owner-jabiruengine-list-server@matronics.com [mailto:owner-jabiruengine-list-server@matronics.com] On Behalf Of Lynn Matteson Sent: Tuesday, 8 September 2009 10:19 PM Subject: Re: JabiruEngine-List: 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: > > > 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 > Checked by AVG - www.avg.com 18:03:00 ________________________________ Message 20 ____________________________________ Time: 03:42:12 PM PST US From: Lynn Matteson Subject: Re: JabiruEngine-List: 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, Jrme Delamare wrote: > J=E9rme_Delamare?= > > 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 ? > > Jrme, dreaming > ________________________________ Message 21 ____________________________________ Time: 04:14:32 PM PST US From: Lynn Matteson Subject: Re: JabiruEngine-List: 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: > > > 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 ________________________________ Message 22 ____________________________________ Time: 04:45:08 PM PST US From: Lynn Matteson Subject: Re: JabiruEngine-List: Re: 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: > > > 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 >> >> >> > > ________________________________ Message 23 ____________________________________ Time: 06:17:51 PM PST US From: "Peter Harris" Subject: RE: JabiruEngine-List: 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 -----Original Message----- From: owner-jabiruengine-list-server@matronics.com [mailto:owner-jabiruengine-list-server@matronics.com] On Behalf Of Lynn Matteson Sent: Wednesday, 9 September 2009 9:10 AM Subject: Re: JabiruEngine-List: 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: > > > 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 Checked by AVG - www.avg.com 06:48:00 ________________________________ Message 24 ____________________________________ Time: 08:28:35 PM PST US From: Lynn Matteson Subject: Re: JabiruEngine-List: Here's an idea that DIDN'T work Have you had a look at the Rotec TBI? It is similar to the A'carb, but in my opinion, it is better built, and looks like it has better atomization. It almost HAS to have better fuel atomization, being that the fuel is being introduced to the air through 50-some tiny holes in the metering tube. I've had an Aerocarb in my hands, and although I've not used it, I just like the way the Rotec is built, and the way the slide feels when operated. And given the fact that the Rotec I bought and installed has worked right from the first flight, and reading the stories...yours included....of those who have tried the A'carb and hated it, I'd have to say that the Rotec is a better/easier unit to use. Where would I find info on the "NACA principle"? I may at some future point have to remove my muffler as well, but I'd rather keep my engine quieter, rather than go for more horsepower. I don't want to overstress the engine, just make it more efficient in operation, so I'm not looking at producing more horsepower or rpm's, just reliability and smooth operation. 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 9:01 PM, Peter Harris wrote: > > > 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 > > -----Original Message----- > From: owner-jabiruengine-list-server@matronics.com > [mailto:owner-jabiruengine-list-server@matronics.com] On Behalf Of > Lynn > Matteson > Sent: Wednesday, 9 September 2009 9:10 AM > To: jabiruengine-list@matronics.com > Subject: Re: JabiruEngine-List: Here's an idea that DIDN'T work > > > > Which Pete? Peter Disher? Pete Krotje? ________________________________ Message 25 ____________________________________ Time: 09:24:02 PM PST US From: "Peter Harris" Subject: RE: JabiruEngine-List: Here's an idea that DIDN'T work Lynn, I have attached a pic of the modified tail pipes. You will be familiar with the shape. There is a progressive reduction in pressure as the exhaust progresses out the pipe. This eliminates the "bark" and should make for reduced back pressure. It was one of those ideas you get in the middle of the night. (Normally this NACA shape is used as an air inlet) I found it softened the tone and is comfortable noise level in flight. I will look into the Rotec but at present I am running fuel injection with a Jenvey throttle body. The Aerocarb suffers from basic design faults because of the offset leverage from the cable attachment. At low throttle settings it can jam and the harder you pull the cable the harder it jams. Peter -----Original Message----- From: owner-jabiruengine-list-server@matronics.com [mailto:owner-jabiruengine-list-server@matronics.com] On Behalf Of Lynn Matteson Sent: Wednesday, 9 September 2009 1:28 PM Subject: Re: JabiruEngine-List: Here's an idea that DIDN'T work Have you had a look at the Rotec TBI? It is similar to the A'carb, but in my opinion, it is better built, and looks like it has better atomization. It almost HAS to have better fuel atomization, being that the fuel is being introduced to the air through 50-some tiny holes in the metering tube. I've had an Aerocarb in my hands, and although I've not used it, I just like the way the Rotec is built, and the way the slide feels when operated. And given the fact that the Rotec I bought and installed has worked right from the first flight, and reading the stories...yours included....of those who have tried the A'carb and hated it, I'd have to say that the Rotec is a better/easier unit to use. Where would I find info on the "NACA principle"? I may at some future point have to remove my muffler as well, but I'd rather keep my engine quieter, rather than go for more horsepower. I don't want to overstress the engine, just make it more efficient in operation, so I'm not looking at producing more horsepower or rpm's, just reliability and smooth operation. 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 9:01 PM, Peter Harris wrote: > > > 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 > > -----Original Message----- > From: owner-jabiruengine-list-server@matronics.com > [mailto:owner-jabiruengine-list-server@matronics.com] On Behalf Of > Lynn > Matteson > Sent: Wednesday, 9 September 2009 9:10 AM > To: jabiruengine-list@matronics.com > Subject: Re: JabiruEngine-List: Here's an idea that DIDN'T work > > > > Which Pete? Peter Disher? Pete Krotje? 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