 |
Matronics Email Lists
Web Forum Interface to the Matronics Email Lists
|
| View previous topic :: View next topic |
| Author |
Message |
BobbyPaulk(at)comcast.net
Guest
|
 Posted: Fri Oct 22, 2010 6:05 am Post subject: Temps |
 |
|
List,
I am reading all kinds of info on what is supposed to be but where is the info on what is the proper jetting. I am particularly interested in a Jabiru 3300 ( with Hydraulic lifters ) on a Zodiac 601 XL. I am running a 260 Main Jet and 290 Needle Jet. It still appears I am running too lean. The EGT's go way up at 2500 ~ 2600 RPM and the 100 LL is burning very light gray. Is anyone running larger jetting. How about a different needle??
I also heard of some changes in the intake manifold although I can not confirm what has been done if anything.
Also would like to know what is an allowable Cylinder Head Temperature. I have them all below 300 except #6.
It goes up to 335 ~ 340 at some power settings. The lowest I can maintain is about 310.
I have tilted the carb, divided the intake elbow, changed the Ram Air Ducts, added baffles and I am still baffled : )
One day I would like to just get in the plane and enjoy the ride without having to be constantly watching what the temps are doing and I would like for my engine to last to TBO or at least near that.
Please comment on what your set up might be and the temps you are experiencing. What is acceptable on CHT for long term life of the engine??
Bobby
601 XL B
103 hrs. & still experimenting.
Jacksonville Fl.
[quote][b]
| | - The Matronics JabiruEngine-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?JabiruEngine-List |
|
|
|
| Back to top |
|
 |
mhubel
Joined: 05 Sep 2009
Posts: 141
|
| Posted: Fri Oct 22, 2010 7:35 am Post subject: Temps |
|
|
Bobby,
   Others may have this working but I never got a Bing to work in the CH601 airframe. The right angle bend of the airflow was just too much for it. I now have a TBI-40-3 (not S) mounted horizontally with a 2 inch spacer from the engine and so far it is an order of magnitude improvement. Of course, one can now set the mixture. I run it rich (EGT's around 1250 or below at high/full throttle) then lean it as soon as throttle is reduced. I have been posting pictures of this at photo.hubbles.com.
On 10/22/2010 10:02 AM, BobbyPaulk(at)comcast.net (BobbyPaulk(at)comcast.net) wrote: | Quote: | p { margin: 0; } List,
I am reading all kinds of info on what is supposed to be but where is the info on what is the proper jetting. I am particularly interested in a Jabiru 3300 ( with Hydraulic lifters ) on a Zodiac 601 XL. I am running a 260 Main Jet and 290 Needle Jet. It still appears I am running too lean. The EGT's go way up at 2500 ~ 2600 RPM and the 100 LL is burning very light gray. Is anyone running larger jetting. How about a different needle??
I also heard of some changes in the intake manifold although I can not confirm what has been done if anything.
Also would like to know what is an allowable Cylinder Head Temperature. I have them all below 300 except #6.
It goes up to 335 ~ 340 at some power settings. The lowest I can maintain is about 310.
I have tilted the carb, divided the intake elbow, changed the Ram Air Ducts, added baffles and I am still baffled  : )
One day I would like to just get in the plane and enjoy the ride without having to be constantly watching what the temps are doing and I would like for my engine to last to TBO or at least near that.
Please comment on what your set up might be and the temps you are experiencing. What is acceptable on CHT for long term life of the engine??
Bobby
601 XL B
103 hrs. & still experimenting.
Jacksonville Fl.
--
Mark Hubelbank
NorthEast Monitoring
2 Clock Tower Place
Suite 555
Maynard, MA, 01754 - USA
mhubel(at)nemon.com (mhubel(at)nemon.com)
978-443-3955 |
| | - The Matronics JabiruEngine-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?JabiruEngine-List |
|
_________________
Mark Hubelbank
N708HU
CH601XL
Jabiru 3300
Rotec TBI 40-3 carb
Sensenich ground adj prop.
240 hr TAF
Pictures at photo.hubbles.com |
|
| Back to top |
|
|
marvinlnaz(at)yahoo.com
Guest
|
| Posted: Fri Oct 22, 2010 9:25 am Post subject: Temps |
|
|
Mark, would you please elaborate on your leaning techniques? Specifically, at altitude and cruise power, what EGTs do you lean to?
Thanks,
marvin
N250MR
J250... 3300... w/ TBI40
From: Mark Hubelbank <mhubel(at)nemon.com>
To: jabiruengine-list(at)matronics.com
Sent: Fri, October 22, 2010 8:32:03 AM
Subject: Re: Temps
Bobby,
Others may have this working but I never got a Bing to work in the CH601 airframe. The right angle bend of the airflow was just too much for it. I now have a TBI-40-3 (not S) mounted horizontally with a 2 inch spacer from the engine and so far it is an order of magnitude improvement. Of course, one can now set the mixture. I run it rich (EGT's around 1250 or below at high/full throttle) then lean it as soon as throttle is reduced. I have been posting pictures of this at photo.hubbles.com.
On 10/22/2010 10:02 AM, BobbyPaulk(at)comcast.net (BobbyPaulk(at)comcast.net) wrote: [quote] p {margin:0;} List,
I am reading all kinds of info on what is supposed to be but where is the info on what is the proper jetting. I am particularly interested in a Jabiru 3300 ( with Hydraulic lifters ) on a Zodiac 601 XL. I am running a 260 Main Jet and 290 Needle Jet. It still appears I am running too lean. The EGT's go way up at 2500 ~ 2600 RPM and the 100 LL is burning very light gray. Is anyone running larger jetting. How about a different needle??
I also heard of some changes in the intake manifold although I can not confirm what has been done if anything.
Also would like to know what is an allowable Cylinder Head Temperature. I have them all below 300 except #6.
It goes up to 335 ~ 340 at some power settings. The lowest I can maintain is about 310.
I have tilted the carb, divided the intake elbow, changed the Ram Air Ducts, added baffles and I am still baffled : )
One day I would like to just get in the plane and enjoy the ride without having to be constantly watching what the temps are doing and I would like for my engine to last to TBO or at least near that.
Please comment on what your set up might be and the temps you are experiencing. What is acceptable on CHT for long term life of the engine??
Bobby
601 XL B
103 hrs. & still experimenting.
Jacksonville Fl.
-- Mark HubelbankNorthEast Monitoring2 Clock Tower PlaceSuite 555Maynard, MA, 01754 - USAmhubel(at)nemon.com (mhubel(at)nemon.com)978-443-3955[b]
| | - The Matronics JabiruEngine-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?JabiruEngine-List |
|
|
|
| Back to top |
|
|
mhubel
Joined: 05 Sep 2009
Posts: 141
|
| Posted: Fri Oct 22, 2010 9:57 am Post subject: Temps |
|
|
Marvin,
Typically I reduce throttle to 2800-2900 RPM by the time I get to 1000 feet AGL Then if not staying in the pattern, I will initially lean until EGT goes up to in the 1300-1350 range. This results in a fuel flow rate of 6 GPH or a bit less depending on chosen RPM. Most of the time it is more like 5.5-5.7 GPH. In theory 6 GPH is 75% power. I have just started working on lean of peak settings so I don't have much to say yet. So far it seems to come in at 5 or a bit under 5 GPH.
If the wind ever lets up here, I will get a better set of numbers. It has been a bit hard to hold a constant airspeed in the past few weeks.
On 10/22/2010 1:18 PM, Marvin Williams wrote: [quote] Mark, would you please elaborate on your leaning techniques? Specifically, at altitude and cruise power, what EGTs do you lean to?
Thanks,
marvin
N250MR
J250... 3300... w/ TBI40
From: Mark Hubelbank <mhubel(at)nemon.com> (mhubel(at)nemon.com)
To: jabiruengine-list(at)matronics.com (jabiruengine-list(at)matronics.com)
Sent: Fri, October 22, 2010 8:32:03 AM
Subject: Re: Temps
Bobby,
Others may have this working but I never got a Bing to work in the CH601 airframe. The right angle bend of the airflow was just too much for it. I now have a TBI-40-3 (not S) mounted horizontally with a 2 inch spacer from the engine and so far it is an order of magnitude improvement. Of course, one can now set the mixture. I run it rich (EGT's around 1250 or below at high/full throttle) then lean it as soon as throttle is reduced. I have been posting pictures of this at photo.hubbles.com.
On 10/22/2010 10:02 AM, BobbyPaulk(at)comcast.net (BobbyPaulk(at)comcast.net) wrote: | Quote: | p {margin:0;} List,
I am reading all kinds of info on what is supposed to be but where is the info on what is the proper jetting. I am particularly interested in a Jabiru 3300 ( with Hydraulic lifters ) on a Zodiac 601 XL. I am running a 260 Main Jet and 290 Needle Jet. It still appears I am running too lean. The EGT's go way up at 2500 ~ 2600 RPM and the 100 LL is burning very light gray. Is anyone running larger jetting. How about a different needle??
I also heard of some changes in the intake manifold although I can not confirm what has been done if anything.
Also would like to know what is an allowable Cylinder Head Temperature. I have them all below 300 except #6.
It goes up to 335 ~ 340 at some power settings. The lowest I can maintain is about 310.
I have tilted the carb, divided the intake elbow, changed the Ram Air Ducts, added baffles and I am still baffled : )
One day I would like to just get in the plane and enjoy the ride without having to be constantly watching what the temps are doing and I would like for my engine to last to TBO or at least near that.
Please comment on what your set up might be and the temps you are experiencing. What is acceptable on CHT for long term life of the engine??
Bobby
601 XL B
103 hrs. & still experimenting.
Jacksonville Fl.
--
Mark Hubelbank
NorthEast Monitoring
2 Clock Tower Place
Suite 555
Maynard, MA, 01754 - USA
mhubel(at)nemon.com (mhubel(at)nemon.com)
978-443-3955
|
--
Mark Hubelbank
NorthEast Monitoring
2 Clock Tower Place
Suite 555
Maynard, MA, 01754 - USA
mhubel(at)nemon.com (mhubel(at)nemon.com)
978-443-3955[b]
| | - The Matronics JabiruEngine-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?JabiruEngine-List |
|
_________________
Mark Hubelbank
N708HU
CH601XL
Jabiru 3300
Rotec TBI 40-3 carb
Sensenich ground adj prop.
240 hr TAF
Pictures at photo.hubbles.com |
|
| Back to top |
|
|
marvinlnaz(at)yahoo.com
Guest
|
| Posted: Fri Oct 22, 2010 10:25 am Post subject: Temps |
|
|
Thanks Mark,
I fully understand the difficulty in holding steady RPMs in turbulence! Experience the same myself.
I am really interested in seeing your EGT spread at altitude and cruise power when you get a chance to establish that data.
FWIW, I lean our TBI to 1382 deg F on the hottest cylinder and then live with whatever the others are. EGT spread at altitude is typically around 90 deg F.
I'll be looking for any farther info you post.
Marvin
From: Mark Hubelbank <mhubel(at)nemon.com>
To: jabiruengine-list(at)matronics.com
Sent: Fri, October 22, 2010 10:54:36 AM
Subject: Re: Temps
Marvin,
Typically I reduce throttle to 2800-2900 RPM by the time I get to 1000 feet AGL Then if not staying in the pattern, I will initially lean until EGT goes up to in the 1300-1350 range. This results in a fuel flow rate of 6 GPH or a bit less depending on chosen RPM. Most of the time it is more like 5.5-5.7 GPH. In theory 6 GPH is 75% power. I have just started working on lean of peak settings so I don't have much to say yet. So far it seems to come in at 5 or a bit under 5 GPH.
If the wind ever lets up here, I will get a better set of numbers. It has been a bit hard to hold a constant airspeed in the past few weeks.
On 10/22/2010 1:18 PM, Marvin Williams wrote: [quote] Mark, would you please elaborate on your leaning techniques? Specifically, at altitude and cruise power, what EGTs do you lean to?
Thanks,
marvin
N250MR
J250... 3300... w/ TBI40
From: Mark Hubelbank <mhubel(at)nemon.com> (mhubel(at)nemon.com)
To: jabiruengine-list(at)matronics.com (jabiruengine-list(at)matronics.com)
Sent: Fri, October 22, 2010 8:32:03 AM
Subject: Re: Temps
Bobby,
Others may have this working but I never got a Bing to work in the CH601 airframe. The right angle bend of the airflow was just too much for it. I now have a TBI-40-3 (not S) mounted horizontally with a 2 inch spacer from the engine and so far it is an order of magnitude improvement. Of course, one can now set the mixture. I run it rich (EGT's around 1250 or below at high/full throttle) then lean it as soon as throttle is reduced. I have been posting pictures of this at photo.hubbles.com.
On 10/22/2010 10:02 AM, BobbyPaulk(at)comcast.net (BobbyPaulk(at)comcast.net) wrote: | Quote: | p {margin:0;} List,
I am reading all kinds of info on what is supposed to be but where is the info on what is the proper jetting. I am particularly interested in a Jabiru 3300 ( with Hydraulic lifters ) on a Zodiac 601 XL. I am running a 260 Main Jet and 290 Needle Jet. It still appears I am running too lean. The EGT's go way up at 2500 ~ 2600 RPM and the 100 LL is burning very light gray. Is anyone running larger jetting. How about a different needle??
I also heard of some changes in the intake manifold although I can not confirm what has been done if anything.
Also would like to know what is an allowable Cylinder Head Temperature. I have them all below 300 except #6.
It goes up to 335 ~ 340 at some power settings. The lowest I can maintain is about 310.
I have tilted the carb, divided the intake elbow, changed the Ram Air Ducts, added baffles and I am still baffled : )
One day I would like to just get in the plane and enjoy the ride without having to be constantly watching what the temps are doing and I would like for my engine to last to TBO or at least near that.
Please comment on what your set up might be and the temps you are experiencing. What is acceptable on CHT for long term life of the engine??
Bobby
601 XL B
103 hrs. & still experimenting.
Jacksonville Fl.
-- Mark HubelbankNorthEast Monitoring2 Clock Tower PlaceSuite 555Maynard, MA, 01754 - USAmhubel(at)nemon.com (mhubel(at)nemon.com)978-443-3955 |
-- Mark HubelbankNorthEast Monitoring2 Clock Tower PlaceSuite 555Maynard, MA, 01754 - USAmhubel(at)nemon.com (mhubel(at)nemon.com)978-443-3955[b]
| | - The Matronics JabiruEngine-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?JabiruEngine-List |
|
|
|
| Back to top |
|
|
BobsV35B(at)aol.com
Guest
|
| Posted: Fri Oct 22, 2010 11:36 am Post subject: Temps |
|
|
Good Afternoon Mark,
May I suggest that you try leaning at cruising speeds by first finding the peak EGT on each of the cylinders. Check the fuel flow when at each peak. The fuel flow should have a spread of no more than a couple of tenths of a gallon from the first to peak to the last to peak. That is checking the general distribution pattern.
(Just as a note, the actual temperature is immaterial! It is the point where it reaches peak that we are interested in.)
Once you have fairly well balanced distribution, lean for about thirty degrees on the lean side of peak EGT. That is, if the peak EGT occurs at 1400 EGT, continue leaning until the EGT is at 1370. That will be very close to the best BSFC or the most power you can get out of each pound of fuel. Leaner loses efficiency and richer loses efficiency. If what you need is more power such as when you are climbing higher than ten or twelve thousand feet, lean to find peak EGT, then richen about fifty or sixty degrees rich of peak. That will get you the most power you can get for the amount of air being pumped.
You don't want to lean that way above about seventy-five percent power. It is the hottest place to operate your engine! Acceptable, even desirable, at seventy-five percent power or less. Not good at the higher power settings.
Personally I don't lean that way until I can no longer get much above sixty-five percent power. If you want to use more than seventy-five per cent power, you need to run at least 150, preferably 250 degrees F above peak EGT. At those higher power settings, we need the extra fuel to slow the burning rate so that we can avoid detonation.
Any help at all?
Happy Skies,
Old Bob
In a message dated 10/22/2010 12:57:21 P.M. Central Daylight Time, mhubel(at)nemon.com writes:
| Quote: | Marvin,
Typically I reduce throttle to 2800-2900 RPM by the time I get to 1000 feet AGL Then if not staying in the pattern, I will initially lean until EGT goes up to in the 1300-1350 range. This results in a fuel flow rate of 6 GPH or a bit less depending on chosen RPM. Most of the time it is more like 5.5-5.7 GPH. In theory 6 GPH is 75% power. I have just started working on lean of peak settings so I don't have much to say yet. So far it seems to come in at 5 or a bit under 5 GPH.
If the wind ever lets up here, I will get a better set of numbers. It has been a bit hard to hold a constant airspeed in the past few weeks.
On 10/22/2010 1:18 PM, Marvin Williams wrote: | Quote: | Mark, would you please elaborate on your leaning techniques? Specifically, at altitude and cruise power, what EGTs do you lean to?
Thanks,
marvin
N250MR
J250... 3300... w/ TBI40
From: Mark Hubelbank <mhubel(at)nemon.com> (mhubel(at)nemon.com)
To: jabiruengine-list(at)matronics.com (jabiruengine-list(at)matronics.com)
Sent: Fri, October 22, 2010 8:32:03 AM
Subject: Re: Temps
Bobby,
Others may have this working but I never got a Bing to work in the CH601 airframe. The right angle bend of the airflow was just too much for it. I now have a TBI-40-3 (not S) mounted horizontally with a 2 inch spacer from the engine and so far it is an order of magnitude improvement. Of course, one can now set the mixture. I run it rich (EGT's around 1250 or below at high/full throttle) then lean it as soon as throttle is reduced. I have been posting pictures of this at photo.hubbles.com.
On 10/22/2010 10:02 AM, BobbyPaulk(at)comcast.net (BobbyPaulk(at)comcast.net) wrote: | Quote: | p {margin:0;} List,
I am reading all kinds of info on what is supposed to be but where is the info on what is the proper jetting. I am particularly interested in a Jabiru 3300 ( with Hydraulic lifters ) on a Zodiac 601 XL. I am running a 260 Main Jet and 290 Needle Jet. It still appears I am running too lean. The EGT's go way up at 2500 ~ 2600 RPM and the 100 LL is burning very light gray. Is anyone running larger jetting. How about a different needle??
I also heard of some changes in the intake manifold although I can not confirm what has been done if anything.
Also would like to know what is an allowable Cylinder Head Temperature. I have them all below 300 except #6.
It goes up to 335 ~ 340 at some power settings. The lowest I can maintain is about 310.
I have tilted the carb, divided the intake elbow, changed the Ram Air Ducts, added baffles and I am still baffled : )
One day I would like to just get in the plane and enjoy the ride without having to be constantly watching what the temps are doing and I would like for my engine to last to TBO or at least near that.
Please comment on what your set up might be and the temps you are experiencing. What is acceptable on CHT for long term life of the engine??
Bobby
601 XL B
103 hrs. & still experimenting.
Jacksonville Fl.
--
Mark Hubelbank
NorthEast Monitoring
2 Clock Tower Place
Suite 555
Maynard, MA, 01754 - USA
mhubel(at)nemon.com (mhubel(at)nemon.com)
978-443-3955
|
--
Mark Hubelbank
NorthEast Monitoring
2 Clock Tower Place
Suite 555
Maynard, MA, 01754 - USA
mhubel(at)nemon.com (mhubel(at)nemon.com)
978-443-3955
====================================
List href="http://www.matronics.com/Navigator?JabiruEngine-List">http://www.matronics.com/Navigator?JabiruEngine-List
====================================
ms.matronics.com/">http://forums.matronics.com
====================================
tp://www.matronics.com/contribution">http://www.matronics.com/contribution
====================================
|
|
[quote][b]
| | - The Matronics JabiruEngine-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?JabiruEngine-List |
|
|
|
| Back to top |
|
|
mhubel
Joined: 05 Sep 2009
Posts: 141
|
| Posted: Fri Oct 22, 2010 12:55 pm Post subject: Temps |
|
|
Bob,
In my previous PA24-260 (Lycoming IO540) I did something close to what you are describing except I tended to keep it rich above 70% power instead of 75%. Typically that plane was flown at 65% power.
For the moment, given the temperature recommendations from Jabiru which are quite different from those from Lycoming or Contental, I am temporarily sticking to absolute temperatures. Although EGT can be questionable to measure in an absolute sense, today's instruments are better and with careful placement of probes there is a little hope. Mostly these settings are at least as conservative as the difference from peak method. At least they are with the TBI-40-3 I am using.
Also with the Jabiru, I don't like to have the EGT around peak with power above 60% even long enough to get good stable values across all cylinders.
Weather has been getting in the way of a careful lean of peak analysis.
With the Bing, the temperatues were so unstable that any measure was not meaningful. I think that was due to the very small space available for the right angle bend in the air intake but I gave up trying to make the Bing work acceptably.
On 10/22/2010 3:14 PM, BobsV35B(at)aol.com (BobsV35B(at)aol.com) wrote: [quote] Good Afternoon Mark,
May I suggest that you try leaning at cruising speeds by first finding the peak EGT on each of the cylinders. Check the fuel flow when at each peak. The fuel flow should have a spread of no more than a couple of tenths of a gallon from the first to peak to the last to peak. That is checking the general distribution pattern.
(Just as a note, the actual temperature is immaterial! It is the point where it reaches peak that we are interested in.)
Once you have fairly well balanced distribution, lean for about thirty degrees on the lean side of peak EGT. That is, if the peak EGT occurs at 1400 EGT, continue leaning until the EGT is at 1370. That will be very close to the best BSFC or the most power you can get out of each pound of fuel. Leaner loses efficiency and richer loses efficiency. If what you need is more power such as when you are climbing higher than ten or twelve thousand feet, lean to find peak EGT, then richen about fifty or sixty degrees rich of peak. That will get you the most power you can get for the amount of air being pumped.
You don't want to lean that way above about seventy-five percent power. It is the hottest place to operate your engine! Acceptable, even desirable, at seventy-five percent power or less. Not good at the higher power settings.
Personally I don't lean that way until I can no longer get much above sixty-five percent power. If you want to use more than seventy-five per cent power, you need to run at least 150, preferably 250 degrees F above peak EGT. At those higher power settings, we need the extra fuel to slow the burning rate so that we can avoid detonation.
Any help at all?
Happy Skies,
Old Bob
In a message dated 10/22/2010 12:57:21 P.M. Central Daylight Time, mhubel(at)nemon.com (mhubel(at)nemon.com) writes:
| Quote: | Marvin,
Typically I reduce throttle to 2800-2900 RPM by the time I get to 1000 feet AGL Then if not staying in the pattern, I will initially lean until EGT goes up to in the 1300-1350 range. This results in a fuel flow rate of 6 GPH or a bit less depending on chosen RPM. Most of the time it is more like 5.5-5.7 GPH. In theory 6 GPH is 75% power. I have just started working on lean of peak settings so I don't have much to say yet. So far it seems to come in at 5 or a bit under 5 GPH.
If the wind ever lets up here, I will get a better set of numbers. It has been a bit hard to hold a constant airspeed in the past few weeks.
On 10/22/2010 1:18 PM, Marvin Williams wrote: | Quote: | Mark, would you please elaborate on your leaning techniques? Specifically, at altitude and cruise power, what EGTs do you lean to?
Thanks,
marvin
N250MR
J250... 3300... w/ TBI40
From: Mark Hubelbank <mhubel(at)nemon.com> (mhubel(at)nemon.com)
To: jabiruengine-list(at)matronics.com (jabiruengine-list(at)matronics.com)
Sent: Fri, October 22, 2010 8:32:03 AM
Subject: Re: Temps
Bobby,
Others may have this working but I never got a Bing to work in the CH601 airframe. The right angle bend of the airflow was just too much for it. I now have a TBI-40-3 (not S) mounted horizontally with a 2 inch spacer from the engine and so far it is an order of magnitude improvement. Of course, one can now set the mixture. I run it rich (EGT's around 1250 or below at high/full throttle) then lean it as soon as throttle is reduced. I have been posting pictures of this at photo.hubbles.com.
On 10/22/2010 10:02 AM, BobbyPaulk(at)comcast.net (BobbyPaulk(at)comcast.net) wrote: | Quote: | p {margin:0;} List,
I am reading all kinds of info on what is supposed to be but where is the info on what is the proper jetting. I am particularly interested in a Jabiru 3300 ( with Hydraulic lifters ) on a Zodiac 601 XL. I am running a 260 Main Jet and 290 Needle Jet. It still appears I am running too lean. The EGT's go way up at 2500 ~ 2600 RPM and the 100 LL is burning very light gray. Is anyone running larger jetting. How about a different needle??
I also heard of some changes in the intake manifold although I can not confirm what has been done if anything.
Also would like to know what is an allowable Cylinder Head Temperature. I have them all below 300 except #6.
It goes up to 335 ~ 340 at some power settings. The lowest I can maintain is about 310.
I have tilted the carb, divided the intake elbow, changed the Ram Air Ducts, added baffles and I am still baffled : )
One day I would like to just get in the plane and enjoy the ride without having to be constantly watching what the temps are doing and I would like for my engine to last to TBO or at least near that.
Please comment on what your set up might be and the temps you are experiencing. What is acceptable on CHT for long term life of the engine??
Bobby
601 XL B
103 hrs. & still experimenting.
Jacksonville Fl.
--
Mark Hubelbank
NorthEast Monitoring
2 Clock Tower Place
Suite 555
Maynard, MA, 01754 - USA
mhubel(at)nemon.com (mhubel(at)nemon.com)
978-443-3955
|
--
Mark Hubelbank
NorthEast Monitoring
2 Clock Tower Place
Suite 555
Maynard, MA, 01754 - USA
mhubel(at)nemon.com (mhubel(at)nemon.com)
978-443-3955
====================================
List href="http://www.matronics.com/Navigator?JabiruEngine-List">http://www.matronics.com/Navigator?JabiruEngine-List
====================================
ms.matronics.com/">http://forums.matronics.com
====================================
tp://www.matronics.com/contribution">http://www.matronics.com/contribution
====================================
|
|
--
Mark Hubelbank
NorthEast Monitoring
2 Clock Tower Place
Suite 555
Maynard, MA, 01754 - USA
mhubel(at)nemon.com (mhubel(at)nemon.com)
978-443-3955[b]
| | - The Matronics JabiruEngine-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?JabiruEngine-List |
|
_________________
Mark Hubelbank
N708HU
CH601XL
Jabiru 3300
Rotec TBI 40-3 carb
Sensenich ground adj prop.
240 hr TAF
Pictures at photo.hubbles.com |
|
| Back to top |
|
|
Lynn Matteson
Joined: 10 Jan 2006
Posts: 2778
Location: Grass Lake, Michigan
|
| Posted: Sat Oct 23, 2010 2:00 am Post subject: Temps |
|
|
Bob-
Just to clarify, when you said: " If you want to use more than
seventy-five per cent power, you need to run at least 150, preferably
250 degrees F above peak EGT. At those higher power settings, we need
the extra fuel to slow the burning rate so that we can avoid
detonation," I'm sure you meant to say **150, preferable 250 degrees
richer (or cooler) than peak EGT** didn't you?
Mark, Bob, and others-
Where are you getting the figures for the percentages of power?
Everybody talks about these percentages, but I don't see the flows,
the manifold pressure numbers, or whatever the criteria is for
establishing these percentages written as it pertains to the Jabiru
line of engines.
Lynn Matteson
Kitfox IV Speedster, taildragger
Jabiru 2200, #2062
Sensenich 62"x46" Wood (summer)
Electroair direct-fire ignition system
Rotec TBI-40 injection
Status: flying...1054 hrs (since 3-27-2006)
| | - The Matronics JabiruEngine-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?JabiruEngine-List |
|
_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM |
|
| Back to top |
|
|
BobsV35B(at)aol.com
Guest
|
| Posted: Sat Oct 23, 2010 5:09 am Post subject: Temps |
|
|
Good Morning Lynn,
Yes! Glad you caught that. I was thinking about needing more fuel, but I sure did not get it written that way!
The reason we want to be that rich is so that the rate of burn (Actually it is a bit more complicated because the burn is just as fast but the fuel takes longer to get burning that fast).is slower. That moves the point of peak cylinder pressure further along on the stroke and reduces the peak cylinder pressure. The actual temperature of the EGT is immaterial. It is just that EGT is a good, low cost, and convenient, indicator of what is happening to the combustion process.
They key is to control that peak cylinder pressure.
The history of using EGT as an indicator is all about how Al Hundere brought us to using his ALCOR unit (Al's Corporation.)
He was trying to figure out some way to add a torque meter to our small engines when he noted the variances of the EGT on his dynamometer. He noted that while the EGT gauges of the day were not extremely accurate, they did indicate the peak quite accurately. By advising us to run richer or leaner than peak EGT he gave us the same information as was used in those big round engines that were equipped with torquemeters. That is why ALCOR never used precise temperatures. The actual EGT temperature means nothing. It is it's relation to peak EGT that tells us where the compression process is going. What we really want to know is where the mixture is in relation to best power mixture!
Does that help a bit or have I muddied the water again? <G>
As to where the numbers come from for the Jabiru, in my case it is a WAG based on the principle that all internal combustion engines run the same and are affected the same way, but our aircraft engines are all designed to run rich to cool properly at full power and to cool properly at cruise power using best power mixtures.
That is why Continental says to run rich above sixty-five per cent power and Lycoming uses seventy-five percent. If you try to nail either's engineers down to something more precise, they will tell you it all depends and my WAG is that the JABIRU engineers went through the same process as did the others.
Happy Skies,
Old Bob
In a message dated 10/23/2010 5:01:08 A.M. Central Daylight Time, lynnmatt(at)jps.net writes:
| Quote: | --> JabiruEngine-List message posted by: Lynn Matteson <lynnmatt(at)jps.net>
Bob-
Just to clarify, when you said: " If you want to use more than
seventy-five per cent power, you need to run at least 150, preferably
250 degrees F above peak EGT. At those higher power settings, we need
the extra fuel to slow the burning rate so that we can avoid
detonation," I'm sure you meant to say **150, preferable 250 degrees
richer (or cooler) than peak EGT** didn't you?
Mark, Bob, and others-
Where are you getting the figures for the percentages of power?
Everybody talks about these percentages, but I don't see the flows,
the manifold pressure numbers, or whatever the criteria is for
establishing these percentages written as it pertains to the Jabiru
line of engines.
Lynn Matteson
Kitfox IV Speedster, taildragger
Jabiru 2200, #2062
Sensenich 62"x46" Wood (summer)
Electroair direct-fire ignition system
Rotec TBI-40 injection
Status: flying...1054 hrs (since ===============================================
_-= = Use utilities Day ================================================ - MATRONICS WEB FORUMS ================================================ - List Contribution Web Site sp; ===================================================
|
[quote][b]
| | - The Matronics JabiruEngine-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?JabiruEngine-List |
|
|
|
| Back to top |
|
|
mhubel
Joined: 05 Sep 2009
Posts: 141
|
| Posted: Sat Oct 23, 2010 1:40 pm Post subject: Temps |
|
|
Lynn,
I don't have a manifold pressure indicator yet so I am going by
fuel burn. At best a spark ignition engine generates 15 HP per gal per
hour so at 6 GPH one at best is generating 90 HP which is 75% of 120 HP
(for a 3300). I am treating this as worst case and figure anytime it
won't nicely lean to 6 GPH or under, it has to run at the rich settings.
For a Jabiru, I then follow their recommendations and set the mixture
for 1250 F max. Even that is a moving target as it changes as one gains
altitude.
On 10/23/2010 5:58 AM, Lynn Matteson wrote:
| Quote: |
Bob-
Just to clarify, when you said: " If you want to use more than
seventy-five per cent power, you need to run at least 150, preferably
250 degrees F above peak EGT. At those higher power settings, we need
the extra fuel to slow the burning rate so that we can avoid
detonation," I'm sure you meant to say **150, preferable 250 degrees
richer (or cooler) than peak EGT** didn't you?
Mark, Bob, and others-
Where are you getting the figures for the percentages of power?
Everybody talks about these percentages, but I don't see the flows,
the manifold pressure numbers, or whatever the criteria is for
establishing these percentages written as it pertains to the Jabiru
line of engines.
Lynn Matteson
Kitfox IV Speedster, taildragger
Jabiru 2200, #2062
Sensenich 62"x46" Wood (summer)
Electroair direct-fire ignition system
Rotec TBI-40 injection
Status: flying...1054 hrs (since 3-27-2006)
|
--
Mark Hubelbank
NorthEast Monitoring
2 Clock Tower Place
Suite 555
Maynard, MA, 01754 - USA
mhubel(at)nemon.com
978-443-3955
| | - The Matronics JabiruEngine-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?JabiruEngine-List |
|
_________________
Mark Hubelbank
N708HU
CH601XL
Jabiru 3300
Rotec TBI 40-3 carb
Sensenich ground adj prop.
240 hr TAF
Pictures at photo.hubbles.com |
|
| Back to top |
|
|
BobsV35B(at)aol.com
Guest
|
| Posted: Sat Oct 23, 2010 3:47 pm Post subject: Temps |
|
|
Good Evening Mark,
I think your 15 HP per gal of fuel is a good number for an engine with a compression ratio of at least 8.5 to one if it also has very good fuel distribution to each cylinder. If there is any unbalance in the amount of fuel per cylinder, that ideal power per gallon of fuel cannot be reached.
Lower compression ratios will mean substantially less horsepower for each gallon of fuel used.
One simple way of checking for balanced fuel mixtures with a fixed pitch propellor is to lean for a drop in RPM. Starting at full rich and leaning the engine should result in a slight increase in RPM. once the peak RPM is reached, further leaning will cause a drop in RPM. For an engine the size and RPM range of the Jabiru, a drop of at least one hundred RPM before any roughness is noted signifies good distribution. With excellent distribution, the rpm drop could be a couple of hundred RPM. If you can discern no increase in RPM before roughness ensues, The distribution stinks and you will get way less than 15 HP per gallon of fuel.
The Jabiru that I fly has a Bing carburetor and we have no way of manually adjusting the mixture. Any changes have to be done by changing out the fuel rods and jets.
There is no easy way to analyze the Bing equipped Jabiru, but with careful analysis of a good six cylinder engine monitor, some conclusions can be reached.
It is NOT a simple process.
It would not be at all unusual for an engine equipped with a Bing to develop as little as ten HP per gallon of fuel.
I envy Lynn's adjustable mixture capability! <G>
As Always, It All Depends.
Happy Skies,
Old Bob
In a message dated 10/23/2010 4:40:43 P.M. Central Daylight Time, mhubel(at)nemon.com writes:
| Quote: | --> JabiruEngine-List message posted by: Mark Hubelbank <mhubel(at)nemon.com>
Lynn,
I don't have a manifold pressure indicator yet so I am going by
fuel burn. At best a spark ignition engine generates 15 HP per gal per
hour so at 6 GPH one at best is generating 90 HP which is 75% of 120 HP
(for a 3300). I am treating this as worst case and figure anytime it
won't nicely lean to 6 GPH or under, it has to run at the rich settings.
For a Jabiru, I then follow their recommendations and set the mixture
for 1250 F max. Even that is a moving target as it changes as one gains
altitude.
On 10/23/2010 5:58 AM, Lynn Matteson wrote:
| Quote: | --> JabiruEngine-List message posted by: Lynn Matteson <lynnmatt(at)jps.net>
Bob-
Just to clarify, when you said: " If you want to use more than
seventy-five per cent power, you need to run at least 150, preferably
250 degrees F above peak EGT. At those higher power settings, we need
the extra fuel to slow the burning rate so that we can avoid
detonation," I'm sure you meant to say **150, preferable 250 degrees
richer (or cooler) than peak EGT** didn't you?
Mark, Bob, and others-
Where are you getting the figures for the percentages of power?
Everybody talks about these percentages, but I don't see the flows,
the manifold pressure numbers, or whatever the criteria is for
establishing these percentages written as it pertains to the Jabiru
line of engines.
Lynn Matteson
Kitfox IV Speedster, taildragger
Jabiru 2200, #2062
Sensenich 62"x46" Wood (summer)
Electroair direct-fire ignition system
Rotec TBI-40 injection
Status: flying...1054 hrs (since 3-27-2006)
|
|
[quote][b]
| | - The Matronics JabiruEngine-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?JabiruEngine-List |
|
|
|
| Back to top |
|
|
dons701
Joined: 22 May 2009
Posts: 80
Location: Hershey, PA
|
| Posted: Sun Oct 24, 2010 7:22 am Post subject: Re: Temps |
|
|
Hello Bob
I have seen one way to lean the Bing that looks simple. It is to controllably "leak" filtered air into the vacuum port near the idle mixture screw. The filtered air was drawn from a tee in the sense hose line of the Bing, through a small needle valve located on the inst. panel, then to the vacuum port. Full rich when the valve is closed. Perhaps, anyone who has tried this will kindly tell us all how well this is working.... Don
| | - The Matronics JabiruEngine-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?JabiruEngine-List |
|
_________________
Zenith 701 #76120
Jabiru 2200A #2456 95 hours
Sensenich Wood 64-PJ-36 Prop |
|
| Back to top |
|
|
BobsV35B(at)aol.com
Guest
|
| Posted: Sun Oct 24, 2010 8:01 am Post subject: Temps |
|
|
Good Morning Don,
That is way out of my paygrade, but I sure would like to hear more about it.
Thanks
And;
Happy Skies,
Old Bob
In a message dated 10/24/2010 10:25:34 A.M. Central Daylight Time, burdon1(at)comcast.net writes:
| Quote: | --> JabiruEngine-List message posted by: "dons701" <burdon1(at)comcast.net>
Hello Bob
I have seen one way to lean the Bing that looks simple. It is to controllably "leak" filtered air into the vacuum port near the idle mixture screw. The filtered air was drawn from a tee in the sense hose line of the Bing, through a small needle valve located on the inst. panel, then to the vacuum port. Full rich when the valve is closed. Perhaps, anyone who has tried this will kindly tell us all how well this is working.... Don
--------
Zenith 701 #76120
Jabiru 2200A #2456 67 hours
Sensenich Wood 64-PJ-36 Prop
|
[quote][b]
| | - The Matronics JabiruEngine-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?JabiruEngine-List |
|
|
|
| Back to top |
|
|
Lynn Matteson
Joined: 10 Jan 2006
Posts: 2778
Location: Grass Lake, Michigan
|
| Posted: Sun Oct 24, 2010 8:13 am Post subject: Temps |
|
|
This is *apparently* the thinking behind the Hacman device. I've seen
several people mimic this idea, and they tell me that it works
reasonably well.
Lynn Matteson
Kitfox IV Speedster, taildragger
Jabiru 2200, #2062
Sensenich 62"x46" Wood (summer)
Electroair direct-fire ignition system
Rotec TBI-40 injection
Status: flying...1060 hrs (since 3-27-2006)
On Oct 24, 2010, at 11:22 AM, dons701 wrote:
| Quote: |
<burdon1(at)comcast.net>
Hello Bob
I have seen one way to lean the Bing that looks simple. It is to
controllably "leak" filtered air into the vacuum port near the idle
mixture screw. The filtered air was drawn from a tee in the sense
hose line of the Bing, through a small needle valve located on the
inst. panel, then to the vacuum port. Full rich when the valve is
closed. Perhaps, anyone who has tried this will kindly tell us all
how well this is working.... Don
--------
Zenith 701 #76120
Jabiru 2200A #2456 67 hours
Sensenich Wood 64-PJ-36 Prop
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=316862#316862
|
| | - The Matronics JabiruEngine-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?JabiruEngine-List |
|
_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM |
|
| Back to top |
|
|
|
|
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum
|
Powered by phpBB © 2001, 2005 phpBB Group
|
Get Email Distribution Too!
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
