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Float Flyr
Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland
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 Posted: Mon Aug 24, 2009 7:17 pm Post subject: ROP versus LOP...might be off-topic for some |
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Lynn:
For what it's worth my training told me that LOP is ok as long as you are
not drawing any power. If you are in a situation where power has to be
pulled you are better off at ROP. If you are constantly running LOP keep a
close eye on the top of your pistons.
Noel
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_________________
Noel Loveys
Kitfox III-A
Aerocet 1100 Floats |
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BobsV35B(at)aol.com
Guest
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| Posted: Mon Aug 24, 2009 7:38 pm Post subject: ROP versus LOP...might be off-topic for some |
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Good Evening Noel,
Could you define what you mean by "pulling power".
Continental Motors generally suggests that lean side operations be restricted to sixty-five percent of maximum rated power. Lycoming generally uses a figure of seventy-five percent for the same purpose. Both manufacturers have a considerable number of restrictions as to when and how to run lean.
There are many text books that delve into lean side operations.
Curtiss Wright Corporation has given us about the most extensive guidance I have ever seen as to the "How Too's" of large radial engines.
Advanced Pilot Seminars of Ada, Oklahoma, teach a course of engine management which uses Continental, Lycoming and Curtiss Wright data to teach what really is happening at various power settings.
At very high power settings, (above sixty-five to seventy-five percent of maximum continuous horsepower)extra fuel is used by most aircraft engine manufacturers to move the peak cylinder pressures to a point where adequate cooling can be provided.
That data correlates well with data given by both Lycoming and Continental.
When does your training say that lean side operation is acceptable?
Happy Skies,
Old Bob
In a message dated 8/24/2009 10:18:24 P.M. Central Daylight Time, noelloveys(at)yahoo.ca writes:
| Quote: | --> JabiruEngine-List message posted by: "Noel Loveys" <noelloveys(at)yahoo.ca>
Lynn:
For what it's worth my training told me that LOP is ok as long as you are
not drawing any power. If you are in a situation where power has to be
pulled you are better off at ROP. If you are constantly running LOP keep a
close eye on the top of your pistons.
Noel
-----Original Message-----
From: owner-jabiruengine-list-server(at)matronics.com
[mailto:owner-jabiruengine-list-server(at)matronics.com] On Behalf Of Lynn
Matteson
Sent: Saturday, August 15, 2009 3:45 PM
To: jabiruengines(at)yahoogroups.com; kitfox-list(at)matronics.com;
jabiruengine-list(at)matronics.com
Subject: ROP versus LOP...might be off-topic for some
--> JabiruEngine-List message posted by: Lynn Matteson <lynnmatt(at)jps.net>
Over the last week, I've had some fun making some tests with my newly-
installed Rotec TBI-40 mixture-adjustable, carburetor-replacement
device on my Jabiru engine. I don't know whether two of these units
will work on a Rotax, so many of you might want to hit the delete key
right now.
For the most part, I was flying it LOP (lean-of-peak), but yesterday
I made a flight and decided that I would try ROP (rich-of-peak). In
flying LOP, the articles I've read say to keep the power requirements
low, and LOP will work and you won't burn the engine down. I was
amazed that this LOP thing even works at all, let alone work as well
as I've found that it seems too....I guess I'm still a bit of a
skeptic. After all, if going lean is a bad thing, how can going even
leaner be a good thing? I won't argue whether or not it's a good or
bad thing, and there are those of you that may not be able to do any
leaning at all, as I was until I got this unit.
Three days ago, I made two trips totaling 475 miles, using LOP
settings, and yesterday I made a 310-mile trip, using ROP settings. I
had flown the 475 miles leaning out the engine until peak EGT, then
leaning more until the engine was obviously low on power, and I
contentedly flew at this setting, watching the scenery crawl by.
Yesterday I decided to actually GO somewhere, and never mind the fuel
saving, I just wanted to get there, so I decided to try ROP.
Here are the average numbers from those trips:
LOP: 27.77 miles per gallon; 3.3 gallons per hour; 93.14
miles per hour
ROP: 23.66 miles per gallon; 4.37 gallons per hour; 103.3 miles per
hour
Altitudes on all of these flight were anywhere from 3000' MSL (with a
base of 1000') to 10,000 MSL, with throttle settings from 2600 rpm to
3050. Fuel flow as seen on the gauge, ranged from 2.5 gallons per
hour to 5.0 not including takeoffs, but including climbs.
So you can see from these figures (admittedly a low number of
samples) that it does pay to tweak the mixture, and even if flown
LOP, the speed is not too bad.
Lynn Matteson
Kitfox IV Speedster, taildragger
Jabiru 2200, #2062, 737.3 hrs
Sensenich 62"x46" Wood prop
Electroair direct-fire ignition system
Rotec TBI-40 injection
Status: ================================================= Use utilities Day ================================================ - MATRONICS WEB FORUMS ================================================ - List Contribution Web Site sp; ===================================================
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[quote][b]
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Lynn Matteson
Joined: 10 Jan 2006
Posts: 2778
Location: Grass Lake, Michigan
|
| Posted: Tue Aug 25, 2009 2:38 am Post subject: ROP versus LOP...might be off-topic for some |
|
|
Exactly, Noel. In all the readings I've done over the last couple of
weeks, that is the MOST- often repeated caveat...."don't try LOP when
pulling power". The power will fall off even if in a cruise
situation, so this operating at "lean of peak EGT" is only for
cruising. I've read a lot about it in John Deakin's articles on
AVweb.com. I'm surprised that this has been around for so long, and I
hadn't heard about it until now. I only heard about it a few weeks
ago, and then did a search for "lean of peak" on google, and found
thousands of articles. Another warning is that we have all cylinders
monitored for EGT and CHT when trying to run LOP. And of course, the
engine has to be capable of mixture control. Mine wasn't until I
installed the Rotec TBI-40 with its mixture control. Stuck with a
Bing, I wasn't able to try this operation.
Lynn Matteson
Kitfox IV Speedster, taildragger
Jabiru 2200, #2062, 742.8 hrs
Sensenich 62"x46" Wood prop
Electroair direct-fire ignition system
Rotec TBI-40 injection
Status: flying
On Aug 24, 2009, at 11:14 PM, Noel Loveys wrote:
[quote]
<noelloveys(at)yahoo.ca>
Lynn:
For what it's worth my training told me that LOP is ok as long as
you are
not drawing any power. If you are in a situation where power has
to be
pulled you are better off at ROP. If you are constantly running
LOP keep a
close eye on the top of your pistons.
Noel
--
| | - 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 |
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Float Flyr
Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland
|
| Posted: Tue Aug 25, 2009 10:12 am Post subject: ROP versus LOP...might be off-topic for some |
|
|
Increasing throttle under load
So basically what I was saying was the same thing as Continental and Lycoming… Stay rich of peak when you need lots of power. Lean of Peak should be reserved basically for long descents at lower throttle settings, taxiing or possibly endurance flight.
When I was in flight school the school instructed me to always lean the engine LOP except for takeoff which we used full throttle for a lot of the training exercises that was ok but we cruised the C172 at close to 75% throttle. On solo flights I always ran ROP except if I was doing a long decent of say five minutes or more. Once in the landing circuit I always went full rich to be ready to draw power for a go around.
Most of the carbs are set up to run the engine a little rich at idle to make them easier to start. While warming up an engine or taxiing I usually mixed LOP. Part of the checklist turning onto the runway was to mix full rich… The field was on a plateau 400 ft msl.
A lot of the instructors and students didn’t use the same fuel management on the ground as I did and as far as I can see the paid for it fouled plugs. On one occasion I saw the plane I was about to fly pull up to the fuel pumps spewing a fair bit of soot from the exhaust. I called the AME ( Aircraft Maintenance Engineer) lean the idle mixture a bit. For a week the engine ran great but one student just couldn’t get it started after a cold night so they enrichened it again until we got warmer weather.
I’m not sure if the flight school wanted to keep me or kill me. Almost every flight I would find snags in the plane. Low tires, crud build up on the control hinges and spinner problems were all cleared in short order. That may have been why they always scheduled me to fly at daybreak… The plane wouldn’t see and engineer until my next flight. I also noticed the instructors would stick close to the other students during their walk around but in my case they only checked the fuel caps were in place….
Noel
From: owner-jabiruengine-list-server(at)matronics.com [mailto:owner-jabiruengine-list-server(at)matronics.com] On Behalf Of BobsV35B(at)aol.com
Sent: Tuesday, August 25, 2009 1:08 AM
To: jabiruengine-list(at)matronics.com
Subject: Re: ROP versus LOP...might be off-topic for some
Good Evening Noel,
Could you define what you mean by "pulling power".
Continental Motors generally suggests that lean side operations be restricted to sixty-five percent of maximum rated power. Lycoming generally uses a figure of seventy-five percent for the same purpose. Both manufacturers have a considerable number of restrictions as to when and how to run lean.
There are many text books that delve into lean side operations.
Curtiss Wright Corporation has given us about the most extensive guidance I have ever seen as to the "How Too's" of large radial engines.
Advanced Pilot Seminars of Ada, Oklahoma, teach a course of engine management which uses Continental, Lycoming and Curtiss Wright data to teach what really is happening at various power settings.
At very high power settings, (above sixty-five to seventy-five percent of maximum continuous horsepower)extra fuel is used by most aircraft engine manufacturers to move the peak cylinder pressures to a point where adequate cooling can be provided.
That data correlates well with data given by both Lycoming and Continental.
When does your training say that lean side operation is acceptable?
Happy Skies,
Old Bob
In a message dated 8/24/2009 10:18:24 P.M. Central Daylight Time, noelloveys(at)yahoo.ca writes:
[quote]
--> JabiruEngine-List message posted by: "Noel Loveys" <noelloveys(at)yahoo.ca>
Lynn:
For what it's worth my training told me that LOP is ok as long as you are
not drawing any power. If you are in a situation where power has to be
pulled you are better off at ROP. If you are constantly running LOP keep a
close eye on the top of your pistons.
Noel
--
| | - 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 |
|
_________________
Noel Loveys
Kitfox III-A
Aerocet 1100 Floats |
|
| Back to top |
|
|
BobsV35B(at)aol.com
Guest
|
| Posted: Tue Aug 25, 2009 12:16 pm Post subject: ROP versus LOP...might be off-topic for some |
|
|
Good Afternoon Noel,
Do you generally cruise above seventy-five percent power?
If so, ROP is probably best unless you have a supercharger. Whole 'nother question.
Do you ever cruise above six thousand feet MSL?
If you do (with a normally aspirated engine) there is no way you could damage the engine with the mixture control regardless of what you did with it!
Personally, I find that the vast majority of my flying is done at power settings where LOP is by FAR the better way to go.
Very few flight training operations have the time or the inclination to teach proper engine operations for any regime other than the basic training operation. It is also very rare that any training operation will have instrumentation installed that will tell the pilot whether or not the fuel distribution is good enough to allow Lean Side Operations.
Individual airplanes of the same model and same vintage often vary widely as to fuel distribution. There are methods that can be used to determine fuel balance, but it gets quite time consuming to do so. Without good distribution, you can't take advantage of the lean side.
However, once we do have good distribution and lean side operations ARE practical, the benefits are great.
That is the beauty of a course such as is available from the Advanced Pilot Seminar folks. It teaches us first how to find out how the airplane we are flying works. It then tells us how to fix it if something is wrong.
As Lynn has told us, he was fortunate enough to read most of what John Deakin has written on the subject.
There are a lot of Old Wives Tales that are taught beginning students because there is not adequate time in the training syllabus to completely cover the issue.
If you include normal cross country flight as your definition of endurance flight and you don't go cross country, I guess you have little use for Lean Side operation, but I cannot imagine operating in any other way.
It does take training. There is no quick "cookie cutter" formula to tell us how to do it, but the benefits in longer engine life, cooler operations, and cleaner engine operations are worth the effort all by themselves.
The lower fuel costs and greater range available are just icing on the cake.
I never flew a piston engine airliner that was NOT operated in some form of lean side operation. For the short haul airplanes, it was "Auto Lean'. For long haul, especially when we had the services of a flight engineer, it was manually leaned well beyond the point of Auto Lean.
We now have the benefit of excellent low cost engine instrumentation to tell us what Lindbergh had to find out by lengthy bouts of experimentation, but the results have NOT changed since those days of long ago.
Leaner is Cooler and Leaner is Better!
I think Lynn is right on the true path to greater knowledge of how to properly, safely, and efficiently, operate his engine.
Make any sense at all?
Happy Skies,
Old Bob
In a message dated 8/25/2009 1:12:49 P.M. Central Daylight Time, noelloveys(at)yahoo.ca writes:
| Quote: |
Increasing throttle under load
So basically what I was saying was the same thing as Continental and Lycoming… Stay rich of peak when you need lots of power. Lean of Peak should be reserved basically for long descents at lower throttle settings, taxiing or possibly endurance flight.
When I was in flight school the school instructed me to always lean the engine LOP except for takeoff which we used full throttle for a lot of the training exercises that was ok but we cruised the C172 at close to 75% throttle. On solo flights I always ran ROP except if I was doing a long decent of say five minutes or more. Once in the landing circuit I always went full rich to be ready to draw power for a go around.
Most of the carbs are set up to run the engine a little rich at idle to make them easier to start. While warming up an engine or taxiing I usually mixed LOP. Part of the checklist turning onto the runway was to mix full rich… The field was on a plateau 400 ft msl.
A lot of the instructors and students didn’t use the same fuel management on the ground as I did and as far as I can see the paid for it fouled plugs. On one occasion I saw the plane I was about to fly pull up to the fuel pumps spewing a fair bit of soot from the exhaust. I called the AME ( Aircraft Maintenance Engineer) lean the idle mixture a bit. For a week the engine ran great but one student just couldn’t get it started after a cold night so they enrichened it again until we got warmer weather.
I’m not sure if the flight school wanted to keep me or kill me. Almost every flight I would find snags in the plane. Low tires, crud build up on the control hinges and spinner problems were all cleared in short order. That may have been why they always scheduled me to fly at daybreak… The plane wouldn’t see and engineer until my next flight. I also noticed the instructors would stick close to the other students during their walk around but in my case they only checked the fuel caps were in place….
Noel
From: owner-jabiruengine-list-server(at)matronics.com [mailto:owner-jabiruengine-list-server(at)matronics.com] On Behalf Of BobsV35B(at)aol.com
Sent: Tuesday, August 25, 2009 1:08 AM
To: jabiruengine-list(at)matronics.com
Subject: Re: ROP versus LOP...might be off-topic for some
Good Evening Noel,
Could you define what you mean by "pulling power".
Continental Motors generally suggests that lean side operations be restricted to sixty-five percent of maximum rated power. Lycoming generally uses a figure of seventy-five percent for the same purpose. Both manufacturers have a considerable number of restrictions as to when and how to run lean.
There are many text books that delve into lean side operations.
Curtiss Wright Corporation has given us about the most extensive guidance I have ever seen as to the "How Too's" of large radial engines.
Advanced Pilot Seminars of Ada, Oklahoma, teach a course of engine management which uses Continental, Lycoming and Curtiss Wright data to teach what really is happening at various power settings.
At very high power settings, (above sixty-five to seventy-five percent of maximum continuous horsepower)extra fuel is used by most aircraft engine manufacturers to move the peak cylinder pressures to a point where adequate cooling can be provided.
That data correlates well with data given by both Lycoming and Continental.
When does your training say that lean side operation is acceptable?
Happy Skies,
Old Bob
In a message dated 8/24/2009 10:18:24 P.M. Central Daylight Time, noelloveys(at)yahoo.ca writes:
| Quote: |
--> JabiruEngine-List message posted by: "Noel Loveys" <noelloveys(at)yahoo.ca>
Lynn:
For what it's worth my training told me that LOP is ok as long as you are
not drawing any power. If you are in a situation where power has to be
pulled you are better off at ROP. If you are constantly running LOP keep a
close eye on the top of your pistons.
Noel
-----Original Message-----
From: owner-jabiruengine-list-server(at)matronics.com
[mailto:owner-jabiruengine-list-server(at)matronics.com] On Behalf Of Lynn
Matteson
Sent: Saturday, August 15, 2009 3:45 PM
To: jabiruengines(at)yahoogroups.com; kitfox-list(at)matronics.com;
jabiruengine-list(at)matronics.com
Subject: ROP versus LOP...might be off-topic for some
--> JabiruEngine-List message posted by: Lynn Matteson <lynnmatt(at)jps.net>
Over the last week, I've had some fun making some tests with my newly-
installed Rotec TBI-40 mixture-adjustable, carburetor-replacement
device on my Jabiru engine. I don't know whether two of these units
will work on a Rotax, so many of you might want to hit the delete key
right now.
For the most part, I was flying it LOP (lean-of-peak), but yesterday
I made a flight and decided that I would try ROP (rich-of-peak). In
flying LOP, the articles I've read say to keep the power requirements
low, and LOP will work and you won't burn the engine down. I was
amazed that this LOP thing even works at all, let alone work as well
as I've found that it seems too....I guess I'm still a bit of a
skeptic. After all, if going lean is a bad thing, how can going even
leaner be a good thing? I won't argue whether or not it's a good or
bad thing, and there are those of you that may not be able to do any
leaning at all, as I was until I got this unit.
Three days ago, I made two trips totaling 475 miles, using LOP
settings, and yesterday I made a 310-mile trip, using ROP settings. I
had flown the 475 miles leaning out the engine until peak EGT, then
leaning more until the engine was obviously low on power, and I
contentedly flew at this setting, watching the scenery crawl by.
Yesterday I decided to actually GO somewhere, and never mind the fuel
saving, I just wanted to get there, so I decided to try ROP.
Here are the average numbers from those trips:
LOP: 27.77 miles per gallon; 3.3 gallons per hour; 93.14
miles per hour
ROP: 23.66 miles per gallon; 4.37 gallons per hour; 103.3 miles per
hour
Altitudes on all of these flight were anywhere from 3000' MSL (with a
base of 1000') to 10,000 MSL, with throttle settings from 2600 rpm to
3050. Fuel flow as seen on the gauge, ranged from 2.5 gallons per
hour to 5.0 not including takeoffs, but including climbs.
So you can see from these figures (admittedly a low number of
samples) that it does pay to tweak the mixture, and even if flown
LOP, the speed is not too bad.
Lynn Matteson
Kitfox IV Speedster, taildragger
Jabiru 2200, #2062, 737.3 hrs
Sensenich 62"x46" Wood prop
Electroair direct-fire ignition system
Rotec TBI-40 injection
Status: ======================== Use utilities Day ======================= - MATRONICS WEB FORUMS ======================= - List Contribution Web Site sp; =
|
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0123456789
0 |
[quote][b]
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http://www.matronics.com/Navigator?JabiruEngine-List |
|
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BobsV35B(at)aol.com
Guest
|
| Posted: Tue Aug 25, 2009 12:24 pm Post subject: ROP versus LOP...might be off-topic for some |
|
|
Good Afternoon Noel,
Do you generally cruise above seventy-five percent power?
If so, ROP is probably best unless you have a supercharger. Whole 'nother question.
Do you ever cruise above six thousand feet MSL?
If you do (with a normally aspirated engine) there is no way you could damage the engine with the mixture control regardless of what you did with it!
Personally, I find that the vast majority of my flying is done at power settings where LOP is by FAR the better way to go.
Very few flight training operations have the time or the inclination to teach proper engine operations for any regime other than the basic training operation. It is also very rare that any training operation will have instrumentation installed that will tell the pilot whether or not the fuel distribution is good enough to allow Lean Side Operations.
Individual airplanes of the same model and same vintage often vary widely as to fuel distribution. There are methods that can be used to determine fuel balance, but it gets quite time consuming to do so. Without good distribution, you can't take advantage of the lean side.
However, once we do have good distribution and lean side operations ARE practical, the benefits are great.
That is the beauty of a course such as is available from the Advanced Pilot Seminar folks. It teaches us first how to find out how the airplane we are flying works. It then tells us how to fix it if something is wrong.
As Lynn has told us, he was fortunate enough to read most of what John Deakin has written on the subject.
There are a lot of Old Wives Tales that are taught beginning students because there is not adequate time in the training syllabus to completely cover the issue.
If you include normal cross country flight as your definition of endurance flight and you don't go cross country, I guess you have little use for Lean Side operation, but I cannot imagine operating in any other way.
It does take training. There is no quick "cookie cutter" formula to tell us how to do it, but the benefits in longer engine life, cooler operations, and cleaner engine operations are worth the effort all by themselves.
The lower fuel costs and greater range available are just icing on the cake.
I never flew a piston engine airliner that was NOT operated in some form of lean side operation. For the short haul airplanes, it was "Auto Lean'. For long haul, especially when we had the services of a flight engineer, it was manually leaned well beyond the point of Auto Lean.
We now have the benefit of excellent low cost engine instrumentation to tell us what Lindbergh had to find out by lengthy bouts of experimentation, but the results have NOT changed since those days of long ago.
Leaner is Cooler and Leaner is Better!
I think Lynn is right on the true path to greater knowledge of how to properly, safely, and efficiently, operate his engine.
Make any sense at all?
Happy Skies,
Old Bob
In a message dated 8/25/2009 1:12:49 P.M. Central Daylight Time, noelloveys(at)yahoo.ca writes:
| Quote: |
Increasing throttle under load
So basically what I was saying was the same thing as Continental and Lycoming… Stay rich of peak when you need lots of power. Lean of Peak should be reserved basically for long descents at lower throttle settings, taxiing or possibly endurance flight.
When I was in flight school the school instructed me to always lean the engine LOP except for takeoff which we used full throttle for a lot of the training exercises that was ok but we cruised the C172 at close to 75% throttle. On solo flights I always ran ROP except if I was doing a long decent of say five minutes or more. Once in the landing circuit I always went full rich to be ready to draw power for a go around.
Most of the carbs are set up to run the engine a little rich at idle to make them easier to start. While warming up an engine or taxiing I usually mixed LOP. Part of the checklist turning onto the runway was to mix full rich… The field was on a plateau 400 ft msl.
A lot of the instructors and students didn’t use the same fuel management on the ground as I did and as far as I can see the paid for it fouled plugs. On one occasion I saw the plane I was about to fly pull up to the fuel pumps spewing a fair bit of soot from the exhaust. I called the AME ( Aircraft Maintenance Engineer) lean the idle mixture a bit. For a week the engine ran great but one student just couldn’t get it started after a cold night so they enrichened it again until we got warmer weather.
I’m not sure if the flight school wanted to keep me or kill me. Almost every flight I would find snags in the plane. Low tires, crud build up on the control hinges and spinner problems were all cleared in short order. That may have been why they always scheduled me to fly at daybreak… The plane wouldn’t see and engineer until my next flight. I also noticed the instructors would stick close to the other students during their walk around but in my case they only checked the fuel caps were in place….
Noel
From: owner-jabiruengine-list-server(at)matronics.com [mailto:owner-jabiruengine-list-server(at)matronics.com] On Behalf Of BobsV35B(at)aol.com
Sent: Tuesday, August 25, 2009 1:08 AM
To: jabiruengine-list(at)matronics.com
Subject: Re: ROP versus LOP...might be off-topic for some
Good Evening Noel,
Could you define what you mean by "pulling power".
Continental Motors generally suggests that lean side operations be restricted to sixty-five percent of maximum rated power. Lycoming generally uses a figure of seventy-five percent for the same purpose. Both manufacturers have a considerable number of restrictions as to when and how to run lean.
There are many text books that delve into lean side operations.
Curtiss Wright Corporation has given us about the most extensive guidance I have ever seen as to the "How Too's" of large radial engines.
Advanced Pilot Seminars of Ada, Oklahoma, teach a course of engine management which uses Continental, Lycoming and Curtiss Wright data to teach what really is happening at various power settings.
At very high power settings, (above sixty-five to seventy-five percent of maximum continuous horsepower)extra fuel is used by most aircraft engine manufacturers to move the peak cylinder pressures to a point where adequate cooling can be provided.
That data correlates well with data given by both Lycoming and Continental.
When does your training say that lean side operation is acceptable?
Happy Skies,
Old Bob
In a message dated 8/24/2009 10:18:24 P.M. Central Daylight Time, noelloveys(at)yahoo.ca writes:
| Quote: |
--> JabiruEngine-List message posted by: "Noel Loveys" <noelloveys(at)yahoo.ca>
Lynn:
For what it's worth my training told me that LOP is ok as long as you are
not drawing any power. If you are in a situation where power has to be
pulled you are better off at ROP. If you are constantly running LOP keep a
close eye on the top of your pistons.
Noel
-----Original Message-----
From: owner-jabiruengine-list-server(at)matronics.com
[mailto:owner-jabiruengine-list-server(at)matronics.com] On Behalf Of Lynn
Matteson
Sent: Saturday, August 15, 2009 3:45 PM
To: jabiruengines(at)yahoogroups.com; kitfox-list(at)matronics.com;
jabiruengine-list(at)matronics.com
Subject: ROP versus LOP...might be off-topic for some
--> JabiruEngine-List message posted by: Lynn Matteson <lynnmatt(at)jps.net>
Over the last week, I've had some fun making some tests with my newly-
installed Rotec TBI-40 mixture-adjustable, carburetor-replacement
device on my Jabiru engine. I don't know whether two of these units
will work on a Rotax, so many of you might want to hit the delete key
right now.
For the most part, I was flying it LOP (lean-of-peak), but yesterday
I made a flight and decided that I would try ROP (rich-of-peak). In
flying LOP, the articles I've read say to keep the power requirements
low, and LOP will work and you won't burn the engine down. I was
amazed that this LOP thing even works at all, let alone work as well
as I've found that it seems too....I guess I'm still a bit of a
skeptic. After all, if going lean is a bad thing, how can going even
leaner be a good thing? I won't argue whether or not it's a good or
bad thing, and there are those of you that may not be able to do any
leaning at all, as I was until I got this unit.
Three days ago, I made two trips totaling 475 miles, using LOP
settings, and yesterday I made a 310-mile trip, using ROP settings. I
had flown the 475 miles leaning out the engine until peak EGT, then
leaning more until the engine was obviously low on power, and I
contentedly flew at this setting, watching the scenery crawl by.
Yesterday I decided to actually GO somewhere, and never mind the fuel
saving, I just wanted to get there, so I decided to try ROP.
Here are the average numbers from those trips:
LOP: 27.77 miles per gallon; 3.3 gallons per hour; 93.14
miles per hour
ROP: 23.66 miles per gallon; 4.37 gallons per hour; 103.3 miles per
hour
Altitudes on all of these flight were anywhere from 3000' MSL (with a
base of 1000') to 10,000 MSL, with throttle settings from 2600 rpm to
3050. Fuel flow as seen on the gauge, ranged from 2.5 gallons per
hour to 5.0 not including takeoffs, but including climbs.
So you can see from these figures (admittedly a low number of
samples) that it does pay to tweak the mixture, and even if flown
LOP, the speed is not too bad.
Lynn Matteson
Kitfox IV Speedster, taildragger
Jabiru 2200, #2062, 737.3 hrs
Sensenich 62"x46" Wood prop
Electroair direct-fire ignition system
Rotec TBI-40 injection
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Lynn Matteson
Joined: 10 Jan 2006
Posts: 2778
Location: Grass Lake, Michigan
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| Posted: Tue Aug 25, 2009 4:57 pm Post subject: ROP versus LOP...might be off-topic for some |
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Right now I'm testing the benefits of having done some hogging out of
the inside of the intake manifold. I also made a nylon washer-like
device that filled the gap between the rubber coupling and the Jabiru
adapter snout (my terminology...they may have a better name for it)
that bolts to the intake manifold. This device also takes out the
"stepping" in diametrical differences between the TBI and the coupler
and the snout.
In looking through the intake manifold, I could see that the front
cylinders appeared to be starving for air flow, so I did a little
"porting" to allow them to breathe better. Initial flights show that
I didn't hurt performance any, but some more flying will tell if I
did any good. I can say that initially, at least, the cylinders all
seem to peak at the same time...same fuel flow (3.1 gph).....although
still not at the same EGT. And I understand that getting the same EGT
is not critical between cylinders. I need to run the GAMI Lean Test
again to be sure, but initially I think I've got the EGT's peaking
Here are some pictures I took during the hogging out operation. The
first shows the view through the stock intake manifold, rear to
front. The second shows that the lower half of the manifold has been
cut, taking out some of the web that I felt was interfering with the
air flow to cyls. number 1&2...the front ones. The last picture shows
the almost finished job. You can see that there is more of the front
openings (where the intake tubes are inserted) visible, and that the
air should flow around the splitter/divider better. The factory had
apparently done some tests with shaping the splitter, and found that
its shape was the best they could do. I was even thinking of making
the splitter sort of hour-glass shaped, but decided to leave well
enough alone for the present time. Gotta save some fun for another
day. : )
Lynn Matteson
Kitfox IV Speedster, taildragger
Jabiru 2200, #2062, 744.1 hrs
Sensenich 62"x46" Wood prop
Electroair direct-fire ignition system
Rotec TBI-40 injection
Status: flying
On Aug 25, 2009, at 4:10 PM, BobsV35B(at)aol.com wrote:
| Quote: |
Leaner is Cooler and Leaner is Better!
I think Lynn is right on the true path to greater knowledge of how
to properly, safely, and efficiently, operate his engine.
Make any sense at all?
Happy Skies,
Old Bob
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_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM |
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BobsV35B(at)aol.com
Guest
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| Posted: Tue Aug 25, 2009 6:53 pm Post subject: ROP versus LOP...might be off-topic for some |
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Good Evening Lynn,
You are doing great!
It is true that the actual EGT temperature is immaterial. All that counts is that all cylinders reach their peak EGT at the same fuel flow. One tenth of a gallon is probably as good at is going to get. Maximum power will be developed if each cylinder gets the same maximum amount of air. Sounds like you are doing what it might take to get the maximum amount of air into each cylinder.
Thanks for the update.
Happy Skies,
Old Bob
In a message dated 8/25/2009 7:58:00 P.M. Central Daylight Time, lynnmatt(at)jps.net writes:
| Quote: | Right now I'm testing the benefits of having done some hogging out of
the inside of the intake manifold. I also made a nylon washer-like
device that filled the gap between the rubber coupling and the Jabiru
adapter snout (my terminology...they may have a better name for it)
that bolts to the intake manifold. This device also takes out the
"stepping" in diametrical differences between the TBI and the coupler
and the snout.
In looking through the intake manifold, I could see that the front
cylinders appeared to be starving for air flow, so I did a little
"porting" to allow them to breathe better. Initial flights show that
I didn't hurt performance any, but some more flying will tell if I
did any good. I can say that initially, at least, the cylinders all
seem to peak at the same time...same fuel flow (3.1 gph).....although
still not at the same EGT. And I understand that getting the same EGT
is not critical between cylinders. I need to run the GAMI Lean Test
again to be sure, but initially I think I've got the EGT's peaking
Here are some pictures I took during the hogging out operation. The
first shows the view through the stock intake manifold, rear to
front. The second shows that the lower half of the manifold has been
cut, taking out some of the web that I felt was interfering with the
air flow to cyls. number 1&2...the front ones. The last picture shows
the almost finished job. You can see that there is more of the front
openings (where the intake tubes are inserted) visible, and that the
air should flow around the splitter/divider better. The factory had
apparently done some tests with shaping the splitter, and found that
its shape was the best they could do. I was even thinking of making
the splitter sort of hour-glass shaped, but decided to leave well
enough alone for the present time. Gotta save some fun for another
day. : )
Lynn Matteson
Kitfox IV Speedster, taildragger
Jabiru 2200, #2062, 744.1 hrs
Sensenich 62"x46" Wood prop
Electroair direct-fire ignition system
Rotec TBI-40 injection
Status: flying
On Aug 25, 2009, at 4:10 PM, BobsV35B(at)aol.com wrote:
| Quote: |
Leaner is Cooler and Leaner is Better!
I think Lynn is right on the true path to greater knowledge of how
to properly, safely, and efficiently, operate his engine.
Make any sense at all?
Happy Skies,
Old Bob
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Float Flyr
Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland
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| Posted: Fri Aug 28, 2009 1:52 pm Post subject: ROP versus LOP...might be off-topic for some |
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I’m in agreement with much of what you wrote. The 172 I trained in did cruise at above 75% power. So yes on long cruises I would lean the engine… I also leaned above six thousand feet. Our land here is basically all sea level except for the plateau where Gander International is located (400’). Most of our training was done at full rich mix. I think I was the only one who leaned for taxiing and warm up.
In my thinking the best method of leaning is to use EGTs, one on each cylinder. Electronic engine management systems are great but I’m a bit old school and like to be able to keep an eye on gauges. Case in point is my Subaru Imprezza. The darn check engine light came on last week… It turns out after reading the codes that I have a heater in my first air fuel ratio sensor burned out. That causes the car to run waaaay rich when cold but affects little else. Problem is Subaru in their folly neglected to install any instruments so if I had a second problem crop up I would have no way of detecting it. I’ve borrowed an analyzer which I lay on the seat beside me and once a trip I shut off the alert light. Darn expensive instrument set!
My pre flight instruction training was as an AME. Not the American one, the Canadian one, so to clear things up AME here is an Aircraft Maintenance Engineer. I have formal training in both piston and turbine engines and a couple of thousand hours operating them not to mention tearing them down and rebuilding them. I agree that the flight school, as far as I was concerned took every short cut in the book when it came to engine management. That was one of the reasons I was so critical of the plane before I would fly it. I’m just as glad I didn’t get the opportunity to do a 50 hr inspection on that plane…. It may still be grounded. J
Noel
From: owner-jabiruengine-list-server(at)matronics.com [mailto:owner-jabiruengine-list-server(at)matronics.com] On Behalf Of BobsV35B(at)aol.com
Sent: Tuesday, August 25, 2009 5:17 PM
To: jabiruengine-list(at)matronics.com
Subject: Re: ROP versus LOP...might be off-topic for some
Good Afternoon Noel,
Do you generally cruise above seventy-five percent power?
If so, ROP is probably best unless you have a supercharger. Whole 'nother question.
Do you ever cruise above six thousand feet MSL?
If you do (with a normally aspirated engine) there is no way you could damage the engine with the mixture control regardless of what you did with it!
Personally, I find that the vast majority of my flying is done at power settings where LOP is by FAR the better way to go.
Very few flight training operations have the time or the inclination to teach proper engine operations for any regime other than the basic training operation. It is also very rare that any training operation will have instrumentation installed that will tell the pilot whether or not the fuel distribution is good enough to allow Lean Side Operations.
Individual airplanes of the same model and same vintage often vary widely as to fuel distribution. There are methods that can be used to determine fuel balance, but it gets quite time consuming to do so. Without good distribution, you can't take advantage of the lean side.
However, once we do have good distribution and lean side operations ARE practical, the benefits are great.
That is the beauty of a course such as is available from the Advanced Pilot Seminar folks. It teaches us first how to find out how the airplane we are flying works. It then tells us how to fix it if something is wrong.
As Lynn has told us, he was fortunate enough to read most of what John Deakin has written on the subject.
There are a lot of Old Wives Tales that are taught beginning students because there is not adequate time in the training syllabus to completely cover the issue.
If you include normal cross country flight as your definition of endurance flight and you don't go cross country, I guess you have little use for Lean Side operation, but I cannot imagine operating in any other way.
It does take training. There is no quick "cookie cutter" formula to tell us how to do it, but the benefits in longer engine life, cooler operations, and cleaner engine operations are worth the effort all by themselves.
The lower fuel costs and greater range available are just icing on the cake.
I never flew a piston engine airliner that was NOT operated in some form of lean side operation. For the short haul airplanes, it was "Auto Lean'. For long haul, especially when we had the services of a flight engineer, it was manually leaned well beyond the point of Auto Lean.
We now have the benefit of excellent low cost engine instrumentation to tell us what Lindbergh had to find out by lengthy bouts of experimentation, but the results have NOT changed since those days of long ago.
Leaner is Cooler and Leaner is Better!
I think Lynn is right on the true path to greater knowledge of how to properly, safely, and efficiently, operate his engine.
Make any sense at all?
Happy Skies,
Old Bob
In a message dated 8/25/2009 1:12:49 P.M. Central Daylight Time, noelloveys(at)yahoo.ca writes:
[quote]
Increasing throttle under load
So basically what I was saying was the same thing as Continental and Lycoming… Stay rich of peak when you need lots of power. Lean of Peak should be reserved basically for long descents at lower throttle settings, taxiing or possibly endurance flight.
When I was in flight school the school instructed me to always lean the engine LOP except for takeoff which we used full throttle for a lot of the training exercises that was ok but we cruised the C172 at close to 75% throttle. On solo flights I always ran ROP except if I was doing a long decent of say five minutes or more. Once in the landing circuit I always went full rich to be ready to draw power for a go around.
Most of the carbs are set up to run the engine a little rich at idle to make them easier to start. While warming up an engine or taxiing I usually mixed LOP. Part of the checklist turning onto the runway was to mix full rich… The field was on a plateau 400 ft msl.
A lot of the instructors and students didn’t use the same fuel management on the ground as I did and as far as I can see the paid for it fouled plugs. On one occasion I saw the plane I was about to fly pull up to the fuel pumps spewing a fair bit of soot from the exhaust. I called the AME ( Aircraft Maintenance Engineer) lean the idle mixture a bit. For a week the engine ran great but one student just couldn’t get it started after a cold night so they enrichened it again until we got warmer weather.
I’m not sure if the flight school wanted to keep me or kill me. Almost every flight I would find snags in the plane. Low tires, crud build up on the control hinges and spinner problems were all cleared in short order. That may have been why they always scheduled me to fly at daybreak… The plane wouldn’t see and engineer until my next flight. I also noticed the instructors would stick close to the other students during their walk around but in my case they only checked the fuel caps were in place….
Noel
From: owner-jabiruengine-list-server(at)matronics.com [mailto:owner-jabiruengine-list-server(at)matronics.com] On Behalf Of BobsV35B(at)aol.com
Sent: Tuesday, August 25, 2009 1:08 AM
To: jabiruengine-list(at)matronics.com
Subject: Re: ROP versus LOP...might be off-topic for some
Good Evening Noel,
Could you define what you mean by "pulling power".
Continental Motors generally suggests that lean side operations be restricted to sixty-five percent of maximum rated power. Lycoming generally uses a figure of seventy-five percent for the same purpose. Both manufacturers have a considerable number of restrictions as to when and how to run lean.
There are many text books that delve into lean side operations.
Curtiss Wright Corporation has given us about the most extensive guidance I have ever seen as to the "How Too's" of large radial engines.
Advanced Pilot Seminars of Ada, Oklahoma, teach a course of engine management which uses Continental, Lycoming and Curtiss Wright data to teach what really is happening at various power settings.
At very high power settings, (above sixty-five to seventy-five percent of maximum continuous horsepower)extra fuel is used by most aircraft engine manufacturers to move the peak cylinder pressures to a point where adequate cooling can be provided.
That data correlates well with data given by both Lycoming and Continental.
When does your training say that lean side operation is acceptable?
Happy Skies,
Old Bob
In a message dated 8/24/2009 10:18:24 P.M. Central Daylight Time, noelloveys(at)yahoo.ca writes:
[quote]
--> JabiruEngine-List message posted by: "Noel Loveys" <noelloveys(at)yahoo.ca>
Lynn:
For what it's worth my training told me that LOP is ok as long as you are
not drawing any power. If you are in a situation where power has to be
pulled you are better off at ROP. If you are constantly running LOP keep a
close eye on the top of your pistons.
Noel
--
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Noel Loveys
Kitfox III-A
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