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Lynn Matteson

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

Posted: Sat Aug 15, 2009 10:21 am Post subject: ROP versus LOP...might be off-topic for some

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: flying

_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

Tom Jones

Joined: 12 Mar 2006
Posts: 752
Location: Ellensburg, WA

Posted: Sat Aug 15, 2009 2:10 pm Post subject: Re: ROP versus LOP...might be off-topic for some

Lynn, being that I am a two stroke guy the word lean gets my attention right away.  I guess it is different for 4 stroke engines.



I learned to fly in a Cherokee 180.  The instructions for best economy in the POH for that airplane were.  Lean until max EGT is reached then continue to lean until EGT drops a minimum of 25 degrees.  It also said do not lean the engine when running above 75% power.



For best power the instructions are to lean until maximum EGT is reached then richen until EGT decreases 25 degrees.



It is interesting for me so I enjoy reading your posts on this stuff.  You will be able to write the POH for your engine with all the information you are collecting.



edited to change increases to decreases in the best power sentence. tj

_________________
Tom Jones
Classic IV
503 Rotax, 72 inch Two blade Warp
Ellensburg, WA

Last edited by Tom Jones on Sat Aug 15, 2009 4:28 pm; edited 1 time in total

Lynn Matteson

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

Posted: Sat Aug 15, 2009 4:10 pm Post subject: ROP versus LOP...might be off-topic for some

Tom, this is all very new to me, and so it surprises me that the  

instructions for a 180 include leaning beyond the max EGT. I only  

began hearing about this "black magic" about a month ago. During  

recent searches on the subject, I found that it's been discussed for  

five years or more. (I must have taken a really long nap!) I always  

like to find new information about things that were seemingly cast in  

stone, and not to be tried.



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: flying

On Aug 15, 2009, at 6:10 PM, Tom Jones wrote:



 	  Quote: 	
		   



 Lynn, being that I am a two stroke guy the word lean gets my  

 attention right away.  I guess it is different for 4 stroke engines.



 I learned to fly in a Cherokee 180.  The instructions for best  

 economy in the POH for that airplane were.  Lean until max EGT is  

 reached then continue to lean until EGT drops a minimum of 25  

 degrees.  It also said do not lean the engine when running above  

 75% power.



 For best power the instructions are to lean until maximum EGT is  

 reached then richen until EGT increases 25 degrees.



 It is interesting for me so I enjoy reading your posts on this  

 stuff.  You will be able to write the POH for your engine with all  

 the information you are collecting.



 --------

 Tom Jones

 Classic IV

 503 Rotax, 72 inch Two blade Warp

 Ellensburg, WA





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p 57868#257868

_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

Fox5flyer
Guest

Posted: Sat Aug 15, 2009 5:06 pm Post subject: ROP versus LOP...might be off-topic for some

Lynn, I've been leaning LOP on my EA81 with Ellison TB for more than the 

past 300 hours.  It's actually been done for much longer than 5 years.  I 

spoke with a friend who flew B25s and he said it was routine operation. 

Like you said, you lose a small amount of power, but the fuel savings payoff 

is worth it.  The caveat here is that one needs to have a good display of 

the cylinder EGTs and to not do it with high manifold pressures.

Good report you gave on the topic.  Thanks.

Below is the article written by John Deacon on the subject.  Lengthy, but 

enlightening.

http://www.avweb.com/news/pelican/182084-1.html

Deke Morisse

Mikado Michigan

S5/Subaru/CAP 430+ TT

"The aim of an argument or discussion should not be victory, but progress."

- Joseph Joubert

---

MichaelGibbs(at)cox.net
Guest

Posted: Sun Aug 16, 2009 1:23 am Post subject: ROP versus LOP...might be off-topic for some

Lynn,



Aviation is loaded with myth and wives tales about LOP operations. 

If you'd like to learn the straight scoop from some folks that have 

been studying the issue intensely for years now, check out 

<http://www.gami.com/>, particularly the articles 

<http://www.gami.com/articles/articles.php>.



These guys have reams of data from some of the most 

heavily-instrumented engines on the planet and they are firm 

believers in LOP operation.



Mike G.

Kitfox IV-1200 Speedster

Phoenix, AZ

Lynn Matteson

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

Posted: Sun Aug 16, 2009 2:23 am Post subject: ROP versus LOP...might be off-topic for some

Thanks for the links, Mike...and speaking of "reams", I just went to  

the Deakin article that Deke mentioned, and it's gonna take a ream of  

paper to print THAT one, but I will.

In fact, it was a local lady pilot that was telling me about the GAMI  

folks and how she had just got done running some LOP tests in her  

CH801. When she told me about leaning beyond peak EGT, and the temps  

went DOWN, I was shocked. First off, that a woman would know about  

this "magic" before I did, and second, that it would work at all.  

Sorry about being sexist, ladies, but I guess old habits die hard.



Damn, I really DID spend too much time as a photographer, and let my  

motor skills snooze.



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: flying

do not archive



On Aug 16, 2009, at 4:59 AM, Michael Gibbs wrote:



 	  Quote: 	
		   

 <MichaelGibbs(at)cox.net>



 Lynn,



 Aviation is loaded with myth and wives tales about LOP operations.  

 If you'd like to learn the straight scoop from some folks that have  

 been studying the issue intensely for years now, check out <http:// 

 www.gami.com/>, particularly the articles <http://www.gami.com/ 

 articles/articles.php>.



 These guys have reams of data from some of the most heavily- 

 instrumented engines on the planet and they are firm believers in  

 LOP operation.



 Mike G.

 Kitfox IV-1200 Speedster

 Phoenix, AZ

_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

Paul A. Franz, P.E.

Joined: 02 Dec 2008
Posts: 280
Location: Bellevue WA

Posted: Sun Aug 16, 2009 3:57 am Post subject: ROP versus LOP...might be off-topic for some

On Sun, August 16, 2009 1:59 am, Michael Gibbs wrote:

 	  Quote: 	
		   


	


 	  Quote: 	
		   Aviation is loaded with myth and wives tales about LOP operations.

 If you'd like to learn the straight scoop from some folks that have

 been studying the issue intensely for years now, check out

 <http://www.gami.com/>, particularly the articles

 <http://www.gami.com/articles/articles.php>.


	


Mikel,



You've found an excellent and very interesting collection of articles. In this one:



<http://www.gami.com/articles/frugalflyer.php>



They say:



Not all GA engines can run safely LOP. Carbureted engines, for example, lack precise

fuel/air metering systems and typically run rough and lose power LOP. And electronic

engine monitors that show cylinder head and exhaust gas temperatures for every

cylinder are necessary for safe LOP operations. Graphic engine monitors are even

better.



The danger of flying LOP with a single-cylinder CHT or EGT probe is that some

rich-running cylinders could become too hot, damaging internal valves and guides, and

causing a loss of engine compression that would require a top overhaul.



“The problem isn’t running too lean,” Braly said. “The problem is running too rich

without knowing about it.”



Bill Middlebrook, president of Penn Yan Aero, a New York company that performs about

400 engine overhauls annually, said properly equipped engines are operating lean of

peak safely and reliably. But carbureted engines, and those without engine monitors,

can and are being damaged from pilots running them too lean. “We’ve never had any

issues with lean-of-peak operations in engines equipped with GAMI injectors and

graphic engine monitors,” Middlebrook said. “In fact, we’ve got them on our own

aircraft fleet. But we’re also seeing burned valves and cylinder damage in carbureted

engines or those with single-point EGTs trying to fly lean of peak. If you don’t have

matched fuel injection nozzles and a six-point engine monitor, you just don’t have

enough information for lean-of-peak operations.”

-- 

Paul A. Franz

Registration/Aircraft - N14UW/Merlin GT

Engine/Prop - Rotax 914/NSI CAP

Bellevue WA

425.241.1618 Cell



"The collection of taxes which are not absolutely required, which

do not beyond reasonable doubt contribute to the public welfare, is

only a species of legalized larceny. The wise and correct course to

follow in taxation is not to destroy those who have already secured

success, but to create conditions under which everyone will have a

better chance to be successful."

-- President Calvin Coolidge (1873-1933)



It's passionately interesting for me that the things that I learned in a

small town, in a very modest home, are just the things that I believe

have won the election.

-- Margaret Thatcher



Take time to deliberate; but when the time for action arrives, stop

thinking and go in.

-- Andrew Jackson



"We have rights, as individuals, to give as much of our own money as

we please to charity; but as members of Congress we have no right so

to appropriate a dollar of public money."

-- American hunter, frontiersman, soldier and politician Davy Crockett (1786-1836)



"Would it not be better to simplify the system of taxation rather

than to spread it over such a variety of subjects and pass through

so many new hands."

--Thomas Jefferson, letter to James Madison, 1784

_________________
Paul A. Franz, P.E.
Registration/Aircraft - N14UW/Merlin GT
Engine/Prop - Rotax 914/NSI CAP
Bellevue WA
425.241.1618 Cell
425.440.9505 Office

MichaelGibbs(at)cox.net
Guest

Posted: Sun Aug 16, 2009 9:15 pm Post subject: ROP versus LOP...might be off-topic for some

 	  Quote: 	
		  Mikel,

You've found an excellent and very interesting collection of articles.


	


My partners and I have GAMInjectors on our Turbo Arrow III, that's 

how I became aware of their company and web site.



Mike G.

Kitfox IV-1200 Speedster

Phoenix, AZ

Lynn Matteson

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

Posted: Mon Aug 17, 2009 9:46 am Post subject: ROP versus LOP...might be off-topic for some

I know what you mean, Tom....lean to you means less oil to lube the  

bottom end, eh? Unless things have changed since I last ran a 2- 

stroke, all the bottom end stuff gets lubed via the oil, right? Or is  

that what the oil injected engines do, is take care of the lubing so  

the fuel can go oil-less?



Lynn Matteson

Kitfox IV Speedster, taildragger

Jabiru 2200, #2062, 739.7 hrs

Sensenich 62"x46" Wood prop

Electroair direct-fire ignition system

Rotec TBI-40 injection

Status: flying

do not archive



On Aug 15, 2009, at 6:10 PM, Tom Jones wrote:



 	  Quote: 	
		   



 Lynn, being that I am a two stroke guy the word lean gets my  

 attention right away.  I guess it is different for 4 stroke engines.



 I learned to fly in a Cherokee 180.  The instructions for best  

 economy in the POH for that airplane were.  Lean until max EGT is  

 reached then continue to lean until EGT drops a minimum of 25  

 degrees.  It also said do not lean the engine when running above  

 75% power.



 For best power the instructions are to lean until maximum EGT is  

 reached then richen until EGT increases 25 degrees.



 It is interesting for me so I enjoy reading your posts on this  

 stuff.  You will be able to write the POH for your engine with all  

 the information you are collecting.



 --------

 Tom Jones

 Classic IV

 503 Rotax, 72 inch Two blade Warp

 Ellensburg, WA





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p 57868#257868

_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

Tom Jones

Joined: 12 Mar 2006
Posts: 752
Location: Ellensburg, WA

Posted: Mon Aug 17, 2009 11:17 am Post subject: Re: ROP versus LOP...might be off-topic for some

 	  Quote: 	
		  I know what you mean, Tom....lean to you means less oil to lube the

bottom end, eh? Unless things have changed since I last ran a 2-

stroke, all the bottom end stuff gets lubed via the oil, right? Or is

that what the oil injected engines do, is take care of the lubing so

the fuel can go oil-less? 	




Lynn, pretty much what you say about the lube is correct.  The top end...piston skirts and wrist pins/bearings...are also lubed with the two stroke oil.  Premixed or injected the oil serves the same purpose.



The fuel also cools the top of the pistons.  A lean fuel/air mixture can burn a hole in the top of the pistons or melt the outside of the top of the piston around the rings and cause the pistons to seize to the cylinder walls.



The good book of Rotax says "Thou shalt not exceed EGT of 1200 degrees F in Thy two stroke engine".

_________________
Tom Jones
Classic IV
503 Rotax, 72 inch Two blade Warp
Ellensburg, WA

mhubel

Joined: 05 Sep 2009
Posts: 141

Posted: Sun Sep 06, 2009 5:30 pm Post subject: Rotac TBI 40 installation details-

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



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



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

_________________
Mark Hubelbank
N708HU
CH601XL
Jabiru 3300
Rotec TBI 40-3 carb
Sensenich ground adj prop.
240 hr TAF
Pictures at photo.hubbles.com

Lynn Matteson

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

Posted: Sun Sep 06, 2009 7:09 pm Post subject: ROP versus LOP...might be off-topic for some

After about three weeks of using the TBI without hooking up a control  

cable to the primer button, I finally did it and it works great. Here  

are some pictures of how I made a small bellcrank to actuate my  

button, and of the bellcrank that I built that transferred throttle  

cable motion from one side of the TBI to the other side and increase  

the throw of the throttle to provide better  control/easier  

operation. The orange bellcrank also shows the bracket that allows  

for attachment of the throttle cable and for the mixture control  

cable. Regarding the primer control, I was kinda cramped for room in  

the engine compartment, so the mechanical "advantage" of the leverage  

is a non-advantage. The picture doesn't show the cable attachment,  

but it is too close for proper operation, meaning that it takes a lot  

of puling power on the cable to get the button depressed, but it does  

work. I'm going to rework it to provide a better mechanical  

advantage. And yes, the cable goes into the cabin right alongside the  

mixture control and throttle cables.



  Here is a picture of the main bellcrank/cable attachment device  

that I built....the orange device (in case the captions get mixed  

up). You can see the brackets that I welded on where the mixture (top  

hole with slot), and throttle (bottom hole with slot) control cables  

go.  I built this up out of aluminum, and TIG-welded the assembly  

together...steel could also be used, of course. Because I wanted to  

retain the original throttle cable, and because I wanted to increase  

the travel of the throttle for better control of rpm, I made the arms  

long and short accordingly. I used the former "choke" cable to the  

original Bing carb for the mixture control cable...painting the knob  

red, of course.





I sent this picture to Rotec, per their request, so as to maybe give  

Jabiru owners another way to make the connections, but apparently  

they haven't posted it yet. This required bending of the end of the  

throttle slide-actuating attachment, but it was an easy bend, and  

this mechanism works perfectly.





And here is the primer button-actuating bellcrank. If I can do a  

little "massaging" of the firewall footwell area, I'll be able to  

lengthen the upper part of the bellcrank, and that will make for an  

easier pull on the cable. Right now the cable only moves about a half- 

inch, and requires a bit of a pull.



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



 	  Quote: 	
		   



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

 Zenith CH601XL.



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

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

 what sort of assembly was used?



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

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

 the ROTAC web site.



 --------

 Mark Hubelbank

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_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

mhubel

Joined: 05 Sep 2009
Posts: 141

Posted: Sun Sep 06, 2009 7:23 pm Post subject: Re: ROP versus LOP...might be off-topic for some

Thanks, If I go in this direction, now I know what to expect. I am a bit surprised that Rotec does not offer the option of some pre made assemblies to mount the mixture and primer cables.

_________________
Mark Hubelbank
N708HU
CH601XL
Jabiru 3300
Rotec TBI 40-3 carb
Sensenich ground adj prop.
240 hr TAF
Pictures at photo.hubbles.com

Lynn Matteson

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

Posted: Mon Sep 07, 2009 2:19 am Post subject: ROP versus LOP...might be off-topic for some

I'm thinking that this TBI is a bit new to them, and it might just be  

that later on they will. Apparently they don't even offer the intake  

flange, either. Although Paul, their rep at Oshkosh, said that they  

have done major testing on their engine and on Jabiru's , and that  

shows that they've had it for some time.



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 6, 2009, at 11:23 PM, mhubel wrote:



 	  Quote: 	
		   



 Thanks, If I go in this direction, now I know what to expect. I am  

 a bit surprised that Rotec does not offer the option of some pre  

 made assemblies to mount the mixture and primer cables.



 --------

 Mark Hubelbank





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p 61811#261811

_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

Lynn Matteson

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

Posted: Mon Sep 07, 2009 3:04 am Post subject: ROP versus LOP...might be off-topic for some

After about three weeks of using the TBI without hooking up a control  

cable to the primer button, I finally did it and it works great. Here  

are some pictures of how I made a small bellcrank to actuate my  

button, and of the bellcrank that I built that transferred throttle  

cable motion from one side of the TBI to the other side and increase  

the throw of the throttle to provide better  control/easier  

operation. The orange bellcrank also shows the bracket that allows  

for attachment of the throttle cable and for the mixture control  

cable. Regarding the primer control, I was kinda cramped for room in  

the engine compartment, so the mechanical "advantage" of the leverage  

is a non-advantage. The picture doesn't show the cable attachment,  

but it is too close for proper operation, meaning that it takes a lot  

of puling power on the cable to get the button depressed, but it does  

work. I'm going to rework it to provide a better mechanical  

advantage. And yes, the cable goes into the cabin right alongside the  

mixture control and throttle cables.



  Here is a picture of the main bellcrank/cable attachment device  

that I built....the orange device (in case the captions get mixed  

up). You can see the brackets that I welded on where the mixture (top  

hole with slot), and throttle (bottom hole with slot) control cables  

go.  I built this up out of aluminum, and TIG-welded the assembly  

together...steel could also be used, of course. Because I wanted to  

retain the original throttle cable, and because I wanted to increase  

the travel of the throttle for better control of rpm, I made the arms  

long and short accordingly. I used the former "choke" cable to the  

original Bing carb for the mixture control cable...painting the knob  

red, of course.





I sent this picture to Rotec, per their request, so as to maybe give  

Jabiru owners another way to make the connections, but apparently  

they haven't posted it yet. This required bending of the end of the  

throttle slide-actuating attachment, but it was an easy bend, and  

this mechanism works perfectly.





And here is the primer button-actuating bellcrank. If I can do a  

little "massaging" of the firewall footwell area, I'll be able to  

lengthen the upper part of the bellcrank, and that will make for an  

easier pull on the cable. Right now the cable only moves about a half- 

inch, and requires a bit of a pull.



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



 	  Quote: 	
		   



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

 Zenith CH601XL.



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

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

 what sort of assembly was used?



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

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

 the ROTAC web site.



 --------

 Mark Hubelbank

100_0407.jpg

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157.09 KB

Viewed:

10023 Time(s)

100_0448.jpg

Description:

Filesize:

90.06 KB

Viewed:

10023 Time(s)

_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

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