---------------------------------------------------------- JabiruEngine-List Digest Archive --- Total Messages Posted Mon 08/24/09: 2 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 08:17 PM - Re: ROP versus LOP...might be off-topic for some (Noel Loveys) 2. 08:38 PM - Re: ROP versus LOP...might be off-topic for some (BobsV35B@aol.com) ________________________________ Message 1 _____________________________________ Time: 08:17:50 PM PST US From: "Noel Loveys" Subject: RE: JabiruEngine-List: ROP versus LOP...might be off-topic for some 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@matronics.com [mailto:owner-jabiruengine-list-server@matronics.com] On Behalf Of Lynn Matteson Sent: Saturday, August 15, 2009 3:45 PM jabiruengine-list@matronics.com Subject: JabiruEngine-List: 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 ________________________________ Message 2 _____________________________________ Time: 08:38:46 PM PST US From: BobsV35B@aol.com Subject: Re: JabiruEngine-List: 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@yahoo.ca writes: --> JabiruEngine-List message posted by: "Noel Loveys" 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@matronics.com [mailto:owner-jabiruengine-list-server@matronics.com] On Behalf Of Lynn Matteson Sent: Saturday, August 15, 2009 3:45 PM jabiruengine-list@matronics.com Subject: JabiruEngine-List: ROP versus LOP...might be off-topic for some --> JabiruEngine-List message posted by: Lynn Matteson 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 ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message jabiruengine-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/JabiruEngine-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/jabiruengine-list Browse Digests http://www.matronics.com/digest/jabiruengine-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.