Engine Management Course
Join Date: Jul 2010
Location: rangaville
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No future in that mate 
It's fairly long, I've been told to make sure you do it before the course
When you say you were @ 18 inches & 2500 RPM, peak EGT with 400f CHT, was that leaned as per Lycoming's leaning procedure & what is that procedure out of interest?
It's fairly long, I've been told to make sure you do it before the course
When you say you were @ 18 inches & 2500 RPM, peak EGT with 400f CHT, was that leaned as per Lycoming's leaning procedure & what is that procedure out of interest?
Hmm p*ssing contest aside....
I did APS with WA & GB in Sydney a few years ago. Well worth it and recommend it to anyone.
Even got a dinner out "on the town" with those guys. Great blokes making for a top seminar.
Enjoy !
I did APS with WA & GB in Sydney a few years ago. Well worth it and recommend it to anyone.
Even got a dinner out "on the town" with those guys. Great blokes making for a top seminar.
Enjoy !
Join Date: Jul 2005
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Jack
The engine is a Continental io520 and the Flight Manual states that below 65% it's ok to operate at peak EGT. According to the performance tables in the Flight Manual I was at about 55% power. I achieve peak EGT by leaning to well below where I think it will be and then slowly in small steps increase the mixture while watching the EGT rise. When it stops rising and starts to decrease I bring it back to the position where it was highest and leave it there. At that setting I use 46 L per hour and TAS 162 knots.
I did not get those figures until I installed wingtip tanks which increased my wing area and greatly improved altitude performance. We won't talk about below 4000
Cheers RA
The engine is a Continental io520 and the Flight Manual states that below 65% it's ok to operate at peak EGT. According to the performance tables in the Flight Manual I was at about 55% power. I achieve peak EGT by leaning to well below where I think it will be and then slowly in small steps increase the mixture while watching the EGT rise. When it stops rising and starts to decrease I bring it back to the position where it was highest and leave it there. At that setting I use 46 L per hour and TAS 162 knots.
I did not get those figures until I installed wingtip tanks which increased my wing area and greatly improved altitude performance. We won't talk about below 4000
Cheers RA
Join Date: Apr 2013
Location: Vail, Colorado, USA
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Jack:
Having been involved in the design of an EMS, the cold junction is in the instrument, not at the probe. That means the cold junction is generally close to "room temperature" and fairly consistent. The reading is, therefore, pretty accurate. I also hand made probes for a radial engine. We simply drilled out #6 bolts, placed the wires inside and used ceramic paste to bond them. Since the cold joint is in the instrument, no other action was required.
These probes are pretty accurate--IMO, certainly within the tolerances needed to be operationally accurate.
Looking forward to meeting you.
Having been involved in the design of an EMS, the cold junction is in the instrument, not at the probe. That means the cold junction is generally close to "room temperature" and fairly consistent. The reading is, therefore, pretty accurate. I also hand made probes for a radial engine. We simply drilled out #6 bolts, placed the wires inside and used ceramic paste to bond them. Since the cold joint is in the instrument, no other action was required.
These probes are pretty accurate--IMO, certainly within the tolerances needed to be operationally accurate.
Looking forward to meeting you.
The probes are accurate. Its all about the instrument. Not many aircraft temperature gauges use cold junction compensation. But it doesn't necessarily matter a lot. 40 deg out of 1500 is not a big percentage and we were interested in trends and relative temperatures more than absolute temperatures.
Regarding engine break-in. I still reckon Phil Irving's book is among the best. I think it is still in print as the ACL engine manual. Unless you want to go to the oracle and read Sir Harry Ricardo's book " the high speed internal combustion engine" but I think its out of print.
Basically, you are trying to do 2 things: 1) knock the rough spots off rotating components (ie bearings) 2) bed the rings. There are some guys who talk about hardening the bearings, but that seems to mainly be the drag guys.
Its off topic, but the drag guys are interesting. They don't use much instrumentation because they pull the engine down after each race and inspect it.
The bearings want varying speed and light loads. The rings want high BMEP which peaks at the max torque rpm. In cars, you look for the biggest hill you can and do wide open throttle acceleration runs up it. You can't do that with aeroplanes, so 75% power settings are used instead. Constant power is also nicer on the pots which are probably less dimensionally stable than we'd like to know. The improved tolerances & quality of bearings now means that they don't really need running in. So its mainly about bedding in the rings.
Phil Irving maintains that you should have high idle speeds on new engines to aid splash lubrication.
The early oil change was originally to flush out the left over lint, gasket goo and assembly gunk. These days its not so necessary because its all so much better. The guys I know in oil companies say you can't change oil too often. The guys I know in filter companies say we change oil filters just when they start to work properly.
Basically, you are trying to do 2 things: 1) knock the rough spots off rotating components (ie bearings) 2) bed the rings. There are some guys who talk about hardening the bearings, but that seems to mainly be the drag guys.
Its off topic, but the drag guys are interesting. They don't use much instrumentation because they pull the engine down after each race and inspect it.
The bearings want varying speed and light loads. The rings want high BMEP which peaks at the max torque rpm. In cars, you look for the biggest hill you can and do wide open throttle acceleration runs up it. You can't do that with aeroplanes, so 75% power settings are used instead. Constant power is also nicer on the pots which are probably less dimensionally stable than we'd like to know. The improved tolerances & quality of bearings now means that they don't really need running in. So its mainly about bedding in the rings.
Phil Irving maintains that you should have high idle speeds on new engines to aid splash lubrication.
The early oil change was originally to flush out the left over lint, gasket goo and assembly gunk. These days its not so necessary because its all so much better. The guys I know in oil companies say you can't change oil too often. The guys I know in filter companies say we change oil filters just when they start to work properly.
Join Date: Apr 2013
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**Phil Irving maintains that you should have high idle speeds on new engines to aid splash lubrication.**
The splash inside the engine even at normal idle is amazingly good at putting liquid oil on the underside of the pistons and the cylinder walls. As the RPM increases the oil becomes a mist in the entire bottom end. Very little "liquid" larger than tiny mist-droplets is found out of the pan.
**The early oil change was originally to flush out the left over lint, gasket goo and assembly gunk. These days its not so necessary because its all so much better.**
Correct as far as that goes and is true in close tolerance auto engines. The tolerances of the aviation engines are such that a lot of small metal is generated and it never hurts to get that out of the circulating oil.
**The guys I know in oil companies say you can't change oil too often. The guys I know in filter companies say we change oil filters just when they start to work properly.**
True and sort of true. The problem with aircraft filters is that they tend to go into bypass and stop filtering after 15-20 hours. Some say it takes a bit longer. While they are correct that as a filter clogs, it filters better, but it's only true if it does not go into bypass.
The problem with oil discussions is that it's a science with a significant degree of black art remaining!
The splash inside the engine even at normal idle is amazingly good at putting liquid oil on the underside of the pistons and the cylinder walls. As the RPM increases the oil becomes a mist in the entire bottom end. Very little "liquid" larger than tiny mist-droplets is found out of the pan.
**The early oil change was originally to flush out the left over lint, gasket goo and assembly gunk. These days its not so necessary because its all so much better.**
Correct as far as that goes and is true in close tolerance auto engines. The tolerances of the aviation engines are such that a lot of small metal is generated and it never hurts to get that out of the circulating oil.
**The guys I know in oil companies say you can't change oil too often. The guys I know in filter companies say we change oil filters just when they start to work properly.**
True and sort of true. The problem with aircraft filters is that they tend to go into bypass and stop filtering after 15-20 hours. Some say it takes a bit longer. While they are correct that as a filter clogs, it filters better, but it's only true if it does not go into bypass.
The problem with oil discussions is that it's a science with a significant degree of black art remaining!
Join Date: Jul 2007
Location: in the classroom of life
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The upcoming APS classes in Melbourne and Brisbane will be an excellent opportunity to meet Walter and John as well as learn how to save yourself a fortune in maintenance costs. This is mainly by shortening up the fault finding process or in some cases predicting upcoming maintenance issues before they become a problem or one away from home.
There are many things discussed in the course that are potentially life saving, and in my opinion every private and commercial pilot with a piston engine should do this course. The return on investment is the best you will find anywhere. You owe it to your family and your wallet.
Advanced Pilot
There are many things discussed in the course that are potentially life saving, and in my opinion every private and commercial pilot with a piston engine should do this course. The return on investment is the best you will find anywhere. You owe it to your family and your wallet.
Advanced Pilot
I'd rely on the Lycoming Engineers rather than anyone else.
And I will go with Deakin (and the earlier editions of the Lycoming manuals) about running lean of peak. The engines haven't changed, but what has changed is that the lawyers have been writing (figuratively speaking) the later editions, not engineers/pilots who understand engines.
Tootle pip!!
Last edited by LeadSled; 8th Apr 2013 at 02:02.
Agree with Leadsled. The POH today is a marvel for what it does NOT contain, for example, no specific procedure for landing a C172 let alone any warning about what happens when you don't adhere to the unwritten part of the manual ---because that would be an admission by the manufacturer that the aircraft was less than perfect - leading to lawsuits over landing accidents.
To put that another way,: if American legal processes are allowed to continue to their logical conclusion the Pilots Operating Handbook will one day be reduced to one page and one phrase: "Contains nuts."
To put that another way,: if American legal processes are allowed to continue to their logical conclusion the Pilots Operating Handbook will one day be reduced to one page and one phrase: "Contains nuts."
Last edited by Sunfish; 7th Apr 2013 at 21:06.
As usual, I see it’s the lawyers’ fault!
If you’d actually read any of John Deakin’s articles (I have no idea who “Deacon” is), you’d know that the primary impediment to running LOP is the quality of stock manufactured engines. They rarely have induction/injection systems that result in all cylinders reaching peak on the lean curve at the same point during the leaning process. That means they ‘run rough’ (which is PR department-speak for “vibration due to different cylinders putting out different power”) nearing the lean end of the lean curve.
When lawyers build engines, they do it properly. Ask George Braly.
If you’d actually read any of John Deakin’s articles (I have no idea who “Deacon” is), you’d know that the primary impediment to running LOP is the quality of stock manufactured engines. They rarely have induction/injection systems that result in all cylinders reaching peak on the lean curve at the same point during the leaning process. That means they ‘run rough’ (which is PR department-speak for “vibration due to different cylinders putting out different power”) nearing the lean end of the lean curve.
When lawyers build engines, they do it properly. Ask George Braly.
Last edited by Creampuff; 8th Apr 2013 at 08:32. Reason: Added "is" before "PR"
The best article I've seen which explains this is by Ratcliffe & Rogers from the US Navy. "Balanced FUEL Injector Effects on Inflight Engine Vibration".
This article really says that balanced injectors are a bit of a band-aid to cover some really bad inlet manifold design. The bit I don't understand is why no-one has had a go at making tuned inlet runners. The Lycoming TSIO540 in the current Stationair is a pretty nice setup and seems to embody many elements of best practice. The inlets on our TSIO 360 are a disaster and are probably only saved by being force fed air.
Apart from the regulatory hoops, it would be easy to make something like that. I would expect that even just doubling the diameter of the longitudinal pipe which acts as a plenum chamber would help. I don't know why no-one has ever tried it.
This article really says that balanced injectors are a bit of a band-aid to cover some really bad inlet manifold design. The bit I don't understand is why no-one has had a go at making tuned inlet runners. The Lycoming TSIO540 in the current Stationair is a pretty nice setup and seems to embody many elements of best practice. The inlets on our TSIO 360 are a disaster and are probably only saved by being force fed air.
Apart from the regulatory hoops, it would be easy to make something like that. I would expect that even just doubling the diameter of the longitudinal pipe which acts as a plenum chamber would help. I don't know why no-one has ever tried it.
Creamie,
Apologies to John Deakin, I blame it on a late and very cold night after a long day here in Beijing.
As one poster has noted, forced induction does not solve the problem of lousy intake design, a most famous example was the Merlin 1, which was a hopeless engine until the supercharger and associated ducting was redesigned by Edwards, which increased the reliable power output from about 750 HP (each engine varied) to close the initial designed 1100 HP.
Tootle pip!!
Apologies to John Deakin, I blame it on a late and very cold night after a long day here in Beijing.
As one poster has noted, forced induction does not solve the problem of lousy intake design, a most famous example was the Merlin 1, which was a hopeless engine until the supercharger and associated ducting was redesigned by Edwards, which increased the reliable power output from about 750 HP (each engine varied) to close the initial designed 1100 HP.
Tootle pip!!
Old Akro,
I'm not doing well, am I, I think you are correct, it is all detailed in the book "Not Much Of An Engineer", have I got that much right.
But you won't find much about it in the official RR histories.
This weather must be freezing my brain.
Tootle pip!!
I'm not doing well, am I, I think you are correct, it is all detailed in the book "Not Much Of An Engineer", have I got that much right.
But you won't find much about it in the official RR histories.
This weather must be freezing my brain.
Tootle pip!!
If my memory is right - Sir Stanley was a mathematician and not an engineer and primarily made the improvements to the Merlin from first principals and analysis of airflow. His book is a great read.
The hallmark text for intake systems is still "Scientific Design of Intake & Exhaust Systems" by Smith & Morrisson. Its been years and years since I have read it. I would have thought the optimal intake runner length on an engine like our TSIO 360 would be twice as long or more than they are standard. In cars the intake length is frequently compromised by bonnets, etc. Its why you often see intake runners that curve on top of the engine. But, I suspect you could double the length of the intake runners on most Continental engines without much difficulty. Intuitively, I think this would have a large improvement in evening out cylinder mixtures as well as improving engine breathing. Aeroplane engines are more like static engines that car engines because they are nearly constant speed. It should be pretty easy to tune the inlets. If CASA didn't make walking over hot coals look more attractive, it would be interesting to have a go.
The hallmark text for intake systems is still "Scientific Design of Intake & Exhaust Systems" by Smith & Morrisson. Its been years and years since I have read it. I would have thought the optimal intake runner length on an engine like our TSIO 360 would be twice as long or more than they are standard. In cars the intake length is frequently compromised by bonnets, etc. Its why you often see intake runners that curve on top of the engine. But, I suspect you could double the length of the intake runners on most Continental engines without much difficulty. Intuitively, I think this would have a large improvement in evening out cylinder mixtures as well as improving engine breathing. Aeroplane engines are more like static engines that car engines because they are nearly constant speed. It should be pretty easy to tune the inlets. If CASA didn't make walking over hot coals look more attractive, it would be interesting to have a go.