Leaning Engines
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Davidt
AFAIK there is no general mechanical reason why a particular engine should not be run LOP. Any such advice is likely based on the standard plane having inadequate engine instrumentation to make it feasible or safe.
LOP, or even peak EGT, may not be achievable in practice if the fuel flow to the cylinders (or, to be more precise, the power developed by the individual cylinders) is badly matched. The result is excessive engine vibration.
I gather that most carb engines can't do LOP for the above reason, while most injected engines can, to varying degrees depending how well the injectors are matched up. Some people are lucky, most not.
GAMI will take your EDM700 data (you have to run a special flight test, details on their website) and sell you a set of injectors which are designed to make *your* engine balanced.
I don't have GAMIs but do fly LOP routinely at 45% to 65% power; what GAMIs would give me is the ability to run LOP at say 75% power. Reports from other GAMI owners suggest you get a smoother engine anyway. Cost about US$800 plus fitting.
There are reports of additional small fuel savings resulting probably from operation with a wide open throttle (e.g. at 8000ft, 65% power) which means the engine can suck the air in more easily.
AFAIK there is no general mechanical reason why a particular engine should not be run LOP. Any such advice is likely based on the standard plane having inadequate engine instrumentation to make it feasible or safe.
LOP, or even peak EGT, may not be achievable in practice if the fuel flow to the cylinders (or, to be more precise, the power developed by the individual cylinders) is badly matched. The result is excessive engine vibration.
I gather that most carb engines can't do LOP for the above reason, while most injected engines can, to varying degrees depending how well the injectors are matched up. Some people are lucky, most not.
GAMI will take your EDM700 data (you have to run a special flight test, details on their website) and sell you a set of injectors which are designed to make *your* engine balanced.
I don't have GAMIs but do fly LOP routinely at 45% to 65% power; what GAMIs would give me is the ability to run LOP at say 75% power. Reports from other GAMI owners suggest you get a smoother engine anyway. Cost about US$800 plus fitting.
There are reports of additional small fuel savings resulting probably from operation with a wide open throttle (e.g. at 8000ft, 65% power) which means the engine can suck the air in more easily.
Join Date: May 2002
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Davidt (or anyone else who has had an EDM-700 fitted)
I've long thought about getting one of these installed (in an Arrow IV).
JPI quote about 10 hours to install the basic kit on their web site - did yours take that or was it longer?
Can you just replace the existing EGT guage?
Is this a minor mod or a major mod? Currently waiting (and waiting) for CAA signoff of a major mod so not keen to get into this again in a hurry!
I notice you can download data from the unit to a PC. Does that involve getting to the back of it somehow or is there some sort of access from the front? And how long will the unit store data for? It'd be handy of you could download it at every 50 hour check which could be a month or 6 months. I'm quite interested in the data recording capability because my aircraft is rented out and it would be quite useful to try to get a view of what sort of abuse the engine gets!
I've long thought about getting one of these installed (in an Arrow IV).
JPI quote about 10 hours to install the basic kit on their web site - did yours take that or was it longer?
Can you just replace the existing EGT guage?
Is this a minor mod or a major mod? Currently waiting (and waiting) for CAA signoff of a major mod so not keen to get into this again in a hurry!
I notice you can download data from the unit to a PC. Does that involve getting to the back of it somehow or is there some sort of access from the front? And how long will the unit store data for? It'd be handy of you could download it at every 50 hour check which could be a month or 6 months. I'm quite interested in the data recording capability because my aircraft is rented out and it would be quite useful to try to get a view of what sort of abuse the engine gets!
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GRP
The EDM700 has an RS232 port (output only I believe; this "market leading product" is a really crude piece of 1970s technology!) which the installer should bring out onto a jack socket, DB9 or whatever.
You then get their windoze software from their website, and use that to receive the data. The data is compressed binary of some sort and the prog has to decompress it, and it expands each flight into a .csv file, plus you get a .txt file listing all the flights. There is also a program (basically an Excel macro) which displays the temps in a nice graph (although you can do that in Excel as with any other data).
On the EDM you get the option to download all data or just 'new' data (i.e. since the last download). The logging rate is configurable but basically you get of the order of 10-50 hours' of recording.
The UK installed price bears no relation to the US list price. Avionics shops get a nice mark-up for supply and installation. I suppose on a Private CofA plane you could do the really time consuming work (routing the 12-14 thermocouple cables halfway around the world
) yourself.
The EDM700 has an RS232 port (output only I believe; this "market leading product" is a really crude piece of 1970s technology!) which the installer should bring out onto a jack socket, DB9 or whatever.
You then get their windoze software from their website, and use that to receive the data. The data is compressed binary of some sort and the prog has to decompress it, and it expands each flight into a .csv file, plus you get a .txt file listing all the flights. There is also a program (basically an Excel macro) which displays the temps in a nice graph (although you can do that in Excel as with any other data).
On the EDM you get the option to download all data or just 'new' data (i.e. since the last download). The logging rate is configurable but basically you get of the order of 10-50 hours' of recording.
The UK installed price bears no relation to the US list price. Avionics shops get a nice mark-up for supply and installation. I suppose on a Private CofA plane you could do the really time consuming work (routing the 12-14 thermocouple cables halfway around the world
) yourself.
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Wasn't taught much about it in the private days, but was teaching it heavily as an instructor. Got tired of getting into an airplane , doing a run up and having the plugs foul. I lean on taxi, sometimes climb (depends on a/c and what altitude I'm going to), and always when I'm pulling 75% power or less, even down low.
When I was flying out of mountain strips in Idaho, Montana and the like you have to lead on take off to get full power. I have never trusted the lead of peak thing. I know some guys in Bonanza's that swear buy it, but it's not for me. The airplanes I usually flew it was a luxury to having a working EGT gage. My usual trick was lean until the engines changes tone, that would be about peak EGT then 3 half turns in. (each half turn is about 25 degrees, so you would be running about 50 -75 rich) Worked about right for most trainers I've flown in. The engine analyers mentioned are sweet but owners get paranoid about 10 degree's of difference in a cylinder. They flew the pants of the thing before with an old standard EGT now they have this toy and try to lean it for the sake of 2$ in fuel. Well the engine is about 30,000$ for the Beech so I'll just stick to a little on the rich side is O.K. for me. I'm not saying the gages aren't useful, just takes some skill to do it right. (which I don't think average joe pilot has, that's not flying the thing all the time) just my .02 cents
When I was flying out of mountain strips in Idaho, Montana and the like you have to lead on take off to get full power. I have never trusted the lead of peak thing. I know some guys in Bonanza's that swear buy it, but it's not for me. The airplanes I usually flew it was a luxury to having a working EGT gage. My usual trick was lean until the engines changes tone, that would be about peak EGT then 3 half turns in. (each half turn is about 25 degrees, so you would be running about 50 -75 rich) Worked about right for most trainers I've flown in. The engine analyers mentioned are sweet but owners get paranoid about 10 degree's of difference in a cylinder. They flew the pants of the thing before with an old standard EGT now they have this toy and try to lean it for the sake of 2$ in fuel. Well the engine is about 30,000$ for the Beech so I'll just stick to a little on the rich side is O.K. for me. I'm not saying the gages aren't useful, just takes some skill to do it right. (which I don't think average joe pilot has, that's not flying the thing all the time) just my .02 cents
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GRP
I only just had my EDM 700 installed and have only "flown" it for a few hours. So far dead impressed so much data. Down side you must have a safety pilot with you, you'll spend too much time staring at the pretty lights
I opted for the 700/6/lx which is a package with some optional extras( fuel flow,oat,oil temp) got mine from Harry Mendleshonn for just over £2k. If you look at the web site www.jpinstruments.com they quote 20 hours labour for a standard installation plus 6 hour for each option extra .
I combined mine with an annual and haven't had the bill yet.
Unit comes with a data port at the front + a lead to enable downloads of data to a Palm or Laptop. AQlso get a program to decompress the data and import it into progams like Excell so you can do spread sheets and graphs with it.
My installation is a minor mod, I think you will find that you cannot get rid of any of your original primary instruments as they are part of your Type certification or if you can that will take you into major mod territory.
They do a 701 which is not certified for my plane (Commander 114) which appears to be certified in the states as a primary instrument at least for some types. Contact JP if there is an FAA STC for what you want to do as I understand it the CAA will recognise that as a minor mod.
I ended up with three copies of JP's cd rom training video pm me if you want one.
Good luck
I only just had my EDM 700 installed and have only "flown" it for a few hours. So far dead impressed so much data. Down side you must have a safety pilot with you, you'll spend too much time staring at the pretty lights
I opted for the 700/6/lx which is a package with some optional extras( fuel flow,oat,oil temp) got mine from Harry Mendleshonn for just over £2k. If you look at the web site www.jpinstruments.com they quote 20 hours labour for a standard installation plus 6 hour for each option extra .
I combined mine with an annual and haven't had the bill yet.
Unit comes with a data port at the front + a lead to enable downloads of data to a Palm or Laptop. AQlso get a program to decompress the data and import it into progams like Excell so you can do spread sheets and graphs with it.
My installation is a minor mod, I think you will find that you cannot get rid of any of your original primary instruments as they are part of your Type certification or if you can that will take you into major mod territory.
They do a 701 which is not certified for my plane (Commander 114) which appears to be certified in the states as a primary instrument at least for some types. Contact JP if there is an FAA STC for what you want to do as I understand it the CAA will recognise that as a minor mod.
I ended up with three copies of JP's cd rom training video pm me if you want one.
Good luck
Grandpa Aerotart
Guys go here for all the info you'll ever need on Leaning. The engine specific articles are in a seperate box a little down on the RHS. Vast amounts of general good airmanship stuff too besides the mixture stuff.
Pelperch Engine Articles
I have Gamijectors and an EDM 700 in my Bonanza and run LOP all the time if not too high...climb LOP too if not going high. When cruising high and into a headwind I usually operate ROP to get the TAS up...but above about 7-8000 you can do whatever you like with the mixture nd not hurt your engine.
You CANNOT run LOP (lean of peak EGT) without an all cylinder monitor and, unless you're incredibly lucky and have balanced injectors, without Gamjectors.
Anyway I fly my Bonanza as per Deakin's articles and can categorically state that what he says is spot on.
LOP is easier than ROP and better for your engine.
The link below shows my EDM in cruise at 7500' LOP.The numbers shown are the hotest cylinder...compare the number to the standard CHT next to it. With only the standard gauges you have no idea whatis really going on inside the engine...that's why so few engines make TBO
My EDM
Not a great piccy as I was in light/ moderate turbulence at the time ducking around CBs over northern NSW heading home to Queensland.
The Data port is at 1 o'clock and the switch at 4 o'clock is for selecting between various scan modes.
Chuck.
Pelperch Engine Articles
I have Gamijectors and an EDM 700 in my Bonanza and run LOP all the time if not too high...climb LOP too if not going high. When cruising high and into a headwind I usually operate ROP to get the TAS up...but above about 7-8000 you can do whatever you like with the mixture nd not hurt your engine.
You CANNOT run LOP (lean of peak EGT) without an all cylinder monitor and, unless you're incredibly lucky and have balanced injectors, without Gamjectors.
Anyway I fly my Bonanza as per Deakin's articles and can categorically state that what he says is spot on.
LOP is easier than ROP and better for your engine.
The link below shows my EDM in cruise at 7500' LOP.The numbers shown are the hotest cylinder...compare the number to the standard CHT next to it. With only the standard gauges you have no idea whatis really going on inside the engine...that's why so few engines make TBO
My EDM
Not a great piccy as I was in light/ moderate turbulence at the time ducking around CBs over northern NSW heading home to Queensland.
The Data port is at 1 o'clock and the switch at 4 o'clock is for selecting between various scan modes.
Chuck.
Last edited by Chimbu chuckles; 4th May 2003 at 20:30.
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Chimbu -
You can run LOP without the EDM - that's why the IO-550 flight manual tells you to do it. In fact you probably have a greater chance of damaging the engine (burning valves etc) if you are not aggressive enough with LOP running since your EGT will be higher.
I agree, however, that the EDM removes all of the guesswork from the equation.
Running at 'moderate' power settings almost eliminates the possibilty of 'overleaning' most engines (i.e. they are happier really lean than over rich) - particulary with regard to worrying about LOP operations. However, I would always urge adherance to the manufacturers handbook for your motor if only to preserve the warranty.
You can run LOP without the EDM - that's why the IO-550 flight manual tells you to do it. In fact you probably have a greater chance of damaging the engine (burning valves etc) if you are not aggressive enough with LOP running since your EGT will be higher.
I agree, however, that the EDM removes all of the guesswork from the equation.
Running at 'moderate' power settings almost eliminates the possibilty of 'overleaning' most engines (i.e. they are happier really lean than over rich) - particulary with regard to worrying about LOP operations. However, I would always urge adherance to the manufacturers handbook for your motor if only to preserve the warranty.
Grandpa Aerotart
Of course it is possible to run LOP without an all cylinder monitor...in the vast majority of cases it won't be possile without tuned injectors...but why would you want to?
How would you know that all the cylinders have actually passed over to the lean side of peak?
How do you know that the CHT is reading the hottest cylinder?..look closely at the picture I have posted and see that the triplex CHT is reading 330 odd while cylnder 2 & 4 are around 370F.
Without an all cylinder monitor you could easily have several cylinders safely LOP, a couple at peak and a few just ROP...how would you know?
A good mate of mine who owns an Aztec bought himself an EDM760 after flying in my Bonanza but held off on the Gamjectors due costs...he was absolutely astounded at how inaccurate the triplex style CHTs were and how high the actual CHTs got when leaning as per the manual...upwards of 450F on a few cylinders!!
He recently fitted the Gamis to fix that before it cost him an engine.
My IO550b cost AUD40K to overhaul with new Millenium cylinders...+ the cost of buying/installing the Gamis/EDM...probably all up another AUD10K...you just can't afford not to have this technology in the biger bore, injected flat4s and 6s...it's a completely false economy.
In my Beechcraft Flight Manual it specifically states NOT to lean beyond peak...it specifically recommends 50F ROP for 'best economy...it is wrong...even CASA says it is wrong now that they have been to ADA and seen the IO540 running on the test stand at GAMI.
From a VERY senior CASA engineerin dude (hint THE most senior) "We have learned more about what is going on inside these engines in the last little while than inthe last 40 years!"
Warranty?
My EDM records the last 25 odd hours of engine data at 6 second intervals...every EGT & every CHT & Fuel Flow...if it fails and a warranty claim is made I have all the data I need to prove not one limitation has been exceeded.
I have had very experienced engineers tell me that I will damge my engine operating LOP...they can't tell me how, it just 'will'!
Chuck.
Appologies for the missing letters and gaps...think i's time fora new key board
How would you know that all the cylinders have actually passed over to the lean side of peak?
How do you know that the CHT is reading the hottest cylinder?..look closely at the picture I have posted and see that the triplex CHT is reading 330 odd while cylnder 2 & 4 are around 370F.
Without an all cylinder monitor you could easily have several cylinders safely LOP, a couple at peak and a few just ROP...how would you know?
A good mate of mine who owns an Aztec bought himself an EDM760 after flying in my Bonanza but held off on the Gamjectors due costs...he was absolutely astounded at how inaccurate the triplex style CHTs were and how high the actual CHTs got when leaning as per the manual...upwards of 450F on a few cylinders!!
He recently fitted the Gamis to fix that before it cost him an engine.
My IO550b cost AUD40K to overhaul with new Millenium cylinders...+ the cost of buying/installing the Gamis/EDM...probably all up another AUD10K...you just can't afford not to have this technology in the biger bore, injected flat4s and 6s...it's a completely false economy.
In my Beechcraft Flight Manual it specifically states NOT to lean beyond peak...it specifically recommends 50F ROP for 'best economy...it is wrong...even CASA says it is wrong now that they have been to ADA and seen the IO540 running on the test stand at GAMI.
From a VERY senior CASA engineerin dude (hint THE most senior) "We have learned more about what is going on inside these engines in the last little while than inthe last 40 years!"
Warranty?
My EDM records the last 25 odd hours of engine data at 6 second intervals...every EGT & every CHT & Fuel Flow...if it fails and a warranty claim is made I have all the data I need to prove not one limitation has been exceeded.
I have had very experienced engineers tell me that I will damge my engine operating LOP...they can't tell me how, it just 'will'!
Chuck.
Appologies for the missing letters and gaps...think i's time fora new key board
Last edited by Chimbu chuckles; 5th May 2003 at 21:52.
