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12-10-2013, 11:28 AM
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Join Date: Jan 2005
Location: Granbury Texas
Posts: 1,136
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Maybe, I will be up there this weekend so if I can help give me a call. We can also get a few of the other 10 owners on the field to give us their thoughts. If your going to the chapter event Saturday night I'm sure we can find a few opinions.
If the engine was running lean the temps would be high so I am pretty sure that's not it. Just different from my engine. I am also under 100 hours and don't lean as aggressively as others might.
Pat
Last edited by Pat Stewart : 12-10-2013 at 11:30 AM.
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12-11-2013, 06:08 AM
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Join Date: Jan 2005
Location: Granbury Texas
Posts: 1,136
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David,
I enjoyed talking with you yesterday on face time and although Johns issue may be different the feedback you provided was appreciated. I will check out the training event in Ada Ok in March and see if I can fly my 10 up there.
Pat
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Originally Posted by RV10inOz
Bart,
Send me a copy of the engine monitor file. davidbrown 'at' advancedpilot.com
There are a couple of things I can think of that will cause this, and even some rare bizarre things.
Can you also tell me the following;
Stage of flight i.e. just after TOC ?
Plugs: Brand, when were they gapped last.
Mags: Are the Mags or EI's
Fuel: What type are you using
EMS data log time interval
If you can, pin point the exact time these events occur in the data.
I will see what I can see?. 
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12-11-2013, 06:20 PM
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Join Date: May 2008
Location: Brisbane Qld. Aust.
Posts: 2,271
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Gentleman,
I am writing this post to correct a few myths and misunderstandings about running in engines, fuel flow and EI's.
First of all, the little bit of advance that makes LOP ops better is in the order of a couple of degrees, however this is only good when LOP, for you ROP guys it is actually less of a good thing especially when running around 50dF ROP.
Fuel flow will vary depending on altitude, but for typical cruise altitudes of around 7500-9500' when running appropriately LOP, will be 11.0-10.5GPH. This is regardless of the type of ignition you are running.
As for breaking in the engine, you want to do this with low peak pressures and high mean effective pressures. This means the break in happens over a wider pass of the piston/cylinder, without the high peak.
Given that we can generate the same torque and BMEP by varying the peak pressure and theta PP, which combination is going to give us better mean effective pressures and lowest peak pressures? Which method is going to give us lower CHT's? Which method is going to give us cleaner rings and cylinders?
If the answer to the above was Rich of Peak run in, I would thoroughly endorse it. However the answer is actually the opposite. So you are far better to run in your engine LOP. Sure at takeoff full rich, but at 1500-2000' a big mixture pull and run in at high HP LOP. The choices are 75% or more power, either full rich or 80dF LOP. Take your pick.
Of course you need to have good F/A ratios in order to do this, and there is no problem doing this on your second flight to determine if you have a good gami spread. If you do not get it fixed and continue flying the phase 1.
This notion that
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but I'm not going to run LOP for awhile due to having a new engine.
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?. is complete nonsense and at odds with the science and data. It is however consistent with popular belief!
I frequently remined myself during discussions such as these that it's often true that no amount of data can replace the comforts of a closely held superstition.
Below is a photo I post regularly, this would be a perfect break in setup, so long as the air was smooth, or adjust accordingly by going a fraction higher. 
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______________________________
David Brown
DYNON Authorised Dealer and Installer
The two best investments you can make, by any financial test, an EMS and APS!
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12-11-2013, 07:38 PM
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Join Date: Apr 2009
Location: USA
Posts: 1,499
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My new factory engine with unbalanced injectors runs fine at 30-40F LOP. I doubt any new factory engine will run smooth at 80F LOP for break-in as you mentioned above.
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Good judgment comes from experience, and a lot of that comes from bad judgment.
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12-11-2013, 09:15 PM
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Join Date: May 2008
Location: Brisbane Qld. Aust.
Posts: 2,271
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Confucius say: Do not tell man something impossible when he already doing it!
Wayne your doubts are well founded?.only some of the time.
In my case with a factory Lycoming you would be forgiven for making that satement, it was a shocker, so bad we could not even do a GAMI lean test and had to do some guesses to start with just to get anything near peak EGT.
Yet a year or so later while flight testing another RV10 with a stock factory IO540?..0.2GPH spread and would run happily 80dF LOP at 2000'. I was stunned! An RV7 owner with an Aerosport Power engine down here gets 0.0 spread, it is that good. I suspect that AP did a great job on the dyne before shipping, or they just got lucky.
Wayne, your new engine runs fine 30-40dF LOP, but at what MP and RPM? This varies with power(Altitude). If you can do that at 10'000 feet that suggests a good spread, and chances are at 1000' as shown above you can also run down to 100dF LOP.
30-40dF LOP at 10,000' is vastly different to 1,000'.
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______________________________
David Brown
DYNON Authorised Dealer and Installer
The two best investments you can make, by any financial test, an EMS and APS!
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12-11-2013, 10:09 PM
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Join Date: Apr 2009
Location: USA
Posts: 1,499
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16,500', DA= 18,370', 16.1" mp, 2430 rpm, 7.9 gph, IAS= 105 kts, TAS= 136 kts, 16 nmpg with a 14 kt headwind, +6 degrees pitch, 225F cowl exit temp(hottest ever), CHT= 307-331F, OAT= 32F, gross weight, near aft cg limit. That is the highest that we have been and it ran smooth 30-40 LOP. Mine does not want to run smooth beyond 40-50F down low. We lose a lot of speed running LOP, so can't imagine wanting to run any leaner. We are very happy with the engine and plane.
__________________
Good judgment comes from experience, and a lot of that comes from bad judgment.
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12-12-2013, 12:35 AM
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Join Date: May 2008
Location: Brisbane Qld. Aust.
Posts: 2,271
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Wayne, I see your problems.
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We lose a lot of speed running LOP
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I bet you do!! And this is the problem, lack of education and understanding. A bit like Kevin Horton the other day and the old 50dF LOP SOP thing.
you had a DA of 18000' and at 40LOP it was almost stopped! 10dF LOP and no more. In fact 75dF ROP up there would be better.
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so can't imagine wanting to run any leaner.
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No doubt at all!
Tell me this, what is your procedure for leaning and setting the LOP cruise setting, and I might be able to help you out.
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Mine does not want to run smooth beyond 40-50F down low.
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And this is significant, also. I suspect a problem here that can be corrected.
How many hours on the engine?
What plugs do you use?
How long since they were gapped?
How many hours on them?
Can you send me a EMS data file?
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______________________________
David Brown
DYNON Authorised Dealer and Installer
The two best investments you can make, by any financial test, an EMS and APS!
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12-12-2013, 05:20 AM
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Join Date: Oct 2005
Location: 08A
Posts: 9,500
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Quote:
Originally Posted by RV10inOz
As for breaking in the engine, you want to do this with low peak pressures and high mean effective pressures. This means the break in happens over a wider pass of the piston/cylinder, without the high peak.
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Can you quantify this statement? Cylinder pressure plots or a data table? In numbers, can you show us the difference in pressures (peak and mean) between the two operating schemes?
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So you are far better to run in your engine LOP. Sure at takeoff full rich, but at 1500-2000' a big mixture pull and run in at high HP LOP. The choices are 75% or more power, either full rich or 80dF LOP. Take your pick.
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You better hope your audience fully understands that at full power, there is a very good chance it is going to detonate in the mixture region between 50 ROP and 50 LOP, and that region may extend quite a lot further with increased compression ratio or advanced ignition. Want to see the chart again?
You're asking the pilot of a brand new, unfamiliar airplane to make a rapid mixture pull to a point close to cutoff, probably with untuned injectors, while close to the ground. Failure to do the Big Pull in a rapid manner (i.e. slowly easing up to peak from the rich side) risks engine damage. Isn't that asking a bit much?
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I frequently remined myself during discussions such as these that it's often true that no amount of data can replace the comforts of a closely held superstition.
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Take a risk...show us the data anyway.
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Dan Horton
RV-8 SS
Barrett IO-390
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12-12-2013, 06:01 AM
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Join Date: Apr 2009
Location: USA
Posts: 1,499
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Quote:
Originally Posted by RV10inOz
Wayne, I see your problems.
I bet you do!! And this is the problem, lack of education and understanding. A bit like Kevin Horton the other day and the old 50dF LOP SOP thing.Thank you.
you had a DA of 18000' and at 40LOP it was almost stopped! 10dF LOP and no more. In fact 75dF ROP up there would be better.I agree.
No doubt at all!
Tell me this, what is your procedure for leaning and setting the LOP cruise setting, and I might be able to help you out.We lean from 663', flowing 25.6 gph, to our usual cruise altitude of 12,500' at a takeoff EGT of 1250F, 2700 RPM. Once at cruise, RPM to 2200-2450, WOT, pull mixture to get me close noting normal FF of 9.5-10.5 gph(yes, I am always below 75%), then slowly lean using GRT to 30-40F LOP. Typically cruise at 150-158 KTAS.
And this is significant, also. I suspect a problem here that can be corrected.
How many hours on the engine? 125 since Dec 1, 2011 thanks to our great economy.
What plugs do you use?massive on top and fine wire on bottom
How long since they were gapped? 25
How many hours on them? 125 on massive/25 on fine wire
Can you send me a EMS data file?No
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Yes, I need to get fuel injectors balanced. Changing to six fine wires gave me another 10F LOP before getting rough.
__________________
Good judgment comes from experience, and a lot of that comes from bad judgment.
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12-12-2013, 09:31 PM
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Join Date: May 2008
Location: Brisbane Qld. Aust.
Posts: 2,271
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Dan,
Take a risk and show you the data. Sure when you sign a NDA which covers a whole load of things, and you get involved with a certification project that clearly shows everything you could want to know and more, why not!
Simpler option would be pony up with the cash and do the next course in Ada OK and George will show you real live data of the sort you want to see. I have seen plenty of it and quite a lot lately. But that is not for public consumption.
Having said that I can pull some info from the course which are straight from the dyno hard data, or even some of John Deakins old articles.
But let me answer a question or two for you. You asked;
Quote:
Quote:
Originally Posted by RV10inOz View Post
As for breaking in the engine, you want to do this with low peak pressures and high mean effective pressures. This means the break in happens over a wider pass of the piston/cylinder, without the high peak.
Can you quantify this statement? Cylinder pressure plots or a data table? In numbers, can you show us the difference in pressures (peak and mean) between the two operating schemes?
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And took only a small snippet of the message, so let me answer your question with the benefit of my statement displayed for all the others reading silently on the sideline. I will highlight the salient points.
David Brown said..
Quote:
As for breaking in the engine, you want to do this with low peak pressures and high mean effective pressures. This means the break in happens over a wider pass of the piston/cylinder, without the high peak.
Given that we can generate the same torque and BMEP by varying the peak pressure and theta PP, which combination is going to give us better mean effective pressures and lowest peak pressures? Which method is going to give us lower CHT's? Which method is going to give us cleaner rings and cylinders?
If the answer to the above was Rich of Peak run in, I would thoroughly endorse it. However the answer is actually the opposite. So you are far better to run in your engine LOP. Sure at takeoff full rich, but at 1500-2000' a big mixture pull and run in at high HP LOP. [b]The choices are 75% or more power, either full rich or 80dF LOP. Take your pick.
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If you want to see this data for yourself, on the Friday night, this very demonstration is shown between 15min and 17min on the dyno video run. I can't upload that video here, so let me lift the figures for you.
The first Data block I have noted is at peak or just lean of peak, in an attempt to keep the HP the same rather than the reduced power and obviously even lower PSI's. The second is full rich.
1. MP=31" RPM=2400 BMEP 133.9 BHP=219 ICP's ranged 600-620PSI
2. MP=31" RPM=2395 BMEP 136.6 BHP=223 ICP's ranged 750-780PSI
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You better hope your audience fully understands that at full power, there is a very good chance it is going to detonate in the mixture region between 50 ROP and 50 LOP, and that region may extend quite a lot further with increased compression ratio or advanced ignition. Want to see the chart again?
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Well I think you are misleading the audience, but lets look at those graphs, and no thanks I have a copy. They show a data point at precisely where we teach detonation is most likely to occur. Right around 35-50dF ROP and they draw a line from one data point to another and give you a misleading idea that the detonation is still going on 40-50dF LOP. And that is simply not true.
By the way the Lycoming data comes from a source that is far behind in my opinion the FAA test centre or the GAMI one, they do not use the currently accepted detonation algorithms and that graph you refer to only shows frequency (Hz) of events. It does nothing for intensity and this is the key point. George has demonstrated this on his test stand to the FAA, and it is like asking yourself, in a hail storm which deposits hail on your car, or better still if you are a car salesman with a yard full of cars. And it deposits 1000 hail stones weighing 0.2grams each on your yard. The other choice is 10 hail stones at 20grams each. Which one is going to give your insurance company the shivers? So intensity matters. Frequency not so much.
Your statement above is somewhat accurate in that detonation occurs in the renege from 50ROP to 50LOP, but it is no more accurate than a statement like 200ROP to 100LOP. A truer statement might be something like 75ROP and 10ROP.
So back to the claim that doing a BMP while running in your engine will be running the engine where "there is a very good chance it is going to detonate in the mixture region between 50 ROP and 50 LOP", and how on earth in a few seconds you are going to heat up the oil, heat up the CHT's create 30"MP and 2400 long enough for even one detonation event to take place? I fail to see how that is even remotely possible. For the audience out there, running a conforming engine on conforming 100LL and doing a BMP, even with CHT's over 400dF we have never seen detonation happen and even with purposely driven high oil, air, CHT and the ability to run 33" or more we have not seen this with a BMP.
OK next one,
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You're asking the pilot of a brand new, unfamiliar airplane to make a rapid mixture pull to a point close to cutoff, probably with untuned injectors, while close to the ground. Failure to do the Big Pull in a rapid manner (i.e. slowly easing up to peak from the rich side) risks engine damage. Isn't that asking a bit much?
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A You're asking the pilot of a brand new, unfamiliar airplane to make a rapid mixture pull to a point close to cutoff No, I am giving the pilot the option, who is at least familiar enough to have already made his first or second flight, the confidence to make a smooth mixture pull through to a deceleration, (easy to feel), and park the engine somewhere safe for a minute, while he determines if he does have good enough fuel / air ratio's. If he does not he will soon know and shove the mixture back in and continue on full rich. At no time is the mixture anywhere near idle cutoff, and I can be sure that if he got that far it would not be for long.
B probably with untuned injectors Probably so, the only way they would have been tuned is if they were done by Aerosport or Riverina or someone on their engine test cell, but it is possible to have decent enough F/A ratio's out of the box sometimes. Maybe this would be a good time to sort that out?
C while close to the ground For the purposes of doing aero's or stalls on your second flight 1500-2000' I would surely call that close to the ground. But to manipulate the mixture knob? Surely you are kidding me. If you or they are that scared they may not have fastened it right to the FCU, do it 2000' above the field.
D Failure to do the Big Pull in a rapid manner (i.e. slowly easing up to peak from the rich side) risks engine damage. I think if you had done any of this even doing it slowly on either the FAA's or GAMI's test cell you would not be so scared and willing to believe the BS Lycoming have printed. Even doing it slowly over 30 seconds is not going to hurt anything. The problem is by doing it slowly is not anything to do with engine harm, it is that you will not feel the deceleration at all when going safely into LOP territory. So the BMP is not any use if it is a SMP.
E Isn't that asking a bit much? No not at all. I suggest you email the editor of the AOPA's Australian magazine http://www.aopa.com.au/magazine and ask her about her first BMP done overwater at 1500' and see how she responds. So all the smarter tougher and more macho test pilots should be able to cope.
Take a Risk Dan??go see the data for yourself. http://www.advancedpilot.com/store.html If you don't learn anything at all, Deakin will write you a cheque.
__________________
______________________________
David Brown
DYNON Authorised Dealer and Installer
The two best investments you can make, by any financial test, an EMS and APS!
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