Commercial Pilots who don't know about piston engines
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I don't think he *is* talking about a Normally aspirated engine though. Seems like he's speaking about a turbocharged engine.
If that $1,500 included labour, it means the part was worth about $100. If not, $150.
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im pretty sure any exhaust system will handle any temp that is Peak (as in, its never going to get any hotter) EGT.. considering steel exhaust pipes can glow red hot four hours on end without failure..
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All of this talk about hotter EGTs/TITs during LOP ops is interesting. Where I went to school, 50dF ROP and 50dF LOP were the same temperature! The OEMs recommended 50dF ROP! But then, I did go to school in the Southern US. Maybe I'm missing something!
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CTRE
I am going to PM you my phone number, you really would LOVE to do the class, and would find that all the religious hype is actually easy to see as fact of science but that is almost impossible to convey here on a post.
I look forward to helping you out a bit.
I am going to PM you my phone number, you really would LOVE to do the class, and would find that all the religious hype is actually easy to see as fact of science but that is almost impossible to convey here on a post.
I look forward to helping you out a bit.
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Walter
...ironic then, that on the previous page of this thread you excused yourself from providing data with this:
Over a decade ago, I asked Lycoming to provide data to back up some of their statements. I'm still waiting. Nada, Nunca, NOTHING. Why would someone not show their supporting data--unless they don't have any.
Anyone may chose whether or not they wish to take advantage of the opportunity to see and study that data, but to demand that it be provided free and at their whim seems a bit unreasonable.
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Oggers,
Sorry to burst your bubble, but if you search even here on pprune you will find somewhere Walter posting that he offered USD$1000 of his own cash for every piece of data that Lycoming had that disproved the data shown and collected from the GAMI/TAT dyno (and P&W, CW et al).
He put money where his mouth is. Still has the $$
You could do the same.
Sorry to burst your bubble, but if you search even here on pprune you will find somewhere Walter posting that he offered USD$1000 of his own cash for every piece of data that Lycoming had that disproved the data shown and collected from the GAMI/TAT dyno (and P&W, CW et al).
He put money where his mouth is. Still has the $$
You could do the same.
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I have only excused myself from providing the data on internet forums for ONE reason. Insufficient bandwidth. If you could explain to me how to post 16 hours of data presentation in a post on the forum, I'm all ears. In, literally, hundreds if not thousands of posts over 15 years, I have provided reams of data. BUT, as I said, I have no duty to provide anyone with a graduate level education for free. What I provide for free I do so because I want to help GA pilots improve their knowledge and safety.
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I have only excused myself from providing the data on internet forums for ONE reason. Insufficient bandwidth.
I have no duty to provide anyone with a graduate level education for free.
Moving on:
EGT does NOT affect valve temperature. We have hard data to prove that. The data came from a 1943 top secret NACA report done during WWII....valve temperature does NOT track EGT. This is 1943 data, not ours.
NACA754-fig7.jpg
The only exception to that was when the ignition timing was over advanced for the purposes of the test to 45BTDC. Even then, as the report points out “the fact that the temperature of the exhaust valve becomes greater than the temperature of the exhaust gas thermocouple is of no significance because the true exhaust gas temperature is greater than the thermocouple”.
We ran the test confirming this about 15 years ago.
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Oggers
I have worked with several operators and Chief Engineers over recent years, all of them are against the APS LOP theory and have warned their pilots of such.
I have no dog in this fight, but find it intriguing that the APS people treat their theory as valid and everybody else's opinion as sh1t
I have worked with several operators and Chief Engineers over recent years, all of them are against the APS LOP theory and have warned their pilots of such.
I have no dog in this fight, but find it intriguing that the APS people treat their theory as valid and everybody else's opinion as sh1t
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but find it intriguing that the APS people treat their theory as valid
Eddie, it would also be highly probable that the said aircraft operated by the said operators and maintained by said engineers lack proper engine monitoring.
Without proper engine monitoring I would warn most pilots to ignore APS LOP theory too. You are shooting in the dark a bit without instrumentation. That said I would trust Jabba, John or Walter to operate any engine I know of, regardless of instrumentation in any way they thought fit.
Without proper engine monitoring I would warn most pilots to ignore APS LOP theory too. You are shooting in the dark a bit without instrumentation. That said I would trust Jabba, John or Walter to operate any engine I know of, regardless of instrumentation in any way they thought fit.
Oggers
I have worked with several operators and Chief Engineers over recent years, all of them are against the APS LOP theory and have warned their pilots of such.
I have no dog in this fight, but find it intriguing that the APS people treat their theory as valid and everybody else's opinion as sh1t
I have worked with several operators and Chief Engineers over recent years, all of them are against the APS LOP theory and have warned their pilots of such.
I have no dog in this fight, but find it intriguing that the APS people treat their theory as valid and everybody else's opinion as sh1t
I felt so much safer after I put those pages in my aircraft's flight manual last week, having run the engine LOP in cruise ever since I got it years ago.
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Lead
Purposely obtuse or are you trying to draw me into this supercilious discussion?
Edit: in fact there's a private operator here that Dave knows well, Dave flew with him at Caboolture, and when he comes in for the next 100 inspect I will help him set the system as APS want.
Purposely obtuse or are you trying to draw me into this supercilious discussion?
Edit: in fact there's a private operator here that Dave knows well, Dave flew with him at Caboolture, and when he comes in for the next 100 inspect I will help him set the system as APS want.
Last edited by Eddie Dean; 3rd Apr 2016 at 07:47. Reason: See above
"Purposely obtuse"?
Not purposely, but I'm not sure of what I am being accused and against what, precisely, the "Chief Engineers" to whom you referred are warning.
You said:
Let me do my best to avoid any accusation of being obtuse: The "Chief Engineers" to whom you refer are ignorant, if their "warning" is on the basis that there is anything fundamentally more risky about running LOP than ROP (or peak) EGT.
I use the word "ignorant" to mean "lacking in knowledge" and "uniformed on the subject", per the Concise Oxford Dictionary. My shorthand for those definitions would be "stupid", but that's a personal view rather than one supported by dictionary definitions.
Sufficiently "un-obtuse" for you?
Not purposely, but I'm not sure of what I am being accused and against what, precisely, the "Chief Engineers" to whom you referred are warning.
You said:
I have worked with several operators and Chief Engineers over recent years, all of them are against the APS LOP theory and have warned their pilots of such.
I use the word "ignorant" to mean "lacking in knowledge" and "uniformed on the subject", per the Concise Oxford Dictionary. My shorthand for those definitions would be "stupid", but that's a personal view rather than one supported by dictionary definitions.
Sufficiently "un-obtuse" for you?
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I apologise, perhaps you are just ignorant. You missed the point and went on some belligerent rant, as always when you are presented with an apposing view.
BTW that is not the definition of obtuse.
BTW that is not the definition of obtuse.
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oggers, you are simply not correct.
Let me repeat your statement.
Time to put your glasses on, figure 8 clearly shows that statement is false.
Now have a close look at the full document; http://naca.central.cranfield.ac.uk/...report-754.pdf
This same data was repeated in tests done by Lycoming in the 1960's.
Look at how EGT and the valve temperature track. As you head towards Peak EGT (but still ROP) the valve temperature is falling. It did it back in 1943, it kept doing in in the 1960's and it does it in 2016 in my engine. Will keep doing it in 2020 too.
Now if you think APS data was just plucked out of our butts, think again. It is all backed by piles of data. I have stood at the panel of the engine dyno and even from the other side of the world watched the data of detonation testing (for the FAA) come streaming in live. I can assure you 100% the data is correct and has no opinion.
Now look carefully at the APS graphic which is provided for educational purposes and is relevant no matter what absolute values you care to use.
Have a close look at the relationship of the 1943 curves of valve temperature and just trust for a minute the APS curves. Ask yourself what tracks the same as the valve temperature?
Then ask yourself what the driver of this temperature is? Is it the Red, blue, black brown or green curve?
When you study this, and come up with an answer please let me know. We can take the next step in understanding.
Let me repeat your statement.
This is not correct. NACA-754 of 1943 shows clearly that valve temps track EGT. Figures 7a, b, and c and fig 8 all show it.
Now have a close look at the full document; http://naca.central.cranfield.ac.uk/...report-754.pdf
This same data was repeated in tests done by Lycoming in the 1960's.
Look at how EGT and the valve temperature track. As you head towards Peak EGT (but still ROP) the valve temperature is falling. It did it back in 1943, it kept doing in in the 1960's and it does it in 2016 in my engine. Will keep doing it in 2020 too.
Now if you think APS data was just plucked out of our butts, think again. It is all backed by piles of data. I have stood at the panel of the engine dyno and even from the other side of the world watched the data of detonation testing (for the FAA) come streaming in live. I can assure you 100% the data is correct and has no opinion.
Now look carefully at the APS graphic which is provided for educational purposes and is relevant no matter what absolute values you care to use.
Have a close look at the relationship of the 1943 curves of valve temperature and just trust for a minute the APS curves. Ask yourself what tracks the same as the valve temperature?
Then ask yourself what the driver of this temperature is? Is it the Red, blue, black brown or green curve?
When you study this, and come up with an answer please let me know. We can take the next step in understanding.
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According to the 1943 NACA report referenced, those who think that valve temp is in any way related to EGT must reconcile the fact that as EGT is going UP from 25dF ROP to peak EGT the valve temperature is going DOWN. This is definitive evidence that the two are NOT related. Maybe one needs to look at the data more closely. This was confirmed by Lycoming in 1966 and again by GAMI more recently.
Valve temp is NOT related to EGT, it is related to something else... a study of the chart Jabber posted will reveal the answer.
The problem is that the physics are everywhere the same. Opinions may not be.
The second problem is that one may choose to believe unsupported opinions or the hard data. To each, his own.
As for providing a link, that is easy. Go the the APS website and sign up for the online course where 16+ hours of hard DATA are presented. It is the equivalent of a semester course, not a simple SAE "paper." Where I went to school, one had to pay for the education.
Dig in or not. Educate or not. It's a call each must make for themselves and it matters not to anyone else.
We have spent a decade and a half dealing with the types of unsupported statements made in this thread and in not a single instance have the unsupported opinions held up to the science. Take your best shot. Send us some data.
Valve temp is NOT related to EGT, it is related to something else... a study of the chart Jabber posted will reveal the answer.
The problem is that the physics are everywhere the same. Opinions may not be.
The second problem is that one may choose to believe unsupported opinions or the hard data. To each, his own.
As for providing a link, that is easy. Go the the APS website and sign up for the online course where 16+ hours of hard DATA are presented. It is the equivalent of a semester course, not a simple SAE "paper." Where I went to school, one had to pay for the education.
Dig in or not. Educate or not. It's a call each must make for themselves and it matters not to anyone else.
We have spent a decade and a half dealing with the types of unsupported statements made in this thread and in not a single instance have the unsupported opinions held up to the science. Take your best shot. Send us some data.
Last edited by Walter Atkinson; 4th Apr 2016 at 02:04.
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LOP theory?????
That is truly funny.
It's factual. One might enjoy reading Taylor's two-volume engineering texts--or Haywood's texts.
I've read both.
It's true. There really is a time machine and we've all gone back in time. This thread proves it.
That is truly funny.
It's factual. One might enjoy reading Taylor's two-volume engineering texts--or Haywood's texts.
I've read both.
It's true. There really is a time machine and we've all gone back in time. This thread proves it.