Commercial Pilots who don't know about piston engines
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actually, LOP Theory is correct terminology.
Theory. 1.
a coherent group of tested general propositions, commonly regarded as correct, that can be used as principles of explanation and prediction for a class of phenomena:
Theory. 1.
a coherent group of tested general propositions, commonly regarded as correct, that can be used as principles of explanation and prediction for a class of phenomena:
Errrm, no. There are no "principles of explanation and prediction" here.
We don't say that the sun rising in the east is a "theory", notwithstanding that we predict it will happen each day and we have explanations for it.
We don't say that the sun rising in the east is a "theory", notwithstanding that we predict it will happen each day and we have explanations for it.
Join Date: Oct 2014
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Errrrrm no, the sun rising in the East is fact.
Where as LOP is by definition a theory that holds true as ultralights has written.
BTW thanks "old mate" that was a great and enlightning discussion.
Where as LOP is by definition a theory that holds true as ultralights has written.
BTW thanks "old mate" that was a great and enlightning discussion.
So "ROP" is a "theory" as well? 
Me an intellectual? Bwaaahaaaahaaaa 
Maybe we just have to agree that anything to do with reciprocating engines is ... faith-based ...
Maybe we just have to agree that anything to do with reciprocating engines is ... faith-based ...
Join Date: Apr 2005
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So all that old data what fuel is that based on...
You could say in the past people may have had access to 100/130 avgas so 100 octane lean of peak and 130 octane rich of peak.
If that fuel was still available would the LOP discussion still be going on?
Ducks and hides.....
You could say in the past people may have had access to 100/130 avgas so 100 octane lean of peak and 130 octane rich of peak.
If that fuel was still available would the LOP discussion still be going on?
Ducks and hides.....
Last edited by sillograph; 5th Apr 2016 at 13:18.
Join Date: Jul 2007
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The fuel used matters not, the relationships are all the same, be it 100/130, 100LL ordinary mogas or G100UL. The LOP/ROP relationships remain.
It is all about detonation margin and using the suitable fuel for your engine.
It is all about detonation margin and using the suitable fuel for your engine.
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***
All I was saying was if we could still get 100/130 fuel the majority may still prefer the extra power of 130 octane but the only way to get it would be ROP.
***
130 octane does not result in extra power over 100LL. Period. It does offer a wider detonation margin.
The 130 would run very nicely LOP.
One should understand that if I limit CHTs to a given temperature, say 380dF, I can get MORE power out of my engine LOP than ROP. I routinely fly my TNIO-550 at 85-90% power LOP. I can only get about 75% power ROP at that operational CHT limit. Obviously, I'm flying faster at 90% power than 75% power.
There are so many misconceptions about this stuff.
For example, operating an engine across the entire mixture spectrum has been a fact of science since the invention of the internal combustion engine. This is not new. It is not a theory. It is a fact of science, provable by any investigator--which has been done thousands of times.
Of course it is also true that no amount of science can overcome the comforts offered by a closely held superstition.
All I was saying was if we could still get 100/130 fuel the majority may still prefer the extra power of 130 octane but the only way to get it would be ROP.
***
130 octane does not result in extra power over 100LL. Period. It does offer a wider detonation margin.
The 130 would run very nicely LOP.
One should understand that if I limit CHTs to a given temperature, say 380dF, I can get MORE power out of my engine LOP than ROP. I routinely fly my TNIO-550 at 85-90% power LOP. I can only get about 75% power ROP at that operational CHT limit. Obviously, I'm flying faster at 90% power than 75% power.
There are so many misconceptions about this stuff.
For example, operating an engine across the entire mixture spectrum has been a fact of science since the invention of the internal combustion engine. This is not new. It is not a theory. It is a fact of science, provable by any investigator--which has been done thousands of times.
Of course it is also true that no amount of science can overcome the comforts offered by a closely held superstition.
Join Date: Apr 2005
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So what happens when one of your engines egt probes fail on a system with a probe for each cylinder. Going off the gami supplement in Poh would that mean you now have to go back to ROP to be compliant as you now don't meet the requirements of the supplement until the probe is replaced. This could be any where from less than an hour to say 10 hours flying if you can't get to a shop due to scheduling. And what is the cost of said probe, roughly $200 each plus labour. The reason I say this we have installed such systems and this problem pops up every month or so.
Then there is the issue of 10 different drivers flying the aircraft I just can't see it working commercially due to this, looks fine for say owner pilot or maybe two pilots or owners.
Turbines are just better from every angle, and with the cost of the big lycomming the turbine is fast becoming a more viable option.
Then there is the issue of 10 different drivers flying the aircraft I just can't see it working commercially due to this, looks fine for say owner pilot or maybe two pilots or owners.
Turbines are just better from every angle, and with the cost of the big lycomming the turbine is fast becoming a more viable option.
Join Date: Jul 2007
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Sillo,
Couple of things here, the calorific values of fuels varies by tiny amounts, not worth the discussion point. The different octane ratings means you get to use the fuel with higher boost or higher compression ratio to achieve more power, while maintaining detonation margins that are acceptable. And acceptable varies from airplane to race car and everything in between.
As for if an EGT probe fails? Well no, once you are "known to be LOP" a probe failure matters not, because validation from all the others, your fuel low etc…..means the EGT probe is just validation of a know state.
You can comply with the POH supplement without even looking at the egt info if you want.
Couple of things here, the calorific values of fuels varies by tiny amounts, not worth the discussion point. The different octane ratings means you get to use the fuel with higher boost or higher compression ratio to achieve more power, while maintaining detonation margins that are acceptable. And acceptable varies from airplane to race car and everything in between.
As for if an EGT probe fails? Well no, once you are "known to be LOP" a probe failure matters not, because validation from all the others, your fuel low etc…..means the EGT probe is just validation of a know state.
You can comply with the POH supplement without even looking at the egt info if you want.
Then there is the issue of 10 different drivers flying the aircraft I just can't see it working commercially due to this, looks fine for say owner pilot or maybe two pilots or owners.
Much as I hate to say it, it is a private owners thing mostly. Every flight review I conduct I casually ask about the pilots leaning policy, then I listen to "standard industry practice" or "that's what I was taught" and I ponder the task of changing established practices. That said, if ever I operate or manage an aviation business again, I would be looking at getting the education and doing the downloading because the savings would well be worth it subject to pilot turnover and other commercial considerations.
So let's say the deliberate decision is to "run ROP".
How do you know each cylinder is ROP?
And why would you make a deliberate decision to run each cylinder ROP, when the science and data prove that the mixture setting that will give the engine the hardest beating it can possibly be given is ROP?
It defies all logic. (Not an unusual circumstance in Australian GA though ...)
How do you know each cylinder is ROP?
And why would you make a deliberate decision to run each cylinder ROP, when the science and data prove that the mixture setting that will give the engine the hardest beating it can possibly be given is ROP?
It defies all logic. (Not an unusual circumstance in Australian GA though ...)
How do you know each cylinder is ROP?
Yes it is quite bizarre.
Apparently you'll be 'safe' and 'legal' if you believe all cylinders are ROP and cooler than they would be if LOP, but you'll be 'unsafe' and 'illegal' if you know that the cylinders are LOP and cooler than they would be if ROP.
Apparently you'll be 'safe' and 'legal' if you believe all cylinders are ROP and cooler than they would be if LOP, but you'll be 'unsafe' and 'illegal' if you know that the cylinders are LOP and cooler than they would be if ROP.
Join Date: Jul 2007
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Gidday Aussie Bob,
There are several charter operators doing it quite successfully, and all with CASA approved ops manuals. I know, because I helped them do it
It is not hard. As you know, running accurately LOP is much easier than ROP if you want to do it efficiently. I know one operator who is making several 6 figures more per year in less fuel and more importantly less maintenance. Here is what they did;
1. Chief Engineer did APS class.
2. Started fitting JPI's and GAMI's through the fleet (mostly twins) and installing better baffle kits.
3. Sent Chief Pilot to the next APS class.
4. Started to pay for the GAMI's, JPI's and Baffles in about 9 months or something like that.
5. Re-wrote ops manuals and educated pilots in house on simple and dare I say it "cook book" operations.
6. Reports to me that after 3 years they are doing a fraction of the cylinder work, and between better operating practises, better data analysis (not just asking pilots what they think is happening) they are saving several hundred thousand per year.
How to fly SAFER and make a profit in GA???? Well the cut throat competitors probably can't work it out, but they have not dropped their prices, so all of a sudden what was just profitable is now a viable business.
It is not rocket science, but it does involve a bit of science and not mythology.
Hope you are having fun down there
There are several charter operators doing it quite successfully, and all with CASA approved ops manuals. I know, because I helped them do it
It is not hard. As you know, running accurately LOP is much easier than ROP if you want to do it efficiently. I know one operator who is making several 6 figures more per year in less fuel and more importantly less maintenance. Here is what they did;
1. Chief Engineer did APS class.
2. Started fitting JPI's and GAMI's through the fleet (mostly twins) and installing better baffle kits.
3. Sent Chief Pilot to the next APS class.
4. Started to pay for the GAMI's, JPI's and Baffles in about 9 months or something like that.
5. Re-wrote ops manuals and educated pilots in house on simple and dare I say it "cook book" operations.
6. Reports to me that after 3 years they are doing a fraction of the cylinder work, and between better operating practises, better data analysis (not just asking pilots what they think is happening) they are saving several hundred thousand per year.
How to fly SAFER and make a profit in GA???? Well the cut throat competitors probably can't work it out, but they have not dropped their prices, so all of a sudden what was just profitable is now a viable business.
It is not rocket science, but it does involve a bit of science and not mythology.
Hope you are having fun down there
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For example, operating an engine across the entire mixture spectrum has been a fact of science since the invention of the internal combustion engine. This is not new. It is not a theory. It is a fact of science, provable by any investigator--which has been done thousands of times.
This video explains it: the scientific method.
Please note #3, of the so-called 10 commandments: "Thou shalt back up thy statements with evidence...just claiming something is a fact doesn't make it a fact".