A Little Gem from CASA Experts
From first-hand experience: The lawyers are going to get your house if you have an engine failure running your engine/s on folklore, in accordance with the POH or otherwise. The only difference is whether you have a provable cross-claim against the publishers of folklore in the POH. That argument will cost you your house, anyway.
I envy you your blissful ignorance.
I envy you your blissful ignorance.
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A friend of mine works at Katherine Aviation where they operate 210s and Barons lean of peak with GAMIs fitted. Apparently it's all part of their SOPs/in their operations manual. CASA must have signed off on this right?
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Lead Balloon
The POH is not folklore, but a legal document. The defence that a dentist at APS gave me operational engine management guidelines, not accredited by CASA, or the manufacturer, means you will end up enjoying the bliss of a trailer park, as you say.
The POH is not folklore, but a legal document. The defence that a dentist at APS gave me operational engine management guidelines, not accredited by CASA, or the manufacturer, means you will end up enjoying the bliss of a trailer park, as you say.
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Not actually correct, CASA do not approve Operations Manuals, they merely accept them.
You’re obviously sure of your opinion, tio540. Those reading PPRuNe will rely on it. 
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I am all for a robust discussion.
The PA31-350 POH actually permits LOP, one of three options for leaning, so here we might even agree. However, the actual Lycoming engine manufacturer does not approve LOP.
The Continental service bulletin cites engine longevity as an issue when describing LOP, and recommends this only in extreme long range operations, and only occasionally.
I should add I have absolutely no engineering quals, and am usually wrong with most things.
The PA31-350 POH actually permits LOP, one of three options for leaning, so here we might even agree. However, the actual Lycoming engine manufacturer does not approve LOP.
The Continental service bulletin cites engine longevity as an issue when describing LOP, and recommends this only in extreme long range operations, and only occasionally.
I should add I have absolutely no engineering quals, and am usually wrong with most things.
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Leadballoon
In your opinion. Now for the facts:
If the engine has detonated visual signs like broken spark plug porcelains or broken ground electrodes are dead giveaways and call for further examination or engine disassembly. Engine Basics: Detonation and Pre-Ignition by Allen W. Cline
The typical cracked core nose condition shown may be caused by improper cleaning or gapping procedures and by detonation. Champion Aerospace Aviation Service Manual
Detonation is an explosion of the combustion charge in an uncontrolled sudden manner. This condition may damage the spark plug electrodes or crack the insulator nose as well as destroy the engine if permitted to continue. Tempest Aviation Spark Plugs
It is a fact that detonation causes cracked insulators. It is also a fact that running lean of peak at high power puts an engine inside its certified detonation envelope. Note I am not saying LOP causes detonation, I am saying LOP at high power can cause detonation, for instance when a pilot forgets to set the mixture full rich before take off or go-around on a hot day.
A complete misunderstanding of what caused the cracked spark-plug insulators.
If the engine has detonated visual signs like broken spark plug porcelains or broken ground electrodes are dead giveaways and call for further examination or engine disassembly. Engine Basics: Detonation and Pre-Ignition by Allen W. Cline
The typical cracked core nose condition shown may be caused by improper cleaning or gapping procedures and by detonation. Champion Aerospace Aviation Service Manual
Detonation is an explosion of the combustion charge in an uncontrolled sudden manner. This condition may damage the spark plug electrodes or crack the insulator nose as well as destroy the engine if permitted to continue. Tempest Aviation Spark Plugs
It is a fact that detonation causes cracked insulators. It is also a fact that running lean of peak at high power puts an engine inside its certified detonation envelope. Note I am not saying LOP causes detonation, I am saying LOP at high power can cause detonation, for instance when a pilot forgets to set the mixture full rich before take off or go-around on a hot day.
I wish I’d said that.
Oh wait, I did, or most of it to the extent it’s accurate:
I listed the top 3 causes, not the only causes.
The most efficient way to punish an engine is to run it ROP, but not far enough ROP. As I said, the surest way to cause detonation in my engine is to run it where the POH says to run it.
You can also punish an engine if don’t you run it far enough LOP. But you will never be giving it as good a thrashing as you could ROP.
Oh wait, I did, or most of it to the extent it’s accurate:
To the extent that the way in which an engine is run may cause insulator cracking, (3) would be running the engine RICH OF PEAK, but not far enough rich of peak.
The most efficient way to punish an engine is to run it ROP, but not far enough ROP. As I said, the surest way to cause detonation in my engine is to run it where the POH says to run it.
You can also punish an engine if don’t you run it far enough LOP. But you will never be giving it as good a thrashing as you could ROP.
Note I am not saying LOP causes detonation, I am saying LOP at high power can cause detonation, for instance when a pilot forgets to set the mixture full rich before take off or go-around on a hot day.
Walk me through how I’d get detonation if I went to full throttle to go around, without touching the mixture. Note that the engine would in that case be set precisely where it was set when I arrived in the circuit. And I can see on the engine monitor that the CHTs are lovely and cool.
I might not have as much power as I could safely draw from the engine if I leave the mixture LOP, which is why I would as SOP go full rich. But note I’m not going full rich to avoid detonation LOP, but rather to get more power at a safe mixture.
And not I’m not setting the mixture to get maximum power - around 25C ROP - as that would be the mixture that would maximise the likelihood of .... detonation, particularly if I’ve forgotten to set the prop to maximum RPM.
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Who said “peak EGT is the worst place to run your engine”?
It doesn't change the fact that this is where all engine designers intend the engine to run. What evidence do you have that it is bad?
You keep using words like "punishing" and "thrashing". These are just words, not evidence.
But peak is generally in their “Red Box”.
Tell you what: Next time you take off around sea level on an ISA day with a big bore piston engine, lean the mixture so that you’re getting the maximum possible power out of the engine. (Hint: That’s a setting ROP.) And for good measure to perpetuate another OWT, pull the RPM back to 2,500. If you don’t believe you’re “punishing” and “thrashing” the engine at that setting, it won’t take long for you to see the evidence to the contrary.
Will you take up my offer to pay for your seat at the next APS in Australia?
(PS: You need to take care to include the unit of measurements in the numbers you quote. It’s 50F.)
Last edited by Lead Balloon; 4th Apr 2018 at 22:55.
Great. PM me when you make the booking, and I’ll arrange payment to APS.
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(PS: You need to take care to include the unit of measurements in the numbers you quote. It’s 50F.)
As I said, the surest way to cause detonation in my engine is to run it where the POH says to run it.
From first-hand observation of measurements taken from a piston aero engine in a test cell.
Indeed, those measurements indicate that many big bore piston engines run in a state of mild detonation at settings that are uncontroversial from any perspective.
Indeed, those measurements indicate that many big bore piston engines run in a state of mild detonation at settings that are uncontroversial from any perspective.
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What size bore ?
For the edrumergated there is a great difference between a opposed engine used in ga and the large radials used in a time since past. While they both suck push bang blow thats basically where it starts and finishes.
The airlines did not invent running lop btw. It was used by the millitary mostly to cross the pond to the UK for delivery. In fact there is a great book on it were they were running lop and had to go to rop to make it.
There are no free rides everthing has its costs.
For the edrumergated there is a great difference between a opposed engine used in ga and the large radials used in a time since past. While they both suck push bang blow thats basically where it starts and finishes.
The airlines did not invent running lop btw. It was used by the millitary mostly to cross the pond to the UK for delivery. In fact there is a great book on it were they were running lop and had to go to rop to make it.
There are no free rides everthing has its costs.
While they both suck push bang blow thats basically where it starts and finishes.
Or maybe the laws of chemistry and physics mean the fuel/air being sucked into a cylinder fitted to a radial engine combusts differently than if it’s being sucked into a cylinder fitted to a horizontally opposed engine. Maybe the compression is squashier or the spark sparkier? Hmmmm....But what happens when the aircraft to which the radial engine is fitted goes into a vertical climb or dive and the engine effectively becomes horizontally opposed? Does the fuel/air being sucked into the pistons ‘know’ to behave differently? Remarkable technology.
Walk us unedgumicated through it, Rod.
Page 180 in Fate is the Hunter makes reference to boffins getting the crews to operate at reduced RPM and MP so I imagine that operating LOP was part of it. EK Gann found that it was bollocks in practise, but then again what would he know.
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How about this. Why dont you tell us why the radial and the opposed egines are the same. Now im sure younknow why this is as your an expert at all things and done the aps course and then i will respond to your comments. So back to you. Let see what you come up with. Im not holding my breath while i wait but as you also believe that a rich mixture burns slower than a lean mixture i dont hold much faith in you getting much right but who knows you may supprise
Waiting in suspense
Waiting in suspense
Perhaps Lead Balloon is a complete idiot when it comes to his IO-520 engine management, Connedrod and andrewr?
But somehow, he manages to do a lot of GA flying and remarkably stays alive!
But somehow, he manages to do a lot of GA flying and remarkably stays alive!