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#1
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Jay Honeck wrote:
I do believe this thread proves the old Usenet adage that "anyone will argue anything". For you to be questioning the rather obvious fact that high-power/low-power engine operations are harder on an aircraft than steady-state engine operations illustrates a remarkable, um, quality. Jay, this simply isn't an "obvious fact" and I'm not convinced it is a fact at all. You have provided one mechanic who thinks your way and several of us have provided mechanics who disagree. This is hardly the scenario that would surround an "obvious" fact. Matt |
#2
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I do believe this thread proves the old Usenet adage that "anyone will
argue anything". For you to be questioning the rather obvious fact that high-power/low-power engine operations are harder on an aircraft than steady-state engine operations illustrates a remarkable, um, quality. Jay, this simply isn't an "obvious fact" and I'm not convinced it is a fact at all. You have provided one mechanic who thinks your way and several of us have provided mechanics who disagree. This is hardly the scenario that would surround an "obvious" fact. I am apparently speaking a foreign language here, because I'm having a hard time comprehending how normally intelligent people can argue this point. Let's see if I can 'splain myself. 1. High power operation of an engine puts increased strain on EVERYTHING. Seals, rods, gears, accessories. You name it, high power operation is harder on your engine than low power operation. 2. Going from low to high power abruptly (and that, remember, is the crux of this issue; I don't think anyone is arguing that gradual/ gentle application is terrible for your engine -- although it WILL wear it out faster) puts sudden, abrupt pressue on those aforementioned seals, rods, gears, pistons, cylinders, accessories. This is what is known as "BAD", in my world. 3. Your engine has a certain number of revolutions in it before it reaches TBO. Might be a million, might be a billion -- I don't know. Whatever that number, if you run at higher RPMs, you will reach that finite limit sooner. Stuff run at high RPM wears out quicker. And, most importantly to this thread, engines rammed from 900 RPM to full power, and back, over and over, are going to wear out sooner. Same with props, automobiles, lawn mowers, motorcycles, blenders, chain saws, snow blowers, and virtually any other mechanical device you can name. -- Jay Honeck Iowa City, IA Pathfinder N56993 www.AlexisParkInn.com "Your Aviation Destination" |
#3
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Jay Honeck wrote:
I do believe this thread proves the old Usenet adage that "anyone will argue anything". For you to be questioning the rather obvious fact that high-power/low-power engine operations are harder on an aircraft than steady-state engine operations illustrates a remarkable, um, quality. Jay, this simply isn't an "obvious fact" and I'm not convinced it is a fact at all. You have provided one mechanic who thinks your way and several of us have provided mechanics who disagree. This is hardly the scenario that would surround an "obvious" fact. I am apparently speaking a foreign language here, because I'm having a hard time comprehending how normally intelligent people can argue this point. Let's see if I can 'splain myself. 1. High power operation of an engine puts increased strain on EVERYTHING. Seals, rods, gears, accessories. You name it, high power operation is harder on your engine than low power operation. Stress (and the strain it induces) isn't a problem in a well-designed engine or any other structure. As long as the strain remains well below the elastic limit, virtually no harm is done. I say virtually, as depending on the material fatigue issues may arise if the stress is high enough and the cycles large enough. As long as the oil film isn't compromised, the higher stress does NOT cause any additional wear. Why can't you understand this? And the seals and accessories are not much aware of how much power the engine is producing. They are much more concerned with RPM and the RPM isn't a direct measure of power output. 2. Going from low to high power abruptly (and that, remember, is the crux of this issue; I don't think anyone is arguing that gradual/ gentle application is terrible for your engine -- although it WILL wear it out faster) puts sudden, abrupt pressue on those aforementioned seals, rods, gears, pistons, cylinders, accessories. This is what is known as "BAD", in my world. Again, unless you are exceeding the limits of the materials, the metal doesn't much care how fast you apply the load. Jay, you need to understand that not all things yield to intuition. Many material properties and engineering principles are not intuitive. 3. Your engine has a certain number of revolutions in it before it reaches TBO. Might be a million, might be a billion -- I don't know. Whatever that number, if you run at higher RPMs, you will reach that finite limit sooner. Stuff run at high RPM wears out quicker. Do you have even one shred of data to back up this claim? I believe that NOT running an engine is THE fastest way to kill it. Starting it often is the next fastest way. And running it is the way to make it last longest. I doubt that the average number of revolutions per hour is much higher for T&G practice in the pattern as it is for cruise. Many folks fun at lower than cruise RPM in the pattern and the higher RPM during climb-out is offset to a large degree by the lower RPM during descent. RPM alone does not wear out an engine. And, most importantly to this thread, engines rammed from 900 RPM to full power, and back, over and over, are going to wear out sooner. Same with props, automobiles, lawn mowers, motorcycles, blenders, chain saws, snow blowers, and virtually any other mechanical device you can name. I don't believe that to be true and you have shown absolutely no data to substantiate that. I worked as a logger for 5 years and we used Stihl brand saws almost exclusively. They ran at 6 - 8,000 at full tilt and were started and stopped dozens of times each day and went from idle to full throttle to idle hundreds to thousands of times each day (several times limbing just one tree). The engines were simply bullet-proof. We literally never wore out a single Stihl engine. Something else always happened to the saw before the engine wore out. We ran these probably 1,500 to 2,000 hours per year as we worked 6 day weeks and often 10 hour days. Jay, I appreciate that you are saying what you believe to be correct based on your intuition, but I don't believe your intuition is correct in this case. The skidders, saws, and trucks that we ran the hardest always lasted the longest. We had one skidder that the operator ran more sedately as he thought it would make it last longer (he felt as you do about engines). It didn't make 3,000 hours (not much for a Detroit Diesel). When we tore down the engine, the transfer ports were half closed with carbon. When the engine shop saw it the reason they said the engine had to be rebuilt prematurely was that it wasn't operated at FULL THROTTLE as Detroit Diesel intended it to be operated. This caused it to run too cool and build up carbon. Matt |
#4
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![]() "Jay Honeck" wrote: Jay, this simply isn't an "obvious fact" and I'm not convinced it is a fact at all. You have provided one mechanic who thinks your way and several of us have provided mechanics who disagree. This is hardly the scenario that would surround an "obvious" fact. I am apparently speaking a foreign language here, because I'm having a hard time comprehending how normally intelligent people can argue this point. Let's see if I can 'splain myself. [snip assertions totally devoid of supporting evidence] Jay, old sport, I fear the problem is that you are *hearing* a foreign language. -- Dan T-182T at BFM |
#5
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Jay, old sport, I fear the problem is that you are *hearing* a foreign
language. Whatever. If you guys don't believe that beating an engine won't kill it quicker than babying it, because I lack "evidence", there's not much else I can say but "To each, his own." I will continue to fly my engine carefully and gently, nonetheless. -- Jay Honeck Iowa City, IA Pathfinder N56993 www.AlexisParkInn.com "Your Aviation Destination" |
#6
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![]() "Jay Honeck" wrote in message ups.com... Jay, old sport, I fear the problem is that you are *hearing* a foreign language. Whatever. If you guys don't believe that beating an engine won't kill it quicker than babying it, because I lack "evidence", there's not much else I can say but "To each, his own." I will continue to fly my engine carefully and gently, nonetheless. ************************************ I think you may be starting to get defensive, now. NOBODY here would think that an engine that is getting beaten will last as long as an engine running at constant output. The debate is whether running from idle, up to full power (gently) often will be worse on it than constant output. You and your mechanic have an opinion on the subject, and that is your right. I (and others) just don't agree that frequent power changes (done correctly) are significantly detrimental to the life of your engine, and no studies or numbers have been offered on either side to prove the case, either way. Beat an engine, no contest. Beyond that, it all comes down to opinion. That is all it could be, at this point. -- Jim in NC |
#7
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Jay Honeck wrote:
Jay, old sport, I fear the problem is that you are *hearing* a foreign language. Whatever. If you guys don't believe that beating an engine won't kill it quicker than babying it, because I lack "evidence", there's not much else I can say but "To each, his own." I will continue to fly my engine carefully and gently, nonetheless. And I'll continue to run mine as suggested by the service manager at the BMW shop when I bought my 1200LT ... "run it like you stole it." He said that BMW engines that weren't run hard right from the get-go tended not to seat the rings well and then always had oil consumption issues. So far, at nearly 4,000 miles, so good! The K engine really sings above 6 grand! Matt |
#8
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And I'll continue to run mine as suggested by the service manager at the
BMW shop when I bought my 1200LT ... "run it like you stole it." He said that BMW engines that weren't run hard right from the get-go tended not to seat the rings well and then always had oil consumption issues. So far, at nearly 4,000 miles, so good! The K engine really sings above 6 grand! With a motorcycle engine that is nearly disposable (and easily/cheaply repairable) I agree 100%. Goose that hog till it squeals. Besides, what's the worst thing that can happen if you blow it up? With my aircraft engine, no way. Not only is my butt hanging suspended two miles in the air, but the engine itself is currently valued at nearly $30K. For that kind of money I will do things gently, carefully, and by the book. -- Jay Honeck Iowa City, IA Pathfinder N56993 www.AlexisParkInn.com "Your Aviation Destination" |
#9
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Jay Honeck wrote:
And I'll continue to run mine as suggested by the service manager at the BMW shop when I bought my 1200LT ... "run it like you stole it." He said that BMW engines that weren't run hard right from the get-go tended not to seat the rings well and then always had oil consumption issues. So far, at nearly 4,000 miles, so good! The K engine really sings above 6 grand! With a motorcycle engine that is nearly disposable (and easily/cheaply repairable) I agree 100%. Goose that hog till it squeals. Besides, what's the worst thing that can happen if you blow it up? With my aircraft engine, no way. Not only is my butt hanging suspended two miles in the air, but the engine itself is currently valued at nearly $30K. For that kind of money I will do things gently, carefully, and by the book. Does Lycoming tell you not to practice emergency landings? I hadn't seen that before. If believing a myth gives you comfort, then by all means. :-) Matt |
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