![]() |
If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
Thread Tools | Display Modes |
#171
|
|||
|
|||
![]()
Larry Dighera wrote:
On Sat, 06 Oct 2007 11:40:55 GMT, Matt Whiting wrote in : I'm not aware of any real data on the subject http://www.lycoming.textron.com/supp...ces/SSP400.pdf Descent Plan ahead to make a smooth temperature transition between cruise and descent. Start descent early and allow airspeed to increase within aircraft limits. Maintain power as required and mixture setting. Cylinder head temperature change rate should not exceed 50 degree F per minute to avoid rapid shock cooling. Like I said, there is no data on the subject. Lots of opinions, but no data. The GAMI folks are some of the more data oriented out there and they have refuted several OWTs, even some that come from the engine manufacturers. Maybe you can point how to me the test data in an of the references you posted that shows multiple identical engines, some that were run only at steady RPM and some that were used for touch and goes all day, and the component measurements at tear-down. I didn't see this in anything you posted. Matt |
#172
|
|||
|
|||
![]()
Larry Dighera wrote:
On Sat, 06 Oct 2007 11:22:14 +0200, Thomas Borchert wrote in : Turns out, as Jay revealed so nicely, he himself is the problem. What saddens me is that this "community" does nothing about it if it's our oh-so-esteemed Brother Jay, but screams bloody murder when someone like MX does it. Usenet, indeed... Such a bias toward comrades is not unique to Usenet. I see the bias you mention as the result of at least two factors: a result of Mr. Honeck's "contribution" to GA, contrasted against Mr. Atkielski's maligning of GA (and indeed most other aspects of non-artificial aviation). Couple that with the social bonding that occurs among drinking buddies and EAA members, and it's easy to see how Mr. Honeck's frequent lack of insight and subjective opinion in lieu of empirical fact are overlooked and tolerated by a certain segment of the readership of the rec.aviation.piloting newsgroup. Really? Must be my ISP is missing posts as what I've seen is running almost unanimously contrary to Jay's opinion. Matt |
#173
|
|||
|
|||
![]()
Matt Whiting writes:
Really? Must be my ISP is missing posts as what I've seen is running almost unanimously contrary to Jay's opinion. In other words, you disagree. The tyranny of viewpoints. |
#174
|
|||
|
|||
![]()
Mxsmanic wrote in
: Thomas Borchert writes: Thanks. I was beginning to ask myself what my problem might be in communicating about this. Turns out, as Jay revealed so nicely, he himself is the problem. What saddens me is that this "community" does nothing about it if it's our oh-so-esteemed Brother Jay, but screams bloody murder when someone like MX does it. Usenet, indeed... Facts and reality rise above personal squabbles, You've never posted a fact in your life you didn't cut and paste. Betie |
#175
|
|||
|
|||
![]()
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 |
#176
|
|||
|
|||
![]()
Mxsmanic wrote in
: Jay Honeck writes: Ah, this is truly a rare alignment of the stars, to have all three of these guys present in one thread... My work here is done. I can achieve no higher goal. A useful suggestion from a very experienced user of USENET: Never take anything on USENET personally. Or, if you posted, it, as fact. Bertie |
#177
|
|||
|
|||
![]()
Mxsmanic wrote in
: Matt Whiting writes: Really? Must be my ISP is missing posts as what I've seen is running almost unanimously contrary to Jay's opinion. In other words, you disagree. The tyranny of viewpoints. God I love usenet. Bertie |
#178
|
|||
|
|||
![]() "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 |
#179
|
|||
|
|||
![]()
Ah, this is truly a rare alignment of the stars, to have all three of
these guys present in one thread... My work here is done. I can achieve no higher goal. A useful suggestion from a very experienced user of USENET: Never take anything on USENET personally. I never do. Been here a long time, and I ain't goin' anywhere... Larry, Thomas, and, yes, even you, Anthony, would receive nothing but hospitality (and a cold one or three) at my dinner table, should you ever find your way to Iowa. Under all the bluster and hard blowing here, I have yet to meet anyone who hasn't been a perfect gentleman, no matter how crazy they may seem here. -- Jay Honeck Iowa City, IA Pathfinder N56993 www.AlexisParkInn.com "Your Aviation Destination" |
#180
|
|||
|
|||
![]()
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" |
Thread Tools | |
Display Modes | |
|
|
![]() |
||||
Thread | Thread Starter | Forum | Replies | Last Post |
Scared of mid-airs | Frode Berg | Piloting | 355 | August 20th 06 05:27 PM |
UBL wants a truce - he's scared of the CIA UAV | John Doe | Aviation Marketplace | 1 | January 19th 06 08:58 PM |
The kids are scared, was Saddam evacuated | D. Strang | Military Aviation | 0 | April 7th 04 10:36 PM |
Scared and trigger-happy | John Galt | Military Aviation | 5 | January 31st 04 12:11 AM |