A Little Gem from CASA Experts
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Where is Andrewr? He has gone missing since post 95 where I suggested he find out a bit more about how the 520s work so he can understand the problem and why gami injectors are an affordable solution because they don't involve rebuilding the induction system. Perhaps he has been busy with work or just possibly he took me seriously and found there is much to learn from sources other than rev heads in car engine shops.
Post 95 still stands.
Post 95 still stands.
While there is a problem with the inlet maniflolds thats not were the problem starts. The cylinder breathing is a problem foremost of crank angle.
May i sugest that some people that propagate their views dont even understand basic engine construction and operation. The flow of air into a n/a engine is crontroled by many variables starting at crank angle mainifold flows valve angles. By varying the flow of fuel is masking the problem the difference between a gami and normal old is extremely small. But just enough to make a difference.
These engines are low reving high tq engines.
Translation of lycoming: "Yes it works in theory and in the laboratory, but its not profitable for us to make it work in the field and anyway, pilots are ham fisted idiots who wouldnt operate it correctly."
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The IO550 referenced above does not "think" it is at seevel. It "knows " exactly where it is. The clue is in the density controller maintaining power output to the sea level power.
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Let’s see if I can guess this one.
My guess is that the end result of damage to the engine is: damage to the engine.
I think the strongest argument against LOP operations is that no engine operating ROP has ever failed or suffered damage during those operations.
My guess is that the end result of damage to the engine is: damage to the engine.
I think the strongest argument against LOP operations is that no engine operating ROP has ever failed or suffered damage during those operations.
Translation of lycoming: "Yes it works in theory and in the laboratory, but its not profitable for us to make it work in the field and anyway, pilots are ham fisted idiots who wouldnt operate it correctly."
That’s right. No engine operating ROP has ever failed or suffered damage during those operations.
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There are plenty of airports adjacent the ocean whose runway surface, in the context of engine performance, is not meaningfully higher than sea level.
Would you say that an airplane in the middle of it's take-off run at such an airport is operating or not operating?
That said, do you seriously not realize that sea-level ISA standard day is a common reference for aircraft performance, and more specifically engine power output? Take a look the Type Certificate Data Sheet for almost any piston engine. The Rated power is referenced to sea level.
Besides, what on earth is your point? The point LB was making with his rhetorical question is the same whether he'd used sea level, 1,000 ft, or 10,000 ft.
Last edited by A Squared; 12th Apr 2018 at 05:07.
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OK, going back and reading a few earlier posts I'd skipped over previously:
Not sure what your point is here. You seem to be trying to suggest that all those tolerances can stack up to throw your timing off even more. Not true. The internal timing of the magneto (e-gap or point gap) only determines where the spark fires at the optimum time in the field rotation, it has nothing to do with where that happens relative to the crankshaft rotation. That is determined solely by the magento-to-engine timing. (ie: rotating the magneto on the accessory case so that point opening happens at a certain crankshaft angle) If your magneto is timed so that the points open at 22 deg. BTDC, it really doesn't matter whether your e-gap is set at 13 degrees or 17 degrees, the spark still fires at 22 Deg. BTDC. The e-gap setting only determines the efficiency of the spark generation. (that's what the "e" in e-gap stands for; efficiency)
Jeeeez dude. Are you not reading anything? He told you how he knew. He Noted higher than normal CHT's on climbout, did an airborne mag check, noted a difference from one mag to the other, then when on the ground, checked the timing (as we later were told, using a Mag-rite electronic protractor set-up) and found one of his mags to have been set to 25 degrees BTDC.
FYI.
TCM IO520 engine - magnetoto engine timing 20 degrees BTC +/- 1 degree.
Bendix 1200 - E gap timing 15 degrees +/- 2 degrees
Bendix 1200 - points gap 0.016 +/- 0.003 thou.
Champion - RHB32E gap 0.016 - 0.021.
So one magneto can be 19 deg TDC, E gap 13 deg, point gap 0.013& spark plug gap 0.016.
The other mag 21 deg TDC, E gap 17 deg, point gap 0.019& plug gap 0.021.
TCM IO520 engine - magnetoto engine timing 20 degrees BTC +/- 1 degree.
Bendix 1200 - E gap timing 15 degrees +/- 2 degrees
Bendix 1200 - points gap 0.016 +/- 0.003 thou.
Champion - RHB32E gap 0.016 - 0.021.
So one magneto can be 19 deg TDC, E gap 13 deg, point gap 0.013& spark plug gap 0.016.
The other mag 21 deg TDC, E gap 17 deg, point gap 0.019& plug gap 0.021.
Jeeeez dude. Are you not reading anything? He told you how he knew. He Noted higher than normal CHT's on climbout, did an airborne mag check, noted a difference from one mag to the other, then when on the ground, checked the timing (as we later were told, using a Mag-rite electronic protractor set-up) and found one of his mags to have been set to 25 degrees BTDC.
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I think what he was saying is that he came back at sl mainifold px. Ie it’s turbo charged and was able to maintain sl performance till it reach critical alt.
As for engine damage once again you have shown your complete lack of knowledge on the subject. So how do you find tdc. A protractor type is as accurate as a digital. If you use a digital it must be calibrated btw.
As for engine damage once again you have shown your complete lack of knowledge on the subject. So how do you find tdc. A protractor type is as accurate as a digital. If you use a digital it must be calibrated btw.
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FFS, what is your fetish with demanding how to find TDC? It ain't rocket science. It's actually a butt-simple and fairly obvious procedure. Tell ya what, if I describe the procedure will you promise to STFU about asking how it's done? Promise?
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Can you point out those words of mine which you have misinterpreted as me saying *anything* about engine damage?
FFS, what is your fetish with demanding how to find TDC? It ain't rocket science. It's actually a butt-simple and fairly obvious procedure. Tell ya what, if I describe the procedure will you promise to STFU about asking how it's done? Promise?
FFS, what is your fetish with demanding how to find TDC? It ain't rocket science. It's actually a butt-simple and fairly obvious procedure. Tell ya what, if I describe the procedure will you promise to STFU about asking how it's done? Promise?
The only way to truly find it is to use a dial indicator. Anything else is has a degree of error. So when he Carey’s on and is unable to answer it’s just showing his lack of knowledge on this subject. I’m asking basic questions and he and others are unable to answer them
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Well, actually, it was 3 degrees, 25 degrees BTDC vs 22 degrees BTDC. Yeah, that's well outside of tolerance. There's errors inherent in every method of determining TDC, including with a dial indicator, but I'm pretty sure that the method with the "locator" screwed into the spark plug hole and the protractor on the spinner is accurate enough to detect a 3 degree error. It is, after all, the method that Teledyne Continental specifies in their MSB about magneto timing.
Last edited by A Squared; 12th Apr 2018 at 06:30.
Thread Starter
Folks,
At the risk of being flamed by Rod the Con(and recognizing, as at least some of you do, that any measurement has an error) finding top dead center by any measures that rely on the height of the piston at TDC, results can vary quite markedly.
Perhaps some of you should acquaint yourselves with common practice on high performance auto racing engines from the era before all timing being determined by precision electronics.
In short, you determine a crank position for a chosen distance of the piston from approx. TDC, say 1", you measure this distance with the piston rising from both sides of TDC, ie: Normal and reverse rotation. Then you halve that on your protractor fixed to the crank, that is the most accurate TDC I know how to measure, and far less prone to error than trying to pick the piston at the top of the stroke. If you have a nice big protractor (mine is an aluminium disk, suitably engraved, about 15" diameter) that should get you TDC +/- 1 degree.
Tootle pip!!
At the risk of being flamed by Rod the Con(and recognizing, as at least some of you do, that any measurement has an error) finding top dead center by any measures that rely on the height of the piston at TDC, results can vary quite markedly.
Perhaps some of you should acquaint yourselves with common practice on high performance auto racing engines from the era before all timing being determined by precision electronics.
In short, you determine a crank position for a chosen distance of the piston from approx. TDC, say 1", you measure this distance with the piston rising from both sides of TDC, ie: Normal and reverse rotation. Then you halve that on your protractor fixed to the crank, that is the most accurate TDC I know how to measure, and far less prone to error than trying to pick the piston at the top of the stroke. If you have a nice big protractor (mine is an aluminium disk, suitably engraved, about 15" diameter) that should get you TDC +/- 1 degree.
Tootle pip!!
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That's true. I wasn't gonna mention that, but now that you have, at the top of the stroke, the piston moves very little with fairly large changes in crankshaft angle. It makes it a challenge to figure crankshaft angle accurately, which is what you're really interested in.
Hmmm
I flew from Coffs to Syd at FL160 today with my Turbo IO-550 engine at sea level. Yep one of the high compression ones.
Had I ran my engine at 84% ROP I am sure I would be on the evening news.
I will not let an engineer touch my plane unless I am part of the process. Get it..My Plane!
AWOL in the FL's
I flew from Coffs to Syd at FL160 today with my Turbo IO-550 engine at sea level. Yep one of the high compression ones.
Had I ran my engine at 84% ROP I am sure I would be on the evening news.
I will not let an engineer touch my plane unless I am part of the process. Get it..My Plane!
AWOL in the FL's
That would make it a TIO-550!
Process is you tell me the fault, I fix it, you pay and you go.
If not just go.
And tell your mates, all of them.
That will save me a lot of time.
MY HANGAR - my rules.
An IO550 will not have a "Density Controller" that is a component fitted to a "T" engine.
Some may be all IO-550 engines have altitude compensating bellows.