Engine Red line as a result of Speed Vs Power

Tarheelpilot said:
What you have said and the way you have framed your statements is inappropriate for the conversation being held in this thread.
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Just passing along what I know to be true about Lycomings. I can see how those who have no familiarity with the issue may think what I say is inappropriate.
 
RoscoeT said:
I get it, you know zilch about aerobatics, its history, Lycoming engines, or aerobatic pilots, and therefore consider my ONE specific point about a Lycoming not needing a dang inspection because it turned 2900 RPM to be a "hazardous attitude". These are not anecdotal "stories". It's SOP in this world. The engines don't blow up. We are not hazardous. The FAA does not give a single damn about the RPM we run. Fact. Carry on.
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The thing you're leaving out is many of those guys rebuild their engines at a small fraction of published TBO. Now, whether that's because of RPM, jacked up compression, etc., there is no telling, but the mission and the risk factor are vastly different between a hard acro airplane and a Tiger where the owner is trying to squeeze many years and many hours out of the engine.
 
RoscoeT said:
Just passing along what I know to be true about Lycomings. I can see how those who have no familiarity with the issue may think what I say is inappropriate.
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I'm genuinely curious. What is the limit then? Just how fast can you spin your engine before you hurt a piston, rod or spring? Does this apply to all lycomings or just certain models?
 
kyleb said:
The thing you're leaving out is many of those guys rebuild their engines at a small fraction of published TBO. Now, whether that's because of RPM, jacked up compression, etc., there is no telling, but the mission and the risk factor are vastly different between a hard acro airplane and a Tiger where the owner is trying to squeeze many years and many hours out of the engine.
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Nope. Where am I equating the two? Where am I advocating GA pilots deliberately and regularly "overspeed" their engines? Where do I indicate that there is any point for doing this in normal GA planes? If anyone who wants to keep this up will just re-read the thread, all I'm saying is that pilots don't need to worry about inspecting their damn engine if they ever happen to go 10% or so over, for longer than "momentary". I'm not talking about operating this RPM as SOP. I say that not because it's so risky, but because there's no point for non-acro planes.
 
James_Dean said:
I'm genuinely curious. What is the limit then? Just how fast can you spin your engine before you hurt a piston, rod or spring? Does this apply to all lycomings or just certain models?
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If you don't want an engine part to fail, don't ever crank the engine up. Most engine failures occur while operating in the "normal" RPM range. You are asking an overly simplistic question.
 
RoscoeT said:
Just passing along what I know to be true about Lycomings. I can see how those who have no familiarity with the issue may think what I say is inappropriate.
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I know of what you say. It's inappropriate to share that level of knowledge with a guy that doesn't understand how his cirrus magically maintains rpm. You'll confuse the issue at hand and will not provide him the answer he needs.
 
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Nah.... not worth it. I'll sit this out.
 
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kyleb said:
The thing you're leaving out is many of those guys rebuild their engines at a small fraction of published TBO. Now, whether that's because of RPM, jacked up compression, etc., there is no telling,
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Partly due to fast snaps, hard gyro, etc. Really hard on the lower end. Partly due to running continuously at 100% power (or well over the original rated 100% - a lot of improved engines out there) instead of backing down to a nice easy 70%. Partly do to intermittent oil pressure - even an inverted system burps a bit during the zero G transitions. It all adds up.
 
Tarheelpilot said:
I know of what you say. It's inappropriate to share that level of knowledge with a guy that doesn't understand how his cirrus magically maintains rpm. You'll confuse the issue at hand and will not provide him the answer he needs.
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Pretty sure the OP Cirrus "guy" knows how his engine maintains RPMs and that he got the answer he needs.
 
RoscoeT said:
Pretty sure the OP Cirrus "guy" knows how his engine maintains RPMs and that he got the answer he needs.
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I guess we will just have to agree to disagree. I do understand what you are talking about. From personal experience in both piston and turbine engine aircraft.

I still think it was the wrong place to bring it up.

Tailwinds
 
I know several guys who have STOL props that make very near redline revs when static. That's how you win STOL contests. Most of those are family airplanes. And then there's the Exp guys and nitrous injection. Those motors don't know what redline means.
 
yeah so I know how the Cirrus works but I have worked hard to establish myself as someone that doesn't so lifting the curtain is going to mess up my life's work. That was the foundation for me using the term "magic". I know its not magic.

I just needed to frame the question which led me to comparing my new to me plane which uses no "magic"

The point was that in the plane that has a constant speed prop which is adjusted for me, I have not had to deal with RPM fluctuations as a result of changes in pitch.

However in my new little Grumman, I am all throw back Thursday into my 172 training where pitching this way and that cause the RPMS to fluctuate.


Ultimately while I understand both aircraft and why they do what they do, I wasn't sure if I killed the mags and mixture in a not so magic plane and dove to the point of busting red line, is that a concern. I believe from this thread that redline is not a cap on the amount of explosions per minute that occur in the engine but actual rotations no matter what the cause.
 
Maybe the bigger take is that if you pull the throttle and point the nose down you won't overspeed your engine. Some of us, both fixed and CS prop guys, use closed throttle as a speed brake.
 
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