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Posted
5 hours ago, Brandt said:

I’ve gone through one cylinder in 800 hours and that was due to a bad ring. 

Since you're at 800 hours, you should change all six exhaust rotocoils right now. 

Posted

When they recently lapped my two oldest cylinders' (1450+ hrs, original) exhaust valves, and ring flushed, they also replaced one of the rotocoils. I asked about prophylactically replacing others, but was advised to keep watching. BTW this fixed the compressions and greatly decreased oil consumption over the next 25 hrs or so. 

Recently, a cyclic oscillation with a 30 sec period and about 25F magnitude developed on one of these, with the replaced rotocoil. It became intermittent the next flight but Savvy were concerned about a sticking exhaust valve (maybe incomplete lapping). Subsequent borescope didn't show anything wrong (original abnormal valve heat pattern had disappeared), so advice was to keep watching. 

I think there is a fundamental question of how much to do prospectively vs. "on condition". I brought up just overhauling both of these cylinders pre-emptively, as I have 400-600hrs to go before considering overhaul "based on the #s", and maybe this would be insurance... (I had been warned in the abstract I might need to replace these cylinders at some point). However, two experienced, thoughtful A&Ps after reviewing data and scope pictures were essentially saying it was a difficult question at the current juncture, and keep an eye on them every 50 hrs or otherwise on condition was reasonable. 

DK

Posted
3 hours ago, Mcstealth said:

"Comfort" is such a subjective conversation. One man's apple is another man's orange. I would not go as far to say that the Mooney is the most uncomfortable. I know I love long distance driving in my low slung, legs forward seated sports car. I know I loath driving the same long distances in a Surburban. There are a multitude of articles about the long distance prowess of different Mooney models and nary a mention about the "uncomfortableness" of their respective cockpits. 

Again, apples to oranges, and, to each their own. 

I agree with you about the position, and the subjectivity of what is comfortable.
I happen to love the semi supine position and the Mooney is by a wide margin, (nothing is even a close second really) the most comfortable seating of any plane I have flown. 
But if you prefer fully erect chair position you won’t like it very much. 
I love the Aerostar, but I miss having my legs stretched out. 

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Posted
On 8/12/2024 at 3:13 PM, dkkim73 said:

However, two experienced, thoughtful A&Ps after reviewing data and scope pictures were essentially saying it was a difficult question at the current juncture, and keep an eye on them every 50 hrs or otherwise on condition was reasonable. 

I think this is the genesis of 80% of cylinder replacements.
Many/most A&P’s prefer to “change parts” until the problem goes away, rather than diagnose the actual cause, or do things like lapping or ring flushes to ameliorate the issue.  
I don’t mean this to denigrate them, it’s probably just the way they were trained, and maybe it’s an easier way to justify the time and expense.  
But after all of my experiences, I think most of the cylinder replacements we see and hear about are not necessary, and this created a poorly embellished reputation. 

Posted
1 hour ago, dkkim73 said:

... my two oldest cylinders' (1450+ hrs, original) ...

To be clear, I did buy the plane with a higher-time engine, and these cylinders are original. The internet would have you believe they should have departed the aircraft already, either quietly in a shop, or loudly frog-marched out by the laws of physics over the mountains of Idaho. 

 

On the spectrum of things, this seems like better performance and life. Other cylinders have been replaced, and I don't know how the plane was flown before I got it. If these were needing replaced it wouldn't seem like an unreasonable lifetime (?)

Just realize the whole cylinder-management discussion is a matter of significantly different opinions and evolving practice (I think you mentioned you read Mike Busch... my take on his position is that cylinders should not be replaced too readily, but are nonetheless a "consumable item"... it's like some kind of Zen koan).

And again, many of the planes mentioned use Conti's, so not a differentiator. Unless the thread is pushing you toward a Bravo ;)

The comment about "if it's not one thing it's another" is sage. We all wish there were a magic maneuver that would obviate the need for maintenance and surveillance, but as the reliability-centered maintenance analysis indicates there isn't really a magic bullet as replacing everything might shuffle new jokers into the deck. 

  • Like 1
Posted
7 hours ago, 1980Mooney said:

I am not sure where you are getting that notion. Cirrus sales of SEP are more than double Textron. 

Is this correct year over year?

The last time I looked at this was a few years back when we had a sales thread here on MS, and Textron vs Cirrus was 300ish for each. I think it was 306 vs 347, with the significant edge to Cirrus. 

I certainly don’t perceive Cirrus as outselling Textron 2:1. I think of them as being very close on annual SEP sales.

Anyway, if Cirrus is reliably selling 2:1 year over year, then I’ll withdraw the comment. I may have seen the aberration and assumed it was the average. 

Posted
4 hours ago, Grant_Waite said:

Why does everyone seem to use continentals if they have so many issues compared to lycomings? 

They come in a lot of popular airplanes, including Bonanzas/Barons, various Mooneys, Cirrus, various Cessnas (182, 210, 310, etc.), etc., etc.  There are a lot of them out there.   Some people do shop specifically to get an airplane with a Lycoming, and there are variants of Beechcraft, Mooney, Cessna, etc., that have them as well.

Posted
2 hours ago, toto said:

Is this correct year over year?

The last time I looked at this was a few years back when we had a sales thread here on MS, and Textron vs Cirrus was 300ish for each. I think it was 306 vs 347, with the significant edge to Cirrus. 

I certainly don’t perceive Cirrus as outselling Textron 2:1. I think of them as being very close on annual SEP sales.

Anyway, if Cirrus is reliably selling 2:1 year over year, then I’ll withdraw the comment. I may have seen the aberration and assumed it was the average. 

https://generalaviationnews.com/2024/04/07/10-best-selling-piston-airplanes-in-2023/

https://generalaviationnews.com/2023/03/12/10-best-selling-piston-airplanes-in-2022/

https://generalaviationnews.com/2022/02/28/10-best-selling-piston-airplanes-in-2021/

https://generalaviationnews.com/2021/03/11/top-10-best-selling-piston-airplanes-in-2020/

 

https://www.avbuyer.com/articles/ga-buyer-europe/how-many-piston-aircraft-deliveries-for-2019-so-far-112542

Posted
On 8/12/2024 at 4:15 PM, dkkim73 said:

The internet would have you believe they should have departed the aircraft already, either quietly in a shop, or loudly frog-marched out by the laws of physics over the mountains of Idaho. 

Ha!  Physics is a bi^ch.

Posted
On 8/12/2024 at 3:19 PM, Grant_Waite said:

Why does everyone seem to use continentals if they have so many issues compared to lycomings? 

My theory (that will be $0.02 please) is that they are easier to abuse--especially turbocharged.

Posted
My theory (that will be $0.02 please) is that they are easier to abuse--especially turbocharged.

Grant seems to imply that new aircraft buyers can chose between a Continental and a Lycoming.
Exactly how many Lycoming powered aircraft are there in the class of Mooney’s - None. The pressurized Malibu/M350 was the only one that comes to mind with a 350 HP TIO-540 and it’s not really in the same class as the other singles.
Why? my bet is because the Lycoming doesn’t pencil out anywhere near as good at the Continentals for range and endurance because they are excellent running LOP; not so much on the Lycoming.

But it doesn’t matter what engine manufacturer you’re flying behind. If you run them like the a factory demo pilot shows it off at max cruise and 50F ROP, those cylinders are going to only go mid-time at best. 50F ROP may provide the best power/speed but it’s the worst place to operate your engine wrt to longevity. The smart pilot with some understanding of combustion science more concerned about longevity will operate at or below 65% and LOP, and also learn about benefits of lower RPM. But 65% LOP is a gentler kinder power setting.

Of course some are just willing to make the trade offs to go fast and it’s a personal choice.

BTW, I should add that one aircraft manufacturer we all know does give you a choice in which power plant it comes with - Cirrus. Not long ago you had your choice of two different turbo’s and 1 NA that are all Continentals. They have since dropped the TAT TN, so now 2 options.

Sent from my iPhone using Tapatalk
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Posted
24 minutes ago, kortopates said:


Grant seems to imply that new aircraft buyers can chose between a Continental and a Lycoming.
Exactly how many Lycoming powered aircraft are there in the class of Mooney’s - None. The pressurized Malibu/M350 was the only one that comes to mind with a 350 HP TIO-540 and it’s not really in the same class as the other singles.
Why? my bet is because the Lycoming doesn’t pencil out anywhere near as good at the Continentals for range and endurance because they are excellent running LOP; not so much on the Lycoming.

But it doesn’t matter what engine manufacturer you’re flying behind. If you run them like the a factory demo pilot shows it off at max cruise and 50F ROP, those cylinders are going to only go mid-time at best. 50F ROP may provide the best power/speed but it’s the worst place to operate your engine wrt to longevity. The smart pilot with some understanding of combustion science more concerned about longevity will operate at or below 65% and LOP, and also learn about benefits of lower RPM. But 65% LOP is a gentler kinder power setting.

Of course some are just willing to make the trade offs to go fast and it’s a personal choice.


Sent from my iPhone using Tapatalk

to quote @Fly Boomer

"Ha!  Physics is a bi^ch."

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