Piston engine reliability (questions for high time pilots and mechanics)

Electric said:
So, for LOP - 300 - 380F is a good range, ROP - 390F + correct?
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LOP they will fall where they fall, keep the CHTs below redline and you're good. The main hazard with high CHT (above 420 or so) and ROP operations is the increased risk of detonation. It's detonation that will blow holes in your pistons. The other issue with high temp and high ICPs, especially with chromed and other over bored cylinders is the varied rate of expansion between aluminum and steel at the Acme thread interface between the head and the cylinder, you'll develop cracks and even blow the head clean off if you don't catch it in time. Again, LOP operations keep these factors in check by reducing both CHT and ICP.
 
I've been an engine guy since I was a kid, and when I got to airplanes at first I couldn't understand why I was being told to operate engines in such an inefficient destructive manner especially when I had a control to fine tune the mixture at my hand.
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The rich mixture settings recommended by engine and airframe manufacturers are liability driven, and written for the lowest common denominator.

Aircraft flight manuals and pilot operating handbooks are dumbed-down publications that to some degree make an effort to idiot-proof the product against the common household aviator.
 
DouglasBader said:
The rich mixture settings recommended by engine and airframe manufacturers are liability driven, and written for the lowest common denominator.

Aircraft flight manuals and pilot operating handbooks are dumbed-down publications that to some degree make an effort to idiot-proof the product against the common household aviator.
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I was pleasantly surprised that the POH for the Mooney Ovation I'm helping to sell recommends lean of peak.

I'm happier still to be getting 175 knots on 12 gph. :D
 
Henning said:
Mmmmm, the one in you sigfile?:dunno:
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Oh, THAT.

Believe me, I would if I could... But the insurance company says no, and finagling the $$$ when we just bought another new airplane would be somewhat difficult.

I am, however, starting to look at keeping it in a partnership here.
 
Henning....Can I assume this refers to the Lindbergh doctrine of defense? or is there a Lindbergh doctrine of engine management/fuel mixture that i dont know about???
Henning said:
the history of it from the war, the whole Lindbergh Doctrine ....
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flyingcheesehead said:
Oh, THAT.

Believe me, I would if I could... But the insurance company says no, and finagling the $$$ when we just bought another new airplane would be somewhat difficult.

I am, however, starting to look at keeping it in a partnership here.
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Dude, that's fourteen and a half and a chunk NMPG, that means if you back off another 10kts lean you can get near 17! That's impressive.

When Continental releases the Diesel you'll be able to get 21 or 22 running it on algae oil that you can farm yourself in any setting in perpetuity. There are already accepted and attainable Jet A compatible algae fuels.
 
genetk44 said:
Henning....Can I assume this refers to the Lindbergh doctrine of defense? or is there a Lindbergh doctrine of engine management/fuel mixture that i dont know about???
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Yep, engine/fuel. You run the lowest rpm and highest manifold pressure combination to attain your desired speed and lean it out to maximize your range. He went and visited the Flying Tigers in Burma teaching them this technique which doubled their operating range.
 
Thank you!


Henning said:
Yep, engine/fuel. You run the lowest rpm and highest manifold pressure combination to attain your desired speed and lean it out to maximize your range. He went and visited the Flying Tigers in Burma teaching them this technique which doubled their operating range.
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Henning said:
Dude, that's fourteen and a half and a chunk NMPG, that means if you back off another 10kts lean you can get near 17! That's impressive.

When Continental releases the Diesel you'll be able to get 21 or 22 running it on algae oil that you can farm yourself in any setting in perpetuity. There are already accepted and attainable Jet A compatible algae fuels.
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Assuming there are no winds (because those destroy me) I get 21 nautical miles per gallon in the Flybaby. My F150 on the other hand gets about 11.
 
jesse said:
Assuming there are no winds (because those destroy me) I get 21 nautical miles per gallon in the Flybaby. My F150 on the other hand gets about 11.
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To make a fair comparison, your Flybaby has the load and speed capability of an 80cc scooter getting 210mpg...;)
 
We just lost our 2nd Turbomeca helicopter engine, the first at 270tt and the second at 930tt. Certain turbines are NOT more reliable. Thank God it's a twin.

I own, maintain and fly a 177RG powered by a thundering Lyc 200HP angle valve 4 cylinder. Yes, the prospect of failure frightens me.

I often ask for pattern or box climbs right over the airport. I then fly my plan which always takes me over the airports, and at the highest practical altitude (which ain't much in a heavily loaded Thunder Cardinal)

Flying South out of Sav, GA I don't leave the airport until I'm at 5500. The swamp does not look good to me.

Does this make me safer? dunno. But I certainly plan to have an "out" if my engine quits.
 
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cujet said:
We just lost our 2nd Turbomeca helicopter engine, the first at 270tt and the second at 930tt. Certain turbines are NOT more reliable. Thank God it's a twin.

I own, maintain and fly a 177RG powered by a thundering Lyc 200HP angle valve 4 cylinder. Yes, the prospect of failure frightens me.

I often ask for pattern or box climbs right over the airport. I then fly my plan which always takes me over the airports, and at the highest practical altitude (which ain't much in a heavily loaded Thunder Cardinal)

Flying South out of Sav, GA I don't leave the airport until I'm at 5500. The swamp does not look good to me.

Does this make me safer? dunno. But I certainly plan to have an "out" if my engine quits.
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With that flight profile you'd be cheaper flying my 310.
 
Electric said:
What aircraft can possibly do this? RV?
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Mooney Ovation. I run it at about 22 squared lean of peak, and get 165-175 KTAS depending on altitude, and it always ends up being right around 12gph when it's leaned out unless I'm too high to pull 22" MP.

I plan on 13gph total just to account for the climb - It starts out at 25gph on the takeoff roll, and is usually still burning 18gph at the top of the climb (16.5ish yesterday when I took it up to 16,000) but it'll climb 800-1000 fpm at 120 KIAS.

It belonged to my late uncle and is thus for sale, if you're interested. :yes:
 
For laughs I'll post my numbers, in the Apache for slow travel and minimizing fuel burn I run 23" 2000RPM as lean as she'll go (which is right about at the idle/cut-off) burning 9.5GPH for 120kts. I effectively have a 172 that happens to have an extra engine and retractable gear.
 
2,000 hours, comes out to about 3,400 hours of engine run time. Almost all in piston twins. About 900 hours of engine run time with engines past TBO.

Never had a failure.

Piston engines are nowhere near as reliable as they could be. The efficiency is pretty close (although could be improved - and NOT with a FADEC), but the reliability can be improved. The reason that it has not improved is because the demand isn't there.

Sure, people want their engines to be more reliable. They aren't willing to pay for it, though. With turbine engines, part of the money you're paying goes into investing back into the engines to produce new engines, make improvements to existing ones, etc. With piston engines, the profit margin isn't there for reinvestment into the company, mainly due to litigation issues. So you have a vicious cycle: people complain about reliability, but also complain that they can't afford to pay any more for the engines. The companies can't sell the engines at a higher price, meaning that they can't reinvest money into trying to take cost out and improve reliability and performance.

We've seen a couple notable improvements over the years, mainly crankcase improvements, some crankshaft improvements, and also some cylinder improvements. Things can get a lot better, but I don't see it happening anytime soon.
 
The more you fly does not indicate that your odds of an engine failure are increasing, all more time flying will do is increase your odds of surviving should it happen to you.

There is inherent risk in almost everything we do, even drinking a glass of tap water from your kitchen sink. You can get mugged while walking to your car. There are all sorts of things that can go awry in our lives, but for the most part, we don't even think about them, we just live our lives.

Flying an airplane is part of that living our lives thing. It is good to train for such situations, such as engine out landings and such, that is called being pro-active, but to worry about things that have not, and probably will not happen, is kind of silly.

Train as best you can for the unknown, but in the meantime, live your life to the fullest. It does not last all that long anyway.

-John
 
cujet said:
We just lost our 2nd Turbomeca helicopter engine, the first at 270tt and the second at 930tt. Certain turbines are NOT more reliable. Thank God it's a twin.

I own, maintain and fly a 177RG powered by a thundering Lyc 200HP angle valve 4 cylinder. Yes, the prospect of failure frightens me.

I often ask for pattern or box climbs right over the airport. I then fly my plan which always takes me over the airports, and at the highest practical altitude (which ain't much in a heavily loaded Thunder Cardinal)

Flying South out of Sav, GA I don't leave the airport until I'm at 5500. The swamp does not look good to me.

Does this make me safer? dunno. But I certainly plan to have an "out" if my engine quits.
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Another "thinking" aviator....:yes:

If I have anyone aboard who is not an aviator known to me, or is not a beneficiary of my will trust, we NEVER leave our home drone at over 4,000 lbs. At that weight I can get it over the apartments at the north end, if I have to, OEI.

...flies a "thunder double Cardinal" AKA Seneca.
 
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kgruber said:
Pilots are VASTLY more likely to be killed in an airplane than a car. Of the people I have known, only one has been killed in a car. I remember at least 30 pilots, who I have met and talked with, who were killed in airplanes.

That's why pilots read NTSB reports.
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I disagree with this, but whatever. I also think that if you have a higher number of hours you have probably learned a lot of lessons on how not to die in an airplane. I have friends with anywhere from 6000 (5000 flying freight in twins) to 15000 and they're not dead :dunno:
Mafoo said:
The number of GA deaths per million flight hours, is 22.43.

This means once you have 2000 flight hours, your odds of dying are. 4.5% (this incudes pilot error as well).

If we asume that 2/3 of those are pilot error, we are down to 3%

I am 43 years old. My guess is it will take me 20 years to get to 2,000 hours. So 3% is only 6 times higher then my odds of dying from natural causes in that time frame anyway.

I like those odds :)
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You also need to remember that sometimes there is 1 person in the plane, sometimes there are 7. So those numbers are gonna be skewed...


And FWIW my Skylane RG gets better fuel milage and comparable fuel costs on >400nm trips. Jeep Commander FTW?
 
Z06_Mir said:
I disagree with this, but whatever. I also think that if you have a higher number of hours you have probably learned a lot of lessons on how not to die in an airplane. I have friends with anywhere from 6000 (5000 flying freight in twins) to 15000 and they're not dead ?
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You clearly don't, and haven't, met that many pilots.
 
kgruber said:
You clearly don't, and haven't, met that many pilots.
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Oh really? I worked line for 5 years in two different locations, both my parents were pilots, their friends were pilots. Now I'm a pilot, making my own pilot friends (which I have several of, BTW). I guess meeting 20+ new pilots a day isn't really true. :dunno:
 
One of my primary instructors was a crusty old high-time pilot (somewhere between 10-15,000 hours, IIRC, all in pistons). He was (and still is) an A&P/IA also. I recall him telling me he'd never had an engine failure resulting in an off-airport landing. He also was of the opinion, based on his A&P experience, that aircraft piston engines nowadays are so reliable that the risk of catastrophic, sudden failure is so unlikely as to not be worth worrying about -- as long as the engine is properly operated and maintained.

So I think the statistic cited by the OP is a little tough to swallow. Nevertheless, I continue to practice engine-out scenarios, and always try to be mindful of places I could set it down if I had to. After all, people win multi-million dollar lotteries on a somewhat regular basis...and what are the odds of any one individual doing that?
 
BrianR said:
One of my primary instructors was a crusty old high-time pilot (somewhere between 10-15,000 hours, IIRC, all in pistons). He was (and still is) an A&P/IA also. I recall him telling me he'd never had an engine failure resulting in an off-airport landing. He also was of the opinion, based on his A&P experience, that aircraft piston engines nowadays are so reliable that the risk of catastrophic, sudden failure is so unlikely as to not be worth worrying about -- as long as the engine is properly operated and maintained.

So I think the statistic cited by the OP is a little tough to swallow. Nevertheless, I continue to practice engine-out scenarios, and always try to be mindful of places I could set it down if I had to. After all, people win multi-million dollar lotteries on a somewhat regular basis...and what are the odds of any one individual doing that?
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That has always been the situation, that's why mechanics always preach ROP, because without it, they'd have to find a second job. Luckily though, most people are clueless when it comes to their equipment.
 
If you fly under 50hrs a month dont worry about it, just make sure you keep up with your required mx (at a good shop) and just fly.

Chances are non-proficient folks will fail as PIC LONG before those pistons fail you.

The ratio of mach 1 landings in 172s and squirrely old weekend warriors swerving their carbon cubs down a 10k runway, compared to piston engine failures, well the little bit of danger in aviation aint because of "those small airplanes".
 
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Prior to college graduation I knew two people who died in car wrecks and 4 who died in plane crashes. During the ensuing 50+ years I've known one car-wreck victim and three pilots from my hangar row alone who have been killed in air crashes.

In addition, I can think of another 16 pilots and pax without extensive effort, including Howard Pardue who recently crashed his Bearcat at KBKD. I don't know how these numbers compare to those from non-pilots who don't know people at the airport, but would be willing to bet that similar ratios would hold true for us airport bums.



Z06_Mir said:
Oh really? I worked line for 5 years in two different locations, both my parents were pilots, their friends were pilots. Now I'm a pilot, making my own pilot friends (which I have several of, BTW). I guess meeting 20+ new pilots a day isn't really true. :dunno:
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wabower said:
Prior to college graduation I knew two people who died in car wrecks and 4 who died in plane crashes. During the ensuing 50+ years I've known one car-wreck victim and three pilots from my hangar row alone who have been killed in air crashes.

In addition, I can think of another 16 pilots and pax without extensive effort, including Howard Pardue who recently crashed his Bearcat at KBKD. I don't know how these numbers compare to those from non-pilots who don't know people at the airport, but would be willing to bet that similar ratios would hold true for us airport bums.
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My perception is about the same as yours. I've known two people killed in car accidents and those both happened before I graduated college. I can't think of anyone else I've known who has died in a car accident since then although a friend was killed in a motorcycle accident a couple years ago, rear-ended by a drunk driver.

I don't keep a count of people I've known who were killed in airplanes but it far outnumbers three and almost all of them were not beginners.
 
Everskyward said:
My perception is about the same as yours. I've known two people killed in car accidents and those both happened before I graduated college. I can't think of anyone else I've known who has died in a car accident since then although a friend was killed in a motorcycle accident a couple years ago, rear-ended by a drunk driver.

I don't keep a count of people I've known who were killed in airplanes but it far outnumbers three and almost all of them were not beginners.
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There is usually a line about what an experienced pilot he was. Like Sparky Imeson, who I used to chat with at Johnson Creek.
 
kgruber said:
There is usually a line about what an experienced pilot he was. Like Sparky Imeson, who I used to chat with at Johnson Creek.
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Come to think of it, I have met and spoken with Sparky Imeson too, when he flew a Cheyenne based in the same large hangar bays as we were. Also come to think of it, just like Wayne, I guess I've known three people killed in separate accidents from those bays. The other two were experienced guys in warbirds. One was flying in loose formation with Sparky when it happened. That was many years ago.
 
Everskyward said:
Come to think of it, I have met and spoken with Sparky Imeson too, when he flew a Cheyenne based in the same large hangar bays as we were. Also come to think of it, just like Wayne, I guess I've known three people killed in separate accidents from those bays. The other two were experienced guys in warbirds. One was flying in loose formation with Sparky when it happened. That was many years ago.
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All you really need to do is go out to Kenmore Air Harbor. Out in the back shed they have piles of landing gears from airplanes that have just disappeared, or crashed.
 
Does it count if I know people who I expect will kill themselves but haven't yet?
 
kgruber said:
Only those who are on this forum!
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While I do have my suspicions regarding certain forum members, none of them are the experienced folks.

One experienced pilot I know not on the forum, though, I fully expect to be an NTSB report. Many will say "He was so experienced!" I will say "I saw that one coming..."
 
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