New valve technology on the horizon

Crashnburn

Pattern Altitude
Joined
Aug 8, 2018
Messages
1,651
Location
Sunnyvale CA
Display Name

Display name:
Crashnburn
Might eventually replace the poppet valves in our IC engines with barrel valves. These would be simpler, generate more power with the same displacement, allow higher revving engines, and probably not require as high an octane level.

As these are still in the developmental stage, they'd probably show up in EAB planes long before the FAA certifies them.

https://www.msn.com/en-us/autos/new...A17fKma?cvid=246a1e9aaeea47d382009b12464f67b6
 
It’ll all be EV ball bearings and fetzer valves by then.
I don't think so. Battery energy density is significantly less than petroleum-based fuels, and you don't get to trade battery weight for payload as you can with petroleum-based fuels.
Also, all the energy an EV uses has to come from somewhere, it doesn't just magically appear. And, you don't get as much energy out of a battery as you put into it.
Finally, there's currently only enough lithium battery storage in the world to power the world for a few seconds.
Not to mention lithium mining is extremely eco-unfriendly.

All that said, I'm not against EV's. I just don't think they come close to living up to their hype.

I forgot to mention that lithium batteries are essentially time-bombs. Last week a Tesla caught fire while it was out on the freeway. And I remember the new Boeings having issues and fires with lithium batteries.
 
In any machine I designed and built, sliding surfaces gave me the most trouble. That valve has a lot of sliding surface that has to seal tightly, has to turn freely, and has to stay sealed even with differences in coefficients of thermal expansion and uneven heating of the whole rotor. Moreover, the ports are smaller than those offered by poppet valves, so there goes the efficiency.

That's in the popular press, the same press that went all crazy over cold fusion, flying cars, and many other unworkable ideas. Journalists are among the most gullible people. And they make money hyping stuff like this. I can remember magazines like Popular Mechanics and Mechanix Illustrated in the '60s and '70s, with a cover story on some "new, revolutionary engine" every few months. Of the dozens I saw, only one succeeded: the Wankel rotary. And even that one didn't take over.
 
Not a new idea, large surfaces like that do not maintain their seal that well over time. Even Wankels struggle with this.
 
I don't think so. Battery energy density is significantly less than petroleum-based fuels, and you don't get to trade battery weight for payload as you can with petroleum-based fuels.
Also, all the energy an EV uses has to come from somewhere, it doesn't just magically appear. And, you don't get as much energy out of a battery as you put into it.
Finally, there's currently only enough lithium battery storage in the world to power the world for a few seconds.
Not to mention lithium mining is extremely eco-unfriendly.

All that said, I'm not against EV's. I just don't think they come close to living up to their hype.

I forgot to mention that lithium batteries are essentially time-bombs. Last week a Tesla caught fire while it was out on the freeway. And I remember the new Boeings having issues and fires with lithium batteries.


EVs are very close to being a great alternative to ICE for personal transport. In fact for many, it is a great alternative. The fire issue will get better, it's already pretty good. Don't forget pound for pound gasoline has much more energy than a lithium cell and will do much more damage in a runaway situation.

We are close, for ground based small vehicle transport anyway.
 
Don't forget pound for pound gasoline has much more energy than a lithium cell and will do much more damage in a runaway situation.
I'd like to know the rate of runaway fires in gasoline vehicles versus lithium battery vehicles. The rate, not raw numbers, but how many per thousand vehicles. And how many gasoline vehicles are recommended, by their manufacturers, to be parked well away from any buildings...
 
According to the article, the barrel valves run coot, they've solved the clearance problem, and you can separate the intake and exhaust valves.
 
I don't think so. Battery energy density is significantly less than petroleum-based fuels, and you don't get to trade battery weight for payload as you can with petroleum-based fuels.
Also, all the energy an EV uses has to come from somewhere, it doesn't just magically appear. And, you don't get as much energy out of a battery as you put into it.
Finally, there's currently only enough lithium battery storage in the world to power the world for a few seconds.
Not to mention lithium mining is extremely eco-unfriendly.

All that said, I'm not against EV's. I just don't think they come close to living up to their hype.

I forgot to mention that lithium batteries are essentially time-bombs. Last week a Tesla caught fire while it was out on the freeway. And I remember the new Boeings having issues and fires with lithium batteries.
The 787's? That was years ago. They fixed that. Lithium fires are rather rare. @PaulS posted a reference above. About 213,000 cars catch fire per year in the USA, while only 52 EVs caught fire. I think the numbers there are contradictory as I read the article. The newer solid state batteries that are starting to be put in EVs don't have the fire problem. Finally, they are evaluating sodium as a replacement for lithium although I don't expect that to happen for several years.
 
There are a plethora of ICE designs that offer certain advantages compared to the ancient relics that we’re still hanging on the front of new airplanes. It is unlikely that we will ever see any of them on a certificated airframe, for the following reasons: 1). They’re ICEs; 2). Development and certification costs are staggering; 3). The timeline from inception to certification is long; 4). Investment money (which is relatively scant for any GA-related endeavor anyway) sees electric propulsion as the future.

As for electric propulsion, the electric motor is far superior to an ICE engine in almost every respect. But it will take a quantum leap in battery technology to make electric airplanes a practical reality, and such technologies must develop energy storage systems that do not have the potential for catastrophic fires. And, as Crashnburn pointed-out, range/payload tradeoffs that are easily managed with liquid fuels will be much more challenging to accommodate with electric propulsion, which presents a significant challenge. But from my perspective, the biggest drawback to electric propulsion is that it doesn’t sound like a big ol’ radial (this from a guy who happily sits behind a 7-cylinder ICE developed during the Hoover administration, enjoying the soul-stirring song of the exhaust stacks while hoping that the melody doesn’t suddenly stop like an aeronautical version of musical chairs).
 
There are a plethora of ICE designs that offer certain advantages compared to the ancient relics that we’re still hanging on the front of new airplanes. It is unlikely that we will ever see any of them on a certificated airframe, for the following reasons: 1). They’re ICEs; 2). Development and certification costs are staggering; 3). The timeline from inception to certification is long; 4). Investment money (which is relatively scant for any GA-related endeavor anyway) sees electric propulsion as the future.

As for electric propulsion, the electric motor is far superior to an ICE engine in almost every respect. But it will take a quantum leap in battery technology to make electric airplanes a practical reality, and such technologies must develop energy storage systems that do not have the potential for catastrophic fires. And, as Crashnburn pointed-out, range/payload tradeoffs that are easily managed with liquid fuels will be much more challenging to accommodate with electric propulsion, which presents a significant challenge. But from my perspective, the biggest drawback to electric propulsion is that it doesn’t sound like a big ol’ radial (this from a guy who happily sits behind a 7-cylinder ICE developed during the Hoover administration, enjoying the soul-stirring song of the exhaust stacks while hoping that the melody doesn’t suddenly stop like an aeronautical version of musical chairs).
Yes to all of that. And yes, our current aircraft engines are technologically behind auto engines now.

BUT. If a person wants to fly anywhere, he/she has to either accept one of those engines, or pay someone for a conversion that will be less than ideal and reliable, and certainly not cheap, or do it themselves. My more recent experience tells me that there are very few people anymore with the wherewithal do develop and built anything. Most people can't even built a birdhouse from raw materials, never mind build an aircraft engine. Or an airplane.

These old engines have flown reliably for many decades, if they're cared for properly. They fail if they're not, or if the pilot has no clue about carb ice and leaning and similar stuff. Of if he forgets to switch tanks. Or if he never checks the oil. They are not, and never will be car engines, and you actually have to think and learn about some stuff.

I get a bit bugged when some folks start in condemning legacy engines as "dinosaurs." Well, then, stay on the ground, or build your own engine. There aren't many choices here. This engine-bashing has been going on since I joined EAA in 1972 and started flying in '73, and it was going on before that. Most homebuilders would bash those engines until they had to buy one for their project, or until they started flying lessons behind one of them. Most criticism arises out of ignorance and inexperience.
 
Just ran across this video. https://www.msn.com/en-us/news/us/o...A17cIEi?cvid=02e0b3f0c2ca4f35b78a2277324526f8
Apparently Li-Ion battery fires are increasing. Gasoline doesn't spontaneously combust.
https://bailyagency.com/blog/spontaneous-combustion-fire-safety/
Auto Oils and Gasoline
While not as likely to spontaneously catch fire, rags that soaked in engine oil or gasoline can self-combust. If you have a gasoline spill in your garage or workshop and use rags to clean it up, those rags left in a pile could spontaneously combust.
 
https://bailyagency.com/blog/spontaneous-combustion-fire-safety/
Auto Oils and Gasoline
While not as likely to spontaneously catch fire, rags that soaked in engine oil or gasoline can self-combust. If you have a gasoline spill in your garage or workshop and use rags to clean it up, those rags left in a pile could spontaneously combust.
That is due to oxidation or fermentation, which releases heat. Rags in a pile will accumulate that heat and could combust. Anytime we used rags to clean up flammables, they were either thrown out right away, or hung on something to dry quickly. About the worst thing was a rag wet with alodine. That's a real combustor.

But fuel in a car or airplane? Nope. No spontaneous combustion.

The pulp mills in BC had a problem with their chip piles. The weight of the chips compressed the lower layers, inhibiting air movement, and any moisture in the chips resulted in the oxidation and heating of the pile and it would burst into flame and be a real stubborn fire. Now they constantly turn the piles over using bulldozers.

https://en.wikipedia.org/wiki/Spontaneous_combustion
 
That is due to oxidation or fermentation, which releases heat. Rags in a pile will accumulate that heat and could combust. Anytime we used rags to clean up flammables, they were either thrown out right away, or hung on something to dry quickly. About the worst thing was a rag wet with alodine. That's a real combustor.

But fuel in a car or airplane? Nope. No spontaneous combustion.

The pulp mills in BC had a problem with their chip piles. The weight of the chips compressed the lower layers, inhibiting air movement, and any moisture in the chips resulted in the oxidation and heating of the pile and it would burst into flame and be a real stubborn fire. Now they constantly turn the piles over using bulldozers.

https://en.wikipedia.org/wiki/Spontaneous_combustion
My post was sufficient to disprove his claim that gasoline doesn't spontaneously combust.
 
So I try not to let media or people with an ax to grind influence my opinion on things. Here is another quick google result. Fires per 100,000 vehicles. Gasoline 1,529.9 versus 25.5 for EVs. Surprisingly Hybrids had the highest rate of fires at 3,474.5 per 100,000 vehicles. These numbers don't lie, of course the sample size is smaller on the EVs, but not insignificant.

How Much Should You Worry About EV Fires? (autoweek.com)
 
Might eventually replace the poppet valves in our IC engines with barrel valves. These would be simpler, generate more power with the same displacement, allow higher revving engines, and probably not require as high an octane level.

As these are still in the developmental stage, they'd probably show up in EAB planes long before the FAA certifies them.

https://www.msn.com/en-us/autos/new...A17fKma?cvid=246a1e9aaeea47d382009b12464f67b6
Higher-revving engines? You can buy a car with poppets that revs to 9K, motorcycles to 15K, even the Rotax 91X series cruises at essentially twice the LyCon RPM.
BTW, my brother and I came up with that scheme decades ago, only to find that it was already done. So this isn't new by any means.
A properly designed modern engine would make decent power and burn automobile pump gas. With ethanol. Hey, there's that Rotax again!
 
Meh. Wake me when it comes to market and folks are buying en masse.
 
So I try not to let media or people with an ax to grind influence my opinion on things. Here is another quick google result. Fires per 100,000 vehicles. Gasoline 1,529.9 versus 25.5 for EVs. Surprisingly Hybrids had the highest rate of fires at 3,474.5 per 100,000 vehicles. These numbers don't lie, of course the sample size is smaller on the EVs, but not insignificant.

How Much Should You Worry About EV Fires? (autoweek.com)
Many ICE fires are electrical and have nothing to do with the engine or fuel. GM ignition switches. Who had the shorting/burning headlight switch? Ford?
 
Many ICE fires are electrical and have nothing to do with the engine or fuel. GM ignition switches. Who had the shorting/burning headlight switch? Ford?

My take is regardless of the fire source, the rate of fire per 100,000 vehicles is about 60 times higher for ICE cars than EVs. Hard to argue with those numbers. Furthermore I would say that EVs are still in the dark ages as to their development and technology. Things should only get better.
 
More combustible material? More ignition sources?
Maybe the much more frequent charging while being driven. High current fast charging of Li batteries next to a tank full of gasoline while things are getting bounced around… hmm, is there anything left we could do to increase the risk factors? How about adding some explosives, or an ex girlfriend for a mechanic?
 
Many ICE fires are electrical and have nothing to do with the engine or fuel. GM ignition switches. Who had the shorting/burning headlight switch? Ford?
EV's also have electrical systems so there is more happening than the numbers show. EVs are newer compared more ICE cars that are older with worn out wiring? The electrical problem ignites oil? Crashes rupture fuel tanks/lines and ignite fires?
 
Last edited:
So I try not to let media or people with an ax to grind influence my opinion on things. Here is another quick google result. Fires per 100,000 vehicles. Gasoline 1,529.9 versus 25.5 for EVs. Surprisingly Hybrids had the highest rate of fires at 3,474.5 per 100,000 vehicles. These numbers don't lie, of course the sample size is smaller on the EVs, but not insignificant.

How Much Should You Worry About EV Fires? (autoweek.com)

1500 fires per 100K vehicles? That's 1.5% which seems awfully high. Over 1 in 100 gas vehicles will catch fire? Seems unlikely. But their methodology isn't clear; they're reporting fires per 100K "sales"... sales of what?

To be meaningful, any study would have to account for vehicle age, miles driven, etc., etc.

Not saying EVs aren't safer, just that I've seen no convincing data either way.
 
1500 fires per 100K vehicles? That's 1.5% which seems awfully high. Over 1 in 100 gas vehicles will catch fire? Seems unlikely. But their methodology isn't clear; they're reporting fires per 100K "sales"... sales of what?

To be meaningful, any study would have to account for vehicle age, miles driven, etc., etc.

Not saying EVs aren't safer, just that I've seen no convincing data either way.

It's supposedly from an insurance company study, so I would suspect it's pretty close to true. That's the problem with going with gut feel or perceptions or media reports. They are usually woefully incorrect.
 
These old engines have flown reliably for many decades, if they're cared for properly. They fail if they're not, or if the pilot has no clue about carb ice and leaning and similar stuff. Of if he forgets to switch tanks. Or if he never checks the oil. They are not, and never will be car engines, and you actually have to think and learn about some stuff.

I get a bit bugged when some folks start in condemning legacy engines as "dinosaurs." Well, then, stay on the ground, or build your own engine. There aren't many choices here. This engine-bashing has been going on since I joined EAA in 1972 and started flying in '73, and it was going on before that. Most homebuilders would bash those engines until they had to buy one for their project, or until they started flying lessons behind one of them. Most criticism arises out of ignorance and inexperience.

Problem is, many engine failures occur through no fault of the pilot or AMT. Failed valves, thrown rods, snapped crankshafts and camshafts, cylinder barrel/head separations... those are failures that just shouldn't occur. Some problems might have been detected prior to failure, but many were not apparent until the music stopped.

Given that the consequences are potentially lethal, our goal should be ZERO inflight failures and any engine failure should be unacceptable. We may acknowledge the fact that a zero failure rate is unachievable, but that should be the goal nonetheless and the engines available today fall far, far short of that. Even non-injury engine failure accidents are expensive to the GA community, and our escalating insurance rates reflect the magnitude of the problem.

Whether or not we like the characterization, the Continental and Lycoming engines that dominate GA ARE dinosaurs. The engine on a brand new million-dollar Cirrus is a 1950s artifact, kept on life-support by the economic impracticality of producing a modern replacement. Meanwhile, the technical advancement of automotive engines surpassed that of piston aircraft engines a long, long time ago. As far as I know, there exists no reliable data to directly compare the reliability of GA engines to auto engines, but it’s clear that the reliability of auto engines has steadily and dramatically increased since the 1950s whereas the reliability of piston aircraft engines has not. I’ve not experienced a catastrophic engine failure in a car, ever. I’ve had two in airplanes, one of which left me in a field, a long stroll from civilization—it does tend to change one’s perspective. I know many other pilots who have had aircraft engines fail at inconvenient times. Even new-and-improved replacement components, such as cylinders, have failed prematurely, notoriously, and expensively, for reasons that are unpardonable today. Whenever this matter is raised it is usually accompanied by a chorus of apologizers and defenders, whose rationale seems to be that because it’s an airplane engine, we must excuse, forgive, overlook, and rationalize its shortcomings. When engines malfunction, it’s our fault, right? We were ignorant; we were careless; we were negligent; we had a bad childhood... And yes, sometimes it is our fault, but too often it is not.

The technology and production capability exists to produce powerplant systems that are extremely reliable and efficient, and that manage themselves without requiring pilots to act simultaneously as a problem-solving PIC and as a knob-twiddling gage-gazing flight engineer. The development and production of such technically advanced powerplants would greatly increase safety and efficiency in GA operations, but so long as certification costs are insanely prohibitive and investment is scant, and so long as we are willing to buy new airplanes with 1950s engines, we will continue to ride our dinosaurs until electric propulsion becomes practical or GA goes the way of the steam locomotive.
 
Even non-injury engine failure accidents are expensive to the GA community, and our escalating insurance rates reflect the magnitude of the problem.
Where's your data to back that up? A quick glance at the latest Nall report says non-commercial fixed wing aircraft had 892 total accidents in 2020 (latest year with final numbers), of which only 77 were powerplant related. With those numbers, it's not obvious to me that "dinosaur engines" are a significant contributor to "escalating insurance rates".

I'd say 77 total powerplant-related accidents is a better reflection of the magnitude of the problem, and that the magnitude is not so big.

The technology and production capability exists to produce powerplant systems that are extremely reliable and efficient, and that manage themselves without requiring pilots to act simultaneously as a problem-solving PIC and as a knob-twiddling gage-gazing flight engineer. The development and production of such technically advanced powerplants would greatly increase safety and efficiency in GA operations, but so long as certification costs are insanely prohibitive and investment is scant, and so long as we are willing to buy new airplanes with 1950s engines, we will continue to ride our dinosaurs until electric propulsion becomes practical or GA goes the way of the steam locomotive.
The technology is there, certainly. The problem is that the market is not. There are relatively few who can afford to buy new airplanes with 1950s engines. There would be far fewer who could afford to buy new airplanes with 2020s engines. And for those of us who can only afford to buy and fly 40+ year old planes because of the relative simplicity and ease of maintenance of the 1950s technology propelling them, this argument is moot.
 
Last edited:
Oh geez, not the auto tech vs dinosaurs argument again. :mad2:
 
  • Like
Reactions: BPM
Oh geez, not the auto tech vs dinosaurs argument again. :mad2:
Again. And again. So I will rebut.

Problem is, many engine failures occur through no fault of the pilot or AMT. Failed valves, thrown rods, snapped crankshafts and camshafts, cylinder barrel/head separations... those are failures that just shouldn't occur. Some problems might have been detected prior to failure, but many were not apparent until the music stopped.

Catastrophic failures are really rare. You know what usually fails? The magnetos, because they weren't faithfully inspected and maintained every 500 hours like they're supposed to be. So they quit, sometimes in a really bad way such as sending sparks to the wrong cylinders so that the engine nearly dies. The plastic magneto gears were worn and degraded because the mag had 1400 hours on it since it was last apart, and the age and heat did the degrading as well. I have found rusted bearings in a magneto. Just waiting to fail in flight.

Throw rods are due to oil starvation. That's not the engine maker's fault. The pilot didn't check the oil every often at all. Or the owner didn't get those 40-year-old oil cooler hoses replaced every five years like he should, and one failed and dumped all the oil overboard.

I, too, had two failures. The carb fell off the first airplane because the hardware had no locking on it at all. No lockwire, cotter pins, lock washers, nothing. That's not the engine designer's fault. That's the mechanic's. The second was a busted crank, from someone's propstrike that they likely didn't report. The crank cracked, and then broke when I was flying it. The crack was easily seen once we took it apart. More lack of proper maintenance.

Given that the consequences are potentially lethal, our goal should be ZERO inflight failures and any engine failure should be unacceptable. We may acknowledge the fact that a zero failure rate is unachievable, but that should be the goal nonetheless and the engines available today fall far, far short of that. Even non-injury engine failure accidents are expensive to the GA community, and our escalating insurance rates reflect the magnitude of the problem.

Our governments want 100% safety, too. They have 99.999% now, but that last .001% will make aviation too expensive for all of us. It would require much more QA, at every step of maintenance and manufacture, and pilots would need 200 hours for a PPL and 500 for a Commercial and 1000 for IFR....get the idea?

Whether or not we like the characterization, the Continental and Lycoming engines that dominate GA ARE dinosaurs. The engine on a brand new million-dollar Cirrus is a 1950s artifact, kept on life-support by the economic impracticality of producing a modern replacement.

That idea comes from ignorance, They LOOK the same. They are NOT the same. The metallurgy, and many other things, have changed dramatically. I have posted, before, many areas that have been improved in modern engines. As a mechanic I dealt with those improved things all the time. They made my 1946 A-65 look really ancient.

Meanwhile, the technical advancement of automotive engines surpassed that of piston aircraft engines a long, long time ago. As far as I know, there exists no reliable data to directly compare the reliability of GA engines to auto engines, but it’s clear that the reliability of auto engines has steadily and dramatically increased since the 1950s whereas the reliability of piston aircraft engines has not.

Nope. The reliability of a Lycoming is much better than that of an auto engine, if it's maintained. Most aren't. Not nearly well enough. And most failures, around 90%, are electrical in nature: magnetos versus all the computers and sensors and connections in the modern auto. I have had plenty of electrical troubles in my motor vehicles, and almost none with my magnetos. 1946 magnetos. Look after them and they keep going.

I was the director of maintenance with a flight school. We ran Lycomings all the way to TBO with no issues. Not a single engine failure in maybe 35,000 hours while I was there. They still had compressions in the high 70s, no metal in the filters, and could have been stuck in homebuilts and run another 2000 hours. And these engines were run hard in the flight school, by ham-fisted students.

Aircraft engines are working at 65-100% power almost all the time they're in the air. Auto engines are cruising at 25% power, and almost never get pushed to 100% for more than a few seconds. Like I've said so many times, aircraft engines are not car engines. That's the mistake most people make. The aircraft engines we have now are doing admirably well considering the performance expected of them.

I’ve not experienced a catastrophic engine failure in a car, ever. I’ve had two in airplanes, one of which left me in a field, a long stroll from civilization—it does tend to change one’s perspective.

See above. Me, too. Many failures such as head separations or cracked pistons are the pilot's fault. Detonation from poor mixture management, or from overboosting, or from just opening that throttle too fast.

and so long as we are willing to buy new airplanes with 1950s engines, we will continue to ride our dinosaurs

Not until you're willing to pay $150K+ for a nice new modern aircraft engine, yes. 12 years ago I did a bunch of work on an SMA diesel in a 182. At that time, SMA had 50 of those engines flying worldwide, and they had spent one billion dollars so far, at that time, on its development and certification. The conversion, in 2009 dollars, was around $100K, to put it in a 182. So of course there are no new piston engines. Nobody will buy them when they're going to cost hundreds of thousands. The safety culture of our society has done this. We sue at the drop of a hat, so the manufacturers have to design idiot-proof stuff, an impossible task, and the governments want flawless perfection, too, and that just drives certification costs out of sight. Unless we start admitting that we cannot have perfection, and are willing to tolerate some risk, we won't see affordable new engines, and even the electric stuff will be expensive after certification. We'll still expect zero-risk performance.
 
Last edited:
Jim_R and Dan Thomas,

Thank you both for taking the time to illustrate some of my points.
 
Where's your data to back that up? A quick glance at the latest Nall report says non-commercial fixed wing aircraft had 892 total accidents in 2020 (latest year with final numbers), of which only 77 were powerplant related. With those numbers, it's not obvious to me that "dinosaur engines" are a significant contributor to "escalating insurance rates".

I'd say 77 total powerplant-related accidents is a better reflection of the magnitude of the problem, and that the magnitude is not so big.

And many of those 77 will not be the manufacturer's fault. Owners too cheap to replace ancient oil cooler hoses so that they rupture and blow all the oil overboard so the engine seizes. A failure to get 500 hour (Slick) or 400-hour (Bendix) mag inspections done, and mag failure, if it's related to failed distributor gearing or a corroded impulse spring, can be pretty serious. If the mag's bearings fail due to age and corrosion, bearing bits and maybe even busted mag drive parts fall into the machinery in the accessory case and trash everything, and the fire goes out. Running low on oil. Bashing the throttle open on takeoff, or overboosting with a manual wastegate, can cause destructive detonation. Tolerating significant oil leaks to the point where a seal fails altogether. And how about carb ice, ice that disappears long before the investigators get there so that they cannot conclusively blame it for the failure, but fail it did, and nothing else found wrong with it.

And sometimes mechanics mess up and cause a failure, too.

Dinosaurs? No. That implies unreliability, and that's a false accusation.
 
Jim_R asked for data to back-up my argument, and then went on to provide it for me. The fact that 77 powerplant-related accidents occurred in a single year is more than sufficient supporting data. 77 accidents (10 with fatalities) is WAY too many. But that’s just the data for a single year, a year in which the pandemic may have skewed the numbers, so let’s dig a little deeper for additional perspective. An NTSB statistical digest encompassing the ten-year period from 2012 to 2021 reveals that powerplant failures were the “defining event” in a total of 2050 accidents during that period, of which 214 resulted in one or more fatalities. That averages 205/year total; 21.4/year fatal. And again, that is WAY too many. It should be noted that, of all accident causes cited by NTSB, powerplant failures ranked second, right below inflight loss-of-control. In addition to being a sobering topic of contemplation, in a single-engine aircraft, at night, over unfriendly terrain, the data does back-up my argument.

Dan Thomas, you bristle at the characterization of GA piston engines as dinosaurs. In rebuttal you argue that (relatively) recent production incorporates numerous improvements compared to a 1930’s era A-65. True, but such a comparison is not persuasive: a lawnmower engine is more technically-advanced than a 1946 A-65. Current-production engines don’t just look the same--they are, essentially, the same, and they lag far behind the state of ICE technological advancement that has been available for decades.

You discussed magnetos and the maintenance thereof, and in doing so you once again failed to persuade me to embrace your point-of-view. Magnetos?! Magnetos are a defining characteristic of technical obsolescence. While I am in complete agreement with you regarding the necessity to address their special maintenance requirements, the mere existence of mags on an aircraft engine (per the TC) underscores the dinosaur characterization, and adds an exclamation mark.

As I predicted, you blamed pilots for causing engine failures through carelessness and incompetence. With regard to one of the examples you provided, the fact that an engine can be damaged by opening the throttle too quickly is, by modern standards, absurd. Current-state engine management technology would simplify engine operation and prevent overboost, overspeed, detonation, etc. while optimizing power and efficiency, resulting in a significant net gain in statistical reliability (there are other potential benefits that fall outside the scope of this discussion). Once again, the argument you offered in rebuttal serves only to support points made in my previous posts.

Dan Thomas, I’ve read many of your posts and have been impressed by your range and depth of knowledge, your experience, and by the care you take in crafting well-reasoned and well-written commentary. We seem to be making two very different arguments regarding engine reliability, one based on technical obsolescence and the other based on shoddy maintenance. I am in complete agreement with the points you make about the role poor maintenance and operating practices play in engine (un)reliability, but that doesn’t change the fact that these engines are technically obsolete, and have been for decades. A truly modern engine design should greatly reduce and simplify maintenance requirements and simplify operation, resulting in greater reliability over the entire design lifespan of the engine. We do appear to agree that the costs of development, certification, and ongoing support far exceed the potential ROI (as I had previously stated). So once again, thank you for illuminating the points that I made previously. GA engines are dinosaurs.

As a parting thought, maybe it’s just me, but I never presume that other forum members are ignorant dolts who must be set-straight, just because their perspectives differ from mine.
That idea comes from ignorance

Over and out...
 
the data does back-up my argument.
Unfortunately with any failure data it has to be put into its proper context. Given this “dinosaur” engine discussion has been going on for as long as I’ve been in aviation, there have been quite a number of detailed studies performed to understand these failure mechanisms. So to simply throw out numbers without context doesn’t make or break the discussion.

For example, true design based reciprocating engine failures are around 2-3% of all noted failure numbers. So in the examples above of 77 and 205 engine failures that should be corrected to 2 and 5 respectively. The remaining engine failure percentages all have an operational component involved vs a design fault.

In one overseas study, I recall they drilled down reciprocating failure mechanism to 3 modes: component melting, bearing behavior, and fatigue crack initiation which is a far cry from the standard fuel exhaustion, mechanical failure, etc. failure modes.

Another contextual adjustment that will change the above initial failure data would be to define the failures by operation type. You’ll find there are certain specific operations using reciprocating engines that have engine failure rates closer to turbine engines with the vast majority of the engines meeting TBO. Not a bad feat for a “dinosaur.”

And even turbine engines fail every year for the same basic reasons. But those would also be considered a “dinosaur” engine as they have remained generally unchanged from a design/function point of view. But turbines do provide a much lower failure rate than reciprocating engines for obvious reasons.

So I guess the questions to ask you are:

Which specific model(s) from the “plethora of ICE designs” you mentioned above would provide a better true failure rate than the current “dinosaur” variety of engines used today? And,

What other “current-state engine management technology” do you think would lower the failure rates on these “dinosaur” engines?
 
Last edited:
Jim_R asked for data to back-up my argument, and then went on to provide it for me. The fact that 77 powerplant-related accidents occurred in a single year is more than sufficient supporting data. 77 accidents (10 with fatalities) is WAY too many.

From https://wikiwings.com/how-many-general-aviation-aircraft-are-in-the-united-states/ I see this:

Over the next several weeks, we’ll blog a few factoids from the PricewaterhouseCoopers General Aviation report that was released in early 2020. Let’s start with, how many GA aircraft are there in the US? Answer: In 2018, the total GA fleet size was 211,743 aircraft. More than 173,000 had piston engine propulsion which represented 82% of the GA fleet.

So 77 engine-failure accidents out of 173,000 aircraft is 0.045%. That is presuming that all of those 77 were piston-engined aircraft, and it also does not note the number of engines, since twins would increase the engine numbers significantly.

The corollary to a 0.045% failure rate is that 99.955% of engines did not fail that year. And that's a bad number?? I wonder what the automobile engine failure rate is?

Granted, not all engines fly all the time, but even if only half of them fly regularly, that percentage of failures still isn't even a tenth of a percent. And I'd bet that the ones that don't fly regularly are more susceptible to failure. People who don't fly their airplanes tend to not spend money on them.

An NTSB statistical digest encompassing the ten-year period from 2012 to 2021 reveals that powerplant failures were the “defining event” in a total of 2050 accidents during that period, of which 214 resulted in one or more fatalities. That averages 205/year total; 21.4/year fatal. And again, that is WAY too many. It should be noted that, of all accident causes cited by NTSB, powerplant failures ranked second, right below inflight loss-of-control.

Please show the reference to that. Give us the slide to make it easier to see. Loss of control is far too common, with a lot of takeoff and landing accidents.

Dan Thomas, you bristle at the characterization of GA piston engines as dinosaurs. In rebuttal you argue that (relatively) recent production incorporates numerous improvements compared to a 1930’s era A-65. True, but such a comparison is not persuasive: a lawnmower engine is more technically-advanced than a 1946 A-65. Current-production engines don’t just look the same--they are, essentially, the same, and they lag far behind the state of ICE technological advancement that has been available for decades.

Lycoming switched to high-chromium content bronze valve guides in 1999. That was an era in which a lot of cars still had cast iron heads, and the valve guide was the iron itself. Lycoming now has roller lifters. They have sodium-filled exhaust valves. The valve alloy itself is nowhere near the same as it was in 1946, both for Lycoming and Continental. Chromium rings are sometimes used to reduce wear rates. Some cylinders are chromed and use the cast rings. None of this was done in 1946. Many engines are fuel injected, and were that way long before cars became commonly injected. There have been improvements in seals and sealants, heat-treatments, lubricants, metallurgy (Lycoming heads stopped cracking long ago), and so on.

What, then, is your maintenance experience that you can state definitively that engines have not improved in 8 decades??

You discussed magnetos and the maintenance thereof, and in doing so you once again failed to persuade me to embrace your point-of-view. Magnetos?! Magnetos are a defining characteristic of technical obsolescence. While I am in complete agreement with you regarding the necessity to address their special maintenance requirements, the mere existence of mags on an aircraft engine (per the TC) underscores the dinosaur characterization, and adds an exclamation mark.

See the complaints about Surefly, the people that make electronic ignition for aircraft:
https://www.pilotsofamerica.com/com...-tech-support-awful-engine-wont-start.137035/


As I predicted, you blamed pilots for causing engine failures through carelessness and incompetence. With regard to one of the examples you provided, the fact that an engine can be damaged by opening the throttle too quickly is, by modern standards, absurd. Current-state engine management technology would simplify engine operation and prevent overboost, overspeed, detonation, etc. while optimizing power and efficiency, resulting in a significant net gain in statistical reliability (there are other potential benefits that fall outside the scope of this discussion).

Well, if a pilot cannot be taught to respect the engine, he's hopeless and will eventually learn the hard way. What do you think of the car owner who is always accelerating as hard as he can away from the traffic light? Ever seen the smoke behind that car or pickup? He is abusing that vehicle, and deserves to pay for it. There is similarly no justification for a pilot to bash the throttle around. You're asking for more idiot-proofing, and where do we stop with that? Do we need the airplane to have AI so that it refuses to take off when the visibility is too low or the wind is too strong? Do we need antiskid brakes so the pilot doesn't blow the tires out? Maybe we need an airplane that just takes over, disconnects the pilot's controls, and turns around and goes home when the pilot is obviously incompetent. Be careful what you ask for.

This is Lycoming's iE2. It's been available for about 12 years already. Never seen one. Like ANY new aircraft engine design, it's expensive. You have the money? You can buy it. Don't complain that nobody has made a modern engine.

upload_2023-2-19_19-21-56.png

https://www.lycoming.com/engines/ie2

And then there are the SMA and Austro diesels. Full FADEC, electronic everything. Certified. Also very expensive. They weren't developed for the military, so we, the GA folks, have to pay for all that R&D. During and shortly after WW2 the military was buying a lot of piston-engine lightplanes, for training and reconnaissance and logistics, and the engine makers developed engines for those. We got the benefit of that.

Diamond's DA-42 with Austro diesels:

upload_2023-2-19_19-27-37.jpeg

Cessna 182 with SMA diesel:

upload_2023-2-19_19-28-32.jpeg

Continental bought the technology from SMA and Cessna was going to produce the diesel 182, but the price point killed it.
 

Attachments

  • upload_2023-2-19_19-1-5.png
    upload_2023-2-19_19-1-5.png
    37.4 KB · Views: 6
Last edited:
Back
Top