New valve technology on the horizon

I’ve been following aviation engine development since the mid-‘90s when I got interested in E-AB aircraft. In that time there’s been a lot proposals and some very interesting ideas, at least from an engineering perspective. The problem is they are going to remain just ideas. There’s no panaceas. I wish there were, but there is no reason, economic otherwise to adopt anything different in the gasoline powered segment than a standard Lycoming or Continental to operate in the environment they are designed for. There’s a reason why auto engine conversion adopters remain a fringe community in the E-AB world. Could you clean sheet something better— possibly but with a new Lycoming IO-540 pushing north of $55K, you couldn’t sell something new any cheaper and there’s not enough market to make it profitable for the manufacturer, even assuming us Dinosaur owners could somehow be enticed to switch. IOW, unless it’s a bolt-on improvement, new aircraft gas piston engine development is a dead well, I don’t care how great the idea is. That’s the cold reality of it. Best bet would be to focus on Diesel or Electric development.
 
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Best bet would be to focus on Diesel or Electric development.
With all the fuss over fossil fuels, I don't think anyone is going to sink a lot of money into more aircraft internal combustion engines. And with the very limited and very slowly progressing battery technology, we aren't going to see any serious and practical electric contenders anytime soon, never mind affordable contenders. We are stuck with what we have, and so pilots, if they want to fly, need to learn engine management and need to take care of their airplanes.

I'm old enough to have had to work a manual choke in a car. If you didn't get it right, you could flood it or run the battery dead, and be stuck for a long time. So we learned to do it and learned to figure out when it was flooded or if it was just too lean. And the old guys when I was a kid had had to learn to set the throttle and spark advance just so before they hand-cranked the engine. If they go that wrong, there was often a busted arm to teach one to learn it right. We had to deal with carb ice in old cars, too, before they got automatic induction air heating. And we had to learn to drive on the ice and in the mud, with no ABS or stability augmentation or locking differentials. But we learned it and it wasn't that hard.

Now we've been dumbed down by all the automation and don't want to learn how to operate older technology. The sad part there is that the human mind is capable of terrific learning, huge capacity that most of us barely scratch. Learn it, and all becomes easy. Don't learn it, and stay home and fly the computer sim instead, I guess.
 
The only reason I see Diesel as an alternative is turbines aren’t going away anytime soon. So JET-A, which is the most widely available fuel globally, is going to be available. Unfortunately diesel engine development is littered with failures so I’m not holding my breath.
 
at least the "failures" are cost and regulatory related not so much technology related

Diamond has proven this can be done. Don't forget that there are plenty of diesel planes flying around Europe

No magneto, natural low end torque, generally more abuse tolerant.. there are many reasons why these make sense in an aircraft (weight and cooling excluded)
 
The only reason I see Diesel as an alternative is turbines aren’t going away anytime soon.
I think small and micro turbines or some sort of hybrid will become the interim alternative before diesel moves more mainstream. Unless that is they develop a light weight block solution for diesels. The turbines can also use SAF which keeps the tree huggers happy. They're just starting to fly full scale conventional turbine/electric test aircraft with plans to scale back the turbine size as the electric size grows. But as mentioned batt tech will keep that idea small for now. However, the micro-turbines are making some inroads.
 
at least the "failures" are cost and regulatory related not so much technology related

Diamond has proven this can be done. Don't forget that there are plenty of diesel planes flying around Europe

No magneto, natural low end torque, generally more abuse tolerant.. there are many reasons why these make sense in an aircraft (weight and cooling excluded)
I've flown the Diamond DA-40NG (for my IR) and the Diamond DA-42NG (for my multi). They are very nice airplanes! But after talking at length with the flight school owner and some of their pilots, I don't want to own one. The DA-42 I got my multi in was in the shop for its 3rd head gasket in 600 hours. The school owner's comment to me: "I hate airplanes. I love flying but I hate airplanes" Now to be fair he's also got DA-40XLTs and C-172s in his line up. But the more I heard about actual and required maintenance on the diesels, while I'd love to fly them and think they are very cool tech, they are pricey to maintain. Not a panacea for piston airplanes either.
 
How many piston gasoline burning continuous duty rated engines are out there than run at 150-250+ hp? No automotive engine is designed to run under such a duty cycle. The current ‘dinosaur’ av engines do this at a relatively light weight.
 
But the more I heard about actual and required maintenance on the diesels, while I'd love to fly them and think they are very cool tech, they are pricey to maintain. Not a panacea for piston airplanes either.
I think aircraft diesels are going through the same painful process gasoline engines did in WWI and into the late 1920s. Short lives, lots of failures of many sorts. The Curtiss OX-5 was fantastically unreliable by modern standards. They were used in the Standard JN-4 "Jenny" and after the war they were plentiful and cheap as surplus, and many owners kept a few on hand.

I did some work on an SMA diesel about 12 years ago. It had teething problems and we had to replace a bunch of stuff. Only had maybe 200 hours on it, in a 182. Diesels have high compression; this one was only 15:1, and was turbocharged, and only four cylinders for 230 HP, so vibration was a problem. It cracked brackets leaking head gaskets and caused chafing of some stuff. The leaking gaskets let oil out; the head is partially oil-cooled. Huge oil cooler in the installation. The FADEC would not allow any throttle control until it was warmed up, and during warmup, at low RPM, it shook pretty bad. It had a composite MT prop, and I found a cracked blade and I think that vibration did that. The crankshaft accelerates and decelerates a lot with high compression and only four cylinders. That prop is the flywheel and has to absorb all that. The composite prop reduced the weight up front to allow for the heavier engine.
 
I think aircraft diesels are going through the same painful process gasoline engines did in WWI and into the late 1920s. Short lives, lots of failures of many sorts. The Curtiss OX-5 was fantastically unreliable by modern standards. They were used in the Standard JN-4 "Jenny" and after the war they were plentiful and cheap as surplus, and many owners kept a few on hand.

I did some work on an SMA diesel about 12 years ago. It had teething problems and we had to replace a bunch of stuff. Only had maybe 200 hours on it, in a 182. Diesels have high compression; this one was only 15:1, and was turbocharged, and only four cylinders for 230 HP, so vibration was a problem. It cracked brackets leaking head gaskets and caused chafing of some stuff. The leaking gaskets let oil out; the head is partially oil-cooled. Huge oil cooler in the installation. The FADEC would not allow any throttle control until it was warmed up, and during warmup, at low RPM, it shook pretty bad. It had a composite MT prop, and I found a cracked blade and I think that vibration did that. The crankshaft accelerates and decelerates a lot with high compression and only four cylinders. That prop is the flywheel and has to absorb all that. The composite prop reduced the weight up front to allow for the heavier engine.
I suspect you are correct. But I wonder if they'll get to survive the development process required? I do know that required (by Diamond) gearbox maintenance is one of the pricey bits even if they don't break. And the head gasket issue I mentioned Diamond still had no clue as to what was going on. Twin engine plane, the same engine blew the head gaskets every 200 hours. The other engine was just fine. (I'd guess from my car engine experience that something was warped or not flat (head or block) but supposedly they checked within tolerance.)

Flying those engines was really, really nice! 5gph per engine of Jet-A. DA-40 is a 140kt airplane. Single lever FADEC. Auto start. Just a really simple experience and a very efficient airplane. (With the turbos even better up high!)
 
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.
I suppose "too many" is in the eye of the beholder. Regardless, let's just say that yes, 77 (or 200 or whatever) powerplant incidents per year is too many.

Exactly how do you envision "modern engines" will solve that problem?

Let's just say that we can snap our fingers and instantly generate a perfect engine today. Let's even say that we can snap our fingers and make the development cost = zero. We're just going to replace the engines in current-production light piston singles (and twins?) with this perfect new engine without changing the base price of the aircraft. And lets outlaw the sale of legacy engines, for good measure.

How long would it take before these new planes become a significant enough fraction of the flying fleet of light aircraft before it would have any measurable effect on annual powerplant related failures?

Of course, holding the aircraft price constant with the new engine is ridiculous--it would take 10s or 100s of millions of dollars to accomplish this new engine development, and those costs are by necessity going to drive up the price of the aircraft. Now, factor in the increased sales prices and ask the same question?

Like it or not, our dinosaur engines are going to be around for a long time (if there is fuel available to run them on). Especially since the business case for new engine development just doesn't work.
 
I've flown the Diamond DA-40NG (for my IR) and the Diamond DA-42NG (for my multi). They are very nice airplanes! But after talking at length with the flight school owner and some of their pilots, I don't want to own one. The DA-42 I got my multi in was in the shop for its 3rd head gasket in 600 hours. The school owner's comment to me: "I hate airplanes. I love flying but I hate airplanes" Now to be fair he's also got DA-40XLTs and C-172s in his line up. But the more I heard about actual and required maintenance on the diesels, while I'd love to fly them and think they are very cool tech, they are pricey to maintain. Not a panacea for piston airplanes either.
I've heard similar, but it's also relatively new tech that's going to have slow teething issues. And the volume is extremely low compared to the legacy fleet so those teething issues will be prolonged. This past week I had three flights canceled because of various anomalies with starters batteries etc. Planes are finicky beasts
 
How many piston gasoline burning continuous duty rated engines are out there than run at 150-250+ hp? No automotive engine is designed to run under such a duty cycle. The current ‘dinosaur’ av engines do this at a relatively light weight.
Your typical automotive engine is also somewhere between 1.5L and 2.5L, compared to somewhere between 6L and 9.5L for a typical plane engine.. plane engines are hardly abused. Sitting at one power setting with a relatively low RPM for hundreds of hours is far less abusive than constantly idling and revving over and over again..

Not necessarily advocating for automotive tech (loads of issues with cooling, gear reduction for propellers, and weight, etc) but it's not like our plane engines live harder lives..
 
Your typical automotive engine is also somewhere between 1.5L and 2.5L, compared to somewhere between 6L and 9.5L for a typical plane engine.. plane engines are hardly abused. Sitting at one power setting with a relatively low RPM for hundreds of hours is far less abusive than constantly idling and revving over and over again..

Not necessarily advocating for automotive tech (loads of issues with cooling, gear reduction for propellers, and weight, etc) but it's not like our plane engines live harder lives..
I respectfully disagree. The majority of automotive engines rarely, if ever, are pushed to their maximum hp. Mostly they are operated at a power level much less than the percentage of their max hp as compared to an aircraft engine. Think of running a car uphill at 60-75% of full throttle for several hours on end and doing this near every time it is run. I submit that the aircraft engine is performing more work when it is run compared to automotive engines. A more apropos comparison would be a marine engine running a large and heavy planing hull. In that realm large relatively slow turning diesel engines are the norm and a high performance high output per cylinder engine has a TBO close to an aircraft engine when run at 75%. Our engines are a fraction of the weight/hp of an equivalent continuous duty marine engine and are aircooled to boot. I think that they are very reliable considering.
 
I respectfully disagree. The majority of automotive engines rarely, if ever, are pushed to their maximum hp. Mostly they are operated at a power level much less than the percentage of their max hp as compared to an aircraft engine. Think of running a car uphill at 60-75% of full throttle for several hours on end and doing this near every time it is run. I submit that the aircraft engine is performing more work when it is run compared to automotive engines. A more apropos comparison would be a marine engine running a large and heavy planing hull. In that realm large relatively slow turning diesel engines are the norm and a high performance high output per cylinder engine has a TBO close to an aircraft engine when run at 75%. Our engines are a fraction of the weight/hp of an equivalent continuous duty marine engine and are aircooled to boot. I think that they are very reliable considering.

You have to also consider displacement. Most cars will use about 25% of their "rated" hp in cruise. Most planes 65%

Take a typical 180 hp 2.2 liter car engine and compare to a 180 hp 6 liter Lycoming.. both in cruise. Car at 25% and lyco 65%

(180 X .65)/6= 19.5 hp per liter lyco

(180 X .25)/2.2= 20.5 hp per liter car

They're nearly same. Sure, weight is definitely a factor in how beefy can you build that engine, most marine environments are less weight sensitive so you can afford to overbuild them, but our engines aren't exactly on the bleeding edge of technology. Most are 1960s era designs. Simple and generally reliable enough. There's just not enough volume out there to justify anything "new" from a cost or regulatory perspective
 
Auto engines are tested at the factories during their development. They're often run at wide open throttle and maximum load to see how long they will last, and many of them go hundreds of hours. Structurally they are strong enough. It's the cooling issues that get a lot of homebuilt conversions, and the redrive (PSRU) is an even bigger failure point.

There have been some workable versions. There have been some dangerous versions marketed by people who did not test them. Many of the workable versions are not marketed because the builder doesn't want the liability. He just wanted to tinker and experiment.

Aircraft engines are almost all direct-drive, to escape the hassles of the PSRU. Direct-drive engines must produce their power at lower RPM, so they have large cylinders to get the area to convert the pressures to usable torque. They have large, heavy valves to take the heat and sink it into the valve seat and valve guide. If you look at the valves in a Subaru 2.2L, 130 HP four per cylinder, then at the valves in an O-235, 125 HP, two per cylinder, the difference is stark. I had the Soob apart to repair a burnt valve in the engine I put in a Glastar, and those valves looked like they came out of a lawnmower engine. Tiny stems, small heads. The car had an ECU to make sure that fuel mixtures stayed within limits to avoid burning, but this engine had a carb with a mixture control, a formula pretty much guaranteed to cause trouble. You can't fly it like a Lycoming. To be safe you really need that ECU and all the harness and sensors and stuff, and there were many pounds of it. That Soob needed the full-size radiator to reliably cool it in an extended full-throttle climb, and I had fun designing the plenum for that, too, all inside the cowl. It worked.
 
The funny thing about the horizon is that it never seems to get any closer…..
 
Dan Thomas, your argument seems to suggest a distant kinship with both Ned Ludd and Joe Stalin.

Statistics: If we had well-researched data based on investigatory findings that accurately pinpointed the causal factors for each and every engine failure event, we might be able to make some definitive conclusions. I do not know of such a source. But we do know that NTSB investigations of accidents that occurred during a ten-year span beginning in 2012 cited powerplant failure as the principal cause of 2050 of those accidents, and further, that 214 of those accidents resulted in one or more fatalities. Dan Thomas, your attempt to dismiss those accidents as being statistically insignificant seems to me cynical and callous, and brings to mind a statement often attributed to Josef Stalin and paraphrased thusly: A single death is a tragedy, but a million deaths is a statistic. To me, (especially) as an aviator, each and every person who perishes (or is gravely harmed) in an aviation accident is a tragedy. Each and every one, regardless of cause. They who perished were not statistics—they were fellow humans whose lives had value and who left friends, families, and loved ones behind to grieve their loss. If you do not appreciate this perspective nothing I can say will matter, so I'll simply summarize my position thusly: I propose that better engines would have prevented many, and maybe most, of those accidents. A modern GA engine design should eliminate most of the failure modes/points that typically result in powerplant failures, reduce and simplify maintenance required for continued airworthiness, increase robustness throughout all flight operations, and simplify operation. That new airplanes are still being delivered with engine designs that are little changed from the 1950s, is a [expletive deleted] shame.

Dan Thomas, while I could address other statements and questions that you made in post #40, it seems pointless to do so based on the above. However, there is one statement that you made that I take particular issue with:
Well, if a pilot cannot be taught to respect the engine, he's hopeless and will eventually learn the hard way.
You and I are gearheads and we have a particular affinity for the care, feeding, and operation of our engines. But, do we fly the airplane so that we can operate the engine, or do we operate the engine so that we can fly the airplane? I don’t know about you, but the aspect of flying that I most enjoy is FLYING, and the less tedious engine management that I have to do, the more I can enjoy slipping the surly bonds of Earth. It’s worth noting that some of the most memorable flights that I’ve ever had were experienced in airplanes that have no engine at all. But there’s another important reason to make aircraft engines simpler to operate: safety. One thing that flying teaches us is that we humans are not as good at multi-tasking as we like to believe, and the more that we reduce pilot workload, the more brain cells we free-up to make good, timely decisions and competently execute them. A single-lever power control, connected to an engine that manages itself, allows the pilot to command the required/desired engine power with a single swift action and then focus on flying the airplane without being distracted by engine management requirements. Channeling your inner Ned Ludd, you continued...
Do we need antiskid brakes so the pilot doesn't blow the tires out?
Yes, we need antiskid brakes and they are long overdue. Every competent pilot can bring a 172 to a stop on dry pavement without locking a wheel, but obtaining maximum available braking effectiveness on a traction-compromised surface is another thing altogether, and it’s a thing that is rarely—if ever—taught.

Dinosaurs--your local GA airport has more of them than Jurassic Park.
 
I suppose "too many" is in the eye of the beholder. Regardless, let's just say that yes, 77 (or 200 or whatever) powerplant incidents per year is too many.
We agree--there are too many accidents (not incidents, accidents).

Exactly how do you envision "modern engines" will solve that problem?
As stated in the post above, by producing engines that are more robust with components less likely to fail, that require less maintenance, and that are simpler to operate.

Let's just say that we can snap our fingers and instantly generate a perfect engine today. Let's even say that we can snap our fingers and make the development cost = zero. We're just going to replace the engines in current-production light piston singles (and twins?) with this perfect new engine without changing the base price of the aircraft. And lets outlaw the sale of legacy engines, for good measure.

How long would it take before these new planes become a significant enough fraction of the flying fleet of light aircraft before it would have any measurable effect on annual powerplant related failures?
Oh if only a finger-snap could do it... Clearly a significant improvement would take a decade or more. That doesn't mean that we shouldn't do it.

Of course, holding the aircraft price constant with the new engine is ridiculous--it would take 10s or 100s of millions of dollars to accomplish this new engine development, and those costs are by necessity going to drive up the price of the aircraft. Now, factor in the increased sales prices and ask the same question?

Like it or not, our dinosaur engines are going to be around for a long time (if there is fuel available to run them on). Especially since the business case for new engine development just doesn't work.
Once again we agree. This brings us back to my first post on the topic:
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.
 
We agree--there are too many accidents (not incidents, accidents).
We agree that the accidents are unfortunate.

Oh if only a finger-snap could do it... Clearly a significant improvement would take a decade or more. That doesn't mean that we shouldn't do it.
...
Once again we agree. This brings us back to my first post on the topic:
We do not agree that pursuing exorbitant expenditures to prevent those 77 or 200 (or whatever) engine failures is a good use of resources. You say it should be done but agree that there's no money to do it. So who do you propose should pay for it? The government?

There are many things in this world that kill people. Cancer, drunk drivers, sober drivers, opiod abuse, lack of access to affordable medical care, etc. A few hundred million dollars to save a few hundred lives of people mostly in pursuit of a hobby is not an effective investment compared to other opportunities to save lives. This argument is silly.
 
But we do know that NTSB investigations of accidents that occurred during a ten-year span beginning in 2012 cited powerplant failure as the principal cause of 2050 of those accidents, and further, that 214 of those accidents resulted in one or more fatalities.
Well, we started with 77 fatal accidents, then it was 214 fatals, now it's 2050 total. Maybe we should stretch the timeline back to 1903 to get some really startling figures to prove we must come up with better powerplants.

You did not address the Lycoming iE2 I posted, nor the SMA, nor the Austro. All modern designs. We "should" build better engines? Yeah, and we "should" stop all auto accidents by making cars totally idiot-proof, too. "Should" and "can" are two very different things, and we cannot now build far better engines and still be able to afford them. Lycoming sells very few iE2s and SMA's engines are rare indeed. The only one I ever encountered was the one I worked on. Even then, nice new designs like that will still fail if the pilot runs out of fuel, a common thing, or is too cheap to keep it maintained.

Here are some articles on the reasons for engine failure. You'll note that almost all are due to incompetence or stupidity on the part of the pilot, and I think we can admit that such pilots might be better off staying on the ground.

https://www.aviationsafetymagazine.com/features/why-engines-fail/

https://www.avweb.com/flight-safety/accidents-ntsb/why-engines-quit-failures-are-avoidable/

An excerpt from that second article:

Mechanical failure persistently accounts for about 15 percent of all crashes in general aviation, but not all mechanicals are engine related. Let’s put the standard risk metric on it. In 2016—the most recent year for which we have complete data— engine-related accidents amounted to 0.21 accidents per 100,000 flight hours, which is about 25 times lower than the overall accident rate. And considering that up to half of all engine failures are avoidable human-induced calamities, the risk could be even lower than that. But to avoid doing the stupid stuff, you have to know what the stupid stuff is and that’s what we’re covering here.

Engine failure accidents are 0.21 per 100,000 flight hours. That means, on average, you would have to fly 476,000 hours before you had an engine failure accident. I don.t think I could drive for half a million hours before my car quit for some reason.

That second article also pointed out that accidents often happen after engine failure due to pilot error in the forced landing. They'll often try to turn back to the runway, or try to stretch the glide to reach the airport to save the airplane, or get preoccupied with trying to restart the engine instead of flying the airplane all the way to the landing, whatever that landing looks like. Stalling and spinning in kills way more folks than crashing under control. Again, incompetence.

AOPA did a study maybe 20 years ago. The causes, in order of most common to least, looked like this:

1. Carburetor Ice
2. Fuel Starvation
3. Water in the fuel
4. Practice Forced landings (factors include cold engine, carb ice)
5. Oil starvation

Carb ice was, by far, the most common cause. NTSB often finds "nothing wrong" with an accident engine, and many of those engines are carbureted. Any ice that caused the failure is long gone by the time they get to the airplane, so they cannot blame carb ice, but they will say that "conditions at the time were conducing to carb icing."

Fuel injection systems fixed that long ago, but that system costs more money. Despite that, most new aircraft now are fuel-injected. Some legacy designs like the Aviat Husky, or the Citabrias, still sport carbs, to keep the airplane as affordable as possible. Anyone buying one needs to read the POH/AFM and learn from it and avoid the dumb failures. But so many won't do that.

Fuel starvation (or exhaustion) is just another dumb mistake. It happens way too often. Water in the fuel is inexcusable. Poor maintenance of fuel caps and a lack of diligent sumping is responsible for that. Most Mogas has ethanol in it now, and it absorbs water and takes it through the engine harmlessly. Before that, water often caused car trouble. Ethanol cannot be used in aircraft engines. They weren't designed to handle it, nor were their fuel systems.

Practice forced landings sometimes turn into the real thing. The POH/AFM is full of advice about that, yet it still happens. People are lazy. Oil starvation is also another stupid thing. Failing to check the oil, or failing to maintain those oil hoses, does it.

Pilots have been dumbed down by all the automatic stuff in their cars, and so now they blame the old tech in the airplane for their problems. Somehow now it's the aircraft and engine manufacturers' fault. This is completely consistent with the attitude of current generations: It's always someone else's fault.

I'm not a Luddite. I have been in aviation for 50 years. It has made me a realist. Commercial pilot, aircraft maintenance engineer. I have seen numerous attempts at new engines. I have watched the agonies that those folks go through, the vast amounts of money they spend on it. And I have watched flight training get weaker and weaker as young instructors pass on their ignorance to the students. The FIRST thing that needs to be addressed is pilot competence. Without that, they will find many ways to wreck the airplane. Period.

And the pitiful stuff I have found, as a mechanic, on airplanes owned by cheapskates has given me a real clear idea of what sorts of pilots crash when the engine quits.

If you know of a way to build a much better engine, show us. But I don't think you're an engineer or mechanic or homebuilder of engine conversions at all. It's real easy to criticize, much harder to offer workable solutions. This is not a new attitude; we encounter it regularly here and over on HBA. Building a better engine that doesn't cost far more than what we have has already been shown to be impossible.
 
We agree that the accidents are unfortunate.
My mistake: when you wrote...
Regardless, let's just say that yes, 77 (or 200 or whatever) powerplant incidents per year is too many.
...I understood you to mean that there are too many. That they are unfortunate goes without saying.

We do not agree that pursuing exorbitant expenditures to prevent those 77 or 200 (or whatever) engine failures is a good use of resources.
Very well--we will disagree. I think having engines that are more reliable, efficient, and easier to maintain and operate, is a fantastic use of resources. Funding for development should be connected to the ROI prospects, but I would not object to government funding--especially since the government is one factor that affects certification costs. As has been previously suggested, potential funding sources seem to be more interested in electric propulsion. At least, that's how it was a few years back when I was involved in GA fundraising. Have you considered the total cost that GA incurs as a result of accidents?

There are many things in this world that kill people. Cancer, drunk drivers, sober drivers, opiod abuse, lack of access to affordable medical care, etc. A few hundred million dollars to save a few hundred lives of people mostly in pursuit of a hobby is not an effective investment compared to other opportunities to save lives. This argument is silly.
Spoken like a true actuary, but the logical pursuit of this line of reasoning leads down a road that we might not want to travel.
 
Well, we started with 77 fatal accidents, then it was 214 fatals, now it's 2050 total. Maybe we should stretch the timeline back to 1903 to get some really startling figures to prove we must come up with better powerplants.
Your summary is a misrepresentation.

...

Dan Thomas, I began addressing your post on a point-by-point basis, but abandoned the effort as an exercise in futility. As I pointed-out (pun intended) in a previous post (alliteration unintended), your arguments seem to boil down to a variation of the everyone-is-an-idiot-(except-me) theme, and that's a mindset that tends to be impervious to different perspectives.

Who are we to judge just who is a stupid, incompetent idiot? A lot of accidents are caused by stupid mistakes, but many stupid mistakes are made by smart, competent, experienced, and well-intended, people. The inquiry into why this is so, and how to reduce such seemingly inexplicable occurrences of human error, is perhaps the greatest contribution to airline safety since the jet engine. A little humility if you please, sir.

I don't think you're an engineer or mechanic or homebuilder of engine conversions at all.
Well, you got two out of three.

It's real easy to criticize, much harder to offer workable solutions. This is not a new attitude; we encounter it regularly here and over on HBA.
Referring to pilots involved in mishaps as being stupid, idiots, incompetent, weak, etc. sure sounds like criticism to me, criticism that fails to offer workable (or any) solutions. And it's certainly not a new attitude on this board or other boards; it is an attitude that predates the internet by about eight decades.

Getting back to the point, none of your arguments contradict the characterization of GA engines as being dinosaurs. In fact, some of your statements rather strongly support that perspective.
 
none of your arguments contradict the characterization of GA engines as being dinosaurs.
And it can be said none of your arguments prove GA engines are dinosaurs. If you're truly concerned for the loss of life as you state above, then your efforts would be centered on who controls those GA engines as there lies the root cause of most aircraft fatal accidents. Even most fatal engine failures are a result of operational issues and not design issues. The data for this is out there if you choose to look for it. But to keep on topic you have yet to point out which specific engine model(s) from the “plethora of ICE designs” out there you personally think will eclipse the safety record of the current design used in GA aircraft?
 
Well, you got two out of three.

So which one is correct? Your arguments would carry more weight with bona fides, otherwise you’re just another internet warrior with an unqualified opinion. Which you might have noticed doesn’t carry any weight on this forum.

Now having established your position, what exactly would you have us do? You might be 100% correct in your assessment, but as I and others have stated a practical and affordable solution is not currently available. So now tell us, what’s the plan to save us luddites from ourselves?
 
My mistake: when you wrote...
Regardless, let's just say that yes, 77 (or 200 or whatever) powerplant incidents per year is too many.
...I understood you to mean that there are too many.
I also said, "Let's just say that we can snap our fingers and instantly generate a perfect engine today." Did you think I now had such an engine in my living room, as well?

You omitted the rest of what I said: "I suppose 'too many' is in the eye of the beholder." I obviously meant, "OK, let's say for the sake of argument that's true," not, "This is absolutely true." Willful misunderstanding is not an admirable way to pursue an argument.

Have you considered the total cost that GA incurs as a result of accidents?
If I did, I would focus more on trying to get people to not fly VFR into IMC and into terrain and run out of fuel, since those events occur far more frequently than engine or other mechanical failures.

Spoken like a true actuary, but the logical pursuit of this line of reasoning leads down a road that we might not want to travel.
Yes, when anything is taken to extremes it can become a big problem. But when considered reasonably, it is a reasonable statement.

Are you looking to save lives? Or are you looking to make a better engine for the sake of a better engine? If the former, this is about the least effective way of going about it. If the latter, then okay, but what is the benefit of the "better engine"? Higher purchase prices for new aircraft today, and 30 years from now maybe 175 engine failures per year instead of 200?

Either way, it's no mystery why there are no major efforts to transform the installed base of piston engines.
 
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Referring to pilots involved in mishaps as being stupid, idiots, incompetent, weak, etc. sure sounds like criticism to me, criticism that fails to offer workable (or any) solutions. And it's certainly not a new attitude on this board or other boards; it is an attitude that predates the internet by about eight decades.

I was just watching some videos of crashes and spinouts on Minnesota highways in the last three days. Most drivers are proceeding cautiously and they get through OK. Some are impatient and pass others and spin out as they try to steer on ice. Some just blast pass slow-moving cars without thinking about why those cars are moving so slowly. And many, many drivers are not out there at all because they checked the weather and heeded warnings from the highways people to stay home if they didn't absolutely have to go out.

Incompetence and arrogance are everywhere. It's as common in aviation as it is in driving, but because aviation is so much more unforgiving, it's more deadly. In 50 years I have seen my share of it; it's as obvious as it can be. Yet there are people who get all torqued up when this is pointed out. I remind them that these cars spinning out and crashing are all equipped with ABS and many also have stability augmentation, some are four-wheel-drive, and yet their drivers manage to bust them up. They're either incompetent, or they're oblivious to the conditions, and the car's doodads can't save them. An idiot-proof aircraft engine will similarly not save the careless; they'll manage to outwit it. And that engine will cost two or three times as much money, too. Only rich idiots will own them.
 
And it can be said none of your arguments prove GA engines are dinosaurs. ... But to keep on topic you have yet to point out which specific engine model(s) from the “plethora of ICE designs” out there you personally think will eclipse the safety record of the current design used in GA aircraft?
You got me there, Bell206—I have absolutely no proof that GA engines are, factually, dinosaurs. Dinosaurs, as you know, were reptilian animals that roamed the planet a couple-hundred million years ago, give or take few million.

I chose to characterize GA engines as dinosaurs, not define them as such. A characterization is not a hypothesis to be tested for validity or a theorem with proofs—it’s a rhetorical device, a hyperbolic simile if you will, and, in the context of the exchange with Dan Thomas, a dysphemism.

As for engines (and since you insist), some engines that interest me, spanning a range of size and complexity: RED (certificated); D-Motor (in production, not certificated); and EPS (development currently suspended due to funding). An honorable mention goes to DeltaHawk, the perennial just-around-the-corner, always almost ready for certification, 2-stroke diesel. You are surely familiar with these engines and have your own opinions regarding their merits or lack thereof. Regardless of which design we consider, the crucial matter is how the design is realized, and that will determine whether it will allow us to retire our dinosaurs to museums. But I’m most intrigued by ceramic technology and its potential to enable the manufacture of small, lightweight, fuel-efficient gas turbines. Ceramic Matrix Composite (CMC) development has been ongoing since at least the late 1970s. At that time, CMC turbine blisks were not durable enough for use in aviation applications, but some engineers predicted that ongoing development would produce gas turbines that could replace conventional piston engines in GA by 2000. Obviously that was optimistic, but CMC research and development has continued and matured. This technological development is being funded by commercial (airline) and military engine applications, based on the potential to greatly increase their efficiency and reliability (and perhaps at a lower cost compared to expensive alloys currently used). The technology may be advanced enough, now, to build a compact, powerful, fuel-efficient turboprop powerplant for GA use. At what cost, I cannot guess, but the production scale for the technology would be shared with the military and commercial engine market, which may soon make it affordable enough for GA. Or not.
 
I also said, "Let's just say that we can snap our fingers and instantly generate a perfect engine today." Did you think I now had such an engine in my living room, as well?
You omitted the rest of what I said: "I suppose 'too many' is in the eye of the beholder." I obviously meant, "OK, let's say for the sake of argument that's true," not, "This is absolutely true." Willful misunderstanding is not an admirable way to pursue an argument.
Well, I did admit that it was my mistake.

If I did, I would focus more on trying to get people to not fly VFR into IMC and into terrain and run out of fuel, since those events occur far more frequently than engine or other mechanical failures...Are you looking to save lives? Or...
If you're truly concerned for the loss of life as you state above, then your efforts would be centered on who controls those GA engines as there lies the root cause of most aircraft fatal accidents.
That's like saying that we shouldn't invest in cancer treatment because heart disease kills more people. You're both just being argumentative, but this is an internet forum so...

Either way, it's no mystery why there are no major efforts to transform the installed base of piston engines.
Seems we are all in agreement here, at least.
 
I was just watching some videos of crashes and spinouts on Minnesota highways in the last three days. Most drivers are proceeding cautiously and they get through OK. Some are impatient and pass others and spin out as they try to steer on ice. Some just blast pass slow-moving cars without thinking about why those cars are moving so slowly. And many, many drivers are not out there at all because they checked the weather and heeded warnings from the highways people to stay home if they didn't absolutely have to go out.

Incompetence and arrogance are everywhere. It's as common in aviation as it is in driving, but because aviation is so much more unforgiving, it's more deadly. In 50 years I have seen my share of it; it's as obvious as it can be. Yet there are people who get all torqued up when this is pointed out. I remind them that these cars spinning out and crashing are all equipped with ABS and many also have stability augmentation, some are four-wheel-drive, and yet their drivers manage to bust them up. They're either incompetent, or they're oblivious to the conditions, and the car's doodads can't save them. An idiot-proof aircraft engine will similarly not save the careless; they'll manage to outwit it. And that engine will cost two or three times as much money, too. Only rich idiots will own them.

Dan Thomas, you disagreed with my characterization of GA engines as being like dinosaurs and took it upon yourself to re-educate me. You took the time to cite magnetos (a 19th Century device) and carburetor ice (the MA-3 and MA-4 are essentially a 1920s tractor carburetor with an adjustable mixture control). But mostly, your rebuttal consists of your opinion that people are idiots. GA engines are not dinosaurs, because people are idiots (other people, of course). So, is that the only wrench in your toolbox, or what?

This discussion reminded me of the Continental Tiara. You've been in the business for 50 years (congratulations, BTW, and I mean that sincerely), so you undoubtedly recall the ill-fated Tiara. A search turned-up very few hits for the Tiara, but it was mentioned in an AOPA column by Mike Busch (click on the blue words to follow the hyperlink). Busch makes interesting observations related to this topic. You may note that he characterizes current GA engines as "Jurassic." Kinda like dinosaur, yes? Ah, but what does he know...

Interestingly, the other-people-are-idiots mindset is one of the logical fallacies that puts us in danger of becoming idiots ourselves. When we assume that accidents happen because the other guy is/was an idiot, it fosters the assumption that it can't happen to us because, after all, we are not idiots, which in turn promotes a tendency to overlook or underestimate risks and potential threats while overestimating our own abilities. This syndrome can be linked to Dunning-Kruger, in a general sense.

Well, Dan Thomas, this has been a casual and amusing conversation, but it seems that we've exhausted the potential to learn something from it. So, to conclude, you continue to not be an idiot, and I (being an idiot) will hold your beer.
 
I chose to characterize GA engines as dinosaurs, not define them as such.
But you also chose to state that these “older” engines were dangerous by design and needlessly killed unsuspecting people and there were a “plethora of ICE” that were safer. However, the fact is you have zero replacement engines to offer except a handful of unproven designs with an unknown failure rate.
Dinosaurs = 1; SGOTI = 0

Regardless of which design we consider, the crucial matter is how the design is realized, and that will determine whether it will allow us to retire our dinosaurs to museums.
No market, no retirement. Same issue for all the other new technologies out there that will basically never make it to the private owned, recreational aircraft market. There is no market nor has there been since the mid-90s.

The technology may be advanced enough, now, to build a compact, powerful, fuel-efficient turboprop powerplant for GA use.
Unfortunately there is no true “fuel-efficient” turboshaft/prop engine by the simple fact of how it makes its power. However, the micro-turbine technology has been there for years and has made a huge surge in recent times. There are even flying hybrid turbines that will combine electrical propulsion in concert with an ICE. The difference is the ICE uses 100% SAF. Will these current turbines trickle down to the TC private market? Possibly. Some current turbines produce enough HP/kW to power a small conventional aircraft with a few installed on E/ABs. So maybe, just need to see if there is… wait for it... a market for the conversion.

That's like saying that we shouldn't invest in cancer treatment because heart disease kills more people. You're both just being argumentative,
Not at all. There have been millions invested over the years to not only design updated engines but aircraft as well. Hundreds of millions actually. For example, look at the FAA/NASA AGATE program which brought you the Columbia and Cirrus new generation private/recreational aircraft. The problem was the masses preferred their "dinosaur" engines and aircraft over the new stuff. And it was cheap by todays standards. So if the majority of people do not want to be "cured" why should anyone else spend a nickel on a new "treatment'? The only argument here is you don't want to believe those facts. It is what it is.;)
 
But I’m most intrigued by ceramic technology and its potential to enable the manufacture of small, lightweight, fuel-efficient gas turbines. Ceramic Matrix Composite (CMC) development has been ongoing since at least the late 1970s. At that time, CMC turbine blisks were not durable enough for use in aviation applications, but some engineers predicted that ongoing development would produce gas turbines that could replace conventional piston engines in GA by 2000. Obviously that was optimistic, but CMC research and development has continued and matured. This technological development is being funded by commercial (airline) and military engine applications, based on the potential to greatly increase their efficiency and reliability (and perhaps at a lower cost compared to expensive alloys currently used). The technology may be advanced enough, now, to build a compact, powerful, fuel-efficient turboprop powerplant for GA use. At what cost, I cannot guess, but the production scale for the technology would be shared with the military and commercial engine market, which may soon make it affordable enough for GA. Or not.
There are more fact of physics that will defeat this. Small turbines have never been fuel-efficient, and never will be. Their tiny rotors suffer the same losses that tiny propellers do. Small areas due to their size, many tip losses, enormously high RPM. They are used in many helicopters and some airplanes due entirely to their reliability, smooth operation, long life, and light weight. They sure aren't used to save fuel. They burn way more fuel than a piston engine of equivalent horsepower. The specific fuel consumption of the Rolls/Allison 250 series used in the Bell 206, for example, is quoted at .697 pounds of fuel per horsepower per hour. 450 HP or so. Contrast that with the SFC of the typical "dinosaur" engine of around .400.

It won't matter what the engine is made of, either. The losses are still there. The big airliner engines are MORE efficient than the piston engine due to the large rotors that give them their efficiency. Big turboprops, much smaller than the huge airliner jets, still burn as much than a piston, around .400 SFC as in the GE 38. 7500 HP.
 
Dan Thomas, you disagreed with my characterization of GA engines as being like dinosaurs and took it upon yourself to re-educate me. You took the time to cite magnetos (a 19th Century device) and carburetor ice (the MA-3 and MA-4 are essentially a 1920s tractor carburetor with an adjustable mixture control).
The piston internal combustion engine is also a 19th century device dating from the 1830s. I guess we need to throw it out, too.

The "modern" electronic ignitions for aircraft are magnetos with electronic switching in place of the points, and they have electronic spark advance as well. But they still generate their power the same way as the magneto of old: spinning a magnet inside an armature wrapped with a coil of copper wire. The same idea as the alternator in your brand-new car, the generators at the power plant, and so on. But, like I told you once already, those certified electronic ignitions have been suffering failures that old magnetos didn't. The heat and vibration shakes and bakes them. My 1946 magnetos still make a very hot spark and do so reliably if they're properly maintained. Hard to beat that, especially against expensive electronic stuff that fails without warning. Mags almost always warn you in advance that they need work.

Aircraft electronic ignition needs to be mounted away from that engine, to protect those sensitive components. Making an electronic mag just isn't going to cut it. Not yet, anyway.

Just because something dates back a long time does not make it obsolete if there is nothing affordable and reliable to replace it. We're still using fire to propel our machines, aren't we? Caveman technology.
 
But you also chose to state that these “older” engines were dangerous by design and needlessly killed unsuspecting people...
Actually, that’s your interpretation of what I said. It's not worth revisiting.
However, the fact is you have zero replacement engines to offer except a handful of unproven designs with an unknown failure rate.
Dinosaurs = 1; SGOTI = 0
So, you’re saying that any potential replacement engine must have established a 70-year service history before it can be considered as a candidate. If that’s the rule, the game is rigged and the dinosaurs win by default.
No market, no retirement. Same issue for all the other new technologies out there that will basically never make it to the private owned, recreational aircraft market. There is no market nor has there been since the mid-90s.
It seems that everyone is in agreement with regard to market considerations, which I have acknowledged several times.
Unfortunately there is no true “fuel-efficient” turboshaft/prop engine by the simple fact of how it makes its power.
You don’t say. In hopes of steering this conversation towards something more informative and interesting, tell me about this “simple fact of how it makes its power.”
Not at all. There have been millions invested over the years to not only design updated engines but aircraft as well. Hundreds of millions actually. For example, look at the FAA/NASA AGATE program which brought you the Columbia and Cirrus new generation private/recreational aircraft. The problem was the masses preferred their "dinosaur" engines and aircraft over the new stuff. And it was cheap by todays standards. So if the majority of people do not want to be "cured" why should anyone else spend a nickel on a new "treatment'? The only argument here is you don't want to believe those facts. It is what it is.;)
How many times would you like me to acknowledge the role that market forces play in new powerplant development and implementation, before you acknowledge that we agree on this aspect of the matter? Nevermind—I’m more interested in how turbine engines make power, and how that relates to fuel efficiency.
 
There are more fact of physics that will defeat this. Small turbines have never been fuel-efficient, and never will be. Their tiny rotors suffer the same losses that tiny propellers do. Small areas due to their size, many tip losses, enormously high RPM. They are used in many helicopters and some airplanes due entirely to their reliability, smooth operation, long life, and light weight. They sure aren't used to save fuel. They burn way more fuel than a piston engine of equivalent horsepower. The specific fuel consumption of the Rolls/Allison 250 series used in the Bell 206, for example, is quoted at .697 pounds of fuel per horsepower per hour. 450 HP or so. Contrast that with the SFC of the typical "dinosaur" engine of around .400.

It won't matter what the engine is made of, either. The losses are still there. The big airliner engines are MORE efficient than the piston engine due to the large rotors that give them their efficiency. Big turboprops, much smaller than the huge airliner jets, still burn as much than a piston, around .400 SFC as in the GE 38. 7500 HP.
Yes, the C250 is no gold medalist in terms of fuel efficiency, compared to piston engines.

Per your previous post, maybe we can discuss the fluid dynamics of impellers and actuator disks later, depending on Bell206's contribution. But for now, I would like to offer an alternative viewpoint of your comparison between a large turbofan and a GA piston engine. The GE115 turbofan, at a cruise TAS of 460 knots with a fuel burn of about 7700pph, has an approximate BSFC of about 0.12 lb/hp whereas that of a GA piston engine is about 0.04 lb/hp (I think you intended to type .0400 instead of .400). This comparison can only be considered an approximate relationship since there is no direct conversion between thrust (force), and hp (a unit of work accomplished) and my quick, informal calculations may be inaccurate. But it seems clear that the GA dinosaur wins this one by a wide margin.
 
Actually, that’s your interpretation of what I said. It's not worth revisiting.
No, they were your words.
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.



which I have acknowledged several times.
You've acknowledged it but your comments show you don't believe it.

So, you’re saying that any potential replacement engine must have established a 70-year service history before it can be considered as a candidate.
Not at all. But the potential replacement needs to get off the drawing board or at least installed in more than one aircraft. I know of several certified GA recip engines that were never installed and the TC was surrendered.

You don’t say. In hopes of steering this conversation towards something more informative and interesting, tell me about this “simple fact of how it makes its power.”
Good. I was getting tired of going around in circles. In general, turboshaft engines unlike turbofan engines have no way of increasing power output without increasing fuel flow. There was a design change on the power turbine side many years ago that did increase fuel efficiency but at a performance cost. The engine fuel burns went from approx. 60 gal/hr with a fixed turbine design, down to around 38-40 gal/hr with a free turbine design. Even with FADEC installed on a free turbine design the fuel efficiency remains comparatively the same and as larger aircraft were developed more power was needed and the fuel flows are simply increased to meet the demand. Over time the free turbine design became the design of choice but there still are fixed turbine engines working everyday.
 
Just because a technology is old doesn't mean it's automatically obsolete and should be replaced. Chainsaws exist and are very useful, but sometimes an ax is still the best tool for the job.
 
That's like saying that we shouldn't invest in cancer treatment because heart disease kills more people.
I think it's more like saying we shouldn't invest 100s of millions of dollars on people who fall off their bikes and get bitten by a rare poisonous spider while they're on the ground. It's awful when it happens, and we could probably reduce the numbers, but...is it really a big enough problem in the grand scheme of things? You think it is. I don't. Regardless, nobody's going to spend millions to save a few poisoned bikers.
 
The GE115 turbofan, at a cruise TAS of 460 knots with a fuel burn of about 7700pph, has an approximate BSFC of about 0.12 lb/hp whereas that of a GA piston engine is about 0.04 lb/hp (I think you intended to type .0400 instead of .400).

I said 0.400 and I meant 0.400.

A Lycoming O-320 , at 2000 feet ASL, standard temperature and pressure, and at 2550 RPM generates 80% of its 150 HP, or 112.5 HP, and burns 8.2 US GPH doing that. 8.2 US gallons, at 6.01 pounds per gallon, is 49.3 pounds per hour. Dividing that 49.3 by 112.5 HP gives us an SFC of 0.438 pounds per HP per hour. Here's the cruise chart for a Cessna 172M, which has an O-320-E2D engine of 150 HP:

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I wish it was 0.0400 pounds per hour. That would make that engine burn less than a gallon per hour in cruise. Much too good to be true.
 

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I said 0.400 and I meant 0.400.

I wish it was 0.0400 pounds per hour. That would make that engine burn less than a gallon per hour in cruise. Much too good to be true.
Ah, see there? Like I said, I'm the idiot, holding your beer. The decimal error was my own, and led me to recheck my earlier figure for the GE90-115. I tried a few different cruise scenarios and came up with (approximate) 0.125 to 0.181. But as you can see, my calculations are suspect.
 
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