piston aircraft engine techlology lag (?)
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piston aircraft engine techlology lag (?)
Why is it, now I understand this may be somewhat debatable, but why is it that piston engine technology in aircraft is light years behind automotive engine technology? A brand new Cessna 162, for example (maybe not the best example) comes with 1950's engine technology...a push-rod air cooled carburetor fed very basic engine that needs to be completely taken apart every 2,000 hours and re-built. Its fuel economy is horrible by today's standards.
I purchased a new 1997 Toyota (not trying to start and kind of brand war here) truck with a 150 HP fuel injected engine. I never once "pre-flighted" this engine, nor had its oil analyzed, nor changed its oil every 50 hours, nor had it scoped or inspected once a year. (Note that I am NOT saying that pre-flighting an aircraft engine is wasted time or should simply go away.) Not once in the 150,000 miles I drove the truck did it simply stop working or even lose power. The day I sold the truck it still purred like a kitten. Fuel economy was great. Today it's even better. I did not have to play with its mixture as the mass airflow sensor and computer took care of this for me. Didn't much worry about carb icing either. It was water cooled, but not once did all the coolant simply leak out causing an overheating situation. This little engine just did its job and kept to itself for 150,000 miles and the only maintenance I did to it was 5,000 mile oil changes.
Why can't Cessna, for example, use an engine like this in their light aircraft? Granted, I do fully understand that aircraft engines, unlike auto engines, are run at 100% power MUCH more often, however that aspect could easily be overcome by simply de-rating an auto engine...for example de-rate that 150HP to 110 HP...or more aggressively de-rate a 175 HP to 110 HP.
Think of the advantages of doing something like this:
1. greatly decreased initial engine purchase price. (granted, a converted auto engine would require more quality control than one used in an actual auto)
2. greatly improved fuel economy
3. goodbye 100LL. Run 94 or even 87 MOGAS
4. increased reliability and safety
Unless someone explains to me why this simply wouldn't work, I am running under the assumption that it absolutely would. In fact, there is a company that is doing just this...I believe with a Ford engine. Said company is also out to make piston aviation much quieter as well, running low RPM high output props (simply taking a much more aggressive bite with a prop that runs at a lower RPM).
Granted I am no aviation expert, but I think that automotive engine technology in light aircraft would be a BIG contributor to enabling many more of us to afford our own aircraft as the engine and its maintenance is such a large component of the cost of buying and owning an aircraft. Thoughts? Thanks for any replies.
I purchased a new 1997 Toyota (not trying to start and kind of brand war here) truck with a 150 HP fuel injected engine. I never once "pre-flighted" this engine, nor had its oil analyzed, nor changed its oil every 50 hours, nor had it scoped or inspected once a year. (Note that I am NOT saying that pre-flighting an aircraft engine is wasted time or should simply go away.) Not once in the 150,000 miles I drove the truck did it simply stop working or even lose power. The day I sold the truck it still purred like a kitten. Fuel economy was great. Today it's even better. I did not have to play with its mixture as the mass airflow sensor and computer took care of this for me. Didn't much worry about carb icing either. It was water cooled, but not once did all the coolant simply leak out causing an overheating situation. This little engine just did its job and kept to itself for 150,000 miles and the only maintenance I did to it was 5,000 mile oil changes.
Why can't Cessna, for example, use an engine like this in their light aircraft? Granted, I do fully understand that aircraft engines, unlike auto engines, are run at 100% power MUCH more often, however that aspect could easily be overcome by simply de-rating an auto engine...for example de-rate that 150HP to 110 HP...or more aggressively de-rate a 175 HP to 110 HP.
Think of the advantages of doing something like this:
1. greatly decreased initial engine purchase price. (granted, a converted auto engine would require more quality control than one used in an actual auto)
2. greatly improved fuel economy
3. goodbye 100LL. Run 94 or even 87 MOGAS
4. increased reliability and safety
Unless someone explains to me why this simply wouldn't work, I am running under the assumption that it absolutely would. In fact, there is a company that is doing just this...I believe with a Ford engine. Said company is also out to make piston aviation much quieter as well, running low RPM high output props (simply taking a much more aggressive bite with a prop that runs at a lower RPM).
Granted I am no aviation expert, but I think that automotive engine technology in light aircraft would be a BIG contributor to enabling many more of us to afford our own aircraft as the engine and its maintenance is such a large component of the cost of buying and owning an aircraft. Thoughts? Thanks for any replies.
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Here is the company I was talking about:
Quiet Aviation - Experimental Aircraft and Powerplant Research, Design and Manufacturing
They are using a GM motor.
So using a 2011 model electronically controlled FI engine would not lead to any fuel burn reduction? Interesting.
Quiet Aviation - Experimental Aircraft and Powerplant Research, Design and Manufacturing
They are using a GM motor.
So using a 2011 model electronically controlled FI engine would not lead to any fuel burn reduction? Interesting.
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Plasmec I think you at least partially answered your own questions viz:
Oil change every 5000 miles is = to 50 hours @ 100mph
A 2000 hr TBO = 200,000 miles so will your car engine do that without a proper inspection. Well yes maybe but then if it fails you can (hopefully) just pull over.
etc etc
Oil change every 5000 miles is = to 50 hours @ 100mph
A 2000 hr TBO = 200,000 miles so will your car engine do that without a proper inspection. Well yes maybe but then if it fails you can (hopefully) just pull over.
etc etc
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You're basically describing the Rotax 912, used on plenty of homebuilt aircraft, microlights and until recently the Piper sport (now back to sportscruiser).
It is part water cooled part aircooled, with 2 radiators which only occasionally leak. Runs upto 6000 rpm, with a fixed ratio gear box so the propeller can make good use of it. 100HP and only 12 litres an hour fuel burn, and runs very happily on the same petrol you put in your car.
If it's a home build, you don't even need to strip it at 2000 hours.
Ultimately, there is more to go wrong with a radiator and gearbox to worry about, and the high revs over time will take the toll, but with a lower outlay to buy the engine, lower fuel costs and overall lower maintenance it seems to be the way a lot of manufacturers are going.
It is part water cooled part aircooled, with 2 radiators which only occasionally leak. Runs upto 6000 rpm, with a fixed ratio gear box so the propeller can make good use of it. 100HP and only 12 litres an hour fuel burn, and runs very happily on the same petrol you put in your car.
If it's a home build, you don't even need to strip it at 2000 hours.
Ultimately, there is more to go wrong with a radiator and gearbox to worry about, and the high revs over time will take the toll, but with a lower outlay to buy the engine, lower fuel costs and overall lower maintenance it seems to be the way a lot of manufacturers are going.
So using a 2011 model electronically controlled FI engine would not lead to any fuel burn reduction?
As a result nobody is eager to invest in a market that can never be big, and if a Thielert stands up and suffers a bit of bad luck the reluctancy and fear only increase. There have been plenty of beautiful new aircraft engines designed - as yet we are still waiting for the first to really break through.
edit@RTN11: 100 hp would be the 912S, which burns some 15 litres per hour rather than 12.
@WorkingHard: 100mph is way above the life-average speed of a car. 30mph would be much closer
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I find the 912 typically burns 12/hr rather than the book 15. Having spoken to many pilots and instructors who operate this engine, they all tend to agree that at around 4400rpm you get 12/hr (obviously with speed dependent on the airframe).
Also, with autolean, it is more like the theoretical engine described by the OP.
I'm a big fan of lycomings and continentals, but 100LL won't be around forever, so it's great that there are already alternatives emerging.
Edit
@Jan Olieslagers I think workinghard was making the point that an aircraft flying for 50 hours at around 100mph then having a service is the same at the OP's car being serviced at 5000 hours.
Also, with autolean, it is more like the theoretical engine described by the OP.
I'm a big fan of lycomings and continentals, but 100LL won't be around forever, so it's great that there are already alternatives emerging.
Edit
@Jan Olieslagers I think workinghard was making the point that an aircraft flying for 50 hours at around 100mph then having a service is the same at the OP's car being serviced at 5000 hours.
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The specific fuel consumption of a 912S is slightly worst than a Continental O-200 or Lycoming O-235. Real world consumption is slightly better - probably due to 'better' propeller efficiency. The Rotax typically turns the prop slower and uses thinner blades.
But there are a lot of poor details in the old engines - Lycomings camshafts are very vulnerable to corrosion if they are not run very frequently. The valve geometry is poor and so the valve wobble test' will frequency fail.
Both Lycoming and Continental have proved incapble of producing quality anf reliable crankshafts - for a vairety of differing reasons. Both have major issues with crankcase cracking, cylinder cracking and cylinder wear - again for differing reasons.
Operated carefully and rebuilt by people who really know what they are doing they can be reliable - the Rotax however is much closer to a car engine in terms of its tolerance to the way it is operated.
But there are a lot of poor details in the old engines - Lycomings camshafts are very vulnerable to corrosion if they are not run very frequently. The valve geometry is poor and so the valve wobble test' will frequency fail.
Both Lycoming and Continental have proved incapble of producing quality anf reliable crankshafts - for a vairety of differing reasons. Both have major issues with crankcase cracking, cylinder cracking and cylinder wear - again for differing reasons.
Operated carefully and rebuilt by people who really know what they are doing they can be reliable - the Rotax however is much closer to a car engine in terms of its tolerance to the way it is operated.
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Your car engine doesn't run at 65% power or above for most of the time. It probably weighs more per HP with radiator etc. Also it doesn't support the weight and precession forces of a propeller.
Also how much power does it produce at 2500rpm (or how much extra is the weight of a gearbox)
Most car engines don't last long when installed in aircraft, perhaps the VW and Subaru engines are the best examples but there are lots of conversion attempts that have failed.
So, I think your original premise is wrong.
A Lycoming these days can have fuel injection, electronic ignition, roller tappets and run on mogas. Further advances are allowed on homebuilt aircraft.
So perhaps you should be asking why certified aircraft can't have the same advances that homebuilt/experimental aircraft have.
Also how much power does it produce at 2500rpm (or how much extra is the weight of a gearbox)
Most car engines don't last long when installed in aircraft, perhaps the VW and Subaru engines are the best examples but there are lots of conversion attempts that have failed.
So, I think your original premise is wrong.
A Lycoming these days can have fuel injection, electronic ignition, roller tappets and run on mogas. Further advances are allowed on homebuilt aircraft.
So perhaps you should be asking why certified aircraft can't have the same advances that homebuilt/experimental aircraft have.
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Every car I've owned has had an engine failure (some more than one). So what, you pull into the side of the road and that's that. Admittedly this was slightly hairy from the outside lane of the A1(M) in heavy rain and heavy traffic, but I managed it.
No aircraft I've flown has had an engine failure.
No aircraft I've flown has had an engine failure.
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I have never had an engine just quit working. Not on a car (including my first jalopy) or even a lawn mower. This does not mean it can't happen in the air, but auto engines have come a long way. They are incredibly reliable.
As far as auto engines not being any more efficient than antiquated aircraft engines, I'm just not understanding this. Simply switching to fuel injection is a gain in efficiency right there as the fuel vaporizes better. Direct gasoline injection will be a lot better (although at the present time direct gas injection causes a lot of intake manifold fouling, a problem that needs to be figured out still). If 50 year old engines were just as efficient as today's engines, we wouldn't have spend all this time and money developing them over the years. We'd all be driving old carbureted, non-computerized pushrod engines in 2011.
As far as auto engines not being any more efficient than antiquated aircraft engines, I'm just not understanding this. Simply switching to fuel injection is a gain in efficiency right there as the fuel vaporizes better. Direct gasoline injection will be a lot better (although at the present time direct gas injection causes a lot of intake manifold fouling, a problem that needs to be figured out still). If 50 year old engines were just as efficient as today's engines, we wouldn't have spend all this time and money developing them over the years. We'd all be driving old carbureted, non-computerized pushrod engines in 2011.
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Why is it, now I understand this may be somewhat debatable, but why is it that piston engine technology in aircraft is light years behind automotive engine technology?
When was the last time you flew your car?
Is that an "ah-ha" moment I hear coming from your general direction?
Direct gasoline injection will be a lot better (although at the present time direct gas injection causes a lot of intake manifold fouling, a problem that needs to be figured out still).
Simply switching to fuel injection is a gain in efficiency right there as the fuel vaporizes better.
I have never had an engine just quit working. Not on a car (including my first jalopy) or even a lawn mower.
