Another Cessna Diesel Discontinued
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Another Cessna Diesel Discontinued
https://www.aopa.org/news-and-media/...o-skyhawk-jt-a
I'm struggling to figure out why Aerodiesels are still struggling to gain traction. Having flown in both a Piper and Cessna diesels, they are superior to Avgas engines in every way, other than cost. However a price difference of 75c a lite is getting a little ridiculous. $2.25 for Avgas v $1.70 for jet A. Jet A is also much cheaper still that Avgas in the USA. Engines burning half the amount of fuel that's significantly cheaper than Avgas should be a no brainer.
Yes, the vibration damper has had issues but it seems to be fixed now, the engines themselves seem to be bulletproof. Is it a case of, we have always used avgas so that's how things should be. A classic paradigm. For the life of me I can't see why any company would want to operate infrastructure for Avgas, produce Avgas, when there is so little return. The entire industry needs to rationalise to a single fuel to survive. That fuel is Jet A and it is readily available.
I'm struggling to figure out why Aerodiesels are still struggling to gain traction. Having flown in both a Piper and Cessna diesels, they are superior to Avgas engines in every way, other than cost. However a price difference of 75c a lite is getting a little ridiculous. $2.25 for Avgas v $1.70 for jet A. Jet A is also much cheaper still that Avgas in the USA. Engines burning half the amount of fuel that's significantly cheaper than Avgas should be a no brainer.
Yes, the vibration damper has had issues but it seems to be fixed now, the engines themselves seem to be bulletproof. Is it a case of, we have always used avgas so that's how things should be. A classic paradigm. For the life of me I can't see why any company would want to operate infrastructure for Avgas, produce Avgas, when there is so little return. The entire industry needs to rationalise to a single fuel to survive. That fuel is Jet A and it is readily available.
https://www.google.com.au/amp/www.au...ngine.html/amp
Probably for the same reasons as above, whilst not directly stated in this article, the Americans are not a fan of diesels and never really have been. The Ford Ranger diesel is an awesome engine with limited issues, selling like hot cakes world-wide, matched to an F150 gearbox, but yet it won't even be offered there, in favour of a 2 litre turbo petro model, what the? Whatever the reason everyone buys 6 litre petrol powered V8 utes is likely the reason.
Also, the Volkswagon Diesel engine scandal hit the US very hard and they are very scared of buying diesels. They are worried about destroying the planet with emissions, so they don't buy diesels, they banned Kinder Surprise eggs for kids because they could choke on the small toys inside, but yet you can still buy an AK47. Go figure!
Probably for the same reasons as above, whilst not directly stated in this article, the Americans are not a fan of diesels and never really have been. The Ford Ranger diesel is an awesome engine with limited issues, selling like hot cakes world-wide, matched to an F150 gearbox, but yet it won't even be offered there, in favour of a 2 litre turbo petro model, what the? Whatever the reason everyone buys 6 litre petrol powered V8 utes is likely the reason.
Also, the Volkswagon Diesel engine scandal hit the US very hard and they are very scared of buying diesels. They are worried about destroying the planet with emissions, so they don't buy diesels, they banned Kinder Surprise eggs for kids because they could choke on the small toys inside, but yet you can still buy an AK47. Go figure!
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I want a diesel that behaves exactly like an IO-320. Same(ish) weight, size, power, etc. Mixture, pitch, throttle manually controlled, for the same reason I prefer a manual gearbox in the car, and non-turbocharged because I don't want the maintenance headaches. And a semi-affordable replacement for the IO-320 so I can buy an older plane and replace the engine; I'm not going to pay for a whole new plane.
If companies are unwilling to provide such an engine, then my path forward is simple: stick with avgas.
If companies are unwilling to provide such an engine, then my path forward is simple: stick with avgas.
The technology required to make modern diesels economical is two or three orders of complexity higher than current dinosaur avgas engines. Common rail fuel systems and concomitant myriad ECUs are all serious failure modes for even minor issues. If only we could make a cheap to run, light weight diesel with the technology level of GM 2 stroke.
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There are a few killers...
Parts Availability - The downtime caused by no parts in compay is not good if your relying on that machine for your income
Price - Sure, you can buy one but the cost of even converting a machine is the high initial cost.
Training - Since the 172 is most common use is training, sure, you can learn in a single lever aircraft, but whats the point? When you go for a job on anything larger guess what, you need to know your engine management and how to handle a constant speed prop and mixture control. Until there are affordable conversions for your light twins that are used in charter (and that are at a suitable weight that they are not going to use what little useful load is available), time in the 172 isn't really going to help.
STC's for other aircraft - Cost of fitting them an aircraft is high enough, yet alone having to develop an STC to fit it, change the engine instruments, engine mount, possibly cowls, and whatever else is needed...
There is a diesel 182 parked opposite our workshop belonging to somebody else, its been sitting three or more years now, no work for it, nobody interested in buying it, so it sits there...
Parts Availability - The downtime caused by no parts in compay is not good if your relying on that machine for your income
Price - Sure, you can buy one but the cost of even converting a machine is the high initial cost.
Training - Since the 172 is most common use is training, sure, you can learn in a single lever aircraft, but whats the point? When you go for a job on anything larger guess what, you need to know your engine management and how to handle a constant speed prop and mixture control. Until there are affordable conversions for your light twins that are used in charter (and that are at a suitable weight that they are not going to use what little useful load is available), time in the 172 isn't really going to help.
STC's for other aircraft - Cost of fitting them an aircraft is high enough, yet alone having to develop an STC to fit it, change the engine instruments, engine mount, possibly cowls, and whatever else is needed...
There is a diesel 182 parked opposite our workshop belonging to somebody else, its been sitting three or more years now, no work for it, nobody interested in buying it, so it sits there...
There is a diesel 182 parked opposite our workshop belonging to somebody else, its been sitting three or more years now, no work for it, nobody interested in buying it, so it sits there...
It would be the fault of the owner and their expectations on hourly rate.
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The technology required to make modern diesels economical is two or three orders of complexity higher than current dinosaur avgas engines. Common rail fuel systems and concomitant myriad ECUs are all serious failure modes for even minor issues. If only we could make a cheap to run, light weight diesel with the technology level of GM 2 stroke.
Interesting comment implying the Detroit Diesel (GM 2 stroke) is low tech...
4 exhaust valves per cylinder, roller cam followers for the exhaust valves and the unit injectors, supercharged and on some models turbocharged with inter and after coolers. Very reliable generally.
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The modern common rail diesel injection engine is not as reliable as suggested here. They are highly stressed engines, operating at incredibly high fuel pressures to maximise fuel efficiency, and minimise emissions.
The common rail injectors are susceptible to contamination, and injectors are expensive, damaged by even small amounts of water found in fuel. Anyone who has paid a dealer $5,000 to just replace common rail injectors knows this.
Older, non common rail, diesel automotive engines are less stressed, and more reliable, however don’t meet modern emissions targets.
Nissan has just announced it will no longer build diesels, and the Volkswagen debacle shows emissions are not as promised.
Consider the added complexity of a pressurised water cooling system, where applicable, in an aircraft that flies above sea level, a coolant leak is catastrophic.
Common rail desel engines would have replaced avgas already, if they were as reliable is the humble IO 320.
The common rail injectors are susceptible to contamination, and injectors are expensive, damaged by even small amounts of water found in fuel. Anyone who has paid a dealer $5,000 to just replace common rail injectors knows this.
Older, non common rail, diesel automotive engines are less stressed, and more reliable, however don’t meet modern emissions targets.
Nissan has just announced it will no longer build diesels, and the Volkswagen debacle shows emissions are not as promised.
Consider the added complexity of a pressurised water cooling system, where applicable, in an aircraft that flies above sea level, a coolant leak is catastrophic.
Common rail desel engines would have replaced avgas already, if they were as reliable is the humble IO 320.
Diesels are dinosaurs. Diesels became popular in cars in Europe because of incentives / subsidies. They were regarded as less polluting only because they used to score well on the emissions tests designed for petrol vehicles. As emissions standards have been adopted for diesel engines we see makers going to extreme measures like particulate filters and fuel additives (AdBlue) to meet the standards.
We are entering an age with direct injection / compression ignition petrol engines where fuel economy / efficiency will increase dramatically. Maybe double from current levels.
Aircraft engines have exceptional specific torque (ie torque for engine capacity) and exceptional reliability. Most car engines spend their life (say 250,000km @ 50 km/h average = 5,000 hours) typically at 15-20% of its rated power. Aircraft engines spend their life (maybe 2,200 hours) at 75% power. Try running a car engine at 75% power continuously and see how it goes.
Aircraft engine development is hampered by government regulation / certification. If we relaxed this I think we'd see a dramatic improvement. Government restrictions are the only reason we don't have cheap fuel injection / electronic ignition systems that can be retrofitted. Fuel injection and a revised fuel system that allows GA aircraft (under say 10,000ft) to run on Mogas and the aircraft world would change.
Multipoint, closed loop electronic injection with knock sensors and lambda sensors, conversion to dual alternators / dual batteries with a modern EFI fuel pump ought to be possible for around AUD$5k installed. This ought to then handle 98 Octane Mogas up to at least 10,000ft.
Look at the time it is taking the US to test the leaded AVGAS replacement candidates. And the FAA is the speed of greased lightning compared with CASA. We need to stop regulators blocking innovation.
We are entering an age with direct injection / compression ignition petrol engines where fuel economy / efficiency will increase dramatically. Maybe double from current levels.
Aircraft engines have exceptional specific torque (ie torque for engine capacity) and exceptional reliability. Most car engines spend their life (say 250,000km @ 50 km/h average = 5,000 hours) typically at 15-20% of its rated power. Aircraft engines spend their life (maybe 2,200 hours) at 75% power. Try running a car engine at 75% power continuously and see how it goes.
Aircraft engine development is hampered by government regulation / certification. If we relaxed this I think we'd see a dramatic improvement. Government restrictions are the only reason we don't have cheap fuel injection / electronic ignition systems that can be retrofitted. Fuel injection and a revised fuel system that allows GA aircraft (under say 10,000ft) to run on Mogas and the aircraft world would change.
Multipoint, closed loop electronic injection with knock sensors and lambda sensors, conversion to dual alternators / dual batteries with a modern EFI fuel pump ought to be possible for around AUD$5k installed. This ought to then handle 98 Octane Mogas up to at least 10,000ft.
Look at the time it is taking the US to test the leaded AVGAS replacement candidates. And the FAA is the speed of greased lightning compared with CASA. We need to stop regulators blocking innovation.
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The main reason our aircraft avgas piston engines have not developed into a modern, computer managed, direct fuel injection system, is the lawyers destroyed the U.S. light aircraft industry in the 1970’s.
Frivolous litigation, by the ambulance chasing lawyers, sent the manufacturers into bankruptcy, where at one point liability insurance was 50% of aircraft manufacturing cost. The lawyers saw aviation as a cash cow, and single handedly kept development in the dark ages. The motor car industry had deeper pockets,
Even Porsche, with all it’s technical support, was unable to make its aircraft engine successful, in the 1990’s.
Frivolous litigation, by the ambulance chasing lawyers, sent the manufacturers into bankruptcy, where at one point liability insurance was 50% of aircraft manufacturing cost. The lawyers saw aviation as a cash cow, and single handedly kept development in the dark ages. The motor car industry had deeper pockets,
Even Porsche, with all it’s technical support, was unable to make its aircraft engine successful, in the 1990’s.
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I've seen plenty of people decide to lease/rent an aircraft because its $20/Hour less, but then complain that it needs a paint job, or new avionics but don't want to cover the cost of them..
Or people decide to buy an aircraft "because they got it cheap" but didn't factor the cost of the engine that needs replacing in a few hundred hours, then they send it to a local shop (against advice) and winge and complain when it cost an extra $10000 more than the initial quote because of the extra parts that were needed... (which the factory just wears when you get a factory motor).
Not being nasty, but most owners just want to take the cheap way out, and at the moment avgas powered 172/182's are just cheaper than the diesels for the average private buyer.
And from an operators point of view, there are not enough advantages to make us spend that sort of money for converting an aircraft that won't lift as much as a stock aircraft.
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I can't help but feel that the diesel/Jet-A1 piston aero-engine is going to be a short-lived beast. More likely in the very light range it'll be overtaken by pure-electric aircraft (as we have already seen discussed on this forum) and in the larger (longer-range) arena someone will come up with a neat electric-turbine hybrid. Little turbines like the Solar T-62T-32 are already being used in a bunch of small helicopters (as well as in larger aircraft as an APU), they're relatively affordable, and with an electric drivetrain you can handle short-term loads and speed changes without upsetting the turbine.
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Some of you seem to be technical ludites. To the person who said "diesels were dinosaurs" I'll take you for a ride in my Audi SQ7, thense my GMC3500 L5P, we'll tow an 8,000kg trailer just for fun. If that is a a "Dinosaur" well then yes please, more Dinosaur. Millions of diesel trucks, buses and cars are produced every year, they travel billions of miles every year on the highways around the world. One of my friends bought a Semi, grossed 70+ tons for 800,000 km before any injectors needed looking at.
What will we do when the EPA revokes the dispensation certificate for tetra ethyl -lead, Swift fuel or Gammi fuel can't ramp up production to supply the world. Most of the importers of Avgas want to get out of the business, lots of $ for separate infrastructure for Avgas to sell a dribble of fuel now and then. In the near future, any sort of Avgas will be $8 a litre. It's that price now in Europe and not available in Africa at all. It's jet-A or nothing.
Piper have expanded their lineup with the Diesel Seminole. Continental have shown confidence in the sector by creating the CD-170 diesel rated at 180 hp.
What anyone believes, diesel engines burning Jet-A is the only salvation for traditional GA. The other option is to let normal GA die out and Rotax to be the default and only engine up to 130 hp. Maybe a 6 cylinder Rotax could be made for 160 Hp. Who knows.
They only sell about 2+ million of these HD diesels a year between Ford, GM, Ram and now Nissan. So you are right, Americans don't like Diesels........hint>sarcasm,
The future of GA. Trust me, I am always correct in my predictions out to 30 years.
What will we do when the EPA revokes the dispensation certificate for tetra ethyl -lead, Swift fuel or Gammi fuel can't ramp up production to supply the world. Most of the importers of Avgas want to get out of the business, lots of $ for separate infrastructure for Avgas to sell a dribble of fuel now and then. In the near future, any sort of Avgas will be $8 a litre. It's that price now in Europe and not available in Africa at all. It's jet-A or nothing.
Piper have expanded their lineup with the Diesel Seminole. Continental have shown confidence in the sector by creating the CD-170 diesel rated at 180 hp.
What anyone believes, diesel engines burning Jet-A is the only salvation for traditional GA. The other option is to let normal GA die out and Rotax to be the default and only engine up to 130 hp. Maybe a 6 cylinder Rotax could be made for 160 Hp. Who knows.
Last edited by Ozgrade3; 13th May 2018 at 09:48. Reason: Spelling
They only sell about 2+ million of these HD diesels a year between Ford, GM, Ram and now Nissan. So you are right, Americans don't like Diesels........hint>sarcasm,
I think it is pretty clear that in the not too distant future, AVGAS will be dead or prohibitively expensive for GA. The development of an unleaded replacement fuel will lead to a product that is also prohibitively expensive for GA owners & operators as the quantities of it that are made are far too small to be economically viable.
GA engine manufacturers need to stop having bright ideas on going in different directions regarding unproven 'cutting edge' technology and new fuel types and settle for something sensible and sustainable.
I think the only two options for an affordable long term solution are diesel engines that run on JET-A or conventional gasoline engines designed to run on automotive Unleaded 98.
GA engine manufacturers need to stop having bright ideas on going in different directions regarding unproven 'cutting edge' technology and new fuel types and settle for something sensible and sustainable.
I think the only two options for an affordable long term solution are diesel engines that run on JET-A or conventional gasoline engines designed to run on automotive Unleaded 98.