TCM IO 520 scam ?
Just remind me - How many companies have gone broke chasing the lure of JetA-1 powered piston aircraft engines?
Thread Starter
Join Date: Jul 2005
Location: Queensland
Posts: 686
Likes: 0
Received 0 Likes
on
0 Posts
Do you think there is much of a future in piston engine R&D,
I'll use the IO520 as an example.New it currently sells for near Aust $50,000 and has a TBO of 1800 hours. Increase that to 3600hours and immediately the effective cost is halved. Is this possible? In the fifties and early sixties it was done with the most complex reciprocating engine ever built - the turbo compound R3350. This engine had 6 times the capacity of a 520 but put out 12 times the horse power. In cruise it achieved a specific fuel consumption of 0.4 or better .
They achieved the long life and low fuel consumption by running LOP.
All Continental has to do is sort out it's intake system and then bite the bullet and subcontract the injectors to GAMI.They should then do a deal with suppliers of engine management systems and mandate their installation. Finally they should educate their customers how to run the engine LOP.
I said more than half. The rest is fuel saving over the life of the engine With mine I save 5 litres per hour running LOP . At $2.2 per litre over 3,600 hours the saving would be $39,600 . Worth doing I think.
Join Date: Apr 2008
Location: Australia
Posts: 490
Likes: 0
Received 0 Likes
on
0 Posts
There is nothing, and I mean NOTHING that has come out of the auto industry that can compete with the TCM or Lycoming engines at the power settings we consider "normal." According to one engine test engineer in Detroit, if the best engine test facilities in Detroit run their best auto engine at 75-80% power, they can only get about 300 hours out of them. If it were easy, everyone would finish the 24 hours of LeMans. Not all even make it 24 hours at the same powers we ask of our aircraft engines every flight.
Maybe power/capacity is not a fair comparison - but it's better than a percentage of an arbitrary number that was set in part based on the reliability required.
To be frank, auto manufacturers can't afford to make engines as fragile and finicky as aircraft engines or their reputation would be junk. I have no doubt that if you had a projected market of a few million engines, auto engine designers could easily design and build an engine that was smaller, lighter, cheaper, more powerful and more reliable than current aircraft engines.
The problem is then the aircraft manufacturers would say "What we really need is something about the same size and the same weight as the current engines. And not too much more power either..." (or you run into potential problems with VNE etc) So you need to design new aircraft too. Unfortunately, the market doesn't exist to support it.
Thread Starter
Join Date: Jul 2005
Location: Queensland
Posts: 686
Likes: 0
Received 0 Likes
on
0 Posts
Andy
If this is true why has every attempt to use Auto engines in aircraft ended either in abject failure or major disappointment in the sustainable power reliably produced?
To be frank, auto manufacturers can't afford to make engines as fragile and finicky as aircraft engines or their reputation would be junk
Join Date: Apr 2008
Location: Australia
Posts: 490
Likes: 0
Received 0 Likes
on
0 Posts
If this is true why has every attempt to use Auto engines in aircraft ended either in abject failure or major disappointment in the sustainable power reliably produced?
- A custom cooling system, to provide enough cooling without excess drag
- A system to turn the propeller at an appropriate speed, without transmitting vibrations to the engine that it is not designed to handle
- Perhaps, you put a different ignition system on to give you redundancy
- Perhaps, the oil system (sump) is not designed to work in the range of attitudes encountered in an aircraft.
- You probably have to fit all this in a space designed for some other type of engine
None of these systems are likely to have the detailed engineering work done that was done on the original engine installation, and they are the typical areas where problems are encountered. It's no different to dropping a Lycoming in a car and discovering you have cooling problems, and have to strip the engine after a sudden stoppage when your foot slipped off the clutch.
I'm not arguing for auto engines in aircraft. Creating a reliable installation is a major undertaking. It's much easier to choose an engine that was designed for the task, where it is well known what is required for a reliable installation. But I don't agree that aircraft engines are superior technology to auto engines.
Some of the things encountered in aircraft engines that would not be acceptable in a car engine:
- manual mixture control. My car engine automatically runs lean cruise (lean of peak) when power settings allow.
- worries about shock cooling
- having to strip an engine or check the crank after any sudden stoppage.
- a manual primer pump, or the incantations required to start a hot fuel injected engine. Chokes on cars disappeared decades ago, if you told people a fuel injected engine could be harder to start than a carby engine they would think you are mad.
- new engines making metal with the frequency that seems to happen with aircraft engines
- worries about corrosion in engines that sit unused for a while
- changing a cylinder etc. way before the projected engine life.
Thread Starter
Join Date: Jul 2005
Location: Queensland
Posts: 686
Likes: 0
Received 0 Likes
on
0 Posts
Andy, An earlier post stated that aircraft engines need to be powerful, efficient and lightweight. I think reliability and (within reason) simplicity should be added to that list. Every new system introduced adds to original cost plus ongoing maintenance costs. Every additional system is another potential point of failure. If it aint on there it can't fail.
One old engineer reckoned water cooling an aircraft engine made as much sense as air cooling a submarine.
Another factor often overlooked is total installed weight. It's all very well producing 4HP per cubic inch or whatever but it's not much use if you then need huge radiators,huge oil coolers and a strong heavy gearbox specially made with appropriate torsion dampeners to make it all work.
All the above doesn't mean that there isn't room for improvement. One of the most promising is the PRISM system being developed by GAMI. If you're not familiar with it Google it up. Many of the problems with air cooled cylinders should disappear once a PRISM system is installed.
One old engineer reckoned water cooling an aircraft engine made as much sense as air cooling a submarine.
Another factor often overlooked is total installed weight. It's all very well producing 4HP per cubic inch or whatever but it's not much use if you then need huge radiators,huge oil coolers and a strong heavy gearbox specially made with appropriate torsion dampeners to make it all work.
All the above doesn't mean that there isn't room for improvement. One of the most promising is the PRISM system being developed by GAMI. If you're not familiar with it Google it up. Many of the problems with air cooled cylinders should disappear once a PRISM system is installed.
Join Date: Feb 2006
Location: AMONGST BRIGALOW SUCKERS
Posts: 330
Likes: 0
Received 2 Likes
on
2 Posts
It's typically not problems with the engine itself,
but with changes or systems that have to be designed to install it in an aircraft:
- A custom cooling system, to provide enough cooling without excess drag
- A system to turn the propeller at an appropriate speed, without transmitting vibrations to the engine that it is not designed to handle
- A custom cooling system, to provide enough cooling without excess drag
- A system to turn the propeller at an appropriate speed, without transmitting vibrations to the engine that it is not designed to handle
-
Perhaps, you put a different ignition system on to give you redundancy
- Perhaps, the oil system (sump) is not designed to work in the range of attitudes encountered in an aircraft.
- You probably have to fit all this in a space designed for some other type of engine
- Perhaps, the oil system (sump) is not designed to work in the range of attitudes encountered in an aircraft.
- You probably have to fit all this in a space designed for some other type of engine
I don't agree that aircraft engines are superior technology to auto engines.
Some of Andrews points questioned
Some of the things encountered in aircraft engines that would not be acceptable in a car engine:
- manual mixture control. My car engine automatically runs lean cruise (lean of peak) when power settings allow.
Does it? How do you know? When did you last take your car to 10,000 feet or even go through a wide change in atmospheric pressure? You may want the mixture dumbed down, I don't.
- worries about shock cooling
I don't worry too much about this, Jabba will pipe up shortly, shock cooling is mostly an old wives tale, not an issue.
- having to strip an engine or check the crank after any sudden stoppage.
This is safety issue, not an engine issue! and how often does your car engine suddenly and instantaneously stop while developing 75% or more power? Having kicked around the industry for a while, I have seen engines suffer a prop and go straight back into service numerous times. Most engineers will tell you that a prop strike at low power settings is highly unlikely to cause damage.
- a manual primer pump, or the incantations required to start a hot fuel injected engine. Chokes on cars disappeared decades ago, if you told people a fuel injected engine could be harder to start than a carby engine they would think you are mad.
Hard to start engines can be a problem for some pilots, I have always been able to get them started without major problems. Cars aren't impervious from this problem either.
- new engines making metal with the frequency that seems to happen with aircraft engines
How many car filters have you cut open?
- worries about corrosion in engines that sit unused for a while
Made of metal? It will corrode. This problem is in all engines.
- changing a cylinder etc. way before the projected engine life.
Not all that common when the cylinders are correctly prepared before service
Andrew, old technology does not mean bad technology. Current piston aero engines are outstanding devices. If it aint broke there is no need to fix it!
- manual mixture control. My car engine automatically runs lean cruise (lean of peak) when power settings allow.
Does it? How do you know? When did you last take your car to 10,000 feet or even go through a wide change in atmospheric pressure? You may want the mixture dumbed down, I don't.
- worries about shock cooling
I don't worry too much about this, Jabba will pipe up shortly, shock cooling is mostly an old wives tale, not an issue.
- having to strip an engine or check the crank after any sudden stoppage.
This is safety issue, not an engine issue! and how often does your car engine suddenly and instantaneously stop while developing 75% or more power? Having kicked around the industry for a while, I have seen engines suffer a prop and go straight back into service numerous times. Most engineers will tell you that a prop strike at low power settings is highly unlikely to cause damage.
- a manual primer pump, or the incantations required to start a hot fuel injected engine. Chokes on cars disappeared decades ago, if you told people a fuel injected engine could be harder to start than a carby engine they would think you are mad.
Hard to start engines can be a problem for some pilots, I have always been able to get them started without major problems. Cars aren't impervious from this problem either.
- new engines making metal with the frequency that seems to happen with aircraft engines
How many car filters have you cut open?
- worries about corrosion in engines that sit unused for a while
Made of metal? It will corrode. This problem is in all engines.
- changing a cylinder etc. way before the projected engine life.
Not all that common when the cylinders are correctly prepared before service
Andrew, old technology does not mean bad technology. Current piston aero engines are outstanding devices. If it aint broke there is no need to fix it!
Join Date: Apr 2008
Location: Australia
Posts: 490
Likes: 0
Received 0 Likes
on
0 Posts
This new type auto based engine must operate at 85-100% of it's maximum rated power for it's entire life cycle at a very high RPM, which causes accelerated engine wear.
Join Date: Feb 2006
Location: AMONGST BRIGALOW SUCKERS
Posts: 330
Likes: 0
Received 2 Likes
on
2 Posts
As I said in post #23, rated power is an arbitrary number, based in large part on how long you need the engine to last at that power. Yes, you might have problems if you use the quoted power in an auto application as the rated power for an aircraft application - but again, that might be 4 times the power/capacity you get from a Lycoming. If you were developing an aircraft engine you would be more conservative in setting the power rating.
By your post quoted above, I think that you mean that an automotive engine capable of producing 500HP can be derated to reliably produce 300hp continuously?
For an example, I have just taken delivery of a new Mercedes Benz A45 AMG. Mercedes claim the engine in this vehicle to be the most powerful production 4 cylinder engine ever made. It produces 385hp from it's 2 litres with a large turobcharger producing 26psi of boost. It will propel the car to 100km/h in 4.6 sec and claimed fuel economy is 6.9l/100km. It is actually capable of producing 300hp at 2500rpm. So we can potentially use this engine without a gearbox.
It weighs 150kg dry compared to 218kg for your average IO550. With a cooling system and other necessary equipment, it could potentialy weigh less than the Continental. Would this Benz engine last 2000 hours? What fuel flow would you get? Would you be able to keep this engine cool at altitude? I'd rather you be the test pilot.
Last edited by BEACH KING; 6th Dec 2013 at 00:38.
Join Date: Apr 2008
Location: Australia
Posts: 490
Likes: 0
Received 0 Likes
on
0 Posts
I'm not arguing for auto conversions. My original statement was:
But, you would likely end up with a different form factor and weight, which would require airframe changes. And that size market doesn't exist, so it is unlikely to happen.
Incidentally, I suspect that if you did design such an engine, it would have liquid cooling and a gearbox. The advantages from smaller components (which are inherently stronger and lighter) and not having to have finned cylinders and head assemblies to allow a few hundred hp worth of cooling from passing air would offset the cooling and gearbox weight.
I'm sure reliable light weight PSRUs could be designed. With enough money, computer analysis, testing and engineering expertise (not to mention existing successful and less successful examples) it could be done. Would it be easier or harder than designing an automatic car gearbox? I don't know, but I suspect many of the problems would be similar.
if you had a projected market of a few million engines, auto engine designers could easily design and build an engine that was smaller, lighter, cheaper, more powerful and more reliable than current aircraft engines.
Incidentally, I suspect that if you did design such an engine, it would have liquid cooling and a gearbox. The advantages from smaller components (which are inherently stronger and lighter) and not having to have finned cylinders and head assemblies to allow a few hundred hp worth of cooling from passing air would offset the cooling and gearbox weight.
I'm sure reliable light weight PSRUs could be designed. With enough money, computer analysis, testing and engineering expertise (not to mention existing successful and less successful examples) it could be done. Would it be easier or harder than designing an automatic car gearbox? I don't know, but I suspect many of the problems would be similar.
It will propel the car to 100km/h in 4.6 sec and claimed fuel economy is 6.9l/100km.
Next time you blokes see an aero engine, look very closely, for its capacity it is very small and quite light. Its fuel burn when expressed in fuel per HP is right up there with a modern auto engine and it is reliable and proven.
Just because the design is old doesn't mean it is not good. Many have tried to improve it over the years, no one has succeeded. Anyone remember Orenda? or Porsch?
Just because the design is old doesn't mean it is not good. Many have tried to improve it over the years, no one has succeeded. Anyone remember Orenda? or Porsch?
Join Date: May 2013
Location: have I forgotten or am I lost?
Age: 71
Posts: 1,126
Likes: 0
Received 0 Likes
on
0 Posts
my previous neighbour had a race car that did the same speed as my aircraft's cruise speed.
I asked him how much fuel he used. 200 litres for 8 laps of wanneroo.
to do 222km I use about 21.2 litres.
</sarcasm on> aircraft are dreadful arent they </sarcasm off>
I asked him how much fuel he used. 200 litres for 8 laps of wanneroo.
to do 222km I use about 21.2 litres.
</sarcasm on> aircraft are dreadful arent they </sarcasm off>
Yep that too! Thanks Jabba, correct terminology helps ...
