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A Little Eggenfellner History

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Well, it is only a couple of years ago that 10,000 faulty certified ECi cylinders had to be replaced after 800 h on certified Lycomings with 1800 h TBO. After 50 years, and they still haven't got it right :cool: It was FAA that finally issued the requirement for replacement, and the customers had to contact ECi in Texas themselves. How many experimentals are still flying with these cylinders without even knowing about it?

In contrast to Lycoming and Continental, Thielert has a constantly updated user database. For isntance in 2005, 80 clutches were replaced by Thielert, free of charge by sending out mechanics. The engine computer together with the customer database enabled Thielert to sort out other possible problematic clutches based on three incidents within hours, and contact all the customers within 48 h, all the 80 clutches were replaced within one week (If the FAA/EAA had to be involved, this would have taken months). They could do this without first investigating the cause of the error. They only knew that the three engines of concern had recently had a clutch overhaul, and so had the other 80. Later they found that the error was due to several people using wrong cleaning agent when overhauling the clutch, leading to a chemical reaction of the surface which changed the friction number. This is the same support principle as RR, GE and PW uses together with most car manufacturers. Why aren't Lycoming using it? Why do Lycomings, a 50 year old design, cost so much as they do when they are not offering something even close to this level of support?

Things happens to everyone, but to achieve 3000 h TBO can only be done in full openess and close cooperation with the customers. Thielert is doing this, Lycoming is not.

I cannot say anything about the gearbox of the Thielert, but it looks like the whole package originally is designed with very small margins to get the weight down. The engine itself (the 1.7 L) comes from a MB A-type that in the car only produces 90 HP max. In the airplane it produces 135 hp continous. The 2.0 is probably much better (or easier to get right) and it also has a lighter gearbox. A clutch is probably needed. This is a diesel with a tremendous torque (very high power peeks) at low RPM. It probably has 200 Nm already from 1200-1300 RPM, or maybe the FADEC limits this?

There are some other diesel conversions in the 100 HP range meant for the uncertified market. eco-motors. 1.4 L TDI engine (PSA? VW?) with 80/100 HP to be used as a replacement for Rotax. Compared with Rotax it weigh 24 kg more or approx 30% more. eco-fly (why this eco-xxxx ? ). This is a converted smart engine, also as a replacement for Rotax, but it doesn't look like much is happening there.

Then there is the Raptor. A turbodiesel made from the ground up to be an aircraft engine, but have not been flown. They claim 105 hp at 81 kg at 2800 engine RPM. At 2800 RPM, only 1.55 L and no intercooler, this is hard to believe, but who knows.

I would place the Egg well below the eco-motor regarding technical complexity, more in the class of the hundreds of BMW conversions flying. When Jan makes a conversion with the new diesel Subaru incl a gearbox that can manage the diesel pulses, and within weight limitations making it flyable, at the right price (preferably way more economically than a gasoline engine), then we can start comparing the Egg and the Thielert. With the same logic, the Egg (existing gasoline conversion) is probably at least just as good as the Thielert is today :)
 
Thielert's level of support does not get rave reviews in either the TAC story nor by operators or Diamond dealers. Tardy response, long wait for parts and even arrogant attitudes have been mentioned. My understanding is that Diamond is often handling the problems with the customers directly.

You'd never want any sort of clutch to be used near the max torque output of an engine to couple to the gearbox. This is a sure invitation to speedy failure, especially using a limited travel loading device for the disc.

Thielert is examining plenty of fragged parts coming back to them so they should be able to assess failure modes and design fixes.

In the case of the clutch problem here- yes the problem was detected by auto switching of the FADECs with a crank sensor code. Removal of the sensors revealed metallic parts and rust dust. Diamond authorized the removal of the PSRU to have a deeper look. Good thing the FADECs have decent diagnostics- this saved a thrust loss a few hours down the road.

Contrary to popular belief, diesel engines do not produce staggering torque levels because they are diesels, they do it because they are heavily boosted. Take away the turbo and this engine would be lucky to make 110 ft./lbs.
 
rv6ejguy said:
Contrary to popular belief, diesel engines do not produce staggering torque levels because they are diesels, they do it because they are heavily boosted. Take away the turbo and this engine would be lucky to make 110 ft./lbs.
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A diesel without a turbo is like an airplane without wings :) A gasoline engine only increases power when turbocharged (with intercooler preferably), a diesel increases both power and efficiency. Still, on low RPM (idle), the turbo is not producing any boost, but the torque is much higher than a gasoline engine due to the 18:1 compression ratio instead of 9:1. Anyone with manual transmission and a diesel engine driving at rush hour for work can subscribe to that. No need to use the gas pedal, only clutch and brake. Without a turbo, the torque usually peaks at 1500-2000 RPM and decreases sharply after that. With a turbo, the torque on modern diesels also peaks at 1500-2000 RPM (although at a much higher value than without a turbo), but stay there untill 3-4000 RPM or even higher.

The original engine used in the Thielert now (2.0L Mercedes for the A-class, the A200) has 140 hp at 4200 RPM. Max torque is 300 Nm, and this is constant from 1600-3000 RPM. The gasoline powered version (2.0 L) also has 140 hp at 5750 RPM, but a max torque of only 185 Nm at 3500 to 4000 RPM. The turbocharged 2.0 L gasoline engine has 190 hp at 5000 RPM, but "only" 280 Nm torque at 1800 to 4850 RPM. The engine controller of the Thielert is probably nothing like the original from MB, but this gives a rough picture to compare a turbo-diesel with a normal gasoline engine of same displacement.
 
Think about it gentlemen. Mean torque means almost nothing in the context of this clutch and clutch's purpose in the system.
 
DanH said:
Think about it gentlemen. Mean torque means almost nothing in the context of this clutch and clutch's purpose in the system.
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That was what I was thinking about. You explained earlier about angular vibrations, ressonance and power pulses at low RPM. A diesel with larger pulses must be harder for the gear than a gasoline engine. How much, I am not sure, but certainly larger.
 
Thread drift?

Hi Guys,
Don't you think we might start a Thielert thread? I love the idea of a good diesel, and I think that Thielert has the engineering horse power to make the engine function properly. It does seem that aircraft diesels are an idea whose time has come for GA. The original thread though was about the history of David and his approval of the Eggenfellner Subaru. There are several aircraft diesels that are worth discussing on their own merits. Lets start one.
Bill Jepson
 
Rotary10-RV said:
Hi Guys,
Don't you think we might start a Thielert thread? I love the idea of a good diesel, and I think that Thielert has the engineering horse power to make the engine function properly. It does seem that aircraft diesels are an idea whose time has come for GA. The original thread though was about the history of David and his approval of the Eggenfellner Subaru. There are several aircraft diesels that are worth discussing on their own merits. Lets start one.
Bill Jepson
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Good idea :) The more I think about it, the larger my headache becomes when fuel cost will be reduced by 50-70 % by going diesel. Here in Europe, we are almost to the point where a similar hp turbine burning Jet fuel would be cheaper to run than a O-360 burning AVGAS (if we have not crossed that point already).
 
Being an EAA'er for a long time, and an A&P even longer I can see the benefit to pushing the envelope. Nothing good comes from staying inside the box. We would still be riding horses to work (and might be again soon!) if nobody tried something new. That being said, there should be in bold letters a warning to any that want to buy these engines. They are not for the inexperienced and faint hearted. I really would not care if every jet jock and throttle actuator from here to wherever bought an experimental engine. It is just that, experimental. Taking something designed for 2 dimensional road use and putting it in the air with positive and negative g's, different cooling airflow than planned, and different hot spots for accessories are just a few of the major issues I see. And, I don't see where using fighter pilots and airline pilots as standout early adopters really helps the case of safety. Unless they are engineers and can design their own test program and know what they don't know and how to find an answer it won't help.
 
Taking something designed for 2 dimensional road use and putting it in the air with positive and negative g's, different cooling airflow than planned,
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Very true but your statement does not at all account for the 16 years I have been flying nothing but Subaru Aircraft engines.

Jan Eggenfellner
 
Jan,

I did not say it should be outlawed. Just that there are still big "what ifs" to find. That was also true of early aircraft engines of all types. There is a lot left to learn on adapting these kinds of power plants to aircraft. As long as those that use them understand that every hour they fly is a flight test, more power to 'em. For those that think you can hook up, mount up, and blast off IFR over bad terrain and all kinds of weather I would say, good luck, be careful. Sixteen years is a start...:D

Very true but your statement does not at all account for the 16 years I have been flying nothing but Subaru Aircraft engines
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Sixteen years is good. When there are 100,000 subies flying and they are hitting TBO with failure to success records as good as the legacy engines, that will be cool.
 
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CraigC said:
Jan,

I did not say it should be outlawed. Just that there are still big "what ifs" to find. That was also true of early aircraft engines of all types. There is a lot left to learn on adapting these kinds of power plants to aircraft. As long as those that use them understand that every hour they fly is a flight test, more power to 'em. For those that think you can hook up, mount up, and blast off IFR over bad terrain and all kinds of weather I would say, good luck, be careful. Sixteen years is a start...:D
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Let's hope that everyone flying single engined aircraft weigh the risks of blasting off over bad terrain, IFR or at night no matter what engine is up front. Your life is riding on it and people are unfortunately killed every month, somewhere when that engine stops. We had 5 people killed just in our local area last year under just these conditions with "legacy" engine power in 2 separate incidents (catastrophic internal failures).
 
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When there are 100,000 subies flying and they are hitting TBO with failure to success records as good as the legacy engines, that will be cool.
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See, this puts you outside our customer base immediately :) These engines are not for those wishing to wait until the technology is already old. With car engines, a 2004 is already an old model. The latest now is the 2008 3.6l engine. For Eggenfellner Aircraft, it has always been about installing the latest available automotive technology engines in aircraft. If this is not interesting or safe for some, then it is not an engine for you :)

Jan
 
These engines are not for those wishing to wait until the technology is already old
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That is your thought not mine. I did not say old. My qualification is of a PROVEN design that meets or exceeds the current expectation for the standard in aircraft engines. That means MTBF that is inline with or better than what we have with current certified engines. I also would not be so fast to classify me as outside your customer base. You say that anything old is bad. Old stuff works. If it did not it would not be around. Just like having something new does not automatically make it superior to what already exists.
 
janeggenfellner said:
See, this puts you outside our customer base immediately :) These engines are not for those wishing to wait until the technology is already old. With car engines, a 2004 is already an old model. The latest now is the 2008 3.6l engine. For Eggenfellner Aircraft, it has always been about installing the latest available automotive technology engines in aircraft. If this is not interesting or safe for some, then it is not an engine for you :)


So you are saying you throw a new engine on and do very little testing. I did not think you were selling car engines, but complete aircraft engine systems. You are saying someone buys a product from you and it is immediately outdated. Smart marketing Jan. No wonder the resale on your products is so poor. How do you support a 2004 engine when you so quickly move on to new engine cores?
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rrnixonjr said:
So you are saying you throw a new engine on and do very little testing. I did not think you were selling car engines, but complete aircraft engine systems. You are saying someone buys a product from you and it is immediately outdated. Smart marketing Jan. No wonder the resale on your products is so poor. How do you support a 2004 engine when you so quickly move on to new engine cores?
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Rich, you are skirting on the edge of "vendor bashing" here-------

Maybe you can re state your concerns in a more genteel manner.
 
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In order to be vendor "bashing" wouldn't it have to be untrue?

I too wonder how a knowledge base about problems/solutions for any particular configuration would build if the configurations are constantly changing.

It appears that such a support base is something that customers provide. So, when it leaves, it is a "tested and complete firewall foreward solution". But lifecycle support seems difficult for the factory because they do not continue with the configuation for very long.

So, long term support will be via the sharing of information among customers.

Of course any change immediately renders the "solution" not an eggenfellner aircraft engine.

Am I missing something?
 
rrnixonjr said:
janeggenfellner said:
See, this puts you outside our customer base immediately :) These engines are not for those wishing to wait until the technology is already old. With car engines, a 2004 is already an old model. The latest now is the 2008 3.6l engine. For Eggenfellner Aircraft, it has always been about installing the latest available automotive technology engines in aircraft. If this is not interesting or safe for some, then it is not an engine for you :)


So you are saying you throw a new engine on and do very little testing. I did not think you were selling car engines, but complete aircraft engine systems. You are saying someone buys a product from you and it is immediately outdated. Smart marketing Jan. No wonder the resale on your products is so poor. How do you support a 2004 engine when you so quickly move on to new engine cores?
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Prior to release of this engine to the public, Fuji Heavy Industries has completed many thousands of hours of testing and validation to ensure that this engine is as good or better than the previous proven EZ30 which now has hundreds of MILLIONS of hours of service on it. This validation process dwarfs and exceeds anything Lycoming or Continental can or has ever done with any of their engine designs and would be similar in scope and cost to what GE or Pratt & Whitney does before releasing a new turbofan engine. We don't worry much about core engine reliability on automotive engines these days even if used in aviation.

The basic similarity of the EZ30 and EZ36 engines makes updating more of an evolutionary process as far as systems are concerned. I would guess that Jan will be performing considerable running on his test stand of the new engines prior to first delivery to get the details worked out.

Why this hostility from the "Old Guard" creeps in every couple of months on this topic continues to puzzle me. Please, educate yourselves a bit before sprouting off.
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rv6ejguy said:
rrnixonjr said:
Why this hostility from the "Old Guard" creeps in every couple of months on this topic continues to puzzle me. Please, educate yourselves a bit before sprouting off.
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I like Lycs, but totally agree with you! I didn't find any basis of fact, in the last few postings either. Perhaps it's because I still like my trusted Honda motorcycle engine (six cylinder/ liquid cooled)after all these years; and wouldn't have to think twice, about a "newer" model. It's just a case of knowing the company's product history over a lot of years.

L.Adamson
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I gotta agree with Jan and Ross on this one - even though I have no skin in the game at this point, I would not worry one iota about the core engine going Tango Uniform. It's the support system that is much more likely to be an issue, and that's entirely a factor of the way the individual builder put it together. The only exposure I can see from Jan's standpoint is the gearbox. The engine is doing exactly what it was designed to do - and as long as you can manage to keep it cool, fed, and lubricated, it will keep on doing it. The gearbox would be the only component I would worry about from a catastrophic mechanical failure standpoint - and from what I've seen and read, I have a fair degree of faith that due diligence has been performed for that design to reasonably assure against it. Fuel, coolant, electrical, and oil systems all will have so many individual differences between aircraft installations that the builder will have to assume responsibility for making and keeping them operating properly, with the resulting likelihood that any problem gremlins will be in those areas - not the core engine.

As Jan has said - this option is not for the "bolt it on and forget it" flyer - this is for the guy who likes to tinker and take the road less traveled.
 
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no doubt the engine is good as a car engine.

How many hours did Fuji spend testing the entire package, inclusive of the PSRU, and alternate fuel and engine management system?

I agree that this is not for the bolt on and fly crowd it is for the experimenters...with a capital "E". Sadly, that is not how it was presented.

It is frankly a non sequitar to repeat time and again that the core engine is solid. So what. It is the package. And when the combination keeps changing it makes it difficult to have much faith.

If I were trying to sell you a prop, and I told you than there were over 500 flying, you would want to know that those were all flying on O-235's before you decided to put it on a 320, 360, or 540...right?

So to say that there are hundred of 2.5's flying on gyrocopters, as a way of validating the package design for a 3.6 or 3.0 turbocharged model seems misleading.

For example the Gen 2 psru was validated by "hundreds of installations", yet when installed on the STI's it becam "marginal in every respect" according to Jan....then it became grounded for the whole fleet.

The 3.0 RV 10 or turbocharged package has never successfully flown more than a handful of hours, (by success I mean with a turbocharger that is functioning, not overheating, and not siezed) and now a bigger engine with more output is being built of the previously unvalidated package.

No doubt the 3.6 is a great car engine, no doubt the packaging requirements for that application that caused the use of a "porkchop" rod were soundly engineered. How much time do you think Fuji spent analysing the loads on those components with a prop load, and an aircraft duty cycle?

I am sure this will cause some more marketing hype...but why not just answer the questions....with factual answers and not naked claims like "we've never had a failure" or "the core is solid" or "testing is secret and if we told you how we tested we would loose our secrets".
 
airguy said:
I gotta agree with Jan and Ross on this one - even though I have no skin in the game at this point, I would not worry one iota about the core engine going Tango Uniform. It's the support system that is much more likely to be an issue, and that's entirely a factor of the way the individual builder put it together. The only exposure I can see from Jan's standpoint is the gearbox. The engine is doing exactly what it was designed to do - and as long as you can manage to keep it cool, fed, and lubricated, it will keep on doing it. The gearbox would be the only component I would worry about from a catastrophic mechanical failure standpoint - and from what I've seen and read, I have a fair degree of faith that due diligence has been performed for that design to reasonably assure against it. Fuel, coolant, electrical, and oil systems all will have so many individual differences between aircraft installations that the builder will have to assume responsibility for making and keeping them operating properly, with the resulting likelihood that any problem gremlins will be in those areas - not the core engine.

As Jan has said - this option is not for the "bolt it on and forget it" flyer - this is for the guy who likes to tinker and take the road less traveled.
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Well said. After many years of learning what to do (and not) with fuel system design, backup battery layout and switching and PSRUs through thousands of hours of air time, the latest offerings have a pretty good record as do the original EJ25 atmo conversions. It is absolutely true that total reliability is dependent on the above systems in automotive conversions. We have not seen fuel system problems for a long time, nor electrical ones (using the approved layout) and so far the PSRUs are looking good as well although more time is needed on those to draw conclusions.

If anyone can point me to an accident caused by an internal engine failure of a properly assembled and maintained Subaru, I'd be interested in the details so that we might apply the lessons.

Not to stir the pot but rather as a reality check to the "Old Guard", a quick check of the NTSB database over the last 5 years showed no less than 72 catastrophic certified engine failures in the US alone resulting in accidents. This figure does not include oil starvation following loss of oil or maintenance/ assembly/ bad mods issues (a surprisingly high number :eek:). It does not include failures where no airframe damage occurred as in ones like the Piper video incident linked on VAF a few weeks back. I can add 4 more to that count just from my data base from my local airport within that time period.

The Aviation Consumer recently noted the frequency of engine failures as an accident cause in some certified model reviews was in the 6-10% range.

I don't think we should become complacent about flight in single engined aircraft, period. Power losses do happen more frequently than many realize or choose to believe.

With regards to unapproved mods to systems that vendors have designed and tested, I can only say, do these at your own risk. Invariably the finger is pointed at the vendor after an incident despite the fact that the builder may have modified critical systems because he thought it was better. You truly are a test pilot if you do these things. This is not saying that some things cannot be improved on, just saying that careful evaluation of any mod is in order and that you are on your own. Gary Newsted's succinct reply on Jan's forum about the diode/ switch debate sums this up very well for those interested.
 
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Jconard said:
So to say that there are hundred of 2.5's flying on gyrocopters, as a way of validating the package design for a 3.6 or 3.0 turbocharged model seems misleading.

For example the Gen 2 psru was validated by "hundreds of installations", yet when installed on the STI's it becam "marginal in every respect" according to Jan....then it became grounded for the whole fleet.

The 3.0 RV 10 or turbocharged package has never successfully flown more than a handful of hours, (by success I mean with a turbocharger that is functioning, not overheating, and not siezed) and now a bigger engine with more output is being built of the previously unvalidated package.

No doubt the 3.6 is a great car engine, no doubt the packaging requirements for that application that caused the use of a "porkchop" rod were soundly engineered. How much time do you think Fuji spent analysing the loads on those components with a prop load, and an aircraft duty cycle?

I am sure this will cause some more marketing hype...but why not just answer the questions....with factual answers and not naked claims like "we've never had a failure" or "the core is solid" or "testing is secret and if we told you how we tested we would loose our secrets".
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The first point merely shows how solid the core EJ22/25 engine is, having accumulated many tens of thousands of flight hours. This obviously cannot be related to EZ series flight hours as they are totally different designs.

I would agree, the Gen 2 was not up to the torque output of the STI engines and perhaps marginal on the atmo EZ30s. Jan brought out the Gen 3 and recommended it for all the later type engines to improve flight safety. Little different from the many ADs that have been issued on certified engines over the years for the same purpose.

I do believe that the EZ30 turbo package accumulated over 100 flight hours in two different airframes. Turbos don't overheat per se unless turbine inlet temperatures exceed the manufacturer's limits. Seizures are almost always attributed to lack of oil supply to the unit or overspeed.

No prop loads are transferred to the engine, the PSRU takes all of these. We do not know about TV loads of course. Fuji performs WOT high rpm testing in excess of the requirements for certified engines. The Eggenfellner engines are operated about 1000 rpm below the factory redline at takeoff and climb power and about 2000 rpm below this in cruise. Again, we don't see any evidence to date that this is causing high wear or failures unless you have some data you'd like to share with us?

Failures during testing are a reality of the validation process for most types of engines which is the whole point of it. This should be obvious. Pratt recently suffered a low pressure turbine failure on a new turbofan design during validation http://www.aviationweek.com/aw/generic/story_channel.jsp?channel=defense&id=news/F35B02068.xml. This resulted in a design change to correct the problem. Do we condemn this model in the future because of this?

OEMs routinely do destruction testing to determine strength margins for parts. Blade off, intentional imbalances, high temperatures and high rpms are all used. Flogging a turbocharged engine past recommended limits is an excellent way to discover what is a safe operational limit for that design. I don't see a difference here. Tests are done to improve the package and establish realistic limits on MAP, rpm, oil and coolant temperatures for long life and reliability.

Even big companies like Pratt, GE, Lycoming and Continental don't get it right the first time after release of the design for production. I'd expect a little more understanding from people when new developments show some problems along the way.
 
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Excellent point Ross, on the F-135 engine. Notice P&W is going in and fixing the problem on the engine, and then continuing with the extensive test program. "Clean Sheet" redesigns every 2 to 3 years yield no product improvement, only a new subset of problems.
 
I'm sure that Fuji has had to redesign certain engine components over the years but they don't release details of what might have gone wrong during testing and validation. We rarely get insights in this these aspects.

I am also not saying that even after the design is released for production can we be assured that no problems will surface in widespread use. We see issues with most of the best auto OEMs including Toyota and certainly in aerospace like the Shuttle and in commercial gas turbine engines where failures uncover design weaknesses in service.
 
rv6ejguy said:
I'm sure that Fuji has had to redesign certain engine components over the years but they don't release details of what might have gone wrong during testing and validation. We rarely get insights in this these aspects.

I am also not saying that even after the design is released for production can we be assured that no problems will surface in widespread use. We see issues with most of the best auto OEMs including Toyota and certainly in aerospace like the Shuttle and in commercial gas turbine engines where failures uncover design weaknesses in service.
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Ross,

You know I'm not taking about Subaru or Toyota, don't you?
 
Once more into the breech.

It has always been an adage of mine to wait several years before you buy a new product to see how well it stands up to the real world. I believe this is solid advice even when buying cars from manufacturers as well regarded as Honda, Toyota, or Subaru. One nice thing about buying a car is there are many sources to evaluate the long term reliability of a product.

I am not one of the Old Guard who is hostile to new technology. In 1973 I wrote a letter to the editor of Flying Magazine asking why someone had not converted a liquid cooled automobile engine to aircraft use. It was in response to an article about issues with aircooled aircraft engines. I was fifteen years old. This is a development I have been looking forward to for many years. When I find a viable product I will be the first to switch from the old Lycoming to a new, water-cooled powerplant. Especially as the Lycoming 0-320 in my RV-4 almost seized in mid-air when a corroded lifter failed, sending pieces into the engine which destroyed my camshaft, broke a piston skirt, and put three holes in the case.

Ross, I respect you and like what I have seen of your SDS engine management system even going so far as to recommend it on the Pelican website. I think you are a great fabricator with skills far beyond the ordinary builder. It?s exciting to see your 3.3 Subaru package come together. That being said, I am not hostile, and I am educated enough to spout off on some of the problems I see with Eggenfellner?s approach. No need to get too defensive. Jan said a 2004 engine is already old. That makes absolutely no sense to me. A good design is a good design. And by the way, I have no problem with a Subaru engine, it?s the development of the total package I am concerned about and data about reliability. Where is the data? Normally, manufacturers provide it. And I don't mean Fuji Heavy Industries, they would probably run in the opposite direction.

That being said I will apologize if I was not genteel enough Mike. I did not realize that vendors were a protected species here. People generally ask tough questions about expensive products, especially when flying behind them. Like I said, I spend lot?s of time on the Pelican site and they have rules about product promotion. If I can't ask tough questions I won't consider the product.

Lastly, I live in Virginia and fly most weekends to busy airports. Nobody I know has an Eggenfellner engine in their aircraft. One guy at my airport has an NSI engine. I can?t wait to see it run. Time will tell but currently my opinion is Eggenfellner?s engine packages are not a great value for me. Hopefully time will prove me wrong.
 
The type of testing required for certified engines is very instructive on how the egg SYSTEM might be tested.

Yes I know they run the car engine on a dyno in all sorts of cyclic conditions, but....to duplicate even the certified tests you claim are no where near as difficult you would have to take the whole package and:

1. Load it up at maximum designed prop load. (with a PSRU)

2. Keep the water temp at maximum redline (260 plus) Probably should keep the PSRU at maximum design temperature...Is there such a thing, has a design limit for temp been set for the PSRU?

3. Keep the oil at maximum (300) at the inlet, after the oil cooler.

4. Run it at maximum takeoff power.

repeat as specified.

If you want to read the test protocal, it has been posted before, or you can read it on Jan's site along with the rest of Ross's epistle there. (It is his response to the questions posed here...strange that he makes his response in the only place he would answer no questions).

Wherein it is claimed that no facts back up the notion that automotive duty cycle is different than a plane.

Quick math...a car going 60 mph, in order to get 30 mpg, would be burning 2 gal per hour or 12 pounds per hour. Assuming .45 specific output, it would be 26 hp....In other words, what is so doggone obvious that it shouldn't need math now has some.

As to reliability, Ross and others constantly talk about a few big six turbo models which had problems, not the relatively bulletproof record of the O-320/360 series.

They talk about the crank AD, but when Rhonda cleared that up by describing the factory support in terms of $$, all were silent.

How about this....Doing an NTSB search on Lycoming, I could only find about 12 non fuel starvation related engine failures leading to a crash....IN ALL AMATEUR BUILT AIRCRAFT LISTING LYCOMING.

On the other hand It was very easy to quickly find more than 20 in flight total failures for subaru powered experimentals.

Since, according to Jan, the fleet has no one plane with more than 500 hours on the same installation, and there are a few hundred flying....well you get the idea.

Even on this site...

Ross...one crash thank god you survived.
Jan....three total engine failures that we know of.
Domeir...is it one or two??

Assume that there were 500 flying, with a fleet average of 300hours. That would be 150 thousand hours and assuming only 20 failures...the fleet MTBF would be 7,500 hours.

There are over 5600 rv's flying...at leat 5,000 of them with lycoming power, assuming a fleet average of 300 hours (to keep it similar), that 1.5 million hours, divided by 15 (more than I could find but makes the math simple), and you have a fleet MTBF of 100,000 hours. Remember that the numbers, which have been picked here for simplicity are much better than even these estimates.

Or again, the data to show what is pretty doggone apparent, that an awful lot of these things are making "non-optional landings" given the very small portion of the fleet they occupy.


Say "its for experimenters" all you want, that is not what is being represented. People are told that they are buying a tested, engineered, validated FWF PACKAGE....they are told that it can bolt on in an afternoon.

Sadly those claims are untrue....What is true, is that things are eyeball engineered, sold as if they are tested, and by the time flaws surface, well its on to the next generation, "that was experimental after all, you bought the bleeding edge sir...why cry when you're bleeding?"
 
rrnixonjr said:
That being said I will apologize if I was not genteel enough Mike. I did not realize that vendors were a protected species here. People generally ask tough questions about expensive products, especially when flying behind them. Like I said, I spend lot’s of time on the Pelican site and they have rules about product promotion. If I can't ask tough questions I won't consider the product.
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Rich, my issue was with how you came across when asking the questions.

Not the questions themselves.

Please take a look at this post, and also the link to "the rules" contained in this post.

http://www.vansairforce.com/community/showthread.php?t=9812

Thanks,
 
rrnixonjr said:
It has always been an adage of mine to wait several years before you buy a new product to see how well it stands up to the real world. I believe this is solid advice even when buying cars from manufacturers as well regarded as Honda, Toyota, or Subaru. One nice thing about buying a car is there are many sources to evaluate the long term reliability of a product.

Ross, I respect you and like what I have seen of your SDS engine management system even going so far as to recommend it on the Pelican website. I think you are a great fabricator with skills far beyond the ordinary builder. It’s exciting to see your 3.3 Subaru package come together. That being said, I am not hostile, and I am educated enough to spout off on some of the problems I see with Eggenfellner’s approach. No need to get too defensive. Jan said a 2004 engine is already old. That makes absolutely no sense to me. A good design is a good design. And by the way, I have no problem with a Subaru engine, it’s the development of the total package I am concerned about and data about reliability. Where is the data? Normally, manufacturers provide it. And I don't mean Fuji Heavy Industries, they would probably run in the opposite direction.

Lastly, I live in Virginia and fly most weekends to busy airports. Nobody I know has an Eggenfellner engine in their aircraft. One guy at my airport has an NSI engine. I can’t wait to see it run. Time will tell but currently my opinion is Eggenfellner’s engine packages are not a great value for me. Hopefully time will prove me wrong.
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No problem. I too would never buy the first model year from any manufacturer either due to exactly what we have been discussing here. Even the best like Toyota (I've owned about 15 of them) occasionally produce a dud. We live in the real world, not a lab.

The EZ36 will be the choice of many in the future as it has the cubes to do a better job on the bigger airframes with little weight penalty over the 3 liter. People were asking even before it was released over here. I wouldn't get upset about the "old" comment. As you well know, auto engines today don't stay the same for very long before something lighter, quieter, cleaner and more powerful comes along. Most 5 year old designs are pretty dated compared to the latest stuff.

Jan believes in flying the stuff, not publishing long reports. That works for many but not all potential clients. Other vendors have done it the other way and people ask how many hours they have on it- a fair question in my view. The others have not survived and I just got an E-mail today from another vendor's customer who had been left high and dry with zero support asking for my help to get his bird flying. I don't see much believable data from any other engine vendors at this time. NSI and CF published nonsense data which was purported to be the gospel, professionally represented and dutifully swallowed by eager customers. I'd rely a lot more on what people using a product have to say than the vendor. Jan has a lot more engines flying than all the other vendors combined. That says a lot in my book.

I wish there would be more independent tests done, especially fly offs. Marc at Kitplanes, are you out there? People are really interested in this stuff.

Finally, thanks for the kudos but I'm only a fair fab guy. My friend Jim who did the SDS 930 rocket sled install on Pelican has a lot more talent than I do. I'm a turbo/ engine guy first and a fabricator second. I just happen to like unique projects.
 
Yukon said:
Excellent point Ross, on the F-135 engine. Notice P&W is going in and fixing the problem on the engine, and then continuing with the extensive test program. "Clean Sheet" redesigns every 2 to 3 years yield no product improvement, only a new subset of problems.
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Gas turbine and auto engineers cannot sit idle for long, hence the rapid release of new designs. Mandated emission and fuel economy targets drive both of these plus competitive pressures from other marques. Lycoming and Continental don't have much pressure from either source to change. If the Feds mandated tough emission laws for piston aircraft engines, you would see a big change very quickly in hardware.

This is the impressive part of auto engine development- emissions several orders of magnitude less, power per cubic inch way up, power to weight ratios way up, NVH way down, longevity doubled perhaps, maintenance halved and fuel economy way up-all in about 20 years.

Same with gas turbines- the old designs won't pass emission and noise targets and the airlines demand lighter weights, less maintenance, lower fuel burn and longer life.

I agree that many times you create a lot of headaches with new designs but ultimately we do have progress and lots of openings for engineers.:)
 
Jconard said:
As to reliability, Ross and others constantly talk about a few big six turbo models which had problems, not the relatively bulletproof record of the O-320/360 series.
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I once naively believed that Lycomings were bulletproof. Until I had to pay thousands of dollars to fix cylinder, piston, and valves in my O320, and outside of the core engine, I also had to have alternator, carburator (twice) and exhaust work done over the course of 4 years of owning that airplane.

Based on the number of O320/360s I have seen in my local FBO for engine repair work, I am sure others can speak up as to their own personal Lycoming woes.

Lycomings may be a good engine, but bulletproof they are not...

-Dj
 
I haven't been reading for long, but enjoying it so far. I am interested in getting back into flying. Though my career involves aviation, most of my 'gear headed' recreation has come by way of automotive ventures, and probably still will indefinitely.

That said, I have recently seen potential for bringing piloting into my life with practical purposes beyond just recreation. It would appear there is good potential for doing this economically with an experimental aircraft. Strangely I just realized this renewed interest comes as I turn 34, twice age 17, when I earned my license. Maybe it's a sign.

I searched 'Eggenfelner 2.2' etc. based on on ad I recently found for a used experimental for sale. I found some good info, but much like found in the automotive ranks, I found a bunch of back and forth polarity, most of which seems to come from the 'Lyconite' crowd.

I'm not sure yet, what kind of power loss % are being quited for prop speed reduction units, but it is clear a direct drive prop should be more efficient. I understand there may be some issues with the crank hub strength in automotive engines vs. however Lycoming etc. design there cranks with direct prop loads in mind. These issues are addressed with the PSRU, at least we hope as far as long term durability are concerned?

I'm not sure how much of an issue direct drive would be for a Subaru, but it seems the new diesel versions of these flat engines might take care of the issue of putting the ideal power band in the same ballpark as a typical air-cooled aircraft engine, say 1500-2700 prop rpm. Can anyone confirm diesel flat 4s and or 6s are now in production for the European market?

The idea that a carbureted, air-cooled, low rpm, low compression Lycoming would be able to compete with a modern n/a fuel injected automotive engine seems laughable at face value. I've noted a few stating they are roughly the same, but roughly is a relative term. Can anyone post BSFC (brake specific fuel comsumption) for both types of engines? I would think the latter would be somewhere in the range of 10-20% better on fuel consumption for equal output with a prop drive eating into some of that. Throw in the less expensive fuel requirement and things seem to stay in favor of an automotive design, not considering some issues with weight and packaging for liquid cooled design.

On compression ratio, correct me if I'm wrong, but aren't air-cooled designs the same or lower than what would typically be required for automotive gasoline octane levels? Am I correct in assuming 100LL is specified as a anti-detonation safety cushion?

Back to diesels. Anyone know how much more the flat diesels weigh? I'm guessing 50-100 pounds, which is certainly significant for a light aircraft, but insurmountable? Diesels are great on fuel consumption especially in very light and heavily loaded parameters. Fuel can be saved especially on the ground taxiing and at high output climb and cruise. At moderate loads, things are still better than gasoline.

I am already psyched by some of the mile per gallon capabilities by way of GPH / IAS data I'm seeing quoted for two place aircraft at relatively high cruise speeds, how about some best economy figures at ground speeds around 100 mph? Anyone have some real world data? Anyone getting 30 mpg?
 
A Lyc will drink your milkshake

:D
FlightOps said:
Ihe 'Lyconite' crowd.
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Is that a derogatory term? :D

Welcome to the group! :D My opinion is different than yours. I'll defend the Lyc, not a put down of your opinions. Alt engine guys do compare their engines to lycomings for good reason. Irritatingly some bash with out facts. The word "modern" is my pet peeve. That's OK because the Lyc out performs other engines in the real world. The Lyc design, manufacturing, materials and technology is intentional & modern. It's still as valid today as when designed, which has been steadily & continuously improved since. The electronic part is moot. I'll explain.

The Horz opposed Lyc development, mid 50's, is based on vast knowledge gained through WWII gov research and on their radial engines. BTW P&W aircooled (1940's) radials WIN ultimate GOLD at Reno. The Lyc & Continentals win Sportsman class Reno gold. Alternative engines? The thunder mustang, scale P-51 does well. The Falcon 600ci is a very special custom deal. The T-mustang kit (out of production) w/ engine & prop = $300,000! 1/2 to 3/4 million to finish? Comparing a Subaru or Mazda engine to a Falcon engine is like comparing a Sabaru to an IRL Indy race car.

Nothing is antiquated about a Lycoming. Silicon filled exhaust valves? Since 30's or 40's, superchargers, turbos, overhead & dual overhead cams, 4 valves per cylinder, fuel injection, diesel aircraft engines......much going back to the 20's. NOTHING NEW. Lyc made a push rod engine intentionally for good reason; they did it right. Lycomings now have roller cams, composite sumps, 3 or 4 kinds of electronic ignitions.....the list goes on. Nothing OLD about it, and they're proven.

These issues are addressed with the PSRU, at least we hope as far as long term durability are concerned?
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Really? I don't put my life in the hands of HOPE and candy cane wishes. That is debatable and of great controversy today.

Can anyone confirm diesel flat 4s and or 6s are now in production for the European market?
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The new certified aircraft diesel is having lots of problems (which you can't buy direct and cost a mint if you could). Cars? yes Subaru has a flat diesel for the Euro market, fingers crossed for North America in '09; I want one (to drive). To acquire new? Expensive & unlikely at this time. They're complicated with lots of electronics. Troubleshooting a one of a kind home brew installation? 100's if not 1000's of extra hours to work the bugs out with unknown results. Install a Lyc per RV plans, go fly, almost zero troubles w/ known results. Diesel fuel econ is not better due to compromises in cooling drag and prop.

The idea that a carburetor, air-cooled, low rpm, low compression Lycoming would be able to compete with a modern n/a fuel injected automotive engine seems laughable at face value.
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I can't disagree more, no offense. "Modern" means what? The 4-cycle engine (otto) thermodynamics have changed? As a VAF poster coined, a Lycoming is not a Dinosaur but a Crocodile, totally adapted to its environment & mission.

Electronics? You make me laugh. How does that help cruising 100% at one power setting? Lycs have electronic ignition w/ MAP'ed advance curves now, good for 2%-4% nominal fuel econ gain. Dual magnetos may be OLD, but they work & are reliable, no battery needed. Top Fuel 4.5 second quarter-mile drag cars, use them! OLD? ha-ha.

Fuel injection? Lycs have fuel injection (+40 years). The difference, Lyc has a mechanical fuel pump & FI that does not need a battery to run. Many MODERN auto engine powered experimentals have fallen out of the sky due to electical issues. Lycs can run LOP with fuel injection.

10-20% better on fuel consumption?
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Lycs are VERY fuel efficient if you're a decent airman of any kind, and you can more a red knob with some skill. Lycs can run LOP.

Lycs dynoed make or exceed their rated at 180hp @ 2,700 rpm routinely. Car numbers (max HP) are at crazy near red line RPMs (say 6,000 rpm). Also car numbers are suspect to start. The "claimed HP" of alt engines RV's does not match their performance. Alt engine guys don't dare run red line RPM's all day or even take-off at red-line. A Lyc can fly 2,700 rpm all day long, no worries.

The "typical" Lyc powered RV is lighter, faster (less cooling drag), simpler, relying on less stuff (radiator, hose, electric pumps and electronic battery dependant ignitions and fuel injection). Also there's a wider and better prop selection for the Lyc, aka Hartzell BA (blended airfoil) or Sensenich fixed. Hyd c/s is superior to electric.

Modern? Good greef, who wants extra stuff that can fail? Air cooling? Let me just say in a plane there is lots of air to use. Direct AIR ENGINE FIN heat transfer is simpler, lighter than air>fin/tube>liquid>engine. A car goes 75 mph, drag is less an issue. A cars large "fuselage" cross section gives a radiator room and affects drag less. Yes P-51 (early 40's) was water cooled. The airframe was made around the engine. The RV is made for a Lyc.


On compression ratio, correct me if I'm wrong, but aren't air-cooled designs the same or lower than what would typically be required for automotive gasoline octane levels? Am I correct in assuming 100LL is specified as a anti-detonation safety cushion?
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Lycs top out at 8.5 & 8.7 to one CR. Guys run higher compression, but Lyc came up with these CR's for reliable safe ops on 100LL, which works with the future Av fuel 92UL/95UL. Lyc certified a few 9, 9.7 and 10 to one CR's. What's the point? You can't buy purple 130 octane fuel any more. How much compression do you want?

Back to diesels. Anyone know how much more the flat diesels weigh? I'm guessing 50-100 pounds, which is certainly significant for a light aircraft, but insurmountable? Diesels are great on fuel consumption.....better than gasoline.
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It'll weigh more than Richard Vangrunsven imagined hung on the nose of his RV design for sure.

Your guess is off. Short block minus heads might weigh that. Survey empty weights of flying Lyc and Alt engine RV's. I have. You'll see. ;) Alternative engine guys do not advertise their empty weights. Why? I suspect some are embarrassed about high empty wt. It makes your RV non-aerobatic worthy & reduces useful load, unless you bump gross above Vans specs arbitrarily. Than you have a dog. Alternative engines MUST use light weigh fixed wood or composite props (to protect the PSRU :rolleyes: ), so some weight is saved over a metal Hartzell or Sensenich. BTW electric MT's are expensive.


I am already psyched by some of the mile per gallon capabilities
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Sadly no. Alternative engines often burn MORE down low at the same speed. With a turbo, flown well above 10,000', Alt engines do OK and can get as good or better Lyc sfc. A turbo is more money, weight and cost. You can turbo a Lyc of course. To get turbo econ you need to fly high & suck O2 from a bottle. (Watch lower Vne)

A Lyc RV, fuel injection balanced injectors or CARB, electronic ignition at sub 75% power can well over 25 mpg. Like ALL RV designs weight is critical to overall performance. My carb'ed RV-4 Lyc could get 25 mpg at 190 mph. If I was willing to fly higher or slower I'm sure I could get close to 30mpg. I know RV-9's are doing +30 mpg with 320's at max range speed.

The fundamental laws of thermodynamics, mechanical design, otto cycle and piston/valve reciprocating engines has not changed. That is why your "Modern" engine comment is not valid & funny.

Lyc is a purpose built air-cooled direct drive low RPM, high torque engine specifically made for aircraft; a converted or adapted car engine has a challenge to match it. A Lyc is a crocodile and will eat alternative engines. :D I would not laugh at a Lycoming since it will "drink your milkshake".
 
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FlightOps said:
=I am already psyched by some of the mile per gallon capabilities by way of GPH / IAS data I'm seeing quoted for two place aircraft at relatively high cruise speeds, how about some best economy figures at ground speeds around 100 mph? Anyone have some real world data? Anyone getting 30 mpg?
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Welcome to VAF

I have never understood the need to covert to MPG in an airplane. It is a receipt for disaster. I can just see some newbie pilot saying; "I figured 28.8 MPG! Why did I run out of fuel?" MPG is based on following roads, which in and of itself is useless in an airplane. Airplanes go in a straight line to the destination over roads, stop signs, traffic, ect, and it does not account for ANY head or tail winds. When you just go flying for the fun of it and land back at your own airport how do you keep track of MPG? GPH is the only way to measure fuel burn in an aircraft. It is TIME SAVED & FLYING PLEASURE that needs to be factored into your equation not MPG.

GPH is the measure of economy in an airplane, and clearly you have come to the right place. Experimentals get much better GPH / speed ratings than certified counterparts, and specifically RV's are easier to fly, go faster, are cheaper to maintain, and hold their value better than than any other homebuilt aircraft.

Don't get hung up on economy when trying to figure out which is cheaper. I can tell you right now driving is always cheaper. You really want to save money? Walk, ride a bike, or get a horse. What you have to ask yourself is how would you rather get to your destination, and how long will it take you? I live in Lincoln, NE. I can be anywhere in the country in 6-8 hour max. Try that driving. The time, and the pure enjoyment of flying I get is worth it to me.

If you are really looking to save money you won't even consider an "alternative" engine in an aircraft. If you want to tinker or be an inventor, or be on the cutting edge of experimental aircraft engine evolution, then by all means go for it, and you can't go wrong with a Subie set up. I will help you hold the flash light.

I'm not trying to pick a fight or call you out. New blood & ideas is aways a good thing.

I really do want to welcome you to VAF.
 
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gmcjetpilot said:
Install a Lyc per RV plans, go fly, almost zero troubles w/ known results.
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I only wish this were true, but as I and others that have had troubles with their Lycoming O320/360s have already pointed out, it isn't.

Lycomings are not "bulletproof", and you will not have "almost zero troubles". If these were true I wouldn't be out a few thousand dollars in engine repairs.

Let's be realistic. Mechanical things break, and that includes both Lycomings and Subarus.

-Dj
 
Good stuff, more than I could hope for in the average ground dwelling forum.

Ok GMCJet has indicated Lycoming and the gang are keeping up with the modern era on their engine management. Keep in mind I have flown carbed rental stuff since day one. Is LOP lean or proper, aka lean of stoichiometric or what? That is a question I had. I know how to lean an engine out with the mixture control, I also know how to do it with a computer or mixture screws, jets and needles. However, I don't think I've ever known what air fuel ratio I was leaning to in an airplane. Based on the fact we wait for an rpm drop and or rough running and my knowledge of what ratios tend to do that, I'll go out on a limb and say I'm leaning it to 15-16:1 at a typical cruise setting with 2400-2500 rpm on a fixed prop. I know I've leaned fuel injected automobile engines into the 17:1 range for typical freeway speed cruising. Quite frankly I wouldn't be surprised if the Lycs were going this lean, I'm just guessing they're not given the relatively high percetage of available power they're operating at with the typical prop config.

Clearly a typical air-cooled aircraft engine with a direct drive set up to turn something on the order of 2500 rpm with peak power between there and 3000, could also be called the 'truckers dream' except for the fact it's fueld by gasoline. Low power/displacement doesn't typically lend itself to low BSFC. This rpm range is dictated by aircraft size, which effects reasonable prop size. Prop tip speed comes into play etc. None of these considerations come into play with automobile engine design.

So, air-cooled does well when it comes to output/engine weight, but it seems as though the liquid cooled flats are in the ballpark. I have not looked at how a liquid-cooled setup is configured but I keep hearing about how all this new drag is created to go along with the weight downfall. Radiators like airflow just like air-cooled barrels, but likely with different characteristics. Why do the liquid-cooled setups need more cowl opening than the air-cooleds? there is an abundance of air with a prop turning and particularly once airborn. Why couldn't a relatively simple cowl door be opened for extended ground ops and then closed to a mere sliver when airborn? Seems a radiator could be flush mounted with the cowl with airflow from inside the bay towards the outside?

Air openings needed to feed a recip engine at speed are ridiculously smaller than the average enthusiast envisions as the best design for an engine scoop. Those of us involved in land speed racing have probably taken the most note of this fact, given how important low aerodynamic drag is to performance.

Where are the aerodynamic penalties showing up? I under stand the engines themselves are heavier due liquid-cooled block and head design considerations along with radiator and coolant weight.

Looking back at your post..... Lean of proper with fuel injection? Is it already dropping rpm and running rough lean of 14.7 or so? No surprise to me.

With regard to magnetos, no they're not necessarily old, but I have described nitromethane/alcohol fueled engines as continuous combustion recips. They are as much jet engine as typical recip. They lock the timing out at something like 50 BTDC and then let em rip with downright soggy air fuel ratios given stoichiometric numbers for 'FUEL', hence the common hydraulic induced parts migrations when the fire goes out. Apples and oranges.

The point about octane is, something's amiss. A 9:1 air-cooled atmospheric engine shouldn't need 100 octane at any altitude let alone 5-10K feet, unless there are other considerations that need to be given to air-cooled operation over liquid-cooled. You mention a future aviation unleaded in the mid-90s octane rating. Hadn't heard but sounds good to me. Time to catch up to the present, for Pete's sake NASCAR did a while back even with their old school pushrod cabureted setups.

You mention light props on PSRUs. Definitely needs to be improved upon and monitored. Diesel automotive? How about a nice hub with ample bearings between the crank and the prop, instead of gears and pulley and belts etc.? I'd like to see a listed weight for the new diesels. I doubt they're more than 100 pounds heavier than a gasoline version of the same config/displacement. I realize 100 pounds is very significant, but that was the outside of my guess.

From what I'm reading and soon to experience, Lyc might drink my milkshake, though I don't remember that ever happening back in 90/91, but it seems they will definitely shake my milkshake to a greater degree than a Subaru. ;)

To reiterate, my main technical interest is in getting to the bottom of the drag debate that keeps coming up. You indicate diesel ecomomy is no better than equal due to cooling related aerodynamic drag and prop considerations. I estimated a turbo diesel could be run at similar speeds to a Lyc, I find it hard to believe that enough drag can be created by cooling system related aerodynamics to reduce 'fuel economy' of an airplane by 30% more or less. However, I'm open to enlightenment.

Geico266, I understand your points. I agree many students should not be initiated with miles per gallon in an airplane for reasons you state. However, I'm not a student. When it comes to practicality of incorporating an airplane into someone's daily or semi-daily life, miles per gallon comes into play regardless of what winds are doing in the equation. You mention driving be cheaper. I agree, I daily drive an 02 TDI Volkswagon. 99+ % of the time I'm driving down the freeway I've got a lower fuel cost per mile than anyone in sight, even with higher diesel prices. With diesel where it ought to be and probably where it will be in the next 5-10 years, things look even better.

What I am considering is using an airplane as an outstanding recreational vehicle, which I can think of 1000s of potential uses for. Beyond that I would consider using one to fly from personal property to an airport where I work 50 miles away. The idea of being able to enjoy flying, not being tied to an airport for storage or a runway for that matter and then pulling up to work without driving, 50 miles away a half hour later, after getting 25-30 mpg at 100 mph on top of gaining flight time for potential future benefit, is to say the least, enticing.
 
Something else I meant to mention, but might as well mention separately given the length of my post, is engine durability.

GMCJet, you mention Lycs spinning all day long at 2700 rpm or therabouts without blinking. What rpm could a typical Lycoming run at if it were geared down similarly to a Subaru? Are the crank, rods, valvetrain etc, OK to turn 5000 indefinitely if only their associated induction system and prop drive were set up to keep things copacetic? Or is their 75% power, or whatever, rpm in fact roughly (not exactly linear relationship between power% and % of redline rpm) 75% of the reasonable redline rpm of a Lycoming as installed in an airplane? I am guessing they have heavy buffers built in but how much really? As much as 100LL for 8.7 compression at 10k feet?
 
FlightOps said:
Is LOP lean or proper, aka lean of stoichiometric or what?
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LOP = Lean of Peak, as in Peak EGT's Exhaust Gas Temperature. By running LOP with a fuel injected engine you can save 2-3 GPH easy with about a 20% HP drop. Easily worth $10-$15 hour, PLUS CHT's, oil temps, are cooler, and little chance of pre-ignition or detonation. (I always get those two mixed up:cool:) There is some really cool history behind running LOP also. Charles Lindburg made it famous with his crossing of the Altantic, then he passed it on to WWII fighter pilots (who then burned less GPH not better MPG's;)) to help US win the war by extending fuel range.

We're on the same page here, you just need to better understand the care & feeding of a lycosorisis.

Do a search and you'll find hours of reading.
 
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This debate is starting to get like the primer question! When somebody flies one around the world without floats I will take notice. Until then it is readily available info which engine does better. You can talk F/A ratios and oil pump clearances all day. The proof is out there.
 
Craig,

It is safe to assume you are on the air-cooled side.

Naturally there are many more air-cooled engines out there. I assume folks have flown air-cooled stuff across oceans without floats. In fact I know they have. Surely you jest in stating, because a Subaru powered airplane may not have crossed an ocean without floats, it is not up to par or with reasonable potential to be up to par with a traditional air-cooled recip.

You're out 'there'. Can I assume you're part of the proof? I haven't seen any in your post.

Look, I'm not on one side or the other, but it seems there are many traditionalists or owners of one or the other that let history bias them against a concept that is still new, but in fact working.

There have been many more small block Chevrolets than Northstar Cadillacs, yet I bet they could both power an airplane quite reliably even if the small block has a longer proven track record.

If air-cooled flat engines were better for reasons beyond their low weight, why are they not used in automobiles with any frequency? I'm hearing about dramatic aero drag losses, yet can't envision why these can't be corrected, or how they're even as great as stated to begin with.

Where are the horsepower and torque peaks for a typical (you name model and quote the figures) air-cooled recip? What components are the mechanical rev limit for the same factory specd air-cooled recip? What is that rev limit?
 
Great questions

FlightOps said:
Something else I meant to mention, but might as well mention separately given the length of my post, is engine durability.

GMCJet, you mention Lycs spinning all day long at 2700 rpm or thereabouts without blinking. What rpm could a typical Lycoming run at if it were geared down similarly to a Subaru? Are the crank, rods, valvetrain etc, OK to turn 5000 indefinitely if only their associated induction system and prop drive were set up to keep things copacetic? Or is their 75% power, or whatever, rpm in fact roughly (not exactly linear relationship between power% and % of redline rpm) 75% of the reasonable redline rpm of a Lycoming as installed in an airplane? I am guessing they have heavy buffers built in but how much really? As much as 100LL for 8.7 compression at 10k feet?
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Great QUESTIONS, almost as long as one of my post.........ha ha. I'll read and respond off list when I have time, since its a little bit off the thread of Eggenfellner products, but really great questions.

First I don't or did not mean to disparage the reliability of alternative engines. You where reading between the lines, my post was defending the Lycoming, not criticism of alternative engines, only to draw comparisons on how or why they where designed the way they are. Yes car engines often are working at very low precentage of their max power. Going down a level freeway takes what, 50 hp, may be 60hp with a headwind? A lot of econ cars have 100hp total and seem OK. Aircraft use 100% at sea level takeoff and than old as much as they can in climb until they get to 75% for cruise all day. The point is very large bore low rpm direct drive verses smaller displacement high RPM. A 360 Lyc is just shy of 6 liters. Most car engines now a days are 2 liters or 3 liters, making the same or more (claimed) HP. They have to SPIN faster and work harder to make that HP with 1/2 or 1/3rd the displacement. The Lyc is not working very hard at 2,700 rpm and is "de-tuned" to be reliable. Peak HP for a like is above redline! (Again this is not Lyc is better just a contrast to the differences.)

EFI or electronic fuel injection is relevant to Eggenfellner. They use the feature as does the car. No mixture control is attractive and in the forums been debated till the cows come home. There are some issues with "open and closed loop" operations and O2 sensors, which don't live long with Av gas.
Other folks like Real World Solutions (Rotary Engines for Airplanes) offers a controller, with a mixture control option that allows the pilot to manually adjust the mixture if they want. A different approach.

Cheers, look forward to discussing. It's a two way conversation by the way, your opinion counts and I learn as well.

FADEC, by the way is available today for your Lycoming, Aerosance FADEC (no mixture control).

Check this out, Mattituck on the left click Experimental engines, than click on TMX-360 broad band users and/or power link FADEC center middle. Look at the price list, $21,900 for a brand new Lyc IO-360, 180HP. The same engine with FADEC is $29,800. There are some builder sites with FADEC installation and one of Van's factory demo planes has this. It's avaiable for the 160hp 320 as well. My observation is one cost and second installation is a lot more sensors and doodads to mount. You also become electrically dependant. That might mean dual batteries and or dual alternators, more weight and cost? You see where I am going KISS, which you know means Keep It Simple Stupid, which is my motto.

Sometimes making it more "simple" makes it more complicated.

As far as how to set power, mixture and choose altitudes that has been discussed on the Fourm; off line we can discuss. If you are not familiar with Lycomings "Key Reprints" (which was a technical new letter Lyc published for many years by a very talent writer). You will want to check out the whole thing but "How to Lean" is under operations. I understand about the rental thing, since that is how I started and was a CFI flying about 35-40 different GA planes from C-152 to C-421 and a few Mooney's, Piper's and Beech's. Most RV'ers now put in a 8 channel EGT/CHT engine monitor, often with Fuel Flow. I flew a lot of planes with out even one EGT or CHT. But short answer fuel econ is flying slower and moving that black, red and even blue knob back. The nice thing is a RV flys faster than 99% of single engine GA fleet with much less fuel burn. (precentage a wild guess but not far off.)

http://www.lycoming.com/support/tips-advice/key-reprints/index.jsp

Search the archives of the VAF forums with "LOP" or "lean of peak" for some leaning tips and opinions.


I CAN RUN CHEAP AUTOGAS?
I did not follow you 100LL at 10k altitude comment. I'll go into my rant and rave about fuel that applies to all engines in airplanes. Most Lycs we use need 100LL or at least premium. All the auto gas STC's tend to be on lower compression engines, less than 8.5:1 CR. As far as fuel in the future, they will refine what oil they have based on the market and gas will be avaiable but cost WAY more. Most airports sell AVgas. Very few airports sell autogas; it's just not as common or even that much cheaper. One airport will not let you pump autogas unless you sign a release; I'll tell you why, but first cost or saving money. Premium autogas v Avgas is only about $1.00 a gal difference? Sometimes more sometimes less depending on where you buy. If you buy gas at the local MiniMart, hauling your own fuel has all kinds of pit falls, to save that $1.00 a gal. What about on a X-C trip, you get what you can get. Avgas at this time is NOT hard to find, it's just expensive, like car gas. If you look there are some cases where Avgas is LESS money than say Premium autogas sold at the airport. Also autogas is now being assaulted with Ethonol which is bad for planes, it holds more water in solution, has less fuel density, eats seals and worst of all, more likely to cause vapor lock (and carb ice due to aforementioned water content).

STC's for autogas in certified planes is mostly limited to lower compression slower (big cool cowl) planes and no ethanol. To me with the possibility of vapor lock (which is real even with Avgas but even more with autogas) makes this faults economy. I searched the NTSB accidents, I found a 135 or more vapor lock accidents and auto gas was involved in most. RV's have tight hot cowls. The Mooney STC (the older Carb 180HP models) failed during approval test to pass, because the autogas boiled in the carb and caused loss of power. I don't see the Lycoming being an issue. If you want a low compression 150HP engine that can run on regular autogas than that would be a good deal. You can even lower compression on a 180HP lycoming making it like 170HP and use really low octane gas.
 
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Do you want to share with the class?

deej said:
I only wish this were true, but as I and others that have had troubles with their Lycoming O320/360s have already pointed out, it isn't.

Lycomings are not "bulletproof", and you will not have "almost zero troubles". If these were true I wouldn't be out a few thousand dollars in engine repairs.

Let's be realistic. Mechanical things break, and that includes both Lycoming's and Subaru's.

-Dj
Click to expand...
Could you be spacific and tell me what is wrong. 90% of the problems I see are engines that are DIS-used, mis-used or had poor or no maintenance. Occasionally there is a oh-oops! O shucks! The biggest problem I had (actually my friends plane) was a sticking valve. We did the "rope trick" and fixed it with out removing the cylinder. It does require rocker arm removal. A sticking valve is from deposits on the valve guide, usually running too hot and cooking the oil. That is why keeping OT's in the green is a good idea.

People don't realise the Lyc is not only air cooled but LIQUID cooled as well. That big oil cooler is the radiator, just not water. Oil is used to cool the heads and valves. Some Lycs, such as the angle valve IO360 200hp use piston squirters to cool pistons.

The near zero comment was in regards to troubleshooting during phase I, general getting the bugs out. My experience with Lycs has been good, but you have to fly them frequently. Planes sitting for 6 or 12 months on the ramp is not good. Most cars drive everyday. Can you imagine letting your car sit for a year, than starting it and going 100 mph for 4 hours, than parking it for another year, than going 100 mph for a year. BTW no oil changes. The above is an exaggeration to make a point.

Yes CHT's are sacrosanct! If you can keep the CHT below 400F (which should not be hard) and oil temp below 210F you will save wear and tear. Also flying at or below 75% is goodness. Some water cooled guys say water cooling is better. I AGREE, BUT......often water cooled planes have temp problems because of the radiator size compromise. I will say the shock cooling aspect of it is better. That is why glider tow planes or parachute jump planes might benefit from a water cooled engine. For a general sport plane like a RV, water cooling is not an advantage in my opinion.

If you are having problems I am sorry you are having problems. :(

I love the plane for sale, only 300 hours on the engine in 15 years!
 
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CraigC said:
This debate is starting to get like the primer question! When somebody flies one around the world without floats I will take notice. Until then it is readily available info which engine does better. You can talk F/A ratios and oil pump clearances all day. The proof is out there.
Click to expand...

This debate has been going on for many years on this forum! It will continue. Do a search on alternative engines and you will get a very good education on auto engines in airplanes.
 
Interesting..

....article in Sport Aviation about the replica Wright Flyer actually flying....aaaaand, it has a PSRU, just like the original:D

Regards,
 
Since this thread is hopelessly off topic I'll add my 2 cents worth.

If you want a real aircraft engine..........................
100_2696_Small.jpg


Gets reasonable MPG GPH or however you want to measure it performs well and looks and sounds sexy.

Hopefully one day Van will make and RV for Radials.
 
Low power/displacement doesn't typically lend itself to low BSFC

Not really true...an engine is most efficient at its TORQUE peak, not its hp peak.

The large displacement engines are strickly optimised for a very narrow RPM band and are actually very efficient in the 2300-2700 rpm operation because they are at or near the torque peak or point of highest volumetric efficiency.

As to the draq issue...

The issues is that if you have 1000 calories of heat to disipate, it takes less air to do it when the difference between the air and the hot surface is greater...that is, heat transfer increases as a function of delta t. So 60 degree air over a 380 degree cylinder can remove more thermal energy with less air, than can 60 degree air across a 190 degree radiator. The other issue is that heat transfer is never 100% efficient and the more you do the more excess energy must be displaced...so in a water cooled package the heat must transfer from the aluminum engine to the water, then from the water to the aluminum radiator, then from the aluminum radiator to the air.

It just takes more air. When a plane is specifically designed around the ducting, improvements can be made, and very successfully, but it is a design from the start approach.

I would encourage you to evaluate installed performance...because the installation as a whole matters.

As to lycoming reliability....everyone can throw out an example of a failure, but the fleet soldiers on with the vast majority trouble free.
 
I was actually surprised researching the NTSB database last week to learn how many certified engines suffered catastrophic internal failures (rod, piston, crank, dropped valve, blown jug, oil pump etc.)- not related to maintenance issues. I found 72 in the last 5 years with a simple search and 181 total failures with the same search not due to fuel exhaustion or ignition system malfunction. If you search "engine failure" for the last 5 years, there are 278- many of these are due to fuel exhaustion which can't be blamed on the poor engine. Many will say that there are tens of thousands of piston engines flying in the US. True, but these numbers are still statistically significant. The Aviation Consumer magazine drew similar conclusions in some of their model evaluations.

For Subaru, we find 23 in the same period and zero internal catastrophic failures. All these failures were due to supporting systems and poor maintenance- very similar to the majority of certified engine failures. The point here is that there were no core failures.

So the term bulletproof does not seem to apply to Lyconental engines and the stats are sobering to all those pilots who think that engines rarely fail. Engines of all types can fail for a variety of reasons- the reason is not really important to you when your prop stops.

The cooling drag contention cannot be decided on by fundamentally flawed assumptions as I've said before. The efficiency of heat dissipation from an air cooled cylinder head and a modern radiator are somewhat different. Delta T is only one part of the equation. Radiators are many times more efficient per unit area and unit volume than cooling fins and properly ducted rads offer a far more efficient heat transfer vs. drag process as well. Liquid cooling is better at removing heat from critical areas such as combustion chambers and exhaust valve seats and permits far higher power densities.

I have presented historic proof that liquid cooled engines of similar hp in otherwise identical airframes from the WW2 era were IN EVERY CASE faster than their air cooled counterparts. I guess this data is simply ignored. How a well designed liquid cooled installation in an RV would stack up against an opposed air cooled installation is unknown as nobody has ever tested the concept properly. We have no data to support either's superiority at this time.

Both concepts work obviously and both have their pros and cons. I enjoy flying my Subaru RV just as much as my friend down the taxiway with his Lycoming powered one. I think this is the most important thing.:)
 
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