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f1rocket

Well Known Member
Okay, this is the debate section, right? So let's entertain a discussion regarding alternative engine options.

I did a little research. I looked at all the RV accident reports for 2004 and pulled all the "engine problem" ones. I found 7 accidents. 5 of the seven involved Lycoming engines, 1 involved a Subaru, and 1 involved a Chevy V8.

Within those categories, I looked at final reports to see the root cause of the engine problem. On the Lycoming, 1 is a preliminary report so I don't know. 3 were caused by fuel exhaustion, 1 by a oil cooler line failure. None were caused by any internal engine problem. The Subaru went down due to vapor lock at cruise. The Chevy went down because of internal engine failure of the main bearings.

What can one derive from this? Not much really, but you can extrapolate some indications. When you consider the tens of thousands of hours put on Lycomings each year, it sure looks like the Lycomings are pretty reliable as long as you feed it fuel and oil. When you consider the very small number of hours put on alternative engines in a year, the picture is less rosy.

I guess that's my point. If you chose to drop an alternative engine in your RV, be sure you're willing to accept the proposition that you are a powerplant test pilot. Just because there's a few Subarus, Mazdas, and Chevys flying successfully, doesn't necessarily mean that your usage will be trouble free. There aren't enough hours put on these engine to derive any meaningful statistical conclusion as to their reliability. I'm not saying that they aren't reliable, and I'm not saying that they are. The point is there's no numbers to prove it one way or the other. If you can live with that, then go ahead and experiment.

One of the reasons folks choose the Subaru package, in particular, is cost. I suspect, but would like to see some hard numbers, that when its all said and done, you will likely have nearly as much money in a Subaru package as you will in a Lycoming. And don't quote me prices on the NEW Lycoming, because you're not getting a NEW Subaru either. You're getting one out of a salvaged automobile. When you consider resale value of your RV, I bet that Subaru will cost you much more money in the long run.

I'm a chicken, I admit it. When it comes to swinging the prop around, I don't mess around much. People have been trying to convert auto engines for aviation use since the 1960s. Personally, I don't think there's any magic out there to be uncovered. I have confidence in my building skills so I'm not afraid of pulling the wings off or losing my tail feathers. But when the prop stops turning, I have a big problem and a heavy glider on my hands.

I think there's more promise with newer designs like the diesel and turbine engine prototypes. In the meantime, I think I'll stick with what has a proven track record of reliability. I admire all you test pilots, and I hope your projects are very successful and safe.
 
You're a Test Pilot Every Day

Everytime you go up in a plane -- even a passenger airliner -- you're putting your life in someone else's hands.

You're placing your life in the hands of of, occasionally, disgruntled aircraft mechanics or over-worked ATC's and the only protection you have is tonnes and tonnes of government regulations, drafted by other disgruntled government employees, many of whom aren't pilots, that you hope they follow.

The aircraft industry is stagnant. Concorde is dead, the "new designs" coming out of Boeing and Airbus are just larger re-hashes of 30-40 year old designs.

GA is even worse -- there hasn't been a significant innovation in GA design for 35 years. Cirrus is a nice, old design, with new materials, but at $400,000 a pop, not many of us will be flying them soon.

In comes the Kit Plane industry -- Innovation, intelligence, ingenuity and affordability. And, all it asks in return is that we take personal resonsibility for our choices. No lawyers, just men, women and their minds -- and, in some cases, their bodies. The Kit Plane industry will save GA from itself -- if we can keep it free.

We are ALL going to have to make tough decisions about our powerplants in the not to distant future when 100LL is no longer availiable -- that is not an "if", it's a "when". Lycoming and Continental aren't telling us what plans they have, if any.

There are a few alternatives on the horizon down the certified path, Wilksh, SMA, Centurion -- all expensive and all unproven by large statistical samples.

Automobile engines are, for many reasons, superior in all ways (performance, reliablity, economy) to the 40 year old designs coming out of Lycoming and Continental. Automobile conversions have not, traditionally, been very successful. Mostly because conversion were undertaken not to provide superior performance, but to provide a "cheap" alternative to certified engines.

There are engineers out there now, who are creating high-quality, high performance, but not necessarily lower-cost conversions that, in at least one case, have been achieving their goals.

Everyman has to make his own decision on what risk he's willing to take. You do the research, you talk to the engineers (When was the last time you got the lead engineer from Lycoming on the phone?), talk to those flying the engines, get the data -- then use your own brain and make a decision.

There is a movie, based on a famous book, called "The Fountainhead". A brilliant architect, named Howard Roarke, designed buildings based on new materials and new technologies. He refused to make them look more safe and familiar by incorporating useless classical additions. Everyone said his building would fall, that they were unsafe, but they stood and were magnificent.

No one will deride you for taking the safe, certified path -- and many will deride you if you take the Howard Roarke path. But ultitmately, it's a personal decision. You have to ask yourself, why are you flying a kit plane instead of a certified Cessna 150?
 
eSubie's

Actually the newer model eSubie's (Eggenfellner) are new engines, not used engines.

There are advantages and disadvantages in going with either the eSubie's or the Lycosaurus. The eSubies can provide real heat to the cockpit. There is reduced complexity in the cockpit with no mixture controls to worry with or prop controls either. Then there is the easy installation; hooked up and runnng in a day or less (plug and play). You also have the option of boosting with a supercharger to maintain power at higher altitudes.

$ for $ even if the eSubie's may be comparable in price they do offer some advantages that the Lycosaurus does not.

In the end I may very well use a cheap used Lyco. But it'll be just because of the lower up front costs. That doesn't mean I believe it's actually the best solution.

Now if I could afford a new lyco then I'd be hard pressed not to get an eSubie instead!
 
Oh boy, where do I start.

Automobile engines may be of a higher technical level than a Lycoming, but they are NOT superior when it comes to driving an airplane through the sky. Take a look at the main crank bearings and the engine block of a Subaru and compare them to the Lyc. When you are swinging the weight of the prop out front, it requires some hefty support. Lyc's also deliver peak power at low RPM, while the Subies need to scream along at much high RPM to deliver peak horsepower, hence the gear reduction units. I contend that automobile engines are very poor airplane engines because they need to be jerryrigged to make them work.

The benefit they have is that they are cheap because they are mass produced. Can't beat that. They also have great reliability when used for their intended and designed use. Start sticking them in airplanes and you are bringing along a whole additional set of engineering problems to be solved. I don't know any engine engineer that thinks gear reduction units are the best way to turn a prop. No, it's just a band-aide stuck on an engineering problem that otherwise, can't be fixed.

The whole 100LL thing has become the enabling battle cry of the alternate engine groupies. Unfortunately, it doesn't hold water. No one is going to wake up one moring to find that hundreds of thousands of engines that use the product suddenly are silent because no one is making it any longer. I don't doubt that there will be a transition to other fuels in the long run. That's probably why the diesel engine is looking like a viable engine alternative. But you and I will be able to buy 100LL for many, many years to come. Now the price of that gallon of 100LL may be another issue.

Finally, the reason I fly a homebuilt and not a Cessna 150 is because I can upgrade my Lycosaur with electronic ignition, FADEC, etc and get the best of both worlds----newer features and capabilities with proven reliability.
 
Where are the rebuttals??

This is a good thread and I am surprised that others haven't chimed in by now. I am not an engineer so I cannot provide objective data, frankly I haven't seen a comparison, but here are my thoughts, whatever they are worth.

Automobile engines may be of a higher technical level than a Lycoming, but they are NOT superior when it comes to driving an airplane through the sky.

Maybe not superior but I don't feel they need to be considered inferior either. They are the product of years and years and years of engineering by some of the best engineers in the world and by companies with very deep pockets. They are outstanding machines and I see no data to suggest they are inferior when it comes to moving an airplane.

Take a look at the main crank bearings and the engine block of a Subaru and compare them to the Lyc. When you are swinging the weight of the prop out front, it requires some hefty support.

Agreed, it does take support. But just looking at the physical size of the bearings is not all that needs to be considered. The Subaru has more bearings and they are spaced much more closely together. This provides for a great deal of support and also makes for a smooth running engine capable of very high RPMs. In addition, PSRUs actually help provide support and also isolate the engine crank from a lot of abuse. Finally, combine these super smooth running engines with a well balanced lightweight prop and a lot of the abuse is eliminated. I agree that with all else being equal (which it isn't) a Lyc would seem to be the sturdier of the two, but when the entire package is considered, the auto engines actually punish the components and the airframe less and therefore may even be superior.

Lyc's also deliver peak power at low RPM, while the Subies need to scream along at much high RPM to deliver peak horsepower, hence the gear reduction units. I contend that automobile engines are very poor airplane engines because they need to be jerryrigged to make them work.

Yes and no. Yes they do run at high RPMs, they are designed to run at high RPMs. This is not in itself a negative. Running an engine at 3500-5000 RPM that can run easily at 7-8K is not a big deal. I don't view a PSRU as a "jerryrig," we have been using geared units on cars for decades (we call them transmissions and differentials) and they seem to work pretty darn well. Sure it is another point of possible failure, but the history is pretty good on them so far. Granted they don't have the history of the Lyc but they seem to be pretty good non the less.


The benefit they have is that they are cheap because they are mass produced. Can't beat that. They also have great reliability when used for their intended and designed use. Start sticking them in airplanes and you are bringing along a whole additional set of engineering problems to be solved. I don't know any engine engineer that thinks gear reduction units are the best way to turn a prop. No, it's just a band-aide stuck on an engineering problem that otherwise, can't be fixed.

Yes the auto engines certainly are more economical and they are very reliable. Although the initial cost is about the same, this is more a result of the number of suppliers and engineering start up costs. These costs will come down as more are produced and FWF packages are finalized. But even at current costs the fuel cost savings of a conversion over the life of the plane will be very significant. Yes resell costs may be lower, but then again, maybe not 10 years from now. But who cares? If you plan to sell your plane in a year or two it may make a difference, but if you plan to fly it for 8-10-12 years or more, you make up that difference in fuel costs alone. Run the engine out and if the buyer wants a Lyc 10 years from now, let him strap one on and go. I don't agree with the "bandaide" reference. It implies a temporary fix to something that is broken. Sure the conversions are a different solution, but I don't see any evidence to support that they are a broken or substandard solution. I guess I will take your word on the engineer comments, I have not seen any polls on the issue. I am curious about how many engineers you have queried and why they feel a PSRU is not a viable solution.

The whole 100LL thing has become the enabling battle cry of the alternate engine groupies. Unfortunately, it doesn't hold water. No one is going to wake up one moring to find that hundreds of thousands of engines that use the product suddenly are silent because no one is making it any longer. I don't doubt that there will be a transition to other fuels in the long run. That's probably why the diesel engine is looking like a viable engine alternative. But you and I will be able to buy 100LL for many, many years to come. Now the price of that gallon of 100LL may be another issue.
Finally, the reason I fly a homebuilt and not a Cessna 150 is because I can upgrade my Lycosaur with electronic ignition, FADEC, etc and get the best of both worlds----newer features and capabilities with proven reliability.[/QUOTE]

Maybe yes maybe no. While there doesn't appear to be any indications of a shortage of 100LL anytime soon, we just don't know what the future will bring. You state that we will be able to buy 100LL for many, many years to come. I am not sure how you have reached this conclusion, I don't see any evidence to know one way or the other. I think we all agree that there is some pressure on 100LL. What that pressure will bring or how long it will take is not known but I suspect that it will not result in better availability or lower prices in the future. As far as EE, Fadec, etc. these are certainly not advantages over an auto conversion. The auto engines were designed with these features in mind from the ground up. I guarantee that GM and Subaru have put tons of more money into engine control research than all of the FADEC suppliers put together. I think it could be argued that adding FADEC to a Lycomming is a bandaide approach to engineering compared to the auto engines that were designed from the ground up with them in mind.

The biggest advantage I see to a Lyc is simply availability. They are available everywhere. Parts are readily available amd you can get them worked on at almost any airport. You can buy auto engine parts off the shelf but finding FWF parts for them at remote airports and finding someone to put them in for you might be a challenge. This will change as more and more become in use. Hey at one time I bet finding Lyc parts and someone to work on them was tough also.

The biggest advantages I see to conversions is that they represent the latest and very best in engineering, they are water cooled and they run super super smoothly. I hear people talk about a smooth running Lyc but compare it to the audio on Jans web site of the Subaru and then tell me in good conscience that a Lyc runs smoothly.

I compare the Lyc to a Subaru as a Harley to a Gold Wing. They will both get your down the road. The Harley has a cool factor to it and its long heavy stroke creates a not so smooth ride. The Gold Wing, on the other hand, may not be as cool or may not have been around as long, but it will get you where you want to go using the latest in engineering technology and it purrs like a kitten.

Bottom line is they will both get you to your destination and pretty darn well. Some like the features of the new engines and the excitement of trying new technology, some are more comfortable with the proven Lyc. To each his own.
 
dropping the kids off in your RV?????

I was really interested in the subject a few years back. I wanted to believe that a modern car engine was better. It didn't really take long to come to a conclusion once I really thought about it.

First of all I work as a vehicle dynamics engineer in the auto industry. I'm out every day pounding cars on the test track. One thing is very clear when you are driving a car at 100% all day (most people only drive at a small percentage of that, eventhough they may believe they drive around fast). Not all engines and transmissions are the same. They are built with specific jobs to do. For example, the Toyota V6 gas engine is a great car engine. When they stick it in the 4Runner it's a real piece of junk, the torque is way up high, you can't pull up a hill at all unless you slip the clutch. It was not made for that application so it fails at being a truck motor. Take a look at the Ford 6.0 Deisel, they are a great truck engine. Really stink for soccor moms driving kids around town. Drivability is very poor compared to a quick responding gas motor.

The point is, airplane engines are basically generators. They cruise along at a constant speed, don't require any transients. Except for a couple of deisel truck engines, the typical car engine just isn't made for that. Even a Vette motor can't take high speeds for more than a minute or so. (Before I get a bunch of bowtie poeple yelling at me, I've broken more vettes on a track that you can imagine) And all those Honda, Nissan, Toyota, Subaru guys, yes they have all been towed off the track with broken motors from sustained high engine speeds.

So in conclusion I chose to go with an airplane engine. You enjoy whatever engine you pick and I wish everyone a great time flying their plane. Just please stop argueing that a car engine is made for sustained high engine speeds and power, it just isn't. They are made to make soccor moms and Uncle Sam happy not to power generators.
 
Engineering?

Tom Maxwell said:
Maybe not superior but I don't feel they need to be considered inferior either. They are the product of years and years and years of engineering by some of the best engineers in the world and by companies with very deep pockets. They are outstanding machines and I see no data to suggest they are inferior when it comes to moving an airplane.

Tom Maxwell said:
The biggest advantages I see to conversions is that they represent the latest and very best in engineering, they are water cooled and they run super super smoothly. I hear people talk about a smooth running Lyc but compare it to the audio on Jans web site of the Subaru and then tell me in good conscience that a Lyc runs smoothly.

We need to make a very clear distinction between the engine core, supplied by the automobile manufacturer, and all the essential accessories and mods that are required to create an aviation powerplant.

The automotive engine core is likely very well engineered, and may be extremely reliable, even when used in a different mission than it was designed for. But, every automotive conversion I have seen had a number of essential items that were either designed by the builder or the conversion manufacturer (e.g. reduction drive, cooling system, fuel delivery system, etc.). These essential accessories are not nearly as well engineered as the engine core, yet a failure of one of them has the same effect as a failure of the engine core. For example, a local RV-7A builder had an engine failure (one of the more popular automotive conversions that is touted as running very smoothly) that was due to vapour lock due to a design problem in the firewall forward kit. The conversion manufacturer acknowledged a design problem, and later provided a modified part. The builder sold the aircraft, and is building a new one, which will have a Lycoming. I am aware of an Mazda rotary powered RV that had an engine failure due to a problem with the builder installed carburetor. Another RV had an engine failure when the supercharger belt came off in flight.

So, don't think that the "superior" engineering of the engine core necessarily translates into higher reliability than you would get with a Lycoming. If you want to install an automotive conversion, it's your aircraft, do what you want. But please don't kid yourself that you are doing it to get higher reliability.
 
Yes Indeed

I agree, the whole package needs to be considered. These conversions are pretty new and with any new endeavor there are going to be start-up issues and engineering issues to resolve. Although I am much to young to know ;) , I think there must have been issues with the first Lycomming engines as well. There are probably some on these boards who can tell a few stories about early Lycomming engines.

Things do happen with machines, no question. The examples you cite seem to me to be problems that could have happened with Lycommings as well. I've heard stories about vapor lock and carb problems on Lycommings and I guess it isn't to far fetched to believe that a belt could break on a Lycomming supercharger. One of the first RVs I saw "live" was under repair following a forced landing. In talking to the owner, he said that a bearing had frozen and the piston rod twisted off. I guess what I am saying is that yes stuff does happen and it isn't limited to new packages. Frequently, the failures are not with the core engines at all but with the supporting equipment. I would expect to see more issues with these new package than with Lycomming packages and I expect the new packages to improve over time. Only time will really tell if these packages are realiable and if they are good alternative. I am sure there are thousands of Lycs flying and they have been for 30 years. In perpective I think Jan has 300+ Subies flying with only a few years of experience. We will see where it all leads.

I will definitely concede that a Lycomming is a proven workhorse and a safe choice. Much like choosing IBM in the 70's and 80's. I once had an executive tell me, "IBM may not be the best solution, but I won't get fired for choosing IBM." Today choosing an IBM alternative is not considered risky at all. I understand that everyone has different comfort levels, so to each his own. I fault nobody for not jumping on the wagon or for waiting until the new packages get more time and become more proven. Some will elect to be a part of the journey and others will sit back and watch, and that is OK.

What do you think about the Lyc alternatives. Are they better or just-as-good or do they have issues that make pure Lycommings better?

As I said, I am not an engineer so I do appreciate the engineering perspective and your thoughts. Thanks for you input. I would be interested in hearing what the failures were in the auto engines after running them for long periods of time at high speed and how the engines might be improved to handle it. Or is the only answer to piston powered flight a long, hard, slow stroke and lots of beef to handle it?

Thanks again for the discussion.
 
Tom Maxwell said:
What do you think about the Lyc alternatives. Are they better or just-as-good or do they have issues that make pure Lycommings better?

A couple of weeks ago, the differences between how Lycomings are built and the things that are different when building the same base design but by different companies (Superior and Mattituck) were posted on the Lycoming Yahoo group.
There's a good handful of improvements that the two other builders have done to their engines and they all make lot's of sense.

Are they better than the Lycoming brand?... I don't know, but the improvements do seem to be geared toward dependability and durability issues so the answer is; maybe and/or probably if the improvements really DO add dependability or durability to the basic design .

And something else that should be said about the "60 year old design" still built by Lycoming and now the same design used by other companies is that there have been major advancements in the areas of metallurgy and other areas of engine design that weren't around 60 years ago.
Those advancements give us things like Nikosil lined cylinders, flow control for smoother running, and better implementation of internal oil dispersion and stuff like that. Those things, as basic as they are today, were not likely incorporated to any great degree in the original Lycoming design.

So perhaps the Subie and Mazda fans might consider that the basic mechanical design of the "old" Lycoming type engine, coupled with modern materials and engineering of things not even thought of 60 years ago, make the Lycoming a better and more reliable choice than the car engine people like to think.

Vern
RV7-A
 
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I don't know the reason other people want an alternate engine over Lycomings but the reason i do is smoothness. It doesn't mater how much modern materiel you put in it is still going to be a big bore strong pulse thumper.You can't make a Gold wing out of a Harley. I presently fly a Kitfox with the Rotex 912 and have had a lote of comments on how smooth it is compared to Lycs. I don't know if i will go with a auto converson,probably the Deltahawk if it works out but not a Lycoming :mad: unless they are giving them away.Once you've flown smooth you will never go back.The airplane might like you better to :)

Darrell RV9A
 
Needs of alternitive engines

Ok group,
The real need is to determine how an engine was designed to be used. I'll try to be brief. Orrenda proved that parts availability isn't everything when 40 mil was spent trying to build a Small-block airchevy. The auto V8 has a lot of problems, (like bearing area) when converted to aircraft use. Even the mighty Japanese giant Toyota gave up on it's Lexus based V8. No takers with the 400 hour TBO! Some engines are better than others for conversion. The Little Subie with a 5 main bearing bottom end is much better suited to 100% operation. When properly mated to a good PSRU it shines. Don't forget that engines like the RR Merlin were gear reduced, likewise many of the large radials. I plan to use a rotary (Wankel) in my RV-10. The rotary probably makes a better airplane than car engine. The devil is in the details, Mistral of Switzerland and Florida are certifying a rotary. The biggest problems are in the ancillary systems, can you use the auto injection and engine management systems? Can you design a good redundant system? Like the argument about steam gages or an all electric panel arguements can be made for both sides. If you aren't capable of doing some of the design work yourself you should probably stay away from conversions. You need the skills even if you buy the package to determine if the seller knows what he's talking about. If you are up for that challenge then good carefull design will produce a good flying plane.
Bill Jepson
 
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Zoom Zoom Engines No Free Lunch

Darrell514: "I presently fly a Kitfox with the Rotex 912 and have had a lote of comments on how smooth it is compared to Lycs."
There is a big difference between 80HP and 180HP.

Tom Maxwell: "The biggest advantage I see to a Lyc is simply availability."
Absolutely, just about any airport you land at with service will have a mechanic that is familiar with Lycs and have tools and parts for them. Yes there are many car dealers but not on the ramp of airports. That is why autoengine RV?s may not have as good resale. People who buy 2nd hand RV?s will not likely be as apt to work on them nor can they legally do more than part 43 appendix A. Getting a local A&P or AI to work on your Eggen RV, because of lack of familiarity, parts and liability may be a problem.

F1rocket: "Finally, the reason I fly a homebuilt and not a Cessna 150 is because I can upgrade my Lycosaur with electronic ignition, FADEC, etc and get the best of both worlds----newer features and capabilities with proven reliability."
Absolutely, A Lyc has choice of several electronic ignitions, fuel injection, FADEC, exhaust systems and many fixed and constant speed Props. Auto conversions are limited to single supplier for parts. As far as props, the auto engines use fixed or (EXPENSIVE) electric propellers. I?ll just say electric props with slip-rings and brushes, some with ultra-light pedigrees are not in the same league with hydraulic controlled props. In my opinion Hyd beats any Elect prop in maintenance, reliability and control. Hydraulic props have decades of experience and testing. With an electric prop, you are the test pilot. With a fixed prop the Subie takes a further hit in performance because it needs the RPM for power.

F1rocket: "Automobile engines may be of a higher technical level than a Lycoming, but they are NOT superior when it comes to driving an airplane through the sky."
Absolutely, people have the idea that Lyc's are stamped out by a Black Smith with a hammer, anvil and an open fire. They use state of art CNC, materials, processes, tolerances and manufacturing controls..

bhassel: "Actually the newer model eSubie's (Eggenfellner) are new engines, not used engines."
Uhaa, You can buy a brand new O-320 fixed prop, outright from Aerosport or 6 other places for $18,500, with all the accessories. You bolt it the engine mount that came in Van?s kit, add a $2000 fixed prop, one or two grand for exhaust and other stuff and be done. What does an Eggenfellner cost? About 30-40 Grand by the time you buy everything including prop ($8K). I would say the fixed prop O-320 will out perform the normally aspirated Eggen and be lighter by 50-100lbs. The Cost advantage of the bolt on alternate engine kits are an illusion.

Bhassel: "The eSubies can provide real heat to the cockpit."
Uhaa I have a heat muff. Aircraft Exhaust Technologies, Inc made my exhaust. They welded little ?heat studs? like a porcupine on the pipe where the muff wraps around the pipe. I can roast marsh-mallows with it.

Bhassel "There is reduced complexity in the cockpit with no mixture controls to worry with or prop controls either. Then there is the easy installation; hooked up and running in a day or less (plug and play)."
I understand the idea of a single lever control like a jet, but really is this a big burden? I don't find it a problem moving the throttle, mixture and prop cont'ls. I have seen Subie engine installations and they look more complex than a Lycoming to me. I think you can run a Lyc with two wires, three push-pull cables and a fuel line. No redundant electric fuel pumps, electric water pumps, dual electrics-batteries, water hoses and radiators. Plug and Play and Play and Play A-lot. I say if you want to fly and not tinker, use a Lycoming per Van?s plans.

Bhassel: "u also have the option of boosting with a supercharger to maintain power at higher altitudes."
Uhaa, You also have the same option with a Lycoming, and your point?..
I agree you can get more performance at high altitudes with a turbo charger. You will be sucking O2 thru a mask to use it; you have to go to 12-13 grand to see the turbo benefit. A Gent in Canada made what I think is an exemplary Custom Subie installation with a turbo. Well designed, tested and built. A fly off between two RV-6A?s, his Turbo Subie and a 180HP Lyc powered one, gave a slight edge to the Lyc until about 12K feet. At 12k the turbo Subie had 1-3 Kts and a little more fuel burn over the Lyc. (No free Lunch.) That is pretty good for an engine with 1/2 the displacment, but of course he needed 35" boost & 4800RPM get the job done. This was NOT an Eggen installation but a custom design. The builder clearly has more ability and resources than most builders do, including me. You want to go fly, bolt on a Lycoming. You want to invent and design and tinker, by all means build your own installation.


Bhassel: "Now if I could afford a new Lyco then I'd be hard pressed not to get an eSubie instead!"
Bob, price it out. Look at the prop, the kit the real cost of Egg or whoever kit you buy. Than look at a Lycoming, I don?t see a big cost savings. Now if you are going to roll your own Subie or better a Rotary with ?Real World Solutions.? That is a different story. We are now talking sweat equity. Again fly or tinker, your choice. You still may end up with something that is heaver, slower and not that much cheaper.


Fredmoss: "Every time you go up in a plane -- even a passenger airliner -- you're putting your life in someone else's hands."
What does it have to do with Auto engines in airplanes?
It is 4 times safer to fly on an airliner than to drive.
It is 26 times safer to drive than fly in a general aviation private plane.
It is 104 times safer to fly an airliner than fly in a general aviation private plane.


Fredmoss Automobile conversions have not, traditionally, been very successful. Mostly because conversion were undertaken not to provide superior performance, but to provide a "cheap" alternative to certified engines.
"Automobile conversions have not been successful in improving performance because there is no Free lunch. They are limited by the same physics as any engine. Typ alternate engine installed real weights are more, they have less ?real? HP at the prop and burn as much or more fuel per HP. The fastest RV's still have Lycs." :D

Subie is an internal combustion 4 stroke, overhead valves & cams, water-cooled auto engine. No quantum leap in technology here. Auto engine electronics are for fuel economy and emissions, where you go form idle to max load, back to low power over and over. Electronic technology for airplanes is available and works, but the advantige in an aircraft is not as great as for cars. The Lycoming, does not need overhead cams or water cooling. It is a light weight, low RPM, high torque, air-cooled engine for an airplane, designed to direct drive a prop at steady RPM. Water cooling is better in controlling cylinder piston tolerance which improves emissions. Lycs don't have emission requirements. Look at the real empty weights of finished RV's with a Subie. They weigh the same or more than a typical 200hp Lycoming (which are heavy) with a Hartzell constant speed prop, but the actual performance is more like a 150/160hp Lyc.

The Mazda seems to be a better choice of the ?alternative engines.? The Mazda has it?s own set of rules. Go to the Guru of rotary, Tracy?s Real World Solutions. http://www.rotaryaviation.com/ For someone who sells rotary engine conversion components, he is about as fair, rational and honest about this alternative engine as anyone. PLUS most important he actually fly?s his product. ;) If I wanted to tinker and might save a little money in the process, go with the Rotary. I don?t. That is why I have a Lycoming O-360. As far as money I bought a core, overhauled it with new parts and ended up spending about $10-11K on the engine/carb."


Cheers George :D
 
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To me, any questions I had about the suitability of using automotive engines in Aircraft was answered four years ago in an article that appeared in Sport Aviation. It was a feature on Jim Rahm's beautiful 420HP Lancair IV. Jim used a V-8 designed and build by Al Joniec, a veteran NASCAR guru. The first thing that Al said was he had spent his automotive career trying to get Detroit steel to run at 100%+ power on race tracks. The problem, he stated was because auto engines rarely are run at 65% power. They spend their time much lower power settings. At highway speeds, they are putting out 17-22%, depending on the gear train and automaker. During a jackrabbit start, 100% is for a few seconds, and as higher gears are selected, the engine is below 50% rapidly. Asking a stock auto powerplant to sustain 100% power for climb then 75% in cruise was an exercise in accelerated life testing, according to Al. For Jim's Lancair, I believe he chose a Chevy boat racing engine lower end, due to the sustained high power output demanded by power boat racers.

I agree that auto engineers are pushing the electronic envelope in ignition and fuel systems, and that's great. I wish Lyc and Cont. would follow suit. The reliability of modern electronics keeps getting better and better, which is why we have so many radio options now avialable to us.

However, for me, the 'rubber meets the road' on the durability of autoengines question. They are not designed to run a long time at over 50% power. That cinches it for me, water cooled or not, electronic ignition or not, better cabin heat or not, single power lever or not. If the crank, case and bearings are not going to hold together for 2000 hours running at 65%+, it's not the engine for me. I think that the post by the gent who tests cars for a living bears this statement out.

That being said, I encourage all of us to fly what we like best, and to enjoy it fully. For my mission, which is reliable long distance IFR transportation, I'm installing a Lyc. I've got 2200 hrs flying behind one and it's never let me down or left me stranded....
 
Good Discussion

I guess a big issue in trying to argue on behalf of conversion packages is there just isn't enough information or history to support it. It is pretty easy to argue the history and peformance of the Lycs and Lyc-a-likes but not so for the conversions.

There are a significant number of people who argue that auto engines are not engineered for this kid of abuse. I guess those of us who are not engineers and do not know what "engineered for aviation use" vs "engineered for auto use" really means will have to take their words on it, and it may well be true. But there is another group of individuals who feel differently and are forging ahead and trying these alternative solutions. Can't really fault them for that either. This group seems to believe that the auto engines are more than capable of being a reliable source of aviation power. Only time will tell for sure.

I think the Egg package is probably the most well known and most prolific of all the conversions. While the firewall forward package does create some very exciting challenges, I think those leaders in this arena are pounding out good solutions and finding better solutions every day. One of the reasons I think Jan is being successful is that he does look at the entire package and he isn't just throwing an engine out there and leaving the rest to others. He is constantly looking for better ways to do it. Some like being on this leading or bleeding edge, others are not comfortable with it. There are getting to be a significant number of flying Eggs and they are starting to rack up some hours. Again, I don't have hard numbers but I think there are a few Eggs near 1000 hours and I am being told there has never been an engine or PSRU failure. Supporters see the smooth operation, lower fuel costs, and lower overhaul costs to be very appealing. Again, whether these all pan out will be proven over time.

Someone has pointed out that there have been failures in planes carrying these engines, but I believe the examples given were belts, alternators, and other peripheral failures and not engine failures. Nit-Picing? Maybe. But there are a lot of documented examples of peripheral failures on Lyc packages as well. Take a look at Rosie's post on cost of ownership as an example. Nothing on the engine, but several peripheral issues. The bottom line is that if we hang it on the engine, it will be a potential source of failure. Peripheral failures are going to happen and are not a reflection of the quality of the engine to which they are attached.

I have really enjoyed everyone's input on this and I hope others have as well. There are definitely pros and cons to staying with the tried and true and there are pros and cons to venturing off into new territory. I don't see that there is a clear winner either way, but each of us will have to weigh what we believe to be the key decision points and go from there. To be forthright, I don't know which way I will go when the decision finally comes. I don't know enough about them yet to make my decision. I have always been kind of contrarian in everything I do, though, so that may play into my decision. If it doesn't work out either way, hey it is only a $25K to $35K mistake and we have already determined that when it comes to flying money is no object. :D Just kidding!

If nothing else, I believe there is a need for competition in this market. I am excited to see alternatives come and go and think the effort will make for a more competitive and better market for all of us. You can bet the Lyc and Lyc-a-like manufacturers are not just sitting on their hands watching this happen. Competition only makes for more cost effective and better engines all around.

Thanks again for the input. It has been very beneficial to this neophyte.
 
Tom,

I thought you did a nice job of summarizing the discussion and bringing it full circle hence the title "Are you Ready to be a Test Pilot?". That was my whole point in starting this thread. It wasn't to trash the ideas of the alternative engine builders, although their ideas are not for me. It was to get folks to consider the fact that if you strap one of these on your bird, you are truly a "test pilot", perhaps more so than these engine providers would lead you to believe.

The entire engine package does not have the benefit of thousands of hours of actual flight time, so you are helping to establish the engine's reputation, rather than relying upon it. That doesn't make it bad or good, and I realize that there's no way for the alterntive engine folks to overcome it until more time is built up, so time will tell. I hope they do prove to be an economical alternative because everyone in aviation will benefit from it if they do.

I still don't believe today that the engineering data, acquisition cost, maintenance cost, resale value, performance, or reliability make the Subie a better powerplant than the Lycoming, but I'm okay if others want to believe it. Just temper the exhuberence with some tought questions and open eyes, and if it still make you smile, then go for it. Most of all, enjoy the hobby and be safe.
 
Yes Indeed

Yes indeed, I agree 100%. I think the cost of the alternative packages is somewhat of a stickler. When a full package can be had for 50%-75% of the cost of a Lyc. then the risks are somewhat mitigated and we po folks are a little easier to sway. When the cost of a package is equal to or more than a Lyc. it makes the decision a whole lot more difficult. In the end I will probably go with my gut feel. Although I love the idea of a super-smooth Suburu, something just doesn't sound quite right about running an engine at 4k RPM for extended periods of time. Time will tell and I may be swayed yet.

Of course you guys driving the rockets with the big gas guzzling 540's in them don't care about money ;). So you guys should be leading the way and trying all of these new options so we po folks will have more data from which to make our decisions. Just kidding!

Thanks for the thread. It has been very informative for me.
 
I figured that I would chime in here on a minor point, but one that was significant for me in the lyc vs conversion discussion. When I was considering the lyc vs conversion I weighed the ease of installation issue. Being a novice I was attracted to the plug and play approach which was advertised by some of the conversion options. I have no evidence of how simple the conversion installations are, but have no reason to doubt their claims. However, in my case I purchased a lycoming 0-320 D1A from Vans and their firewall forward kit. You bolt the engine on the mount, wire and plumb per the plans. The plans are simple and the most straight forward of all the Vans dwgs. IMHO. There were a few minor wire routing and securing questions that my tech guy helped with. Otherwise, it couldn't have been simpler. It was one of the most satisfying parts of the building process. And I am a pure novice. I had an A&P AI check it out and he made only one suggestion. He also said "where did you get that exhaust?, it's a great set-up". Jack RV9A, ready to schedule DAR.
 
Tom Maxwell said:
Of course you guys driving the rockets with the big gas guzzling 540's in them don't care about money ;). So you guys should be leading the way and trying all of these new options so we po folks will have more data from which to make our decisions. Just kidding!
Common misperception. The IO-540 actually only guzzles more gas if the Go Lever is pushed all the way forward (not often). It would probably surprise most people to learn that the IO-540 is as fuel efficient as it's smaller cousins at typical cruise settings. However, if you want to go really fast, it will drink the well dry in no time.
 
f1rocket said:
I don't know any engine engineer that thinks gear reduction units are the best way to turn a prop. No, it's just a band-aide stuck on an engineering problem that otherwise, can't be fixed.

Maybe not for simplicity, however every liquid cooled aircraft engine from WWII, and all of the radials bigger than the R985 have PSRUs. HP=TxRPM/3300, more RPM, more power and at a certain point more better power to weight. I agree with you, but I wouldn't denograte them all as bandaid fixes. I still wouldn't buy anything with a G0-anything even if I could afford it.

IMO, I wouldn't consider a auto-conversion for any reason. As mentioned above, cost/benifit never seems to balance. However, for engines over 300-400hp there seems to be a place for custom built, automotive based engines such as the Donovan/KeithBlack/Falconer that are built for 700hp, but severily detuned to operate around 400hp continous. Think more like a marine engine than an auto engine. I still wouldn't do this for cost reasons, but only because I think 0-720s suck, and an MP-14 or 985 might not fit.
 
3 forced landings.

I wonder if the Subie guy you know is the same one I know that also had 3 forced landings. One on takeoff at my airport. One was on a road on the way to Oshkosh 2004. Fixed it on the road, took off on the road, and then flew to Oshkosh Airventure 2004. One was over an airport on the way home from Oshkosh as he was over the airport when the problem happened.

The story goes on my airport is that two more forced landings and he is an ACE.

Gary
CCB in SoCAL
RV-6 1,644 hours flying, O-320 (4,882 TT engine), Hartzell Prop

Scott DellAngelo said:
My $0.02.

SNIP

I know on very good source (someone who knows and flys with the guy) that one of the biggest Subie supporters has had multiple (yes multiple) forced landings, at least one of which was off field. Another was on takeoff. Don't email me asking who because if he isn't saying anything (i've never seen anything about it) then he probably doesn't want people to know so I won't be the one to spill it. I will say that the guy who told me had no reason to lie to me and seemed to know the details very well.

I respect the guys who try it, don't get me wrong, but no way was/is one going of the front of my RV. Instead I got a used Lyc that I am overhaulling myself and should be WELL below the cost of any other option and be freshly overhaulled.

Scott
#90598 Fuselage (making no progress with the current state of my shoulder :( )
:D
 
ok guys, now you're giving it away :)

on a more serious note, and all joking about being an ace aside, this is quite concerning. This is not a sport to test your luck in... you'll be disappointed how quickly it runs out.

PS. to reflect on one of Tom's posts -- on contrary, the pricing of soobie packages made this decision a total no brainer. I'm only afraid I would have been tempted to consider an alternative if it was 50-60% cheaper.. but with these numbers, it's really easy to make that decision.
 
New Technology Engine

The aircraft engines of today have been around since WW2. Some people use antique automobile engines. Some people use rotary engines ,noisy but high fuel flow and smooth. And some use higher tech auto engines.
After many dyno runs (nearly 5000) it becomes obvious what works and what doesn't. There are many requirements of a good aircraft engine. Stated below are some of them.
1. Smooth internal combustion engine. Smooth is a flat 4, flat 6, inline 6, vee 12 . Turbine engines (external combustion engines are too costly) are not used in light aircraft.
2. Low fuel consumption of an economical fuel.
3. Proven long life
Under 1. of above an inline 4 , V6 , V8 , doesn't make it. No matter whats done the engine doesn't make it. Anyone that has read an engineering manual can tell you. If some one tells you that they got it to work is lying to you. Rotary engines are very smooth but thier fuel consumption suffers.
Under 2. Because aircraft have to carry all the fuel to burn , a low fuel consumption means a lower gross weight and all the benefits of this. An economical fuel don't mean LL100 that sells for more than $4.00 a gallon in the United States. A maximum fuel flow that is low is good. (BSFC) brake specific fuel consumption is used. The units of measure are pounds of fuel per horsepower hour.
Under 3. Here the typical aircraft engine is the winner. But we can't sit on our back sides and say or do nothing.
So you can see that a usable aircraft power plant is not some thing available anywhere. The alternative to the old reliable may not be good.
Lee
 
Good Aircraft Engine

A modern and good aircraft engine would be the following:
Liquid cooled - Air cooled engines suffer from being too cool and to hot. Liquid cooling would maintain the temperature no matter if your climbing or desending. A good engine temperature to maintain is 180 - 200 degrees f .
A flat four. Naturaly perfect balance and fit in the existing airframes.
200 hp - This horsepower is what people are looking for and it would provide the desired cruise speeds, take off distances, and climb performance.
Engine would run on light oil. No. 1 or 2 diesel , JP4 , Biodiesel. This would make an ignition system totally unneeded . The fuel cost would be lower and the emmisions would also be lower.
4 cycle diesels are very heavy. A good long lived 2 cycle diesel has been in use for a very long time. The 2 cycle Detriot Diesel model 53. Supercharging is needed to start. At altitude the air becomes less dense (lower pressure) and a compresser is needed anyway. The two speed supercharger ( not turbocharger ) first apeared in WW2. So starting and flying at altitude would be easy.
With these thoughts in mind you could net an engine with the following specs:
200 hp at 2800 RPM Normalized to 20,000 feet.
Engine weight that is very comparable to an IO360.
Engine life around 4000 hours.
An electric preheater would make the engine usable in any climate.
This sounds like a dream but very easy and do able.
Lee
 
leeschaumberg said:
A modern and good aircraft engine would be the following:
Liquid cooled - Air cooled engines suffer from being too cool and to hot. Liquid cooling would maintain the temperature no matter if your climbing or desending. A good engine temperature to maintain is 180 - 200 degrees f .
A flat four. Naturaly perfect balance and fit in the existing airframes.
200 hp - This horsepower is what people are looking for and it would provide the desired cruise speeds, take off distances, and climb performance.
Engine would run on light oil. No. 1 or 2 diesel , JP4 , Biodiesel. This would make an ignition system totally unneeded . The fuel cost would be lower and the emmisions would also be lower.
4 cycle diesels are very heavy. A good long lived 2 cycle diesel has been in use for a very long time. The 2 cycle Detriot Diesel model 53. Supercharging is needed to start. At altitude the air becomes less dense (lower pressure) and a compresser is needed anyway. The two speed supercharger ( not turbocharger ) first apeared in WW2. So starting and flying at altitude would be easy.
With these thoughts in mind you could net an engine with the following specs:
200 hp at 2800 RPM Normalized to 20,000 feet.
Engine weight that is very comparable to an IO360.
Engine life around 4000 hours.
An electric preheater would make the engine usable in any climate.
This sounds like a dream but very easy and do able.
Lee


Sounds a lot like what DeltaHawk is trying to put together.

PJ
 
Delta Hawk Engines

Delta Hawk Engine is trying to make a non smoth engine smooth and reinventing the wheel. For enough money , some people will say or do any thing.
Lee
 
xm15e said:
... HP=TxRPM/3300,.../
I hate to nit pick but since none of the other arguments will truly sway anyone away from his opinions, I thought I would just correct this formula.
One horsepower is a work rate of 33,000 ft-lb/minute.
If we have a torque of one ft-lb and we calculate the work done by that in one revolution of the crankshaft, then we will have done 2pi ft-lbs of work.
In order to determine how many rpm we need to get one horsepower out of that, we need to divide 33,000 by 2pi.
This gives us ~5252rpm.

The formula should be HP=t*RPM/5252. The neat consequence of this formula is that torque and horsepower are always numerically identical at 5252rpm.

Sorry again and no offense intended.
-Mike
 
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just for kicks, let's flip this discussion on it's ear.

the NEWEST production (notice i said "production") engine type -- of any kind -- is over 60 years old. for those that are counting, that would be the axial compression internal combustion engine, a.k.a. the gas turbine.

we're talking about "core engine design" ... not peripherals like FADEC, etc.

the piston engine hasn't changed in over 100 years. improved, yes. but the fundamental design is exactly the same.

ask yourself why there are no turbine cars cruising the highways. simple, light, long-life, etc. what happend? turbine concept cars were all the rage in the 50's....certainly the advances in technology should be able to make a turbine car an affordable reality today.

why not? because it doesn't fit the mission. in stop & go traffic, a bicycle can out-accelerate a turbine car up to 10mph. (we're not talking about jet trucks at airshows). you'd also be riding the brakes up to 60mph since turbines idle at 80% power. not to mention getting about 2mpg and an exhaust the size of a sewer pipe.

i am all for experimental installations, but let's face it -- 99.99% of builders are not experimenters. An RV is the FARTHEST thing from an experimental plane you can get...and the success of Van's is a direct result of his "no experimental" philosophy

..the main issue here is suitability, safety and longevity.

if you're reading this thread b/c you want to learn about engines in airplanes, there are several posts in this thread which make very clear, concise arguments for the following wisdom:

form follows function.

car engines are for cars, truck engines are for trucks, boat engines are for boats......and airplane engines are for airplanes.

sounds obvious, but the reality is quite compelling. the dominant airplane engine design for light aircraft has EVOLVED into what works best.

there is NOTHING that hasn't been tried in airplanes over the past 75 years. turbines, diesels, car engines, steam, rotary....even nuke....you name it

the first diesel aircraft engine flew in 1930!! the DeltaHawk may be "new" but at least it was designed PURELY as an airplane engine

sometimes a design reaches a perfect point.....the B52 bomber is a perfect example of something that got it right....sure it has new engines and avionics, but it will still be flying at 100 years old.

we still can't fly like birds, but when was the last time you saw a 400 ton pelican doing 600mph at 35000 feet?

the concorde was a wonderful airplane but an utter failure as an airLINER....it simply did not fit the mission

an F18 is a great plane....but not exactly a "day-VFR go get a burger" kind of ride

canards are "more perfect" airframes....yet they are not nearly as user-friendly or as flexible as conventional planes.

the bottom line is that engines designed for other purposes are AT BEST a serious compromise in an airplane installation.

not because the "technology" is better or worse, but because the design is entirely unsuited to the mission it is being asked to perform.

the subaru engine has been fairly successful because it happens to be relatively close to an aircraft-type design. durability and reliability in airplane mission are the unknowns. the eggenfellner installation has many good points....it remains for accumulation of fleet hours to work out the inevitable kinks and weaknesses in a complex installation.

if you took a clean sheet of paper and designed an engine for an airplane, you'd end up with an airplane engine...not a car engine. it might be a diesel or a turbine or a gasoline engine...but it would be an airplane engine for airplane missions.

if you choose to pursue a conversion engine installation, be very realistic about sacrificing one or more of the qualities you are looking for in an airplane engine (longevity, reliability, cost, weight, simplicity, efficiency, ease of maintenance, field support, durability, etc.).
 
External Combustion Engine

Sorry to correct you but a turbine engine is an external combustion engine. An internal combustion engine uses pistons. Please see any book on engines to confirm this fact.
Lee
 
Inernal/external combustion?

Sorry to correct you Lee, but a gas turbine as it applies to aviation is an internal combustion engine. A steam engine is an external combustion engine. There are external combustion turbines, but they'd be driven by steam.

Reference this:

"The Basics
The purpose of a gasoline car engine is to convert gasoline into motion so that your car can move. Currently the easiest way to create motion from gasoline is to burn the gasoline inside an engine. Therefore, a car engine is an internal combustion engine -- combustion takes place internally. Two things to note:

There are different kinds of internal combustion engines. Diesel engines are one form and gas turbine engines are another. See also the articles on Hemi engines, rotary engines and two-stroke engines. Each has its own advantages and disadvantages.

There is such a thing as an external combustion engine. A steam engine in old-fashioned trains and steam boats is the best example of an external combustion engine. The fuel (coal, wood, oil, whatever) in a steam engine burns outside the engine to create steam, and the steam creates motion inside the engine. Internal combustion is a lot more efficient (takes less fuel per mile) than external combustion, plus an internal combustion engine is a lot smaller than an equivalent external combustion engine. This explains why we don't see any cars from Ford and GM using steam engines."

Quoted off of Howstuffworks.com

Tobin
 
leeschaumberg said:
Sorry to correct you but a turbine engine is an external combustion engine. An internal combustion engine uses pistons. Please see any book on engines to confirm this fact.
Lee
Actually, Mr. Shaumberg, the Brayton cycle engine as used in aircraft operations IS an internal combustion engine, operating in an open cycle. There is no restriction on internal combustion engines that they be constructed using pistons.
Gas turbines operated in a CLOSED cycle where the working fluid is continuously recirculated is not an I.C.E. because the fluid cannot support continuous combustion and the heat energy needs to be added externally to the cycle.

-Mike
 
I don't see what all the fuss is about. What is so wrong with Lycomings other than the ridiculously high cost (which is mostly a consequence of simple supply/demand issues)? These things run great and last and last. They can be brought into the modern age by simply using a more modern ignition or FADEC. I just don't see what is so bad about them.
 
szicree said:
I don't see what all the fuss is about. What is so wrong with Lycomings other than the ridiculously high cost (which is mostly a consequence of simple supply/demand issues)? These things run great and last and last. They can be brought into the modern age by simply using a more modern ignition or FADEC. I just don't see what is so bad about them.

Biggest changes I'd like to see would be liquid cooling (no worry about shock cooling, reduces need for complex engine management) and less reliance on 100LL (I'm partial to diesel/Jet-A, but anything's better than 100LL).

PJ
 
As for water cooling, it adds weight and complexity, and lots of new failure points. Think of how many times you've seen cars on the side of the road steaming. As for the fuel, use lower compression pistons and you can run mogas. It just seems that the old Lycoming can be adapted to do just fine with a whole lot less work than trying to adapt an auto engine to an airplane.
 
szicree said:
As for water cooling, it adds weight and complexity, and lots of new failure points. Think of how many times you've seen cars on the side of the road steaming. As for the fuel, use lower compression pistons and you can run mogas. It just seems that the old Lycoming can be adapted to do just fine with a whole lot less work than trying to adapt an auto engine to an airplane.

Not all that often. Assuming the vehicle is maintained it shouldn't be an issue, although I agree that there are trade-offs.

I'll turn it around on you and ask you how many people you know who've had to replace cylinders on their car? Now ask that same question of pilots you know.

PJ
 
Internal versus External Combustion

mlw450802 said:
Actually, Mr. Shaumberg, the Brayton cycle engine as used in aircraft operations IS an internal combustion engine, operating in an open cycle. There is no restriction on internal combustion engines that they be constructed using pistons.
Gas turbines operated in a CLOSED cycle where the working fluid is continuously recirculated is not an I.C.E. because the fluid cannot support continuous combustion and the heat energy needs to be added externally to the cycle.

-Mike
All of the companies that I worked for (5 companies) said the turbine was an external combustion engine. The Milwaukee School of Engineering said a turbine is an external combustion engine. You say it's not! Hmmmmm I wonder who I should believe?
Lee
 
Air vesus Water cooling

szicree said:
As for water cooling, it adds weight and complexity, and lots of new failure points. Think of how many times you've seen cars on the side of the road steaming. As for the fuel, use lower compression pistons and you can run mogas. It just seems that the old Lycoming can be adapted to do just fine with a whole lot less work than trying to adapt an auto engine to an airplane.
Would you please forget automobile engines.
Water cooled engines are a big IMPROVMENT over air cooled engines. Many people still think air cooling is cool. The Wright Bros. if still alive wouldn't think so. Lycoming and other aircraft engine manufacturers have water cooled engines in thier test labs. They will introduce them when they want to. You compare water cooled engines to a jerk (Not You) driving a car that doesn't believe in proper maintainence. Lawn mowers still use air cooled engines because thier cheaper to manufacture. I know , I worked for Briggs and Stratton.
Lee
 
On cars I've owned I've had: brand new water pump fail, brand new thermostat fail, brand new temp sending unit fail, debris rupture radiator core. I'm sure there have been others. I know water cooled is the way to go for cars, but perhaps not for all things. Motorcycles, for example, often run air cooled engines. I have one of each type, and can tell you that the water cooled engine is much heavier. I guess I'm just from the "if it ain't broke, don't fix it" school, and I can't see what's so broke about our current motors.

On the debate about internal vs. external, all resources I've checked define an internal combustion engine as any engine in which the expansion of combustion gasses DIRECTLY drive the engine. This would, of course, include both piston and turbine types, and exclude the good old steam engine.

Incidently, I have some trouble believing that the Milwaukee School of Engineering speaks as a single entity on any subject.
 
More internal/external combustion arguement

Not sure why I'm argueing this silly point still, but Lee, how about this one:

Dictionary

(Click to enlarge)
gas turbine
turbojet engine
(Precision Graphics)
gas turbine
n.
An internal-combustion engine consisting essentially of an air compressor, combustion chamber, and turbine wheel that is turned by the expanding products of combustion.

Like Szicree, every website I checked out supports this. Besides, where'd you get the idea that IC must have pistons? Internal means internal. The pistons only compress air, just like the compressor blades in the gas turbine.

On another note Lee, I agree with you 100% on your liquid cooling post. Properly maintained, the liquid cooling system is no more prone to breakdown than our current setup on Lycs for the oilr cooler/pumps/hoses.

Tobin
(In an arguementative mood, Sunday night and bored I guess, though I did log a 1.2hr this afternoon in my -7:) )
 
leeschaumberg said:
All of the companies that I worked for (5 companies) said the turbine was an external combustion engine. The Milwaukee School of Engineering said a turbine is an external combustion engine. You say it's not! Hmmmmm I wonder who I should believe?
Lee
Believe whomever you want but it is still a fact that SOME turbines are internal combustion engines and SOME are external combustion engines. The determining factor is whether the heat added to the working fluid is added internal to the cycle or external to the cycle. It is as simple as that.
In all jet aircraft and turboprops, the combustion cannister is inside the engine, using the air flowing through it as the working fluid.
It is entirely likely that all the companies you worked for were building turbines that were externally heated for their operation in which case they would have been correct about "their" turbines being external combustion engines. It is one of those life experiences that unfortunately enforces a myopic view of the world. It has happened to most of us at one time or another.

Broadening the discussion slightly, a piston engine is not necessarily an I.C.E. either. Sterling cycle engines are routinely constructed using pistons in their design but the working fluid is in a closed cycle and the heat must be added externally. Another example that we are all familiar with is the old fashioned steam driven locomotive. It is an externally heated combustion engine.
Changing the fuel to a combustible gas and adding a spark ignition such that the combustion takes place in the cylinder could convert the same engine to an internal combustion engine.

The only difference is where the combustion takes place and a necessary and sufficient part of an I.C.E. is that the WORKING FLUID take part in the combustion process. That's where the 'Internal' adjective comes from. It describes whether the combustion, in the heat engine being described, occurs internally within the working fluid or externally to it.

Again, believe whomever you want but quoting words from the Cold War, "trust but verify"

-Mike
 
I.C.E. per Brittanica

Encyclopaedia Brittannica Article.

Internal combustion Engines

"...any engine in which a fuel-air mixture is burned in the engine proper so that the hot gaseous products of combustion act directly on the surface of its moving parts, such as that of a piston or turbine rotor blade. Internal-combustion engines are the most widely used of all present-day power-generating systems. They include gasoline engines, diesel engines, gas-turbine?

-Mike
 
ICE versus ECE

To all readers , Mike , and Tobin

I wish to apologize to all the readers of this thread.
I have been incorrectly made to believe that all turbines were external combustion engines. In reality all turbines that are driven by an external process like the formation of steam are external combustion engines. Aircraft turbines generate heat from the burning of a fuel within thier structure. A fuel is injected into the combustion chamber and stays burning until a (flame out) occurs. This hot air expanding turns the turbine wheel or wheels.
Over the years a school and many manufacting companies have helped me to believe that all turbines are external combustion engines. I now know why. Everybody from my part of the country (southeast wisconsin) only builds piston engines! Back when I thought it was dumb. I was right.
I do not have a PHD in engineering so I didn't know. Word to the wise ( assume nothing ).
Again I apologize
Lee
 
Tak it easy

I like the discussion but I think you guys are getting to hung up on words. "internal vs External"

Both pistions and turbines do the same thing.

suck, squeeze, bang, and blow.

:)
 
leeschaumberg said:
To all readers , Mike , and Tobin

I wish to apologize to all the readers of this thread.
I have been incorrectly made to believe that all turbines were external combustion engines. In reality all turbines that are driven by an external process like the formation of steam are external combustion engines. Aircraft turbines generate heat from the burning of a fuel within thier structure. A fuel is injected into the combustion chamber and stays burning until a (flame out) occurs. This hot air expanding turns the turbine wheel or wheels.
Over the years a school and many manufacting companies have helped me to believe that all turbines are external combustion engines. I now know why. Everybody from my part of the country (southeast wisconsin) only builds piston engines! Back when I thought it was dumb. I was right.
I do not have a PHD in engineering so I didn't know. Word to the wise ( assume nothing ).
Again I apologize
Lee
Jeez Lee!
No apology necessary! As I said in one of my posts, I have incorrectly and even sometimes stubbornly held to an opinion only to find later that my experiences were not as all-encompassing as I had believed. You are a bigger person that I may have been here if the tables were turned. This just happened to be an area where my education was specialized and the definitions were easily recalled to me. I am sure there will be many opportunities for you to educate me with your experiences and I just hope I am smart enough to realize it when it happens.
-Mike
 
mlw450802 said:
Jeez Lee!
No apology necessary! As I said in one of my posts, I have incorrectly and even sometimes stubbornly held to an opinion only to find later that my experiences were not as all-encompassing as I had believed. You are a bigger person that I may have been here if the tables were turned. This just happened to be an area where my education was specialized and the definitions were easily recalled to me. I am sure there will be many opportunities for you to educate me with your experiences and I just hope I am smart enough to realize it when it happens.
-Mike

Ditto

Steve Zicree
 
Reply to Traditional vs Alternative Powerplant

To all that wrote
Thank You all. I might be dumb but not stupid! I do have much dyno experiance using natural gas(almost 120 octane) , propane (low in octane) and hydrogen (almost 120 octane). Now that we have carbon fibre for storage I think the later is the winner. Now all I need is a flyable RV8 not a RV8A.
Lee
 
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wow! i'm gone for a day and look what happens. :D

(lee: don't feel bad....we all make mistakes. i know i've made more than my fair share of doozies in various emails over the years.)

i've been fortunate to be closer than most folks to the birth of an aircraft engine from clean-sheet design. lots of dyno time and burnt engines. the only sure thing is that all bets are off when you move from the dyno to the test rig. even the dyno is a big unknown the first time around.

people like to bash lycosaurs, but this is a bum rap. the statisitcal reality is the lyco 320/360 and the TCM 470 are the most reliable piston engines ever built. ever. that includes the millions of small-block chevy/ford engines, truck diesels, etc.

is there room for a new engine design in GA? absolutely.

you don't have to look very far to see that a good "design" doesn't guarantee success....the bigger Lyco and TCM engines are far less reliable even though they are DIRECT derivatives of the smaller engines.

being fairly privvy to what's happening in the aircraft engine world, i can say with relatively high confidence the following:
-- engine design is extremely complex & expensive....if it was easy & cheap everyone would do it.
-- trivia: GM and Ford are spending $1billion to jointly develop a SINGLE new transmission for light trucks...that's how bad it is
-- $20k for an engine is a BARgain .... a 20hp lawn-mower diesel costs $5k
-- there's far less profit than you think in a Superior or ECI engine.
-- shock-cooling issues are 99% pilot error
-- slow revving engines last longer than fast revving engines
-- the flat aircooled design is closest thing you'll find to the perfect piston engine for light aviation
-- the Lyco 320/360 and TCM 470 are statisitcally the most reliable piston engines ever produced
-- lycomings, radials, etc. ARE liquid cooled...it's called fuel...no need for heavy radiators, etc.
-- the Lyco/TCM conspiracy to keep new technology on the shelf is bogus...the cost of development to get through FAA certification is horrendous with no guarantee of success....they own the market already
-- the TCM gap project is a crime....that money should've gone to one of the startups like DeltaHawk
-- automotive designs will never succeed as aircraft engines...e.g. the Bombardier engine is far too complex even though it was designed as a pure aircraft engine.....Orenda tried it....lost $40million
-- subie conversions will do better than rotaries over the long haul
-- only 1 diesel has potential to succeed commercially...DeltaHawk
-- no turbine will succeed commercially below 350hp due to BSFC
-- survey of importance in ACTUAL engine purchase decisions: reliability, economy, price, latest technology

FUN FACTS
form follows function: top fuel dragster
type V8
horespower [email protected],000hp PER cylinder!!
torque 7000ftlb@6000rpm
weight 550lbs
fuel flow 180gpm...that's 10,800gph...or 1000x lycoming
cost $75,000
TBO 10 seconds (2 runs)
 
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Nice debate,

Nice write up/summary from Ship,

Question for "Ship":
i've been fortunate to be closer than most folks to the birth of an aircraft engine from clean-sheet design.
Ship, could you shed more light on your statement?
 
f1rocket said:
Oh boy, where do I start.

Automobile engines may be of a higher technical level than a Lycoming, but they are NOT superior when it comes to driving an airplane through the sky. Take a look at the main crank bearings and the engine block of a Subaru and compare them to the Lyc. When you are swinging the weight of the prop out front, it requires some hefty support. Lyc's also deliver peak power at low RPM, while the Subies need to scream along at much high RPM to deliver peak horsepower, hence the gear reduction units. I contend that automobile engines are very poor airplane engines because they need to be jerryrigged to make them work.

I fly a Sube and rebuilt the engine myself being a racecar engine builder by profession. The engineering, metallurgy, choice of materials, machining and balance of the Sube is far superior to anything seen in a Lyc. I have never heard of a bottom end failure on the EJ series Subes. There is no doubt that they can take much higher continuous stress. This was proven by their wide open run : http://www.subaru-global.com/about/history/1989-001.html#subhead-001

Anyone who thinks that modern auto engines are not capable of spinning at 4500 rpm all day, all month, all year long is simply ill-informed. I built and road raced Japanese engined cars for 13 years making over 5 times their naturally aspirated stock power and running them 2500 rpm over the stock redline. Not one ever suffered a catastophic failure.

The benefit they have is that they are cheap because they are mass produced. Can't beat that. They also have great reliability when used for their intended and designed use. Start sticking them in airplanes and you are bringing along a whole additional set of engineering problems to be solved. I don't know any engine engineer that thinks gear reduction units are the best way to turn a prop. No, it's just a band-aide stuck on an engineering problem that otherwise, can't be fixed.

What is this? Every Pratt, Wright, Allison, and Merlin had a reduction gear. You call that a band-aid?

The whole 100LL thing has become the enabling battle cry of the alternate engine groupies. Unfortunately, it doesn't hold water. No one is going to wake up one moring to find that hundreds of thousands of engines that use the product suddenly are silent because no one is making it any longer. I don't doubt that there will be a transition to other fuels in the long run. That's probably why the diesel engine is looking like a viable engine alternative. But you and I will be able to buy 100LL for many, many years to come. Now the price of that gallon of 100LL may be another issue.

My Sube runs on 100LL just fine or 91 octane if I choose.

Finally, the reason I fly a homebuilt and not a Cessna 150 is because I can upgrade my Lycosaur with electronic ignition, FADEC, etc and get the best of both worlds----newer features and capabilities with proven reliability.

Proven? Every 24 hours, there are more high speed hours put on cars running in Germany alone, than all the Lycoming engines ever built have accumulated in the last decade. For every hour that Lycs have, cars have accumulated millions of hours. You don't think Lycs break? Better brush up on those accident reports. There are plenty of fatals caused by catastrophic failures and don't forget the class action suits brought against Lyc and their turbocharged 540s where dozens blew up or went only a fraction of the time to TBO. Let's not forget the recent judgement against Lyc for the crank problems and all the other problems these "proven designs" have suffered in the last 5-6 years. This is a joke when you are paying $30,00+.

Some might find this interesting: http://www.sdsefi.com/air7.html
 
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