After reading this post I thought I'd throw in my thoughts on using a Subaru engine. My extended family drives and has driven Subarus exclusively for well over a decade. I'm the only family member who doesn't since Subaru didn't make a truck when I was in the market.
Anyway, my point is this...although these cars do have small things that go wrong with them from time to time, I cannot remember one instance when my family has EVER had ANY trouble with a Subaru engine. These engines have never missed a beat and keep humming right along no matter what. Simple and routine maintenance is all that these engines need.
Bottom line...I would feel far more comfortable flying behind Subaru power than Lyc/Cont/Franklin power ANY day of the week.
I know this isn't aircraft application experience, but my wife had a 1993 Subaru Legacy wagon with the 2.2 liter non-turbo engine. It had 302,000 trouble free miles on the engine when she hit a deer on a freeway. Allstate said it was totaled because of the high mileage, but it still ran perfectly, even the clutch was original! I put in a new timing belt at 170,000 miles (it was still working OK, just preventative maintenance), but that was the only thing I replaced other than spark plugs. It never missed a beat and only used about 1/2 quart of oil between changes. It used that much oil since it was new, it never got any worse. If I could get a Subaru light enough for my Minimax, I would sell my Zenoah 2 stroke today. Subaru makes great engines.
I'm considering it for my kit and looking for input. Their website of course touts it as the engine that will revolutionize homebuilts, etc.
One concern I have with auto conversions (in general) vs. the Lycomings is the higher RPM's thru a reduction unit for the correct prop RPM's. Even at cruise, compared to what the RPM's would be in an auto, they would be significantly higher and over time seems that it would wear the engine out faster?
G'Day from OZ,
Hey DAVE for PRESIDENT You said it all man!
In the ideals of Douglas Adams, 'We need to get all these legal types, and their followers on the 'B'-ARC! :angry:
As for SUBI motors (and cars) I've had three and I couldn't go back to anything else which brings me to; FENANDO
"The more I research the Soob the more I am convinced. Even the auto shops I have contacted locally rave about the EG33. AND - it's already sitting in the garage. Kinda hard to give that up." OMG, I hope you only have a motor there and are not intending to carry out surgury on an SVX :wail:
I've got one of these treasures, and to anyone who has not driven one (Captain John?) you owe it to yourself to research this vehicle and if possible have a drive :ban:
You will find it hard to enjoy driving anything else ever again. :
HeyZmanif you get a Soob in your MiniMax, how much do you want for your G-50?
Any engine, operating within its design parameters, should not really be seriously affected by the rpm of operation. One way to look at it is from the standpoint of fricition. You genrally have two types - static and dynamic. Static friction comes into play for parts that are not moving relative to each other but just starting their motion. Static friction is much higher than dynamic (example: car driving normally (static) versus a car skidding (dynamic)) and thus engines see most of thier wear from cold starts, not from running.
Following this reasoning, the faster the rpm of an engine, the lower the fricition forces. Yes, this is all relative and the actual decrease is small in the operating range of a conventional engine, but the point is, from a fricitional standpoint, the high rpm will have little effect on the engine's useful life.
For engine protection during long periods of inactivity and from cold starts, I highly recommend using the Microlon additive (see www.microlon.com). I usually don't believe in additives but a few years back I put this into my two place Grumman and the difference was quite amazing. It is FAA certified (for those with certified airplanes) and so just about anyone can use it to good benefit.
The major problem that I see in the industry is the lack of good design practices in designing the reduction drive that we need to put on these engines in order for them to work well in our airplanes. There are quite a few out there but hardly any would I trust enough to actually fly behind. Looking over the choices, most are quite attractive, using a variety of professional methods of manufacturing. The probem though is that virtually none of them have any serious engineering behind them. You only need to read some of the advertising web sites to see the level of BS that they try to pass on as relevant knowlege. This is especially telling when you read their discussion of torsional resonance. Most don't even seem to know what it is, let alone how to account for it in the design.
In short, it is very important to be extremely careful in making your selelction of the drive as this is the weak link in the chain, not the engine.
Sorry that I haven't been checking in of late. It seems that this thread has gained a bit of momentum!
Pecosbill, That Crossflow engine looks GREAT! The company really holds it in high regard with a $30,000 price tag! For that kind of bling, I would be more likely to get the Soob.
Speaking of which, Pylon... The 3.0 Liter Soob 190hp that Egg is developing now seems very interesting! Here in New England I need normally aspirated sea level horsepower in an RV. That 6 cylinder would seem to fill the bill!
How hard do you think it would be to whip up my own 3.0 liter Soob design using an NSI gear redux and off the shelf parts?
From all that I've seen regarding the Subaru engine, I think it makes an excellent aircraft powerplant. The only remotely negative thing that I've heard is that it still takes Lycosurus pilots a while to get used to the higher rpms but otherwise it seems to be an excellent option for many of us.
Doing your own is certainly an option, especially if you get an engine from one of the Japanese used engine importers rather than a wrecking yard. As I hear the story, the Japanese emission requirements are so strict that every car owner has to get a new engine at about 25k to 30k miles in order to meet the extreme standards. As such, many of the imported engines have extremely low miles - barely broken in. The only drawback to these engines is that some of the US parts for these engines may not be interchangeable with the Japanese ones. However, since this usually impacts only the emission control components, it wouldn't be a big deal for aircraft applications. Usually you can pick these engines up for about $4,000, give or take a bit.
Regarding the reduction drive - my personal opinion is that I would never get in an airplane with anything from NSI. While their products look impressive, there is little or no actual engineering behind them. Between that and the rather less than upfront business dealings the company is continually involved in, I'd recommend looking elsewhere.
Looking back on the site I see people talking about 3.0 litre Subi's and just realised that there are two six cylinder motors available. There's actually three, but their first one was only 2.7 litre (ER-27), although it is only a single cam (per head) which could make it a bit lighter.
The popular six at the moment is the 3.3 litre (EJ-33) from the Subaru SVX, built between '92 and '97.
The current engine used in the OUTBACK (as we call it here in OZ) is only 3.0 litre, but still 24 valve, quad cam and injected, possibly called the H6-30(?)
However, this is supposed to be a totally new designed engine having undergone a weight loss program and been compacted to more easily fit into previously four cylinder locations
I'm still trying to track down more info, but I do know they are expensive, being the current model and all.
Jan makes his own (actually has them made for him).. NSI's I wouldnt touch... There are several more Soob PSRU maker out there, but mostly 4 cylinder ones.. (Stratus, NW Aero) But Crossflow has a 6 cyl and a PSRU also...
The H6 is the 3.0 ... with a turbo 320hp(?) supposed comming out in 2005
Jan will talk to you, but dont expect much beyond marketing. Most tech questions get met with 'its a secret'. Anytime you question his motors you'll get the answer 'you need a Lycoming 'cuase your just not ready for the most modern airplane engine in the world'... Bah:angry:
Anyway, try the Yahoo Groups - Subaruaircraft (Jan's), E-SubieForum (pro-NSI), Vansairforce (mostly pro-Jan), Airsoob, and Flysoob - for more info..
Several folks have emailed me asking my opinion of the Eggenfellner reduction drive so I thought I'd answer here.
I have not actually done any specific analysis of this drive however seeing it installed on several aircraft, what I can say is that it certainly looks good. The trouble is that without a closer investigation, at times looks can be deceiving.
Looking at their web site, the description and methodology behind the design looks quite good. I especially like the fact that the most stressed part of the case is machined from billet rather than cast. I also like that they're using their own gears rather than trying to use something from an autotmotive source.
The only concern I came up with is in relation to their page that discusses torsional vibration. I came across this page at their site some time ago although this morning I couldn't find it. Reading through the material it was pretty clear that the author may have heard of the subject but really was not well versed in the subject, its effects, nor its solution.
However, given their good history, and the seemingly good quality of their components, I would say that I would seriously consider taking a closer look at their products if I was in the market for a Subaru installation.
My first notion, as I read this thread, is that the reason I am building an airplane in my garage is because I really love to fly airplanes. Within that are the practical, technical, economic, and even political issues to deal with, but the baseline I begin with is that I need an airplane that I can fly for what I can afford to pay. It may have been a while for some of you, and the shock effect may have worn off a bit, but when somebody tells me that they have a nice low-time, no prop strike, 100 hp engine -of any sort- and looks me in the eye and without blinking tells me he wants $9,000 or $12,000 for it, it surprises me. I get a little dizzy!
I am a carpenter (Contractor). I know very little about engines. My ex-wife knows more about engines than me. (She also knows more about engines than I!) If I cannot fix it with wood and glue and nails and screws it doesn't get fixed, (imagine how delighted I was to learn that automobile manufacturers print SERVICE MANUALS) so naturally I am attracted to the Subaru option. This is actually new to me. I just learned about this, and frankly I am pleased and relieved that this option is available. I understand the existing AC engines are good solid proven designs, and that is the way it is, but i am delighted to find out that I am not alone when I say that, for what they cost, I am completely unimpressed.
I went to the Subaru dealership the other day because I don't have any realistic sources for this kind of information myself, and asked about factory rebuilt parts and engines. The parts guy didn't know what an EA81 was, but he had an injected 1.8L engine on his books. You can actually buy a factory rebuilt block (lower half) for not too much scratch, and buy new heads and injectors and distributor,etc. etc., and piece together the whole thing for somewhat less than I thought. Maybe less than $3500 for a unit that you could drop into a car and drive.
Is that what we are talking about here? Will a stock engine with a few special parts and a reduction drive need much more modification to bolt onto an airframe and fly away? If that is a reality for less than $6-7,000 then I'm all over it. Somebody write the book and I'll buy it, read it and write notes in all the margins! I just don't see the value in a 60 year old engine that is loud, uses special fuels and juices, vibrates so much that it's bolts fall out, fatigues the pilot, and needs a $10,000 overhaul after a few years of regular use. Where can I get more specifics about actually getting one of these things into my airplane? Do I need to pay an engineer in California to do some secret operation that I could do in my garage for half the price? and does it have to take me three years of trial and error to get it right? Has anybody written any specific instructions to do so? Please tell me.
Honestly, one of the things that has turned me away from homebuilding over the years is that many of the folks I have spoken/worked with seem to be very interested in finding the perfect process, material, design, or engine, and don't seem to be very interested in producing the product and flying it. It may be that it is just not that simple to teach yourself physical production assembly techniques, bla bla, or it may be that there is a limit to the usefulness of perfectionism. Not that attention to detail is not very important, but has anybody come up with a plan? I'd buy it it they have. The club rate on a 172 here is $97 an hour! That's what I would want too, but c'mon!
Any help? Comments? Anything else?
The longing for affordable power is common to all of us. We may have different ideas of what's affordable, but I think that in general, we all hope to find the ideal engine for a price that doesn't make us feel like we're buying another house. But before you go down that path, it is important to step back and take a close and detailed look at what it's going to take to install that "less expensive" option.
It is true that you can most likely build up a new engine fairly inexpensively, however another option would be to get a complete engine from one of the Japaneese engine importers. Most of these engines have very few miles on them (about 30k) as they are removed from the cars due to extremely strict Japanese emission regulations, not because of accident. Many powerplants that are sold as auto engine conversions for our industry, come from these importers.
And it is possible to take one of these stock engines, add what you need for flying, and bolt it in your airplane. However, when you do so, don't expect exactly stellar performance. This is for two reasons. First, airplane engines need max torque at the rpm range the engine is expected to operate. The cam geometry that is designed for the road however may not have the type of profile needed by the airplane. Yes, the reduction drive does allow one to maximize the torque output of a given engine but installing the right cam will help dramatically.
Second, many of the sensors that cars use today often don't tend to work as well when installed in a tight cowl. I've known several individuals who have spent more time on optimizing their sensor positioning than on the rest of the engine installation.
So, translating all this into dollars, let's say you really can get a basic "long block" for about $3,500. By the time you add all the accessories including the fuel injection system (or carburation), the ignition system, exhaust manifold, sensors, alternator, and whatever else, you probably better figure a price around $5,000, maybe a a bit more.
Since the Subaru has a relatively small displacement, it needs rpm to generate the power. Props however need to spin slower, so now you have to add a reduction drive. Off-the-shelf reduction drive units vary somewhat in price, but for the sake of argument, I'd guess this might set you back another $3,500, give or take a bit.
Ok, so now you've spent $8,500, but it's still sitting on your bench. Now you have to install it. Assuming all goes well with the fabrication of the installation components (which of course cost some more, especially since they will most likely be custom parts), you still have to make all this work under a cowl. That in itself can be quite a job.
Also, since most cowls that you can readily get information about are configured for the claassic airplane engines, your auto conversion will most likely be a custom job also (translated - time consuming). Here you trade off your time versus the conveniance of buying an existing cowl, or at least working with a conventional cowl design.
Adding all this up, the trade-off is the time required to make all this work versus the cost of buying a more convetional (and quite overpriced) engine which of course is designed for the job.
Can it be done for less? Most likely yes. It just depends on how good you are at finding deals. But be carelful - as in any market, one does tend to get what one pays for. Being that an angine is a rather critical part of the airplane, it might be prudent to spend a bit more.
So, how to go about this. The first step probably is for you to go the the EAA book store (or most other aviation book stores) and look around for books on this subject. Tony Bingelis has several books that were written especially for those of us who are looking for alternative power solutions. Also talk to others in your area, go to the local airports, and get as much information as you can from those who have been there. Hands on experience generates the most valuable advice. Also, there's no better explanation than being able to actually look under someone else's cowl. Good luck.
Good answer. Thanks.
What you have outlined there is a $10,000 project in the engine alone. That is actually not too bad, as afordability goes. A new certified engine can cost quite a bit more than that. That might be the overhaul cost of some mid size engines. I don't know, I have never paid for an overhaul. Looking upwind at it like this is no fun, but it still beats the cost of a certified ANYTHING. And the prospect of getting what you want rather than what is available is appealing. What I needed was, and is, a notion of what to look for. Most searches are best started this way. You have been very helpful. Thankyou.
Wow! these are some very interesting threads, I'm actually the guy that designed the little radiators Jan was using until our company went out of business.
He surely is a forward thinker and has contributed more than he knows in advancing the alternative engine useage with the complete firewall forward package. I agree with Archie on just about everything but need to interject my 2 cents as far as letting the FAA off the hook for the lack of advancement in powerplants. The process of achieving PMA (part manufacturing approval) is flawed and I have to assume that a great deal of resistance to change stems from the lengthy qualification process and all the hoop jumping associated with it. Lycoming and Continental have a good product, it sells and they make money on it.
Lets consider what they would have to go through to certify a new design and then put ourselves in their shoes, a great deal of that 27 grand they get for these engines is an amortized amount for achieving and keeping a PMA they achieved some 40 years ago for these, but what would it cost today.
It looks like the FAA is realizing this and the new regs for the Sport/Recreational categories seem to prove it...the future of aviation is in the hands of the private individual, the forward thinkers, not only the Ansari prize winners but as well, the folks willing to bolt a Mazda or Subaru engine on a machine and take it into the air. Watch everyone belly up to the bar when they are fitted with the redundancy and safety of magnetos.
We could blame the legal system or insurance industry but that's easy, I would hope someday the EAA will lobby Washington with some fire in thier belly for reform in this area...there are alot of pilot lawyers in the air as well.
As for PMA there are companies (Pacific Cooler) that think achieving PMA is just fudging some data and submitting it properly. This as well is another thing that frustrates the FAA and makes the process that much more cumbersome.
Sorry for not keeping up with the discussion, but regarding Crossflow, I would strongly recommend against them. Check this out from a close frined's personal experience:
Engine was delivered with the following parts missing:
Exhaust pipe and gasket
ECM (Engine Control Module)
Reduction drive vent
Reduction drive dipstick
Coolant hoses to the radiator (never delivered)
Heater hoses to the cabin (never delivered)
Shipping crate (never delivered)
The engine was delivered with the following defects:
Incorrect wiring on the engine wiring harness
Incorrect wiring on the throttle sensor
Incorrect engine parameters on the ECM
Incorrect hole size for the bushings on the prop flange
Numerous oil leaks on the engine valve covers
Coolant leaks on the engine (these have stopped)
Oil leak on the reduction drive
Low fuel pressure
Engine tachometer configured for the wrong engine
It took them 5 years to deliver a defective engine that left their factory without ever being test run. They still cannot get it working and have broken every promise to come and get it running.
I will leave you to make your own conclusions, but I have determined that it is unairworthy. It is not even fit for a ground vehicle.