The great debate continues. Buy a 4 seat certified plane or a small 2 seat experimental.

Does any one have experience with a Subaru E81 engine? Been looking at a Rans with this engine & I don't know anything about them.

Yes I know "buy a Rotax 912" for it, but I don't feel this plane is worth a conversion. If the engine is no good then I would be better to spend more for a Rans which is already set up the way you want.

Thank you Gents.
byeBill

P.S. I could not find any info for this engine in a search on it.

My buddy Hal is the expert on E81's in Rans S7's. He doesn't do computers or emails though so if you send me your phone number, I can ask him to give you a call. Hal had an E81 in his Rans up until a few months ago when he switched to a Rotax. The plane lost a lot of weight when he made the switch. I can't recall exactly how much but I think it was in the order of 100lbs which is a $hit load for that size of plane. He likes the way it flies much better with the Rotax. He had a couple of forced landings courtesy of the E81.

NO Thank you Subaru engines ! Have a hanger neighbor who had one in Rv-6 egginfelter never could get it to cool down - another friend who bought one for his Glass star and lost engine several times on first flights both pulled and engines changed to proper aircraft engine. Subaru makes a good little car but no thank you on aircraft engine .

I got no dog in this fight, but I'm pretty sure the E81 was developed as an aircraft engine, then put into automobiles after Subaru left the aviation market.

But I could be wrong...

They are known to have good strong bottom end, the big metal moving pieces. But more than a few problems have happened in aircraft use, almost all in the ignition/fuel/computer side of the game.

One airplane I heard about in Camarillo, CA had a very minor problem with an injector or spark plug, and the engine's computer went into the "limp home" mode, where it only made 25% power, and lit up the "service engine light". This was apparently not a welcome event just after he took off, so the airplane slowly settled back into a farm field with the pilot unable to do anything but not turn the airplane and sit there screaming. Lesson learned: disable the "limp home" feature on the automotive computer. In fact, I believe there are people who specialize in knowing what settings and curves and features have to be changed when you put the Subaru into an airplane. If you are considering this engine for aircraft use, I would certainly go to one of those people and make sure you have all the right settings and parameters.

That being said, once the right setup has been achieved, I believe there are quite a few Subaru powered aircraft flying with reasonable safety. But you will find two or three "orders of magnitude" more Rotax powered airplanes flying with a reasonable amount of safety. I'm not a huge fan of the Rotax, but the numbers don't lie.

But hey, what the hell... it's not like you fly in any kind of remote areas or anything, where an engine issue could result in you being cold at night or have to walk a couple of miles to get help, is it?

I believe Courier Guy built a Subie-powered S7 which he put a lot of hours on- in fact, he wrote a magazine article about it years ago for "Sport Pilot" magazine (before LSA/SP came along). That's who I'd ask about it- he's been there & done that. Don't know if he got the t-shirt though.

My EA 81 conversion, bought complete from the now defunct Stratus was dirt simple and gave me zero problems for 1300 hrs, then I sold it and bought my long tail S-7 kit. No computer so no problem there either. I paid 5300 bucks for it, 912's were only 80 horse then, no 100 912S, but even the 912's were, I think, 12 K or so! So a huge savings, especially as I was even poorer back then. It was an honest 100 horse too, in fact Stratus head Reiner Hoffman (his strong Germanic accent gave everything he said a ring of high techness and engineering wazoo, but in fact he appreciated keeping things simple) told me it/my engine spun up a prop 300 rpm faster then a strong 0-200 did.

Cooling was never a problem with the belly radiator RANS was using back then ('94) plus the oil pan sticking out of the cowl bottom (like a J-3's jugs) took care of the oil cooling! The heads also stuck out the cowl, so no problems there either. I had always planned to fair everything in at some future date, but it flew fine as was and really didn't look all that bad once I painted the visible Soob parts to match

But...it was draggy that way, and come to think of it, I never did anu dead stick ridge soaring like I do in my Rotax powered S-7S nowadays, that says a lot right there. It was 40 to at most 50 lbs heavier then a Rotax install, not even close to 100 more. Sure I had it balanced out, but that took lead in the ass end, permenantly, plus I could never fly it truely empty, I always had to have some junk in the trunk. This was no problems on xc's of course, all was good then, local and solo I was always on the front edge of the cg range.

Due to the draggy cowl it was a bit slower and used more fuel, 4.3 gph, then my current bird does. The weight and the size, that's the big deal for a plane like the S-7 (tandem), something like a Highlander could at least fit it in that wider cowl, but you still have the weight issue. I am always amazed when some pilot thinking of getting an LSA type bird casually mentions that of course he would of course have to put a Continental or Lycoming in his whatever brand, like that much weight extra is a trifle! I have never heard of a Rotax pilot going to an auto conversion of any type, they work so damn good and are so light it makes the high price almost painless, almost.

That's something I could never understand: A guy spends tens of thousands on a kit and everything to go with it, but then turns cheap and want to put a $1500 VW motor in it...

The last place I (personally) would ever want to go cheap would be in the motor on my airplane.

I always figured that 1/3 of the investment in an airplane should be in the motor.

Thank you gents.

I read between the lines that the Subaru engines are for fun but possibly not comfort when over the Frank Church Woods.

Thank you,
I will probably seek a certified bird & then work a Homebuilt in at a later time when I secure a bigger garage to scatter more things across the floor.

byeBill

My only experience with the Subi engines is in VW van conversions. They have a few issues, one is they leak. The heads tend to leak, so badly that Subaru will give you their magic leak stop fluid for free. Not all do, but enough that they had to resort to this solution. They tend to be fairly bulletproof, compared to VW water boxers. Now you will have loads of folks rave and rave about them on the message boards, but when I see them up here in Flagstaff (a fairly common destination for your average VW Westfalia camper) they are on the side of the road with the engine compartment lid up. I have come across more than one, tricked out Vanagon Syncro (the 4WD version) on the side of Lake Mary road. I ride there several times a week, so I would stop and lend a hand. I just happen to have had a VW Syncro Wesfalia, but I put a bored and tuned VW water boxer in, as it was marginally more relable at equal HP to the Subi. I saw many blown heads on the Subi from overheating and one that crapped all its oil out the lower end. Now this is a conversion that is trying to push a heavy van up at altitude, using almost all its available Hp continuously. Kind of like an airplane, come to think of it.

Funny anecdote about the van: When it had the original water boxer in it, going up a shallow grade on I-40 near Kelso road (middle of nowhere). My wife looked over at me and said, "is this as fast as it will go." There's something you never expect your wife to say. Led to me getting the pumped up engine. Ultimately, it was a cool van that needed you to have AAA platinum towing, as it would kill yet another component, you never heard of, at the most inopportune times. Nice thing, very collectable and it sold for $45K, wife got a new Tiguan out of it.

There's an Avid guy that flies all over Alaska with his. That says volumes to me.

cessnaford wrote:Thank you gents.

I read between the lines that the Subaru engines are for fun but possibly not comfort when over the Frank Church Woods.

Thank you,
I will probably seek a certified bird & then work a Homebuilt in at a later time when I secure a bigger garage to scatter more things across the floor.

byeBill

What reading between the lines?! What part of 1300 trouble free hrs isn't perfectly clear? And yes, all over the Frank, as far east as Michigan, to the west coast a few times, and all over the western states (at their high altitudes) in general. Before SPOT and PLB's for what that is worth. The bad installs get all the notice I guess, even in VW vans! I was the only respondant to your query with actual first hand flying experience with the EA-81, not second hand, and other then the stated issues with size and weight, it was a great choice for me. I say all this as I feel you were looking for an excuse to stay with what you know better, certified aircraft engines, and you heard only what you wanted to hear. Nothing at all wrong with that! By all means go certified if that is where your comfort zone is, and by the way, anyone flying anything over the Frank that isn't a bit apprehensive is braver then me. I do have to say the true dual ignition of the Rotax is somewhat more comforting then the single I had in the Soob

I built my avid flyer in 1996. When it came time for a motor I went with a Stratus EA81 engine package. After a 150 hrs I added a ivo inflight adjustable prop. It was a great combination . Flew it to almost every airport in the fly Idaho backcountry book . All the western states except Alaska. I sold it with a little over 500 hours of trouble free flying. I needed something with more room . I love my 180 but miss my Subaru avid .
Good luck whatever way you choose to go .

WE/I ran the e81's in my hovercrafts for years, same work load as planes only wetter. We eventually upgraded to the 2.2 and 2.5 because of the extra power. They were BULLIT PROOF. The only guys that had problems in planes and the hovercrafts were the guys that did not know what they were doing when it came to the install. OF COARSE IT WAS ALWAYS THE MOTORS FAULT.

I purchased a damaged Murphy Rebel many years ago that has a Formula Power Subaru conversion installed. I spoke to the original builder of the plane before it had been sold and wrecked (in 2 days). The builder stated he had good service with it and had flown it 300 hours trouble free before selling the plane. He did like the smoothness and 'car like' attributes of the engine. Great heater, easy starting in winter, low maintaince, etc. His only negative statement was that when he first installed the engine it had a hesitation/flat spot at around 3500 RPM. His installation was written up in CONTACT, the alternative engine magazine.

Have a customer here with a Subaru powered Kitfox 4... He bought the aircraft with the engine installed... Had a few "growing pains" getting it to run smooth for the first few months he flew it. But, he got it worked out and it now fly's and runs really well... I don't remember the exact conversion but it has a duel ignition setup and an adjustable 3 blade electric prop... The thing is so quite in the air that he has flown in a couple of times and I never heard it overhead....

Brian.