Subie EA-81. What do we think of them?

D

docmirror

Touchdown! Greaser!
Joined
Jan 5, 2007
Messages
12,008
Display Name
Display name:
Cowboy - yeehah!
I've heard some horror stories of the Enginfellner(sp?) conversion, and I've heard some really great thing about the Subie otherwise.

Looking at a EXP plane with a Subie EA-81 and a reduction drive on it. Says it puts out ~100HP.

According to some sources, the engine was first developed for the light aircraft market, and then Subie gave up and put it in the -- get this, Brat.

Not really worried about the power side of things but of course wondering about the reliability aspect. 1.8L should be able to put out 100HP pretty easy with the right C/R and intake.

Would YOU fly behind one(properly built and tested of course) ??
 
For comparison, the VW air cooled puts out 80HP from 2.18L. I know quite a bit about the VW air cooled, but almost nothing about the Subie.
 
docmirror said:
I've heard some horror stories of the Enginfellner(sp?) conversion, and I've heard some really great thing about the Subie otherwise.

Looking at a EXP plane with a Subie EA-81 and a reduction drive on it. Says it puts out ~100HP.

According to some sources, the engine was first developed for the light aircraft market, and then Subie gave up and put it in the -- get this, Brat.

Not really worried about the power side of things but of course wondering about the reliability aspect. 1.8L should be able to put out 100HP pretty easy with the right C/R and intake.

Would YOU fly behind one(properly built and tested of course) ??
Click to expand...


Properly built with a dependable redrive, yeah the Subie is a good alternative motor......

If Jan Eggenfellner had his hands anywhere near it.. I would NOT even put it in a go cart....:no::no::no::no::nono::nono:
 
A good friend totaled his RV-9A in one after the engine quit at 41 hours. He escaped with minor injuries. The person in question changed the company name and is now doing Honda conversions. I would not touch a subie, do the research.
 
Is there a EJ22 swap, thst was one heck of a motor, or at least in the cars.
 
N801BH said:
Properly built with a dependable redrive, yeah the Subie is a good alternative motor......

If Jan Eggenfellner had his hands anywhere near it.. I would NOT even put it in a go cart....:no::no::no::no::nono::nono:
Click to expand...

Seems to me that cooling is always an issue and the performance is never as expected from the vans forum posts I've read.
 
Fuji Heavy Industries, Subaru's parent, did make aircraft engines, but the Subaru boxers are not descendants. That was imagined by someone and has been repeated enough to stick, but it's not true.

The EA-81 is an old design which was originally rated below 100 HP in cars. It's heavy, but could be reliable if the external systems are done right. The EA-82 was a later update with better heads, but still not a great power-to-weight ratio.

The EJ22 2.2L engine debuted in the early 90's in the Subaru Legacy, and the core was very dependable. Most failures stemmed from user mods, not OEM parts. These things can go 2000 hours or more if the external systems aren't screwed up.

The EJ25 2.5L engine had initial problems with head gaskets, but the bugs have been worked out. The newer EJ20 is designed for turbocharging with stronger internals, but not many have been converted.

As for the Eggenfellner failures, don't confuse those with deficiencies in the engine itself. Reduction drives were the primary issue there, along with some issues related to inaccurate dimensions provided for the six-cylinder engines. I'm not sure the lessons have been learned. There are reports of inconsistent quality in the outsourced gears in the new Viking reduction drives (Honda Fit engine core).
 
Hanger neighbor retired Area 51 engineer built a gorgeous Europa over a 13 year span interrupted by lots of cruises with wife & other travels but eventually got it done. Instead of the Rotax the Europa was designed for, Wayne, being an engineer, put in about the most complicated 1.8 Subaru installation you can imagine. Supercharged (not turbo), water cooled with a couple different radiators, extra oil coolers, reduction drive, dual screen GRT, long range tanks, CS prop, the works. Looked incredibly well done and incredibly complicated. First flight he got it sideways on landing since the monowheel and outriggers didn't work the way he expected so he bought the kit and converted it to a tri-gear. First flight after that the engine blew and he set it down on a freeway close to the airport, no damage. The verdict was the camshaft gear broke some teeth & internal destruction ensued. So he parted out or trashed everything firewall forward, bought a Rotax & installed it (another immaculate installation), built a new cowling, lost his medical and sold it for less than 20K and moved to Branson. He had at least 100K invested not counting 13 years of hangar rent.

The Suburu in theory seems like it would make a good aircraft engine - basically a water-cooled Type 1 VW which makes an excellent aircraft engine if done correctly - but without knowing what I'm talking about and based just on overall impressions and hearsay over the years, I don't think I'd want a Subaru powered airplane. Water cooled, heavy, especially if you throw a reduction gear into the mix.

I'd talk to Pat Panzera at Contact Magazine for an informed opinion.
 
Last edited:
From what I'm able to gather just in internet research without going and looking at anything the Subie installs range 1 good one to 1-2 bad ones. Lots of systems that need to be carefully considered and after that, the cost is pretty close to a Jab 2200 air cooled. I think I'm going to stay away from them. Also notice the Subie powered planes for sale typically have very low total hours. I think that means something.
 
docmirror said:
From what I'm able to gather just in internet research without going and looking at anything the Subie installs range 1 good one to 1-2 bad ones. Lots of systems that need to be carefully considered and after that, the cost is pretty close to a Jab 2200 air cooled. I think I'm going to stay away from them. Also notice the Subie powered planes for sale typically have very low total hours. I think that means something.
Click to expand...

Jabiru's are having their issues too....:rolleyes:
 
An auto conversion that will 'actually' have the reliability of an aircraft engine will cost 3X to 10X the price of just putting a Lycosaurus in it.
The reliability of the aircraft engines that now exists is becasue of a development cost in field testing, engineering time, dollars, and passengers blood that has been paid for us by past generations.
The auto conversion has not.
Even Porsche could not pull it off.
And even with using aircraft engines the experimental fleet still has an engine failure rate several times that of certified aircraft. It is not just the engine, it is every bolt, coupling, rod, baffle, hose, fuel tank, pump, etc. etc. that has to be 100% reliable AS INSTALLED.
 
Dr. O said:
It is not just the engine, it is every bolt, coupling, rod, baffle, hose, fuel tank, pump, etc. etc. that has to be 100% reliable AS INSTALLED.
Click to expand...

This is kind of where my thinking is going. I read a pretty nice write up on a guy building his own intake manifold out of carbon to get away from the cooling crossover and increase the size of the intake. It all sounded so good but I was wondering if he did any acoustic coupling tests on it to see if it vibrated at any RPM? I'm pretty sure the answer is no, and at some point I'll always be wondering if that fancy carbon intake is seconds away from shattering and all the bits going into the engine, then gas spewing all over the top of the hot engine. At that point, an Al intake starts to look a lot better.
 
From what I'm able to gather just in internet research without going and looking at anything...
Click to expand...
"THIS LOOKS LIKE A JOB FOR...(you know who)."
- Duck Dodgers

I went into my 1998-2013 homebuilt accident database and extracted the Subaru accidents. I included Eggenfellner, NSI, and Stratus engines. Considering the usual types of airplanes involved, I extracted the Lycoming O-320 accidents as a control group. I did not include any of the aftermarket engine cloners or anything listed as a modified engine.

There were 172 total Subaru accidents, and 453 involving O-320s. However, over 40% of the Subaru accidents (43%) were on rotary-winged aircraft, while only 3% of the O-320s.

Gyros have an advantage in an engine failure; they're basically already configured for an emergency descent. Engine failures are thus less likely to end up as recorded accidents. So I weeded out the rotorcraft and looked solely at fixed-wing accidents.

That left 97 Subaru-powered homebuilts and 439 O-320-powered planes.

To me, the first statistic is one of the most important ones: What percentage of the accidents began with an engine failure. The failure may not be the engine's fault; it could be fuel system problems or the pilot's running out of gas. But when you're comparing engine types, one can assume the portion of pilot/system-related accidents were similar. For a point of reference, 15.2% of Cessna 172 accidents and 18.2% of Piper Archer accidents begin with the engine stopping. I haven't done that many production-type airplanes, but the worst so far has been the Cessna 210: 31.6% (one out of eight 210 accidents is due to fuel management).

For the overall fixed-wing homebuilt fleet, 33% of the accidents started with an engine failure.

For the O-320 powered fixed-wing aircraft, it's 29.5%. Better than overall.

The Subaru group? Over half: 52.6%.

Looking at the causes (percentages are of total number of accidents):

Engine internal issues (rods, bearings, etc.): 5.2% Subaru, 1.4% O-320.

Ignition/Engine Controller: 9.3% Subaru, 1.4% O-320.

Reduction Drive: 3.1% Subaru, none on the O-320s (remember, this is fixed-wing only).

Cooling System: 6.2% Subaru, none O-320.

Fuel system in the engine compartment: 3.1% Subaru, 0.9% O-320.

Almost ten percent of Subaru-powered fixed-wing homebuilt accidents are due to systems the O-320 doesn't need... Propeller Speed Reduction Units and liquid-cooling systems.

Despite there being more than four times as many O-320s in the accident lists than Subarus, the Subaru group showed more cases of ignition system/engine controller issues and practically as many internal engine failure cases.

Ron Wanttaja
 
Last edited:
docmirror said:
I've heard some horror stories of the Enginfellner(sp?) conversion, and I've heard some really great thing about the Subie otherwise.

Looking at a EXP plane with a Subie EA-81 and a reduction drive on it. Says it puts out ~100HP.

According to some sources, the engine was first developed for the light aircraft market, and then Subie gave up and put it in the -- get this, Brat.

Not really worried about the power side of things but of course wondering about the reliability aspect. 1.8L should be able to put out 100HP pretty easy with the right C/R and intake.

Would YOU fly behind one(properly built and tested of course) ??
Click to expand...


With a PSRU I would reluctantly fly behind it (I had a Brat, reliability was not its long suit.), Direct Drive I don't like on any automotive engine because the crank and journal are not designed to endure the gyroscopic forces of a prop. If there is a bell housing with a support bearing, that makes it acceptable.
 
There's a Subie on ebay right now for sale with a PRSU and prop. It's the whole enchilada and I have to think out there somewhere is a plane with a Jab or Rotax that started life with the Subie, but the pilot just got frustrated with all the issues, and gave up.
 
docmirror said:
There's a Subie on ebay right now for sale with a PRSU and prop. It's the whole enchilada and I have to think out there somewhere is a plane with a Jab or Rotax that started life with the Subie, but the pilot just got frustrated with all the issues, and gave up.
Click to expand...

That happens a lot with both Subaru and VW powered projects. Many of the rest of the auto conversions go the same way. It's not particularly simple, and auto engines neither have the crank and case meat to direct drive a prop, they also don't have the piston diameter to properly take advantage of the fuel's burn properties at those RPM. Better to use a PSRU and let the engines turn up.
 
docmirror said:
There's a Subie on ebay right now for sale with a PRSU and prop. It's the whole enchilada and I have to think out there somewhere is a plane with a Jab or Rotax that started life with the Subie, but the pilot just got frustrated with all the issues, and gave up.
Click to expand...

It really seems to be a case of you get what you pay for. People keep chasing the dream of the auto conversion to save money. Even people buy Jabirus to save money over the Rotax and the results are pretty much the same. If you want proven reliability and the minimum risk exposure due to engine failure, it really seems you have to pay for it.
 
Dav8or said:
It really seems to be a case of you get what you pay for. People keep chasing the dream of the auto conversion to save money. Even people buy Jabirus to save money over the Rotax and the results are pretty much the same. If you want proven reliability and the minimum risk exposure due to engine failure, it really seems you have to pay for it.
Click to expand...

The only times I see using an auto conversion is when I need over 350hp or go Diesel. Cheap, yeah, that's not happening. There are advantages to be had with auto conversions especially for high flying planes. Liquid cooling has its advantages. I would use a Lenco stage for my 2 speed PSRU.
 
Dav8or said:
It really seems to be a case of you get what you pay for. People keep chasing the dream of the auto conversion to save money. Even people buy Jabirus to save money over the Rotax and the results are pretty much the same. If you want proven reliability and the minimum risk exposure due to engine failure, it really seems you have to pay for it.
Click to expand...

Yeah, that seems to be the case. I was looking at the almost perfect plane, at an attractive price - but powered by the Subie. Guessing that removing and selling the Subie then powering it with the 'right' engine would be more than just buying the right plane with the right engine to start with.
 
docmirror said:
Yeah, that seems to be the case. I was looking at the almost perfect plane, at an attractive price - but powered by the Subie. Guessing that removing and selling the Subie then powering it with the 'right' engine would be more than just buying the right plane with the right engine to start with.
Click to expand...

Maybe, maybe not, but most likely. Sometimes when people get to a certain point of frustration, deals occur.
 
> "Jabiru's are having their issues too...."

Huge issues. Wouldn't go near one.

> "Better to use a PSRU and let the engines turn up."

PSRU's cost in weight, added complexity, and HP lost having to turn more gears and doing two 90° directional changes in going from crankshaft to the prop. As for turning up the RPM's, more RPM's mean more friction which costs power and generates heat. Friction increases exponentially with RPMs so the lower you can turn the engine while extracting power with manifold/cylinder pressure, the less power will be lost overcoming the additional friction of high RPM's. That results in lower temps and a much more efficient and cooler-running engine. Think of Lindbergh teaching the P-38 pilots how to operate their engines in the Pacific. Rotax seems to get away with running high RPM's but I still don't like an aircraft engine that sounds like a lawnmower nor one that depends on a PSRU with it's built-in power drain. I'm just prejudiced obviously . . . they've proven themselves to be decent engines.
 
You must log in or register to reply here.
Back
Top