information

jim_geo · Post by **jim_geo** » Fri Nov 26, 2004 1:24 am

I’ve been visiting the subject of engines with an auto mechanic friend of mine. He like us has a background in aviation. He is a one time owner of a Cessna 140, then the owner of an ultra light and lastly an owner of an ASW 15 meter Sailplane. He specializes in late model foreign and domestic auto repair. Most of his diagnostics if not all are computer generated. Because of his experience with foreign motor works and my experience of him as a careful and thoughtful person not to mention the trust I have for him with my own auto I value his opinion highly. He knows of my desire to build an RV. I have asked him what his opinion is in regard to using a Subaru engine in an aircraft. What follows is summary and paraphrase of what he said.

Larry: They leak oil and they weep coolant from the head gasket. On the oil side, big deal a Lycoming engine throws oil over board on a regular basis. On the coolant side, the coolant weep is external and he has never seen it weep or leak coolant internally. In other words the coolant weeps out of the engine rather than into a cylinder or into the oil. Those are the only negatives about the Subaru engine that he could think of. He went on to say that he has never seen or even heard of a sucked valve on a Subaru engine. He has never had to replace an engines computer. An important point since loosing a computer mid flight could be a disaster. He feels that they are well balanced and very smooth running.

Personally I am sitting on the fence. A couple of things that appeal to me personally about the Subaru are the facts that parts are readily available at my local Subaru dealer and that cabin heat is taken off of a coolant cooling radiator rather than using an exhaust gas heat exchanger. On the negative side the choice of props is limited at least in the case of the Eggenfellner conversion to MT composite props. I would like to use a Hartzell CS prop. My considerations for Hartzell are performance as well as money.

I’m posting this here in the hopes that I can get some of your opinions pro or con about Subaru and Lycoming engines. I’d really like to know what others have found out.

captain_john · Post by **captain_john** » Fri Nov 26, 2004 9:44 am

I am on the fence about the 2 engines as well. Costwise, they are about the same. That is the only similarity.

From my perspective, here is an overview:

Subaru "Pro's":
Technologically superior in every aspect
Great heat for New England winters
Reliable cold engine startups
Quieter operation
Uses an On Board Diagnostics computer for easy troubleshooting

Lycoming "Pro's":
Tried and true
Van's engineered to an honest "fit"
Operates at the proper RPM (read: NO gear REDUX)
More A&P's would be willing to work on them
Can be fitted for inverted use

Coincedentally, 5 apiece!

Can anyone think of more?

CJ

Post by **Spike** » Fri Nov 26, 2004 10:32 am

All depends on how you look at it I guess. Personally I dont think that superior technology in itself is a pro. It in itself may facilitate aspects that are "pros" but to me the fact that the technology is superior neither adds or takes away from the desirability. I actually look at it as somethng to break

As far as the Lycommings, I think their biggest boon right now is the 100LL problem. I dont think we will every see a gasoline based engine turning that slow of an RPM putting out 180+ HP without lead. I believe that to keep away from gear reduction the diesel is the only way. Outside of that though the Lycommings really are hard to beat. They are not only proven, but dirt simple. There are more parts in my Briggs and Stratton lawn mower.

Dont get me wrong, I susport Eggenfellner. Might even have one in mine when I get that far. What I dont agree with are those that speak poorly concerning Lycomming now that there are "more advanced" engines out there. I dont believe that latest is alwasy greatest.

-- John

aerial · Post by **aerial** » Fri Nov 26, 2004 2:52 pm

Captain_John wrote:I am on the fence about the 2 engines as well. Costwise, they are about the same. That is the only similarity.

Can anyone tell me where to find information on the new Honda-Continental joint venture? When it is to be released and what the cost will be? I have an IO-320 for my project but being a former motorcycle enthusiast I know it would be hard to beat Honda reliability or engineering.

Post by **Spike** » Fri Nov 26, 2004 5:18 pm

I believe right now that Honda is keeping that information very close to vest. Like you, I would *love* to know that information.

-- John

captain_john · Post by **captain_john** » Fri Nov 26, 2004 5:52 pm

I dunno where I heard it, but the rumor mill told me that they had plans of going direct to the certifcated market.

Too bad, really.

CJ

Snap · Post by **Snap** » Fri Nov 26, 2004 11:18 pm

Dont get me wrong, I do like Lycoming engines (they are simple) but the thing I dont like about them are the Magnetos. Now I get this from flying helicopters. When they go, they go! Not so bad in a fixed wing but in a Heli, can be very uncomfortable. It is like someone has hold of the tail and is giving it a hell of a shake. Not to bad for me becuase I know what is going on but for the passengers, it is very scary.

Then there is the cost of fuel. AVGAS is more expensive and on its way out (if you believe the hype). AVTUR is becoming more available around the country (Australia). In the OUTBACK even more so.

Centurion 1.7 engine is certified in Europe and I think in the US now. If not it will be very shortly and seems to be about he same cost as the 360 style engine. Plus's for this engine

1. No Mags
2. Avtur
3. 17lts/hr fuel burn at lower cost (Lyc is 38lt/hr)
4. Water cooled
5. Constant Spd single lever
6. Dual FADEC
7. if loss of coolant, can run indefinatly at 55% pwr which will give us RV'rs about 120-150kts (acft specific)

I know what I want. What about you.

You can go further on less fuel so your AUW will be less=better performance, greater safety and BIGGER RV GRIN!!!!!!!!!!!!!!!!!!!!!

What do you think. Please flame away

captain_john · Post by **captain_john** » Sat Nov 27, 2004 8:56 am

Oh yah, one more pro for Soob... more efficient on fuel!

Snap, mate... what is AVTur? I am guessing it is a substitute for AVGas, but some details please.

Color, octane, price, performance, characteristics and is it compatible when used in the same tank? I have never seen it in my travels. Of course, I don't make it down your way often! Maybe when the plane is done!?

CJ

nightflyer · Post by **nightflyer** » Sat Nov 27, 2004 10:51 am

CJ, Avtur is short for aviation turbine fuel. Not a term we use in the States. Think Jet-A.

Snap · Post by **Snap** » Sun Nov 28, 2004 6:04 am

Sorry about that. Keep forgeting that you folks don't use the same term as us downunder.

Other names for it:
AVTUR
JETA1
JP1
AVCAT (marine grade turbine fuel)anti corosive additive
F34 (JetA1 with FSII(fuel system icing inhibitor))
F35 (plain JetA1)

I can go on for ages.

captain_john · Post by **captain_john** » Sun Nov 28, 2004 8:26 am

Hahaha, I see,

How about diesel and Kerosene?

CJ