Jabiru 3300

[avidflyer]

I have a 2200 Jabiru in the Avid that I crashed. I put about 400 hrs on that engine, and eventually I plan to fly it again once the plane is rebuilt. As far as props that don't move air near the hub, Warp Drive comes to mind right off the bat. I did run one without problems though. Wood props are carved/curved much closer to the center than the Ward Drive. I think the 3300 is harder to cool than the 2200 also. I haven't put any time on a 912 yet, but that is the engine I would go with judging from what I've read and heard. Lots of happy though poorer people running them. Keep your eyes open, a good used one will come along if you can wait for it. If you are just starting to build, it'll be a while before you need the engine anyway. That's my 2 cents worth, and worth every penny you paid for it! LOL Take care, Jim Chuk

[Esser]

If you build a proper air tight plenum you should solve all your heat issues. Ever notice that Reno Air Racers running these mammoth engines have smaller cooling intakes on their planes then the kitfox has? Most peoples air cooling set ups waste a ton of air. A good air tight plenum uses every piece of air coming into your cowl to cool. A book that has a good chapter on this is Speed with Economy by Kent Paser.

http://www.actechbooks.com/products/act585/

[avidflyer]

I agree that the different props affect the cooling on the ground more than in the air. Here are pics of two different props I ran on my plane and you can see how the wood prop would push more air into the cooling ducts on the ground than the Warp drive prop would. As I said, I didn't have problems with my Warp Drive and cooling, but up here in MN. it is seldom more than 80 F when I'm flying.... maybe 20F to 50F more likly. Take care, Jim Chuk

[kitfox5v]

Thanks guys, Keep them coming. Any information will help us all. I love this forum. It's nice to have fellow builders input. I'm not ready yet so maybe they will have all problems solved by then. I just don't believe running a 912 5000 plus just to spine a prop 2000rpms is cost effective in the long run. just seems like alot of wear to me.Thanks Eddie Kitfox5v

[Av8r3400]

I just don't believe running a 912 5000 plus just to spine a prop 2000rpms is cost effective in the long run. just seems like alot of wear to me.

Over 40,000 of them sold with millions of hours of flight time would disagree with that.

I can't understand why these engines are hated so much for being efficient and reliable.

[jrevens]

Over 40,000 of them sold with millions of hours of flight time would disagree with that.

I can't understand why these engines are hated so much for being efficient and reliable.

I agree... they're "torqueier"- will turn more prop for their weight & horsepower than just about any of the competition & hence outperform in climb & cruise, perhaps the lightest weight "package" available, ceramic coated cylinders giving very low oil consumption & negligible wear throughout their life, 2000 hr TBO with examples going far longer before teardown, absence of shock-cooling issues... I could go on & on. I never knew too much about them & therefore wasn't a big fan, but I'm convinced that they are a great engine now.

Sorry if this post should be in the Rotax category

[TahoeTim]

The Jabiru is a great engine. Runs smoother, simple to maintain, and has great power without a gear reduction, multiple carbs, cooling system, etc to worry about.

I investigated my options before spending $20k plus on an engine. Hopefully you have figured out that the Rotax is not the lightest package by any stretch of the imagination, nor is it cheap to operate over a 10 year period. Look at fuel consumption, annuals, and overhauls in the total picture. Reliability is equal since neither engine is causing planes to fall out of the sky. I think the rotax is passed over by those of us that hate a PSRU and high maintenance costs.

OBTW - you can hand prop a Jab in the back country if your battery goes dead.

The single most expensive purchase will be your engine. It costs more than a kit so be careful. Like the plane, you will have to live with your decision. Forget about shock cooling and step climbing. IMHO, anytime you are zoom climbing or quickly descending you are flying unsafe. Just because a rotax handles those two scenarios better doesn't make that sort of flight safe.

[Esser]

Thanks guys, Keep them coming. Any information will help us all. I love this forum. It's nice to have fellow builders input. I'm not ready yet so maybe they will have all problems solved by then. I just don't believe running a 912 5000 plus just to spine a prop 2000rpms is cost effective in the long run. just seems like alot of wear to me.Thanks Eddie Kitfox5v

There are a few differences you have to look at with that too. The biggest one being displacement. A 912 is roughly 1200cc and a O-200 is 3300cc yet they run the same horsepower. The 912 has a shorter stroke and because of this can run at a higher RPM easier (Due to easier balancing, slower piston speed, etc). It gears down its high RPM to a lower shaft speed and gains a mechanical advantage for this. Because of this mechanical advantage I wouldn't say there is anymore wear and tear than an engine with a long stroke/low rpm that is doing all the work off the cylinders. The one trade off with the high rpm is you usually gain peak power but lose torque.

It is just two different ways of skinning a cat. Much like a 4.3lFerrari engine that makes 500hp and a 7.0l corvette engine making 500 hp.

[War Eagle]

While the gear box reduces the engine speed so it can keep the prop tip speed at a reasonable number it also multiples the torque out put of the engine.

As an example: if your engine generates 100 hp and 50 ftlbs of torque at 5800 rpm and you add a gear box with a 3:1 ratio then you now have 150 ftlbs or torque delivered to the prop. Horsepower doesn't change but the torque to drive the prop is multiplied by the gear ratio.