Can anyone shed some light on over heating problems with the 3300 late model engines. Thanks
Can anyone shed some light on over heating problems with the 3300 late model engines. Thanks
I don't know anything about the Jabaru in a Kitfox but I have a hanger neighbor that has the 3300 in a Zenith 601XL.
He has to watch his temperature a lot. He has told me that the prop he is using does not move enough air into the cooling vanes on the engine. Supposedly there is limited air flow into the engine near the propellor hub.
I understand there are some props that move more air near the hub than some others.
When I was at Arlington one year I spoke to the Jabaru dealer there and he mentioned the specific need to have enough air flowing over the engine and that some props were better than others. I don't remember which props he suggested. As I recall he also named some that were bad actors when it comes to moving air at the hub.
Thanks War eagle, Im building a 5 and just looking at all options. Im not ready yet but just wondering. How do you like your rotax?
When I first investigated building a Kitfox I talked to as many people that owned or built Kitfoxes that I could find.
That amounted to several dozen people. In my discussions the powerplant options always seemed to be a part of those discussions.
I was biased against using any kind of engine that required a gear box or speed reduction. I thought the extra complexity compared to a direct drive engine was a reliability issue.
But after talking to Kitfox owners and doing a fair amount of reading and talking to other people like Lockwood, Rotech, Lycoming and a few others I began to hear great things about the reliability of the Rotax series 9 engines.
I looked at aircraft sales and saw the Rotax installed Kitfoxes were getting better sales prices than some other engine combinations.
The short of the long story for me was that I completely changed my bias against Rotax engines and there we several things that did it for me, but the reliability, technical experience factor of Rotax manufacturer, power to weight ratio and the resale value were big hitters for me.
Now not everything is perfect about Rotax. One of those is price. They are very expensive. A lot to do with that is the weak US dollar. But recognize most things to do with airplanes are expensive, but there are other power options for the kitfox that are less expensive than the Rotax if you are just comparing acqusition price.
But I tried to look at the whole value proposition associated with the purchase of a Rotax engine and when I did that I came to a conclusion that Rotax was a better choice for me.
There are specific things you need to do to take care of the engine but it has been strong and reliable for me and I am happy with the choice.
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
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/
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
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.