Can anyone shed some light on over heating problems with the 3300 late model engines.:confused: Thanks
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Can anyone shed some light on over heating problems with the 3300 late model engines.:confused: 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 http://www.teamkitfox.com/Forums/ima...ons/icon10.gif 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:)
Over 40,000 of them sold with millions of hours of flight time would disagree with that. :)Quote:
Originally Posted by kitfox5v
I can't understand why these engines are hated so much for being efficient and reliable.
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.Quote:
Originally Posted by kitfox5v
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.
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.
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.Quote:
Originally Posted by Av8r3400
Sorry if this post should be in the Rotax category
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.
I hope we can keep this thread civil as it is a good discussion. As Tim pointed out your engine is a big investment so folks get pretty passionate about their decisions. I, for one, am glad there are options, the more the better. Which is best is likely to be one of those debates that will go on forever hopefully with ocasional new choices thrown into the mix. I chose the Rotax because it was the most common and best understood power plant for this plane. I also don't like having a reduction unit but it does provide one solution for the following engineering challenge. To optimise the prop based on desired performance envelope will result in the best length, pitch and RPM. To optimise an engine for best HP/weight and other considerations will also result in a best RPM it just wont be the same as the best RPM for the prop. A direct drive engine will compromise these two in exchange for simplicity (a very real advantage in an airplane engine). Consider the following relationship (this has a bunch of hand waving but I believe basically correct). For constant tip speed and static thrust HP needs to increase linearly with the prop RPM at which it is produced. This is to say that if you have 20% more HP at 20% higher prop RPM (and therefor a 20% shorter prop) it should be about a wash in static thrust.
Dorsal, Thanks for the info. That is why I started the thread. I just want all the info I can get. This is for sure the 2nd biggest investment on our project. Or as may wife said, the reason she upped my life ins. as you said, hope we can keep this civil because some rotax people are closed minded on this subject. Thanks again, Eddie;)
Not wanting to quibble about things, but a few posts back it was mentioned that you can hand prop a Jabiru. The standard Jabiru ignition needs about 300 RPM to make spark. I know I was never able to spin my 2200 that fast by hand. Kind of interesting though, the 582 Rotax also needs about 300 rpm to make spark. Having the gear box will let you hand prop it if you really flip it fast. Good thing to, my battery was nearly dead today, and so I fired it up by hand. Got some nice flying in afterall! Take care, Jim Chuk
PS I've never heard of anyone handproping a 912 even though it has a gearbox. Anyone done it?
Yes. I've done it twice on the 80 hp but that was before I read you couldn't do it. Now of course I wouldn't even try.;) I was much younger then too.Quote:
PS I've never heard of anyone handproping a 912 even though it has a gearbox. Anyone done it?
BTW, I've been living with my Rotax decission for 14 years and 2,500 plus hours of reliable, cost effective , fuel efficient, low maintenance very enjoyable flight. My engine decission worked out great. Hope yours does too.
I wouldn't even want to try hand-proping a 912. They say a minimum of 200 rpm to make the Ducati boxes fire. Besides with the style of charging system these motors use, you need some battery to make it charge. Running without a battery in the loop will ruin the rectifier/regulator.
I don't know how the Jabs work, but you can prop a 2-stroke Rotax. A member of our chapter has a 503 powered Ridge Runner and he always props it. Here it is being done by one of our own (DaveF) on a 582.
http://www.youtube.com/watch?v=W867v6beoo4
The batteries were not totally dead on the two I did it on but not enough charge to turn them through the compression stroke. Don't try it Larry, at our age we're both too slow to get out of the way if/when it starts now.;)
Did a complete tear down and inspection of my 912 ul with 1829 hours on the hobbs. The only component that measured out of spec was the gear box thrust washer. (old style brass washer) lots of lead build up. My only complaint from the engine is alittle rough running at certain r.p.m`s. My model 3 with a 912 and ivo inflight prop will out perform my friends speedster with a jabiru. The Jabiru sounds sweet, very smooth running. More of a simple engine.
Thanks Foxkit3 for getting back to the question. Just trying to get input on the jab pros and cons.;)
Chuck Lutgerote is completing a pressure cowl install on a Zenith 750 and has a lot of data on the cooling problem. I saw the pattern he is installing and he is anxious to see the summer heat test out his theory. The bottom line is, a lot of airflow goes right over the engine and never goes through the cooling fins. His fix should solve that problem. Give him a call.
He is on the Zenith Forum.
He's in Sandpoint Idaho.
Anyone heard anything about the heat issues on the Jabiru 3300 lately:confused:
I've been investigating putting on a Jabiru 2200 on my Kitfox IV project.
But because this is my first plane, and due to the fact that all 6 Kitfoxes flying in the Nehterlands are Rotax-equipped, I thought it might be wiser to stay with the familiar type and the experience that comes with it.
However, from that investigation time I learned that for any Jab it is very important to find a way to get hot air OUT of the cowling - in stead of getting more cool air IN.
Jabiru airplanes are equipped with a kind of 'lip-edge' at the underside of the air-outlet, to make under-pressure, and suck more air out of the cowling.
Given the massive air-inlet the 'older' (up to IV) Kitfoxes have with the round cowl, inlet should be no problem...
Hans,
I built a kitfox IV with a Jabiru 2200. I modified a Sky Fox cowl and installed it per advice from Dave J. From New York State. I have no issues cooling my engine even when it's the weather is warm. I now have over 70 hours logged flying. if you have any questions just let me know.
Dan G.
What is a "Skyfox" cowl?
I was informed Skyfox is the Austrailan version of Kitfox when I ordered the Firewall forward for the Jabiru 2200.
My brother and I built a series7 with a Jabiru 3300 engine. The only time we have high cylinder head temperatures are during climbs in 90 degree plus weather.We also replaced the Bing carb with an Aero Vee carb because we had problems with uneven air flow to the engine. We have more problems with high oil temperatures during cruise in hot weather. We have flown to Oshkosh two times and plan to fly the 1400 nautical miles to the Kitfox Flyin this September.