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-   -   Jabiru RV-12 Update (http://www.vansairforce.com/community/showthread.php?t=66354)

KatieB 02-02-2011 05:56 PM

Overhaul costs are about $1200/cylinder if we do the work here in Shelbyville. We also recommend a top overhaul (pistons, rings, valves) at 1000 hours, which costs about $600/cyl.

They do perform very well at altitude. When I go cross-country in my 3300-powered J230 demonstrator, it's 2850 rpm and 118-122 knots true at really anything under 10,000 feet. You can maintain 2850 rpm all the way up past 10,000 feet.

In case people are wondering, the prop diameter of the 3300-powered J230 is 60", and I never see anything close to 3300 rpm redline unless I push it over into a fast power dive. Cruise is a nice and easy 28-2850 rpm. On takeoff you'll see about 2850 rpm.

I don't know anything about Rotax engines, other than what they sound like.

rv6ejguy 02-02-2011 06:00 PM

I don't have a stake in this race as I sell EFI systems for both the 912 and Jabiru engines.

You can apply to join the Yahoo Jabiru Group : http://groups.yahoo.com/group/jabiruengines/ if you want unbiased first hand experience with these engines. You can read the archived posts until you get very tired but it is certainly not all roses.

When the engines first came out, they were pretty terrible and went through several redesigns especially with heads and a lot of extra finning added. There have been numerous issues over the years and Jabiru has slowly come out with fixes to most of them. Many people have experienced loosening head bolts even on the later engines. How much is due to poor baffling on the owners part is open to discussion. Rotec now offers liquid cooled heads for these engines so some feel the latest design changes don't fix all the issues. http://www.youtube.com/watch?v=Li9LiDYGQOQ

Many people seem to experience mild problems with high EGTs and CHTs and other problems related to the carb and poor mixture distribution.
Others have reported valvetrain issues. Yet others say the engines work great and seem to have few issues.

Granted some of these are with older engines and some may be caused by operator error or poor maintenance just as people who ignored recommendations by Rotax had problems with 912s and tended to badmouth them.

Many people feel that the latest engines are quite good if you do a proper installation and proper maintenance, others feel even the latest engines are unlikely to make TBO without some work along the way. I say education is good so read the group posts and decide for yourselves.

Just remember than Van could have chosen the Jabiru for the RV12 but did not. Rotax has many times more 912 engines flying and many times more flight hours than the Jabiru. They've had their troubles in the past too but have a good reputation now, they are just very expensive. Frankly I don't see any power to weight advantage with the Jabiru and it seems the 2200 is too small and the 3300 too big for the RV12.

Just my 2 cents for whatever it's worth. There is nothing wrong with offering an alternative to the 912 for those who want a direct drive, air cooled engine and I wish everyone the best enjoying their -12s with whatever engine they choose.

rv6ejguy 02-02-2011 06:10 PM

Quote:

Originally Posted by Dirtbos (Post 509972)
I was scoffed at in another thread when I tried to explain this, but the Jabiru 3300 (as I have read) performs better at altitude than the Rotax. The Rotax apparently is just about maxed out throttle travel wise at sea level where the 3300 is not. Sonex claims 170 mph true at altitude (a bit optimistic from what I understand) as it is able to maintain fairly good rpm at altitude. Of course that is up for debate :D .

All naturally aspirated engines lose power in direct proportion to air density as you climb in altitude. The 3300 engine is rated at 20 more hp than the 912S and it would maintain this hp advantage at any altitude. It is bigger and heavier so not strictly comparable. Kind of like saying a 540 in an RV-X performs better at altitude than a 360.

Dirtbos 02-02-2011 06:17 PM

Quote:

Originally Posted by rv6ejguy (Post 509990)
All naturally aspirated engines lose power in direct proportion to air density as you climb in altitude. The 3300 engine is rated at 20 more hp than the 912S and it would maintain this hp advantage at any altitude. It is bigger and heavier so not strictly comparable. Kind of like saying a 540 in an RV-X performs better at altitude than a 360.

Then end result is the only thing that is important. There is not a whole lot of difference between the 912 and the 3300 as far as installed weight is concerned. If and when Jabiru USA (or someone else) is able to put together an RV-12/3300 combo, then we will know. If it produces better climb and cruise (if that is the most important to those that chose the combination) then that is all that matters. Time will tell.

Driftdown 02-02-2011 06:56 PM

What's the difference in weight between the Rotax 912ULS and the Jabiru 3300?

Jetguy 02-02-2011 07:32 PM

Lets compare apples to apples!
 
On the 12 we use a 70 in prop. I think I could achieve similar high power setting at altitude with a 60 in prop on the rotax.:p

rv6ejguy 02-02-2011 07:36 PM

Quote:

Originally Posted by Dirtbos (Post 509992)
Then end result is the only thing that is important. There is not a whole lot of difference between the 912 and the 3300 as far as installed weight is concerned. If and when Jabiru USA (or someone else) is able to put together an RV-12/3300 combo, then we will know. If it produces better climb and cruise (if that is the most important to those that chose the combination) then that is all that matters. Time will tell.

The 2200 Jab will be slightly lighter and not go as fast or climb as well as the 912S, the 3300 will weigh more, go faster and climb better. It's all about hp as far as performance is concerned.

Jetguy 02-02-2011 07:41 PM

Pump it up!
 
But how will adding 40 lbs to the nose of the 12 affect it?

rv6ejguy 02-02-2011 07:44 PM

Quote:

Originally Posted by Driftdown (Post 510005)
What's the difference in weight between the Rotax 912ULS and the Jabiru 3300?

The 912ULS weighs just under 150 lbs. complete with airbox, exhaust, starter etc. and coolant. The 3300 weighs just under 180 lbs. in the same trim. The 2200 weighs 132-138 depending on the source. These figures from the manufacturers.

I weighed the 912 we did testing on and the figures seem accurate.

Jetguy 02-02-2011 07:56 PM

In the spirit of debate!
 
Not to sound picky just adding to the fun debate while trapped in house during winter wonder land out side. We don't use a air box on the 12. Also for a comparison for katie when you weigh the nose when you are all done mine weigh 147lbs.:rolleyes:

Peterk 02-02-2011 08:21 PM

Speed?
 
the 3300 will weigh more, go faster and climb better.

I guess I'm kinda mystified why anyone would be interested in building an LSA category aircraft and be concerned about going faster? Speed is not a design mission by LSA developers. Weight is for sure because it decides how much you can carry. Fuel efficiency is because it decides how long you can fly. Poor efficiency and you pay with fuel weight. As a rule, speed doesn't help fuel efficiency either. The use of Bing carbs (Rotax and Jabs) do not maximize fuel efficiency. At altitude both will reveal awful EGT's. Ross (RV6ejguy) has developed beautiful injection systems to replace both...at reasonable prices. I'm certain that Rotax and Jabiru both are satisfied with Bing since they both produce much better fuel burn than most American counterparts. To inject them would make a great product even better (always has). Better would mean more weight available and that's a worthy goal.

rv6ejguy 02-02-2011 08:34 PM

Quote:

Originally Posted by Jetguy (Post 510030)
Not to sound picky just adding to the fun debate while trapped in house during winter wonder land out side. We don't use a air box on the 12. Also for a comparison for katie when you weigh the nose when you are all done mine weigh 147lbs.:rolleyes:

The airbox weighs just under 3 lbs. but rumor is that you lose a few hp by removing it.

rv6ejguy 02-02-2011 08:45 PM

Quote:

Originally Posted by Peterk (Post 510036)
the 3300 will weigh more, go faster and climb better.

I guess I'm kinda mystified why anyone would be interested in building an LSA category aircraft and be concerned about going faster? Speed is not a design mission by LSA developers. Weight is for sure because it decides how much you can carry. Fuel efficiency is because it decides how long you can fly. Poor efficiency and you pay with fuel weight. As a rule, speed doesn't help fuel efficiency either. The use of Bing carbs (Rotax and Jabs) do not maximize fuel efficiency. At altitude both will reveal awful EGT's. Ross (RV6ejguy) has developed beautiful injection systems to replace both...at reasonable prices. I'm certain that Rotax and Jabiru both are satisfied with Bing since they both produce much better fuel burn than most American counterparts. To inject them would be make a great product even better (always has). Better would mean more weight available and that's a worthy goal.

Higher engine weight reduces the useful load as I well know with my conversion but by using a 27 lb. prop, weight on the nosewheel is similar to Lycoming powered RVs with CS props and the C of G is similar as well. 30 lbs. or so up front with an already light prop on a -12 may require other solutions.

I'm not on here trying to sell anything but I do like to see people informed about the pros and cons of engine swaps. I also believe you should fly the engine of your choice after weighing (excuse the pun) the plus and minus points. If you don't fancy water cooled, high revving, geared engines, the Jabiru gives you another choice. If you end up not liking the Bing carb, there are other solutions.:)

DonFromTX 02-02-2011 08:49 PM

To help you get over being mystified, some of us are old guys who used to have medicals and liked to go places far away in planes. Now we can't have our 200 mph four place planes any longer, but we still appreciate getting there faster. I quite agree with your post, and especially agree that a good fuel injection system on that Rotax would be a wonderful thing.

Quote:

Originally Posted by Peterk (Post 510036)
the 3300 will weigh more, go faster and climb better.

I guess I'm kinda mystified why anyone would be interested in building an LSA category aircraft and be concerned about going faster? Speed is not a design mission by LSA developers. Weight is for sure because it decides how much you can carry. Fuel efficiency is because it decides how long you can fly. Poor efficiency and you pay with fuel weight. As a rule, speed doesn't help fuel efficiency either. The use of Bing carbs (Rotax and Jabs) do not maximize fuel efficiency. At altitude both will reveal awful EGT's. Ross (RV6ejguy) has developed beautiful injection systems to replace both...at reasonable prices. I'm certain that Rotax and Jabiru both are satisfied with Bing since they both produce much better fuel burn than most American counterparts. To inject them would be make a great product even better (always has). Better would mean more weight available and that's a worthy goal.


Peterk 02-02-2011 09:15 PM

Don
 
Well now that you put it that way...lol...I'm not mystified. Sounds like you need to be thinking about turbocharging, oxygen and a nice jet stream! All that aside I will be stunned if you don't fall in love with your 12 in spite of all the Barons etc we've all flown.

Pete (North Texas/Home of the Ice Queen)

Dirtbos 02-02-2011 10:55 PM

Quote:

Originally Posted by Peterk (Post 510036)
the 3300 will weigh more, go faster and climb better.

I guess I'm kinda mystified why anyone would be interested in building an LSA category aircraft and be concerned about going faster? Speed is not a design mission by LSA developers.

I have a private pilots license with a current medical. Just looking for an easy build, storage off airport, reasonable operation costs, etc..

KatieB 02-03-2011 11:35 AM

Additional Info...
 
Jabiru USA has been supporting Jabiru engines for builders of Zenith, Sonex, Kitfox, Rans, Titan, and others here in the U.S. for nearly 13 years. We are homebuilders ourselves-- Mostly RV-builders, with a Jabiru-powered Zenith, a Pitts and a Skybolt thrown in for variety. (We build composite LSAs for work-- Gotta do something different at home!)

No engine is indestructible-they require maintenance like any other aircraft engine. They need fresh high-octane fuel, periodic checks of head bolt torque (a simple task performed at each 50-hr oil change), and no unauthorized fuel or oil additives. Early solid-lifter engines also required valve adjustment. They got a bad rap early on because the early cooling ducts and cowl openings were too small to handle the 6-cylinder engine. That problem has been fixed for several years now in firewall-forward kits that we offer. Most people like them for their simplicity, reliability, economy, and sound.

For technical info, you can read the manuals online: http://www.jabiru.net.au/

DonFromTX 02-03-2011 11:43 AM

But Katie, you forgot SMOOTHNESS of the 3300!
I was aware of cooling problems pervious owners had, mostly Sonex. Nice to know that problem has been pinned down and cured.

KatieB 02-03-2011 12:05 PM

Thanks, Don-- Can't forget about the smoothness! :D

Here's what we did yesterday, if anyone is interested:

http://picasaweb.google.com/lh/photo...eat=directlink

szicree 02-03-2011 12:18 PM

No offense, but...
 
that thing looks so tiny! My only experience has been with a Superior 360 and by comparison that deal looks miniature. My next build will likely have a Rotax so I guess I need to get used to the look of small.

Sam Buchanan 02-03-2011 12:56 PM

Quote:

Originally Posted by KatieB (Post 510251)
Thanks, Don-- Can't forget about the smoothness! :D

Here's what we did yesterday, if anyone is interested:

http://picasaweb.google.com/lh/photo...eat=directlink

Does Possum look at you like that all the time??????

Looks almost like he has his Sunday overhauls on. ;)

diamond 02-03-2011 01:22 PM

Quote:

Originally Posted by KatieB (Post 510229)
... Most people like them for their simplicity, reliability, economy, and sound. ...

What about the sound? How does it compare to the Rotax? What about volume in the cockpit? More, less or the same as Rotax? I rode in a 12 a while back and although I loved everything about it, it was rather loud, I thought.

KatieB 02-03-2011 01:46 PM

sound
 
Quote:

Originally Posted by diamond (Post 510288)
What about the sound? How does it compare to the Rotax? What about volume in the cockpit? More, less or the same as Rotax? I rode in a 12 a while back and although I loved everything about it, it was rather loud, I thought.

If you go to our Facebook page here http://www.facebook.com/pages/Jabiru...=search&v=wall

scroll down the page, and on the left side you'll see a video called "S-19 Victory Pass." That's the 6-cyl. The 4-cyl 2200 is similar, but not so meaty...

I've only flown behind a Rotax a few times, so I can't really compare the in-cockpit sound. The airframe has a lot to do with it-- I know in a low wing composite Lightning, you can talk to someone next to you with no headset on while the 3300 is at cruise power, but that's a tightly sealed airplane. The main difference is that you don't have a gearbox in the Jab, and your'e running at an engine RPM more than a Lycoming but much less than a Rotax. I think it sounds sort of Cirrus-like.

Yes Sam, I get that Possum look quite often!!

splitty 02-03-2011 08:56 PM

Cyld. Heads
 
As Ross mentioned earlier Rotec( Australia) have developed a water cooled head assembly for the Jabiru Egine which in tests so far have proved excellent as here In Hot Oz when have some huge Ground & Air temps which have caused some Headaches & Probs. these replacement heads are still under development & Testing But may well prove to bullett proof the Engine.:)

Jetguy 02-03-2011 09:55 PM

Wow!
 
Water cooled heads man what a concept!:eek:

Ok ok I was just kidding I coudnt resist.:rolleyes:
Please forgive me for the low blow.:D

Peterk 02-03-2011 10:37 PM

Cabin noise
 
Katie...they all sound like a Cirrus with a set of Zulu's. You should throw those in with your engine package...lol

KatieB 02-04-2011 09:09 AM

Quote:

Originally Posted by Peterk (Post 510425)
Katie...they all sound like a Cirrus with a set of Zulu's. You should throw those in with your engine package...lol

OK, ya got me there. ;) They spoil me here occasionally.

How's this: According to the Jabiru Australia website (www.jabiru.net.au), the 2200 has been measured at 62 dB in a 1000' AGL full-power flyover. This was in a Jabiru aircraft equipped with the stock stainless muffler.

Peterk 02-04-2011 09:47 AM

Quietness
 
My 912ULS is so quiet....when I do flybys I have to honk to get people off the runway! lol

KatieB 02-04-2011 11:10 AM

I've read that many places over in Europe they have strict dB requirements for aircraft, so the 912 should be quiet. It's more of a quality difference... ;-)

Danny7 02-04-2011 11:27 AM

Katie do you check your PM's?

DonFromTX 02-04-2011 12:51 PM

Thats nothing, mine is so quiet - I have to look at the tach to see if it is still running!:)

Quote:

Originally Posted by Peterk (Post 510502)
My 912ULS is so quiet....when I do flybys I have to honk to get people off the runway! lol


KatieB 02-04-2011 01:17 PM

Yep--
 
Quote:

Originally Posted by Danny7 (Post 510538)
Katie do you check your PM's?

Sent you an email on your Hotmail acct a few days ago... and just sent you another PM with more info.

Danny7 02-04-2011 06:17 PM

oops, sorry i never got anything it might have been filtered out. first time that has happened in along time...
but i got your PM, thanks. sent an email on to the guy you recommended

KatieB 02-04-2011 06:37 PM

No problem, spam filters suck sometimes!

KatieB 02-16-2011 11:50 AM

Update
 
Figured it was time for another update. The wings are almost skinned...

https://picasaweb.google.com/katie.b...eat=directlink

and the cowl is still being shaped in Wisconsin. When the fuselage comes back in a week or two, it will be the start of an interesting time as the guys figure out the best placement of accessories on the firewall.

Stay tuned!! :D

Peterk 02-16-2011 12:02 PM

Cowl
 
Interesting. How did they decide the cowl shape without accessorizing the engine? There's a lot of big stuff...radiator, muffler, oil can etc. Just curious.

KatieB 02-16-2011 02:02 PM

The guys hung the engine and attached the muffler, tail pipe and fiberglass cooling ducts at the cowl shop. They also mounted the spinner onto the prop flange so they can use it to shape the nose bowl. The biggest pain turned out to be the starter cable-- they put a spacer on top of that to give it adequate clearance. The mags and and starter are already in place on the engine and the alternator is built into the flywheel assembly. We'd like to keep the chin area clean so the oil cooler will be mounted inside the cowl similar to the Arion Lightning. The battery box, airbox, fuel pump, cabin heat box, gascolator, etc (and I"m sure there are other things I'm forgetting) go on the firewall. There's no oil can or radiator to worry about on the Jab. ;)

krazydoc33 02-17-2011 11:06 PM

Oil pressure sensor location
 
I recently downloaded the Skyview installation documants just in case Vans does approve the Skyview in place of the Flight Deck. Dynon are quite clear that the sensor should NOT be mounted on the engine. They prefer a remote location for the sensor. On the engine or some place else? Not much room for comprise.
Henry
NM, RV-12
Quote:

Originally Posted by lucien (Post 503578)
One of my 912 mechanics says all the time that the only true enemy of the Rotax is its owner/operator. And I think he's exactly right about that since, when left alone and installed/operated the way Rotax specifies, it gives no trouble. Also, the 912 series is NOT new technology anymore; in fact, it's one of the highest selling engines of all time now and has one of the best reliability records you can find in an aircraft engine.

So, all that said, there's nothing wrong with the location of the oil pressure sensor as-is - the engine will go to TBO and beyond giving no trouble with the sensor right where it is, so I'd suggest leaving it alone for reliability and long life and following the manuals to the letter.

I would also suggest that Vans knew what they were doing when they made the few alterations to the motor that they have, so it's probably a good idea to give their methods a chance before substituting them for you own.

Not an RV12 builder, just a very satisfied long-term Rotax user,

LS


Peterk 02-18-2011 09:08 AM

Oil Sensor
 
Like others, I have moved my sensor to the firewall...an easy mod and it certainly has no effect on the engine itself. The reason I did was because the beginning location is next to the gearbox and your oil pressure readings on the Dynon jump all over the place...most likely due to vibration. After I moved it, the readings stay rock-solid.

Peterk 02-18-2011 09:11 AM

Cowling
 
Quote:

Originally Posted by KatieB (Post 514217)
The guys hung the engine and attached the muffler, tail pipe and fiberglass cooling ducts at the cowl shop. They also mounted the spinner onto the prop flange so they can use it to shape the nose bowl. The biggest pain turned out to be the starter cable-- they put a spacer on top of that to give it adequate clearance. The mags and and starter are already in place on the engine and the alternator is built into the flywheel assembly. We'd like to keep the chin area clean so the oil cooler will be mounted inside the cowl similar to the Arion Lightning. The battery box, airbox, fuel pump, cabin heat box, gascolator, etc (and I"m sure there are other things I'm forgetting) go on the firewall. There's no oil can or radiator to worry about on the Jab. ;)

Katie, any chance they put any "structure" into the cowling to allow for quarter turns instead of hinges? Maybe a weight issue, maybe not

Pete


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