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Jabiru option for RV-12?

F

freegespeed

Active Member
I hope the cowl for the RV12 fits the Jabiru 3300 motor. I would prefer the direct drive, air cooled Aussie engine, over the high priced and finicky(low TBO) Rotax 912S motor.

Anyone heard if Vans is being flexible about his LSA engine options?

I currently own a RV6A, but with the price of fuel and a few other variables thrown in, it's making me think about this model.

Cheers
 
J3300 vs 912s

Both engines have issues.

The 912S is very different from most aircraft engines - combination air / liquid cooling, dual carbs with automatic mixture adjustment, CDI, etc. You're going to have a harder time finding A&Ps who want to work on it if you have an S-LSA. If it's experimental, then no issue - you just need metric tools ;)

I'm not sure that the J3300 is better on maintenance. IIRC, valve adjustment is every 25 hours. The 912S has maintenance intervals of 50 hr (oil change only) and 100 hr. TBO is 1500 hr for new 912S.

I do have a feeling that if you run 100LL all the time that the J3300 will be better over the long haul. The 912S uses a common oil system to lube engine and PSRU. A Lockwood aviation tech told me that during overhaul, it takes him 2 seconds to tell how much 100LL an engine burns - lots of it turns up in the PSRU. Oil changes for 912S that burn lots of 100LL should be more like every 25 to 33 hr.

J3300 has more power, but has more vibration. 912S is more complex but has a MUCH longer operating history.

Either one will be good, but Van has said that the RV-12 will be setup for the 912S. Just like putting a TCM IO-240B in a RV-9 (makes more sense to me), you can do it, but it will be more work.
 
Hi Clark,

I believe you will find that the 912 has a longer TBO than the Jabiru, a lot less routine maintenance although Jabiru are supposed to be working on hydraulic lifters - but given its problems in the past with valves, heads etc, hyd lifters may well only hide the problems temporarily - and a much, much better service history, not to mention re-sale value.

As for fuel economy, swapping an RV6's 150 knot cruise using 6.5 - 7 US gallons an hour for the RV-12's 4.2 US gallons per hour fuel burn at 100 knots works out pretty much the same when touring, though flying around the patch favours the smaller engine, plus you can use unleaded auto fuel.

Cheers

Harvey
 
Thanks for the details about both engines

About three guys down here at Brown field are running Jabiru engines with some small issues but mostly with success. One fellow has a Wittman Tailwind varient in which he pulled out an 0-290 Lyco for a six cylinder Jabiru. He claims to have lost about 20 knots cruise speed down to about 120 kts. But he gained in fuel economy. Another gentleman has a Sonnix with a four cylinder Jab engine in it.

I think I may be a little prejudiced against the Rotax 912 due to the terrible TBO times on the Diamond Katana. With a light enough airframe the Rotax motors might just be fast enough and be able to climb. I flew in a Europa with a 914 in it a few years back, and it was very smooth and quiet. The owner pilot of the Europa said that idling and taxiing are hard on the engine from a heat control perspective.

I do like flying at 150 knots, and I can see what you're talking about on figuring out time and distance cost analysis, which probably means I won't be saving that much money on cross country flying. However those after work flights of less then one hour on the tach might be quite a bit cheaper since you're talking about time in the air and not particulaly distance flown.

Thanks for the tips. I plan on two more years with my RV6A and maybe by then the RV12 will be a reality.
 
912 has come a long way

freegespeed said:
I think I may be a little prejudiced against the Rotax 912 due to the terrible TBO times on the Diamond Katana. With a light enough airframe the Rotax motors might just be fast enough and be able to climb.
Click to expand...
The 912 certainly started out as a somewhat unattractive product - low TBO, lots of maintenance issues, etc. The 80Hp version didn't exactly light the Katana on fire (although the 100Hp variants are supposedly good), but did have very few in-flight engine failures.

The product has evolved significantly since then - 1500 hr TBO, 100Hp 912S version, reduced maintenance, better slipper clutch. The main problems, IMHO, are the price and low availability of maintenance. The first ain't gonna change, but the second will, particularly if Cessna builts its LSA with Rotax power.
 
will jabiru be an option -- realistically?

HI all,

I am new to building, very new, don't have a kit yet but I have the need! I want to see the RV-12, it sounds like my A/C, but I would really rather fly behind the Jabiru. I know many of you have built and modified your machines, modified them to fit your personal preferences. When Van's begins selling the kits, and the kit is designed with the rotax 912s in mind with the firewall design and all -- realisticaly, will the Jabiru 3300 be a viable option. I know with time and money you can do anything. But for a builder who really has no design capabilities, will there be suppliers with engine mounts, cowlings etc. that will allow me to use the Jabiru and not add years to my construction time? There will probably be a weight/balance issue, hopefully not too serious an issue! fFor those who haven't flown behind the Jabiru - it is a very impressive little engine. Your Rv-12 LSA with the Jab 3300 will be a fine pacakge. Ok -- JMHO -- what do you think about the Jabiru possibility? thanks---

ceuh1v
 
Depends.

If you are building the aircraft as an experimental aircraft, and you have a PPL, you are free to do whatever you want to the aircraft. As someone has pointed out, the recess in the firewall does not appear to be able to accommodate the Jabiru. But if you are more interested in re-engineering Van?s design than building/flying, the world is your canvas.

If however, you will be operating the aircraft in one of the LSA categories, and you will be exercising the privileges of a Sport Pilot, my reading of the regs is that you can not deviate from the manufacturers approved plans. The Aircraft are approved under a consensus standard, and only those aircraft that conform to the standard can be operated under the LSA rule.
 
RV6junkie said:
Depends.

If you are building the aircraft as an experimental aircraft, and you have a PPL, you are free to do whatever you want to the aircraft. As someone has pointed out, the recess in the firewall does not appear to be able to accommodate the Jabiru. But if you are more interested in re-engineering Van?s design than building/flying, the world is your canvas.
Click to expand...

True, if you build it as an Experimental then you can modify it to whatever engine you desire. Doesn't matter what type of license you have or don't have, you don't need a Pilots License to build an airplane.

RV6junkie said:
If however, you will be operating the aircraft in one of the LSA categories, and you will be exercising the privileges of a Sport Pilot, my reading of the regs is that you can not deviate from the manufacturers approved plans. The Aircraft are approved under a consensus standard, and only those aircraft that conform to the standard can be operated under the LSA rule.
Click to expand...

Not true, the aircraft will either qualify as an LSA or not. It can be Certified like a Cub, Experimental like a Sonex, Special-LSA (S-LSA) like a EuroFox or an Experimental-LSA (E-LSA) like a Quad City Challenger II although the Challenger II could be registered as Experimental as well and qualify as an LSA as well. Doesn't matter what license you have or what privileges you are exercising while flying it, the aircraft will either qualify as an LSA or not.

After you build your E-LSA eligible aircraft you can either register it as an Experimental or Experimental-LSA. There are advantages and disadvantages to both but the choice is yours.

Now what Gary is referring to is the S-LSA kit. That is where the manufacturer offers a kit that has more than 51% of the aircraft already done for you. Vans doesn't offer this now but has said that it is considering it in the future with the -12. With this option you would be required to complete the aircraft per the manufactures plans with no deviation allowed.

So, if experimenting is your game then don't buy a S-LSA. You would have to do more work but you are allowed to make any changes you would like.
 
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Dang it! I hate it when I'm only half right.

Poor Van, just can't win. He hasn't even test flown the aircraft yet and there are those who think he's made the wrong decision on engine choice.

From my own personal experience: When you call Van's help line for help, and you have done it their way, they give you all the time of the day. That makes difficut problems seem much less difficult. On the other hand, when you decide to modify the design with something that they have no experience with - call over - you're on your own (and for good reason).

Build it the way you want, but know that you might be on your own. I like building, but I found that inventing sure is a lot more work than I ever thought it might be. One thing always leads to another, which leads to another....
 
I'm beginning to think that if they threw in the engine for free, some still wouldn't like it. I don't have a problem with Rotax. There is plenty of support for them all over the world and the US. They are cheap to buy and maintain. With the way I fly and a lot of others, there is about 15 years worth of flying to be done before reaching TBO.

I also love the building process, mine will be about as standard as one can be built. Deviating from the plans can really add to the build time. Those that have the talent have my respect.
 
The RV-11 motor glider that Van is building in his garage is powered by a Jabiru so I would think that he has looked at the strengths and weaknesses of both engines. THe Jabiru for the RV-11 motor glider and the Rotax for the RV-12. Just love having all of these options.

Steve Eberhart
RV-7A, almost ready to flip the fuselage.

P.S. http://www.vansaircraft.com/public/rv-11int.htm
 
I knew you would know!

Thanks for your insight and keep the information coming! I am neither an engineer nor a sheet metal mechanic. I can, put my new gas BBQ together without having any parts left over! I have heard that to deviate from the plans causes much extra work, I believe it! So, if Vans has a Jabiru option then I would buy that engine, but if Rotax is the only factory engine offered, then Rotax it is. I hear that most drilling and deburring will be done when you get the kit, the holes will be punched to final size, just pop the rivets--I can do that! The Vansairforce is a great website and I know I can count on your help when I find myself in a difficult construction area. The final size holes is a rumor that I heard, don't quote me on that one.

Thanks
Jim
ceuh1v
 
Where there's a will there's a way

The anticipation of the RV12 will continue to give lively discussions like these here VAF. I personally feel that what ever needs to be done to accomodate the Jabiru motor to the RV12 can be accomplished with careful thought and persistance. A new cowl, a modified firewall, and a new CG range all look like fun challenges to me. I guess that's just being an expirimental builder, adapting and inovating to get the job done. It might take a little more time, but I can think of one reward right off the bat, qualifying for a tax break in California for having a,"one of a kind", aircraft. :)

Of course talk is cheap and theortical concepts are just thin air until somebody gets out and builds their vision into reality.

Also, it's very likely that Jabiru will make it's own firewall forward kit for the RV12 including a special cowl if need be.

Happy landings.
 
I'm still a little surprised that Van went with a liquid cooled engine, though the 912S is really a nice package. I'm sure we'll see some Jabiru's, and I agree that it would be a good choice. We might even see a single rotor Mazda :D

Cheers,
Rusty (no idea who would do something like that)
 
Why are you surprised that Van choose a LC engine? Obviously LC has many advantages over air cooling, including more consistent cylinder temperatures, the ability to run higher compression ratio?s, more efficiency, sleeker cowl designs (less drag) and less mechanical noise. The ability to run a higher compression ratio, with its resulting increase in horsepower, more than off-sets any weight penalty that the heat exchangers (radiators) and required plumbing bring to the installation.
 
There?s no difference between theory and practice.

In practice there is. (Yogi Berra)

With that out of the way I will share with you my personal experience with the 912S engines and Jabiru engines we fly in our Titan Tornado exp airplanes.

We have four 912S and 2 Jabiru 2200 powered planes in my area. My 912S Tornado just went over the 500 Hour mark with nothing but oil and spark plug changes. It does not use oil and looks as clean as the day it came out of the box. It uses Honda motorcycle oil, NGK auto plugs, and auto gas (100LL in x-country mode)

We have almost 3000 hours of total time accumulated in the four 912S engines in my area, all of them trouble free with only the aforementioned maintenance and the routine carb synch job needed with the dual carb set-up. That?s basically 3000 hours of $0 spent on failed parts operating 4 engines (some of us upgraded to a new hi-torque starter that came form the 80HP legacy so we spent some dough on upgrades).

I know of two operators that reached the earlier 1000 TBO in the 80HP version and Lockwood found them in good shape and declared them fit to continue flying without the need for new parts or machining work. That?s the sort of experience that pushed the TBO to the 1500 mark it currently has.

The two Jabiru airplanes had their share of issues. One is an early model and had the heads warp once due to heat stress and had to be resurfaced. One a different flight, one of the distributor shafts (Honda car part) galled away causing one side of the ignition to fail.

The other jabiru engine is about two years old and has failed twice in flight, the first one resulting in the aircraft destruction. The second one was a lubrication issue that gave the pilot enough time to make it back down safely and save the airplane (second one due to an improperly installed oil seal). The dealer took the engine with less than 150 hours on the clock back and replaced it with a new one.

It is noteworthy to say that both Jabiru engine owners experienced carb ice in moderate weather conditions, specially at idle during final or whilst taxing. Carb-DeIce is a must if you are going to use the Jabiru engine. Some guys are using electric heathers around the carb intake to alleviate the problem.

While many seem to complain over the liquid cooled engine, they do not realize the benefits that the 912S has over other non certificated engines:

1. Parts and EXPERT Service is available throughout the country
2. It has a certificated cousin in the lineage
3. Virtually carb-ice fool-proof
4. No Mixture adjustments needed
5. Free, SAFE, easy to get cabin heat
6. Constant temps, no shock cooling
7. Modern engine construction with close tolerances
8. Owner support through the Rotax owner website publishing SB?s and AD?s
9. Comprehensive repair manuals are available
10. Thousands of hours of operation experience
11. Gear box allows for less stress on the engine and deliver equal torque to the prop
12. Able to use composite propellers from many vendors
13. Able to use constant speed and in-flight variable pitch propellers
14. Vacuum pump and aux generator available
15. Thousands of engines flying world wide
16. Starts easily in the winter time here in Wisconsin (NO PREHEAT NEEDED)
17. Able to use synthetic oils

I personally think that Van?s decision on going the 912S route is a good one, especially with those of us that are familiar with the engine and have hundreds of hours operating one and realize how good an engine it is. On the other hand, that choice may not go very well with those GA pilots that seem to trust only Lycs and Conts and dismiss the Rotax/Jabiru/<name your engine here> brands.

I just completed a 1300 mile x-country trip in my 912S Tornado. It cruised at 100K sipping 5GPH and never had to monkey around with carb mix, worry about carb ice or add oil in the almost 14 hours I spent away from home. Heck, It has 50 hours since my last oil change and the oil level is right where it was 50 hours ago! It starts instantly and the temps remain constant all the times. Overall, I know at least 20 Rotax 912S owners and their experiences are similar to mine with only routine maintenance performed.

The grapevine tells the Jabiru 2200 has their teething problems fixed and is becoming a very reliable powerplant. Problem is you still have an engine that is air-cooled, needs pre-heat, suffers carb-ice, revs at too high-rpm, is limited to short wooden props, has only 2 service centers in the country and has virtually no factory support for SB?s and ADs.

While I am not crazy about the RV12 design (bland, uninspiring, and too Zenith/<insert Euro design name her> like looking), I think Van?s reputation alone will be worth a few hundred sales amongst those seeking an LSA airplane. The cost of fuel is making it more attractive now to use these 5GPH power plants and get more clock-time per dollar vs. miles per dollar, depending on whatever makes you click.

Spend a few a hours talking to Rotax 912 and 912S engine operators before you make a decision on whether a 912 engine is for you or not.

Jose Borja
Elk Mound, WI
 
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