Rotax vs. Jabiru

[Cal Vanize]

As I continue to research, the Zodiac XL and the Sonex are on the short
list. Both offer a couple of engine options including Rotax 912
(variations) and the Jabiru 3300. Real-world performance doesn't seem
like it would be that much different, at least on paper.

I hope this isn't a religious issue. I'm interested in opinions on both
the Rotax and Jabiru options.

TIA.

[Cal Vanize]

Cal Vanize wrote:

>
> As I continue to research, the Zodiac XL and the Sonex are on the short
> list. Both offer a couple of engine options including Rotax 912
> (variations) and the Jabiru 3300. Real-world performance doesn't seem
> like it would be that much different, at least on paper.
>
> I hope this isn't a religious issue. I'm interested in opinions on both
> the Rotax and Jabiru options.
>
> TIA.


Or if I opt for a Zodiac XL, would it be better to use a Conti O-200?

[Morgans]

"Cal Vanize" > wrote
>
> Or if I opt for a Zodiac XL, would it be better to use a Conti O-200?


I think it pushes it above the weight for LSA designation. Check on that.
--
Jim in NC

[Morgans]

"Cal Vanize" > wrote
>
> I hope this isn't a religious issue. I'm interested in opinions on both
> the Rotax and Jabiru options.

More people are badmouthing Jubiru, than are badmouthing the Rotax 4
strokes.

YMMV.
--
Jim in NC

[[email protected]]

I've only got 120 trouble free hours on my 912ULS, so I'm no first hand
expert, but, the 912 was recently changed from TBO of 1200 hours to
1500. That seems like a fairly good endorsement for reasonablely good
field experience.
tom

[News]

wrote:
> I've only got 120 trouble free hours on my 912ULS, so I'm no first hand
> expert, but, the 912 was recently changed from TBO of 1200 hours to
> 1500. That seems like a fairly good endorsement for reasonablely good
> field experience.
> tom
>
For the best first hand info check the clasifieds in Australia and see
the story

Jabiru 3300 6 cyl. Engine 125 hrs, core engine and all accessories, no
top end. $3000 Ph 02 9688 2011or 0417 218 299


Jabiru 2200, Factory rebuilt 1999. Only 46hrs engine (total airframe
hours 164).


Aircraft for Sale Jabiru, factory built TT 1150 hrs, Engine TT 150hrs, Long


JABIRU 2.2Lt 55-0735 factory built, TT 750 hrs, Engine 150 hrs. Latest
Head Mod. Spats,


JABIRU 2.2 Factory Built, 55-936, LAME Condition Report 24/3/05, latest
2.2, oil cooler kit Engine TT 392, airframe TT 1072


Jabiru LSA 55-0727. Just love the rego! Approx 1100 airframe and 220 on
latest 2.2 engine.


JABIRU, factory built, 2.2engine and propellor 170 hrs, airframe 1034hrs,


This tells you that at best you will get 300 to 1000 hours from an
engine designed and promoted as 2000 hr tbo END OF STORY

[ET]

Cal Vanize > wrote in
:

>
> As I continue to research, the Zodiac XL and the Sonex are on the
> short list. Both offer a couple of engine options including Rotax 912
> (variations) and the Jabiru 3300. Real-world performance doesn't seem
> like it would be that much different, at least on paper.
>
> I hope this isn't a religious issue. I'm interested in opinions on
> both the Rotax and Jabiru options.
>
> TIA.
>
>

Sonex does not offer support or FWF for the Rotex,... Just the Jabiru
(120 or 80hp) or Sonex' own "AeroVee" 80HP Volkswagan-based engine.
There are also several flying with GP VW conversions, and a couple with
a corvair (over the recomended FWF wieght though)

Both the Sonex and Zodiac are terrific planes with simular construction
methods. The Sonex is smaller both outside and in the cockpit, but
faster. The Sonex is at LEAST as fast as the factory claims (cruise
about 140-150 on 80hp, and 150-165 w/ jab 3300 (mph) yes they both meet
LSA limits since "max continuous power @ sea level is still under 138))
the Zodiac has never lived up to the factory speed claims (just ask or
read history on the Matronics list for confirmation). That doesn't make
the 601xl a bad plane, far from it... Just something else to throw into
the mix while considering.

If you havent already, join the yahoo SonexTalk list (
<http://groups.yahoo.com/group/sonextalk/> ) and the Zodiac list on
Matronics (<http://www.matronics.com/Navigator/?Zenith-List>).

I chose the Sonex, mostly because of speed and the fact that I am
building from scratch, and the full size planse from Sonex are much more
detailed & sutable for scratch building. If I was building from a kit,
I might still be scratching my head....






--
-- ET >:-)

"A common mistake people make when trying to design something
completely foolproof is to underestimate the ingenuity of complete
fools."---- Douglas Adams

[UltraJohn]

Morgans wrote:

>
> "Cal Vanize" > wrote
>>
>> Or if I opt for a Zodiac XL, would it be better to use a Conti O-200?
>
>
> I think it pushes it above the weight for LSA designation. Check on that.
Jim
I'm not sure if your talking about the 'built' version or E/AB version.
If it's the experimental version you can set the gross weight where you
like. Just limit it to the LSA requirement and your good to go. You will
lose some useful load which you can trade off with smaller tanks and less
range if you need the weight.
John

[Montblack]

("UltraJohn" wrote)
> I'm not sure if your talking about the 'built' version or E/AB version.
> If it's the experimental version you can set the gross weight where you
> like. Just limit it to the LSA requirement and your good to go. You will
> lose some useful load which you can trade off with smaller tanks and less
> range if you need the weight.


Could you ex"pound" on this - set the gross weight where you like?

Thanks


Mont ....blue, yeah, that's it - Montblue

[ET]

"Montblack" > wrote in
:

> ("UltraJohn" wrote)
>> I'm not sure if your talking about the 'built' version or E/AB
>> version. If it's the experimental version you can set the gross
>> weight where you like. Just limit it to the LSA requirement and your
>> good to go. You will lose some useful load which you can trade off
>> with smaller tanks and less range if you need the weight.
>
>
> Could you ex"pound" on this - set the gross weight where you like?
>
> Thanks
>
>
> Mont ....blue, yeah, that's it - Montblue
>


As the builder/manufacturer of an ambuilt-experimental you can
absolutely set the max gross weight anywhere you like... Who is to tell
you that a kit that others have built and set at, say 1450lbs is
mandatory for you to do the same.... Of course, a ramp check when you
and your 200lb friend climb out and pull out pull out 200Lbs of camping
gear that's 150lbs over your gross weight will be a problem....

S-LSA and kit E-LSA are regulated as to the min usefull load to combat
just this issue... but ambuilt expermimental is not.
--
-- ET >:-)

"A common mistake people make when trying to design something
completely foolproof is to underestimate the ingenuity of complete
fools."---- Douglas Adams

[Montblack]

("ET" wrote)
> S-LSA and kit E-LSA are regulated as to the min usefull load to combat
> just this issue... but ambuilt expermimental is not.


Can a SP built, then fly an ambuilt experimental? I declare it to be
.......1,320 max gross?

I declare it to fly ...138 mph continuous max power, etc. I declare it to
have a stall speed of...


Montblack

[ET]

"Montblack" > wrote in
:

> ("ET" wrote)
>> S-LSA and kit E-LSA are regulated as to the min usefull load to
>> combat just this issue... but ambuilt expermimental is not.
>
>
> Can a SP built, then fly an ambuilt experimental? I declare it to be
> ......1,320 max gross?
>
> I declare it to fly ...138 mph continuous max power, etc. I declare it
> to have a stall speed of...
>
>
> Montblack
>
>

Simple answer, yes....

You don't "declare" it, per-se, but durring your phase one testing you
establish these numbers and enter them in your POH for phase II flying.

If your off a little... probably no problem.. if your "off" alot..
probably no good will come of it.....

--
-- ET >:-)

"A common mistake people make when trying to design something
completely foolproof is to underestimate the ingenuity of complete
fools."---- Douglas Adams

[Nils Rostedt]

"News" wrote
>>
> For the best first hand info check the clasifieds in Australia and see the
> story
>
The Rotax 912 has had about 10 years head start on the Jabiru to achieve
reliability. It had its share of gremlins in the beginning (ignition box,
stator assembly, rocker arms) but AFAIK nowadays they are quite reliable.
I'd recommend the gearbox slipper clutch option, as it removes the need for
a teardown after a propstrike.

I understand Jabiru has been working hard to fix the bugs they too had in
the earlier engines, but have no closer experience. I would also think
things get better as the experience grows how to install and operate the
engine. Might be a good idea to research how the newer engines perform.

[UltraJohn]

Montblack wrote:

> ("UltraJohn" wrote)
>> I'm not sure if your talking about the 'built' version or E/AB version.
>> If it's the experimental version you can set the gross weight where you
>> like. Just limit it to the LSA requirement and your good to go. You will
>> lose some useful load which you can trade off with smaller tanks and less
>> range if you need the weight.
>
>
> Could you ex"pound" on this - set the gross weight where you like?
>
> Thanks
>
>
> Mont ....blue, yeah, that's it - Montblue
Yes Montred (hey if you can do it I can) ;-)

You can set the gross weight for E/AB where you like. You might/should have
some documentation as to what the pane can actually maxout but you
certainly can set it lower for safety sake.
The speeds are another story. You can't easily 'set' the max continous etc
etc but you could put an electronic (or otherwise) limiter on the engine to
keep the speed within limits and/or adjust the prop pitch/diameter to limit
airplane (or prop/engine) speed. Now if you have a 250 kt plane it might be
difficult to limit it! My plane which I'm slowly (very slowly) working on
original specs are 180 mph cruise (yeah right) realistic most cruise at
140-150 so proping it down with a climb prop takes care of it easily the
problem is stall speed mines about 3 mph high so I need mods to lower the
stall down.
The whole point is E/AB has a lot of leeway!

Also the AMD CH601XL is SLSA (the one Jim Pellien is selling is ELSA)and it
has a Cont O-200 they lost 70lb useful load because of the engine weight
but it still has the 1320lb gross.

John

Sorry for the rambling post!

[Morgans]

"UltraJohn" > wrote
>
> Also the AMD CH601XL is SLSA (the one Jim Pellien is selling is ELSA)and
> it
> has a Cont O-200 they lost 70lb useful load because of the engine weight
> but it still has the 1320lb gross.

What is the useful load expected to finish out at?
--
Jim in NC

[jc]

Nils Rostedt wrote:

<snip>
>
> I understand Jabiru has been working hard to fix the bugs they too had in
> the earlier engines, but have no closer experience. I would also think
> things get better as the experience grows how to install and operate the
> engine. Might be a good idea to research how the newer engines perform.

Have looked at this issue fairly closely (before ordering a J160).

Verbally - the maintenance/failure issues have essentially ceased in the
past couple of years. This is from school operators as well as private
owners.

Records - Comparing the incident/accident records in the last couple of
years show a much lower rate of engine problems compared to say 5 years
ago. This is with a lot more jabs around.

It seems with a/c engines as with everything else they can be tested
thoroughly in extreme ways and come up shining. Once they are put in the
hand of the great unwashed anything can and does happen.

--

regards

jc

LEGAL - I don't believe what I wrote and neither should you. Sobriety and/or
sanity of the author is not guaranteed

EMAIL - and are not valid email
addresses. news2x at perentie is valid for a while.

[Ian Donaldson]

G'day

I live in Australia where that jabiru engines are manufactured, and I went
through the same dilemma regarding the choice of a 912 or a Jabiru engine
for my Murphy Rebel.

At our airfield there are maybe 30 Jabiru engines in service and there has
been a continual litany of broken valves, leaking head gaskets, faulty
ignition coils, rings sticking and bores glazing (etc), And that does not
include the tedious valve adjustments! To be fair, the factory seems to seem
to have got their new engines sorted, but I always feel that they are doing
field tests by using their customers as guinea pigs!

What swung me to the 100hp Rotax was that it is a well sorted engine with a
reliable history. There are a number of these in service here that have
3000+ hours on them. That was good enough for me. One downside to the Rotax
is the maze of hoses needed to connect the cooling system, but you can't
have everything.

I would strongly recommend that anyone who is contemplating using a Rotax is
to get the slipper clutch option. I recently fitted on to my engine and the
difference it made to the smoothness of the engine was truly amazing.


regards

Ian


> The Rotax 912 has had about 10 years head start on the Jabiru to achieve
> reliability. It had its share of gremlins in the beginning (ignition box,
> stator assembly, rocker arms) but AFAIK nowadays they are quite reliable.
> I'd recommend the gearbox slipper clutch option, as it removes the need
> for a teardown after a propstrike.
>
> I understand Jabiru has been working hard to fix the bugs they too had in
> the earlier engines, but have no closer experience. I would also think
> things get better as the experience grows how to install and operate the
> engine. Might be a good idea to research how the newer engines perform.
>
>

[[email protected]]

Another data point for Rotax engines comes from the fact that the air
force uses them in some of the drones vehicles. Google UAV and Rotax.
Draw your own conclusion on whether USAF endorsement is good or bad.
tom

[Ron Wanttaja]

On 13 Jan 2006 16:32:35 -0800, " > wrote:

> Another data point for Rotax engines comes from the fact that the air
> force uses them in some of the drones vehicles. Google UAV and Rotax.
> Draw your own conclusion on whether USAF endorsement is good or bad.

Not necessarily a powerful endorsement. The engines have full-time,
professional maintenance technicians and are cheap enough that the government
could replace them after a few flights. There's a lot of difference between a
few dozen hours on an unmanned vehicle on a military maintenance schedule vs.
thousands of hours on a non-professionally-maintained aircraft with a pilot
aboard.

Ron Wanttaja

[Morgans]

"Richard Riley" > wrote

> It had an engine that I thought - at first glance -
> would make a terrific Ultralight engine. 4 stroke, about 50 lbs and
> 50 HP. Then I found out that it had a TBO of 55 hours.

If it ran at 35 or 40 HP, what would the TBO be? If it were 200 hours, it
still might be a good ultralight engine.
--
Jim in NC

[Richard Lamb]

Morgans wrote:
>
> "Ron Wanttaja" > wrote
>
>> Not necessarily a powerful endorsement. The engines have full-time,
>> professional maintenance technicians and are cheap enough that the
>> government
>> could replace them after a few flights.
>
>
> Plus the fact that if one of them packs it in while in flight, they say,
> "no big deal, We have more aircraft in the storage depot. They didn't
> cost me anything."
>
> > There's a lot of difference between a
>
>> few dozen hours on an unmanned vehicle on a military maintenance
>> schedule vs.
>> thousands of hours on a non-professionally-maintained aircraft with a
>> pilot
>> aboard.
>
>
> Add to that the fact that that many of the drones only have a life of a
> few dozen hours. They shoot some of them down, even. They are all
> expendable.


Which would logically put us right back on the ground again, ;(

But the engines are generally built to last more than a few dozen hours.

And if they are shooting them up, there are probably a lot of them -
somewhere...

This has been the dream of aviators since the Wrights (and before!)

a LIGHT(!) weight, powerful engine, that will compliment the aircraft's
mission specifications.

I got to play with a Garrett engine on a crop dusters this summer.
LIGHT weight and POWERful took on new meanings...
-=wow=-


I thought this was an interesting set-up: 90 hp turbine in a Zodiac...
http://www.zenithair.com/misc/turbine-power.html
pic 4?

[Richard Lamb]

Richard Riley wrote:
> On Fri, 13 Jan 2006 18:45:32 -0800, Ron Wanttaja
> > wrote:
>
> :On 13 Jan 2006 16:32:35 -0800, " > wrote:
> :
> :> Another data point for Rotax engines comes from the fact that the air
> :> force uses them in some of the drones vehicles. Google UAV and Rotax.
> :> Draw your own conclusion on whether USAF endorsement is good or bad.
> :
> :Not necessarily a powerful endorsement. The engines have full-time,
> :professional maintenance technicians and are cheap enough that the government
> :could replace them after a few flights. There's a lot of difference between a
> :few dozen hours on an unmanned vehicle on a military maintenance schedule vs.
> :thousands of hours on a non-professionally-maintained aircraft with a pilot
> :aboard.
>
> Aint that the truth.
>
> A few months ago I was working on a proposal for a UAV program. We
> were going to use a UAV airframe that was well proven and put some new
> systems in it. It had an engine that I thought - at first glance -
> would make a terrific Ultralight engine. 4 stroke, about 50 lbs and
> 50 HP. Then I found out that it had a TBO of 55 hours.


For Real, Richard?

What a heartbreak.

[Richard Lamb]

Richard Riley wrote:
> :> A few months ago I was working on a proposal for a UAV program. We
> :> were going to use a UAV airframe that was well proven and put some new
> :> systems in it. It had an engine that I thought - at first glance -
> :> would make a terrific Ultralight engine. 4 stroke, about 50 lbs and
> :> 50 HP. Then I found out that it had a TBO of 55 hours.
> :
> :
> :For Real, Richard?
> :
> :What a heartbreak.
>
> For Real, Richard
>
> http://www.uavenginesltd.co.uk/index.php?id=402

THAT is the perfect UL motor tho.


Thanks for sharing.


Richard

[[email protected]]

The rotary engine site is pretty interesting. Back in school my
automotive engineering professor sort of ragged on the rotaries for
various reasons, including higher fuel consumption. It is interesting
that the rotaries on that website run 0.50 to 0.55 bsfc. This isn't
great for a gasoline four stroke engine, but compared to a two stroke
ultra light engine, it would be very nice.
tom

[Jim Carriere]

wrote:
> The rotary engine site is pretty interesting. Back in school my
> automotive engineering professor sort of ragged on the rotaries for
> various reasons, including higher fuel consumption. It is interesting
> that the rotaries on that website run 0.50 to 0.55 bsfc. This isn't
> great for a gasoline four stroke engine, but compared to a two stroke
> ultra light engine, it would be very nice.

0.5-0.55 is not bad for a small gas turbine either.

Sort of an apples to oranges to tomatoes comparison. Food for thought.

[Anthony W]

Jim Carriere wrote:
> wrote:
>
>> The rotary engine site is pretty interesting. Back in school my
>> automotive engineering professor sort of ragged on the rotaries for
>> various reasons, including higher fuel consumption. It is interesting
>> that the rotaries on that website run 0.50 to 0.55 bsfc. This isn't
>> great for a gasoline four stroke engine, but compared to a two stroke
>> ultra light engine, it would be very nice.
>
>
> 0.5-0.55 is not bad for a small gas turbine either.
>
> Sort of an apples to oranges to tomatoes comparison. Food for thought.


Only their 2 smaller air cooled rotary engines have the 50 hours TBO and
one 120 HP twin rotor is certified for manned flight in Europe. In any
case, I'd bet they're bloody expensive...

Tony

[Lou]

Where did you find the TBO?
I looked at the website for the 95 hp's and didn't see this.
Maybe right in front of me but I'm missing it.
Also, anyone see prices?

[Cal Vanize]

Lou wrote:
> Where did you find the TBO?
> I looked at the website for the 95 hp's and didn't see this.
> Maybe right in front of me but I'm missing it.
> Also, anyone see prices?
>

TBO in Zodiac engine option Rotax page:

http://www.zenithair.com/kit-data/zac-rtx912s.html

Price is ~ USD14,000 for the basic engine.


Doesn't look like the Rotax is on the recommended "short list" from
Zenith anymore. Or at least they don't seem to sell it direct opting
for Jabiru, Conti or Lycoming instead.

[Lou]

Dummy me,
I was refering to the UAV engines.

[Big John]

Richard

Was there anything listed for the reason for the 55 hours?

Big John
`````````````````````````````````````````````````` ``````````````

On Fri, 13 Jan 2006 19:13:05 -0800, Richard Riley
> wrote:

>On Fri, 13 Jan 2006 18:45:32 -0800, Ron Wanttaja
> wrote:
>
>:On 13 Jan 2006 16:32:35 -0800, " > wrote:
>:
>:> Another data point for Rotax engines comes from the fact that the air
>:> force uses them in some of the drones vehicles. Google UAV and Rotax.
>:> Draw your own conclusion on whether USAF endorsement is good or bad.
>:
>:Not necessarily a powerful endorsement. The engines have full-time,
>:professional maintenance technicians and are cheap enough that the government
>:could replace them after a few flights. There's a lot of difference between a
>:few dozen hours on an unmanned vehicle on a military maintenance schedule vs.
>:thousands of hours on a non-professionally-maintained aircraft with a pilot
>:aboard.
>
>Aint that the truth.
>
>A few months ago I was working on a proposal for a UAV program. We
>were going to use a UAV airframe that was well proven and put some new
>systems in it. It had an engine that I thought - at first glance -
>would make a terrific Ultralight engine. 4 stroke, about 50 lbs and
>50 HP. Then I found out that it had a TBO of 55 hours.

[Mike Gaskins]

I don't have any experience with the Jabiru at all (heck I still
haven't completed my checkride ;)), but just a few things to be aware
of:

1. Rotax is water cooled; Jabiru is air cooled. Don't know if this
matters to you, but I thought I'd mention it.
2. Rotax runs at a very high engine RPM and uses a redrive to lower the
RPM at the prop level. I know this it is something that you could get
used to, but the 1 time I flew in a Rotax powered plane it sounded like
I was about to blow the engine, even when it was well below redline.
3. At equivalent power levels, Jabiru seems to a smidgeon cheaper.
4. Jabiru seems to have a lot of FWF packages available for different
aircraft already designed and ready to go.

Personally, though I haven't done a lot of research, I'd personally
look more at the Jabiru. Definately don't take