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MichaelGibbs(at)cox.net Guest
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Posted: Sun Jul 02, 2006 1:11 am Post subject: 912s vs. Jabiru 3300 |
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Quote: | But the Rotax has the problems often talked about on our site.
Thrown carbs, shaking start, cracks and stuff. It just makes me
think the Jabber is a bit better.
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Anyone following the light sport category developments of the last
few years will note that the Rotax 912 and 912S dominate the field.
There are also certified aircraft (such as the Diamond Katana) flying
behind certified versions of the 912. There must be a reason they
are so popular with manufacturers.
I am no expert on the Jabirus but from what I have heard from members
of the Desert Fox Squadron, the 4-stroke Rotax engines are lighter,
produce more thrust, and burn less fuel. Murle Williams told me
today of a couple of friends of his that had 912-powered 'foxes that
flew with a Jabiru-powered 'fox of the same model and configuration
on a cross country trip. The Rotax-powered planes had to slow down
by about 10 mph for the Jabiru to keep up and when they landed, the
latter took on significantly more fuel.
There is no perfect solution to any problem, and the 912 family is
not perfect either. But the problems mentioned above all have
solutions and I'm sure the 3300 has problems as well.
As for me, my last 'fox had a 912S and the next one will as well. My
Model IV-1200 with Ivo medium prop could launch in 120 feet (solo),
sustain a 40 degree climb angle, hit Vne (140 mph) in level flight,
and sipped gas like it was something expensive...wait...I guess it
is. Empty weight came in at 660 pounds.
Quote: | I simply want to have a few more ponies than 100 so I can get a bit
more cruise out of the airplane...
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Additional horsepower is not what you need to increase your cruise
speed, it's additional thrust. More horsepower MIGHT give you more
thrust but it depends upon a lot of other factors as well.
As with all opinions, this one is worth what you paid for it.
Mike G.
N728KF
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Michel

Joined: 10 Jan 2006 Posts: 966 Location: Norway
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Posted: Sun Jul 02, 2006 2:15 am Post subject: 912s vs. Jabiru 3300 |
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On Jul 2, 2006, at 11:09 AM, Michael Gibbs wrote:
Quote: | from what I have heard from members of the Desert Fox Squadron, the
4-stroke Rotax engines are lighter, produce more thrust, and burn less
fuel.
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I don't know, Mike, since I never had a 912 but I think it would be
strange that a Rotax, with its gearbox and water cooling system is
lighter than a Jabiru. My fuel consumption at cruise speed (Kitfox 3)
is about 12 liters per hour. How does that compare to a 80 HP Rotax?
Here is an interesting link from UK:
http://www.sportair.co.uk/cgi-bin/Page87L2.htm
Cheers,
Michel
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_________________ Kitfox 3 - Jabiru 2200 |
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darinh
Joined: 20 Apr 2006 Posts: 327 Location: Utah
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Posted: Sun Jul 02, 2006 12:04 pm Post subject: Re: 912s vs. Jabiru 3300 |
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Michel,
My last Fox (Model III like yours) had the 80 hp 912 and it burned right around what you are getting with the 2200...about 3-3.5 gph at 75%.
Mike,
I understand that it is thrust that give you speed but as you said this is dependent on a whole lot more than your engine's power. It depends very much on the prop as well. That is why I am trying to figure out if the Jabiru is compatible with an in-flight adjustable prop. If so, I would think that you could get very good use out of the extra 20 hp by adjusting the prop and hence getting a bit more speed out of the airplane. I appreciate your input and as stated, have no problems with the 912 (I have owned one and loved it and will most likely go with another for this kit) I simply want to explore my options and I figure you guys can help me make and informed decision.
Can anyone out there give me some real life data on a Series 7 with a 912S and an IFA prop? What kind of cruise do you see?...How about climb rates? Keep in mind that I am in Utah (4500' msl) so the sea level data doesn't mean much to me. I would like to find someone who has flown in and out of say...the Idaho backcountry with the setup mentioned. Anybody got any numbers...?
Thanks,
Darin
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smokey_bear_40220(at)yaho Guest
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Posted: Sun Jul 02, 2006 12:37 pm Post subject: 912s vs. Jabiru 3300 |
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Darin,
You sure know how to stir things up. People here
marry their engines like they do their planes.
Luckily you didn't ask which was better, a Fox or a
Rans.
Someone here has a 3300 on a Fox, but I forgot who.
I am not an owner of either engine choice, so I hope
impartial.
John McBean sells some inflight adjustables props and
has some good data on them, if he is around and has
the time to share. I think he has been flying with
them himself.
I think it is the weight and stiffness or resonance of
the prop that is the issue with the Jabbers. The
first engines had cranks that were too light for some
of the props people tried. I think that was fixed,
but a light weight prop is still required.
You have the extra HP from the 3300, even with the
greater fixed pitch prop loss. If you can use an
adjustable, it should be a great performer. Closer to
a 914 at much less price and repair costs.
The Roo 3300 is certainly a simpler installation to
work on, assuming you can remove the ducting easily.
Kurt S. S-5/NSI turbo/CAP
--- darinh <gerns25(at)netscape.net> wrote:
Quote: | Michel,
My last Fox (Model III like yours) had the 80 hp 912
and it burned right around what you are getting with
the 2200...about 3-3.5 gph at 75%.
Mike,
I understand that it is thrust that give you speed
but as you said this is dependent on a whole lot
more than your engine's power. It depends very much
on the prop as well. That is why I am trying to
figure out if the Jabiru is compatible with an
in-flight adjustable prop. If so, I would think
that you could get very good use out of the extra 20
hp by adjusting the prop and hence getting a bit
more speed out of the airplane. I appreciate your
input and as stated, have no problems with the 912
(I have owned one and loved it and will most likely
go with another for this kit) I simply want to
explore my options and I figure you guys can help me
make and informed decision.
Can anyone out there give me some real life data on
a Series 7 with a 912S and an IFA prop? What kind
of cruise do you see?...How about climb rates? Keep
in mind that I am in Utah (4500' msl) so the sea
level data doesn't mean much to me. I would like to
find someone who has flown in and out of say...the
Idaho backcountry with the setup mentioned. Anybody
got any numbers...?
Thanks,
Darin
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smokey_bear_40220(at)yaho Guest
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Posted: Sun Jul 02, 2006 12:38 pm Post subject: 912s vs. Jabiru 3300 |
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Michel,
--- Michel Verheughe <michel(at)online.no> wrote:
..............
Good link and story. I do think the engines are
almost equal and you have to go with the little
preferences, or less price.
Kurt S.
__________________________________________________
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darinh
Joined: 20 Apr 2006 Posts: 327 Location: Utah
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Posted: Sun Jul 02, 2006 5:46 pm Post subject: Re: 912s vs. Jabiru 3300 |
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smokey_bear_40220(at)yaho wrote: | Darin,
You sure know how to stir things up. People here
marry their engines like they do their planes.
Luckily you didn't ask which was better, a Fox or a
Rans.  |
I guess they do but I wouldn't be so ignorant to ask such a thing as which was better a Fox or a Rans...the answer is obvious isn't it? ...I love the Rotax...just looking at options.
Quote: |
You have the extra HP from the 3300, even with the
greater fixed pitch prop loss. If you can use an
adjustable, it should be a great performer. Closer to
a 914 at much less price and repair costs. |
That would be exactly what I am looking for! Just don't know if it is compatible with the IFA props. I will talk to Jabiru tomorrow.
Darin
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MichaelGibbs(at)cox.net Guest
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Posted: Mon Jul 03, 2006 1:25 pm Post subject: 912s vs. Jabiru 3300 |
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Darin sez:
Quote: | Can anyone out there give me some real life data on a Series 7 with
a 912S and an IFA prop? What kind of cruise do you see?...How about
climb rates?
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I have reams of such data, but they are from my Model IV-1200. Let
me know if you'd like me to look it up for you.
Mike
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