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  #1  
Old 10-21-2012, 03:57 PM
Lucky Clover Lucky Clover is offline
 
Join Date: Sep 2012
Location: Portales, NM
Posts: 7
Default Jabiru 3300 RV-3

Just ordered my rv3 kit. Will mostly be using it for cross country trips. The jabiru is 120hp but is much lighter than the other suggested engines. Will I have to worry about my cg?
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  #2  
Old 10-21-2012, 04:33 PM
gasman gasman is offline
 
Join Date: Mar 2007
Location: Sonoma County
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Quote:
Originally Posted by Lucky Clover View Post
Just ordered my rv3 kit. Will mostly be using it for cross country trips. The jabiru is 120hp but is much lighter than the other suggested engines. Will I have to worry about my cg?
Yes. So why don't you just use an 150 Lyc?
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  #3  
Old 10-21-2012, 04:35 PM
Lucky Clover Lucky Clover is offline
 
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Location: Portales, NM
Posts: 7
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Having to build on tight budget. Can get a new jabiru with fwf for $24000
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  #4  
Old 10-21-2012, 04:46 PM
Alschief Alschief is offline
 
Join Date: Jan 2005
Location: Anderson MO
Posts: 440
Default RV3 FWD

Suggest you give the UL Power a look
It is a fine power plant.
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  #5  
Old 10-21-2012, 04:48 PM
David Paule David Paule is offline
 
Join Date: Dec 2009
Location: Boulder, CO
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You can get a used Lycoming for less....

I flew behind a Jabiru 3300 recently and was impressed by it. The only part I didn't like was its Aerovee carb. Can't see any reason to have one of those. But the engine was smooth and powerful, light and small. Started instantly.

It's roughly 80 to 100 pounds lighter than the Lycomings, and that's bound to introduce some CG issues. If you move the engine forward, you're moving the prop forward and that reduces stability. It's not exactly a slam dunk. But if you can bring it off, you'll find a number of people interested in it.

Dave
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  #6  
Old 10-21-2012, 05:08 PM
Lucky Clover Lucky Clover is offline
 
Join Date: Sep 2012
Location: Portales, NM
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The jabiru is highly supported and easily installed. Have been looking over the rv3 layout. Considering the ways to move the cg forward without having to relocate the engine forward.
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  #7  
Old 10-21-2012, 06:16 PM
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N941WR N941WR is offline
 
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Location: SC
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Quote:
Originally Posted by Lucky Clover View Post
...Will I have to worry about my cg?
Yes but since you will need a custom engine mount anyway, have it made longer
Your bigger issue will be controlling the high CHT's the Jabirus are becoming known for.
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  #8  
Old 10-21-2012, 06:37 PM
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rph142 rph142 is offline
 
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Location: Walnut Creek CA
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Moving the cg forward wont be too tough. If I were you I would extend the .032 front side skins, floor, and top skin. You have to cut all of these pieces to size anyway, so it won't take any longer to cut them longer.
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  #9  
Old 10-21-2012, 07:50 PM
cubdriver cubdriver is offline
 
Join Date: Sep 2009
Location: San Diego
Posts: 148
Smile Engine Choice

If you want to build light, you might consider Lycoming's new o-233 116 HP engine. It is a great engine, should solve CG issues and can use a factory supported engine mou t from Vans. I have one in an RV9 and it works great. Plane is light and nimble.
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  #10  
Old 10-22-2012, 12:23 AM
highflight42x highflight42x is offline
 
Join Date: Aug 2011
Location: Pasco
Posts: 107
Default RV3 CG w/Jabiru engine

There would be a *severe* cg problem in a standard RV3 with an engine 80-100lbs lighter than a Lycoming.

With such an engine, the engine mount will need to be re-designed and the fwd fuselage possibly extended. Either way, you'll have a very different structure fwd of the cockpit, implying some serious structural analysis and design work. The flight characteristics could change drastically - the farther fwd the engine, the more different the inertial characteristics will be.

This engine will require an entirely new cooling solution, new cowling, baffling, fuel and exhaust systems. These secondary tasks alone will be quite expensive. Is there a propeller for the Jabiru with the pitch/diameter needed for the RV3's speed envelope?

In short, to install an engine that the aircraft was not designed for, you will become a true experimenter. I'm not trying to persuade you not to do this, just be aware that with a new untried engine installation, it will cost much more than you originally intend, and will take 2x (or more) time to do it.

good luck!

- Steven
RV3 builder/pilot
(700+ RV3 hours)
(... 1.5 more today!)
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