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zodiac3813

Firewall forward kit for Jabiru/Rotax 912

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Looks like a nice conversion, beautifully done.The cost of conversion is a pretty big factor though.

 

I do have issues with info that 100hp can be faster and maintain climb performance without IFA prop especially with 600kg.

 

jetjr: Haven't you realised they are magic, well at least in some eyes anyway.

 

I have lost count of the number of aircraft that fly faster and burn less fuel then the POH in the opinion of some of their owners. Then when I fly them they come back around the POH figures - obviously must be me being the only common factor.

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Nev, I was talking ground adjustable for the 3300, plenty of them around

 

 

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The safest is laminated two blade wood .That's where I would stay. When you get up to 12o knots airspeed you are getting into C/S territory. Its just that I like a certified prop/ engine combo with C/S particularly. Most people I have seen playing with ground adjusted props end up fitting the original or something like it, back on.

 

The wood prop is easiest on the engine. Nev

 

 

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Fair enough, large percentage Jabirus now with composite ground adjustable. Its the standard factory option now I think.

 

We arent dealing with certified models Id guess.

 

I wouldnt go back to Jab wooden version even if they were free. Constant balancing, tracking and rubbish performance. I went through 3 in ~200hrs.

 

Engine stress is a big deal for sure and like temp needs monitoring and optimization, dynamic balancing needs wider implementation. Also maybe guidelines for pitching prop and engine loads

 

Static rpm is a crude way to measure load and its different for different prop materials. Only one reference I've found to MAP and pitching Jab prop.

 

Not sure why this isnt used more to determine suitable load limits in relation to pitch?

 

 

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Fair enough, large percentage Jabirus now with composite ground adjustable. Its the standard factory option now I think.We arent dealing with certified models Id guess.

 

I wouldnt go back to Jab wooden version even if they were free. Constant balancing, tracking and rubbish performance. I went through 3 in ~200hrs.

 

Engine stress is a big deal for sure and like temp needs monitoring and optimization, dynamic balancing needs wider implementation. Also maybe guidelines for pitching prop and engine loads

 

Static rpm is a crude way to measure load and its different for different prop materials. Only one reference I've found to MAP and pitching Jab prop.

 

Not sure why this isnt used more to determine suitable load limits in relation to pitch?

There are wooden props and wooden props. My Alpi has a Brent Thompson prop that is very smooth, never needs balancing or tracking, and performs as well as the Alpis with C/S Idrovario props. Ground roll is a little longer, but once in the air, climb rate is close to 1000 ft/min - 2-up. Cruise is 100kts at 4750 rpm. It just needs the occasional retorquing. Also, I use 3 litres p/hr less fuel than the C/S units. I am aware of a number of Jabiru owners who have fitted one of his props and they have found that performance has improved, both climb and cruise.

 

 

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Meanwhile, back at the 'Firewall forward' thread, there is a Rotax Service agent, with manufacturing capability, that has done one conversion with another coming.This was a J230 fitted with a standard 912ULs and 3 blade Sensenich ground adjustable prop.

Depending on pitch setting, cruise speed is similar or could be a little faster, but the real improvement is awesome climb rate and about 15% better fuel economy.

 

Wasn't game to ask the conversion price, but the customer was quite happy.

 

[ATTACH=full]38853[/ATTACH]

Care to mention who the rotax service agent is?

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Care to mention who the rotax service agent is?

At the moment he is very busy with his primary business, and is doing another conversion (Limbach to 912) which, despite the cost to the owners, don't make him much (if any) money.

When he thinks he can get to do it practically, he will no doubt advertise.

 

 

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A 100 hp rotax may put out as much thrust or more than the 120hp jab probably mainly due to a larger more efficient prop turning slower. Just quessing at the reason for the good performance in the jab airframe.

 

 

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It was available recently "6 months or so) and on this site by link. I don't have the link.( Oscar may) Explained the history and the reasoning. The Jabiru motor is very light weight, and they didn't want to be dependent on another engine manufacturer, like they were with the KFM. Nev

Another factor is exchange rate. Rotax is European. Over the past 10 years the exchange rate has fluctuated from 0.45AU$ to 0.85AU$ for one €. Almost a factor of two. It's now at 0.63AU$ to 1€. That makes a steady business model very hard to do.

 

 

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