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New Jabiru Engine


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Yes it's easy to call for features and lose the total original concept in the process. The Jabiru developed of necessity when the original (italian?) engine became unavailable. The idea being Aircooled horizontally opposed flat four with direct drive. (Plenty of those around, including the recent UL which seems well built).

 

If the facts as stated are true one would think the company has gone well into it.

 

IF they are using vaccuum die casting (which gives a very accurate and a consistent result ( which gravity castings do not) I would imagine they would have to go overseas. Most aeroengines that are air cooled have the heads and cylinders more or lees in one piece to eliminate the troublesome cylinder head joint. This makes it a lot harder to service the motor without specialised equipment

 

IF you were going to go liquid cooled it would pay to go for an engine where the "block" is one piece for strength and rigidity. A la Subaru which still has detachable heads and tends to be heavy and more complex. The currently available liquid cooled non jabiru heads may take care of head temps but do not overcome the problem of uneven temperatures in the steel cylinder barrell that Rotax does not experience because it is aluminium just like the ones being proposed to be used on the Jabiru. Nev

 

 

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IF they are using vaccuum die casting (which gives a very accurate and a consistent result ( which gravity castings do not) I would imagine they would have to go overseas. Nev

The castings looked very neat and clean not unlike the Rotax so hopefully it is a vacuum die casting. Even the tappet cover is a casting, and yes, it is all done overseas and I'm told, is cheaper to produce than the present chrome molly steel cylinders. Regards, Bob

 

 

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Tomo, you'd have to be careful of crosswinds WALKING to the plane!!

That's true, but being skinny is a plus in that situation, as you just turn so the air goes past! 019_victory.gif.9945f53ce9c13eedd961005fe1daf6d2.gif

 

 

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Given the lack of testing and development in the past I wouldn't touch any 'new' Jabiru development till some other mug has put 1000 hrs on it. Normally you would expect an engine manufacturer to do that sort of testing themselves but we all know that Jabiru's test program is carried out by the folk who buy their engines. The same folk that regret it later.

 

The dog of an engine I bought needs much work and money spending on it before it will be reliable enough to fly any great distance. So far 38 hrs and stripped and new parts already.

 

Stand well back from this new equipment until you have evidence of many hundreds of hours of testing...... or rue the day you stood in line to join the test program.

 

Regards, Clive

 

3300 #1460

 

2200 # 596

 

(70kgs)

 

 

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I quite understand Clive J's point-of-view. I am in the "unofficial/un-paid test-pilot" stage with my second-incarnation 2.2l Jabiru engine. To beat the first incarnation it merely has to do 675 hours without breaking through-bolts, burning out exhaust-valves, leaking oil like an blown-out oil-well, or cracking the base of a rear cylinder. My first Rotax 582 lasted longer and was still running sweetly when it went for a rebuild!

 

Personal opinion follows:-

 

If Jabiru abandoned making engines and just fitted Rotax 912/914 engines, they'd have to open another factory just to keep up with the demand for airframes. They wouldn't be able to make them fast enough, and within three years they'd have ten thousand airframes being hauled around by the little Austrian "engine that could" instead of the little Australian "engine that couldn't".

 

 

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Just a thought.Wouldnt Jabiru be better off trying to sort out the reliability issues with their current designs. Instead of building another engine? It is hard to have much faith in them, when just about every month there is another engine reported to have failed at low hours.Eg=this months Sportpilots Magazine. Cant blame maintenance when the engine failed at a whopping 8 hours TT since new.

 

 

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We don't know why most of these engines failed. Jabiru can't oversee every installation and there are so many variables in how they are used. Valve springs should not fail at low hours. Supply source? Nev.

 

 

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We don't know why most of these engines failed. Jabiru can't oversee every installation and there are so many variables in how they are used. Valve springs should not fail at low hours. Supply source? Nev.

It would have to be wouldnt it Nev ?I dont think in this case it was the installer.The only thing I can think of, is a dodgy valve spring.

 

 

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The valve springs have to be of the highest quality. They will stop your engine . Remember Terry's AERO valve springs? The Continental valves have 3 springs fitted, so maybe there is some redundancy. They probably do it for tension.

 

Funny, you can build cars where they will go a million K's in cabs and never break a valve spring. Nev

 

 

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VW, built, probably the most number of cars (aircooled) Chevrolet built a Corvair, (Also used in homebuilts) and there were plenty of others. Honda Toyota NSU Trabant ( eastern block peoples car (2-stroke,) Citroen Deux chevaux (spelling?) Dyna Panhard. An American 6 cylinder with a Hickory Chassis and alloy panels in the 20's the name of which eludes me at the moment. There would be lots more. Many war tanks in WW2 were aircooled, usually with ab aircraft related radial installed and many eastern block rail cars also. Nev

 

 

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Given the lack of testing and development in the past I wouldn't touch any 'new' Jabiru development till some other mug has put 1000 hrs on it. Normally you would expect an engine manufacturer to do that sort of testing themselves but we all know that Jabiru's test program is carried out by the folk who buy their engines. The same folk that regret it later.The dog of an engine I bought needs much work and money spending on it before it will be reliable enough to fly any great distance. So far 38 hrs and stripped and new parts already.

 

Stand well back from this new equipment until you have evidence of many hundreds of hours of testing...... or rue the day you stood in line to join the test program.

 

Regards, Clive

 

3300 #1460

 

2200 # 596

 

(70kgs)

Clive

Just for the record , was your 38 hour engine new or rebuilt ,what were the problems leading to the new parts ,was it a 4 or 6 cyl and was it run on Avgas or Mogas

 

Bob

 

 

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Hi Bob, 38 hrs from new.

 

The engine was blowing a bit of oil but I took the heads off because of the lack of compression on 3 oo 6 cylinders, leakdown was 13, 73, 16, 76, 17, 58 or something like that. Actually I didn't need a leak down you could tell by hand winding. I found that the valves weren't seating well, they were sort of varnished where that should have been shiny as they weren't seating. I put this down to the hydraulic tappets being 'over pumped'. A shame as I don't have what one would say we great oil pressure.

 

Whilst I had the heads off I noticed what I thought was wear on the valve guides. However after they were measured it could be seen that it was a manufacturing fault as all 12 were the same size, all 12 valves rattling away. In fact it was predicted by the ex Jab engineer who was going to fit the new guides for me as he'd seen it before.

 

I since I have read of quite a few folk believing they have excessive guide wear and I suggest they too may have had the same problem as me. Just they never found out as early as I did so they put it down to actual wear. Had I not lost compression and investigated how would I have known.....when a dropped a valve maybe?

 

So I'm flying again now and watching the compression to see what develops.

 

Regards, Clive

 

 

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I wouldn't have called it mass produced but I guess they are. They stuck with the aircooled engine and with it in the back too, (where it shouldn't be really), for a long while. A good collectable, with "presence".

 

The early porsche engine (model 356?) is a developed Volkswagen and was used as an industrial engine too. Each exhaust valve is angled, whereas the VW 's are parallel . You could buy them new in the 50's. That is probaly the one in the KR-2. Nev

 

 

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concerning different carb set ups for Jabiru take a look at what sonex are doing with their installations, they claim to have much better fuel distribution with even temps. Their carbs are reasonable price too, be worthwhile for someone to give it a run. Tom

 

 

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Claiming ot have" better" fuel distribution is a big call. A lot of people claim a lot of things. Most of the distribution (even ness) is to do with the shape and length of the manifold sections and is an extremely difficult job to get right unless you have one carb to each cylinder ( as in the 2-s 582 Rotax). Better atomisation helps, but modern "car" fuels are not good in this respect. Nev

 

 

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