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Jabiru Bad experience

Old 20th Jan 2014, 23:46
  #81 (permalink)  
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At what stage did I say I was using a "shandie"? lol


I have asked the factory about this on a previous occasion, they stated that its fine to top up on either fuel provided one or the other is the majority in the tank. Also I was told that it was to stop a trend that was developing, of people mixing 91ulp with avgas! had nothing to do with 98+.


When I say fuel up at other locations its a case of leaving 'home base' burning down to practical and topping up with the other until I get home.


To be clear the engine is out of warranty!
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Old 21st Jan 2014, 00:11
  #82 (permalink)  
 
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Wow..shandies now. What else can we come up with?
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Old 21st Jan 2014, 00:37
  #83 (permalink)  
 
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XXX the longer this goes on the more you sound like a factory rep. The guy has come on here to air his grievances about what appears to me to be a legitimate issue...not just for him but potentially all Jab drivers. It would seem that every scenario you have suggested has been adequately explained, now it just looks like you are the one pooh-poohing....just like Jab seem to be doing!
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Old 21st Jan 2014, 01:19
  #84 (permalink)  
 
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Hi all, long time watcher here.

I owned a Jabiru UL450, purchased it from the builder here in NZ.

Total engine hours are about 850, and has run perfect since day one. This is a 2200

Only issue I have had, is that uncommanded flap retraction, which was on very short finals, as soon as it happened, I applied full power and didn't hesitate to go around to check what was up and happening.

What caused that? Simple, just wear on the through bolt, quick tighten and check, and never happened again.
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Old 21st Jan 2014, 01:23
  #85 (permalink)  
 
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Deadstick

Just to clarify then.
1. Caltex 98 is fine, but it will increase CHT over Avgas (100MON or about 110RON) The shandi mix of 98/avgas is fine and I agree with the blocking 91UL/avgas.

2. The piston ring sticking with avgas is a known issue, should have been helped with the latter piston design with wider grooves not the std groove of a ULP auto engine. I have no idea how successful this was or is.

3. Seems CHT is a major contributor and I wonder just how well the cooling works around the whole area of the cylinder.

My opinions.....OK...these are WAG's but from a semi reasonable position to comment. Oil changes every 25 hours and not 50. Keep the indicated CHT (not necessarily the entire head) below 300 as there may well be parts that are much higher. Head torque checked every 25.

Climb speeds need to be nothing like the range of Vx or Vy and my suggestion is take Vy and x 1.32. Good reason for this, but not related to the topic but it will give you the climb sped I feel is likely to yield better results.

Email address is on its way. Probably not much more I can add here.

Recap gents,
the 230 suffered a cylinder head overheat on number 4 only no valve seat movement or valve failure, the subsequent bulk strip at the factory, revealed the bottom end was destroyed by the original inadequate thru bolt design.
How does a run away CHT relate to the bottom end being destroyed? Unless the rer was a destroyed piston and the debris went through the places wrecking everything else. Or magically the heat was channelled through one pot? Does not add up does it?
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Old 21st Jan 2014, 02:20
  #86 (permalink)  
 
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Jaba,

Oil changes every 25 hours and not 50...
Head torque checked every 25...
Surely in this age of technical expertise they can design a better engine than this?

I only ever flew Jabirus and other Ultralights for a very limited number of hours and could never feel at ease with the engine spinning above 5000 RPM. I realise they need this speed to produce the desired power output, and it's a case of chasing ones own tail regarding power vs weight.

Spend enough money and anything is possible.
Sorry for the link, couldn't get the Youtube link thingy to work?

https://www.youtube.com/watch?v=nsa6kq-qqIE

This video shows an operational cutaway of a BMW S1000RR a 193HP superbike bumping against its 14,200RPM redline. A cam and valvetrain at 118 cycles per second is an amazing sight (and sound)
Obviously not a suitable engine for an aircraft and probably has HUGE maintenance / reliability problems of it's own. However a pretty cool video to watch.
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Old 21st Jan 2014, 02:35
  #87 (permalink)  
 
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XXX the longer this goes on the more you sound like a factory rep. The guy has come on here to air his grievances about what appears to me to be a legitimate issue...not just for him but potentially all Jab drivers. It would seem that every scenario you have suggested has been adequately explained, now it just looks like you are the one pooh-poohing....just like Jab seem to be doing!
Nah I've got nothing to do with the factory; I'm happy with what has been eventually posted. First off was what looked like a one-sided grudge against Jabiru and their customer service. Now what we have with the quoted emails from Jabiru plus more information on the operation and history of the aircraft, readers are now able to make an informed decision for themselves and decide whether or not do deal with Jabiru or use their products in the future.

Those that haven't yet seen this might find it interesting:
New Camit Aero Engines | CamitAeroEngines
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Old 21st Jan 2014, 03:49
  #88 (permalink)  
 
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2 dogs. i dont think you flew a jab that revved at 5000 rpm. A rotax powered jab perhaps?
I agree though. We should have better engines avialable. I recall jabiru brought out a recommendation that the engines get a 25 hourly oil change. We immediately adopted this procedure IAW with factory directions. The 2200 engine was subject to this schedule at the time of the failure, and (at a guess) for the previous 100 hours leading up to it.
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Old 21st Jan 2014, 04:46
  #89 (permalink)  
 
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motzartmerv,

I do believe they were Rotax powered. Long time ago now.
I just remember the poor little things screaming and wondering how reliable they were. I saw the internals of a few and decided they looked a bit ...

There were some issues with the engines and the flying school eventually went Cessna.
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Old 21st Jan 2014, 04:55
  #90 (permalink)  
 
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Rotax reliability is now on par with the big bore cousins,Lycoming and continentals. i am just as confident behind a rotax as i am behind the IO540, even fly my own at cruise rpm of 5200rpm, keeping the revs higher keeps the internal pressures lower, runs smoother and never had a fault yet in just on 1000hrs behind it. i will fly behind jabs, and have flown them for quite some time, but i find myself a little more vigilant of potential landing areas when behind the jabiru.
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Old 21st Jan 2014, 05:09
  #91 (permalink)  
 
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Jabba
How does a run away CHT relate to the bottom end being destroyed?
It could be related as follows. From time to time when using nearly 100% unleaded (especially during long hot slow climbs) the peak pressure moved back to TDC thus exerting a greater than normal load on the bottom end and high heat loads on the top end. The engine was strong enough to cop this a few times but couldn't do it forever.A bit like a mistimed engine--sometimes you get away with it but for how long?

Eventually with maybe a bit of help from detonation the engine throws in the towel.The first cylinder to overheat detonated and the bottom end weakened with the through bolt issue and earlier unwitting abuse, fails.

This is not necessarily what happened but it is a possibility. I wonder how many failures of this type of have occured in engines which never use mogas.

Cheers RA
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Old 21st Jan 2014, 05:29
  #92 (permalink)  
 
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This is not necessarily what happened but it is a possibility. I wonder how many failures of this type of have occurred in engines which never use mogas.
if it was fuel/mogas related, then wouldn't we see the similar failures within the rotax fleet, which preferred fuel is Mogas. or is the situation avoided with the higher revs effectively moving peak pressures thurther from TDC? (which is why i run mine at 5200rpm)
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Old 21st Jan 2014, 05:41
  #93 (permalink)  
 
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The independent engine inspection report details that the bottom-end damage wasn't a result of the engine over-heating.

Perhaps DeadStick you can post that report on here too please for the likes of Jabba and others?
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Old 21st Jan 2014, 06:39
  #94 (permalink)  
 
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if it was fuel/mogas related, then wouldn't we see the similar failures within the rotax fleet,
Not if the Rotax timing is set up for Mogas .Then adding Avgas has the same effect as slightly retarding the timing which isn't hard on the engine unlike advancing the timing which is very hard on them.
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Old 21st Jan 2014, 07:05
  #95 (permalink)  
 
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More importantly, the annomoly would show up in the num,bers. There is no evidence to suport EITHER fuel being more or less "unreliable" in jab engines that im aware of. If 98 octane was causing issues, then im sure we would be onto it by now., The fact is there seems to be no common denominator. We have looked, hard. The only real thing we have noticed, is that blokes who do NOT follow the advice from Jab seem to have a better time. I dont mean that in a nasty way, its an observation.
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Old 21st Jan 2014, 07:29
  #96 (permalink)  
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XXX,
Just sent the full PDF with pics to Jaba
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Old 21st Jan 2014, 07:37
  #97 (permalink)  
 
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Two dogs,

Do not confuse me with the factory, but my comments were just an opinion in this case, and stated as such, that with a very small sump Qty, leaded fuel and high f/a ratios that more often would be prudent. In fact Rotax recommend this is using leaded fuel. As for head torque, sure they could design a better method, like a TCM/LYC design, but it is not.

RA....that is a long bow to draw as you say, but yeah I can see it is possible. I doubt the C98 or BP98 would be enough of a change in thetaPP and the timing is fixed, but what else? Again how would we know. Not enough data or evidence so far.

UL
the Rotax engine is a water-cooled head and a bit different to an air cooled TCM/LYC etc in that respect. It has a similar compression ratio or a bit higher and 26DBTDC, so it is taking advantage of the H2O and 98PULP
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Old 21st Jan 2014, 08:13
  #98 (permalink)  
 
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There are a wide range of different "Jabiru" engines including newer variants from those who actually make them. Some core improvements I think. First is to return to older solid lifter design, new cylinders and some head upgrades.

Isnt a key problem with Mogas the longevity and variable performance this brings, let alone other more detailed problems outlined by others

I have an 800hr 3300 with very few problems, Jabiru have always been excellent to deal with.
Always fly with an eye for a landing spot.....doesnt everyone flying singles?

They arent Rotax 912 or 914, few pretend they are, these Jabiru cost way less to own and operate, an entire brand new 120 hp engine is ~$19K.
Cheap and easy maintenance doesnt always equal well done and sure theres some conflicting service and operation data out there.

As far as DS problems go, maybe Im mixing incidents but heres an engine running on mixture of fuels, overheated (something gone very wrong), significant SB not carried out. At least a few issues piling up. What did you expect Jabiru to do? Seems they may have offered reco parts.

How recently have you gone back to Nissan or Toyota with a fatally busted engine and been received warmly. How about a LAME after a rebuild?

Jabiru do use std W100+ oil, significant work has been done to look at better options in the future, hopefully correcting some problems.
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Old 21st Jan 2014, 09:40
  #99 (permalink)  
 
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Good onya jet. Glad jab have treated you well, but like you said, you havnt had any issues with your engine yet ay? So applaes for apples..your selling oranges.
When did DS say he ran a mixture of fuels? He ran 98 octane. Very rarely the tanks got topped up with AVGAS. in the 300 hours in question, probably 30 or 40 litres TOTAL avgas.
What SB was not carried out on these two engines?
As far as im aware jabiru haven't recommended W100 oil for some time. I could be wrong but i recall them insisting we change to 15/50 some years ago.
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Old 21st Jan 2014, 10:39
  #100 (permalink)  
 
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Aeroshell 100 for run-in.
W100+ for continued use.

Don't confuse the W's and the +'a as there is also a W100 with no plus.
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