Another Jab bites the dust.

[Hongie]

i must add too, well done to the instructor/student.

 

I too am a low hour newly minted 'pilot' and seriously, as much as i love flying and aircraft, if someone offered me a ride in a jab powered aircraft, i think i would give it a miss! I know a failure can happen to any powerplant, not just jabs. I'm a diesel fitter/motor mechanic, and i've seen some catastropic engine failures in industrial motors like cat 3126's that are supposedly bulletproof, but jabs now have such a bad record, i dont think its worth tempting fate honestly. Give me Rotax or lycoming. Hell, give me a greatplains vw, or a subie ea81! I had a subaru brumby with an unopened ea81 with 400k k's on it!

 

My 2c worth

 

 

[Guest ozzie]

Why do people use Jabs for flying. Cost effective. Initial outlay compared to import prices. Low airframe maintanence composite vs tin. Well on paper it is. How it works out in real life is another thing.

 

I had a fly of a VH Brumby a couple of weeks ago. Jab 6 cyl. Had some experience before with one fitted to a Storch. Lots of problems with that engine but most related to the aircraft design it was fitted to. Very slow climb speeds never gave it a chance to stay cool and barely enough airflow in cruise. Both 4&6 cyl engines need to carry a couple more litres of oil and better oil cooler. But a couple of incidences that just came down to the engine componets themselves.

 

Back to the Brumby. Nice aircraft. I found it a little light on the stick. Easy to fly with just your finger tip on top of the stick.

 

Engine. A lot of changes to address the common issues plus well built cooling baffels and seperate directed air to the coils and such. It ran very well. Hummed along. But the induction system could do with a rework to get everything level on the CHT and EGT bars. But i never looked to far away from the river flats, you guys have me spooked with those stories.

 

 

[Doug Evans]

There a lot of them for sale I stick with my 582 s !

 

 

[rankamateur]

So many of the ones for sale have total time neatly twice the engine time, so the owner is rightly getting nervous, can't blame them, who wouldn't be.

 

 

[Guest Maj Millard]

Well I think you all know what I think of the damn things !...we have an Australian hand-grenade now...obviously the factory isn't listening, or simply doesn't care...either way it's not acceptable in a training fleet, innocent students are just going to get hurt unecessarily, and then we'll see really good instructors like Motz either get sued to oblivion, or leave the sport in disgust...over it Rod, fix the damn things or take them off the market !.......................Maj...

 

 

[frank marriott]

I am not supporting any engine but I get a gut full of continual Jab knockers who have no direct involvement. Mots excepted in this actual thread.

 

The rotax engine failure at Stark filed, [pilot still in hosspital 2 weeks later] and the fatal at Cabulture another Rotax [OK sorry they are other aeroplane accidents not ROTAX powered engine failures???? because Rotax don't fail]

 

Can we have a sensible anaylysis of each engine failure or do we just do the three stooges thing and only talk about Jab problems.

 

I am interrested in every engine failure and the cause but some on this site are overboard and if they have money invested in a particular engine then they should declare their commerical interest and if not then maybe they should seek professional help

 

I am not in love with any piece of metal but if we cannot look at each problem and analyse what is happening like normal adults : then I will leave the future comments to the poorly informed ROTAX society

 

I don't think that is the case with most on this site but I will watch and if no commen sence can be achieved I will take my own course of action.

 

FrankM

 

 

[Guest Maj Millard]

Frank, You view is suitably taken. We have been discussing the through-bolt problem now for probabily three years or at least two years. Several of our forum members (myself included), have offered really good suitable alternatives to the problem. One member in WA has gone out of his way to source a good alternate through bolt. My question, and that of many other concerned people, is what has the factory done for you ?................................Maj...

 

The Rotax engine failure at Starke that you mention,(new 503 DIDC) which I looked at today in fact, in my opinion may have been caused by the use of that silly blue plastic polyethelene fuel line, as the line between the engine case and the fuel pulse-pump. The engine pulse is a push-suck thing, and I believe this blue line may have collapsed at full power, and rendered the fuel-pump inoperable. There have been cases of this happening before. Rotax recommends high-quality rubber hose be used in this area. I can't believe the blue stuff has reappeared on the scene again. I cannot prove this is the case, but if so, as I believe , then it's certainly not a Rotax failure.

 

I have no direct info on the Cabulture fatal, but I believe the professional airline pilot failed to make the airport after an engine failure in the circut. Ah, surely this could have occurred with any engine ??

 

 

[frank marriott]

Ross

 

Exactly what I am saying - direct factual comments and not anty Jab dibble is of interest to everyone.

 

I have posted two IO540 head failures here before but as things happen with any engine it is all interresting when viewed factually

 

Facts are interresting to everyone - personal bias I would suggest is of no help to anyone and only of interrest to the individual posting

 

FrankM

 

 

[damkia]

Is there any statistical data from accidents and incidents that could be made available into a table giving engine type, hours total, hours since last O/H or 100 hr, type of failure (what broke), mode of failure (how it broke), and severity of failure (rough running <-> total loss of power), but only concentrating specifically on the engine rather than the airframe/pilot error/other issues usually included in incident and accident reports? ie, pick the bones out of every engine failure report to establish a clear data set to base any recommendations on. (back to manufacturer/CASA/RAA?).

 

As an interested observer at the moment, there doesn't seem to be any collected data to support any arguments other than anecdotal or empirical experiences presented here and in other forums. What is needed is hard numerical evidence.

 

 

[deadstick]

Hi Frank,

 

I am a Jabiru owner (J230) as well as a Licensed engineer, I am continually confronted with engine failures of the Jabiru brand and can say that the other brands pail into insignificance when compared on reliability(local snapshot). I maintain multiple types and am one of the ULPOWER service agents in NSW. I was called to diagnose the cause of the failure for this particular power plant and whilst the analysis is incomplete I can confirm that it has suffered a through bolt failure at a grand total of 270 hours post Jabiru factory overhaul! this particular unit in its current state has a total of 1370 hours and has required 3 top end overhauls in this period, the engine is of the latest incarnation (shims under the barrels to assist with detonation issues and oil fed pushrod tubes) but came out of the factory just prior to the upgraded through bolts. Whilst I have no statistics to appease your desire for thorough objective analysis. From my own observations the Jabiru range of engines suffer from poor quality control and inadequate conditioning for the Australian environment in which they are marketed for.

 

Purely my humble observation and not intended to belittle or offend, but I can tell you the amount of time I have spent on my own 3300 to get it right (and a top end overhaul at 230 hrs) as well as the constant tinkering and failure rectification, causes me to fly from Paddock to paddock just in case! I get to relax behind the Rotax 912 in a friends A/C and enjoy flying! LOL

 

 

[frank marriott]

deadstick

 

I am happy to hear what you say from personal and informed opinion. More then happy - INTERRESTED.

 

Direct knowledge [especially informed knowledge] is great and one of the reasons I regularly visit site.

 

What I get sick of uninformed crap from anyone with a particular bias. I own a Jab 3000 engine but I am not promoting it, and interrested with all problems that arrise. Just I am sick of reading anty Jab rubbish fr0m the uninformed that contribute nothing to a suggested problem.

 

FrankM

 

 

[deadstick]

Frank,

 

I respect and hear what you are saying.

 

 

[turboplanner]

Tell you what I'll do Frank, I've just pulled out all my magazines and I'll database for you all the through bolt failures listed.

 

 

[Powerin]

Well done Cory! I just hope I remember my training and procedures as well as you did if it ever comes to the crunch.

 

I'm curious, and perhaps others might like to comment as I'm not a mechanic: thinking about cause and effect I'm wondering if the root cause of Jab's problems could be the induction system? I've read many, many pages of people struggling to even out EGTs in their Jab engines. If detonation is indeed the cause of through bolts breaking, would cylinders consistently running too lean contribute to this?

 

 

[Guest Maj Millard]

Frank, I certainly cannot be accussed of personal bias in this case. Motzartmerv reported that his engine failure was the result of a throughbolt failure...pure and simple...and yet another one, in a training aircraft !. I was simply responding to that report. I have replaced at least five 912s from trainers, that have done their hard hours to TX (1200-1500 hrs), without any major failure in between. They do the hours- period. These are the engines that need to be in our trainer aircraft, not something that could, and does fail at low hours unexpectantly. You say you only want the facts, well I'm sorry my friend, those unfortunatly are the facts.....And further, please don't refer to me as uninformed on the subject, go back through the threads, you'll find I was the one who originally suggested the use of rolled threads over the factory supplied cut threads, ..................................................Maj...

 

 

[Thirsty]

I'd be interested to hear what mod status this engine was at. We've recently changed the thru bolts on a 600 hour engine to the new bolts and nuts and it recently broke a flange on number 4 cylinder. The thru bolt was fine.

 

I think detonation is the main problem with these engines as well.

 

 

[Guest Maj Millard]

I'm currently reading a three book series on the history of Rolls-Royce, and in particular their trials and tribulations with the Merlins during the Spitfire period of WW2. Detonation was no stranger to them either, but the solutions are well known.

 

Jabaru are producing aircraft engines that are used in training aircraft. They need to sort out their problems just like RR had to almost 70 years ago !.........................................................Maj...

 

 

[RKW]

Well done Cory! I just hope I remember my training and procedures as well as you did if it ever comes to the crunch.I'm curious, and perhaps others might like to comment as I'm not a mechanic. Thinking about cause and effect I'm wondering if the root cause of Jab's problems could be the induction system? I've read many, many pages of people struggling to even out EGTs in their Jab engines. If detonation is indeed the cause of through bolts breaking, would cylinders consistently running too lean contribute to this?

Detonation is almost certainly the cause and to remedy this problem, Jabiru have reduced the compression ratio and increased the size of the main jet. Now they have increased the threaded diameter of the thru-bolt which should have a better chance of keeping the two halves together. My J160 has the new thru-bolts so I am keenly interested to see how it holds up! It is used for training, so it should get the hours up rather quickly. Bob

 

 

[deadstick]

Powerin,

 

what your saying has its merits and I can tell you my 3300 has been a PITA to get the egt's within a near envelope, I recently changed the manifold to the newer design (post change EGT/CHT pic attached), I run it on the richer side in attempt to make O/H times and can say the Compressions have remained solid since I rebuilt the top end (machined close to max piston and cyl clearance) but suffered number 4 exhaust valve burn out 250 hours later. does not give me a warm and fuzzy feeling at all!

 

 

 

[Camel]

Motz, what fuel do you use in this aircraft.

 

 

[M61A1]

deadstickI am happy to hear what you say from personal and informed opinion. More then happy - INTERRESTED.

Direct knowledge [especially informed knowledge] is great and one of the reasons I regularly visit site.

 

What I get sick of uninformed crap from anyone with a particular bias. I own a Jab 3000 engine but I am not promoting it, and interrested with all problems that arrise. Just I am sick of reading anty Jab rubbish fr0m the uninformed that contribute nothing to a suggested problem.

 

FrankM

I would be more concerned if a forum such as this ( which is here for the purpose of discussing these types of event), limited the discussion to only those who have personally experienced the event themselves.

I have not seen any post which suggests that rotax engines do not fail, just (and justified) concerns over why there are apparent reliability issues with Jabiru in particular (being pretty much the topic of the thread).

 

Even if one does not own or fly a Jabiru engined aircraft, you only need to look at the 'Pilot Notes' section of any RAAus magazine to notice almost without fail, there is one or more incidents involving a Jabiru engine making bad noises and losing power or stopping. While I agree that some thing could have been better put, it is still an open discussion, and all are entitled to an opinion.

 

 

[Vev]

Hi Motz,

 

Where is the engine in terms of the through bolt and dowels ... what is its current status?

 

Helpful to know the facts on the through bolts and nuts to help getting a better understanding of the issue?

 

Glad all worked out for everyone.

 

Cheers

 

Vev

 

 

[deadstick]

Hey Vev, from prev post

 

Hi Frank,. I was called to diagnose the cause of the failure for this particular power plant and whilst the analysis is incomplete I can confirm that it has suffered a through bolt failure at a grand total of 270 hours post Jabiru factory overhaul! this particular unit in its current state has a total of 1370 hours and has required 3 top end overhauls in this period, the engine is of the latest incarnation (shims under the barrels to assist with detonation issues and oil fed pushrod tubes) but came out of the factory just prior to the upgraded through bolts. .

[Vev]

Thanks Deadstick,

 

Wasn't the new through bolt AD deadline 14/4/12 and all engines required the upgrade by then?

 

http://www.jabiru.net.au/Service%20Bulletins/Engine%20files/JSB031-1_JSD031-1_Engine_Through_Bolts.pdf

 

Cheers

 

Vev

 

 

[deadstick]

O/H may 2011, IIRC