The Pacific: General Aviation & Questions The place for students, instructors and charter guys in Oz, NZ and the rest of Oceania.

Jabiru Bad experience

Old 20th Jan 2014, 05:16
  #41 (permalink)  
 
Join Date: Nov 2008
Location: nowra
Posts: 50
Likes: 0
Received 0 Likes on 0 Posts
Not sure XXX. Id be very reluctant to send anything to the factory that i wanted back
Thank you for the positive comments regarding putting the planes on line with another school. The owner just needs to advertise for a school that uses a crystal ball to know exactly when a normal operating engine will go super nova in 5 seconds time huh?
if your looking for a copout on not IAW with jab manuals then your barking up the wrong tree.
This maintainer was ANAl about that, and even helped jab FIX some of their discrepancies in their manuals which we discovered existed after following them during install and finding that they had been put in backwards. Very clear, simple F@#up by jabiru. Discovered after yet ANOTHER component failure.

The logbooks on all these aircraft have been inspected on several occasions during RAA audits and insurance claims.

Cheers
motzartmerv is offline  
Old 20th Jan 2014, 05:31
  #42 (permalink)  
Thread Starter
 
Join Date: Feb 2011
Location: Nowra
Age: 47
Posts: 21
Likes: 0
Received 0 Likes on 0 Posts
XXX your confusing two different aircraft here mate, The independent report is for the 3300 in my 230, the reason there was no log book at jabiru when it was independently inspected was because it wasn't requested, Jabiru did however request extracts from it! Yes of course the engine was maintained by the book and torque checks of the thru bolts conducted at the settings advised by the factory (if I recall somewhat lower than initial settings)


Only number 4 head from that engine reached a temp above 200c, shows how invested Jab are in the facts when plying their facts on failures.


The cracked heads and the valve seat failure are from the 160 all within 300 hours from Top end overhaul and no this engine was never at Bankstown since they O/H'd it.


Its not a falling out with Jabiru mate, I am posting my experiences as stated previously to inform people, yes they are entitled to make up their own mind either way and im not trying to sway it, just the raw facts!


I am so sick of people wading in accusing a Jabiru owner of incorrect maintenance or operation, give me a break please its getting old.
deadstick1 is offline  
Old 20th Jan 2014, 05:32
  #43 (permalink)  
 
Join Date: Sep 2009
Location: space
Posts: 389
Likes: 0
Received 1 Like on 1 Post
I have had 4 engine failure in my 6600hrs experience.

All four in Jabiru 2200 aircraft.

Two engines cut out short final when power reduced to idle for landing.

One cut out during a stall practice at 4000ft in training area accompanied by a wing drop at the stall. Exciting! Restarted ok.

Final one was loss of oil pressure in circuit on downwind. We landed immediately and the engine started vibrating wildly on touchdown.
Subsequent investigation found that on downwind the oil pump jammed up with pieces of valve tappet adjuster screws that had shattered, and engine went completely out of timing on landing.

You will never ever get me back in that piece of $hit wing cracking, engine failing, random flap retracting, small wheelled uncomfortable aircraft.

Z.
zanthrus is offline  
Old 20th Jan 2014, 05:37
  #44 (permalink)  
Thread Starter
 
Join Date: Feb 2011
Location: Nowra
Age: 47
Posts: 21
Likes: 0
Received 0 Likes on 0 Posts
Zanthrus, can I use that bottom line? very funny, thinking of ideas for side stripes on the 160...
deadstick1 is offline  
Old 20th Jan 2014, 05:50
  #45 (permalink)  
Thread Starter
 
Join Date: Feb 2011
Location: Nowra
Age: 47
Posts: 21
Likes: 0
Received 0 Likes on 0 Posts
XXX,
heres two of the reasons Jabiru gave me for the J160 heads failing, the other was to accuse me of running an additive. I quote Sue woods the business manager:-


"The word from the engine section regarding the heads is that there is evidence of overheating of the exhaust port areas probably from leaking exhaust pipes. This overheating has resulted in the valve seats dislodging and valve stem damage. They suggest the installation of EGT monitoring as an early warning for leaking exhaust pipes. Also carburettor jetting can be checked against the EGT measurements on the Mogas, Avgas and mixture of Avgas and Mogas. The cracks in the heads may have been caused by the overheating though they don’t appear to have contributed to the engine failure. For any more information speak to Mark in the engine section."


XXX, point of note a full brief of equipment fitted and conditions at the time was sent, they missed the fact that it had the desired sensors, also if you read the report into my other engine, the 3300 you will note that Jabiru state that the seats will start to fall out at 250c. also they found that one head had an exhaust leak at the flange, gripping at straws if you think that effected all heads... So I politely pointed out the inconsistency in their conclusion and got this:-


"Hi Chad

The engine section has examined the heads and the piston and cannot see any manufacturing defect that has caused this damage therefore we will help as far as providing the 2nd hand heads as quoted. If you want to send us the EMS data file we would be interested to see the EGT measurements against what fuel was in use. "


I have considered driving the 7 hours to get the EMS file for them, but I can guarantee it will show that they have been kept within limits! further all Jabiru would say if I tried to use that as evidence is that its a non calibrated instrument.


Sue has informed me that they will not be returning my heads, only after I requested them back for a third party to inspect and report on, she quoted her requirement to hold them in quarantine for one year so CASA can inspect. I provided her with this from the section head of defect investigation at CASA:


Hi Chad,

This email formally notifies you that under Civil Aviation Regulation 52B(3) that your Jabiru cylinder heads are not required to be kept in a state which allows CASA to investigate the defect.


Still refuses to return my property.







deadstick1 is offline  
Old 20th Jan 2014, 05:51
  #46 (permalink)  
 
Join Date: Nov 2008
Location: nowra
Posts: 50
Likes: 0
Received 0 Likes on 0 Posts
Why would they need a log book to explain how and why an engine failed? Its simple. They pull it apart, find the broken bit. The blaming of the operator (need for log book) would come later yea? Thats the usual routine isnt it?
"oh, youve overheated it"
" umm, no I havnt, I have 4 channel EGT/CHT for entire life of (rebuilt) engine which clearly shows always in specs."
"Oh, well, in that case, you used the wrong fuel additives"
"Ummm, no, i dont use fuel additives"
Oh...fair enough, well, then im afraid youve overheated it"..
"Ummm..havnt we been over this?"..
"oh yea, sorry, i got confused who i was talking to. You must understand we deal with a lot of these failures every week, I got confused"
"ok, so can you please tell me why my factory engine died at 300 hours?"
" Yes, we probably can..But..Not right now..We want to quarantine the parts so casa can see them...one day..maybe."

"Ok, just let me know please..Now, can you put me through to the sales dept..i need to buy some new parts to fit to my factory engine that doesnt work anymore"
"yes certainly sir"


While you may think this is a joke, i assure you its not. every part of that conversation I have witnessed first hand.
motzartmerv is offline  
Old 20th Jan 2014, 06:34
  #47 (permalink)  
 
Join Date: Feb 2006
Location: Mel-burn
Posts: 4,875
Likes: 0
Received 0 Likes on 0 Posts
All four in Jabiru 2200 aircraft.

Two engines cut out short final when power reduced to idle for landing.

One cut out during a stall practice at 4000ft in training area accompanied by a wing drop at the stall. Exciting! Restarted ok.
I chuckled when I read this, so you have had one genuine engine failure that can be attributed to the condition of the engine.

Adjustment of the idle stop is hardly a fault of the engine or engine manufacturer !
VH-XXX is offline  
Old 20th Jan 2014, 06:50
  #48 (permalink)  
 
Join Date: Nov 2008
Location: nowra
Posts: 50
Likes: 0
Received 0 Likes on 0 Posts
Yea, hafta agree. It seems your engines were idling to slow.
I once did the testing for a Jab powered homebuilt. For some reason, the engine would idle normally on the ground, but in flight would idle down and stop. Was strange and counter intuitive. I cant recall the reason. Sorry, getting old..
motzartmerv is offline  
Old 20th Jan 2014, 07:06
  #49 (permalink)  
 
Join Date: Jul 2007
Location: in the classroom of life
Age: 55
Posts: 6,864
Likes: 0
Received 1 Like on 1 Post
I have considered driving the 7 hours to get the EMS file for them, but I can guarantee it will show that they have been kept within limits! further all Jabiru would say if I tried to use that as evidence is that its a non calibrated instrument.
Well I would happily look at it for you, but can I say that there is no such thing as an EGT within limits, except when talking about a TIT, but that is not relevant here.

Have you been using Avgas? Mogas? and which sort and where from?

And just in case you are wondering ....which do you think has the highest EGT and which is the better off the two?

And just before you think I have any involvement with Jabiru, I do not. But I might be able to offer rational understanding of engines the data and they fuel used. Gidday Wally!
Jabawocky is offline  
Old 20th Jan 2014, 07:23
  #50 (permalink)  
Thread Starter
 
Join Date: Feb 2011
Location: Nowra
Age: 47
Posts: 21
Likes: 0
Received 0 Likes on 0 Posts
Jabbawocky,
mogas, higher EGT than avgas.
deadstick1 is offline  
Old 20th Jan 2014, 07:24
  #51 (permalink)  
 
Join Date: Aug 2000
Location: (Not always) In front of my computer
Posts: 371
Received 0 Likes on 0 Posts
M,

For some reason, the engine would idle normally on the ground, but in flight would idle down and stop. Was strange and counter intuitive.
My best 'guess' would be induced prop drag due airspeed. I used to operate a C206 that would slow the idle when turning right due (I'm told) to gyroscopic propeller influences. Never occurred when turning left.

An aerodynamicist or engineer may have a more qualified answer.
Two_dogs is offline  
Old 20th Jan 2014, 09:10
  #52 (permalink)  
 
Join Date: Jul 2005
Location: Queensland
Posts: 686
Likes: 0
Received 0 Likes on 0 Posts
Deadstick 1 you have one more guess. I'll let Jabba explain why. Cheers RA

Hint:- Compare what happens after the spark event using the two different fuels. Especially look at peak pressure and where it occurs and what happens to CHTs The timing and RPM should be the same for both fuels when you do the comparison.

Last edited by rutan around; 20th Jan 2014 at 09:42.
rutan around is offline  
Old 20th Jan 2014, 09:21
  #53 (permalink)  
 
Join Date: Jul 2011
Location: nosar
Posts: 1,287
Received 23 Likes on 12 Posts
Adjustment of the idle stop is hardly a fault of the engine or engine manufacturer !
Yea, hafta agree. It seems your engines were idling to slow.
Nothing like judgement by your peers

The two J160's I have time in both have a peculiarity. If the idle is set correctly and a ham fisted pilot heaves the throttle shut the engine stops. If the idle speed is set high so the engine can't stop with a hard yank on the throttle then excessive braking is required or you need to instruct to pull the throttle very hard and keep the pressure on. There is a flex in the system somewhere that I have NEVER encountered in any GA aircraft. Gifted engineers have looked at these two aircraft, the best they come up with (failing modification) is a compromise, high idle or an engine that can be stopped by hauling hard on the throttle.

I know the problem Zanthrus, I have seen it, having a prop stop on final or on the runway is not really my cup of tea.

That said, both aircraft have had no engine problems, both have 2200 hours and both have had engines replaced (in lieu of a top overhaul) every 1000 hours.
Aussie Bob is offline  
Old 20th Jan 2014, 10:23
  #54 (permalink)  
 
Join Date: Nov 2008
Location: nowra
Posts: 50
Likes: 0
Received 0 Likes on 0 Posts
hey Bob. No judgment mate. Just a possible explanation to his woes..Which you subsequently provided further evidence for. Judgment? or discussion..?

Ive not come across that problem in jabs. You must have some strong handed pilots there, pulling on that throttle.
motzartmerv is offline  
Old 20th Jan 2014, 10:30
  #55 (permalink)  
 
Join Date: Jul 2007
Location: in the classroom of life
Age: 55
Posts: 6,864
Likes: 0
Received 1 Like on 1 Post
Rutan around..... Good work there. Clearly not rutanaround at the back of the class were you. Unlike a couple of other ppruners

deadstick
The shorter latency of mogas Vs Avgas means that the peak pressure is higher and so is the CHT. Neither of these things is optimal.

The spark timing is fixed at 25DBTDC and being a direct coil on the flywheel system this will mean the spark (in theory) will fire sooner than that of a conventional magneto, but only a little. It could be said that the plugs location partially offsets this, but I do not know that for sure. (Flame front propagation).

High CHT, poor fuel quality, and with MOGAS there is not guarantee, there could be increased peak pressure and thus CHT. Add to this induction leaks and or the ordinary fuel distribution and how you know what was happening.

My suggestion is that with Mogas compared to Avgas all things being equal, you had higher CHT and lower EGT.

There is a large difference in Octane rating. So specifically which Mogas were they using and from where?

So getting back to the failure with a rapidly rising CHT and the two instructors on board, have you any photo's of the failed cylinder?
Jabawocky is offline  
Old 20th Jan 2014, 10:33
  #56 (permalink)  
 
Join Date: Jul 2010
Location: rangaville
Posts: 2,280
Likes: 0
Received 0 Likes on 0 Posts
Hey hold on, I was up the front

There might have been a bit of rooting around but I got the most important question right
Jack Ranga is offline  
Old 20th Jan 2014, 10:39
  #57 (permalink)  
 
Join Date: Nov 2008
Location: nowra
Posts: 50
Likes: 0
Received 0 Likes on 0 Posts
Do Jabiru certify mogas in their engines? If so are there any modifications needed (IAW with the maintenance manuals) to account for this issue?
Another question. How do other aircraft engines that allow both types of fuel handle the issue? Im assuming the engine manufacturers have similar or dare I say it, better knowledge about these problems?
motzartmerv is offline  
Old 20th Jan 2014, 10:49
  #58 (permalink)  
 
Join Date: Feb 2006
Location: Melbourne
Posts: 1,693
Received 0 Likes on 0 Posts
Another question. How do other aircraft engines that allow both types of fuel handle the issue? Im assuming the engine manufacturers have similar or dare I say it, better knowledge about these problems?
There is a bucketload of material on this. Try this to start. You'll find more with the EAA, possibly AOPA and I think the Cafe Foundation.

Petersen Aviation | Auto Fuel STC

In short (aside from octane issues) Mogas compatibility has to do with fuel pump configuration and fuel line fitting metal composition. The engine itself doesn't care much, its all about getting it to the engine.
Old Akro is offline  
Old 20th Jan 2014, 10:50
  #59 (permalink)  
 
Join Date: Feb 2006
Location: Mel-burn
Posts: 4,875
Likes: 0
Received 0 Likes on 0 Posts
It is impossible to pull the throttle rotating mechanism past the stop located on the side of the carburetor, basic physics that one!

If the engine stops when the throttle is pulled out of the dash regardless of the strength of the pilot(s), then the idle stop is incorrectly set. Pretty simple really.

What will be wrong in the instances of stoppages mentioned above, is that the location of the cable assembly is incorrect both where it passes through the firewall and also through the holder attached to the carby. In all honesty if your mechanic can't get this right, they should stick to lawn mowers and I'm not referring to ultralights either. Failing that the problem will go away after replacing the throttle cable. I would be more than happy to demonstrate the correct fitting of the cable whenever I next pass through wherever this problem exists.


You will never ever get me back in that piece of $hit wing cracking, engine failing, random flap retracting, small wheelled uncomfortable aircraft.
Would love to hear more on the wing cracking and random flap retraction. Both of those if reported would probably warrant an SB. As for random flap retraction, they are either manual flaps on an old LSA55 or electric in the J160 onwards and short of some shoddy maintenance I can't imagine why the flaps would randomly retract. No wonder these aircraft are getting a bad name when mechanics can't seem to look after them properly.
VH-XXX is offline  
Old 20th Jan 2014, 10:55
  #60 (permalink)  
 
Join Date: Nov 2008
Location: nowra
Posts: 50
Likes: 0
Received 0 Likes on 0 Posts
Yes yes. I get that. But, im saying that clearly there are engines that are designed to run on both types of fuel. My question is, what, if any measures do operators of these engines have to take when running the different fuels to account for these problems.. Apart from the rotax schedule of extra oil changes. Whats the difference. if its enough of a difference for some of you to blame the fuel for overheating the engine to FAILURE, then surely it would be enough of a difference to warrant standardised handling of the engines with different fuels.. of which there is non that im aware. Please tell me if im wrong.
motzartmerv is offline  

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.