Another through Bolt gone

[Guest Maj Millard]

Any LAMEs or l2-l4s want to comment?

 

I am two of the above and have been one for around 45 years professionally. (guess which two ?..)

 

I gave up 'Jab bashing' as the Jab owners call it, about two years ago. (Whoops..looks like I just took it up again!.)..It's a wasted effort, most of them are just not listening to good advice anyway!....

 

The worlds' engine manufacturers have been producing quite successfull, aircraft air-cooled engines now for over a 100 years !..The facts and figures are all there in the aviation-science text and reference books, on how to do it, utilizing pressure drops etc. Why can't Jabaru do it ?...because they aren't listening.

 

It's about proper airflow, adequet oil-cooling, and using the correct metals to build the engine from in the first place!...

 

For an engine manufacturer to suggest you need 80 kts to cool an engine is almost criminal. An aircraft engine needs to be able to cool itself on those hot days, when your sitting there idling, three aircraft from the threshold, or as a Jab certified and recommended trainer, when doing circuts which is by the way how most learn to fly, remember ?..

 

Blame the hydrylic-lifters ??...what a load of croc...most modern cars (I bet your driving one !) have used them quite successfully for years now. The only time you'll ever have a drama, is when you neglect your oil changes, and the oil gets really sediment-laden. Even then most of the time, they'll still work just fine. Rotax doesn't seem to have too much trouble with theirs.

 

I don't really blame the owners, except that I really wish they had complained more, earlier about the problems, instead of just going along with all the factorys' BS. Things may have been fixed by now.

 

We can only hope and wish that when CASA is finished buggerizing around with our 'not broken' aircraft registration system, that they decide to do some real safety related good, and look at the Jab engine manufacturer, an engine which they themselves certified !!.................................no apoligies to anyone ................Maj...

 

 

[Sapphire]

Mechanical valve lifters just have an airspace of a few thou which has a simple screw adjustment to adjust for even the most exaggerated wear in the valve train. As an example of the nightmare of hydraulic valve lifters, I'll use the Continental 0-200. To set it up you have to deflate the lifters first. By Continentals method you have to remove and dissasemble each valve lifter to drain out the oil and reasasemble. That means taking the cyl head off, removing the retaining circlip holding the lifter and lifting it out, disaasemble, clean out oil, install, and replace cyl head. Now you have done this to one cyl head [two lifters], do this again times the number of heads there are. Remember lifters don't come apart alway easily-some are bastards to get apart. Ok you have the lifters deflated and you measure the tappet clearance which must be between 30 thou and I think 110 thou. If not, start looking around for spare pushrods which vary a bit in length. No luck, start replacing parts in the valve train including the valve it self, if the stem is not the right length. That means taking the cyl head off again. All this can be adjusted out with the turn of a screw in mechanical valve lifters.

 

Mechanics fee to adjust 4 cyl with mechanical valve lifters=about two hours labour[if competent] half that time to position a/c, remove and reassemble cowling.

 

Mechanics fee to set up hydraulic valve lifters-get an estimate, double it, and prepare to to hand over LARGE wads of dough. If he is not honest he will try to con you into a major overhaul, "just to be sure"

 

 

[Phil Perry]

Would you buy another car from the same manufacturer if you'd had 3 of their engines bite the dust inside of 12 months during routine driving?

I'm not really in a position to make qualified comment regarding Motz's engine failures, . . . . . but I think your well articulated comment pretty well puts the situation into perspective Sain.

 

Here comes the "However"

 

I'd have to point out that the last bit ( as quote ) wasn't really a realistic comparison. a Not many aircraft are worked harder than those used for training pilots. Apart from the exmples you may see on "Bush Pilots" "Ice Pilots" and other TV shows.

 

To compare a school training aircraft with one which is used under the heading "ROUTINE" is a bit off the wall. ( Yes. . .I KNOW schools have routines too, but I'm sure you can see what I'm getting at)

 

The sometimes drastic operations in which training engines in training aircraft are used, will often result in shock cooling, ( PFL, then sudden application of full throttle. . . ) as a previous poster mentioned, and of course, solo students not warming the engines correctly on a frozen English morning . . . . and then revving the guts out of it. Something a loving / sensible private owner would never (! ) do. . . .

 

Can't compare the family Holden Kingswood with a Monaro turbonutter car which trains blokes to stay on the track at Bathurst. . . .

 

The thing you guys have got, which we have not. . . . is a much higher average ambient temperature most of the year round, I'm sure this means that a LOT more care needs to be taken in engine operation.

 

As for Motz's problem, which sounds awful, I have no suggestions, I've never dealt with them, ( another However) perhaps since they are a manufacturer based in AUSTRALIA one could assume that NAtional ambient temperatures would have figured large in the original design calculations for that engine ??. Or is the underlying suggestion that this thread concerns a lot more than just operating temps . . . . . .?

 

Phil

 

 

[motzartmerv]

but jabiru? this is acceptable..

Unfortunately not only acceptable....Required by AD.

 

This latest one comes about 150 hours since the "mandatory' change of the nuts. Id bet my hat the stud would NOT HAVE SNAPPED if it was left alone.

 

 

[turboplanner]

We've had a number of very interesting discussions on it Phil, but so far none of us have been able to pinpoint the deign issue around the through bolts.

 

 

[Phil Perry]

We've had a number of very interesting discussions on it Phil, but so far none of us have been able to pinpoint the deign issue around the through bolts.

Geeeez,. . . . . I wonder if the 8 Cyl Jab engine which powers the very popular Mk26 Spitfire kit has the same stud design. . . . . .? Have not noted any rumblings on the UK Forums thus far though. . . . . . I'd be really ticked off if I had to force - land my BAttle of Britain pride and joy into a deep ploughed field, ( But that's only because I always panic when the engine stops . . . . . )

 

( * * *Editor's note,. . . . NO I DON'T own one, didn't intend that inference. )

 

Some poor millionaire just had a probbie when his Mk 9 REAL SPITFIRE undercarriage collapsed on the runway at East Midlands Intl Airport last week though, I'll bet he is a bit on the peeved side. . . . .

 

 

[motzartmerv]

Do they still manufacture the 8?

 

 

[Phil Perry]

So an Australian company produces an aircraft for sale in Australia which must not be operated in temperatures above 38C ??.

Yes Clive, that's right BUT. . . . when I was flying in OZ in the early seventies. . . , they reckoned if you could get about five thousand feet under yer wings really quick,. . . . . the temperature up there would be magically reduced by roughly ten degrees C !!!!!!!!!!!!!!!! Summat to do with ( especially when it ain't raining. . . ) the D.A.L.R. or, Dry Australian Lapse Rate . . . . . or,. . .hang on, am I confusing this with the speed that Aussie pubs are closing due to the Smoking Ban, ,. . . . . . dunno, I could have a crack in my thru bolt. . . . ?

 

Did I forget to wish you JOYEUX NOEL Monseiur ?? can't remember. Anyway, consider yourself Greeted.

 

Phil

 

 

[rankamateur]

The thing you guys have got, which we have not. . . . is a much higher average ambient temperature most of the year round, I'm sure this means that a LOT more care needs to be taken in engine operation.

Phil

Taking you theory Phil, should we expect even more problems with an engine made in Austria because of the greater difference between the ambient temperature in Australia compared to the factory?

 

Doesn't seem to be the case does it?

 

 

[Guest Maj Millard]

 

 

I really think you mean remove the valve-covers there Sapphire don't you!... In fact I'd really like to see you remove the head off the barrel of one of those engines !.... Bleeding down the lifters as required on Continental or Lycoming engines is not that big a deal once you know how to do it, and it can be done much quicker than described by you, by the average experienced LAME.

 

 

 

As for finding different length pushrods, or changing valves with different length stems...well thats a jab thing, and is certainly not a recommended proceedure on normal servicing of Continental or Lycoming engines. It may be something that is done during an engine overhaul. It shows just how far out on their limb Jab is to recommend this rubbish just to keep their engines running..............................................Maj...

[vk3awa]

Unfortunately not only acceptable....Required by AD.This latest one comes about 150 hours since the "mandatory' change of the nuts. Id bet my hat the stud would NOT HAVE SNAPPED if it was left alone.

Motz,

Unfortunately my "educated guess" is the bolt possibly would have.

 

The root cause of the bolt failures is probably not the bolts or nuts.

 

The 12 point nuts were implemented to stop through bolt failure....do they.....in your experience (and others) Unfortunately not.

 

I'm a cynic so I will go out on a limb and say the 12 point nuts may have been implemented to appease authorities.

 

 

[Phil Perry]

Taking you theory Phil, should we expect even more problems with an engine made in Austria because of the greater difference between the ambient temperature in Australia compared to the factory?Doesn't seem to be the case does it?

Read it again. . . . and it wasn't a theory by the way, just a com ment. . . . I said that "One could assume" . . . . . and from what I gather, the thread is mainly aimed at other design issues, and not just the operating temperatures you're going to get in a particular country. The last time I flew into Innsbruck, and out again the next afternoon, it was a balmy six degrees celcius, so overheating of the engines was not going to be figuring highly on the "Possible problems" I'm not suggesting that Ts and Psshould be left to their own devices, or not taken any less seriously in ANY stage of flight and if you buy an engine made in Austria, or anywhere else, it will have the engine temperature operating ranges tabulated in the POH. I have not seen one yet which doesn't. You then operate this in line with what the instruments tell you, whatever the OAT.

 

As you may well be aware, Rotax / Bombardier originally made their fortune supplying engines for snowmobiles or "Skiddoos" as the septics like to call them, which were designed to operate at a sensible and therefore useful and reliable engine temperature in sub zero environments, and as the timeline advanced, and they started making four stroke engines for us kitbuilders / Lsa, Ultralight and Microlight operators, they have refined their products to reflect the environments in which they are likely to be used. This is possibly why they are the largest supplier of this type of engine at the moment, and probably why the US Govt. buys whole production runs for their UAVs ( pretty hot in Afghanistan too I hear )

 

My comments were generated BECAUSE I READ all of the other posts in this interesting thread BEFORE commenting. You may agree if you also read them all, that there seemed to be some argument with regard to what was the correct OR max temperature allowable / recommended for Jab engines. I return again to my comment about designers, if I was designing something to operate in a country like Australia, and was an Australian, and BASED there,. . . . I'd certainly want to know if my product was going to be viable in those KNOWN climatic conditions, just like I would find it a bit daft to design a washing line hoist made of marzipan and try to sell it to India.

 

Kind regards,

 

NosensibletheoriesPhil

 

 

[Gentreau]

Taking you theory Phil, should we expect even more problems with an engine made in Austria because of the greater difference between the ambient temperature in Australia compared to the factory?

Actually the temperature in Austria varies enormously over the year (I lived there for 3 years). It can be -20C in the depths of winter and +45C in the height of summer. Maybe the Austrians just make their stuff tougher because of the extreme temperature swing ?

 

 

[Phil Perry]

Could be Clive. . . .COULD BE. . . . bloody teutonic efficiency, makes yer sick dunnit ? It's probably why the "S" series Merc is the best car in the world. . . . . . (Oops, sorry thats made byt the Jerries innit . . .)

 

It must be, cos Jeremy Clarkson says so. . . . . shame he lambasts us microlighters so much. . . . . .

 

 

[ausadvance]

I have been reading over this forum, and the mechanical and Jab issues aside, I am disgraced by the hostility and plain b*tching i have been reading. first of all guys calm down! I am not a fan of the jab aircraft myself, but that is just my opinion. Doesn't mean I need to come on a forum and whinge about it like a teenage girl. when it comes to mechanical and safety issues certainly have constructive conversations about things, but what I have been reading this morning clearly demonstrates why I refuse to call myself a pilot and just tell people I fly aeroplanes. we are all mature adults on here, we have to be to fly. lets act like it.

 

its like they say, "pilots, looking down on people since 1903!"

 

 

[Guest Maj Millard]

It doesn't really matter what the ambient temps are. That is a known factor that all engine designers need to consider. The engine (any engine) needs to be designed to handle a full expected range.

 

The Jab is an aircraft activly promoted and used widely, as an ab intio trainer.

 

As an example, I work with a company than operates Pratt& Whitney 985 powered DHC-2 Beavers on Amphib floats. They are air/oil cooled, and fly daily in all temps, often heavily loaded. (av right now about 32 deg C on a daily basis) They only run a smallish 8 inch circular oil cooler, and a hell of a lot more cubes and horsepower than any Jab !...(985 Cin..450 HP) We have no major cooling issues, and certainly don't need to maintain 80 kts to cool things. The aircraft generally don't go much above 1500 ft on their island-hopping reef runs.

 

The difference when compared to a Jab?.......much better design of the whole engine in the first place...........................Maj...

 

 

[Teckair]

A bloke I know from WA told me he knows someone in WA that is fitting a 115 HP Lycoming to his Jabiru J230.

 

 

[turboplanner]

I have been reading over this forum, and the mechanical and Jab issues aside, I am disgraced by the hostility and plain b*tching i have been reading. first of all guys calm down! I am not a fan of the jab aircraft myself, but that is just my opinion. Doesn't mean I need to come on a forum and whinge about it like a teenage girl. when it comes to mechanical and safety issues certainly have constructive conversations about things, but what I have been reading this morning clearly demonstrates why I refuse to call myself a pilot and just tell people I fly aeroplanes. we are all mature adults on here, we have to be to fly. lets act like it.its like they say, "pilots, looking down on people since 1903!"

Best have a good cry, and then go back through the forum for bigger threads that contained much more detail and hard facts, and hopefully you'll be happy that the discussion is based on firm grounds.

 

 

[Sapphire]

I know the quick method to deflate the Continental lifters but don't know how reliable it is. All the info I got is from the published Continental bulletin available free on the internet. What I put in my post is from that bulletin. The issues regarding the Jab sound valid based on my experience. They have improved the engine but it is still not acceptable. Seen a brand new Jab need top end replacement after 350 hrs and the pilot was very conservative and had it serviced by factory trained mechanic. Another Jab in the club had this done even more often but the pilot used two throttle positions-idle and nearly full bore. If you buy the machine, don't grumble-it was your choice.

 

 

[Phil Perry]

I have been reading over this forum, and the mechanical and Jab issues aside, I am disgraced by the hostility and plain b*tching i have been reading. first of all guys calm down! I am not a fan of the jab aircraft myself, but that is just my opinion. Doesn't mean I need to come on a forum and whinge about it like a teenage girl. when it comes to mechanical and safety issues certainly have constructive conversations about things, but what I have been reading this morning clearly demonstrates why I refuse to call myself a pilot and just tell people I fly aeroplanes. we are all mature adults on here, we have to be to fly. lets act like it.its like they say, "pilots, looking down on people since 1903!"

Hi Tim,

 

I have to say that I've found this thread quite interesting, Oh sure, you are going to get some folk who will get a little heated, some with good reason, but as you know, the BIG problem with TEXT MESSAGES is that they really DON'T convey anything other than words, which of course can be interptreted as you will. I personally wouldn't agree that there was any "Bitching" as such, but I DO like a good argument, PROVIDING it isn't too silly. that's what makes life interesting. Incidentaly, my Daughter Rachel, whilst 16 years old, used to carry out a 100 hourly maint. job on my Rotax 503, including removing any carbon deposits. She then replaced the gaskets and put it back together and torqued up everything correctly. She insisted on being there when it was check flown. She then got a boyfriend ( who DOESN'T LIKE FLYING !!!! ) and lately I have been forced to do the damn job myself.

 

Stay cool

 

Phil

 

 

[motzartmerv]

There is some very goo info and discussion in this thread. It's pure gold that someone complains about the bitching and then in the same breath calls people teenage girls.. Lol... Hello pot, the kettle is calling again.. Let the robust comments continue I reckon, at the end of the day we are mostly all mates and can handle the blues.. Harden up and speak up is my motto :)

 

 

[ausadvance]

I have been reading over this forum, and the mechanical and Jab issues aside, I am disgraced by the hostility and plain b*tching i have been reading. first of all guys calm down! I am not a fan of the jab aircraft myself, but that is just my opinion. Doesn't mean I need to come on a forum and whinge about it like a teenage girl. when it comes to mechanical and safety issues certainly have constructive conversations about things, but what I have been reading this morning clearly demonstrates why I refuse to call myself a pilot and just tell people I fly aeroplanes. we are all mature adults on here, we have to be to fly. lets act like it.its like they say, "pilots, looking down on people since 1903!"

regarding my earlier comment, I am certainly not disagreeing with the info that being put out, infact I have taken quite alot from reading, what i don't like to see is the way its been put forward, having digs at people when trying to put your information across only results in them closing there ears to your opinion and not taking on board what you have had to say. though I must say admit in the later replies to this thread, things did cool down alot, but my view, and I think the view shared by many others was in the beginning, the conversation was quite a bit out of hand.

 

 

[ausadvance]

Hi Tim,I have to say that I've found this thread quite interesting, Oh sure, you are going to get some folk who will get a little heated, some with good reason, but as you know, the BIG problem with TEXT MESSAGES is that they really DON'T convey anything other than words, which of course can be interptreted as you will. I personally wouldn't agree that there was any "Bitching" as such, but I DO like a good argument, PROVIDING it isn't too silly. that's what makes life interesting. Incidentaly, my Daughter Rachel, whilst 16 years old, used to carry out a 100 hourly maint. job on my Rotax 503, including removing any carbon deposits. She then replaced the gaskets and put it back together and torqued up everything correctly. She insisted on being there when it was check flown. She then got a boyfriend ( who DOESN'T LIKE FLYING !!!! ) and lately I have been forced to do the damn job myself.

 

Stay cool

 

Phil

mate I will certainly give you the credit in what you said before, you are right and forums do not convey anything other than words leaving alot to how one perceives how the conversation is really going. reading back through I think I felt alot more aggression when reading the posts this morning than I did re reading them now. and i would also like to make it clear that i really do feel merv has every right to be furious at jab for the problems he is so regularly having. what i was concerned about seeing unfolding was what i saw as the aggression toward each other. and i do feel that the way many messages were put across could have been done in a far more constructive manner.

 

 

[Guest Maj Millard]

Timbo, facts are facts mate, and sometimes pretty just doesn't enter the equasion. A lot of people have been watching these engines now for a long time, and are still waiting for regular failures of the same components to cease, or at least be reduced to match other engines in the arena...........If you want pretty, and nice, how about this : Friends don't let friends fly with Jabirus engines!! ...........................................................Maj...

 

 

[ausadvance]

I couldn't agree more Maj, i personally have been involved in 2 incidents involving jab engines, this is not what i have been talking about. all i was saying was the way it was communicated between each other. it is just such a shame to see anger between " recreational pilots" just takes away the recreation in it if you ask me. It was in know way the mechanical side of things i was referring to. i just feel a few people jumped to hostilities toward each other a little to early. anyway I have said my peace i will leave it at that.