CASA - Draft Proposal for Jabiru Aircraft

[DWF]

I am out for dinner with Corrine, it's her birthday, and as I can't see the post numbers on my phone I will check in the morning

Ian. You shouldn't be monitoring the forum on such occasions.

 

It's definitely not the way to win brownie points!

 

 

[gandalph]

Something doesn't have to be broke to be improved. It's happening all the time. The logic of your statement eludes me, gandalph. Do you really stick by it?. You can tell me, I won't tell anyone.

Nev, that was my point. I guess I just put it very poorly. Apologies for any confusion. It's been a long day.

 

 

[gandalph]

You're a bit of a worry gandalph, why not just leave it.

Thanks Turbs, Good advice is hard to come by.

 

 

[cooperplace]

I am out for dinner with Corrine, it's her birthday, and as I can't see the post numbers on my phone I will check in the morning

wish her a happy birthday from everyone who flies

 

 

[jetjr]

What is the typical weight vs hp on common GA aircraft, even 912. Keep it in mind that even other options limit aircraft weights. Owners pocket will be lighter I guess.

 

Sorry guys I ll let you fly 20 hp short, CS prop or not, they arent majoc.

 

As mentioned 914 doesnt carry bulletproof rep of smaller brother and they are horrible price and heavier esp if IFA prop needed?

 

Not trying to run down what you have just that theres always compromises. $$$, vs kg vs risk.

 

 

[robinsm]

Thanks for the clarification Ian.I, and many others here appreciate the value of this site and the effort that you and the moderators put into maintaining the standards even though some of us may get narkey about some of the editing that takes place.

 

The bottom line is it's your site and you set the rules.

 

I just wonder about post #441 in the "Yet another jab down" thread. Seems to me to contravene rule 2.5 pretty comprehensively. I understand the frustration in that post but leading by example would have been a better option in my opinion.

Sorry gandalph, the man owns the site, he can do as he pleases. I think you comment is way out of line and you owe the man an apology. He is allowed to get upset every now and then, after all, he funds the site and keeps it running.

 

 

[bexrbetter]

So why is it not as reliable as like engines in 2014..that is the question ?.......

Evil TVs. ... and I don't mean Home and Away.

 

He is allowed to get upset every now and then,

I'm surprised we get the rope we do some days!

 

 

[deadstick]

For those interested and comparing the 914 Rotax to the 3300 jabiru, the rotax's is going to eat the jabiru at just about all power output points. Example, j230 medium or low density altitude at takeoff power, the HP curve at 2800 rpm ( which is what you will see in a 3300) is below 100hp same aircraft and DA but with the turbo Rotax, the turbo compensates for most DA performance loss and performs better right through the altitude ranges. Add in an adjustable pitch prop and you have your self 115 hp from takeoff to let's day 10k feet. Adjustable pitch prop on a 3300 and you may see 120 on takeoff but not for long as you climb. The hp figures for the 3300 are at ISA conditions and spinning at 3300rpm so who ever see's 3300 rpm on takeoff?

 

 

[dmech]

Fuel, interesting and always comes up as a possible cause.Our first through bolt popped on an engine that had spent 100% of its life on AVGAS.

I accept that someone may be very unlucky and get a carby full of dodgy fuel. Maybe, once in a blue moon. I know it doesnt have the same regulation of AVGAS, but the higher quality fuels should be ok, after all, people put it in cars worth much much more than our little jabirus's. Imagine the uproar if a bad batch caused the destruction of a few mercedes and a couple of porshe's.

 

The engines we have run on high octane mogas look so much better when stripped, no lead deposits, nice charcoal colour instead of grey. What is the mod required to Lyc engines to allow them to run on Mogas? I know it aint bigger through bolts and liquid cooling:)

yep its the fuel ! if the engine didn't have fuel it would nt snap bolts

 

 

[dmech]

Can anybody inform me which thru bolts are the most common to break ie. upper or lower and on which side of the engine , any bolt size. Just doing some research on this.

 

thanks

 

A.D.

 

 

[microman]

An an NZ'er watching this thread with interest, I note some of the comments on the Rotax 912's in relation to their maintenance issues and repair costs. Yes, parts are expensive - I just had my gearbox completely rebuilt at a cost of approx $3500, but that was after 1500 hours, I also had the carbs rebuilt ($500), but the replacement hoses only cost $200 and I did them myself. Unless its an LSA you dont always have to use genuine Rotax parts - there is lots out there which will do the job perfectly well. Apart from the occasional problem with ignition modules, and sprag clutches, often at around 500 hours, nothing much else seems to need attention - they just keep going. There are around 90 microlights on our field and most of them are Rotax- engined. If anyone ever turns up with a Jabiru we all say a prayer for him and implore him not to take any risks. All this talk of special treatment like avoiding sustained power climbs and not risking mogas seems laughable to anyone with a Rotax - we all use 95 or 98 in our 912S's and never a problem - the 912 of course is happy with 91 octane.

 

 

[ianboag]

Bit of thread drift going on here. I have been part of it and apologise.

 

912's last longer than Jab engines, but this is not what the thread is about.

 

If CASA gets its act together the next thing would have to be be some specific deliverables for Bundy to meet. I would wager a reasonable sum that noone in CASA has any concrete idea what these targets might be or how to monitor compliance with them. The deliverables would be "to make Jabiru fix their engines so they break/wear out less often" and compliance would be deemed to be a state where that is "observed to happen". I would guess that CASA has never done a job quite like this before and CASA probably does not have the skills to do anything useful in this poorly-defined furball.

 

I would also guess that the stats we have seen are about as useful as the proverbial knob of goat dung. If I have an early top, or replace a broken flywheel bolt or two, or lose leakdown because of gummed-up rings, or even if my engine sucks a valve, there is no obligation to report it to anyone. Bundy is often less than helpful to those who pass the word back ...

 

Personally - I find some of the engineering stuff a bit bewildering. Through bolts pop because the joint they are securing moves and bending-back-and-forth fatigue snaps them. That is how clamp joints fail ... always ..... The only real answer for an under-performing clamp joint is "more clamp force". Bigger and/or better bolts .... Ditto with flywheel bolts.

 

The extensive use of Loctite 620 seems to be a peculiarly Jabiru thing. Lyc/Conti procedure is to oil the through bolt threads before assembly and torquing. I am told by friends with metal-bending experience that dry torquing is a nono. Go figure.

 

I believe the engine could be made into something that lasts longer and breaks less. If that made it a bit heavier, so be it. And now Camit is making a better-Jab-that-is-not-a-Jab, but regulatory, IP and inter-personal issues cloud its status. A farcical situation where some heads should be banged together. Some of the heads to be banged should be CASA ones.

 

Disclaimer : I'm a Kiwi who flies a microlight in NZ so none of this has any regulatory impact on what I do. I'll leave now :-)

 

 

[vk3awa]

Can anybody inform me which thru bolts are the most common to break ie. upper or lower and on which side of the engine , any bolt size. Just doing some research on this.thanks

A.D.

Add to your research.....which generation engine. Hyd/solids lifters/cam/hollow or solid push rods... et cetera The point is, there have been a lot of changes in the "evolution" of Jabiru engines. In my experience the solid lifter engines did not appear to have through bolt failures. The early broad fin heads had cooling issues that could be somewhat managed by the operator. With the introduction of the hydraulic lifter engine came new issues. These issues have been highlighted by Jabirus recent statement.....through bolt failures and valves sticking in valve guides. Now there have been changes along the way of the hydraulic lifter engine .....3 (or more) cam changes, 12 point nuts, larger through bolts, pistons with valve relief to name a few. Have these changes been made as a bandaid treatment or to cure root causes of ongoing problems.....? I don't know I'm asking the question for those that have more knowledge than me.

 

 

[vk3awa]

Personally - I find some of the engineering stuff a bit bewildering. Through bolts pop because the joint they are securing moves and bending-back-and-forth fatigue snaps them. That is how clamp joints fail ... always ..... The only real answer for an under-performing clamp joint is "more clamp force". Bigger and/or better bolts .... Ditto with flywheel bolts.

Hey Ian....I think you get it.

 

 

[Admin]

But that thread has now been locked.

Only locked whilst it was cleaned up...have a look

I owe an apology here because I must have forgotten to open the thread again, I am sure I opened it back up again but anyway it is open now

 

I just wonder about post #441 in the "Yet another jab down" thread

Ok, that post was warranted and did not single a person out and yes, I can throw a dummy spit when I see my hard work being trashed, but then I too am also at the mercy of the moderators who have on occasions moderated me. The bottom line is if I don't like seeing and reading the site any more then I will pull the plug and I hate seeing us all attack each other especially in such important threads as this one and that other one. This site can not, and will not, be biased in any way in these kind of issues however it is, and always will be, biased towards safety for you and me, our families and friends

 

 

[Admin]

PS...Corrine says thanks for the birthday wishes, sorry to go off topic

 

 

[Bruce Tuncks]

There was a guy who burned his new Jeep on TV recently, and I have considered doing the same with a new Massey-Ferguson tractor. Yes we went down the legal path with the tractor ( including VCAT ) but it only wasted more time and thousands of dollars.

 

In comparison, the Jabiru has been completely reliable and well-supported.

 

Anybody wanna buy a near-new 6400 series MF for half-price?

 

 

[deadstick]

Ianboag, hi mate there's a couple of causes of through bolt failure. First is quality control:- I received a batch of the new 7/16 through bolts to find a clear stress raiser on the machined neck of one, another had the thread formed strangely. Second:- the nut riding on the radius of the base flange for the barrel and placing a side load on the bolt. Third poor assembly at the factory causing chaffing of the case halves and them hammering on the bolt, I have seen locating dowels fall out of case halves when split on low time engines. Fourth I suspect there is a resonant frequency being generated, some times you can here it:- flywheel bolts fail not from shear ( flywheel still located on dowels) but just snap at the base I suspect due some form of pendulum effect hammering through the crank.

 

 

[fly_tornado]

Bruce, you seem to be ignoring the fact that many are having issues with Jabirus.

 

 

[Russ]

F-T.......my read is Bruce has good experience with his jab, that's it, period.

 

Why you came back with ????? Puzzles me.

 

 

[turboplanner]

The reason for coming back Russ is that is one aircraft only, and the action take by RAA and CASA is based on a lot more numbers, and more importantly, forced landings which is the safety issue.

 

The owner of the aircraft which was damaged in the forced landing at Red Cliffs, had had 8 years reliable service....until the engine failed.

 

RAA have the reports which give the number of forced landings and that is the key figure for safety.

 

If engine issues were just being found on the ground, or gave signs before failure, then it would just be a financial matter between supplier and customer.

 

Several people have pushed the single reliable aircraft story, but it's statistically irresponsible.

 

 

[Jabiru Phil]

For those interested and comparing the 914 Rotax to the 3300 jabiru, the rotax's is going to eat the jabiru at just about all power output points. Example, j230 medium or low density altitude at takeoff power, the HP curve at 2800 rpm ( which is what you will see in a 3300) is below 100hp same aircraft and DA but with the turbo Rotax, the turbo compensates for most DA performance loss and performs better right through the altitude ranges. Add in an adjustable pitch prop and you have your self 115 hp from takeoff to let's day 10k feet. Adjustable pitch prop on a 3300 and you may see 120 on takeoff but not for long as you climb. The hp figures for the 3300 are at ISA conditions and spinning at 3300rpm so who ever see's 3300 rpm on takeoff?

Could be a problem here.

 

I get 3000- 3050 at takeoff with full fuel.

 

Phil

 

 

[Russ]

Turbs......I acknowledge a lot of jab owners have some horror stories, genuine lack of customer support as well. Bruce is just saying " he" has had a good run, as many others have had a good run.

 

Linking that to he and others in denial of the jab failings, is drawing a long bow.

 

Often....often, I read of great excursions all over/ around Oz, blistering hot locations at times, all done by very happy jab flyers, and keen to find their next sortee,

 

Can't recall at the minute, of multiple stories of non jab flyers doing similar trips.

 

I own a jab, I've done a few " tiger " runs, all good so far, more to come, that lurking thought of engine failure is there, and I don't like it. Attention to precise engine condition is paramount, before we head off, as is heat management enroute.

 

Increasing my lower cowl lip, has made a huge difference to temps. And running upper cyl lube....I think helps as well.

 

 

[rankamateur]

Anybody wanna buy a near-new 6400 series MF for half-price?

We bought a new MF 1100 in about 1968, kept us too poor to buy a green one for many years, got green ones now!

 

 

[nomadpete]

PS...Corrine says thanks for the birthday wishes, sorry to go off topic

Ian,

 

I know it's late, but please wish Corrine a Happy Birthday for us.

 

I'm sure I speak for all forum users when I say a big thank you to Corrine for her support of your work on this valuable resource for us.

 

Peter