Oscar

I used to do some car racing - a sport most people consider to be vastly inherently dangerous and taken up by those who had a desire to be nothing more than temporary Australians. I built what I drove, so I had both sides of the desk covered, as it were: my own driving and my mechanical ability / stupidity.

 

I can't readily think of a group of people who exhibited more concern for being 'their brother's keeper' than (most) of my fellow racers. They'd hand out tips and advice (and sometimes quite trenchant criticism) of one's driving, and they'd provide a vast amount of useful advice on how to do the mechanical side safely and competently. The officials not only checked out the mechanical condition of your car, but even checked out that you were properly strapped in ( no loose straps, belted in as tight as..) before you were allowed out on the track while you were sitting in the pits on the exit lane. Once you realised that these people around you genuinely did not want to see your blood spattered around, not have theirs endangered by your driving or your vehicle in extremely close-quarters edge-performance situations, the advice and attention became a most welcome 'second set of eyes'.

 

As for the adrenalin rush thing - in fact, motor racing is the most intense application of self-control I have ever experienced, and you absolutely learn to keep on making judgements, correcting for changing situations etc, on a fractional-second basis - there is absolutely no room whatever for indulging in 'HOLY Shit' and freezing at the wheel while the situation rushes at you and becomes an accident rather than a 'moment'. That sort of forced clarity of thinking comes in handy when you find yourself landing in a glider when the wind has changed 90 while you were on base, and you find yourself touching down on one strip with a fellow glider touching down on the cross-strip and you're both headed for the intersection and going to arrive there simultaneously.. or having the rudder pedals shoot forward out of their lock and out of your reach as you turn final and have some idiot start to walk his glider across your touch-down point...

 

 

Wow - a lot there to contemplate!

 

I think that the Jaba Chat stuff I posted above explains what Jabiru MEAN when they say 'run it hard'; let's be realistic, 'run it hard' is not a technical specification for operation but a very loose term that lacks any sort of quantification. It's a bit like 'torque it to really bloody tight' or 'belt the crap out of it', isn't it? Rod Stiff just may have unwittingly condemned lots of his engines to an early grave by using a term he thought would be understood to mean one thing but has (not unsurprisingly) been taken to mean something else! The POH (at least for the J120) certainly provides a far more definitive specification for normal engine operation in climb and cruise modes, and I think it's not unreasonable to suggest that that Jaba Chat explanation exists because Jabiru realised they needed to provide a batter explanation of things than just a three-word slogan. There's an old slogan that goes something along the lines of: 'I know you heard what I said, but I am not sure you understood what I meant' - and surely Jabiru published that explanation because they realised more explanation was needed. Rod Stiff is a man of mostly few words, and possibly in this case, a few too few!

 

As for the piston direction thing - I've had the geometry involved explained to me and I'm certainly one of those that believes that the Jabiru piston install direction is incorrect. It's a fairly simple case of looking at the line of force reacted by the downwards-travelling con-rod when projected through the crown of the piston at peak combustion pressure loading, and you can see why a gudgeon-pin offset helps to keep that line of force in the centre of the piston thus holding it straight in the bore (or perhaps more accurately, why an offset gudgeon pin placed on the wrong side will increase the rocking force imparted by the combustion pressure on a piston where the line of force reaction is off-centre) thus driving the piston skirt and crown against the sides of the bore. Changing the piston install direction around to 'normal' isn't a silver bullet thing as suggested, but one of a number of incremental changes that are entirely likely to be beneficial.

 

 

I agree we shouldn't lump Camit into the Jabiru problems.

OK! - we have a point from which to move forward. Can we agree that:

 

1) if the statistics demonstrate that there is a problem of sufficient magnitude in terms of user safety, RAA should take whatever action is appropriate to maximise user safety;

 

2) that RAA is the appropriate authority - rather than the 'court of public opinion' ('aka forum threads') for the delivery of whatever 'evidence' - be that authoritative analysis by reputable entities or personal opinion - that ought to be considered;

 

3) that discussion of potential changes to the existing situation constitutes exchange of information;

 

4) that statements purporting to convey a summary or statement of expert opinion/extrapolation of 'fact' from anecdotal / published sources without the supporting evidence are a waste of everybody's time.

 

Let's strip away the bias, personal prejudice etc. and provide as much fact / information useful to establishing fact, for the users / potential users of Jabiru engines as we can assemble. For instance: I won't claim that the through-bolts issue is dead and buried until there is a statistically reliable source for making such a statement. Will you refrain from claiming that through-bolt failure was the cause of an engine failure without being able to document all the circumstances of the engine in question that MAY have caused the through-bolts to give up and shown that it was, in fact, an 'unprovoked' failure of the bolts, not e/g. operating outside limits? This is important stuff.

 

 

You're assuming that the prevalence of engine failures has no impact on RAA activities.

OK., how about you and I hold fire on our differences in the interests of the greater good here? I'm prepared to come out of my trench in the Christmas Truce situation..

 

Are you saying that RAA activities have been - or should be - impacted by the statistics of Jabiru engine failures? It's a fair question - but surely that is something that RAA needs to answer, since it is the only authority with the full access to the statistics. Are these reputed failures of sufficient impact that something really radical should be done? I'm happy to acknowledge that RAA has had a lot on its plate in simply trying to sort out the registration mess - but is it in fact the case that Jabiru engine failures are causing deaths/injuries at the rate that needs specific RAA safety focus? That's a question that RAA should answer, officially - not just as a casual comment. How about we ask them directly? How about you pose that question to the new Tech. Manager? Let's have it all out in the open, rather than one side hurling invective and the other side postulating 'no serious problem'.

 

How about we both work to improve the information available to prospective users of Jabiru products, rather than beat our own specific drums? Just where on the scale of safety / economic problems do Jsbiru engine failures rank - and what are the real causes of those problems? What are putative solutions to those problems and how reliable are these?

 

If the occurence (let's walk away from the emotive-laden 'prevalence' word in the absence of quantitive analysis of failure rate/hours flown data for now, ok?) of Jabiru engine failures moderated by the discovery of actual causes is impacting the activity for RAA - let's hear all about that. Let's have the damn factual evidence. Anything less than that is really nothing more than false advertising for/against the product.

 

 

Russ, I think that just about anybody involved in Recreational Aviation in this country - even those who harbour a deep-seated antipathy towards anything Jabiru - would admit that without them here, we'd be a far less successful sector of aviation. They're a bit like Commodores /Falcons / Camrys - they're not the BMW's, Mercedes, Porsches of the sector, but when you want to haul the family on a holiday instead of run down to the local social hot-spot and be seen as cool, they do the damn job - and they do it pretty well. You can (if you treat them half-reasonably), pretty much pack everybody in, head off to the destination and have a reasonable expectation of arriving there when you expected to. And if they do hiccup on the way, then there's somebody around who can get you back on the road again before your holiday is ruined.

 

Yes, CAMit and Jabiru are headed on different paths regarding engine supply for Jabirus. Just what the 'Chinese' engine will deliver is something I suspect only Jabiru know at this time - we'll all have to wait and see what that is, in the experience of real-time use. We all have no idea of not just performance but even price! Will it be a simple retro-fit for existing engines? You'd have to think yes, it would be - but again, that is something we don't yet know.

 

CAMit are not building an engine based on the idea that it will replicate a Rotax. I am one who welcomes that; I have deep-seated reservations about using a basic reciprocating concept that depends on a crankshaft manufacturing technique that has grown from small, short-life two-strokes in a four-stroke environment. I'm happy to acknowledge that that is a prejudice reinforced by the knowledge that there are no high-performance four stroke engines that use this form of crankshaft, from heavy-equipment diesel engines through to ultra-high performance drag racing engines. That said, I recognise that - generally speaking (though the recent Rotax emergency bulletins effectively recalling a large number of crankshafts is a bit of a reality check) - Rotax engines are a decent thing. I'm looking forward to flying a unique aircraft powered by one - but just personally, I don't want one turning the prop of the device I'll be using as a commuter between my place and another location 1,000ks away over some tiger country.

 

What CAMit are currently developing, is a potentially better Jabiru engine. That it IS a better engine will be either proven or negated by real-time testing - and that is happening right now. Real-life operational results are coming in. If you have the interest to research the changes CAMit have made - they can tell you what, why and how those changes work. Absolutely nothing beats going to the source - and if you have/can create the opportunity to go to CAMit and see, feel, examine, discuss those changes, you can make up your own mind with the real dirt under your fingernails from pretty much forensic-level investigation. To me, that just HAS to be worth the time and expense - and in our case, we drove something like 1500k's one-way, spent two weeks (copping the accommodation charges), and got not just dirt under the fingernails but several days of full-body kerosene wash just from cleaning our old engine ready for the upgrade work!) And the prawns available in Bundaberg from the local fisherman's co-op make any trip there worthwhile.

 

All of that was more than worth it for us personally - because we are both techo-nerds, we wanted to know all the nitty-gritty. I personally find the PR blurb for engines and aircraft to be so much marsh-gas - call me an old-fashioned cynic, but for me two weeks of exposure to every little detail about the manufacture of an engine from a lump of metal through to a delicate finished component beats two paragraphs of web-page blurb. About 99% of my own flying experience has been in aircraft in which I absolutely knew that engine failure was not going to happen - because it didn't have a damn engine. And,yes, I've outlanded in paddocks surrounded by trees and infested with cows..

 

A visit to CAMit is phenomenally instructive. Next best is talking to them. They are there, on the end of a phone call/email. You don't have to just pay your money and see what happens.

 

 

Jabiru recomend to run their engines hard, that is cruise at 2850rpm, they say do not baby the engine. I tend to run my engine at lower revs and tend to baby it. Can't really see why the engine should be run hard and the gumming rings thing is not a good reason or using Avgas to burn lead off plugs. As using a different oil and Mogas cancel these problems. Using fuel to cool the engine does not seem to be the case either. I know someone who has run several engines to TBO, doesn't run them hard and uses non aviation oil. Any thoughts ?

Seriously - and not wishing to be in any way combative - is the 'run hard' and 'don't baby it' thing more conventional wisdom handed down from person to person than actually what Jabiru says? I can only comment from the J120 POH, because that's what I have access to, but those terms don't appear in it - and there's really nothing about engine operation that suggests it. They're both very subjective terms anyway!

 

However, here's some quotes from the 'Jaba Chat' of September 2011 that might provide a bit of perspective on what Jabiru actually are saying - and some of it is worth reading carefully, because they are fairly comprehensive explanations of a difference between 'run it hard' as most might interpret it vs. 'let it spin freely':

 

CLIMB OUT SPEEDS

 

There appears confusion on best climb out speeds. Manual specifications for best rate of climb

 

for J160 and J230 is 68 and 75 knots respectively.

 

This means this air speed will give the best chance of clearing obstacles if the need arises.

 

However the rate of climb for best engine management has been largely left to operators.

 

The quickest way between two sets of traffic lights is to floor the accelerator and race the engine

 

– but it’s not the way most of us do things because we understand that driving that way will use

 

more fuel and wear the engine out faster. Similar arguments apply to climb speeds with a Jabiru

 

Engine. The 4 cylinder engine will look after you better with better air/oil cooling if climbed around

 

80 knots while the 6 cylinder will think highly of you at a 90 knot climb or above. If flying a J430/

 

J450, climb speeds for load will differ especially according to load. Once heading to that cross

 

country destination cruise climb at elevated speeds (shallow angle of climb) contributes to good

 

engine management. At these higher speeds not only is there more air available to cool the engine

 

but the RPM is higher, allowing the engine to rev more instead of “lugging”. This significantly

 

reduces the stress on the engine and makes it less likely to suffer detonation or other

 

long-term maintenance issues.

 

 

 

OPERATING RPM

 

Historically we have always recommended that operators allow their engine to rev rather than

 

lug. Done properly this approach works very well, however in certain cases it can also be damaging

 

as it has been over-simplified and does not necessarily consider percentage power.

 

For example, consider a Jabiru J200 with a Jabiru engine, propeller and cowls. In a full power,

 

straight and level run at sea level this aircraft should reach speeds in the 130 – 140 KIAS range

 

and the engine will be revving to around 3100 – 3200RPM. In this aircraft – which is fairly sleek

 

and fitted with a well-matched propeller – cruising at 2900 rpm is fine because it will be at a relatively

 

low power setting.

 

In comparison, the same engine and propeller could be fitted to a bush plane with slats, flaperons,

 

tundra tyres and the aerodynamics of a brick. In this case the static RPM and RPM on takeoff

 

would be similar to the J200 – but flat out straight and level at sea level the aircraft won’t do

 

much more than 100 knots and the engine will be stuck at about 2900 – 3000 RPM or less. In

 

this case trying to cruise the engine at 2900 RPM would be disastrous as it would be a very high

 

percentage power setting.

 

The above examples are deliberately extreme but their message can be applied across all airframes

 

and engine models.

 

It's not like keeping a diesel engine under decent load to avoid glazing the bores! What Jabiru are saying, basically, is: let them rev decently, don't beat them to death. It's not difficult to see that this is quite different to 'use

 

them hard' - if 'use them hard' is taken by the pilot to mean 'load them up and make them work all the time at the top end of limits'. So I don't think you are 'babying' your engine, but rather using it intelligently! If it's toddling along at lower revs and the CHTs are good - then surely you're giving the engine its best chance of returning you the sort of life you expect.

 

One has to wonder - how many Jab. engines are bought to premature ends because the operators thought they were doing what Jabiru says, based on 'conventional wisdom' handed out by a mate, someone on the field etc. - rather than actually operating them according to the manufacturer's recommended techniques?

 

 

Oscar, all this has got me excited, especially"...an inhibiting set-up that allows you to (very easily) squirt a shot of hot engine oil into each cylinder after shut-down, better than twice the alternator capacity..."

Can you tell me more about this oil squirt system, as I was about to bodgy up some way to squirt lube down the carby throat before stopping the engine.

 

Regarding CAMit's extra alternator, why would it be needed if the recent Jabiru winding modification worked?

I would - as Dafydd as suggested - absolutely and unequivocally suggest that anybody who is interested in any of the CAMit mods, contact Ian Bent to discuss them. That way you'll not only get the full skinny on what is done, how it is done, what material and process is used and all of those questions you'd probably want to know about, but also how it all fits with the overall 'system' that is the engine - i.e. what might be termed, rather badly on my part, as 'secondary effects'. Something we found while we were at CAMit is that for many of the changes, there was more than one good reason for choosing the design, material and methodology. The new through-bolts, for example, have been developed not just for additional strength, but also for their utility in improving case-pinning, the type of nuts used and the threading for them etc. - but also for their harmonic characteristics. Yep, through bolts can - apparently - vibrate at certain harmonics, affecting their performance! CAMit's through bolts go in one way only to the cases, though the difference to look at is very subtle (ask me how I know about this...or have you already guessed..? Suffice it to say that CAMit, having watched us do it incorrectly first time, now add a 'this way around' indicator on their new through-bolts... having observed that no matter how fool-proof you thought your dooberry is, there's a more inventive fool than you thought about out there lurking. It's kind of reassuring when, encased in the pink cloud of acute embarrassement, you not just hear people saying 'well, you wouldn't be the only person to make that mistake' but see 'that mistake' positively addressed..)

 

The new alternator, as Dafydd says, not only provides more and 'cleaner' power but adds some harmonic balancing to the flywheel. You might not need the extra output, but I seem to remember a thread on here regarding iPads catching fire (??) that seemed to conclude that the car-type alternators were a better bet (electrics isn't my strong point..) and I imagine that if you were going to run LiFePo4 batteries they might be a better source of in-flight charging power too - but let's not open another front in the electronic war on here if I'm wrong, just say: 'nope, that's incorrect'.

 

WRT the inhibitors - and again, Ian Bent is your man to explain the things in proper detail - they are a very fine, almost hypodermic-syringe needle size insert in the inlet tract for each head. Each cylinder gets a wee squirt of hot engine oil. You have to have the heads drilled to install them, and that means removing the heads and using a (good-quality!) drill press and the special guide jig (CAMit made one up for us because our heads are almost the first-type used on 2200s and have the narrower rocker-cover bolt spacing, where the jig bolts to ) but I think you'd like the way they have been designed to operate, it's rather delightfully elegant. I imagine CAMit have closed down for the end-of-year break, but it could be well worth the wait to talk to them (though what you were thinking wouldn't in any way preclude doing the CAMit mod later, I'd have thought.)

 

 

Right on the button - except I understand CAMIT also have a kit to convert hydraulic lifter engines back to solid lifters.

Yes, CAMit does. I've seen the communication from a US user of that kit saying that he'd like to come out to Australia and do (something intimate concerning his lips and their backside) for the results he's had from installing it...

 

 

JJ - that's a pretty complete list, though I don't think there is a new oil catch can and drain, and I'm not sure you'd call it a new head design, rather new rockers (much easier to adjust accurately and quickly, far better geometry), rocker bushes and a bit more to come (work in progress when we left). Certainly better oil pressure regulation AND thermo cooling control (the latter still under final testing), improved harmonic balancing for the flywheel end to improve flywheel bolt life, an inhibiting set-up that allows you to (very easily) squirt a shot of hot engine oil into each cylinder after shut-down, better than twice the alternator capacity, top-quality spark leads and coils with epoxy potting of the LT lead into the coil. Yep, stronger cylinder barrel bases, through-bolts and nuts and a civilised case joining technique that can't degrade under use/abuse and start the whole through-bolt failure dance. Some subtle changes in certain critical tolerances that are tailored to air-cooled engine operating characteristics.

 

If you like that lot, there's another quite significant 'tweak' that I think you'll really like (that is so far showing under testing to have a good effect on lowering CHTs) - but I'm not CAMit's PR person and it's not my place to talk about it, but that will I am sure be announced when CAMit is happy to do so. Suffice it to say that with it in place, you can shut down your engine and immediately pull it through quite easily rather than the usual 'tight' condition.

 

Yes, obviously I'm enthusiastic about what we've seen and incorporated into our engine - but what the hey, I'm just shooting so much hot air, apparently... but we'll be putting CHTs and EGTs on all four cylinders and recording the results when our beastie is back in the air. CAMit is not in the business of claiming anything that won't be backed-up with proven results; we are happy to be testing candidates.

 

Of course, and as you say, any success on the part of CAMit to improve the reliability of Jabiru-based engines would pretty much destroy the apparent leitmotiv of some contributors to this forum. Who was it who said 'you can't please all of the people all of the time'?

 

 

As an (obvious) Jab supporter - with due circumspection - I'd have to more than agree that any Jab engine is a poor match to a Storch. If that's a Slepchev Storch then the only thing I'd personally fit to it would be a basket to hold the kindling, but that's a different issue.

 

However: if the oil cooler just kept cracking - then surely you would have to agree that it's an installation problem? Even those rather cruddy Repco-supplied coolers generally didn't fail repeatedly in the original Jabiru installations (and I think they were pretty rudimentary and not very efficient, based on what was in our aircraft - but they did the job, sort of.) I don't think one can reasonably damn the manufacturer for problems caused by installations outside of their control.

 

 

Alan - I'm neither trying to be a smart-arse here nor sell you a Turtle-pak, but if I were thinking of this flight I'd be looking into making it 'legal' all right (and an EO will almost certainly demand LAME installation) - I think you may find that you'd be breaking all sorts of rules (some of them with not insignificant penalties) and almost certainly voiding your insurance cover otherwise. And, if you recall the Pel-Air crash background information that came out, Norfolk Island has a notoriously changeable weather situation, you do NOT want to be without adequate fuel for a diversion - and there aren't many options way out there. If I read my Google Earth properly, you need rather more than 20 litres extra to divert to Lord Howe if Norfolk socks in, or to Australia if Lord Howe exceeds max. crosswind!.

 

 

Not on the 3300. Mine is the new model with roller followers etc & the sump is finned. See attached pics. I also have a 7 row Positech cooler with a separate airflow via a NACA duct in the lower cowl so if I have any problem with oil temp being too low I can restrict the airflow easily by installing a butterfly valve. There is a 250mm sealed tunnel from the back of the duct to the cooler. I spent a fair bit of time reading various documents on cooling air cooled piston engines starting with the 1981 NASA report 3405, some EAA articles etc & found the information very valuable. Getting the airflow right is one of the most important aspects of maximising the life of your engine. The big cooler & long oil lines from the engine will probably add around 1/2 litre to the total oil capacity.

My apologies - I haven't spent much time looking at 3300's! Strange that Jabiru has retained the finned sump, maybe just hasn't re-done the casting (the presence of fins is in no way a problem, it just does sod-all for cooling the oil..) That Positech should do the job a treat.. and by not having introduced high(ish) pressure air into the lower part of the cowl from the oil-cooler air dump side, you're certainly doing your heads and barrels cooling the best possible favour. That's a very nice looking install - we're trying to clean up the one in our ST1 but I don't think we could get it half as neat.

 

P.S. you might find it interesting to talk to CAMit about their oil take-off adaptor - could suit you rather well!

 

 

Since it's a J400, then it is VH-reg. Turtle-Pak make certified ferry tanks (a bit larger than what is actually wanted, but the smallest is not very heavy) that are certified and quite often used - and you don't have to fill them right up, of course). It's not at all unlikely that buying one of these and getting an EO for fitting it would be cheaper than any alternative that will require testing etc. for an EO to be issued. My nephew did quite a bit of work with Laszlo on developing aircraft installs (even went to Oshkosh with him to demonstrate then over there a few years ago) and found the products and the company to be excellent quality.

 

http://www.turtlepac.com/products/collapsible-aircraft-ferry-tanks.html

 

 

Jabiru changed from the small 'Repco-type' oil cooler to a five-row (from memory) Stewart-Warner type (and also changed from the finned-sump, that was not successful as an aid to oil cooling) a fair time ago. I think that happened with the introduction of the J160. If you care to do some checking, you will find that some at least operators - certainly of J160s - have more problems with under-temp oil than over-temp oil. I know that, for instance, the J160 on the line at the Darling Downs club has the cooler significantly taped over to get the oil temp up to scratch!

 

There's a thread: http://www.recreationalflying.com/threads/low-oil-temperature-on-cold-mornings.51270/ that discusses the problems of over-cooling of the oil in Jabs., which makes for interesting reading - not just for the reports of over-cooling but some of the sorts of owner responses that indicate how aircraft (in this case, and pertinently to this thread, Jabirus) are used in real life. The first post indicates that the owner regularly flies - in the full knowledge of the POH requirement for oil temp. - not getting to the POH minimum temp 'until about 1000' AGL' i.e. full power off the ground operating the engine out of limit. Same guy spends 10 minutes of idling trying to get the oil temp up - and if he's doing that in cross-wind conditions at a holding point, he's very likely cooking the heads on one side of the engine due to airflow reversal.

 

Or the guy who suggests: "Maybe keep the oil level barely on the stick. Less oil will help".

 

 

I know you weren't aiming it at me but before you start calling someone a goose it would pay to think about collateral damage.In the meantime I'd suggest the title of this thread is a little premature.

The title of this thread is: "major weaknesses addressed." Since you appear to be unfamiliar with the definition of addressed, let me draw your attention to the Oxforddictionaries.com definition of 'addressed':

 

'think about and begin to deal with (an issue or problem)'

 

In fact, CAMit have not only addressed, but with the evidence of results I believe will be able to show that they have redressed, some major weaknesses. Your initial comment demonstrates ignorance of the correct use of the terminology. We will have to await and see if the results of addressing the issues is successful.

 

 

Dr Zoos was quoting ATSB figures.From RAA records showing around 35 Jabiru forced landings between May 07 to March 12 the RAA has provided enough identification of causes to enable manufacturer, maintenance officials and owners to get some urgency into solving some of these problems.

Horseshit. Pure, plain and simple horseshit. The RAA Accident and Incident reports have NEVER stated a 'cause'. They have described a condition/s that was/were believed to have contributed to the incident; they have never published a statement of 'cause'. The actual 'cause' of the condition requires analysis of all the factors that contributed to the condition. For a proper analysis of the 'cause' of an incident, look at: http://www.google.com.au/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&ved=0CCkQFjAA&url=http%3A%2F%2Fwww.recreationalflying.com%2Fimages%2FSmith%2520and%2520Guthrie%2520Finding%2520-%2520Final.doc&ei=87u7UuDyBsjWkgWY64GQCg&usg=AFQjCNGM2DoUc4oFTxfiyw141_kLZuo3DA&bvm=bv.58187178,d.dGI

 

Don't insult our intelligence by purporting to have discovered 'causes', when what you have to report is extrapolation of a summary of 'conditions'.

 

 

"I'm not arguing the facts, merely trying to put pressure on Jabaru to improve their product"....Quote :...Camel...It's nice to have some company, I and others have been trying to do it for at least six years !....The RAA is aware of the need to do something in the interest of safety and the goodwill of their members. Problem is they need solid facts, and lots of them. This is where the membership comes in to provide those concrete facts.....Maj.....

You have made statements regarding what you consider to be 'fundamental design flaws' in Jabiru engines that I have asked you to support with proper, considered evidence; you have failed to so do. I do not consider that to be providing 'concrete facts'.

 

However, what concerns me more is the fact that you - as a member of the RAA Board, for god's sake - wage a relentless campaign of denigration against the aircraft and engines that more than one-third of RAA members own and fly. Even when there is news of a serious effort being made by a reputable company with the expertise, the capability and the commitment to improve the reliability of those aircraft, you relentlessly continue to pursue a path of utter negativity and complete denial that such an effort might be productive, by what amounts to spewing bile towards anything Jabiru or connected to it. You quite evidently seek to destroy any confidence those members, or any new potential members might have, in Jabiru / Jabiru-related products.

 

Given that you are a Member of the Board and have presumed to state an apparent position taken by RAA, I imagine that a legal challenge to some of your commentary on Jabirus might place you / the RAA in an interesting if not difficult position. Exactly what 'something in the interests of safety and the goodwill of the members' relating to Jabiru aircraft and engines is 'the RAA aware of '? Your comment suggests that there is a determination on the part of the RAA to take some action and it is merely gathering facts before deciding on some course of action, as it has a responsibility to do if there is a safety issue. As a Jabiru owner I regard this as an implicit threat to the future operation (and hence the utility and value) of my aircraft. I now place you on notice to provide me, as a member of RAA, with details of what RAA has and is considering, in the form of a response that is similarly public as your statement so that ALL Jabiru owner/operators and any person considering becoming an owner / operator has the benefit of being forewarned as to the nature, extent and possible effects of 'something to be done in the interests of safety and goodwill'.

 

Without the existence of Jabiru aircraft and engines, the numbers of RAA aircraft on the register would be cut dramatically. During the Registration debacle, as it happened, we saw the grounding / severe restriction on the operation of a considerable number of aircraft. Jabirus continued to shift the load of RAA flying - training in particular. As it happened, the majority of aircraft that were grounded / subject to immediate and highly-restrictive limits on their previously-presumed capability to operate (including Ibis, Sting and Pipistrel aircraft) during the Registration debacle were not Jabiru made / Jabiru-powered so a threat to the continued operation of Jabiru / Jabiru-powered aircraft, if it were true, would decimate the availability of capable aircraft for RAA operation as we know it.

 

 

I'm a having trouble following you a little Camel. Are you trying to say that the majority of the problems with Jab engines are the result of Quote : "poor judgement, misuse, mismanagement and poor maintenance" as suggested above ?... Yes I agree all of these symptoms beset all aircraft engines at various times.But can you please explain your lack of mention of :....unplanned low time mechanical failure, or, general lack of robustness of certain critical components leading to sudden, and unexpected engine failure ....IE: valve heads separating from valve stems, critical engine case through bolt failures, and flywheel/ ign rotors separating from crankshafts without warning ?........if I am missing something here please enlighten me................Maj....

Remind me again, if you will, of how many Jab. engines vs Rotax engines have had to be inspected and their crankshafts replaced if within the specified range of serial numbers? Or was Rotax just having a brain-fart when they sent out those several Emergency Safety Bulletins? I don't think that was a response to perceived faults of operation.. The Mandatory crankcase inspection SB was attributed to 'operation', though I note that Rotax changed the crankcase...the Mandatory replacement of gearboxes SB of '08 doesn't seem to me to be predicated on operation... The oil pump drive pin replacement Mandatory of '01 appears to be a manufacturer's problem, not one bought on by operational abuse...

 

If I am missing something here, please enlighten me.

 

If you want perfect safety in an engine, then go buy Rolls-Royce, at several $M a pop - oh wait, don't do that if you are running an Airbus 380...

 

 

hhey oscar im only new to flying and this site but am loving both, well mayb flying a bit more, havent looked into the number things yet so can u tell me what the diff is in 55 and 24 i only intend at this point to fly ra aus due to costs etc but certainly think the jab 230 is a good sized aircraft for touring.certainly would be a no brainer to install a camit motor as opposed to a rebuilt jab 1.thanks for your info was good reading and will be investigating further.

Jeff, there are plenty of people here better able to enlighten you about the subtleties, but there's a useful explanation of the rego class differences at: http://flysafe.raa.asn.au/regulations/regulations.html (if you wade down a bit, there's a 'summary table' that's pretty useful). VERY crudely speaking (and I'm sure that others will fill in the gaps I may have missed), in regard to your ideas: if it's 24-reg, you can only do what the manufacturer allows (though even that's not totally cut-and-dried, but unless Jabiru accept the CAMit version engine, it's going to be difficult, at least until the CAMit engine gets certification to the same level as the original engine installed by Jabiru, and even then it will probably need an engineer's certificate AND be a 'C'-model). A 55-reg aircraft (and it may be that there are no 2X series 55-reg. anyway, but the RAA register doesn't provide definitive information there) can be modified under an Engineering Order and still maintain its status as an aircraft available for training. 19-reg. is much more 'run what you brung' - within sensible limits - but has restrictions on its operation (you can't do your training in a 19-reg aircraft unless you have been the builder, for instance.)

 

I would LOVE to do exactly what you are saying: run a 2x series with a full fruit CAMit engine. There's no way my Doberman will fit in our ST1, even if I duct-tape him into a compact ball...

 

 

So how many Jab engines have had problems before 25 hours? How many Jab angines have had problems? how many Jab engines are problem free? Give us some facts and figures.As far as the military go how many hours do they put on a Rotax drone engine before they replace it? the figure is published.

The answer to your first question is, of course: too many. Even ONE is too many - but that needs to be qualified by what caused the failure: a basic design problem, faulty QA, or something that wasn't done properly? If we had authoritative figures by cause rather than mostly anecdotal evidence (which is not invalid but also isn't really qualitative), we could realistically sheet home blame.

 

The answer to the second can be fairly well assumed from the advertisements for used aircraft and comparing the engine to airframe hours. I spent a lot of time doing that over several years and there's no contest that a typical replacement/rebuild, mostly for 2200-engined Jabs., is done at around 300 - 350 hours.

 

The answer to the third question is: some. Interestingly, some commercial operators have numerous incidences of 1,000 hours-plus Jab engines, which suggests that careful operation and maintenance is a very large factor in the sort of life expectancy that can be achieved.

 

The question of Rotax engines used in military drones is a very, very interesting one. If you go to: http://www.google.com.au/url?sa=t&rct=j&q=&esrc=s&source=web&cd=6&ved=0CE0QFjAF&url=http://www.uadrones.net/military/research/acrobat/0302.pdf&ei=LyO6UtPdNISRigfNm4G4Cg&usg=AFQjCNHnaMmNjceBYJuTwoLdvDrXsdrCqQ&bvm=bv.58187178,d.dGI you'll find that for the RQ 1_B Predator (using originally 912s, now upgraded to 914s), the MTBF in operation over 5 years or so is - wait for it - 55.1 hours. Power/prop failures accounted for 53% of total failures; of that 53%, the engine was responsible for 'nearly 70%', or what I think means 37% of all failures.

 

I'm not sufficiently numerate to draw any conclusions from that but to me, if the average MTBF is 55.1 hours and 37% of the failures come from engine problems, a number of engines are giving trouble in fairly short times.. The Predator operational life is 'expected to be 2,000 hours.'

 

 

It's pointless to compare auto engines with aero engines. The average car is never flat out and your plane engine IS on every take off, the first one being from a cold start with minimum warm up. There's also plenty of auto car makers of good repute who have never made a good aero engine, and have tried. Aero engines have all parts shaved to the minimum size for lightness, making every part a critical design. Nev

Absolutely true. Possibly a bit of a comparison can be achieved by looking at the history of Subaru conversions (and I drive and am very enthusiastic about Subaru's). The EJ22 engine is by and large very well regarded and if looked after moderately well (oil changes on schedule, mostly) will typically run 300,000k or so of normal daily driving before needing a rebuild. The EJ25 a bit less, and even the old EA81 was generally considered pretty bulletproof (provided one purged the cooling system properly and didn't cook the heads). At let's say an average achieved speed of 80kph (for mostly country work), that's - if my calculator isn't playing tricks on me - about 3750 hours. I haven't seen any TBO achieved figures for the aero conversions but I'm willing to bet if they've been getting those sort of hours, you'd be hearing about it..

 

The problem is Jabiru has faults and Jabiru are very slow at addressing them, certification may be part of the problem. Rotec have produced liquid cooled heads, TBI, 45amp alternator and electronic ignition many private owners have improved reliabity by various modifications. Now Camit for whatever reason have shown a huge initiative to improve the engine and as original manufacturer are well qualified for the job. This is a huge leap forward and I would like to see the engine reliable and be able to be used and approved by Jabiru for factory built aircraft.

Precisely. CAMit are working up experience right now of reliability in real-life useage plus continuing to do research, analysis, design, manufacture and testing on additional elements they aren't yet ready to release. The results will start to come in in the not too distant future. Nobody is being asked to take it on trust that these changes are real improvements. If these developments offer better reliability than standard Jab. engines on average there are well over 1,000 Jabs out there that stand to benefit from being able to slot in a 'better' engine without going through a FWF change with all the attendant problems of engineering justification, performance testing for the upgrade of the POH, etc. etc. , that's a lot of aircraft that will keep on flying with minimum hangar time.

 

 

ThaThan you oscar for a very informative post, much appreciated but I come from military back ground where we just didn't have no where the problems jab seem to have. I will always have a soft spot for Jabiru as I passed my pilot certificate in one back in 1998. But I did feel like I was a student and test pilot at the same time

Hell, a military background is probably the most diametrically opposed to the civilian regulation regime for RAA-class aircraft that could be! The military don't give a flying fur-lined intercontinental sexual moment for arbitrary regulations - they specify what will do the job necessary! Type Certification doesn't exist as far as the military are concerned. Show me a military aircraft that cost less than $100k and I'll point out that it was a bloody CT-4 or a Jindivik.

 

Nobody gets let loose on military equipment without the proper training. Maintenance is carried out by specialists - pilots don't take spanners to their Blackhawks before they head up yonder. Nip into the local servo for a fill of whatever was in the bowser for your Eurocopter lately? Done the rocker settings on your F/A-18E/F within the last 25 hours?

 

You seriously can't expect something that has to weigh about twice that of a Harley, costs the purchase price of a schmicked-up Commodore, gets across country PTP faster than a turbo-Porsche and chews fuel at about the l/100k rate of a WRX also last like a Kenworth. Can I point out that 350 hours average life (to pick a figure that is not unexceptionable for a Jab. 2200) @ 90 knots average is about 550ks distance travelled? How many $85k cars can you name that will still be happily rolling along on first engine life if their lives were spent at 75% maximum power for those 550ks?

 

Yes, the Jab engine can be considerably improved. I've put my money where my mouth is on belief that that is what CAMit are doing. How much is it costing you to deny the possibility?

 

 

And a Merry Christmas to all, indeed! Yes, I was being cheeky - but the tendency of some posters to shoot from the lip does none of us any damn good in trying to get hold of engines that we can trust to fly behind.

 

I've had the opportunity of seeing the developments that CAMit are introducing first-hand and being able to sit down with Ian Bent in front of his computer and see his worked-up analysis of problems and solutions presented in FEA and CAD design packages; of having the rationale and the underlying analysis of changes explained. Ian has taken the time to take me through the development cycle of his changes starting with first-principle discussion of the function of components to the final design of changes to address issues. I've had the opportunity of people stopping CNC machines in mid-cycle to show me how the manufacture of parts in Jabiru engines progresses. I've watched the guys in the assembly shop put Jabiru engines together and had them tell me the little tips from experience of literally hundreds, probably thousands, of engine assemblies. Hell, I was able to use the tools - the torque wrenches, the sockets, the exquisitely developed special tools used for production assembly of these engines.

 

Just checking the tolerance of compression rings - not just the end-gap, but the production grinding of them, has a special tool to ensure they are seating on their full circumference. CAMit doesn't assemble a Jab. engine unless every damn compression ring is sealing properly - and they're all hand-checked! The new CAMit through-bolts have a better than 40% greater ultimate load strength than the Jabiru 7/16th through bolts and the new CAMit barrels eliminate the bending problem that over-stresses the through bolts under detonation anyway.

 

The engines we use in RAA-class (LSA for short, though that isn't a proper explanation) aircraft are built to optimise performance against weight. Every kg. of weight in the engine is a reduction of the useable load against the MTOW limits - which are completely arbitrary,when one comes down to analyse them. The only rationale for things like the MTOW limits happens to be the fact that there were a lot of 1,000-foot strips in the USA, so the FAA decided that a formula that allowed use of 1,000-foot strips was a decision point. From that, a minimum VSo was determined and some smart-arsed engineer decided that a particular MTOW should be imposed. A Westland Lysander could more than happily use 1,000-foot airstrips - but because some peanut equated airstrip length to MTOW instead of wing-loading, we are stuck with MTOW limits. If you read the article by Phil Ainsworth that I referenced above, you will see the decision process that Jabiru faced in producing its own engines- and extrapolate from that, the compromises that they had to make in the design of that engine.

 

I know from first-hand experience that the new CAMit (not Jabiru) through bolts are produced to a tolerance that means that the engine cases and the bolts themselves need to be at the same temperature to allow the bolts to be inserted. I know from the same experience why formed threads rather than cut-threads are mandated for certain components. I know why the pistons are placed in a certain direction vs. the gudgeon-pin offset with respect to the engine direction of rotation. I know that the new CAMit through-bolt nut base radius is matched to the barrel-flange base radius and doesn't require grinding. I know that the new CAMit through bolts are torqued to something like 40% of their yield stress at optimum torque for the case hold-down force required, rather than more like 95%. I know that the new CAMit rocker arms reduce the side-loads on the valve-stem by a great deal. I know why the new CAMit barrel-base thickness reduces the leverage load on the through bolts/studs even under detonation conditions by a handsome amount. I know why the new CAMit case-assembly technique is not critical on a five-minute start-to-torqued-up assembly time. I know why my oil pick-up won't have bits of silastic sticking in it when I come to re-build my new engine.

 

And more than anything else, I know now how various components in my Jab. engine interact in use. That is critical information in evaluation of how changes are going to affect the engine life and performance - and without that knowledge, the pontifications of self-important kibitzers as to how to 'fix' the issues with Jabiru engines are worth no more than flatulence in a jam-jar. If you're happy to base your choice of engine to turn your propellor on opinions worth no more than a T-shirt slogan saying 'Holdens rule - Fords suck' (or vice-vera) - then go right ahead. It's your money, not mine.

 

 

The whole test-cell thing used to be the way to go, but why would manufacturers do it this way nowadays? All they need to do is even just indicate they are thinking about building an engine and they will be told what they've done wrong, what they're going to do wrong, how to fix it, and why it'll never be half as good as a Rotax anyway, if they read some of the comments on this site.

 

 

Just by way of a little perspective on what is realistic in real life for a small aero-engine manufacturing company with reference to the Jab. engine development story, here's a shot from the official UL Power site of their engine test rig (or you can see if in action in the video on their site!)

 

http://www.ulpower.com/news/blog/wp-content/uploads/2013/01/Picture-1.jpg

 

I am in no way having a shot at UL Power here - I chose them by way of illustration because they are producing engines of highly-comparable specification to Jabiru, are in a relatively ab-initio phase as manufacturers, are using very comparable manufacturing techniques - and they have provided easily-accessible informative material. Indeed, it's worth reading this whole page on their testing regime: http://www.ulpower.com/news/blog/a-look-behind-the-scenes-of-ulpower-testing-the-ul520i

 

All in all, what Jabiru did by way of testing in their initial development phase is pretty comparable. Nowadays, every engine that leaves CAMit is test-run for 20 minutes on their in-house sophisticated dyno - they aren't just built and crated off the assembly-room floor. That's nothing to get too excited about, I'd imagine it's pretty much industry-standard practice; one would get 'excited' if it weren't the case, I suspect. I imagine that as their manufactured base gets larger, UL Power will move from using that trailer to a dyno as well!.

 

The point I am trying to make here, is that it's a pretty damn hard financial road for a small company to get a product as demanding as an aero-engine off the drawing board (or the CAD-machines, now) and out the door of the factory ready to be bolted up and flown.