CASA - Draft Proposal for Jabiru Aircraft

[Geoff13]

No!! Nope!!! Nu Uh!!! Never!!! Cant be done!!!!the 160C is an anomaly in the Jabiru line up and has a Type certificate, which means that a bunch of engineering approaches, completely divorced from the manufacturer, that are not available to LSA could be used to transplant the engines in the type certified 160.

 

Those engineering approaches are not available to LSA aircraft and that's why Dafydd and other have been pointing out time and time again that LSA SUCKS!!!! If you want an LSA to be modified, and still want the benefits of LSA such as hire and reward, then only the OEM can approve the changes if they choose not to, then you are sh!t out of luck.....

 

So....for the 20th time in this particular thread, and probably 200th in the site, and hopefully the very last time it is ever ASKED!

 

NO YOU CANT!

 

Andy

 

P.S Geoff we went over this a week or so ago, you asked the question and I said you could always go E24 and you said...cant do that I want to put it on line..... What you have asked above is the same question again.

Okay thanks Andy I appreciate your help, but I don't recall asking this question before or reading it in this thread relating to the J230. I will admit to sometimes when I come on here after a couple of days and see 8 to 10 pages in one thread I do not read all posts word for word but tend to just scan through. And in fact some posters explanations are often so technical or so belittling to other posters that I will admit to skipping some posts entirely. I was well aware that it can't be done with an LSA but I am not and was not aware of the special arrangement relating to the J160C. I thought that as when the J160C went LSA, they changed it to a J160D, that it was possible that the same may have been applicable to the J230.

 

P.S Andy. I am aware that you said I could go E24 in the case we discussed and I have not changed my opinion on that. This question was neither about nor for me, in fact I have said that I haven't really enjoyed flying the Jabs as much as the other few aircraft that I have been in and as such am not interested in buying a Jab, so I was not asking for my own benefit in this case. I asked the question to start a thought process that with all the talk of doom and gloom and FTF's going broke, in at least one case "J160C" there is a fix available. Admittedly not a cheap fix but it is possible and it would also help a lot of students who have invested a lot of time and money learning in Jabs. Now not knowing what every aircraft in the fleet is classed as may be a crime in some counties and may deserve your response which I actually think it was OTT and inappropriate. It may pay you to remember that not everyone here has read every post over the last 10 years or so nor should they have. And you have no right to try and make someone feel as though they should never ask a question for fear that it may have been asked before.

 

Now I am sure someone will run a spell/grammar check over this for me as seems to be the process around here when someone says something that they don't like so I shall save my own time and not bother running my own.

 

Cheers Geoff13

 

 

[dazza 38]

T

 

Thanks Bruce for your explanation, I always thought Tecnams had a fairly good reputation as far as safety goes.Nothings bullet proof, we all know the risks when we fly.

 

Hope all this issue with the Jabs get sorted out for you guys , They seem to be an affordable well constructed aircraft with a few engine problems ( no experience just what I read on this forum ) and it would be bad for all of us in RAA to see them grounded or put under severe restrictions, we all just want to fly safely,

 

cheers Butch

There is nothing structurally wrong with Tecnams. The golf that broke up (I fly a teccy Golf) , broke up because the pilot ripped the wings off it by over stressing the aircraft. Same thing would have happened most light aircraft.

 

 

[ave8rr]

Having followed the for and against re CASA's "draft" order in relation to Jab engines, it might be worth reading the article and watching the inflight video that eventually saw a Kununurra Tourist operator grounded.

 

http://www.theage.com.au/victoria/the-law-of-the-bungles-grounds-unruly-alligator-20120608-201bm.html

 

It was also safety concerns that has seen Tiger airways, Av8 in Darwin and a Cairns charter operator all recently grounded and except for Tiger eventually wound up. In the case of Alligator the owner was the chief engineer. They had at least three emergency landings due IO540 fuel pump issues at an aerodrome I was managing.

 

I have owned both a J200 and a J160 over the years and both aircraft had "top overhauls" at between 100-150 hours time from new costing thousands. The airframes are great in my opinion.

 

 

[Bruce Tuncks]

I'm sure there was nothing wrong with the Tecnam and I'm sure you are right Dazza. BUT metal aircraft are built closer to the edge because the edge is better defined with metal. I personally would fly in a Tecnam. But I still know the Jabiru is tougher when an undercarriage leg fails cos I've seen them both.

 

 

[Guest Ornis]

Yeah, it's fine to replace a couple of valves at 100 hours. No problem.

 

 

[jetjr]

Seen a tecknam with a one patch on wing and having flap repaired for a crack

 

anyway i dont like them so ill start accumulating anecdotal information and lobby CASA to investigate these well known structural problems.

 

 

[motzartmerv]

Seen a tecknam with a one patch on wing and having flap repaired for a crackanyway i dont like them so ill start accumulating anecdotal information and lobby CASA to investigate these well known structural problems.

Yep. When you get 40 reported cases in one year, come and chat..

 

 

[kaz3g]

http://www.theage.com.au/victoria/t...harged-with-manslaughter-20140903-10brau.html

I'm not sure what point you are making, Turbs.

 

Kaz

 

Edit: I just saw others have asked the same question. The charge would appear to be that she negligently operated a commercial vessel in circumstances where she knew or ought to have known that it was dangerous to another. But it's probably much safer to leave it at that until the matter is decided...kaz

 

 

[alf jessup]

Seen a tecknam with a one patch on wing and having flap repaired for a crackanyway i dont like them so ill start accumulating anecdotal information and lobby CASA to investigate these well known structural problems.

Fill ya boots JetR.

 

We've all seen a lot of Jabaroos have engine problems, I don't like the engine but love the airframe

 

 

[Bruce Tuncks]

Question: How can the through-bolts be failing if they are not stressed above the fatigue limit? Surely the cylinder pressures can be measured? I can imagine a sensor hole, a lot smaller than a spark-plug hole, being put into a test engine and connected to a data-logger.

 

Gosh I'll volunteer my engine if CASA can't afford one after all their executive salaries. Dafydd, you did once say that instrumentation was the hardest thing, but is it so hard?

 

Wow if there are no excessive pressures and the bolts then fail then I will apply for a refund of the

 

fees I paid doing my masters in mechanical engineering. I will sign up for astrology and stuff.

 

 

[dazza 38]

Seen a tecknam with a one patch on wing and having flap repaired for a crackanyway i dont like them so ill start accumulating anecdotal information and lobby CASA to investigate these well known structural problems.

Some Tecnams have a low VFE, the Golf is a low 60 knots and it could be better. But at least it is reliable.

 

 

[Guest Andys@coffs]

Okay thanks Andy I appreciate your help, but I don't recall asking this question before or reading it in this thread relating to the J230. I will admit to sometimes when I come on here after a couple of days and see 8 to 10 pages in one thread I do not read all posts word for word but tend to just scan through. And in fact some posters explanations are often so technical or so belittling to other posters that I will admit to skipping some posts entirely. I was well aware that it can't be done with an LSA but I am not and was not aware of the special arrangement relating to the J160C. I thought that as when the J160C went LSA, they changed it to a J160D, that it was possible that the same may have been applicable to the J230.P.S Andy. I am aware that you said I could go E24 in the case we discussed and I have not changed my opinion on that. This question was neither about nor for me, in fact I have said that I haven't really enjoyed flying the Jabs as much as the other few aircraft that I have been in and as such am not interested in buying a Jab, so I was not asking for my own benefit in this case. I asked the question to start a thought process that with all the talk of doom and gloom and FTF's going broke, in at least one case "J160C" there is a fix available. Admittedly not a cheap fix but it is possible and it would also help a lot of students who have invested a lot of time and money learning in Jabs. Now not knowing what every aircraft in the fleet is classed as may be a crime in some counties and may deserve your response which I actually think it was OTT and inappropriate. It may pay you to remember that not everyone here has read every post over the last 10 years or so nor should they have. And you have no right to try and make someone feel as though they should never ask a question for fear that it may have been asked before.

 

Now I am sure someone will run a spell/grammar check over this for me as seems to be the process around here when someone says something that they don't like so I shall save my own time and not bother running my own.

 

Cheers Geoff13

Understanding what every aircraft is, is simply not necessary to be understood because for existing RAAus registered aircraft the registration number will give it all away. Page 57 of the new ops manual has a table of registration prefixes and what they mean......Tables don't work that easily in this forum software without understanding the coding required (which I knew but have forgotten) and as such it may not reproduce very well, but here goes:-

 

10 - Amateur built (CAO 95.10)

 

17 - Experimental LSA (CAO 95.55 and 95.32)

 

18 - Amateur built - W/S and PPC (CAO 95.32)

 

19 - Amateur built (CAO 95.55)

 

23 - LSA - Factory built (CAO 95.55)

 

 

 

24 - Factory built - Certified (CAO 95.55)

 

 

 

E(xx)- Experimental LSA (e.g. E24- or E32-) (CAO 95.55 and 95.32)

 

25 - Superseded factory built (CAO 95.25 - Factory built)

 

26 - GA - Type Certified (CAO 95.55)

 

28 - Superseded (CAO 101.28 - Amateur built)

 

32 - Factory built - Certified (CAO 95.32 - W/S and PPC)

 

55 - Factory built (CAO 101.55)

 

 

The Redish codes above (excluding the E(xx) ) are primary LSA and as such cant be modified without OEM approval unless you are prepared to have it transition to E(xx) the 160C we were discussing is likely to be as per the green above, or maybe 26.......cant say as I know exactly cause I've never looked for one myself

 

 

 

Sorry if it came across as abrupt, but you may not have thought the question was the same but it really was...

 

 

 

Andy

 

 

[bexrbetter]

Question: How can the through-bolts be failing if they are not stressed above the fatigue limit? Surely the cylinder pressures can be measured?

Vibration at insidious levels. Plenty of cylinders with double the pumping and combustion pressures and making ridiculous high BMEP levels relative to a Jab that are held on with less.

 

It's a 550cc cylinder with 8:1 compression making a measly 20 hp for goodness sakes, it ain't cylinder pressures knocking them off.

 

 

[Geoff13]

Thanks Andy makes a bit more sense. I haven't read everything yet and I am working my way through the ops manual but I feel it will take many more readings to absorb it all. There is much to learn and most of my reading lately has been poh's on different aircraft.

 

The J160C that has the Rotax that I am aware of is a 24 reg and is online so I am now actually even more confused.

 

Cheers Geoff13

 

 

[Guest Andys@coffs]

Thanks Andy makes a bit more sense. I haven't read everything yet and I am working my way through the ops manual but I feel it will take many more readings to absorb it all. There is much to learn and most of my reading lately has been poh's on different aircraft.The J160C that has the Rotax that I am aware of is a 24 reg and is online so I am now actually even more confused.

 

Cheers Geoff13

Righto...I'll drop an email to Darren Barnfield and see if I can get to the bottom of it then

Andy

 

 

[jetjr]

Fill ya boots JetR.We've all seen a lot of Jabaroos have engine problems, I don't like the engine but love the airframe

Thats my point Alf, ive seen more Tecnam with strutural repairs than Jabiru with engine problems

 

Only one of the four at my airfield has had problems and it has done well over 2000 hrs, crashed a few times, by a long line of students

 

Even it was still runnng when 1500 hr engine removed for repairs

 

Not everyone has seen the problems, with a few experiences like Merv's and thats a lot of the problems

 

Im sure there are way more than 40 cracked up alloy planes, would mostly be unreported.

 

Anyone seeing the irony yet

 

 

[Downunder]

You have nothing to apologise for Andy.......... some people just need to read more and post less........

 

 

[Bruce Tuncks]

Bex, I really like what you are doing in China and I like your posts. But I had a vibration test done and the level was not high. It was one of those tests where you put a reflector on the prop and bolt a vibration sensor to the block, and it cost me $150. I had tried to get up a syndicate to buy the tester, but I failed to get any other contributors.

 

If it's not the cylinder pressures, what do you suggest should be done to measure what might be happening? I still think that if there is something real then it can be measured.

 

 

[kaz3g]

Thanks, I realised attempting to provide a subtle hint would be over your head.

This is like cryptic cross words...

 

Kaz

 

 

[Guest Maj Millard]

I'm sure there was nothing wrong with the Tecnam and I'm sure you are right Dazza. BUT metal aircraft are built closer to the edge because the edge is better defined with metal. I personally would fly in a Tecnam. But I still know the Jabiru is tougher when an undercarriage leg fails cos I've seen them both.

There's no way you will repair a composite airframe as easy or as efficiently as a metal airframe. Additionally you will always be adding weight when repairing composites. At least with metal you'll see the damage clearly, with composite you may not see it at all until things break. . Maj......FAA/ICAO Level 2 Advanced Composite- structures Certificate. 1996.

 

 

[cooperplace]

It's a 550cc cylinder with 8:1 compression making a measly 20 hp for goodness sakes, it ain't cylinder pressures knocking them off.

that's exactly what I thought when I first saw the jab design: not a lot of power, not a lot of compression. Shouldn't be much of a detonation problem, and twin plug heads to boot! This should further reduce the chance of detonation, if my understanding of the phenomenon is correct.

 

 

[bexrbetter]

But I had a vibration test done and the level was not high.

People compare the Lyc, Conti, Rotax etc but the fact is they are all short, stiff, 3 main bearing cranks, Jab has a longer 5 main bearing crank without counterweights, a Subaru with 5 mains has counterweights, there's 100% no doubt it twists/flexes but if that's a cause of the problem, i.e. the resulting TVs, I don't know. If I was at CAMit I would be trying a fully counterweighted crank or at least a semi counterweighted one for results. For the purpose of testing, it's as easy as welding on the counterweights.

 

Here's a Jab, semi-counterweighted Subaru and fully counterweighted Subaru cranks for comparison ..

 

 

As for TVs, just because you can't feel them doesn't mean they aren't there. The following isn't my writing, nor my area, but I do know someone far better equipped and I will contact him, it's quite a science to itself apparently ... Please take note of the last paragraph (tongue in cheek).

 

Torsional Vibrations:

 

Torsional vibrations are much harder to identify because they are often not felt.

 

Torsional vibrations exist in all rotating equipment (electric motor, reciprocating engine) throughout the

 

entire operating range. However, at certain speed/load (can be multiple locations) conditions they are

 

magnified. When a component’s natural resonance becomes excited by the frequency source, the

 

component is subject to extremely high movements. It is these extreme movements that generate forces

 

equal to multiple times the expected force. An example is the tuning fork breaking the glass. The damage

 

from a torsional vibration is typically unexpected and unexplainable by the serviceman.

 

Torsional analyses can predict the speeds at which a system may become resonant, thus allowing design

 

engineers to retune the system. This tuning is accomplished with various methods to include torsional

 

couplings. The calculations and instrumentation is typically performed by the equipment manufacture,

 

system packager, or torsional coupling manufacture. The individual components’ mass elastic data is

 

required as well as the operating speeds and any special conditions; shock loads, load reversals, desired life,

 

etc. On fuel powered reciprocating engines such things as fuel pressure, firing angles, cylinder mis-firing,

 

light rotating inertia, front viscous damper, light inertia driven loads, and propeller excitation also

 

contribute to the torque excitation. Once a base line vibration analysis is established, it becomes an

 

invaluable tool for identifying component wear and preventing costly failures & downtime.

 

A relatively unknown result of torsional vibrations is full torque reversal in which the applied torque

 

actually passes back and forth through zero. If a gear set is subject to this, a severe rattle can occur as the

 

gear teeth load and unload. The noise generated by this action can be very loud. Keep in mind that the

 

gearing itself may not be causing the noise as it is not defective but operating at a natural resonance. This is

 

why a seemingly proper sized shaft/gear/spline/bearing will wear very quickly. This applies to gear

 

reducers, hydraulic pumps & motors, hydraulic & mechanical transmissions, etc. The coulomb damping is

 

the relative movement between connecting surfaces. This is what the torsional coupling is designed to

 

control and maintain throughout the entire operating range and for the entire operating life.

 

Coupling selection for a power transmission system involves analysis of its dynamic torque capacity, either

 

by a TVA calculation or direct field instrumentation. Dynamic torque and torsional critical speeds must be

 

taken into account. Because torsional stiffness can be more easily adjusted at the coupling, the coupling is

 

often the component that ensures torsional compatibility for the entire system. Such systems then operate at

 

speeds that do not induce resonance, or they have enough isolation capacity at the critical speeds to control vibratory response. Systems that are dynamically compatible need low service factors, tend to be trouble-free free, and have long service life.

 

If you suspect torsional or linear vibrations exist in your equipment contact your equipment OEM,

 

packager, component OEM or coupling manufacture to discuss the problem and possible diagnoses.

 

 

[facthunter]

Bex...You are on the ball .Way over the head of most people unfortunately, as they don't have the training in basic physics nor do they perceive the relevance of the points you make. You don't "feel" torsional vibrations nor have any appreciation of the magnitude of them, until something breaks. Nev.

 

 

[dmech]

Vibration at insidious levels. Plenty of cylinders with double the pumping and combustion pressures and making ridiculous high BMEP levels relative to a Jab that are held on with less.It's a 550cc cylinder with 8:1 compression making a measly 20 hp for goodness sakes, it ain't cylinder pressures knocking them off.

hear hear dead right there bex

 

 

[dmech]

Vibration at insidious levels. Plenty of cylinders with double the pumping and combustion pressures and making ridiculous high BMEP levels relative to a Jab that are held on with less.It's a 550cc cylinder with 8:1 compression making a measly 20 hp for goodness sakes, it ain't cylinder pressures knocking them off.

but then second thought's it is actually abnormal cyl pressure that's causing ,as we have found and mostly eliminated in more than a dozen jabs, no broken bolts in 2 yrs so far 800hrs on one engine fts 160