Jabiru engines

[biggles]

Jabiru twin test flight .... Bob

 

 

 

[turboplanner]

http://www.aviationadvertiser.com.au/detail.php?id=4293 it sure is taking it's toll on values.

I had a look a couple of days ago; thinking back to around 2008/9, LSA550s were selling around $40,000 to $50,000, J160s were selling around $65,000 and the new J170 was selling at around $85,000.00

If you plug in 7 years of depreciation, they're not doing too bad.

 

There will be some being sold at quit now I need to may a debt values,and there has just been a FURIOUS fight on a stud sheep site between breeders who want to sell at top dollar regardless of the current financial situation, and those who need to urgently offload sheep, so general market conditions will be having an effect.

 

 

[rankamateur]

Can one of our retired aero engineer types tell me if this is a good idea, or does it impact on demonstrated stall recovery of an aircraft type? I have seen it done to balance heavier turbo installation and have wondered if it was OK.

That meant to say Spin recover, considering the added inertia in the added lead.

 

 

[jetjr]

Camit engine incorperates camit mods NOT Jabiru mods.

 

It is a significantly different engine to what Jabiru sell today

 

The weights shoulnt be much different but you do have a few heavier items like barrels and larger altenator

 

You can now get new light altenator if you like

 

Obviously entire new CAE engines arent effected by limitations and Ian has written word saying new cores are exempt too as they are significantly upgraded.

 

 

[Old Koreelah]

...the CAMIT is 10kg heavier than the Jab, which totally upsets the C/G and 6kg of lead now resides in the tail of my bird to compensate, the Camit alternator is wired totally differently, etc etc.

Given our weight limits Roger, that seems a wasteful thing to do. Presumably, the engine could not be mounted any further back. Can you relocate the battery and tool kit behind the cockpit? Perhaps you could make a compartment for the tie-downs near the tail.

 

 

[ROGER.G]

10 kg heavier Roger? Jabiru list their 3300 @ 83.5kg and Camit list their 3300 @ 82.4kg. Where is the extra weight in the Camit. Not doubting your figures, just asking.

My kit was delivered in 2000, so it is an early model solid lifter engine. At the time, I seem to recall Jab advertising the weight of the 3300 engine as 70kg, 'lighter than a Rotax'. This probably did not include the exhaust system, and the early engines may be lighter than the later hydraulic versions.

When I completed the build, the aircraft was professionally weighed, and the verdict at that stage was that is was nose heavy configured 2POB with no fuel (my tank is behind the seats, no wing tanks), and I was directed to instal 6kg of lead in the ventral fin. It was in this configuration that the C of A was issued.

 

A couple of years down the track I had a think about this additional dead weight in the tail, and decided to relocate the battery from the firewall to the back of the luggage compartment. This had the desired result, and I could dispense with the ballast.

 

I honestly don't know what the manufacturers specifications are for the later Jab engines, I do know that one of the advertised differences between Camit and Jab is that the CAMIT has heavier cylinders. The flywheel attachment of the Camit is also significantly different to the Jab (heavier) and I also assume that the 40 amp alternator is heavier. What I can confirm with absolute confidence is that with the old engine, the weight on the nose leg was approx 65kg. With the Camit installed, this had jumped to 83kg! This was not some sort of aberration or my eyes reading the scales wrong, it took noticeably more effort to lift the front of the aircraft to move it around.

 

As for the desirability (not) of adding ballast to the extremities of the aircraft, probably a good point. But this was how my aircraft was granted it's C of A in the first place, so we are back to square 1 in that regard. I am trying to think of a way to relocate the battery further rearward and maybe ditch some of the lead, but it's a bit difficult without interfering with the structure, and that is a no-no.

 

Anyhow, all this does not seem to have made any difference to the handling. I don't know about spins, they are prohibited!

 

 

[Jabiru7252]

Jabiru twin test flight .... Bob

 

Wow! I have been accused of 'thrashing' the joystick to death but this guy runs rings around me.

 

 

[jetjr]

Jamie is possibly the most experienced Jabiru pilot in AU.

 

If its rough conditions they need it

 

 

[scre80]

Wow! I have been accused of 'thrashing' the joystick to death but this guy runs rings around me.

that is exactly what I was thinking!!

 

 

[Oscar]

Well, the CAMit barrels are 275 grammes approx ( 276 on my kitchen scales..) heaver than the Jab standard ones, so there's 1650 grammes already. The alternator is quoted as 1.7 kgs heavier than standard, so there's now 3350 grammes added. The stronger flywheel might add maybe 250 grammes? The through bolts are considerably more meaty than standard Jab ones, but I doubt if that could amount to more than about 50 grammes per bolt, and the Jabiru locating dowels go, so maybe 40 grammes? Rocker gear would be line-ball for weight. I don't recall the earlier CAMit flange being different from Standard, later ones may well be enhanced.

 

I would have expected about 5 kgs all up heavier for a full-fruit CAMit engine, with a fair bit of that (alternator, flywheel) being fairly close to the c/g so compensating weight for that at the tail moment would be, (at a rough guess) maybe half of that?

 

Roger, did you add anything else - like replace the oil cooler? (the original Jab flat one was rubbish; a decent Aero Classics 7-row will add probably well north of 1KG and the lines a bit also.

 

Did you change props? Change to the s/s/ exhaust system from the original Jab?

 

Same as Gandalph, I am in NO WAY doubting your figures - getting an accurate handle on the conversion details is going to be important for lots of Jab. owners. In the (fairly likely, I suspect) event that there is a 'standard' conversion developed under MARAP, it is real experience such as yours that will contribute greatly to the development of the most effective 'scheme' for conversion. This is all valuable information!

 

 

[Ombre]

The Senators are making some pertinent enquiries into this CASA mess

 

and while their at it, maybe they should be making some enquiries

 

about the contentious ASIC card as well.

 

Cheers

 

 

[rankamateur]

I don't know about spins, they are prohibited!

Not being able to recover from a spin would be prohibitive!

 

 

[ROGER.G]

Well, the CAMit barrels are 275 grammes approx ( 276 on my kitchen scales..) heaver than the Jab standard ones, so there's 1650 grammes already. The alternator is quoted as 1.7 kgs heavier than standard, so there's now 3350 grammes added. The stronger flywheel might add maybe 250 grammes? The through bolts are considerably more meaty than standard Jab ones, but I doubt if that could amount to more than about 50 grammes per bolt, and the Jabiru locating dowels go, so maybe 40 grammes? Rocker gear would be line-ball for weight. I don't recall the earlier CAMit flange being different from Standard, later ones may well be enhanced.I would have expected about 5 kgs all up heavier for a full-fruit CAMit engine, with a fair bit of that (alternator, flywheel) being fairly close to the c/g so compensating weight for that at the tail moment would be, (at a rough guess) maybe half of that?

 

Roger, did you add anything else - like replace the oil cooler? (the original Jab flat one was rubbish; a decent Aero Classics 7-row will add probably well north of 1KG and the lines a bit also.

 

Did you change props? Change to the s/s/ exhaust system from the original Jab?

 

Same as Gandalph, I am in NO WAY doubting your figures - getting an accurate handle on the conversion details is going to be important for lots of Jab. owners. In the (fairly likely, I suspect) event that there is a 'standard' conversion developed under MARAP, it is real experience such as yours that will contribute greatly to the development of the most effective 'scheme' for conversion. This is all valuable information!

You are correct, I did replace the original automotive transmission cooler bit of rubbish and this was after the previous w & b. Also prop attachment upgrade (longer bolts, extra washers). The modified arrangements for cooling may have also added a few gm's. Additionally, I went to a fair bit of effort to ensure that the aircraft was level this time around using laser on the fuse join line, rather than a spirit level on the door sill as suggested by Jab, so it could be that the previous w & b calculations were flawed for that reason. Tilting the airfare , even a little, can make a difference.

The first model SP6, as I understand, was virtually a slightly stretched version of the earlier four cylinder airframe with the heavier 6 cylinder engine shoehorned in, hence the nose heavy verdict after the initial weighing. I suspect the later J versions may be a bit less critical in this area.

 

I suppose my point is that, just because two engines look the same and bolt up the same does not mean that a bit of diligence in these areas does not go astray.

 

 

[Oscar]

Roger - I will guarantee that the door frame bottom on any of the early narrow-fuselage (aka LSA55/derivatives) is a complete pile of , ahem, for level. Just try it for comparison side to side: and pick the one that you like!.

 

If your original W&B was done with the small wheels and you have changed to the larger ones since (as most people who fly out of anything other than tarmac strips have done), then the effect of the bigger diameter will add to the change for tilting. If you have changed to the later (heavy-duty) noseleg, that will also add a bit - and the bigger nosewheel + tyre would add a kg or more, I'd suspect.

 

The LSA55-airframe engine mount is the same - same part no. - for the 3300 and the 2200 engine, so the c/g of the 3300 engine moves forward by around 50% of the extra length. That's not the same effect on the W&B of 50% of the actual engine length difference, obviously, since the c/g of the engine will be aft of 50% of its length. The CAMit alternator and flywheel upgrade adds overall weight - but is closer to the aircraft c/g than the engine c/g, so the compensating tail ballast won't be at anything like 1:1. The move to using the Belleville washer pack for the prop retention would be sod-all in the scheme of things.

 

Can you think of ANYTHING that has been added - either since the original W&B was done, or within the context of the swap to the CAMit engine - forward of the firewall to your aircraft? This could be valuable advice to those who wish to follow your path.

 

Your point that: 'just because two engines look the same and bolt up the same does not mean that a bit of diligence in these areas does not go astray' is a really good one. Everybody should take note.

 

 

[jetjr]

Somethings going on if youve picked up 20kg nose weight

 

Camit flywheel is lighter I think, larger alt is off set by missing stator

 

Theres a new light weight altenator now too

 

Information i received was tht a w&b was optional as engine weights very similar

 

 

[Peter Anson]

One of the sad things about CASA's actions has been that many people have had their trust in their engines destroyed even though they have had no problems. I read one owner's post to a forum saying that he wished he could afford to replace his Jabiru engine with a more reliable Camit engine. He then went on to say that he had had absolutely no problems with his Jabiru engine, so presumably more reliable than 0 problems is negative problems.

 

At the time of the CASA action, I spent a bit of time going through all the accident and incident reports I could find, essentially the 2013 and 2014 reports on the RAA website, and eliminated all the reports that were obviously nothing to do with engine failures, such as running out of fuel. The things that impressed me were:

 

• The paucity of information and how many reports were incomplete
   
   
  
• There was no obvious increase in the number of failures from 2013 to 2014 so it was hard to see what CASA's justification of the increasing rate of failures was based on.
   
   
  
• There were several failures that could be attributed to broken through bolts or valve failures - these are obvious problems
   
   
  

 

 

The through-bolt failures puzzle me because with a rough calculation they would appear to be strong enough and they shouldn't be subject to fatigue loading unless they are not torqued up correctly. Apparently the problem didn't show up until the introduction of hydraulic lifters, but that shouldn't have any bearing on it.

 

I suspect the valve failures might be associated with high engine temperatures - my guess only. I think it is fairly common to only measure CHT on one cylinder, usually #4 on a 2200 or #6 on a 3300 because they are the rearmost cylinders but on my engine, the #6 is the coolest. #3 and #5 run hotter, so maybe pilots are unwittingly over-heating their engines.

 

Another consideration is that the majority of Jabiru engines end up in homebuilt aircraft, like my Sonex, which do have a higher failure rate than factory built aircraft, and over which Jabiru have little or no control. That isn't to say I think the engines are bullet-proof, they are very lightly built and that comes at a cost. All the same, it is very hard to find useful statistical evidence for CASA's action. They seem to just keep on repeating the same line without ever showing the evidence.

 

Peter Anson

 

Sonex 19-7898

 

Jab 3300 240 hours

 

 

[planedriver]

Sadly, Peter, a lot of what you say is true. However, many who do their own maintenance, are not as good as others at what they do, and the same goes for the manner in the way they operate them.

 

With diligent attention to detail in that regard, many, (admittedly not all) seem to give good service for the money paid.

 

We'd all like the best available, but as the old saying go's, one pays the money and makes their choice, though this doesn't please everyone..

 

 

[ROGER.G]

Roger - I will guarantee that the door frame bottom on any of the early narrow-fuselage (aka LSA55/derivatives) is a complete pile of , ahem, for level. Just try it for comparison side to side: and pick the one that you like!.If your original W&B was done with the small wheels and you have changed to the larger ones since (as most people who fly out of anything other than tarmac strips have done), then the effect of the bigger diameter will add to the change for tilting. If you have changed to the later (heavy-duty) noseleg, that will also add a bit - and the bigger nosewheel + tyre would add a kg or more, I'd suspect.

 

The LSA55-airframe engine mount is the same - same part no. - for the 3300 and the 2200 engine, so the c/g of the 3300 engine moves forward by around 50% of the extra length. That's not the same effect on the W&B of 50% of the actual engine length difference, obviously, since the c/g of the engine will be aft of 50% of its length. The CAMit alternator and flywheel upgrade adds overall weight - but is closer to the aircraft c/g than the engine c/g, so the compensating tail ballast won't be at anything like 1:1. The move to using the Belleville washer pack for the prop retention would be sod-all in the scheme of things.

 

Can you think of ANYTHING that has been added - either since the original W&B was done, or within the context of the swap to the CAMit engine - forward of the firewall to your aircraft? This could be valuable advice to those who wish to follow your path.

 

Your point that: 'just because two engines look the same and bolt up the same does not mean that a bit of diligence in these areas does not go astray' is a really good one. Everybody should take note.

Oscar, I have dug up the specs for my original engine.

For the Jab 3300, the 'Engine Curb Weight, complete with engine oil, exhaust and starter motor' is listed as 73kg.

 

For the Camit, the Ramp Weight, including exhaust, Carburettor, Starter Alternator and Ignition is listed as 82kg.

 

I can send you a copy of these if you like. These weights tie in quite well with my actual measurements of the aircraft.

 

You obviously know much more about the technical details of these engines than a mug like me, all I know is what is in front of me.

 

All I can suggest is that the later Jab engines must have gained a bit of fat over the early models with the changes to hydraulic, different barrels and whatever else.

 

 

[ROGER.G]

One of the sad things about CASA's actions has been that many people have had their trust in their engines destroyed even though they have had no problems. I read one owner's post to a forum saying that he wished he could afford to replace his Jabiru engine with a more reliable Camit engine. He then went on to say that he had had absolutely no problems with his Jabiru engine, so presumably more reliable than 0 problems is negative problems.At the time of the CASA action, I spent a bit of time going through all the accident and incident reports I could find, essentially the 2013 and 2014 reports on the RAA website, and eliminated all the reports that were obviously nothing to do with engine failures, such as running out of fuel. The things that impressed me were:

 

• The paucity of information and how many reports were incomplete
   
   
  
• There was no obvious increase in the number of failures from 2013 to 2014 so it was hard to see what CASA's justification of the increasing rate of failures was based on.
   
   
  
• There were several failures that could be attributed to broken through bolts or valve failures - these are obvious problems
   
   
  

 

 

The through-bolt failures puzzle me because with a rough calculation they would appear to be strong enough and they shouldn't be subject to fatigue loading unless they are not torqued up correctly. Apparently the problem didn't show up until the introduction of hydraulic lifters, but that shouldn't have any bearing on it.

 

I suspect the valve failures might be associated with high engine temperatures - my guess only. I think it is fairly common to only measure CHT on one cylinder, usually #4 on a 2200 or #6 on a 3300 because they are the rearmost cylinders but on my engine, the #6 is the coolest. #3 and #5 run hotter, so maybe pilots are unwittingly over-heating their engines.

 

Another consideration is that the majority of Jabiru engines end up in homebuilt aircraft, like my Sonex, which do have a higher failure rate than factory built aircraft, and over which Jabiru have little or no control. That isn't to say I think the engines are bullet-proof, they are very lightly built and that comes at a cost. All the same, it is very hard to find useful statistical evidence for CASA's action. They seem to just keep on repeating the same line without ever showing the evidence.

 

Peter Anson

 

Sonex 19-7898

 

Jab 3300 240 hours

You are on the money there Peter. After overcoming early cooling issues, my engine was performing quite well, but the CASA action (coupled with some first hand negative reports from other Jab users as well as the grapevine) frankly knocked my faith in the Jab engine, so I opted for the CAMIT to obtain a bit of peace of mind.

 

 

[ROGER.G]

Somethings going on if youve picked up 20kg nose weightCamit flywheel is lighter I think, larger alt is off set by missing stator

Theres a new light weight altenator now too

 

Information i received was tht a w&b was optional as engine weights very similar

See my reply to Oscar. The c/g of the engine is some way forward of the nose leg, so an extra 9 (or 10) kg engine weight will translate to approx 18kg extra on the nose wheel, which is what happened to my aircraft.

 

 

[Oscar]

Roger: thanks for that info, you don't need to send it to me ( my 'bitzer' part-CAMit engine is a 2200) but it's going to be a useful reference for everybody considering heading down that track. Does yours include the CAMit engine-oiler system and the TOCA? I'll weigh those later today...

 

It's axiomatic that 'weight creeps in' with changes. We've seen plenty of commentary regarding the possibility of changing over to a 912 in various threads here over quite a time, with most of that concentrating on the weight differential. Only one 'real-life' example of the rest of that conundrum has emerged - Ian Boag's conversion, which he estimated cost him around $40k. I believe that AAK is doing / developing a 'kit' but I know very little about that, though an initial report suggested the weight change was very little, so your comment that the Jab. has gained some weight over time sounds pretty much on the money to me.

 

There's a lot more to be considered than just weight in contemplating a change as radical as replacing a Jab. engine with a 912 and this is not the thread to go into that, but your experience is, to me, useful in comparing the weight question ( the 'buggerising around' question is a different one entirely!) so what you have reported will surely be of great interest. It will be ALSO be of great interest, I think, if the CAMit operating experience shows them to be competitive on reliability with the 912's - because I, for sure, would think that if the reliability of the CAMit is close to the 912, the relative purchase price, operating cost, and pretty much 'drop-in change' - though your comments re changing the cooling arrangement and the alternator wiring are noted - of the CAMit change-over would be pretty attractive!.

 

 

[ROGER.G]

Roger: thanks for that info, you don't need to send it to me ( my 'bitzer' part-CAMit engine is a 2200) but it's going to be a useful reference for everybody considering heading down that track. Does yours include the CAMit engine-oiler system and the TOCA? I'll weigh those later today... It's axiomatic that 'weight creeps in' with changes. We've seen plenty of commentary regarding the possibility of changing over to a 912 in various threads here over quite a time, with most of that concentrating on the weight differential. Only one 'real-life' example of the rest of that conundrum has emerged - Ian Boag's conversion, which he estimated cost him around $40k. I believe that AAK is doing / developing a 'kit' but I know very little about that, though an initial report suggested the weight change was very little, so your comment that the Jab. has gained some weight over time sounds pretty much on the money to me.

 

There's a lot more to be considered than just weight in contemplating a change as radical as replacing a Jab. engine with a 912 and this is not the thread to go into that, but your experience is, to me, useful in comparing the weight question ( the 'buggerising around' question is a different one entirely!) so what you have reported will surely be of great interest. It will be ALSO be of great interest, I think, if the CAMit operating experience shows them to be competitive on reliability with the 912's - because I, for sure, would think that if the reliability of the CAMit is close to the 912, the relative purchase price, operating cost, and pretty much 'drop-in change' - though your comments re changing the cooling arrangement and the alternator wiring are noted - of the CAMit change-over would be pretty attractive!.

Another factor Oscar, is the relationship between purchaser and manufacturer. I have found my dealing with Ian Bent and his willingness to help to be totally positive. My superficial view of the CAMIT engine (mine was an engine core, so I had to do a bit of work to transfer components) was that a serious attempt has been made to rectify the reported Jabiru issues.

By the way, I am not on any sort of commission from CAMIT!

 

 

[Geoff13]

Oscar, I have dug up the specs for my original engine.For the Jab 3300, the 'Engine Curb Weight, complete with engine oil, exhaust and starter motor' is listed as 73kg.

For the Camit, the Ramp Weight, including exhaust, Carburettor, Starter Alternator and Ignition is listed as 82kg.

 

I can send you a copy of these if you like. These weights tie in quite well with my actual measurements of the aircraft.

 

You obviously know much more about the technical details of these engines than a mug like me, all I know is what is in front of me.

 

All I can suggest is that the later Jab engines must have gained a bit of fat over the early models with the changes to hydraulic, different barrels and whatever else.

That actually explains quite a bit and confirms my thoughts on the differences that I found when I converted my Jabiru 2200 over to a 912. Using the manufacturers data for both engines I calculated a weight increase of approx 10 kgs. In fact the actual increases was 16 kgs which led me to believe that the original earlier versions of the J2200 (which mine was), where in fact lighter than the current updated versions.

 

 

[Bruce Tuncks]

I have had a LiFePO4 starting battery for over a year now now and it weighs about 1kg. Taking about 5kg off the nose wheel is great.

 

The battery is only used for starting the engine and is disconnected from the alternator well before takeoff.

 

 

[Bruce Tuncks]

Oscar, I have always done the spirit level on the door thing.. what do you recommend instead? Is the fuselage join-line the horizontal reference we should be using?