Two more Jabirus down
I wonder whether those auto umbrella thingy's that pop out of the top of these toy planes should be more widely used.
I imagine you have a choice with those, you either pop it out if there's no suitable Ldg field within an assumed gliding distance or you go for a conventional crash Ldg (as the press would say). Cost no doubt is the deciding factor, not safety.
If someone could come up with an engine design along the lines of the old tried & proven Lyc's & Conty's which are almost bullet proof for these toy planes then they would be worshiped
Wmk2
I imagine you have a choice with those, you either pop it out if there's no suitable Ldg field within an assumed gliding distance or you go for a conventional crash Ldg (as the press would say). Cost no doubt is the deciding factor, not safety.
If someone could come up with an engine design along the lines of the old tried & proven Lyc's & Conty's which are almost bullet proof for these toy planes then they would be worshiped
Wmk2
Tankengine,
Precisely, but the "certified" stalling speed is CAS, not IAS, I wonder what the the static error correction is like at those low speeds.
I well remember older C-172, the IAS stalling speed was almost "off the clock", but corrected for static error was "as per the book".
Tootle pip!!
Precisely, but the "certified" stalling speed is CAS, not IAS, I wonder what the the static error correction is like at those low speeds.
I well remember older C-172, the IAS stalling speed was almost "off the clock", but corrected for static error was "as per the book".
Tootle pip!!
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Wally, I know you're a sceptic and I'm no evangelist, but I give 'quiet thanks' for my Rotax 912 S2. After years of flying the Lycs and Continentals, I admit that it took me a while to believe that the little donk was a good thing. I've seen the religious debate in other threads and have nothing much to add, except perhaps that the Rotax has done well when compared in reliability and maintenance cost terms with my other engines. My personal philosophy is to take the operation and maintenance seriously and, even if I had a choice, I'd never have my engine maintained by other than a LAME - and one I trusted. If anything, I'm even pickier with the 912 maintainers. A less agricultural touch is definitely the go!
I hate to rely on anecdotes (for the reasons mentioned in my previous advocacy of maintaining a proper RAA database) but the best information I could get when looking at alternatives is that the Rotax does do better than the smaller Jab engine in reliability terms.
I hate to rely on anecdotes (for the reasons mentioned in my previous advocacy of maintaining a proper RAA database) but the best information I could get when looking at alternatives is that the Rotax does do better than the smaller Jab engine in reliability terms.
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Lack of data is a huge problem. In theory the Jab should be more reliable simply because it has less components which could fail. It has no radiator and associated plumbing, no gearbox, no injectors , no injector pump and has a very simple ignition system. There's not much left to fail.
Is it possible it's perceived high failure rate is simply because there are a lot of them around. A lot of Holdens crash but there a lot of Holdens.
Internal combustion engines have been around for well over 100 years. It shouldn't be too difficult too pinpoint Jabs problem area if indeed there is one.
Human nature presents another problem. A mistake be it in installation, maintenance, engine operation or in flying skills is always the engines fault if nobody else saw it happen.
Could human error be why so many incidents go unreported?
Is it possible it's perceived high failure rate is simply because there are a lot of them around. A lot of Holdens crash but there a lot of Holdens.Internal combustion engines have been around for well over 100 years. It shouldn't be too difficult too pinpoint Jabs problem area if indeed there is one.
Human nature presents another problem. A mistake be it in installation, maintenance, engine operation or in flying skills is always the engines fault if nobody else saw it happen.
Could human error be why so many incidents go unreported?
I had an engine failure in a J160 in about 1994. The studs holding one of the cylinders onto the crankcase clean pulled out of the crankcase. Luckily for me, like the two young men in the video, I had a happy outcome. It would be interesting to know if the studs pulled out of the crankcase like they did for me.
Needless to say you would have to drug me to get me into one now.
Needless to say you would have to drug me to get me into one now.
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Rutan.
"Is it possible it's perceived high failure rate is simply because there are a lot of them around. A lot of Holdens crash but there a lot of Holdens.
Internal combustion engines have been around for well over 100 years. It shouldn't be too difficult too pinpoint Jabs problem area if indeed there is one".
I see where you are coming from Rutan, but in my experience, the failure rate
Is definitely not perceived.
And yes, light aircraft Engines (lycoming,continental) have been around a long time, time enough to put all of the lessons learned in to their Engines, long ago.
Why reinvent the wheel. I'm not saying you should not attempt to build your own engine to suit your own needs, but surely you would build on lessons past.
I remember when Rotax engines became more common, I didn't think too much of them at the time, but they have proven themselves to be an extremely reliable, well Engineered little engine.
"Is it possible it's perceived high failure rate is simply because there are a lot of them around. A lot of Holdens crash but there a lot of Holdens.
Internal combustion engines have been around for well over 100 years. It shouldn't be too difficult too pinpoint Jabs problem area if indeed there is one".
I see where you are coming from Rutan, but in my experience, the failure rate
Is definitely not perceived.
And yes, light aircraft Engines (lycoming,continental) have been around a long time, time enough to put all of the lessons learned in to their Engines, long ago.
Why reinvent the wheel. I'm not saying you should not attempt to build your own engine to suit your own needs, but surely you would build on lessons past.
I remember when Rotax engines became more common, I didn't think too much of them at the time, but they have proven themselves to be an extremely reliable, well Engineered little engine.
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Jabba,
Some interesting data. 7571 pruners have taken an interest in Jabs problems.Only 372 have even looked at your engine management course invitation. Does that mean they worry that there is a problem but aren't interested in possibly finding a solution? Or does it mean they have complete faith in Saint Instructor who was trained by Jurassic Instructor?
RA
Some interesting data. 7571 pruners have taken an interest in Jabs problems.Only 372 have even looked at your engine management course invitation. Does that mean they worry that there is a problem but aren't interested in possibly finding a solution? Or does it mean they have complete faith in Saint Instructor who was trained by Jurassic Instructor?
RA
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Rutan
Smart, bright and quick witted as well as very adventurous are qualities of both Mr Rutan's.
You however posses these qualities it seems, but have too much time on your hands to notice!
Smart, bright and quick witted as well as very adventurous are qualities of both Mr Rutan's.
You however posses these qualities it seems, but have too much time on your hands to notice!
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Perspective,
I don't think there is anything wrong with trying to improve the wheel. eg Jabiru's excellent power to weight ratio.You just have to be careful and move quickly if or when a problem emerges.
Some
made by Continental and Lycoming have cost owners a disasterous amount of money and even cost some lives before those companies were forced kicking and screaming to rectify the problems. Lycoming's crankshafts and Continental's belled out cylinders come to mind.
RA
Why reinvent the wheel. I'm not saying you should not attempt to build your own engine to suit your own needs, but surely you would build on lessons past.
Some
improvements
RA
Man have they made a fairly ordinary looking toy plane even uglier with that twin thingy, it looks like a strange fish with warts!
A twin Jabby, twice the problems
'Tecy' I gather the Rotax is pretty much well known these days having been around a day or two & there would be few if any surprises out there for the owners of same.
I read with interest the Bugatti Veyron has a W16 donk returning 3MPG at full tilt (250MPH+ on 1001 HP) & the engineering design that has gone into that machine (fascinating YouTube on it all) actually has produced a stunning 3000HP (2000HP gone due heat) so why not have some higher level of design done for Aero engines, after all a Bugatti donk fails ya pull over call yr lawyer & sue the crap out of Bugatti, yr garden variety Jabba junk donk fails yr family calls the lawyer!
There's 3 basics things needed for typical low comp 'infernal' combustion engine to work, Air (that's a certainty providing ya don't clog the inlet up!) fuel & a source of ignition but you would think after a 100+yrs of stuffing around there's still problems with the basic man made design, time to start all over again I think & lets all vote Jabba Dabba Doo as the head of the new technology, over to you Jabbs & try not to waste much energy on heat will ya buddy!
Wmk2
A twin Jabby, twice the problems
'Tecy' I gather the Rotax is pretty much well known these days having been around a day or two & there would be few if any surprises out there for the owners of same.
I read with interest the Bugatti Veyron has a W16 donk returning 3MPG at full tilt (250MPH+ on 1001 HP) & the engineering design that has gone into that machine (fascinating YouTube on it all) actually has produced a stunning 3000HP (2000HP gone due heat) so why not have some higher level of design done for Aero engines, after all a Bugatti donk fails ya pull over call yr lawyer & sue the crap out of Bugatti, yr garden variety Jabba junk donk fails yr family calls the lawyer!
There's 3 basics things needed for typical low comp 'infernal' combustion engine to work, Air (that's a certainty providing ya don't clog the inlet up!) fuel & a source of ignition but you would think after a 100+yrs of stuffing around there's still problems with the basic man made design, time to start all over again I think & lets all vote Jabba Dabba Doo as the head of the new technology, over to you Jabbs & try not to waste much energy on heat will ya buddy!
Wmk2
Last edited by Wally Mk2; 6th Sep 2013 at 21:10.
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Rutan,
They have a way to go before they even
Get up to the wheel, let alone improve on it!
I can easily give you a half dozen reasons why.
And We have tried to "assist" with product improvement,
The "wheel" turns slowly
They have a way to go before they even
Get up to the wheel, let alone improve on it!
I can easily give you a half dozen reasons why.
And We have tried to "assist" with product improvement,
The "wheel" turns slowly
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And We have tried to "assist" with product improvement
You've only got to talk to the manufacturer to realize that he knows far more about engines than 99% of the operators will ever know, but yet operators of these engines that have rebuilt their old motorbike or jet ski engine usually believe that they know more than the manufacturer. Many of the "improvements" suggested by operators of these engines are a joke and if other operators followed their advice they would end up in a box (and I am not referring to the engine being in a box!)
Last edited by VH-XXX; 6th Sep 2013 at 21:50.
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I attended a forum at Oshkosh on Jab cooling presented by Robert Gutterage. Maybe most of Jabs problems are insufficient cooling going undetected due to incorrect CHT information being presented to the pilot. Certainly Robert presented a very well researched forum backed up by hard data.Note :- He had data--- Not a bunch of ' I thinks ' He showed slides of what he did to solve the problem in his aircraft as well as before data.
Apologies to Tim Juhl for pinching the following from a forum on Jabs.
(Remember-stealing articles from one writer is plagiarism----stealing from many is research.)
It's worth looking at the last web site outlining Robert's qualifications.He's the right man for the job.
For all those who want to junk the Jab engine for as yet no clearly defined problems it would be good if you reflected on the Wright R3350 turbo compound engine used in the B29 and in the Super Constellation. When those engines were first used their TBO was typically 200 to 600 hours.Ouch
After they learned to operate them properly (essentially by running them lean of peak) they were often getting TBOs of 3,600 hours
all with 1940s technology. Lycoming and Continental should hang their heads in shame.
RA
Apologies to Tim Juhl for pinching the following from a forum on Jabs.
(Remember-stealing articles from one writer is plagiarism----stealing from many is research.)
I attended a forum at Oshkosh where a fellow discussed his research on cooling a Jabiru 3300. He had compared the spark plug washer type CHT sensors to ones directly in the head and showed that they pretty consistently indicated CHT's about 70° cooler than actual temperatures! If this is the case, Jab operators could be cooking their engines while thinking that their CHT's were within safe limits. He ended up designing a cooling baffling system that is nothing like what comes from the factory and claimed that was the only way he was able to get the CHT's under control.
I wonder what the rest of you Jabiru 3300 operators have to say about this? I'm not flying mine yet but will be getting ready to hang it soon.
For a summary on the fellow who made the presentation check out EAA AirVenture Oshkosh - The World's Greatest Aviation Celebration
EAA AirVenture Oshkosh - The World's Greatest Aviation Celebration
I wonder what the rest of you Jabiru 3300 operators have to say about this? I'm not flying mine yet but will be getting ready to hang it soon.
For a summary on the fellow who made the presentation check out EAA AirVenture Oshkosh - The World's Greatest Aviation Celebration
EAA AirVenture Oshkosh - The World's Greatest Aviation Celebration
For all those who want to junk the Jab engine for as yet no clearly defined problems it would be good if you reflected on the Wright R3350 turbo compound engine used in the B29 and in the Super Constellation. When those engines were first used their TBO was typically 200 to 600 hours.Ouch
After they learned to operate them properly (essentially by running them lean of peak) they were often getting TBOs of 3,600 hours all with 1940s technology. Lycoming and Continental should hang their heads in shame.RA
Last edited by rutan around; 6th Sep 2013 at 22:29.
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The difference between the companies (Rotax & Jabiru) attitude to failures, in my personal experience, is chalk & cheese. Rotax 912 with approx 1300 hours had problems, symptoms indicated crankcase fretting, called dealer/factory... "We thought we had solved that issue, please send the engine in and we will replace the crankcase free of charge, we would like to get to the bottom of this...".
Jabiru 3300 in factory built aircraft at 280 hours, meticulously maintained etc. en-route ran rough for 10sec then stopped dead, found a flat bit of ground and walked away. Aircraft sent back to factory for repair by insurance Co. before we got a good look at the engine. When we asked what happened we were given the run-around, then we were accused of "thrashing" the engine, then they "lost" the bits, and when we insisted it be sent back did they said we could have a new engine for free minus rebate for hours. We never found out what went wrong (I suspect it dropped a valve).
One company seems to want to improve reliability, one want to cover its behind, ones reputation seems to be growing, one seems to be getting worse....
Jabiru 3300 in factory built aircraft at 280 hours, meticulously maintained etc. en-route ran rough for 10sec then stopped dead, found a flat bit of ground and walked away. Aircraft sent back to factory for repair by insurance Co. before we got a good look at the engine. When we asked what happened we were given the run-around, then we were accused of "thrashing" the engine, then they "lost" the bits, and when we insisted it be sent back did they said we could have a new engine for free minus rebate for hours. We never found out what went wrong (I suspect it dropped a valve).
One company seems to want to improve reliability, one want to cover its behind, ones reputation seems to be growing, one seems to be getting worse....