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teledynmcs(at)aol.com
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 Posted: Sat Jan 23, 2010 8:43 am Post subject: Jabiru engines |
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>>>>>Jabiru is not a good solution! I know many engines for sales in France replaced
by Rotax. <<Reliability>><<<<<
Greetings Team,
Once again, someone repeats negative rumors about the Jabiru 3300 without actual, hands on Jabiru experience. This happens virtually every time someone mentions a Jabiru engine on this forum and it's gone beyond being very tiresome and has crossed into vague, rumored bullshit.
What specifically were the problems you cite that caused the Jabiru engines you speak of to be unreliable and replaced with Rotaxs? Please elaborate. A little more info, rather than a broad, sweeping indictment and condemnation of Jabiru would be far more helpful. I personally know first hand of three Rotax 914's that have sustained broken cranks due to turbo over boost situations when the turbo waste gate stuck shut. I've also seen Rotax 912's with cracked cylinders, cracked and/or fretted cases, cracked exhaust, and spun main bearings due to improper oil purging during oil changes and I've heard second hand about a lot more issues. Anyone with a decent set of eyes can see that the Rotax is far, far more complicated than the Jabiru. For years now, right here on this very forum, I've read again and again of the trials and tribulations of Europaphiles and their various troubles with Rotax engines. Would it be fair for me to say that all Rotax engines are crap based on these events and forum posts? Of course not! It all boils down to how each engine is operated.
Some of the early Jabiru engines had reliability issues, mostly due to inadequate cooling because the cooling fins on the cylinder heads were too small. That is well known and the problems associated with that issue have been corrected. There was also a problem with the bolts fretting and breaking that attach the flywheel, but that has been narrowed down to engines that had sustained unreported prop strikes. This issue has likewise been corrected by installing pins between the flywheel and the crank in newer engines and replacing the flywheel bolts with stronger bolts and tighter torque on older engines. Similarly, although it's been a bit longer since the Rotax debuted and many who are new or relatively new to sport aviation may not remember or be aware, but many of the early Rotax 912/914 engines also had serious reliability issues. Read through the Rotax published SB's and AD's and familiarize yourself with the issues that have plagued the Rotax 912/914 series engines over the years before you bash Jabiru outright. Some of that stuff will curl your hair and make you think the Rotax 912/914 isn't suitable for use on a lawn mower. Why do you think there are dozens of Rotax Service Directives to comply with? Hint: it's not because the Rotax's were reliable in the early days of production!
In fact, the 912/914 still has reliability issues if not properly taken care of and Jabiru, Lycoming, Continental, Franklin, Subaru, Limbach, et al, are no different. Dozens, if not hundreds, of posts have been put up right here on this forum covering a wide range of reliability issues with the Rotax 912/914. These include, but are not limited to, engine cooling, carb issues, turbo issues, leaks, slipper clutch and redrive issues and ignition issues. You simply cannot run either of these engines with the wrong oil or improper cooling or the wrong prop loading or improper maintenance and expect a high degree of reliability. It just won't happen.
Just because the manufacturer's name is Rotax does not instantly mean bullet proof. Quite the contrary. Likewise, just because the manufacturer's name is Jabiru doesn't mean it's unreliable, but that theme seems to get repeated here adnauseum. This notion that overall the Jabiru 3300 engine is unreliable is a pure and unadulterated myth that continues to be repeated again and again here on this forum with little or nothing of substance to back up the claim. I personally know several dozen Jabiru owners who could not be happier with their engines, myself included. A while back the Jabiru 3300 with hydraulic lifters passed JAR certification. Unreliable? Funny, the JAR didn't seem to think so!
I have admitted I had some initial problems getting my CHT's to run cool, but that was my fault for not understanding how to make the head cooling work. I was blazing a new trail insofar as the cowl set and head ducts I was using and, at the time, there were only a handful of Europas flying with Jabiru engines installed. So, it stands to reason that, with little guidance, I would have some problems until I educated myself and got it all sorted out. That's why they call these things "experimental", right? I also had high EGT's initially, but again, that was my fault for not fully understanding the relationship between airframe drag, carb tuning, prop pitch and EGT's.
The Jabiru engine comes from the factory tuned specifically for the Jabiru airframe. If you hang a stock Jabiru engine on a much cleaner airframe, like a Europa, it presents less load to the engine throughout the RPM range and the result is the engine runs leaner. If this situation isn't corrected, you will have reliability issues, i.e., hotter EGT's and CHT's, burnt exhaust valves, etc. If you hang a stock Jabiru engine on a drag queen, like a CH701 or something similar, the load presented to the engine is greater and results in a richer running engine and reliability issues will result if not corrected, i.e., flooding, fouled plugs, etc.
Each operator/builder must carefully choose (or tune) the prop and tune the carb for your specific airframe in order to keep the engine happy and within approved operating parameters. You must also make sure that the heads get adequate cooling flow. Like purging the oil system on a Rotax with every oil change, this tuning is just something you have to do in order to make a Jabiru work properly in your airplane. In this incidence reliability has far more to do with the carburetor tuning and prop pitch as it relates to airframe drag than it does the engine itself. If you don't adjust the tuning to suit your airframe, yes, you are going to have problems, but is that Jabiru's fault? Hardly. Jabiru tells you exactly how to do it and if the owner doesn't comply it isn't Jabiru's fault. Period.
Graham, in regard to the intake plenum and turbulated flow entering the carb, I think you have it exactly backwards, at least insofar as the Jabiru/Bing set up is concerned and what I have learned from my own experience with this engine. I have a smooth bore radiator hose with a 90 degree bend that ducts air from my air filter box mounted on the firewall down and into the Bing carby on the back of the Jabiru. Initially, I had gross unevenness in my EGT's across the RPM range. I installed a vane (+) inside the intake plenum just up stream from the carby made from .025" stainless sheet to smooth out the airflow before it entered the carb. My EGT's went from a 200F hottest to coolest, to a spread down to about 50F just by installing this vane with no other change made. The airflow entering the Jabiru intake splitter downstream of the carb must be smooth in order to have even distribution of the fuel/air mixture to all cylinders. Turbulated air flow results in uneven EGT's.
It is also crucial that the prop be properly tuned (if adjustable) or chosen specifically for climb and cruise parameters (EGT vs RPM) for the airframe in order to achieve acceptable EGT's. By lowering the EGT's you also will affect the CHT's. Jabiru has published Service Bulletins on how to do this. Jabiru USA in Shelbyville offers a great 3 day course on the Jabiru engine that covers this topic in great depth. These guys really have this figured out. I highly recommend anyone considering this engine take this course. The knowledge you will gain is worth every penny of the $300 entry fee. Because Jabiru uses the Bing carb the 2200 and 3300 both are sensitive to prop and airframe loading, as well as carburetor tuning (jetting). Personally, I would love to see someone develop direct fuel injection for this engine. I tried a Rotec TBI, but I couldn't make it fit because of a conflict with the engine mounts. Some Jabiru owners, primarily Sonex builders, are using the Aerocarb, but there have been numerous problems reported with it. The Bing is basically a motorcycle carb and doesn't lend itself very well to this application unless properly tuned and even then it has shortcomings.
The 3300 is a powerful little engine. It's simple and robustly built, far simpler and more robust that the Rotax. I've seen first hand how both engines are built internally. For incidence, the Jabiru has main bearings between each con rod on the crank, not just on the ends and in the middle like a Rotax 912/914. The crank in the Jabiru is much better supported than the crank in the 912/914. A quick peek inside each engine and seeing how they are built won't leave you with a lot of confidence in the robustness of the Rotax, that is for sure. The parts for the Jabiru overall are cheaper, and many commonly replaceable parts are available at auto parts stores over the counter. If properly tuned and maintained, there is absolutely no reason why the Jabiru shouldn't be a very reliable engine in any airframe and a lot cheaper to operate than the Rotax, but you have to adjust the tuning to match your airframe combination in order to make it work.
I'm very pleased with my Jabiru, especially now that I have been through the Jabiru engine course and I fully understand how the engine is built, how the Bing carby operates and how to tune it and the prop for airframe drag (or lack thereof). My Europa is a trigear. I'm running a Sensenich carbon ground adjustable prop. I do not have straight pipes, but I do have the newer 3 into 1 exhaust manifold arrangement with an expansion chamber (muffler) and a single exhaust stack. I see climb rates solo a bit over 1800 fpm and 1400 fpm with two on board with full fuel and full baggage. I cruise at 128-130 kts at 5 gph. Top speed at WOT is a bit over 160 kts indicated, all for $12,000 less than the Rotax.
FWIW, just so everyone will know that I have nothing against Rotax. As I have mentioned here before I also own an Aeromot Ximango AMT200S motorglider. My Ximango has a certified 912S installed. I compare the Jabiru 3300 to the Rotax 912S on an almost daily basis (except now because it's January and the weather is crap). I've been comparing these engines directly from both an operational and maintenance standpoint for nearly three years now. I cannot see any distinct advantage of the Rotax over the Jabiru or vice versa in these direct comparisons. Several things I have noticed are worth mentioning, though.
The Rotax engines are very expensive for those of us on this side of the pond with the current exchange rate. Likewise, Rotax parts, when compared to Jabiru parts, are definitely more expensive, much more expensive. Oil changes with the Rotax are a pain in the ass compared to changing the oil in the Jabiru. The Rotax is a far, far more complicated engine when compared to the Jabiru. If you believe in the K.I.S.S. principle for aviation related components, this bodes well for the Jabiru. The Rotax is probably a better choice for my motorglider because the wet heads help slow the engine cooling, avoiding shock cooling, when I shut the engine down to soar after climbing to usable lift. There is no second carburetor on the Jabiru to keep in sync as with the Rotax. With the Jabiru, set it and forget it. The Jabiru has fixed timing with simple, dual distributors, as opposed to an $800 ignition module that will leave you stranded if and when it fails. My 3300 is a solid lifter version and I do have to torque the heads and keep the valve tappet clearance adjusted regularly. I time that maintenance with my oil changes and can easily torque the heads and adjust the valves while the oil is draining with time to spare. Otherwise, I'm really enjoying the extra 30 or so HP that the Jabiru offers my Europa over the 912S. I also like the throaty, real airplane engine sound of the Jabiru over the whiny noise the Rotax makes. The Jabiru is also a far, far smoother running engine with MUCH less vibration than the Rotax. I say this not only from a pilot feel standpoint, but also because I've had both props balanced using an ACER Probalancer. Interestingly, my Jabiru needed no further adjustments to achieve perfect balance. The Rotax required some counter weights to balance the prop.
So, with all this said, enough already with this second hand Jabiru bashing. If you have specific, first hand experience with issues regarding the Jabiru 3300, let's hear 'em and we'll talk about it. Broad based condemnation of either engine is useless to everyone and only fuels the rumor mill. IMHO, the Jabiru 3300 is a fine little engine and if I had it to do all over again I would indeed buy another Jabiru for my Europa. My experience and the experiences related to me by the fine folks at Jabiru USA and Lightning Aircraft in Shelbyville, TN, show that, more often than not, it is the operators that have the problem because they aren't tuning the prop and carb to suit their airframes or they are running the wrong oil or they are allowing the engine to run hot, or otherwise abusing or not properly maintaining the engine. I can cite literally dozens of failures in Rotax's that have resulted from the same sort of abuse if you'd like, but you can learn about them yourself by reading through the Rotax SB's and AD's.
BTW, anyone who is interested please note that my email is changing at the end of the month. My new email will be wingdingy(at)gmail.com (wingdingy(at)gmail.com). This address is up and running now. Sorry for the inconvenience.
Regards,
John Lawton
Whitwell, TN (TN89)
N245E - Flying and lovin' every minute of it!
[quote][b]
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Jeff(at)rmmm.net
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| Posted: Sat Jan 23, 2010 9:19 am Post subject: Jabiru engines |
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Right on the money John!!!!!
Jeff R. N128LJ Gold Rush 912-S
On Jan 23, 2010, at 10:39 AM, teledynmcs(at)aol.com (teledynmcs(at)aol.com) wrote:
| Quote: | >>>>>Jabiru is not a good solution! I know many engines for sales in France replaced
by Rotax. <<Reliability>><<<<<
Greetings Team,
Once again, someone repeats negative rumors about the Jabiru 3300 without actual, hands on Jabiru experience. This happens virtually every time someone mentions a Jabiru engine on this forum and it's gone beyond being very tiresome and has crossed into vague, rumored bullshit.
What specifically were the problems you cite that caused the Jabiru engines you speak of to be unreliable and replaced with Rotaxs? Please elaborate. A little more info, rather than a broad, sweeping indictment and condemnation of Jabiru would be far more helpful. I personally know first hand of three Rotax 914's that have sustained broken cranks due to turbo over boost situations when the turbo waste gate stuck shut. I've also seen Rotax 912's with cracked cylinders, cracked and/or fretted cases, cracked exhaust, and spun main bearings due to improper oil purging during oil changes and I've heard second hand about a lot more issues. Anyone with a decent set of eyes can see that the Rotax is far, far more complicated than the Jabiru. For years now, right here on this very forum, I've read again and again of the trials and tribulations of Europaphiles and their various troubles with Rotax engines. Would it be fair for me to say that all Rotax engines are crap based on these events and forum posts? Of course not! It all boils down to how each engine is operated.
Some of the early Jabiru engines had reliability issues, mostly due to inadequate cooling because the cooling fins on the cylinder heads were too small. That is well known and the problems associated with that issue have been corrected. There was also a problem with the bolts fretting and breaking that attach the flywheel, but that has been narrowed down to engines that had sustained unreported prop strikes. This issue has likewise been corrected by installing pins between the flywheel and the crank in newer engines and replacing the flywheel bolts with stronger bolts and tighter torque on older engines. Similarly, although it's been a bit longer since the Rotax debuted and many who are new or relatively new to sport aviation may not remember or be aware, but many of the early Rotax 912/914 engines also had serious reliability issues. Read through the Rotax published SB's and AD's and familiarize yourself with the issues that have plagued the Rotax 912/914 series engines over the years before you bash Jabiru outright. Some of that stuff will curl your hair and make you think the Rotax 912/914 isn't suitable for use on a lawn mower. Why do you think there are dozens of Rotax Service Directives to comply with? Hint: it's not because the Rotax's were reliable in the early days of production!
In fact, the 912/914 still has reliability issues if not properly taken care of and Jabiru, Lycoming, Continental, Franklin, Subaru, Limbach, et al, are no different. Dozens, if not hundreds, of posts have been put up right here on this forum covering a wide range of reliability issues with the Rotax 912/914. These include, but are not limited to, engine cooling, carb issues, turbo issues, leaks, slipper clutch and redrive issues and ignition issues. You simply cannot run either of these engines with the wrong oil or improper cooling or the wrong prop loading or improper maintenance and expect a high degree of reliability. It just won't happen.
Just because the manufacturer's name is Rotax does not instantly mean bullet proof. Quite the contrary. Likewise, just because the manufacturer's name is Jabiru doesn't mean it's unreliable, but that theme seems to get repeated here adnauseum. This notion that overall the Jabiru 3300 engine is unreliable is a pure and unadulterated myth that continues to be repeated again and again here on this forum with little or nothing of substance to back up the claim. I personally know several dozen Jabiru owners who could not be happier with their engines, myself included. A while back the Jabiru 3300 with hydraulic lifters passed JAR certification. Unreliable? Funny, the JAR didn't seem to think so!
I have admitted I had some initial problems getting my CHT's to run cool, but that was my fault for not understanding how to make the head cooling work. I was blazing a new trail insofar as the cowl set and head ducts I was using and, at the time, there were only a handful of Europas flying with Jabiru engines installed. So, it stands to reason that, with little guidance, I would have some problems until I educated myself and got it all sorted out. That's why they call these things "experimental", right? I also had high EGT's initially, but again, that was my fault for not fully understanding the relationship between airframe drag, carb tuning, prop pitch and EGT's.
The Jabiru engine comes from the factory tuned specifically for the Jabiru airframe. If you hang a stock Jabiru engine on a much cleaner airframe, like a Europa, it presents less load to the engine throughout the RPM range and the result is the engine runs leaner. If this situation isn't corrected, you will have reliability issues, i.e., hotter EGT's and CHT's, burnt exhaust valves, etc. If you hang a stock Jabiru engine on a drag queen, like a CH701 or something similar, the load presented to the engine is greater and results in a richer running engine and reliability issues will result if not corrected, i.e., flooding, fouled plugs, etc.
Each operator/builder must carefully choose (or tune) the prop and tune the carb for your specific airframe in order to keep the engine happy and within approved operating parameters. You must also make sure that the heads get adequate cooling flow. Like purging the oil system on a Rotax with every oil change, this tuning is just something you have to do in order to make a Jabiru work properly in your airplane. In this incidence reliability has far more to do with the carburetor tuning and prop pitch as it relates to airframe drag than it does the engine itself. If you don't adjust the tuning to suit your airframe, yes, you are going to have problems, but is that Jabiru's fault? Hardly. Jabiru tells you exactly how to do it and if the owner doesn't comply it isn't Jabiru's fault. Period.
Graham, in regard to the intake plenum and turbulated flow entering the carb, I think you have it exactly backwards, at least insofar as the Jabiru/Bing set up is concerned and what I have learned from my own experience with this engine. I have a smooth bore radiator hose with a 90 degree bend that ducts air from my air filter box mounted on the firewall down and into the Bing carby on the back of the Jabiru. Initially, I had gross unevenness in my EGT's across the RPM range. I installed a vane (+) inside the intake plenum just up stream from the carby made from .025" stainless sheet to smooth out the airflow before it entered the carb. My EGT's went from a 200F hottest to coolest, to a spread down to about 50F just by installing this vane with no other change made. The airflow entering the Jabiru intake splitter downstream of the carb must be smooth in order to have even distribution of the fuel/air mixture to all cylinders. Turbulated air flow results in uneven EGT's.
It is also crucial that the prop be properly tuned (if adjustable) or chosen specifically for climb and cruise parameters (EGT vs RPM) for the airframe in order to achieve acceptable EGT's. By lowering the EGT's you also will affect the CHT's. Jabiru has published Service Bulletins on how to do this. Jabiru USA in Shelbyville offers a great 3 day course on the Jabiru engine that covers this topic in great depth. These guys really have this figured out. I highly recommend anyone considering this engine take this course. The knowledge you will gain is worth every penny of the $300 entry fee. Because Jabiru uses the Bing carb the 2200 and 3300 both are sensitive to prop and airframe loading, as well as carburetor tuning (jetting). Personally, I would love to see someone develop direct fuel injection for this engine. I tried a Rotec TBI, but I couldn't make it fit because of a conflict with the engine mounts. Some Jabiru owners, primarily Sonex builders, are using the Aerocarb, but there have been numerous problems reported with it. The Bing is basically a motorcycle carb and doesn't lend itself very well to this application unless properly tuned and even then it has shortcomings.
The 3300 is a powerful little engine. It's simple and robustly built, far simpler and more robust that the Rotax. I've seen first hand how both engines are built internally. For incidence, the Jabiru has main bearings between each con rod on the crank, not just on the ends and in the middle like a Rotax 912/914. The crank in the Jabiru is much better supported than the crank in the 912/914. A quick peek inside each engine and seeing how they are built won't leave you with a lot of confidence in the robustness of the Rotax, that is for sure. The parts for the Jabiru overall are cheaper, and many commonly replaceable parts are available at auto parts stores over the counter. If properly tuned and maintained, there is absolutely no reason why the Jabiru shouldn't be a very reliable engine in any airframe and a lot cheaper to operate than the Rotax, but you have to adjust the tuning to match your airframe combination in order to make it work.
I'm very pleased with my Jabiru, especially now that I have been through the Jabiru engine course and I fully understand how the engine is built, how the Bing carby operates and how to tune it and the prop for airframe drag (or lack thereof). My Europa is a trigear. I'm running a Sensenich carbon ground adjustable prop. I do not have straight pipes, but I do have the newer 3 into 1 exhaust manifold arrangement with an expansion chamber (muffler) and a single exhaust stack. I see climb rates solo a bit over 1800 fpm and 1400 fpm with two on board with full fuel and full baggage. I cruise at 128-130 kts at 5 gph. Top speed at WOT is a bit over 160 kts indicated, all for $12,000 less than the Rotax.
FWIW, just so everyone will know that I have nothing against Rotax. As I have mentioned here before I also own an Aeromot Ximango AMT200S motorglider. My Ximango has a certified 912S installed. I compare the Jabiru 3300 to the Rotax 912S on an almost daily basis (except now because it's January and the weather is crap). I've been comparing these engines directly from both an operational and maintenance standpoint for nearly three years now. I cannot see any distinct advantage of the Rotax over the Jabiru or vice versa in these direct comparisons. Several things I have noticed are worth mentioning, though.
The Rotax engines are very expensive for those of us on this side of the pond with the current exchange rate. Likewise, Rotax parts, when compared to Jabiru parts, are definitely more expensive, much more expensive. Oil changes with the Rotax are a pain in the ass compared to changing the oil in the Jabiru. The Rotax is a far, far more complicated engine when compared to the Jabiru. If you believe in the K.I.S.S. principle for aviation related components, this bodes well for the Jabiru. The Rotax is probably a better choice for my motorglider because the wet heads help slow the engine cooling, avoiding shock cooling, when I shut the engine down to soar after climbing to usable lift. There is no second carburetor on the Jabiru to keep in sync as with the Rotax. With the Jabiru, set it and forget it. The Jabiru has fixed timing with simple, dual distributors, as opposed to an $800 ignition module that will leave you stranded if and when it fails. My 3300 is a solid lifter version and I do have to torque the heads and keep the valve tappet clearance adjusted regularly. I time that maintenance with my oil changes and can easily torque the heads and adjust the valves while the oil is draining with time to spare. Otherwise, I'm really enjoying the extra 30 or so HP that the Jabiru offers my Europa over the 912S. I also like the throaty, real airplane engine sound of the Jabiru over the whiny noise the Rotax makes. The Jabiru is also a far, far smoother running engine with MUCH less vibration than the Rotax. I say this not only from a pilot feel standpoint, but also because I've had both props balanced using an ACER Probalancer. Interestingly, my Jabiru needed no further adjustments to achieve perfect balance. The Rotax required some counter weights to balance the prop.
So, with all this said, enough already with this second hand Jabiru bashing. If you have specific, first hand experience with issues regarding the Jabiru 3300, let's hear 'em and we'll talk about it. Broad based condemnation of either engine is useless to everyone and only fuels the rumor mill. IMHO, the Jabiru 3300 is a fine little engine and if I had it to do all over again I would indeed buy another Jabiru for my Europa. My experience and the experiences related to me by the fine folks at Jabiru USA and Lightning Aircraft in Shelbyville, TN, show that, more often than not, it is the operators that have the problem because they aren't tuning the prop and carb to suit their airframes or they are running the wrong oil or they are allowing the engine to run hot, or otherwise abusing or not properly maintaining the engine. I can cite literally dozens of failures in Rotax's that have resulted from the same sort of abuse if you'd like, but you can learn about them yourself by reading through the Rotax SB's and AD's.
BTW, anyone who is interested please note that my email is changing at the end of the month. My new email will be wingdingy(at)gmail.com (wingdingy(at)gmail.com). This address is up and running now. Sorry for the inconvenience.
Regards,
John Lawton
Whitwell, TN (TN89)
N245E - Flying and lovin' every minute of it!
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gdh(at)isp.com
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| Posted: Sat Jan 23, 2010 10:42 am Post subject: Jabiru engines |
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On 1/23/2010 8:39 AM, teledynmcs(at)aol.com (teledynmcs(at)aol.com) wrote: | Quote: | >>>>>Jabiru is not a good solution! I know many engines for sales in France replaced
by Rotax. <<Reliability>><<<<<
Greetings Team,
Once again, someone repeats negative rumors about the Jabiru 3300 without actual, hands on Jabiru experience. This happens virtually every time someone mentions a Jabiru engine on this forum and it's gone beyond being very tiresome and has crossed into vague, rumored bullshit.
What specifically were the problems you cite that caused the Jabiru engines you speak of to be unreliable and replaced with Rotaxs? Please elaborate. A little more info, rather than a broad, sweeping indictment and condemnation of Jabiru would be far more helpful. I personally know first hand of three Rotax 914's that have sustained broken cranks due to turbo over boost situations when the turbo waste gate stuck shut. I've also seen Rotax 912's with cracked cylinders, cracked and/or fretted cases, cracked exhaust, and spun main bearings due to improper oil purging during oil changes and I've heard second hand about a lot more issues. Anyone with a decent set of eyes can see that the Rotax is far, far more complicated than the Jabiru. For years now, right here on this very forum, I've read again and again of the trials and tribulations of Europaphiles and their various troubles with Rotax engines. Would it be fair for me to say that all Rotax engines are crap based on these events and forum posts? Of course not! It all boils down to how each engine is operated.
Some of the early Jabiru engines had reliability issues, mostly due to inadequate cooling because the cooling fins on the cylinder heads were too small. That is well known and the problems associated with that issue have been corrected. There was also a problem with the bolts fretting and breaking that attach the flywheel, but that has been narrowed down to engines that had sustained unreported prop strikes. This issue has likewise been corrected by installing pins between the flywheel and the crank in newer engines and replacing the flywheel bolts with stronger bolts and tighter torque on older engines. Similarly, although it's been a bit longer since the Rotax debuted and many who are new or relatively new to sport aviation may not remember or be aware, but many of the early Rotax 912/914 engines also had serious reliability issues. Read through the Rotax published SB's and AD's and familiarize yourself with the issues that have plagued the Rotax 912/914 series engines over the years before you bash Jabiru outright. Some of that stuff will curl your hair and make you think the Rotax 912/914 isn't suitable for use on a lawn mower. Why do you think there are dozens of Rotax Service Directives to comply with? Hint: it's not because the Rotax's were reliable in the early days of production!
In fact, the 912/914 still has reliability issues if not properly taken care of and Jabiru, Lycoming, Continental, Franklin, Subaru, Limbach, et al, are no different. Dozens, if not hundreds, of posts have been put up right here on this forum covering a wide range of reliability issues with the Rotax 912/914. These include, but are not limited to, engine cooling, carb issues, turbo issues, leaks, slipper clutch and redrive issues and ignition issues. You simply cannot run either of these engines with the wrong oil or improper cooling or the wrong prop loading or improper maintenance and expect a high degree of reliability. It just won't happen.
Just because the manufacturer's name is Rotax does not instantly mean bullet proof. Quite the contrary. Likewise, just because the manufacturer's name is Jabiru doesn't mean it's unreliable, but that theme seems to get repeated here adnauseum. This notion that overall the Jabiru 3300 engine is unreliable is a pure and unadulterated myth that continues to be repeated again and again here on this forum with little or nothing of substance to back up the claim. I personally know several dozen Jabiru owners who could not be happier with their engines, myself included. A while back the Jabiru 3300 with hydraulic lifters passed JAR certification. Unreliable? Funny, the JAR didn't seem to think so!
I have admitted I had some initial problems getting my CHT's to run cool, but that was my fault for not understanding how to make the head cooling work. I was blazing a new trail insofar as the cowl set and head ducts I was using and, at the time, there were only a handful of Europas flying with Jabiru engines installed. So, it stands to reason that, with little guidance, I would have some problems until I educated myself and got it all sorted out. That's why they call these things "experimental", right? I also had high EGT's initially, but again, that was my fault for not fully understanding the relationship between airframe drag, carb tuning, prop pitch and EGT's.
The Jabiru engine comes from the factory tuned specifically for the Jabiru airframe. If you hang a stock Jabiru engine on a much cleaner airframe, like a Europa, it presents less load to the engine throughout the RPM range and the result is the engine runs leaner. If this situation isn't corrected, you will have reliability issues, i.e., hotter EGT's and CHT's, burnt exhaust valves, etc. If you hang a stock Jabiru engine on a drag queen, like a CH701 or something similar, the load presented to the engine is greater and results in a richer running engine and reliability issues will result if not corrected, i.e., flooding, fouled plugs, etc.
Each operator/builder must carefully choose (or tune) the prop and tune the carb for your specific airframe in order to keep the engine happy and within approved operating parameters. You must also make sure that the heads get adequate cooling flow. Like purging the oil system on a Rotax with every oil change, this tuning is just something you have to do in order to make a Jabiru work properly in your airplane. In this incidence reliability has far more to do with the carburetor tuning and prop pitch as it relates to airframe drag than it does the engine itself. If you don't adjust the tuning to suit your airframe, yes, you are going to have problems, but is that Jabiru's fault? Hardly. Jabiru tells you exactly how to do it and if the owner doesn't comply it isn't Jabiru's fault. Period.
Graham, in regard to the intake plenum and turbulated flow entering the carb, I think you have it exactly backwards, at least insofar as the Jabiru/Bing set up is concerned and what I have learned from my own experience with this engine. I have a smooth bore radiator hose with a 90 degree bend that ducts air from my air filter box mounted on the firewall down and into the Bing carby on the back of the Jabiru. Initially, I had gross unevenness in my EGT's across the RPM range. I installed a vane (+) inside the intake plenum just up stream from the carby made from .025" stainless sheet to smooth out the airflow before it entered the carb. My EGT's went from a 200F hottest to coolest, to a spread down to about 50F just by installing this vane with no other change made. The airflow entering the Jabiru intake splitter downstream of the carb must be smooth in order to have even distribution of the fuel/air mixture to all cylinders. Turbulated air flow results in uneven EGT's.
It is also crucial that the prop be properly tuned (if adjustable) or chosen specifically for climb and cruise parameters (EGT vs RPM) for the airframe in order to achieve acceptable EGT's. By lowering the EGT's you also will affect the CHT's. Jabiru has published Service Bulletins on how to do this. Jabiru USA in Shelbyville offers a great 3 day course on the Jabiru engine that covers this topic in great depth. These guys really have this figured out. I highly recommend anyone considering this engine take this course. The knowledge you will gain is worth every penny of the $300 entry fee. Because Jabiru uses the Bing carb the 2200 and 3300 both are sensitive to prop and airframe loading, as well as carburetor tuning (jetting). Personally, I would love to see someone develop direct fuel injection for this engine. I tried a Rotec TBI, but I couldn't make it fit because of a conflict with the engine mounts. Some Jabiru owners, primarily Sonex builders, are using the Aerocarb, but there have been numerous problems reported with it. The Bing is basically a motorcycle carb and doesn't lend itself very well to this application unless properly tuned and even then it has shortcomings.
The 3300 is a powerful little engine. It's simple and robustly built, far simpler and more robust that the Rotax. I've seen first hand how both engines are built internally. For incidence, the Jabiru has main bearings between each con rod on the crank, not just on the ends and in the middle like a Rotax 912/914. The crank in the Jabiru is much better supported than the crank in the 912/914. A quick peek inside each engine and seeing how they are built won't leave you with a lot of confidence in the robustness of the Rotax, that is for sure. The parts for the Jabiru overall are cheaper, and many commonly replaceable parts are available at auto parts stores over the counter. If properly tuned and maintained, there is absolutely no reason why the Jabiru shouldn't be a very reliable engine in any airframe and a lot cheaper to operate than the Rotax, but you have to adjust the tuning to match your airframe combination in order to make it work.
I'm very pleased with my Jabiru, especially now that I have been through the Jabiru engine course and I fully understand how the engine is built, how the Bing carby operates and how to tune it and the prop for airframe drag (or lack thereof). My Europa is a trigear. I'm running a Sensenich carbon ground adjustable prop. I do not have straight pipes, but I do have the newer 3 into 1 exhaust manifold arrangement with an expansion chamber (muffler) and a single exhaust stack. I see climb rates solo a bit over 1800 fpm and 1400 fpm with two on board with full fuel and full baggage. I cruise at 128-130 kts at 5 gph. Top speed at WOT is a bit over 160 kts indicated, all for $12,000 less than the Rotax.
FWIW, just so everyone will know that I have nothing against Rotax. As I have mentioned here before I also own an Aeromot Ximango AMT200S motorglider. My Ximango has a certified 912S installed. I compare the Jabiru 3300 to the Rotax 912S on an almost daily basis (except now because it's January and the weather is crap). I've been comparing these engines directly from both an operational and maintenance standpoint for nearly three years now. I cannot see any distinct advantage of the Rotax over the Jabiru or vice versa in these direct comparisons. Several things I have noticed are worth mentioning, though.
The Rotax engines are very expensive for those of us on this side of the pond with the current exchange rate. Likewise, Rotax parts, when compared to Jabiru parts, are definitely more expensive, much more expensive. Oil changes with the Rotax are a pain in the ass compared to changing the oil in the Jabiru. The Rotax is a far, far more complicated engine when compared to the Jabiru. If you believe in the K.I.S.S. principle for aviation related components, this bodes well for the Jabiru. The Rotax is probably a better choice for my motorglider because the wet heads help slow the engine cooling, avoiding shock cooling, when I shut the engine down to soar after climbing to usable lift. There is no second carburetor on the Jabiru to keep in sync as with the Rotax. With the Jabiru, set it and forget it. The Jabiru has fixed timing with simple, dual distributors, as opposed to an $800 ignition module that will leave you stranded if and when it fails. My 3300 is a solid lifter version and I do have to torque the heads and keep the valve tappet clearance adjusted regularly. I time that maintenance with my oil changes and can easily torque the heads and adjust the valves while the oil is draining with time to spare. Otherwise, I'm really enjoying the extra 30 or so HP that the Jabiru offers my Europa over the 912S. I also like the throaty, real airplane engine sound of the Jabiru over the whiny noise the Rotax makes. The Jabiru is also a far, far smoother running engine with MUCH less vibration than the Rotax. I say this not only from a pilot feel standpoint, but also because I've had both props balanced using an ACER Probalancer. Interestingly, my Jabiru needed no further adjustments to achieve perfect balance. The Rotax required some counter weights to balance the prop.
So, with all this said, enough already with this second hand Jabiru bashing. If you have specific, first hand experience with issues regarding the Jabiru 3300, let's hear 'em and we'll talk about it. Broad based condemnation of either engine is useless to everyone and only fuels the rumor mill. IMHO, the Jabiru 3300 is a fine little engine and if I had it to do all over again I would indeed buy another Jabiru for my Europa. My experience and the experiences related to me by the fine folks at Jabiru USA and Lightning Aircraft in Shelbyville, TN, show that, more often than not, it is the operators that have the problem because they aren't tuning the prop and carb to suit their airframes or they are running the wrong oil or they are allowing the engine to run hot, or otherwise abusing or not properly maintaining the engine. I can cite literally dozens of failures in Rotax's that have resulted from the same sort of abuse if you'd like, but you can learn about them yourself by reading through the Rotax SB's and AD's.
BTW, anyone who is interested please note that my email is changing at the end of the month. My new email will be wingdingy(at)gmail.com (wingdingy(at)gmail.com). This address is up and running now. Sorry for the inconvenience.
Regards,
John Lawton
Whitwell, TN (TN89)
N245E - Flying and lovin' every minute of it!
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Dale
Europa Tri-Gear
Jab 3300
[quote] | Quote: |
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href="http://forums.matronics.com">http://forums.matronics.com
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fklein(at)orcasonline.com
Guest
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| Posted: Sat Jan 23, 2010 10:45 am Post subject: Jabiru engines |
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Begin forwarded message:
[quote]From: Fred Klein <fklein(at)orcasonline.com (fklein(at)orcasonline.com)>
Date: January 23, 2010 9:39:19 AM PST
To: John Lawton <wingdingy(at)gmail.com (wingdingy(at)gmail.com)>
Subject: Re: Jabiru engines
John...I thought this might get your attention...nice reply...I appreciate it when you put your oar in...when you do, IMHO, the value of the forum skyrockets...Fred
| Quote: | On Jan 23, 2010, at 10:39 AM, teledynmcs(at)aol.com (teledynmcs(at)aol.com) wrote:
| Quote: | >>>>>Jabiru is not a good solution! I know many engines for sales in France replaced
by Rotax. <<Reliability>><<<<<
Greetings Team,
Once again, someone repeats negative rumors about the Jabiru 3300 without actual, hands on Jabiru experience.
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kevann(at)gotsky.com
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Gilles.Thesee(at)ac-greno
Guest
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| Posted: Sat Jan 23, 2010 9:02 pm Post subject: Jabiru engines |
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John and all,
Thank you for your message. What is most important is that fact that you
are satisfied with your engine.
I would beg to differ with some of the arguments you exposed.
| Quote: | A while back the Jabiru 3300 with hydraulic lifters passed JAR
certification. Unreliable? Funny, the JAR didn't seem to think so!
Nothing to do with the Jabiru, but we should be aware that an engine
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certification doesn't necessarily imply "real life" reliability. Just
think of the Thielert or JPX engines.
| Quote: |
Like purging the oil system on a Rotax with every oil change, this
tuning is just something you have to do
You just don't purge anything when changing oil on a Rotax : drain the
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oil tank, put a new seal and filter, and pour fresh oil. We installed a
quick drain valve so the total time for an oil change is about 10
minutes including removing and reinstalling the cowling.
| Quote: | The 3300 is a powerful little engine. It's simple and robustly built,
far simpler and more robust that the Rotax. I've seen first hand how
both engines are built internally. For incidence, the Jabiru has main
bearings between each con rod on the crank, not just on the ends and
in the middle like a Rotax 912/914. The crank in the Jabiru is much
better supported than the crank in the 912/914. A quick peek inside
each engine and seeing how they are built won't leave you with a lot
of confidence in the robustness of the Rotax, that is for sure.
I too had the opportunity to examine the internals of bothe engines.
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It is true that the Jabiru is simpler and far more lightly built than
the Rotax, but in my opinion there is nothing wrong with a short
assembled crankshaft in a rigid crankcase. Radial engines too have short
assembled crankshafts, and some of them are among the most reliable
piston engines in aviation.
Besides, there are no specific crankshaft related failures on the Rotax,
nor the Jabiru for that matter.
| Quote: | Why do you think there are dozens of Rotax Service Directives to
comply with? Hint: it's not because the Rotax's were reliable in the
early days of production!
Any serious engine manufacturer SHOULD issue dozens of SBs, SLs, etc...
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| Quote: |
The Rotax engines are very expensive for those of us on this side of
the pond with the current exchange rate. Likewise, Rotax parts, when
compared to Jabiru parts, are definitely more expensive, much more
expensive.
Agreed.
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| Quote: | Oil changes with the Rotax are a pain in the ass compared to changing
the oil in the Jabiru.
This is just not so, see above.
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| Quote: | The Rotax is a far, far more complicated engine when compared to the
Jabiru. If you believe in the K.I.S.S. principle for aviation related
components, this bodes well for the Jabiru.
Lord Hives, manager of Rolls-Royce during the war said to Franck Whittle
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: "Give us your jet engine project, and we will soon design the
simplicity out of it "
The early Jabiru were simple, but with time, they now have many many
more parts : hydraulic lifters, cam follower, crankshaft dowels, etc...
Many owners are afraid of the maze of coolant lines on a Rotax. But your
car has many of them too, albeit better concealed from view. And yet
would one say car engines are unreliable ?
What counts for an aero engines, is the thousands of operating hours to
make it reliable, not this or that mechanical choice (as long as it is a
sound choice).
| Quote: | I also like the throaty, real airplane engine sound of the Jabiru over
the whiny noise the Rotax makes.
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Think of us poor pilots in densely populated Europe. We must overfly
thousands of people, and they don't like noise !
Rotax engines can be very quiet with their slow turning props.
Just my thoughts,
Best regards,
--
Gilles
http://contrails.free.fr
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topglock(at)cox.net
Guest
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| Posted: Sun Jan 24, 2010 11:05 am Post subject: Jabiru engines |
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Actually, there are a few documented instances where the pressed Rotax
cranks have slipped, slightly, throwing the piston timing off enough to
cause vibrations. Granted, this is the exception, but it does exist...
Jeff - Baby Blue
Gilles Thesee wrote:
.. there are no specific crankshaft related failures on the Rotax,
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creightonious
Joined: 10 Mar 2007
Posts: 40
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| Posted: Sun Jan 24, 2010 11:14 am Post subject: Jabiru engines |
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Lots of good stuff. Thanks John and Gilles and others.
One thing about Jabiru installation perplexes me: Every Jabiru installation I have looked at over the years has had presumed cooling issues addressed with little deflectors inside the cooling cowl which is part of the engine package.
This is heartening since it shows they (Jabiru) have been paying attention. The perplexing thing is: why is there no provision for inter-cylinder baffling? Every air cooled engine I've ever seen has these. (Lycoming, Continental, Franklin, de Haviland, Ranger, LOM, P&W, VW, Porsche... all except Jabiru, free air or fan cooled.
Not only for cylinder and head temps, but for cooling drag reduction it is a good thing to make all the air entering the cowling do good, efficient work removing heat from the engine.
Why? What am I/we missing? Jabiru installations have huge passages between cylinders and heads so a lot of air rushes through (because there's less resistance) rather than being directed through the head and cylinder finning.
I also agree that the Jabiru would benefit enormously from a 6-point fuel injection system. Or perhaps 2 of the Rotec "injectors". It is really hard to evenly distribute the relatively large fuel droplets emerging from the Bing's mainjet well through the Jabiru's long, serpentine induction passages. Liquid doesn't go around corners, it sheets out on the outside of bends and crawls downstream.
The major users of diaphragm (constant velocity) carbs, (Bing, Mikuni, Keihin) are motorcycles and outboards and they are mounted on a straight through manifold as close to the intake valve as practicable. Not the case on Rotax or, especially, Jabiru.
Sorry for the verbosity.
Creighton Smith
A-036
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Creighton Smith
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Roland
Joined: 30 Nov 2009
Posts: 334
Location: EDLE
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| Posted: Tue Jan 26, 2010 8:58 am Post subject: Re: Jabiru engines |
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Rotax extended TBO for the 912 series to 2000 h and 15 years. More than 30.000 built by now. No need to say more.
But I have to add, that I cannot say anything against the Jabiru.
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