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Jabiru engines.

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TELEDYNMCS(at)aol.com
Guest

Posted: Tue Jan 26, 2010 6:43 am Post subject: Jabiru engines.

 	  Quote: 	
		  



 	  Quote: 	
		  >>>You    just don't purge anything when changing oil on a Rotax : drain the

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.<<<<

	


 



Hello Giles, 



It might behoove you to take a look  at the Rotax Service Instruction on the 912 that came out last March (2009)  regarding oil changes. Specifically, SI-912-10R3 dated March 19, 2009. This SI  runs concurrent with SI 912-018 entitled "Purging of Lubrication System" In SI  912-018, it specifically describes how to purge the oil system when changing the  oil in a 912/914 to remove old oil and then how to rebleed the system with new  oil. Doing this procedures ensures that the journals, bearings, rocker arms, etc  are all properly lubricated prior to start up after the oil change. SI 912-010  R3 reiterates this method because so many Rotax 912/914 owners have not been  following the proper oil change procedure and bearing failures, among other  things, have resulted. Kerry down at Lockwood in Florida told me that if  you aren't doing this procedure "you are asking for trouble".  There  is a similar SI issued for the 914 with the same date. Some people refer to this  procedure as "burping the engine" because of the noise it makes when you are  purging. You can simply drain the oil from the tank, change the filter and  refill with new oil, but you are leaving nearly a quart of old oil in the engine  and lines if you do it that way. I'm not that familiar with the 912/914  configuration as it exists in the Europa, but that is nearly 1/3rd of the oil in  my Ximango 912S oil system. Leaving 1/3rd of tht old oil in the lines  and engine kind of defeats the purpose of doing an oil change, doesn't  it?

 

 	  Quote: 	
		  >>>>Any serious engine manufacturer SHOULD  issue dozens of SBs, SLs, etc...<<<<<


	


 

Agreed. Rotax does do a fine job of documenting their failures and  resulting maintenance procedures and engine enhancements. This is why I  suggested to those who repeat the negative rumors about Jabiru engines to do  some reading and understand the history of their Rotax engines. I remember quite  well when the first 912's came out. They were much better boat anchors than  airplane engines. Rotax had all sorts of problems with it, but it has been  so long that many might not remember or be aware. My point was the 912/914  platform has it's own sorted history of failures and those failures continue to  this day if you don't follow Rotax maintenance procedures to the  letter. 



 The way the Jabiru engine is spoken of here on this  forum it's as if it is the only aircraft engine ever built that has had  some growing pains after initial release. Many here seem to think those growing  pains suffered in the early engines have not been corrected and as a result they  are not reliable engines. Nothing could be farther from the truth. The Jabiru  engine continues to be refined, just like the Rotax 912/914 and it has proven to  be at least as reliable as the Rotax, if not more so because it is so simple,  but, as with any aircraft engine you have to tune it for your airframe for  best results. 



 	  Quote: 	
		  >>>Lord Hives, manager of Rolls-Royce  during the war said to Franck Whittle

: "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...<<<<<



 

The Jabiru USA folks spent about 2 hours the first day of the 3 day  class going over the design goals of the engine, it's history, and all the  refinements that have been done to the Jabiru 2200 and 3300 since they were  released and why. They spent another couple of hours going over the  various failures that they have seen over the years and why they happened,  including passing around the actual failed parts for inspection. In nearly every  incident covered it was operator error that caused the failure. It was  quite a history lesson and a shame that all the naysayers here couldn't have  listened to the lecture and educate themselves. 

  

 As far as the refinements that have been done to the Jabiru line of  engines, the hydraulic lifters were developed to reduce maintenance, primarily  for flight schools who use aircraft with the Jabiru engine. IOW, eliminating the  need to adjust the valves every 50 hours as with the solid lifter version. I  seem to recall them saying that overall, parts were removed, not added to  achieve this enhancement. Not sure what you mean by cam followers. They're in my  engine and every other one of the half dozen or so engines I saw disassembled  during the Jabiru course. Perhaps the early Jabiru engines didn't have cam  followers? 



Similarly, I'm not sure how you can look at the innards of a  Rotax 912 and the way the crank is supported, then compare it to a Jabiru and  say the Jabiru is "lightly built". Have you ever seen a 3300 with the case  split? There are seven (7) crank support bearings in the Jabiru, one on  each end, and one between each connecting rod. The Jabiru is built like a  tank compared to the 912/914, or more appropriately, built like a Lycoming,  Franklin or Continental. Compare that to the three crank support bearings in the  Rotax 912/914, coupled to high compression pistons and an engine that isn't all  that well balanced and ????. This weak support of the crank is directly  related to the high number of crank and case failures that have happened  with the 912/914. Rotax also had a bad run of cranks out for a while about 10  years ago. One guy who used to keep a 914 powered Katana motorglider at my  field had one.

 

The crank/flywheel dowels were a response to reported failures in the  flywheel attachment bolts on a limited number of aircraft. To my knowledge, none  of the flywheel bolt failures caused any accidents or forced landings, but  rather were found during routine inspection. This flywheel bolt issue later  turned out to be limited to engines that had sustained unreported prop strikes.  I was told at the Jabiru seminar that there have been no reported failures of  the flywheel bolts on any engines except those that had sustained prop strikes,  but the dowel pins were a good idea, especially if you are going to run a heavy,  unapproved prop, like an MT.  So, they were added to new engines and to  engines that are sent back to the factory for overhaul. Makes perfect sense to  me and certainly doesn't overly complicate the engine at all.



The Jabiru  3300 is one of the simplest four stroke engines I've ever seen. I've handled  every part in a 3300 and assembled one piece by piece from the case up. I don't  know how you could make a four stroke engine any simpler. Simple is a good thing  when it comes to an aircraft engine, IMHO. Everything about the 3300 is well  thought out and made as simple as is humanly possible. The machining is top  notch. Both the 2200 and 3300 continue to be refined to this day as the fleet  hours increase and maintenance issues reveal themselves, just like Rotax  engines.  The 912, by comparison, is off the scale in terms of  complexity, IMO. All that stuff is just more that can go wrong. 

   	  Quote: 	
		  >>>>>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 ?<<<<<

	


 

Depends on the car manufacturer. A Ford, Toyota, or Honda? Very  reliable. A Fiat, Yugo, or GM? Not so much.

 



   	  Quote: 	
		  >>>>>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).<<<<<<

	


 

Yep, and the fleet hours of the Jabiru 2200/3300 continue to climb with  every passing day, but you must also realize that Rotax has a 10-12 year head  start on Jabiru. Give 'em some time. They're working as fast as they can to  replace Rotax as the engine of choice in sport aviation. There are now several  thousand of these engines flying world wide in a wide range of aircraft, both  certified and noncertified. Jabiru will continue to sell this fine little engine  in large numbers because it works well, it's simple, powerful and the engine and  the basic replaceable parts, as well as major engine components, are  considerably cheaper than Rotax engines and parts. This was one of the design  goals of Jabiru, build an engine with as many common parts as possible to keep  the initial purchase price and maintenance costs down. I believe they have  succeeded. Initially, Jabiru's original intent was to only build engines  for their own line of aircraft, but outside demand for the engine became  overwhelming and they have been selling engines outright for use in non-Jabiru  airframes.

 	  Quote: 	
		  >>>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.<<<<<



 

Yes, I've been to Europe many times and I'm aware of the restrictions  placed on you by your nanny state governments. My Jabiru 3300, at take off  power, was measured at 71 dB from 100 yards off the runway. My neighbor's  Husqvarna lawn mower measured minutes later at a distance of 230 yards was  measured at 89 dB. My Ximango 912S spinning a Hoffman prop was measured later  that same day using the same dB meter under nearly identical conditions at take  off power at 75 dB at 100 yards. I don't know what Jabiru's you are listening  to, perhaps one with straight pipes and no muffler? Mine is very quiet, yet the  noise it does make is a deep, throaty sound similar to a Beechcraft. I much  prefer a low, throaty sound to the high pitched Rotax whine. Prop noise isn't a  problem, either, when the engine is tuned for the airframe. At take off load you  should only see 2800-2900 RPM. When I hear an airplane go over I can tell  instantly from inside the hangar with the doors closed if it has a Rotax or not.  The Rotax whine is piercing to my ears.



Oh, and regarding radial engines,  you know they aren't really a portable oil leak, they just like to mark their  territory.....

  

 Regards,

  

 John Lawton

 Whitwell, TN (TN89)

N245E - Flying



  [quote][b]

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Gilles.Thesee(at)ac-greno
Guest

Posted: Wed Jan 27, 2010 1:01 pm Post subject: Jabiru engines.

Hi John,



 	  Quote: 	
		   It might behoove you to take a look at the Rotax Service Instruction 

 on the 912 that came out last March (2009) regarding oil changes. 

 Specifically, SI-912-10R3 dated March 19, 2009. This SI runs 

 concurrent with SI 912-018 entitled "Purging of Lubrication System" In 

 SI 912-018, it specifically describes how to purge the oil system when 

 changing the oil in a 912/914 to remove old oil and then how to 

 rebleed the system with new oil. Doing this procedures ensures that 

 the journals, bearings, rocker arms, etc are all properly lubricated 

 prior to start up after the oil change. SI 912-010 R3 reiterates this 

 method because so many Rotax 912/914 owners have not been following 

 the proper oil change procedure and bearing failures, among other 

 things, have resulted. Kerry down at Lockwood in Florida told me that 

 if you aren't doing this procedure "you are asking for 

 trouble".  There is a similar SI issued for the 914 with the same 

 date. Some people refer to this procedure as "burping the engine" 

 because of the noise it makes when you are purging.


	


There is some confusion, here. "Burping" the engine is turning it by 

hand to ensure all oil is back into the tank before checking the oil 

level. I'm used to doing that -albeit for other reasons- on any engine 

that has not run for some period of time.

Purging the circuit is something else : it is what is called "preoiling" 

by some other manufacturers. One should do that on ANY engine after 

draining the internal oil circuit or reassembly.

The hydraulic lifters are not a panacea, and they are very susceptible 

to air pockets on start. The Jabiru lifters are no exception. I'll 

suggest you preoil -or purge- your oil circuit any time you remove 

significant parts of your engine, whatever the brand.



 	  Quote: 	
		   You can simply drain the oil from the tank, change the filter and 

 refill with new oil, but you are leaving nearly a quart of old oil in 

 the engine and lines if you do it that way. I'm not that familiar with 

 the 912/914 configuration as it exists in the Europa, but that is 

 nearly 1/3rd of the oil in my Ximango 912S oil system. Leaving 1/3rd 

 of tht old oil in the lines and engine kind of defeats the purpose of 

 doing an oil change, doesn't it?

Every owner is entitled to do something else than what the SBs, SIs and 
	


manuals say if he wants so. But I would suggest you just operate the 

engine as per the book unless you have access to a considerable engine 

knowledge based on hands-on experience and thorough measurements.

As for myself, I do run and maintain Rotax engines per the manuals and 

manufacturer's instructions with very good results.

 	  Quote: 	
		    

 >>>>>Any serious engine manufacturer SHOULD issue dozens of SBs, SLs, 

 etc...<<<<<



 The Jabiru engine continues to be refined, just like the Rotax 912/914 

 and it has proven to be at least as reliable as the Rotax, if not more 

 so because it is so simple, but, as with any aircraft engine you have 

 to tune it for your airframe for best results.

There are too few Jabiru engines in my country as compared to Rotax to 
	


support any valid comparison.



 	  Quote: 	
		   The Jabiru is built like a tank compared to the 912/914

That's your opinion, sir, and you are entitled to it.
	




 	  Quote: 	
		   , or more appropriately, built like a Lycoming, Franklin or 

 Continental. Compare that to the three crank support bearings in the 

 Rotax 912/914, coupled to high compression pistons and an engine that 

 isn't all that well balanced and ????. This weak support of the 

 crank is directly related to the high number of crank and 

 case failures that have happened with the 912/914. Rotax also had a 

 bad run of cranks out for a while about 10 years ago. One guy who used 

 to keep a 914 powered Katana motorglider at my field had one.

That's one failure, sir.
	


The spate of broken crankshafts you are referring to is unheard of in my 

area.

I won't enter any Rotax vs Jabiru dispute based on "crankshaft better 

support" or "built like a tank" arguments, because what makes engines 

last is engineering, not opinions.



What counts is you're happy with your engine.

As for myself, I always do everything I can to learn more on any engine 

before expressing an opinion. Especially when a "high number ...of 

failures" is referred to.



Best regards,

-- 

Gilles

http://contrails.free.fr

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