Narrabeenrick Posted January 31, 2017 Share Posted January 31, 2017 Hi guys . I’m looking at building the Zenith CH 650 and looking at engine choices, the 2 engines I have flown using like most are the Jab’ and the rotax. In all the forums I always see people knocking the jab’ motors and raving about the rotax. I’m am only new to this game so I’m trying to keep an open mind and rely on fact and figures not here say and or bias opinions. I can be swayed either way. I have just been on the Ra Aus site looking at the “ Accident and defect summaries” page I only got through the first 3 pages of engine “loss of power “ and “ failures “ here is what the stats tell me so far Rotax engine “loss of power “ and “ failures “ 28/01/17 26/01/17 6/01/17 28/12/16 28/12/16 23/12/16 8/12/16 18/11/16 18/11/16 Jabiru 31/12/16 That like I said first 3 pages !!!!!!!!!!!!!!!! I know which way I’m leaning . Any thoughts? Cheers Rick 1 Link to comment Share on other sites More sharing options...
Downunder Posted January 31, 2017 Share Posted January 31, 2017 OK, I guess It's me firing the first shot...... Long term, you are better off with a Rotax. And when people talk about purchase prices, I say it is cheaper to finance the difference via a loan if required. The interest on a loan potentially outweighs ( is better than) the extra money spent on the maintenance of a Jabiru.... 1 Link to comment Share on other sites More sharing options...
fly_tornado Posted January 31, 2017 Share Posted January 31, 2017 properly maintained, there is nothing stopping a Rotax as being as reliable as a Jabiru 5 1 Link to comment Share on other sites More sharing options...
planesmaker Posted January 31, 2017 Share Posted January 31, 2017 Unbiased thoughts from the internet? If I gave you my opinion it would definitely be biased. Link to comment Share on other sites More sharing options...
rgmwa Posted January 31, 2017 Share Posted January 31, 2017 Might as well toss a coin. It will be quicker and just as reliable. rgmwa 2 1 Link to comment Share on other sites More sharing options...
KRviator Posted January 31, 2017 Share Posted January 31, 2017 But why did those Rotax's fail? And what was the total hours flown in that period vs the Jabiru engine? Eg, it there were 9 Rotax failures, and rotax's flew 9,000 hours, vs just 1 jab failure, but the total jab fleet flew 500 hours, the Rotax's are still twice as reliable as a Jab. Without knowing figures like these, it is impossible to make an informed decision. That being said, unfortunately Jabiru engines have a stigma associated with them know, whether deserved or not, so everything else being equal, resale is likely to be significantly better with a Rotax, but again, that is only part of the story. What about performance figures between the two? Overhaul intervals based on fuel anticipated fuel usage? 1 Link to comment Share on other sites More sharing options...
SDQDI Posted January 31, 2017 Share Posted January 31, 2017 The new jabs have hardly done enough hours to prove their reliability on a broad scale yet so they could be good but they are not a 'known'. Rotax's haven't changed (unless you are looking at an 912 is or a 915) so there are reliable stats out there. Your chances of getting to tbo with a rotax without big costs are pretty good but they require a fair bit of extra upfront cost. Basically my thinking would be if you can afford the original outlay go the rotax, but if funds are limited then the jab would be the go keeping in mind that 'some' have had to spend quite a bit of money on them before the placarded tbo. If going the jab then extra care would be needed to sort the cooling side of things whereas the rotax will be a lot more forgiving. 1 Link to comment Share on other sites More sharing options...
Admin Posted January 31, 2017 Share Posted January 31, 2017 Firstly let me say that we don't allow any unwarranted digs against any engine on this site, the posts just get deleted. It can just come down to a Holden vs Ford thing and eveyone has different opinions of what they just simply prefer Some things I would be thinking about are: 1. Which engine fits/works better in the airframe you have chosen 2. What about CofG of the aircraft with the different weights of each engine 3. What horsepower do you need 4. What type of flying will you be mostly doing 5. How easy is access of the different fuels 6. What resources do you have at the airfield i.e. other aviators, lame etc that you have access to to discuss any issue you may come across These are just some of the questions I would be thinking of to answer the question. The above may not be of any use but just in case it does help 1 3 Link to comment Share on other sites More sharing options...
Narrabeenrick Posted January 31, 2017 Author Share Posted January 31, 2017 But why did those Rotax's fail? And what was the total hours flown in that period vs the Jabiru engine? Eg, it there were 9 Rotax failures, and rotax's flew 9,000 hours, vs just 1 jab failure, but the total jab fleet flew 500 hours, the Rotax's are still twice as reliable as a Jab.Without knowing figures like these, it is impossible to make an informed decision. That being said, unfortunately Jabiru engines have a stigma associated with them know, whether deserved or not, so everything else being equal, resale is likely to be significantly better with a Rotax, but again, that is only part of the story. What about performance figures between the two? Overhaul intervals based on fuel anticipated fuel usage? Thanks for your reply , just wondering if your can put on the page where you got the 9,000hrs vs 500hrs , I'd love to read that article if you don't mind. Cheers 1 Link to comment Share on other sites More sharing options...
Camel Posted January 31, 2017 Share Posted January 31, 2017 I'm an air cooled engine man and prefer direct drive also BUT when using an engine in a Stol aircraft I think your are better off with water cooled and reduction as it suit slow flight. The Jabiru would require a finer prop for short field to develope its full horse power, where a Rotax can develope a lot of power because of a reduction box. Cooling is an issue if your going to climb steep and slow. 1 1 Link to comment Share on other sites More sharing options...
Narrabeenrick Posted January 31, 2017 Author Share Posted January 31, 2017 Firstly let me say that we don't allow any unwarranted digs against any engine on this site, the posts just get deleted. It can just come down to a Holden vs Ford thing and eveyone has different opinions of what they just simply preferSome things I would be thinking about are: 1. Which engine fits/works better in the airframe you have chosen 2. What about CofG of the aircraft with the different weights of each engine 3. What horsepower do you need 4. What type of flying will you be mostly doing 5. How easy is access of the different fuels 6. What resources do you have at the airfield i.e. other aviators, lame etc that you have access to to discuss any issue you may come across These are just some of the questions I would be thinking of to answer the question. The above may not be of any use but just in case it does help Yeah thanks for your reply. They give you a choice of Jabiru 3300 Continental O-200 Corvair Lycoming Rotax CofG not sure They recommend 100hp to 130hp I plan on touring MOGAS (95 RON) and lastly not sure . Like I said I'm open to either as well as the UL power ! and thoughts on that engine as well ? Cheers Rick Link to comment Share on other sites More sharing options...
Narrabeenrick Posted January 31, 2017 Author Share Posted January 31, 2017 I'm an air cooled engine man and prefer direct drive also BUT when using an engine in a Stol aircraft I think your are better off with water cooled and reduction as it suit slow flight. The Jabiru would require a finer prop for short field to develope its full horse power, where a Rotax an developed a lot of power because of a reduction box.Cooling is an issue if your going to climb steep and slow. The CH 650 isn't the STOL , that is the 701 /750. check out the 650 and see what you think . Love to hear back from you . Cheers Link to comment Share on other sites More sharing options...
KRviator Posted January 31, 2017 Share Posted January 31, 2017 Thanks for your reply , just wondering if your can put on the page where you got the 9,000hrs vs 500hrs , I'd love to read that article if you don't mind. Cheers Those figures didn't come from any article, they were used as an example that you cannot rely on simple "x number of failures in a calendar period" as a means of proving, or disproving, reliability. You need to compare apples with apples, ie MTBF as a number of flight hours across the fleet, and without those numbers, any statistics showing Engine A is more reliable than Engine B is both meaningless and misleading. Link to comment Share on other sites More sharing options...
Narrabeenrick Posted January 31, 2017 Author Share Posted January 31, 2017 Those figures didn't come from any article, they were used as an example that you cannot rely on simple "x number of failures in a calendar period" as a means of proving, or disproving, reliability. You need to compare apples with apples, ie MTBF as a number of flight hours across the fleet, and without those numbers, any statistics showing Engine A is more reliable than Engine B is both meaningless and misleading. AH ! so you didn't read the bit in my initial bit ? this bit "I’m trying to keep an open mind and rely on fact and figures not here say and or bias opinions" ! Link to comment Share on other sites More sharing options...
Narrabeenrick Posted January 31, 2017 Author Share Posted January 31, 2017 Just reading another article from ATSB that says “Aircraft powered by Jabiru engines were involved in the most engine failures or malfunctions with 130 reported over the 6 years. Unlike the engines of other engine manufacturers in this study, nearly half of the Jabiru engine failures or malfunctions related to a fractured component. Engine through-bolt failures were the most commonly reported failure mechanism in Jabiru powered aircraft with 21 through-bolt fractures reported between 2009 and 2014” So my next question is if they have replaced the bolts with larger, stronger bolts , then you would assume that if half of jab engine failures they bolt then that should stop half the engine failure ? To simplistic ? Link to comment Share on other sites More sharing options...
KRviator Posted January 31, 2017 Share Posted January 31, 2017 AH ! so you didn't read the bit in my initial bit ? this bit "I’m trying to keep an open mind and rely on fact and figures not here say and or bias opinions" ! No no, I did read exactly that, and I also read that you appear to be "leaning" towards the Jab based on it having fewer reported incidents in 3 pages of accident reports than the Rotax - but you also didn't specify your search term, if you simply plugged "Rotax" and "Jabiru" into the search box, then your comparisons are even more meaningless than simply saying "there was only one Jab engine failure compared to 9 Rotax failures". You will get failures of 503's, 582's, 618's, 914's and the gamut of 912-series. Which ones do you want? Did you break down the failures of 912's into UL, ULS, the early models, etc...The point I am trying to make is, without knowing why they failed (you can't really blame a SkyGod running out of fuel on the engine), and how many hours were flown across the fleet by aircraft fitted with the engines you are comparing against each other, then your investigation will give a flawed result, no matter your best intentions. If you want the most reliable engine you can put in an RAAus aircraft, it is a Lycoming. Why? Because there have been no, that's right, zero, reported failures of lycoming-powered RAAus aircraft to my knowledge. But there are probably only 6 RAAus aircraft actually powered by a Lycoming that might fly a combined total of 300hours a year versus 10 Rotax failures in 10,000 hours. See where I'm coming from? 1 1 2 Link to comment Share on other sites More sharing options...
SSCBD Posted January 31, 2017 Share Posted January 31, 2017 Why are we not we running manual cowl flap for engine airflow cooling?? Its simple old tech or is it another thing for pilots to push and stuff up? 1 1 Link to comment Share on other sites More sharing options...
ben87r Posted January 31, 2017 Share Posted January 31, 2017 Why are we not we running manual cowl flap for engine airflow cooling?? Its simple old tech or is it another thing for pilots to push and stuff up? Not enough airspeed generally? I was of the understanding that cowl flaps were more to limit over cooling and cooling drag in higher speed flight than allow more at low speeds. 1 Link to comment Share on other sites More sharing options...
SSCBD Posted January 31, 2017 Share Posted January 31, 2017 Not enough airspeed generally?I was of the understanding that cowl flaps were more to limit over cooling and cooling drag in higher speed flight than allow more at low speeds. In airplanes built for cross-country speed, this cooling drag is minimized by keeping the rear cowling opening just big enough for adequate airflow in cruise. At lower airspeeds, like takeoff and climb, the pressure differential created by the opening alone may not be enough for sufficient cooling. For cooling during these high-power/low-airspeed phases of flight, cowl flaps (controllable openings that provide a greater airflow deflection and therefore greater pressure differential) 1 1 Link to comment Share on other sites More sharing options...
Blueadventures Posted January 31, 2017 Share Posted January 31, 2017 Yeah thanks for your reply.They give you a choice of Jabiru 3300 Continental O-200 Corvair Lycoming Rotax CofG not sure They recommend 100hp to 130hp I plan on touring MOGAS (95 RON) and lastly not sure . Like I said I'm open to either as well as the UL power ! and thoughts on that engine as well ? Cheers Rick Hi Checkup about Jabiru engine fuel grade as I recall they need Avgas. I may be wrong. So may not meet your 95 requirements. Link to comment Share on other sites More sharing options...
frank marriott Posted January 31, 2017 Share Posted January 31, 2017 Hi Checkup about Jabiru engine fuel grade as I recall they need Avgas. I may be wrong. So may not meet your 95 requirements. No. Avgas OR Mogas min 95RON as per POH. Personally I use Avgas for better quality control and availability at airports but many use mogas quite happily. 2 2 1 Link to comment Share on other sites More sharing options...
jetjr Posted January 31, 2017 Share Posted January 31, 2017 Much of the comments around regarding Jabiru are now negated. The engine this refers to is largely gone, even Camit versions are now unavailable They have just begun building the first of a newer design with significant changes which may or may not prove successful. Very rocky road with new suppliers and in house engineering being done. Essentially ignore much of the whole Jabiru saga as this is a major redesign and will require a while before any claims can be made on reliability. On paper it looks good. however delivery of significant engine upgrades hasnt gone too well in Jabiru's history. Rotax,912 is an exceptional engine and if it suits the aircraft and you can handle the eye watering cost of purchase and repairs is a great choice. 1 1 Link to comment Share on other sites More sharing options...
facthunter Posted January 31, 2017 Share Posted January 31, 2017 If you are seriously going to do a lot of x country work I would go Continental 0-200 if you can get a good one Perhaps something out of a dead Skycatcher Cessna 162 with 0-200 D. Plenty of those Zenith planes fitted with them. Are you flying VH or RAAus? Nev 1 1 Link to comment Share on other sites More sharing options...
Narrabeenrick Posted January 31, 2017 Author Share Posted January 31, 2017 No no, I did read exactly that, and I also read that you appear to be "leaning" towards the Jab based on it having fewer reported incidents in 3 pages of accident reports than the Rotax - but you also didn't specify your search term, if you simply plugged "Rotax" and "Jabiru" into the search box, then your comparisons are even more meaningless than simply saying "there was only one Jab engine failure compared to 9 Rotax failures". You will get failures of 503's, 582's, 618's, 914's and the gamut of 912-series. Which ones do you want? Did you break down the failures of 912's into UL, ULS, the early models, etc...The point I am trying to make is, without knowing why they failed (you can't really blame a SkyGod running out of fuel on the engine), and how many hours were flown across the fleet by aircraft fitted with the engines you are comparing against each other, then your investigation will give a flawed result, no matter your best intentions. If you want the most reliable engine you can put in an RAAus aircraft, it is a Lycoming. Why? Because there have been no, that's right, zero, reported failures of lycoming-powered RAAus aircraft to my knowledge. But there are probably only 6 RAAus aircraft actually powered by a Lycoming that might fly a combined total of 300hours a year versus 10 Rotax failures in 10,000 hours. See where I'm coming from? Thanks mate for your input. Cheers Link to comment Share on other sites More sharing options...
Narrabeenrick Posted January 31, 2017 Author Share Posted January 31, 2017 If you are seriously going to do a lot of x country work I would go Continental 0-200 if you can get a good one Perhaps something out of a dead Skycatcher Cessna 162 with 0-200 D. Plenty of those Zenith planes fitted with them. Are you flying VH or RAAus? Nev Ra Aus Link to comment Share on other sites More sharing options...
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