sandpiper Posted January 16, 2017 Report Share Posted January 16, 2017 I have not owned a Cont 550 like gbigs does although I have flown a few. However, one of the engines I owned the longest was the IO-520 in my U-206. I took it from 500 hours to 1700 hours (TBO) at which time I sold the plane. During this journey it needed 2 or 3 new/replaced/rebuilt cylinders. Valve guides I think. Since I flew several different planes during this time, mine was lucky to see 75 hours/yr which doesn't do much for longevity. Also, like most planes where I lived they were not hangared and winter temperatures are extreme. Until the CT, most of my planes I owned over 43 years had Cont. engines. There was always a lot of anxiety on my part around annual time until I got the word on the cylinders. It has been my experience, and that of others I have known, that privately owned low usage Continentals will not make TBO without some cylinder work. Maybe gbigs will be the exception? Link to comment Share on other sites More sharing options...
Tom Baker Posted January 16, 2017 Report Share Posted January 16, 2017 When I started out my young mechanics career I worked on quite a few Beechcraft Barons that were flown for charter or corporate use. These airplanes were flying 2-300 hours a year. The engines were always replaced with factory remanufactured when it was time. It was not uncommon when you reached the 1,000 hour mark to have cylinders to be worked on. One thing that has helped Continental since then is the development of a service bulletin that allows for compression readings with leakage past the rings that are way below what for years was considered to be the industry lower limit. In addition to the compression test you also have to bore scope the inside of the cylinder, looking for signs of corrosion and burnt valve Link to comment Share on other sites More sharing options...
Buckaroo Posted January 16, 2017 Author Report Share Posted January 16, 2017 Do cont and lyc coat with nikasil? Link to comment Share on other sites More sharing options...
Tom Baker Posted January 16, 2017 Report Share Posted January 16, 2017 Do cont and lyc coat with nikasil? I don't think so, but some of the aftermarket cylinder suppliers do. Link to comment Share on other sites More sharing options...
gbigs Posted January 16, 2017 Report Share Posted January 16, 2017 "a few hundred Rotax engines" How many. 50K engines with 5 million run hours and BRP / Rotax has been making engines since the 1920's and the 912 since late 1989. They supply 80-85% of the world's small aircraft engines. "A majority of engines (including Rotax) do not reach TBO." Actually this isn't true. Most Rotax do reach TBO "Does the CT have a mixture control?" It doesn't need it. just like most motorcycles without fuel injection. I found no stats that support "most Rotax reach TBO". Are you also saying CHT temps are constant and never go yellow or red in a CT? I found this study publised a couple of months ago, here is an excerpt: Aircraft powered by Jabiru engines were involved in the most engine failures or malfunctions with 130 reported over the 6 years. Reports from Rotax powered aircraft were the next most common with 87 (one in 36), followed by aircraft with Lycoming (58 – one in 35) and Continental (28 – one in 35) engines. https://www.atsb.gov.au/newsroom/news-items/2016/light-aeroplane-failures/ Link to comment Share on other sites More sharing options...
Roger Lee Posted January 16, 2017 Report Share Posted January 16, 2017 It's in print from the Rotax Mfg and on the web. They just posted all this a year or so ago during their anniversary. Link to comment Share on other sites More sharing options...
sandpiper Posted January 17, 2017 Report Share Posted January 17, 2017 I found no stats that support "most Rotax reach TBO". Are you also saying CHT temps are constant and never go yellow or red in a CT? I found this study publised a couple of months ago, here is an excerpt: Aircraft powered by Jabiru engines were involved in the most engine failures or malfunctions with 130 reported over the 6 years. Reports from Rotax powered aircraft were the next most common with 87 (one in 36), followed by aircraft with Lycoming (58 – one in 35) and Continental (28 – one in 35) engines. https://www.atsb.gov.au/newsroom/news-items/2016/light-aeroplane-failures/ I wonder how many of those Rotax failures were 2 stroke? Link to comment Share on other sites More sharing options...
Roger Lee Posted January 17, 2017 Report Share Posted January 17, 2017 Since 1920, who knows. Link to comment Share on other sites More sharing options...
FredG Posted January 17, 2017 Report Share Posted January 17, 2017 Interesting data. Roger - 1920? The cited study was conducted from 2009 to 2014. The aircraft "population" was limited to a maximum of 800 kg, so pretty light aircraft. John is right, the 2-stroke question is key to interpreting the data. Finally, it would be useful to know what constitutes "failure or malfunction" fg Link to comment Share on other sites More sharing options...
Tom Baker Posted January 17, 2017 Report Share Posted January 17, 2017 Interesting data. Roger - 1920? The cited study was conducted from 2009 to 2014. The aircraft "population" was limited to a maximum of 800 kg, so pretty light aircraft. John is right, the 2-stroke question is key to interpreting the data. Finally, it would be useful to know what constitutes "failure or malfunction" fg I hadn't taken time to look at the report yet, so I took a glance. IMO this report was conducted to prove that Jabiru engines are having a higher failure rate than other engines in use in Australia. If a person has followed the aviation news over the past few years they would know there was a push to ground Jabiru powered aircraft in Australia. One other thing worth noting, the OP of the study is trying to use the study to prove that the failure rate of Rotax engines is greater than the Continental 550 installed in his Cirrus. The data of failure rates was based on aircraft with a take off weight of 800kg or less, because of this the larger Continental engines would not have been covered in the study. Link to comment Share on other sites More sharing options...
FlyingMonkey Posted January 17, 2017 Report Share Posted January 17, 2017 I tried really hard to balance my carbs, but ice cream is just too damned tasty. Link to comment Share on other sites More sharing options...
gbigs Posted January 17, 2017 Report Share Posted January 17, 2017 Interesting data. Roger - 1920? The cited study was conducted from 2009 to 2014. The aircraft "population" was limited to a maximum of 800 kg, so pretty light aircraft. John is right, the 2-stroke question is key to interpreting the data. Finally, it would be useful to know what constitutes "failure or malfunction" fg No mention of 2 versus 4 stroke in the study, but the engines compared included Rotax, Lycoming and Continental. Interesting to note that there were 87 Rotax engine failures to just 28 for the Continentals over that 2009 to 2014 6 year study period. Link to comment Share on other sites More sharing options...
FlyingMonkey Posted January 17, 2017 Report Share Posted January 17, 2017 No mention of 2 versus 4 stroke in the study, but the engines compared included Rotax, Lycoming and Continental. Interesting to note that there were 87 Rotax engine failures to just 28 for the Continentals over that 2009 to 2014 6 year study period. That's not a useful data point unless we know how many of each type are installed in the fleet. I'd bet if we compared just four stroke Rotax to small Lycoming and Continental engines under 125hp or so, the reliability rates would be close. Link to comment Share on other sites More sharing options...
Tom Baker Posted January 17, 2017 Report Share Posted January 17, 2017 No mention of 2 versus 4 stroke in the study, but the engines compared included Rotax, Lycoming and Continental. Interesting to note that there were 87 Rotax engine failures to just 28 for the Continentals over that 2009 to 2014 6 year study period. The take away from the study is that in this weight category of airplane that Rotax out numbers continental by over 3-1. The failure rate per number in operation is just under 3% for both manufactures. Also as I pointed out earlier it doesn't cover all continental engines. The study covers aircraft with a maximum takeoff weight of 800KG (1764) or less. This is going to limit the Continental engines covered by the study to the IO-240 or smaller, with the 0-200 likely being the most common down to the A-65. Link to comment Share on other sites More sharing options...
Tom Baker Posted January 17, 2017 Report Share Posted January 17, 2017 That's not a useful data point unless we know how many of each type are installed in the fleet. I'd bet if we compared just four stroke Rotax to small Lycoming and Continental engines under 125hp or so, the reliability rates would be close. They rates are close without separating models. In fact the Rotax edges out both Lycoming and Continental. Rotax has a failure rate of 1 in 36, compared to Lycoming and Continental that is 1 in 35. The failure rate for all 3 is below 3%. A quick look at the numbers shows that Rotax has more engines operating in this weight class than Lycoming and Continental combined. Link to comment Share on other sites More sharing options...
FlyingMonkey Posted January 17, 2017 Report Share Posted January 17, 2017 I found no stats that support "most Rotax reach TBO". Are you also saying CHT temps are constant and never go yellow or red in a CT? I found this study publised a couple of months ago, here is an excerpt: Aircraft powered by Jabiru engines were involved in the most engine failures or malfunctions with 130 reported over the 6 years. Reports from Rotax powered aircraft were the next most common with 87 (one in 36), followed by aircraft with Lycoming (58 – one in 35) and Continental (28 – one in 35) engines. https://www.atsb.gov.au/newsroom/news-items/2016/light-aeroplane-failures/ If you are talking all Rotax, well yeah, a lot of them are 2 stroke with a 300hr TBO (Rotax 582). Link to comment Share on other sites More sharing options...
Doug Hereford Posted January 18, 2017 Report Share Posted January 18, 2017 I would agree that Continental engines (especially "big" ones) seldom go to TBO without a cylinder or two having unscheduled mx. I have worked on many of these engines that are used in commercial operation (135). They typically need more attention in my opinion. That may be due to poor operational techniques though. I have changed numerous Lycoming cylinders as well, but many of those were subjects of Airworthiness directives, and not any observed failures during scheduled inspections. I worked in an engine overhaul shop in the late 80's. Approx. every 3rd Lycoming cylinder had head cracking either at the sparkplug boss, or between the valve seats. Continental cylinder cracking was much less frequent, but when they were cracked, it was much worse. I do think that a lot of Continental cylinders are changed needlessly, but this may have improved with education and a more common reference to the previously noted SB 03-3. I have never changed a Rotax 912 cylinder. In perspective, the Rotax powered aircraft that I have maintained probably have a combined total of 5000 hrs. TIS. Continental and Lycoming would be in the million hour TIS range. Link to comment Share on other sites More sharing options...
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