Was the Conti IO-360 specially troublesome?
Conti IO engines are great if you are Silvaire, have a hangar, tooling, all the time in the world and a mechanic who helps you for free. If you want something that works along the “kick the tires light the fires” principle, they ain’t it.
Peter wrote:
Was the Conti IO-360 specially troublesome?
I think that is beside the point actually. That is, until you have tried a Rotax 
Seriously, it is hard to explain, but the difference is like Windows 3.1 on top of DOS running on a huge desktop with a CRT display compared with Android 5.1 on a pad/phone They both do the job, but that is about all they have in common.
If you want something that works along the “kick the tires light the fires” principle, they ain’t it.
What happened to yours?
That is, until you have tried a Rotax Seriously, it is hard to explain, but the difference is like Windows 3.1 on top of DOS running on a huge desktop with a CRT display compared with Android 5.1 on a pad/phone They both do the job, but that is about all they have in common.
Can you post a detail comparison?
Other than the fuel flow setting that has been set wrong for idle, nothing yet. But the mere idea that in order to do that an engine manufacturer wants you to use a “PortaTest” (lol) unit which really is a couple gauges and some plumbing (worth only 4’995 and chump change) or go and buy other gauges, together with the amount of lore as opposed to fact as to how the engine should be in fact set up is (to me) a good indication of why incidents happen and how far past its prime the industry really is. At idle I’m sure the engine doesn’t stop on final only because the inertia of the windmilling prop is pulling it through. With a light MT 4 blade I’m not sure it would keep running.
Peter wrote:
Can you post a detail comparison?
No, I can’t. I don’t think anyone can. Firstly 99% of all Rotax 91X are not certified. They are “experimental” and so they are maintained in a different fashion. Second, there are close to no maintenance needed. Change oil and sparkplugs at regular intervals, and off it goes. Third, you just push the “start” button, and it starts and runs until you want it to stop. It is not an engine in the Lycoming/Continental sense, it is a compact and unbreakable “Swiss machinery” power package with a propeller up front. A plug ’n play device. Broadly speaking of course
Peter, the IO-360 Continental isn’t as the greatest engine in the world. My observation is that Continental has generally followed a less rational approach to engine development than Lycoming, going off in different directions in a slightly random fashion, one of which was making a small six cylinder engine when a four cylinder would be better. Continental’s peak design period was pre-war and early post-war, up until Lycoming got going, but I think the little 100 HP and less Continentals are still a pretty good engine that I would prefer to own over a Rotax.
As for the Rotax being “modern” I think it’s modern in some good ways (good cylinder design), modern in some bad ways (throw away design philosophy, twin Bing carbs) and very old fashioned in its impractical and over complex crankshaft design. The closest aircraft engine crankshaft design I can think of is the pre-war Hirth engines as used on Bückers and the like. Those types of engines, along with stuff like DeHavilland, Tigres, Walter Mikrons were all largely put to bed in the 50s by the Lycomings for good reason – they required lots of fiddling and were complex to overhaul. Some built-up motorcycle crankshafts remained until roughly the early 80’s, but then they transitioned to automotive/aircraft practice.
As an aside, Rotax engines used on motorcycles (Aprilia, BMW, Buell etc) are similar when compared to their European and U.S. competitors, and actually more like Japanese motorcycle engines. I don’t particularly like Rotax for that application either. I’d certainty ride one as a rental bike or whatever (in fact I have done so) but I wouldn’t buy one. It’s exactly the same situation.
Does the “impractical and complex crankshaft design” impact ease of operation or require extra maintenance?
With modern labor rates and the scarcity of skilled labor, a built up crankshaft assembly is a throw away item, including the connecting rods, every time you overhaul the engine. That’s expensive and dumb. The world finished moving away from that design, for those reasons plus the lack of structural stiffness, in the 1980s. Once reliable oil pumps and oil filtration were available in about 1935, plain bearings became the best solution and they don’t require a crankshaft pressed together and aligned by hand.
Maybe it doesn’t matter, for the private aircraft owner market, because almost nobody reaches TBO on a specific engine during their flying lifetime.
And if somebody is doing say 200hrs/year (which is only a tiny % of even “touring” pilots) they will be spending so much money on fuel etc etc (probably c. €30k/year) that throwing the engine away after 10 years doesn’t matter.
A certain (small) % of Cirrus owners buy a brand new plane, with all the latest gear, every couple of years or every time an upgraded model comes out. They aren’t worried about money either. There is a lot more of them in the car market.
