Antonio wrote:
Like all statistics, we are talking weighed dice here. A couple of examples:
@Antonio, it does not specify if those are 2-stroke or 4-stroke Rotax engines either, and there is a BIG difference. Of if it was a certified Rotax etc.
You are right, there is no point in measuring the average patient temperature across the whole hospital. :)
We fly several Rotax’es in the flight school and never had a dramatic issue. Is this representative? Don’t know. I’d trust my life to a Rotax as I do with my Lyco.
I’d trust my life to a Rotax as I do with my Lyco.
I’d fly both, but trusting them with my life as in „no other option“… never. In a twin it’s another story, but piston engines fail far too often for my liking.
Snoopy wrote:
piston engines fail far too often for my liking
As far as I am concerned a single in flight total engine failure is one too many, but does that approach alone help to improve the situation?
Paul’s take on this, from the same video is this:
How is that related to engine make or even piston vs turbine?
As usual, the answer is a bit less evident than we would like…but we don’t need to think a lot to figure it out!
Antonio wrote:
Overall low power engines (around 100hp) are highly represented by Contis in Cessna 150/152’
A moot point in reality, but the Continental O-200 is present only in the 150, of which relatively few remain; the 152 had a Lycoming O-235.
Could it be that the relative count of Rotax vs. Continental/Lycoming in the US might be a factor for the failure distribution (easier to rack up a high failure average with not a lot of engines, Rotax isn’t exactly popular in the US).
How is that related to engine make or even piston vs turbine?
Paul‘s video is great, however only a part of it is about piston engine reliability, the overall theme is about why engines quit, which is a different topic.
The Federal Aviation Administration (FAA) was quoted as stating turbine engines have a failure rate of one per 375,000 flight hours, compared to of one every 3,200 flight hours for aircraft piston engines.
Rotax delivers the engine. The installation is done by the aircraft manufacturer. This includes such things as radiators, cables, hoses etc + eventual thermostats and eventual vanes and so on. It’s a whole bunch of stuff. Not all aircraft manufacturers are good at doing that.
Also, all the hoses etc have to be replaced every 5 years. On non certified aircraft, high quality hoses can typically be replaced by cheap and poor quality stuff.
A whole lot more can go wrong, and it has nothing to do with the engine as such. A well maintained good installation will run for ages. A poorly maintained bad installation can, with a little bit of luck, become only as good as a Lycoming 
Rotax delivers the engine. The installation is done by the aircraft manufacturer.
That system was cleverly used by Diamond to avoid the company going bust, when Thielert engines started failing. Diamond walked away from liability, saying they are not responsible for the engine
And Thielert blamed Diamond for the failures, saying the coolant system was badly designed by Diamond I remember talking to one of their reps at some exhibition.
I don’t think anyone here knows the details of the contracts between Diamond and Thielert. Thielert may very well have been responsible for the installation in a certified aircraft. After all that is the normal procedure when installing more complex stuff, and clear lines are drawn where the liability of one part ends, and the other part starts.
Most Rotax engines are non certified, and sold off the shelves. The installation is done according to the Rotax Installation Manual.
