Primarily for general aviation discussion, but other aviation topics are also welcome.
#1847764
It's worth watching! It has the best summary of what's been going on with piston engines in the last few decades that I have seen.

Our club converted a C172R to use a Thielert diesel in 2011. The engine management was a joy. We had two main issues:

- The MTOW of our C172 had been increased by 100 kg with an STC to be the same as a C172S; this was before the conversion. When we converted the engine, the STC became null and void, despite assurances from the engine manufacturer to the contrary. In the end we got to keep 50 kg. Even so, the aircraft became essentially a two seater for touring. As Paul points out in the video, there were no incentives for Cessna to change the airframe to allow another 200 kg or so.
- The inspection interval for the gearbox was very short, but we were again assured that this would be solved "soon". That made it difficult to predict the operating costs.

The company we used for service also did Diamond, so the engine competence was available.

We've since sold that aircraft, but not because the aircraft failed to perform. We needed to downsize the fleet and that was the aircraft that we could sell at a good price.
#1848321
Since he's thousands of miles away, he hasn't seen all the grounded diesel aircraft I've seen. Awaiting replacement radiators, gearboxes and even engines, mostly under warranty. One Robin I know of has had two new engines in less than three years from delivery. Think of all that downtime, let alone the maintenance cost, especially if out of warranty.
#1848618
He makes great points.
Better, safer, cheaper to run engines are available but when there's such an easy way to trigger FUD, you need deep pockets, consistent commitment and longevity to break through the inertia. It served IBM well for many years, they lasted longer than they should have, they're are still a force, but now more benign, they have to demonstrate competence rather than fear-monger difference/non-compliance.
Essentially existing owners (and manufacturers) are the problem, and aggressive anti-marketing.