Read the link. The 4-cyl is 300# and makes either 350 or 500 hp. For my Cessna 180? That would offer a significant power increase with a weight reduction.
It's not flying yet. I wonder if there's a prototype running. If they can achieve their claimed numbers, it will be an awesome engine, though it is still a spark-ignited engine. One of the attractions of diesel is its compression ignition. No sparkplugs or other ignition stuff other than the glow plugs for starting.
The certified SMA SR305-230E is STC'd for the Cessna 182P and Q. It's heavy. The numbers:
455 pounds. The O-470U it replaces is 412 pounds. The battery had to be relocated from the firewall to the tailcone to balance it and the intercooler and massive oil cooler (cylinder heads are air- and oil-cooled) and to make room for those big coolers.
It generates its 227 HP at 2200 RPM, redline, and the prop governor is set to that RPM and never moves. It uses a more-efficient composite prop that loses less HP to drag at that low RPM. Full FADEC with mechanical override in case of computer failure. But it has disadvantages, too, like the allowable starting temperature range of -5°C (23F) to 45°C (113°F). That won't work for a lot of folks, especially the low temp limit.
We did a bunch of work on one of the first generation installations, replacing some cracked bracketry and repairing leaks. They had teething problems early on. When it starts, the FADEC will not respond to throttle inputs until it reaches a certain minimum engine temperature, and it idles at maybe 700 RPM. Its four big cylinders and 15:1 compression ratio makes it vibrate a lot at that speed, and it cracks stuff. I found one prop blade cracked, probably from the vibration. A metal prop would have made that engine move even more.
It's an expensive conversion. $80K+ last I heard.
