There has been a bit of discussion on this topic in other forums. I have to admit that the concept of re-engining piston aircraft and helicopters is extremely interesting, very practical and is definitely going to happen.
Apart from the amazing simplicity and reliability of the engine, the ability to build a product to known weight, performance and dimensional requirements to slot into existing products is a very practical business concept. The fact it uses a fuel that is now more common than Avgas at most airports, is just another benefit!
There has been some quite reasonable rumours regarding a helicopter manufacturer designing their first piston product in about 40 years, as the cost of turbine engines is so exorbidant. Whilst the reliability of piston engines has increased dramatically (er...maybe excepting Continental crankshafts) the reliability of small turbines has remained about the same - only the cost of owning and operating them has gone through the roof. A diesel engine in a small helicopter would be a very strong selling point.
I think this is an excellent programme and will lead one of the greatest technological aviation advancements of the next decade.
Former PPRuNe thread, with links to all the major manufacturers programmes:
http://www.pprune.org/ubb/NonCGI/For...ML/000280.html
Any ideas how this guy intends to certify this TD? Experimental category, or is he going to be the STC fleet leader?