If my experiences traveling with a DA40NG are any indicator, having a diesel in the US would be a disadvantage for going places that I’d be interested in going with a light airplane. The range was the same as the gas version and at small airports 100LL is often the only fuel available.
Almost No one - as in a tiny fraction of buyers - buys a brand new engine unless they are buying a brand new airplane. Deltahawk's target market has got to be military or new aircraft.
I'm not sure the source and details on that price. But it's not surprising to me. Prices have gone up since I bought a brand-new YIO-390 for $35,000. The Y in YIO means that the engine cannot be installed on a type certified aircraft and I'm sure it costs a good bit more to get an engine without the Y. So, between inflation and certification, I can see an engine in the 200-300 hp range selling for $86,000.
I suspect the driving force behind the continued development of this engine is something outside of the light airplane market.
I put down a deposit yesterday. https://www.pilotsofamerica.com/com...a-tampico-tb9-i-just-paid-the-deposit.142950/ It is the engine, engine mount, and CS propeller for sure. It MIGHT include a new cowling. I'm still trying to figure that out. They ship it to you, so no installation. I missed it but back in 2019 when they were running free install at their Wisconsin facility as part of the deal. Also, they have been supplying them to the US military for the last decade or two for use in UAS (Drones). That is part of why they have been late to the GA market. That and Covid slowed them down at the end. Up side is that they have lots of data from the drone work to help work out bugs in the design.
The engine can run on Jet A, JP5, JP8, D1, and D2, plus more I'm sure. I believe it is CERTIFIED on all of those. Jet A is generally cheaper on airport than 100LL. Off road diesel (Red dyed D1 or D2) is WAY cheaper.