That is GREAT NEWS... As a CFI-ME and a freight dog in PA-34-220T Seneca III w/ factory known-icing (FIKI) package, "full de-ice": boots, hot plate on windshield, heated props. I have a lot of time in make/model, some scary. I used the FIKI equip, flying over the Cascades middle of night. I was young never do that again. With that said DH is going to need more ponies than 180HP and the bigger engines, which are still in approval phase. Are they even in mass production of DHK180 yet?
"DeltaHawk produces the FAA-certified 180 HP DHK180 and is releasing 200 HP (DHK200) and 235 HP (DHK235) models in 2025-2026." I assume the DHK235 would be the ticket for the Seneca. Hope they get it on line soon.
"DeltaHawk is developing a 350-horsepower jet-fueled engine, the DHK6A350, a six-cylinder variant intended for high-performance aircraft with expected FAA certification in 2027. This engine is set to power the Bushliner 1850, currently." Hope they make their schedule, but they need to DHK180 into full production first. On other hand need orders to ramp up; bad business to make engines without buyers lined up.
Seneca III and IV and V uses two turbocharged
Continental TSIO-360-KB engines, 220 HP. unsung hero engine, very Continental smooth, powerful, reliable. Back in the day people tried or at least waxed poetic about putting them in RV's. I know of one for sure. but it never took off in RV's (see what I did there, pun intended).
The Seneca V current model is in low production, not publish but in the dozens range not 100's.
If Piper/DH can deliver, keep price below the TSIO-360-KB powered Seneca V, produces same power, it could be a hit, a Diamond DA62 (1.5M-$1.8M) killer? I see the biggest selling point of diesel/Jet-A reciprocating engines (besides my VW TDI diesel, heavy equip, large ships, trains, 18-wheelers, generators) is flying in parts of the World where 100LL Av Gas is not available, but diesel is available.