DeltaHawk Engines is celebrating the July 2 first flight of a Piper Seminole with DeltaHawk’s DKH compression ignition engines on each side. The company said on Facebook that it spent less than a year adapting the popular multi-engine training twin to Jet A power and the first hop was uneventful. The plane is fitted with counterrotating engines and is the test bed for the future Seminole DX. The company said they were “celebrating the freedom from avgas” with the flight and predict the diesel trainer will “revolutionize multi-engine flight training.”
The Seminole DX project was announced at AirVenture 2025 and uses 180-horsepower versions of the scalable DHK design. The plan is for DeltaHawk to get an STC that will allow Piper to incorporate the Jet A (or A1) version into its regular production line. A version certified for sustainable aviation fuel (SAF) is in the works. The companies had hoped for certification this fall and deliveries by the end of the year but that’s obviously going to slip some. Piper says the twin will sip 15.1 gallons an hour at 75% cruise and has a maximum cruise speed of 178 knots and a maximum range of 1,083 nautical miles
I think this is fantastic! I hope Delta Hawk is wildly successful with their line of new engines. Diesel technology makes so much sense for GA aircraft (it’s so simple), and anything that helps move GA away from 100LL is welcome.