Issue 54 Uncrewed Sytems Technology Feb/Mar 2024 uWare uOne UUV l Radio and telemetry l Rheinmetall Canada medevacs l UUVs insight DelltaHawk engine l IMU focus l Skygauge in operation l CES 2024 report l Blueflite l Hypersonic flight

64 DeltaHawk Engines is a Wisconsin-based company, dedicated to the development of compression-ignition engines for crewed and uncrewed small aircraft. Though seemingly a newcomer among UAV powertrain manufacturers, it was actually founded almost three decades ago, by Diane Doers, Doug Doers and John ‘JP’ Brooks – the former an experienced businessperson and the latter two being militaryturned-civilian pilots. The three were motivated to found DeltaHawk in 1996 by what they saw as conspicuous flaws in general aviation (GA) engine designs. By and large, these were air-cooled engines integrating magnetos, carburettors and other old technologies. Such engines are maintenance-intensive, fuel-inefficient and rarely lasted up to 1000 hours between overhauls. In their view, modernising GA engines meant creating one that was easier to operate, had far fewer points of failure, was more fuel-efficient and could run on many different fuels. Most GA engines run on avgas, which is limited in availability to Europe and North America (and is being phased out due to its lead content). Compression ignition was soon identified as key to making their engine run on widely available fuels such as kerosenes and diesels, and within a year an 80 HP (60 kW) prototype had been produced. As multi-fuel engines are highly valued among UAV operators, this is the market that DeltaHawk is targeting today, in common with other GA engine companies we have featured, such as Austro Engine (issue 4, Summer 2015) and ULPower (issue 45, August/ September 2022). Over 27 years, the team has accrued investments, key personnel and technologies optimised for their envisioned engine – along with a high number of patents to protect them – and Type Certification from the FAA in 2023, a rarity among UAV powertrains. That certified powertrain is DeltaHawk’s first commercially available Rory Jackson investigates how this compression-ignition two-stroke engine achieved FAA Type Certification Higher and higher February/March 2024 | Uncrewed Systems Technology The DHK180 is a 3.3 litre V4, originally designed and built by DeltaHawk to overcome the fundamental inefficiencies in general aviation engines (all images courtesy of DeltaHawk)