65 product, the DHK180, a 162 kg, twostroke engine producing up to 180 HP (134.2 kW). It is certified to run on Jet A and Jet A-1, but it can also run optimally on JP-8, D1, D2 and F-24. It is a liquidcooled aircraft engine, oiled via dry sump, turbo- and supercharged. DeltaHawk designed it at each turn for simplicity and redundancy, such that it runs without needing an ECU for any injection, induction, cooling or other requirements. From the first 80 HP prototype to today’s 180 HP product, it has remained a 3.3 L, 90° V4 engine for direct-drive aircraft applications. Challenges to solve However, making it work consistently and reliably has been more challenging, explains Dennis Webb, DeltaHawk’s director of certification, an FAA DER (Designated Engineering Representative and hence the FAA’s eyes on the company), a 2000-hour instrumentrated pilot and also a licensed professional engineer since 1979. “Over the decades there have been more versions and iterations of the block alone than any of us can really count confidently, until we cast the ideal material and machining geometry. There were literally thousands of engineering problems and subtle issues that we had to resolve,” Webb recounts. “Here’s one example: typical piston pins are designed for four-stroke engines, where on the end of the exhaust stroke you get a slight gap between the pin and the piston boss, and oil sneaks into that gap so that the pin gets lubricated. That doesn’t happen in two-strokes because you’re always compressing, so getting a piston pin to live long in a high-performance, two-stroke diesel is really hard. “There are dozens more niche but serious problems like that, which we worked really hard to solve. For instance, we’ve spent millions of dollars developing our unique fuelling system and getting it to work.” In addition to the FAA and Webb approving roughly 20,000 pages of DeltaHawk DHK180 | Dossier Over the decades there have been more iterations of the block alone than any of us can really count confidently, until we cast the ideal material Uncrewed Systems Technology | February/March 2024 DeltaHawk anticipates that the engine will usually run as a direct-drive, inverted-vee, with key aerodynamics and visibility gains from keeping the propeller up top, above the cylinders
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