When the Air Force put out a request for a 50-100 bhp turboprop, I knew I could use our IP and hardware and come out ahead of the other programmes 89 propeller. The engine flow path is similar to that of the Pratt & Whitney Canada PT6 engine family, with an inlet that can face forwards or backwards for pusher or tractor configurations; for simplicity, we will treat the air intake here as the ‘front’ of the engine. The system runs on JP4, JP-8 and Jet-A, with further testing planned for evaluating its performance on JP-5 and diesel. Aant Farm has also completed the design and started fabrication of the TA65-1, a version of the engine that replaces the gearbox with a brushless high-speed alternator. Also set to weigh 30 kg, it is designed to produce 60 kW from the main alternator and a further 5 kW from its starter/alternator. As the former solution is much further along in development however, the main focus here will be on the TPR72. Development history Aant Farm’s origins date back to 1990, when M-DOT Aerospace was contracted by the US Army MICOM (now the Aviation and Missile Research, Development and Engineering Center) to design, fabricate and test an ultra lowcost turboprop for uncrewed vehicles that had used a Sundstrand (now Pratt & Whitney) expendable turbojet as the gas generator core. Success of the SBIR Phase 1 of this work led to a Phase 2 award to create a new centreline design, designated the TPR80-1, and a prototype of this engine was produced and tested. “At the time though, the team behind the IAI RQ-5 Hunter Short-Range UAS programme [the development plan by which that uncrewed aircraft was scheduled to become the US Army’s short-range UAV for division and corps commanders] was looking for a heavy fuel engine,” Seegers recalls. “So we designed our engine to fit their aircraft’s cowl, and related packaging constraints defined the prop size and speed for the engine and gearbox, to the point that the Hunter became the original intended platform for the productionised TPR80. “Both simple-cycle and recuperated versions of the engine were designed but, owing to SBIR Phase 2 funding limits, we were only able to bring the simplecycle version to the testing stages of that project. Since then, I’d wanted to pursue development of the recuperated version. “My decision to restart development came in 2018, when I saw an Air Force Research Laboratory SBIR solicitation for a 50-100 bhp turboprop. I knew I could leverage our existing IP and hardware, bring in private money and come out way ahead of the government programmes.” What followed was a hardware-heavy development programme to modernise and optimise the overall engine, with Seegers and Weier drawing on their experience in solid modelling, cycle analysis, stress Aant Farm TPR72 | Dossier Uncrewed Systems Technology | August/September 2023 One TPR72 is currently being dyno-tested to develop the starting fuel supply schedule and the lubrication system, while another is due for thermodynamic performance tests
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