Issue 41 Unmanned Systems Technology December/January 2022 PteroDynamics X-P4 l Sense & avoid l 4Front Robotics Cricket l Autonomous transport l NWFC-1500 fuel cell l DroneX report l OceanScout I Composites I DSEI 2021 report

32 Dossier | PteroDynamics X-P4 Because the Transwing uses the same propulsion system for VTOL and cruise flight, any fixed-pitch system will be a compromise, but a variable-pitch propeller set-up would solve that. We would be very excited to find a group interested in developing that with us.” Whitehand adds, “We are also exploring things such as different propeller solidities and acoustics. Our customers aren’t necessarily looking for those right now, and using unusual propeller designs can add risk, but we want to know how to add efficiency so that we’re ready when the market demands it.” Barring some unexpected leap forward in the commercialisation of new, high-density battery chemistries, PteroDynamics expects to use some form of hybrid power unit in the future for customers requesting longer flight times, greater carrying capacities or just reduced downtime. Gasoline, heavy fuel and hydrogen systems alike are open for consideration, including IC engines and fuel cells. Microturbines suited to the X-P4’s weight class, efficiency requirements and MTBF remain rare. Meanwhile, the electric motors are controlled by Currawong Engineering ESCs, chosen for their long life and reliability. Whitehand and Dr Petrov emphasise that ESCs often come up as the highest-risk components during UAV failure analyses, being routinely subjected to surges that can break them and hence the powertrain. Aero The shape of the X-P4, particularly its high aspect ratio wing, outwardly resembles a glider more than an archetypal high-speed aircraft. Initial designs of its profile were calculated and conceived based on first engineering principles and available bodies of empirical data. “We are putting more resources into the analytical modelling of the Transwing to identify opportunities for optimisation and establish a strong technical basis on which to scale the technology; however, we place a high priority on flight testing to support our claims,” says Whitehand. Structural design and materials The structural design of the X-P4 is largely driven by experience-based decision-making combined with selective use of FEA and mechanical testing. Airframe materials and mechanical architectures were selected with a heavy emphasis on manufacturability and cost. Its airframe is made predominantly from a minimum gauge (thinness) composite sandwich structure using carbon, Kevlar and fibreglass. Core materials include low-density closed-cell polyethersulfone foam and balsa wood. High-load December/January 2022 | Unmanned Systems Technology PteroDynamics X-P4 VTOL-transitioning UAV Wingspan: 4 m Length: 2 m MTOW: 34 kg Payload volume: 28 litres Standard battery energy: 2.2 kWh Standard payload capacity: 6.8 kg Maximum payload capacity: 11.8 kg Maximum endurance: 3 hours Maximum speed: 280 kph Cruising speed: 105 kph MTBF: At least 100 hours Some key suppliers Autopilot & controls: Applied Navigation Autopilot & controls: KH Unmanned Autopilot & controls: Aerial Robotics Australia Autopilot & controls: Mayan Robotics Aerodynamic analysis consultation: Flighthouse Engineering Mechanical design consultation: Flighthouse Engineering Airframe r&d: Tumbleweed Composites Fuselage manufacturing: Composites Universal Group Wings and vee-tails: Ultimate Composites Folding propellers: GM Propellers Additional propeller consultation: Mejzlik Electric motors: Hacker ESCs: Currawong Engineering PteroDynamics X-P2 VTOL-transitioning UAV Wingspan: 2 m Length: 1.03 m MTOW: 10 kg Payload volume: 3 litres Standard battery energy: 0.7 kWh Standard payload capacity: 2.2 kg Maximum payload capacity: 3.1 kg Maximum endurance: 2 hours Maximum speed: 150 kph Cruising speed: 95 kph Some key suppliers Autopilot & controls: Applied Navigation Autopilot & controls: Mayan Robotics Airframe manufacturing: Vibe Composites Folding propellers: GM Propellers Electric motors: T-Motor ESCs: Mezon Specifications