Unmanned Systems Technology 014 | Quantum Tron | Radio links and telemetry | Unmanned Aerial Vehicles | Protonex fuel cell | Ancillary systems | AUVSI 2017 Show report

50 B oeing subsidiary Insitu specialises in UAV design, development and manufacture, and supplies its fixed-wing ScanEagle to the US military and commercial users. The ScanEagle has a 10 ft wingspan, and since it was first deployed in 2004 it has been powered by a naturally aspirated, small-displacement, spark-ignited two- stroke engine. In a quest for superior performance and reliability, Insitu recently developed its own internal combustion engine (ICE), the project undertaken in conjunction with Orbital as described in UST issue 8. This bespoke 50 cc two-stroke exploits Orbital’s unique direct injection technology, and running on jet fuel produces 2.4 kW. The air-cooled single is used as a ‘pusher’ in the ScanEagle (in other words, the propeller is at the rear). The Insitu-Orbital engine core is augmented by a fuel supply system, an oil supply system, an engine management system, a muffler, a generator and a bespoke propeller. All those items will be replaced though by a fuel cell (FC) powertrain that Insitu is working with Protonex to develop. However, the ScanEagle will be otherwise unmodified, so that it will be straightforward to switch between ICE and FC electric propulsion. Background The only inputs to a fuel cell are oxygen from the atmosphere and hydrogen gas; its outputs are electricity, water vapour and heat (see sidebar, page 56). Protonex is owned by Ballard Power Systems, well-known for its fuel cells for the likes of buses and fork lifts, and which is undertaking development of fuel cells for cars on behalf of the Volkswagen Group. Before its acquisition by Ballard in 2015 Protonex, which was founded in 2000, developed soldier-carried fuel cells. Developed under contract from the US Department of Defense, they showed promise in trials but were ultimately abandoned owing to the logistics of Ian Bamsey looks at the development process behind replacing this UAV’s internal combustion engine with a fuel cell powertrain Straight switch June/July 2017 | Unmanned Systems Technology Protonex fuel cell propulsion unit for the ScanEagle (left) and (right) the fuel cell module