Unmanned Systems Technology 026 I Tecdron TC800-FF I Propellers I USVs I AUVSI 2019 part 1 I Robby Moto UAVE I Singular Aircraft FlyOx I Teledyne SeaRaptor I Simulation & Testing I Ocean Business 2019 report

Exploded view of the UAVE (Courtesy of Robby Moto) 72 Dossier | Robby Moto UAVE rotational speed is typically 4000-5000 rpm, so the fast charging times of a capacitive system are unnecessary,” Costa says. “CDI is common among UAV engines mainly because it is useful for two-strokes.” The UAVE is port injected, with two EV 14 injection valves from Bosch integrated onto the manifolds situated at the lower front corners of the engine which feed into each cylinder. These top- feed conical injectors spray fuel at an operating pressure of 3 bar, up to a 5 bar maximum. The engine’s injection, ignition and throttle systems are controlled by the ECU. “We use the EURO4 PPC from EFI Technology as our ECU,” says ECU engineer Mattia Durantini. The EURO4 measures about 165 x 95 mm and uses a 32-bit CPU (specifically, a 40 MHz PowerPC unit) with 32 kbytes of RAM, 512 kbytes of flash storage and a further 8 Mbytes for additional data logging. An electronic throttle body (with a redundant throttle position sensor) from Bosch is integrated on the top- right of the airbox and controlled with what is called a speed density strategy. This uses data inputs on manifold air pressure (MAP) from a Bosch Pressure Sensor Combined PST 1/PST 3 unit, and on crankshaft speed from the phonic wheel mounted between the distribution gear and the forward counterweight, to maintain the fuel-to-air ratio. The injection system is controlled and timed using inputs from these two sensors as well as a lambda sensor and a magnetic camshaft speed sensor. Ignition timing is managed using inputs from the lambda, crank and cam sensors. The injectors are also corrected using sensors for water and oil temperatures, for example to provide additional fuel to compensate for the colder temperatures at start-up. An oil pressure sensor is used to control the oil pump to ensure the pressure does not drop too low and risk lubrication failure. The ECU provides a CAN bus that serves as the sole comms and control link from the various engine sensors to the aircraft. A 12 V supply connects the ECU to the ignition coils, fuel injectors, throttle and lambda sensor, with an additional 5 V link to the MAP, oil pressure and throttle position sensors. Conclusion Following further dynamometer tests this year, Robby Moto plans to conduct experimental flight testing for the UAVE. Findings from these will be used to continue maturing the engine’s capabilities and, if past projects are any indication, to inform the company’s future projects in the aerospace and automotive sectors. June/July 2019 | Unmanned Systems Technology The distribution gear is linked to each camshaft by a pair of steel Morse chains that run from the gear to driven sprockets on the cams (Author’s image)