Unmanned Systems Technology 019 | Navya Autonom Cab | Batteries | UGVs Insight | UAV Factory UAV28-EFI | Swiss Aerobotics Hummel | UMEX 2018 report | Antennas | Oceanology International 2018 report

56 Dossier | UAV Factory UAV28-EFI developed its own port injection operated by its own engine control unit (together with the ignition and throttle) on an open- loop basis. The company has also developed its own exhaust, including a very effective silencer, and its own cooling package, including revised cylinder head finning and bespoke ducting with outflow controlled by the ECU according to cylinder head temperature. The cooling cowl encloses the cylinder (with just the top of the spark plug projecting through) while the C-shaped silencer wraps around the bottom end. The Penguin C module includes a fuel tank with integral firewall at the back. The firewall carries the engine, which is thus cantilevered from the front of its crankcase, attached via four anti-vibration mounts. Wrapping around the throttle body assembly and containing various fuel system components, the carbon fibre composite firewall is cold-bonded to the carbon fibre composite fuel tank ahead to form a single structural unit. The ECU sits in a bay formed in the top of the fuel tank section, and all power unit wiring and plumbing is contained in the module. Charge air is collected from within the engine compartment and is fed into the throttle body through a filter, which uses K&N material bonded into UAV Factory’s own mounting frame. The throttle body contains a butterfly-type throttle and feeds into the crankcase through a reed valve, with the fuel injector positioned between the butterfly and the reed housing, angled at 30 º . The single miniature solenoid fuel injector is capable of very fine atomisation and is fed fuel at 2.5 bar. It works in conjunction with CD ignition firing a single 10 mm plug. The sophisticated electronic control system of both ensures clean burn, to the benefit of time between overhauls (TBO). General development Popiks notes, “We use a third-party [core engine] as this is not a critical component – we use it from a cost- effectiveness perspective as its use is not directly related to the reliability of the power unit as a whole. The major parameter as far as we are concerned is to make a reliable aircraft by having a very good MTBF of the entire system. We will sacrifice every other parameter to improve that one, which is the main driver of the cost of operating a UAV. “At the start, we used a number of specialist UAV engines that were equipped with a carburettor from various different manufacturers. We April/May 2018 | Unmanned Systems Technology The integrated Penguin C power unit module Karlis Putnieks (left) and colleague Roberts Muiznieks in the UAV Factory engine testing cell