Unmanned Systems Technology 013 | AutonomouStuff Lincoln MKZ | AI systems | Unmanned Underwater Vehicles | Cosworth AG2 UAV twin | AceCore Neo | Maintenance | IDEX 2017 Show report

56 Dossier | Cosworth AG2 UAV twin is split transversally into front and rear sections, which is structurally superior to a longitudinal split. The halves are sealed by an O-ring and secured by eight bolts – four on top (between the barrel sealing faces) and four underneath. Crankshaft The crankshaft is a one-piece steel production that runs in three main bearings, the rear two of which flank the fuel pump. The blind front main bearing is a cylindrical roller, with its rollers running directly on the crankshaft. The cylindrical roller centre main bearing likewise has its inner race formed by the crankshaft, while to allow for assembly the crankcase captures a split outer race. The rear main bearing is the thrust bearing and is a deep-groove ball bearing with its own races. Between the front and centre bearings are front and rear webs counterweighted for balance plus a minimal central ‘flying’ web tying the two crankpins together. The rotary valve is sandwiched between the front web and the front of crankcase bulkhead, which carries the front main bearing. The rear web is formed to act as the timing wheel. The counterweighted webs are skeletal rather than full round, consequently the timing teeth form only part of the circle of a trigger wheel. However, the portion that is formed is active around the crucial triggering phase when injection takes place. This approach avoids the additional weight and complexity inherent in a separate trigger wheel. Since the front main bearing is blind, no sealing is required. Behind the rear main bearing, the crankshaft projects from the crankcase to drive the generator rotor, so there is a seal at that point. The drive is by means of a collar that has multiple holes for lightness, with half-a- dozen of the holes forming the threads for the rotor attachment screws. Six bolts attach the stator to the crankcase. April/May 2017 | Unmanned Systems Technology The AG2’s power and torque The AG2 has a rear-facing exhaust system, whereas its predecessor, the AG1, had a forward-facing one The crankshaft is a one-piece steel production that runs in three main bearings, the rear two of which flank the fuel pump