Unmanned Systems Technology 005 | Selex ES Falco UAV | Sense and avoid systems | RCV Engines DF70 | DSEI show report | Fuel cells | CUAV Expo, InterDrone and CUAV Show reports | SLAM

50 Dossier | RCV Engines DF70 UAV boxer twin The VRV is bolted to its drive gear by a single countersunk screw and is timed by a 2 mm dowel pin. In between the valve and its drive gear is sandwiched a conventional ball race, the outer ring of which is clamped into position in a counterbore formed in the top of the cylinder by the lower element of the timing drive gearbox. The ball race controls the vertical position of the VRV and allows it to rotate. It takes the radial gear separation forces and the axial load applied by cylinder pressure to the VRV. There are no sealing elements above the VRV aside from the gearbox top cover. There is also no sealing element between the exterior of the VRV and the bore within which it rotates; clearly that clearance alters with thermal expansion. Excessive clearance will result in loss of performance through gas leakage, while insufficient clearance will result in loss of performance as a consequence of Dec 2015/Jan 2016 | Unmanned Systems Technology Since this boxer engine causes little external vibration it can be rigidly mounted in the airframe. There are four bolts on the rear of the crankcase for attachment. It takes no more than 10 man- hours for a major overhaul including rebuilding with a calibration check and pass-off test. Key suppliers to the DF70 Engine structure: in-house Bore coating: Poeton Industries Crankshaft sourcing: HC Concepts Engineering Con rod sourcing: HC Concepts Engineering Timing gears: Biddle & Mumford Gears Pistons: in-house Rings: Stihl Piston pin sourcing: HC Concepts Engineering Big-end and main bearings: SKF Valves: in-house Ignition coils: Gill Sensors & Controls Spark plugs: NGK Fuel injectors: Honda Engine management system: GEMS Sensors: GEMS Data acquisition: GEMS Generator: Sullivan Products Exhaust: in-house Air filters: Ramair Wiring loom: Racelooms Fuel pump: TCS Micropumps Plasma nitriding: JJ Castings Metals: Wessex Metals Machining and fabrication: Manutech Manufacturing Machining: Bridge Precision Engineering FEA work: Advanced Analysis (AAL) Engine simulation software: Ricardo Anatomy continued… Fuel consumption and power readings for the DF70