Unmanned Systems Technology 004 | Delair-Tech DT18 | Autopilots | Rotron RT600 | Unmanned surface vehicles | AMRC | Motion control | Batteries

44 Autumn 2015 | Unmanned Systems Technology Specifications Wankel-type Twin rotor Effective displacement, 600 cc Naturally aspirated Unleaded 95 octane gasoline Aluminium structure Nickel silicon carbide-coated working surface Steel eccentric shaft Steel rotor Twin plugs, single injector per rotor Engine management system Peripheral porting design Maximum rpm, 7500 The twin-rotor RT600 has side plates and a centre plate sandwiching its rotor housings, all five elements being fastened together by 13 bolts. The trochoid housing has a nickel silicon carbide-coated working surface, against which run iron- based apex seals. Similar material is used for the corner and side seals. In total, each rotor has 15 seals – three apex and six corner and six side (three per side face). All these seals are uncoated, and all are spring-loaded using a steel leaf in the seal groove. A combination of air and water cooling is used, the former using the charge in the case of the LCR version. Fuel is lifted from the tank by an electric pump and then fed through a regulator into the common fuel rail that supplies the two injectors, one for each rotor. The CDI ignition is twin coil, providing one coil for both plugs on each rotor, which consequently fire simultaneously, triggered directly by the engine management system. The engine management system operates the two ignition coils, the two injectors and (via a servo) the butterfly throttle for each rotor. It also controls the operation of the two oil pumps. EMS inputs are eccentric shaft position sensor (a 12+1 trigger wheel), throttle position sensor, water temperature and air temperature and pressure. The temperature of cooling air exiting the rotor is measured as a vital guide to internal operating conditions. No oil temperature or pressure sensing is needed given the oiling system used. The alternator is located on the non-drive side, combined with the trigger wheel and a counterbalance weight, all three items rotating together. The trigger wheel acts as the starter ring gear, and two intermediate gears connect the starter motor to it. The water pump is also at this end. There is another counterbalance weight on the output side. The RT600 twin-rotor engine in gasoline-powered LCR form weighs 21.2 kg. That is the core block including a 600 W generator, less exhaust, starter motor and so on. The single-rotor RT300 equivalent weighs 11.9 kg. The core RT600 engine is 31 cm long, 18 cm wide and 22 cm high. The twin-rotor engine will typically have extensions of the side and centre plates designed to act as solid mountings into the airframe. Given the engine’s lack of vibration when balanced correctly, hard mounting is normal. To strip and rebuild an RT600 takes no more than five hours, and under pressure it could be quicker. Key suppliers to the RT600 Rotor working surface coating: Poeton Injectors: Bosch EMS: GEMS Servos: Volz Spark plugs: NGK Precision shapes: Portland Engineering Castings: Invertacast Laser cutting: Freshlook Hard anodising: Acorn Bearings: Eriks Seals: Eriks Machine tools: XYZ Anatomy of the RT600 Key components of the RT600