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

45 Rotron RT600 UAV rotary engine | Dossier near one corner to allow for expansion with temperature. It is used in conjunction with corner seals as well as side seals. In the rotary engine the apex seals act as valves, opening one chamber to the intake port while simultaneously closing the chamber ahead, and so on. It follows that the geometry of the intake and exhaust port openings is crucial in terms of the timing of intake and exhaust opening and closing. The two rotor housings and the two side and centre plates are fastened together by 13 bolts that run through those five elements, arranged in a circular pattern around the periphery. “There is quite a lot of area to seal, around the sides where you have your combustion gases wanting to escape,” notes Cardozo. “There are O-rings all around all four structural interfaces, yet that many bolts are required to ensure a good seal.” Eccentric shaft The twin-rotor steel eccentric shaft runs in just two bearings, one in each of the side plates. On the output side a tapered spherical roller bearing is used, whereas on the other side is a regular roller bearing. “We developed the taper bearing for aero applications, as we found that when running the engine at sustained high power for long periods of time the bearing races would start eating into the shaft due to fretting,” reports Cardozo. “Having a taper bearing with its inner race locked onto the shaft overcame that fretting. It also takes up bending load created by the power strokes, which increases engine life.” Each side plate bearing is fed oil from its own solenoid-type oil pump that is driven according to a map in the ECU. Oil reaches the respective bearing via a gallery in its side plate. Having lubricated that bearing it leaks out to be drawn into the cooling airflow passing through the adjacent rotor. This creates an oil mist that lubricates the rotor’s needle roller bearing. With oil metered from the oil tank Unmanned Systems Technology | Autumn 2015 The RT600’s eccentric shaft While the majority of Rotron’s customers remain confidential, the company has announced an agreement to supply rotary engine power for CybAero’s new range of APID ONE unmanned helicopters