104 Show report | Xponential Commercial Part 2 rated for vacuum conditions, high levels of shock and vibration,” said Jeff Randall at Maxon. “One recent space application involved using a frameless, brushless DC motor from our DT [Dynamic Torque] motor family, and configuring it with a dualredundant winding in the stator, essentially packaging two independent motors into this one solution. That system was used in solar array deployment, so that if one winding failed, the motor could still extend the solar array so the spacecraft could replenish its energy.” Included within its range of space-rated solutions is the EC4-pole 22 SPACE, a brushless DC motor rated for 90 W and measuring 22 mm in diameter. The product weighs 175 g, functions on a 48 V DC input and can operate in ambient temperatures from -20C to over 100C. The company also exhibited several of its new UAV propulsion motors in diameters of 22-90 mm. With their ESCs, they are configured to achieve minimal weight while retaining lifespan and reliability. Among the larger solutions in Maxon’s propulsion range is the EC 87 flat UAV, which is a 87 mm-diameter, 309.5 g brushless motor, designed to produce up to 9 kg of thrust with a maximum speed of 6500 rpm, consuming up to 22.3 maximum continuous current. Additionally, the UAV ESC 52/30 CAN is one of the larger ESCs, which communicates using the DroneCAN v1 protocol and commutates motors via sensorless FOC. It weighs 102 g, including cable and housing, and it is designed to deliver up to 30 A continuously (90 A peak) to e-motors at just over 99% efficiency. Hirth Engines is working on a series of updates to enhance its two-stroke, two-cylinder, 41-Series engine with technologies not yet used elsewhere across its engine portfolio. “The engine is undergoing a facelift to have a smaller exhaust and possibly a new coating in the cylinder,” said Torsten Windorfer at Hirth. The new (undisclosed) coating is expected to make the spark-ignited, air-cooled engine more reliable over long endurances, and extend the TBO slightly by reducing the rate of scratches and ensuring against failures internally. It may also increase the engine’s 8 hp output by about 5% due to reduced friction of the piston against the cylinder wall and less blow-by. “We are now simulating the new, smaller exhaust for optimised resonances along the length of the port, which will also increase horsepower by around 5%,” Windorfer added. The German company is updating its 23-Series engine, targeting 10% more power output for the 50 bhp system, as well as increased torque, partially through a similarly redesigned exhaust system, but also via a new injection system. “We’re well-versed in different kinds of direct injection that we could implement, and now we’re also looking into transfer port injection,” Windorfer explained. “The latter may turn out to be better for inline engines, like our 35-Series [Issue 36], because of packaging advantages, but we’re also looking into it for the opposed-twin engines. Meanwhile, we have a new FEM simulation tool for examining how weight could be removed from any and every part, so we have big weight-reduction targets we want to reach too.” August/September 2024 | Uncrewed Systems Technology Maxon’s brushless DC motor Hirth’s 2301 engine prototype
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