HYBRID-ELECTRIC DRIVE SYSTEM FOR MULTI-ENGINE AIRCRAFT

The invention relates to a hybrid-electric drive system (10) for multi-engine aircraft (20). The drive system comprises at least one first and second hybrid-electric drive unit (31, 32), each of which has an internal combustion engine (41, 42), a motor-generator unit (71, 72), and a transmission (51, 52) for transmitting drive power to a propeller (61, 62). In a primary operating mode, the propellers (61, 62) obtain the drive power largely or completely from the internal combustion engine (41, 42), which is coupled to the respective transmission (51, 52). In a secondary operating mode, the first or second internal combustion engine (41, 42) provides drive power to the first or second propeller (61, 62) via the first or second transmission (51, 52), and the first or second motor-generator unit (71, 72) transmits drive power, wherein the electric power generated by the first or second motor-generator unit is transmitted to the second or first motor-generator unit (72, 71) via the transmission device (80), and the second or first motor-generator unit then transmits drive power to the second or first propeller (62, 61) via the second or first transmission (52, 51), the second or first internal combustion engine (42, 41) being deactivated or not transmitting any drive power. The invention is advantageous in that: first, the operating range of the thermal machines is optimized, and the specified fuel consumption is reduced; second, the construction is weight-optimized with respect to high-capacity battery-based hybrid designs; third, the operating time of the individual thermal machines is significantly reduced with an alternating usage with respect to the aircraft operating hours; and fourth, the operational safety is increased for a safety-relevant failure of a thermal machine and the prevention of asymmetrical thrust.