Four hour forty minute flight for Quaternium HYBRiX.20

Quaternium, a leading European brand of long-endurance multirotors, has flown for 4 hours and 40 minutes with their HYBRiX.20 fuel-electric quadcopter. They believe that this flight time beats any former demonstration ever made with an electric, hybrid of hydrogen multicopter HYBRiX.20 RPA was designed by Quaternium in 2014 and its first model was built in ["]