Tilt-duct Unmanned Aerial Vehicles (UAV) combine the high-speed efficiency of fixed-wing aircrafts with vertical takeoff and landing (VTOL) and the hover capabilities of rotary-wing aircrafts while maximizing the advantages of ducted fans in terms of noise reduction. efficiency. and safety. making it a pivotal direction for the future of aviation such as urban air mobility. http://www.mamapaisa.com/product-category/moisture-treatment/