In recent years, the applications of multirotor have increased day by day and have found their position in every industry. The focus of this research is on the new application of heavy multirotor in the field of UAV recovery. The system studied in this research is called FLARES, which is a commercial product of a well-known American company. First, all methods of retrieving UAVs without the need for a runway are described, and in the next step, the multirotor engineering design for this application is studied. Then the dynamic and control equations of the FLARES system are extracted for the states of without and with a winch. Due to the specific nature of the problem, a super-twisting sliding mode controller is proposed for this system and simulations are run in different states. Finally, according to the analysis of simulation results, the components of these heavy multirotor are selected. This research is concerning one of the new multirotor applications. Keywords: UAV recovery, FLARES, Super-twisting sliding mode controller, UAV recovery with multirotor, Design of heavy multirotor, Multirotor applications