Design, control, aerodynamic performances, and structural integrity investigations of compact ducted drone with co-axial propeller for high altitude surveillance oleh Shyam Sundar Jayakumar, Indira Prasanth Subramaniam, Beena Stanislaus Arputharaj, Senthil Kumar Solaiappan, Parvathy Rajendran, It Ee Lee, Senthil Kumar Madasamy, Raj Kumar Gnanasekaran, Arunkumar Karuppasamy, Vijayanandh Raja