Citation: Frigioescu, T.-F.; Condruz, M.R.; Badea, T.A.; Paraschiv, A. A Preliminary Study on the Development of a New UAV Concept and the Associated Flight Method. Drones 2023, 7, 166. https://doi.org/ 10.3390/drones7030166 Academic Editor: Mostafa Hassanalian Received: 2 February 2023 Revised: 22 February 2023 Accepted: 25 February 2023 Published: 27 February 2023 Copyright: © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). drones Article A Preliminary Study on the Development of a New UAV Concept and the Associated Flight Method Tiberius-Florian Frigioescu, Mihaela Raluca Condruz * , Teodor Adrian Badea and Alexandru Paraschiv National Research and Development Institute for Gas Turbines COMOTI, 220D Iuliu Maniu Av., 061126 Bucharest, Romania * Correspondence: raluca.condruz@comoti.ro Abstract: This article presents a preliminary study on the development of a new concept for an unmanned aerial vehicle (UAV) design that incorporates the use of four wings and attached sys- tems to improve overall performance, it being classified as a hybrid quadcopter (a quad tilt wing, tiltrotor UAV). By simulation, it was determined that the developed concept has significant ad- vantages compared with a conventional quadcopter. By implementing this concept, an increase in the maximum speed by 59.21% can be obtained; it reduces time to complete a 10 km route by 36.4%, decreases the energy consumption by 37%, and increases the maximum travel distance by 56.9% at 30% remaining battery capacity. Additionally, the concept improves maneuverability by allowing turning movements to be performed by changing the angle of incidence of the rear wings, resulting in less energy consumption compared to traditional turning methods applied in the case of a conventional quadcopter. Keywords: UAV; tiltrotor; quadcopter; concept; flight method 1. Introduction 1.1. Definition and History of UAVs In the latest decades, an increased interest was registered for the UAV sector, and much research was conducted to develop several UAV types and UAV control systems. Different institutions use several terms to describe the UAVs; the literature presented them as unmanned aerial systems (UAS), remotely piloted vehicles (RPVs), and drones, but different from precision-guided munition. For example, the International Civil Aviation Organization (ICAO) defined the unmanned aircraft as “an aircraft which is intended to operate with no pilot on board” and the unmanned aircraft system as “an aircraft and its associated elements which are operated with no pilot on board”. Moreover, they refer to the remotely piloted aircraft as a subcategory of unmanned aircraft [1]. The Federal Aviation Administration (FAA) from the U.S. Department of Transporta- tion define the unmanned aircraft as “a device used or intended to be used for flight in the air that has no onboard pilot. This includes all classes of airplanes, helicopters, airships, and translational lift aircraft that have no onboard pilot. Unmanned aircraft are understood to include only those aircraft controllable in three axes and therefore, exclude traditional balloons” [2]. The European Aviation Safety Agency (EASA) define the UAS as “an individual system elements consisting of an “unmanned aircraft”, the “control station” and any other system elements necessary to enable flight, i.e., “command and control link” and “launch and recovery elements”. There may be multiple control stations, command and control links and launch and recovery elements within a UAS” [3]. The precursors of flight and unmanned aircraft date to the ancient world, but the first modern unmanned aircraft was demonstrated in 1916 by inventors Hewitt and Sperry, who designed and manufactured the “Hewitt-Sperry Automatic Airplane” [4]. Drones 2023, 7, 166. https://doi.org/10.3390/drones7030166 https://www.mdpi.com/journal/drones