The energy autonomy of UAVs is an important direction in the field of aerospace. Long-endurance aerial vehicles allow for continuous flight; however, to meet the guidelines, the power supply system has to be able to harvest energy from outside. Solar cells allow the production of electricity during the day when the sun shines on their surface. Depending on the location, time, weather, and other external factors, the energy produced by PV panels will change. In order to calculate as accurately as possible the energy obtained by solar cells, we developed a simulation model that took into account all of the external restrictions and the UAV’s limits during flight. The conducted analysis made it possible to obtain information for the specific input data on whether the UAV is able to fly for 24 h in a specific flight scenario. The UAV powered by solar cells developed by us and the performed aviation missions have shown that the UAV is capable of continuous flight without the need to land.

A vertical take-off and landing (VTOL) is a type of unmanned aerial vehicle (UAV) that allows for flight in harsh weather for surveillance and access to remote areas. VTOL can be performed without a runway. As such, VOTL UAVs are used in areas where there is limited space and in urban locations. The structural endurance of VTOL UAVs is limited and is further reduced in the case of fixed-wing UAVs. Long-endurance aerial vehicles allow for continuous flight, but their power supply systems must be able to harvest energy from external sources in order to meet the guidelines. The wings of these UAVs are often covered with solar cells. This article presents the extended range and flight time of a tail-sitter VTOL that incorporates solar cells on the UAV structure. A VTOL powered by solar cells can perform aviation missions with fewer landings, allowing for the performance of such UAVs to be increased and for their flight time to be extended several times over those without solar cells. Simulations accounting for the use of PV panels on the UAV structure show that depending on the scenario and flight date, VTOLs can double the flight time on the spring equinox and increase the flight time by more than six times on the summer solstice.

Climate change currently taking place around the world requires humanity to take decisive action. One way, as envisaged in the European Green Deal, is to reduce the emissions of harmful chemical compounds of the transport sector by 90% by 2050. This reduction also applies to aviation. The most commonly suggested means of achieving this goal is the electrification of aviation. In this paper, the possibilities of using small general aviation aircraft (for up to two people) with electric propulsion used for sport flying, particularly for pilot training and glider towing, have been analysed. For this purpose, simulation models have been developed in MATLAB/Simulink environment for three different tasks: cross-country flight, performing a certain number of touch-and-go procedures during one flight, and towing a glider. Three aircraft representing different classes were selected for analysis: Diamond DA20 Katana, WT-9 Dynamic, and PZL-101 Gawron. Based on data collected from pilots and publicly available flight records, minimum performance requirements for particular tasks were determined. The number of batteries that power the electric propulsion system of the analysed aircraft was selected in such a way that no geometrical changes in the aircraft structure are necessary and the MTOW (Maximum Take Off Weight) is not exceeded. Obtained results indicate the possibility of using small electric aircrafts derived from UL (ultralight) class in flights taking place near airports, performing touch-and-go procedures and towing gliders.