The electric aircraft industry is starting to gain traction mainly due to the growing specific energy capacity of new batteries. Within this industry electric vertical takeoff and landing (eVTOL) aircraft serve the urban and regional air mobility market, requiring less infrastructure investments such as large airports, due to their vertical takeoff and landing capabilities. The present study investigates the preliminary performance evaluation of a tandem wing long-rage eVTOL concept. First, the power and energy consumption of a typical mission with a range of 300 km is estimated, consisting of: vertical takeoff, climb, cruise, loiter, descent, and vertical landing. The takeoff, climb, descend and landing phases are simulated numerically. The climb performance is evaluated in vertical and horizontal configuration. The flight paths were optimized aiming at a minimum energy consumption, showing very high climb rates due to the large power needed for vertical takeoff. To quantify the effect of different payloads on the aircraft range, a payload range diagram is constructed. Next, a sensitivity analysis is performed with respect to some operational parameters, relating the range and mission block speed to cruising altitude, cruise speed and wind speed. Finding the sensitivity of the flight range to these input parameters allows one to adequately select the safety margins for a given battery capacity. Finally, a conclusion and recommendation for next studies is given.@en