Optimization methods for ULM PrandtlPlane design and preliminary flight tests

The lifting system of a PrandtlPlane aircraft is a box wing, with two swept lifting wings and two vertical tip wings. This paper shows the design and the methodologies used to design a class of PrandtlPlane ULM aircraft, including high and low speed aerodynamic solutions. The PrandtlPlane ULM aircraft are designed in order to meet the requirements of high visibility, low noise in cabin, low stall speeds, possibility to design hydroplanes and, primarily, to enhance the safety. Due to a lack of information on this innovative configuration, it has been realized that a set of test flights are necessary to achieve a manned prototype. A 1:5 scaled model has been manufactured and tested in flight at Ferrara Aero Club. Even though the model scale is too small to obtain final conclusions, the test results are in accordance with the mathematical model of the aircraft. A new 1:3 scaled model is now in progress. Finally, some perspectives of the PrandtlPlane ULM configuration are discussed at the light of the theoretical and flight test results