Co-funded by the Regional Government of Tuscany in 2011, the project IDINTOS has been completed in August 2013, leading to the construction of an innovative ultralight amphibious aircraft. The characteristic feature of this airplane, which makes it different from all the present ones, is its box-wing system. Such configuration is the result of a research started in the ’80s at the University of Pisa (Italy) and coordinated by Prof. Aldo Frediani of the Civil and Industrial Engineering Department (Aerospace Section).
The idea of adopting a box-wing system to maximize aerodynamic efficiency, once airplane weight and wingspan are given, dates back to the ’20s and is due to one of the fathers of modern aerodynamics, Ludwig Prandtl. The research carried out in Pisa confirmed Prandtl’s results and, by taking additional aspects of aeronautical engineering into account, resulted in the application of such concept to aircraft of different categories, from the sport ultralight to commercial ones. In honour of the man who first realized the aerodynamic advantages of the box-wing, this aircraft architecture has been called “PrandtlPlane”. The project IDINTOS has been carried on by the Civil and Industrial Engineering Department (Aerospace Section) of Pisa University, as leader of the project , the Department of Energy Engineering , Systems of Land and Buildings of the same University, the Higher Institute for Artistic Industries of Florence, and the Tuscan firms EDI Progetti e Sviluppo, MBVision , Dielectrik , Humanware , CGS and DAXO .
When the PrandtlPlane configuration is applied to large commercial aircraft, the main advantage is its highly aerodynamic efficiency that has obvious effects on fuel consumption and environmental impact.
In the case of small aircraft, instead, the greatest benefits can be found in flight safety. In fact, thanks to an intrinsic anti-stall behaviour and the presence of control surfaces on both wings, the PrandtlPlane is able to reduce the probability that a human error could be the cause of accidents and other dangerous situations.
In order to achieve the main objective of the project, i.e. the construction of a two-seater prototype with an internal combustion engine, the partners worked closely together, going to cover various milestones. Among these, the experimental activities performed to evaluate the hydrodynamic and aerodynamic characteristics of the amphibian have great importance. Tests on scaled models, respectively 1/3 and 1/4, have been carried out at the towing tank of the CNR-INSEAN in Rome and at the wind tunnel of Politecnico di Milano. In both experimentations, the models and different components of the test equipment have been manufactured by partners with the help of local suppliers. Another important milestone is the aircraft design, which has been focused on aeronautical issues, such as aerodynamics, flight mechanics and composite structures, but also on the mechanics and cabin interiors.
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