No abstract

The IDINTOS project, co-founded by the Regional Government of Tuscany (Italy), concerns the design of a ultralight amphibious PrandtlPlane and the manufacturing of a flying prototype. A consortium of universities and private companies participated to the project, coordinated by University of Pisa. The paper describes the general design of the aircraft, including aerodynamics, hydrodynamics, structures, propulsion, undercarriages and interior design etc. The aircraft presents a PrandtlPlane wing configuration in order to improve the aerodynamic efficiency and to enhance the safety with respect to stall and manoeuvrability. The control surfaces (ailerons and elevators) are located on both front and rear wing so that the flight mechanics results different with respect to the conventional aircraft. The solution adopted for the propulsion system consists of two ducted propellers that are set laterally on the fuselage. The flap system is made of Fowler flaps in the front wing and plain flaps in the rear one. The interior design of the cabin has been oriented towards a better ergonomic position of the passengers whereas the dispositions of the commands wants to minimize the possibility of any human errors.

This paper summarizes the main activities conducted to design, optimize and build a prototype of an innovative light amphibian. This aircraft is a "PrandtlPlane", a particular box-wing configuration which introduces relevant advantages as increased aerodynamic efficiency and safety of flight; the research project, called IDINTOS, has been co-funded by the Regional Government of Tuscany (Italy), coordinated by the University of Pisa and carried out in 30 months by a consortium of public bodies and small private firms, starting from 2011. In this contribution an overview is given also on several aspects concerning the design, as the aerodynamic optimization, the construction and tests of three scaled models for towing tank wind tunnel and, flight tests, respectively. * Results shown in this paper have been achieved during the research project "IDINTOS", funded by Tuscany Region

This paper deals with the evaluation of the flight dynamics response of aircraft with a PrandtlPlane configuration by means of simple models to be used during the preliminary design. The study is completed by method that allows an initial sizing of the elevator and the aileron in such the way adequate requirements can be achieved: this analysis becomes important when the control surfaces can be located in both the front and the rear wing. The flight dynamics model is carried out considering the aircraft rigid, the steady aerodynamics, and separating the longitudinal and the lateral-directional motions. In this way classic equations are considered; for both the phugoid and the short period, equations are extended taking also the Zq derivative into account because of the non-conventional wing configuration. The force derivatives are extrapolated through a VLM solver whose the reliability of the results has been proven. The sizing methods have been applied to a test case derived from the project IDINTOS; as general results, the study remarks the possibility to obtain proper longitudinal dynamic response with a reduced longitudinal Stability Margin because of the very high values of the aerodynamic damping M q.

Wind tunnel tests have been carried out on a ¼ scaled model of a two seats amphibian PrandtlPlane. In the present paper, CFD analyses, conducted with the Star-CCM+ software in order to replicate the experimental results, are presented. First, the full-scale free-air conditions have been simulated with a k-ε model and the results compared with those for the ¼ scaled model; the effects of the different Reynolds numbers are discussed. Then, by adding the elements connecting the model to the wind tunnel, i.e. the pylon and the walls, new simulations have been carried out with significant effects in the case of some aerodynamic derivatives. Finally, in order to improve the agreement between experimental and CFD results, further studies have been conducted with a fixed transition k-ω turbulence model. The results of the CFD analyses are exposed and discussed, the advantages and the disadvantages of k-ε and k-ω models are compared and general conclusions are given on the role of CFD and wind tunnel in the aerodynamic design of a modern aircraft and, more in particular, of the amphibian PrandtlPlane at hand.