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Abstract:The advantages associated to Vertical Short-Take-Off and Landing (V/STOL) have been demonstrated since the early days of aviation, with the initial technolology being based on airships and later on helicopters and planes. Its operational advantages are enormous, being it in the field of military, humanitarian and rescue operations, or even in general aviation. Helicopters have limits in their maximum horizontal speed and classic V/STOL airplanes have problems associated with their large weight, due to the implementation of moving elements, when based on tilting rotors or turbojet vector mechanical oriented nozzles. A new alternative is proposed within the European Union Project ACHEON (Aerial Coanda High Efficiency Orienting-jet Nozzle). The project introduces a novel scheme to orient the jet that is free of moving elements. This is based on a Coanda effect nozzle supported in two fluid streams, also incorporating boundary layer plasma actuators to achieve larger deflection angles. Herein we introduce a state-of-the-art review of the concepts that have been proposed in the framework of jet orienting propulsion systems. This review allows to demonstrate the advantages of the new concept in comparison to competing technologies in use at present day, or of competing technologies under development worldwide.

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This paper presents a theoretical model of Coanda attachment mechanisms and laws of the Coanda effect. In this paper, it has been considered a very conventional setup in order to define by a theoretical analysis a mathematical model of the Coanda adhesion. It has been produced a complete mathematical model which could allow simple engineering calculations through an effective solutions of the differential equations of the system. A parametric model has defined as a function of main cinematic and geometric parameters. The final model relates to three fundamental parameters: outlet section, Coanda surfaces radius and inlet velocities. Turbulent and laminar models have defined. Validation through a large CDF campaign has produced in a regime of stream velocities from 5 to 40 m/s with good results