Mobile Ground Station for the Unmanned Elettra-Twin-Flyer Airship

In recent years the development of unmanned platforms has exasperated the concept of design and planning in aeronautics: for unmanned flight, in fact, the aerial segment is no longer the central issue and concepts like mission planning, mission and on board sensor management are becoming more and more critical. The majority of these functionalities have been separated from the aerial segment and transferred to the Ground Station (GS) which is one of the key elements of the Unmanned Aerial System (UAS) together with the Communication Link and the Launch and Recovery Element. Safety requirements are thus transferred to some of the GS components, especially to those which perform critical functions. This has contributed to increase the CS complexity. Regardless of the UAV architecture and overall dimension, in fact, the pilot must be able to operate under the same condition of situation awareness of a correspondent manned aircraft. In this context, advanced vision systems and innovative human-machine interfaces must be designed, to enable the pilot to process the flight data while accomplishing the mission task. This paper presents a technological solutions adopted for the Elettra-Twin-Flyer, a lighter-than-air unmanned platform, developed for civil applications

Structure Design for the Elettra Twin Flyer Prototype

This paper presents different structural solutions compared under the same manoeuvrability and operativity requirements. The structures to be analysed are chosen from an initial set, selected among many solutions which fulfil the dimensional requirements. The airship, in fact, has to be big enough to accommodate a pre-determined volume of payload, has to accommodate the motors in pre-defined locations to allow a good manoeuvrability while limiting the structural deformations, must be able to house all the systems necessary for its operation and should be able to contain enough volume of helium as to sustain at least the 95 % of the structure weight. To minimize the costs of the structural analysis two configurations has been selected as the most representative of the many configurations proposed: the non-rigid double-hull (Figure 1) and the rigid soap-shape airship (Figure 2). Among the available aeronautical technologies, the aluminium truss and the carbon sandwich structures have been considered for the exoskeleton of the soap-shape airship. On the other hand, the structure of the double-hull is too complex to be realized by standard aluminium components, so only the carbon sandwich solution has been analysed

Innovative airplane ground handling system for green operations

The aim of this work is to develop a new concept of taxiing, in order to reduce the pollution in terms of noise and gas emission and to introduce a higher level of safety during ground operations. In the area close to the airport gates, the airplane ground handlings are currently performed through the airplane engines, which have the task of providing the trust necessary to move the airplane to the runway. Pollutant emissions and the noise level near the gates, however, could be drastically reduced by introducing an innovative autonomous tractor called CHAT (Clean Hydrogen Autonomous Tractor), developed from the standard pushback tractor. The ground operations could be basically modified by extending the time in which the airplane engines are idle and the airplane is towed by the tractors powered by renewable energy

Alternative procedure to verify the H-V diagram after external installations on helicopters

Certification of external installations on helicopters, for modifications for which CS27/29.865 is not applicable, often requires the showing of compliance of paragraph CS XX.79 - Limiting height-speed envelope – which might imply, ultimately, a certain degree of H-V testing. Due to the implications on safety during the investigation of the H-V curve, a preliminary analytical investigation is advisable, to understand whether H-V test can be drastically reduced. Analytical investigation, though, is usually based on the extensive use of simulation data, based on validated dynamic mathematical models, which are usually not available to the applicant. TPS recently proposed an alternative method, based on the analysis of a set of flight tests, which is meant to assess the different phases of the physical/mechanical phenomena related to the emergency maneuver performed by the pilot as a consequence of a power loss, within or in the proximity of the H-V curve. More in details, the analysis of the autorotation phenomenology reveals that the maneuver is made up by different phases and dedicated tests have been proposed to assess each of these phases. The whole test campaign is hence meant to gain a thorough insight of how, and specifically in which part of the maneuver, the external modification could affect the helicopter H-V characteristic. Depending on this substantiation, H-V testing can be avoided or drastically reduced, limiting the investigation to a few meaningful points. The proposed method has been recently assessed by TPS on an external basket installation, making use of purposely developed TPS’s Flight Instrumentation and post-processing tools. More in details, results and conclusions are based on the analysis of static and dynamic flight parameters, acquired with a non-intrusive FTI, which monitors and correlates cockpit parameters and flight commands, following a back-to-back approach (i.e. pre and post modification). The method demonstrated was witnessed by EASA and found acceptable as an alternative method for showing of compliance to the applicable requirements

Alternative procedure to verify the H–V diagram after external installations on helicopters

Certification of external installations on helicopters, for modifications for which CS27/29.865 is not applicable, often requires the showing of compliance of paragraph CS XX.79—limiting height-speed envelope—which might imply, ultimately, a certain degree of H–V testing. Due to the implications on safety during the investigation of the H–V curve, a preliminary analytical investigation is advisable, to understand whether H–V test can be drastically reduced. Analytical investigation, though, is usually based on the extensive use of simulation data, based on validated dynamic mathematical models, which are usually not available to the applicant. The authors recently proposed an alternative method, based on the analysis of a set of flight tests, which is meant to assess quantitatively the different phases of the physical/mechanical phenomena related to the emergency maneuver performed by the pilot as a consequence of a power loss, within or in the proximity of the H–V curve. More in details, the analysis of the autorotation phenomenology reveals that the maneuver is made up by different phases and dedicated tests have been proposed to assess each of these phases. The whole test campaign is hence meant to gain a thorough insight of how, and specifically in which part of the maneuver, the external modification could affect the helicopter H–V characteristic. Depending on this substantiation, H–V testing can be avoided or drastically reduced, limiting the investigation to a few meaningful points. The proposed method has been recently assessed on an external basket installation, making use of purposely developed Flight Instrumentation and post-processing tools. More in details, results and conclusions are based on the analysis of static and dynamic flight parameters, acquired with a non-intrusive Flight Test Instrumentation, which monitors and correlates cockpit parameters and flight commands, following a back-to-back approach (i.e., pre- and post-modification). The method demonstrated was witnessed by EASA and found acceptable as an alternative method for showing of compliance to the applicable requirements

Ground testing of the ETF unmanned airship technology demonstrator

This paper deals with the ground testing of the technological demonstrator of the innovativeremotely controlled ETF airship. The testing activities are intended to validate the flight control system of the ETF, which is based on the thrust vectoring technology and represents one of the major innovations of the ETF design, together with the airship architecture. A research team of the Aeronautical and Space Department of the Polytechnic of Turin, in collaboration with Nautilus, a small Italian private company, has been working since a few years on the ETF (Elettra Twin Flyers). This airship is remotely-piloted, with high maneuverability capabilities and good operative features also in adverse atmospheric conditions. The Nautilus new concept airship features architecture and appropriate command system, which should enable the vehicle to maneuver in forward, backward and sideward flight and hovering with any heading, both in normal and severe wind conditions. To achieve these capabilities the ETF demonstrator3 has been conceived with a highly non conventional architecture based on a double hull with a central plane housing structure, propellers, on board electric system and payload . As primary command system, the aerodynamic control surfaces are replaced by six propellers, which are moved by electrical motors and allow the airship to be controlled and maneuvered in the whole flight envelope. In this paper the results of the preliminary testing runs are analyzed and the power requirement is compared with the performance of the Fuel Cell system, purposely developed for the ETF Demonstrator

Innovative Hydrogen Storage Tank for Flying Fuel Cell Power System

More and more often aerospace designers are considering hydrogen PEM (Proton Exchange Membrane) fuel cells for the on-board power system. Nowadays, the use of these systems is limited to aircraft that require low power demand such as small UAVs and ultra-light airplanes. This solution has always been considered appealing, but just recently has started to become also practical because of the dramatic decreasing of the specific weight of the fuel cell stack

Structural and Aerodynamics Analysis on Different Architectures for the Elettra Twin Flyer Prototype

This paper deals with the design and development of an innovative airship concept which is remotely-controlled and intended to be used for monitoring, surveillance, exploration and reconnaissance missions. Two potential solutions have been analyzed: the first consists of a double-hull configuration, characterized by the presence of a primary support structure connected by appropriated bindings to a couple of twin inflatable hulls. The second architecture is a soap-shaped exoskeleton configuration which features a single inflated section, incorporating two separate elements held internally by a system of ribs. The aim of this study is to analyze and compare the two configurations, to determine the most appropriate solution in terms of performance, cost and maneuvering capabilitie