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Technical Paper

Thermojet: An Old Idea Can Define a Novel Family of Jets

2013-09-17
2013-01-2205
This paper investigates the ancient idea of augmenting the thrust produced by a rotating fan by producing a thermal gradient by heating the outflow. Some of the pioneers of aeronautics have originally conceived this idea: the indirect jet (Bleriot Coanda Monoplane, 1910) and the “thermojet” (Caproni-Ciampini CC2, 1942). They were abandoned because of the better performances by traditional jets such as the ones developed in Germany and USA during 2nd World War. Antony Colozza (NASA), one of the modern fathers of high altitude airships, has recently proposed it again to be used on fuel cells powered airplanes and airships. Most fuel cells have a large thermal dispersion at high temperature (about 40%), but it could be possible to use it for heating the propulsive stream of high-speed air produced into ducted fan propulsive units.
Technical Paper

Temperature Oscillations in the Wall of a Cooled Multi Pulsejet Propeller for Aeronautic Propulsion

2016-09-20
2016-01-1998
Environmental and economic issues related to the aeronautic transport, with particular reference to the high-speed one are opening new perspectives to pulsejets and derived pulse detonation engines. Their importance relates to high thrust to weight ratio and low cost of manufacturing with very low energy efficiency. This papers presents a preliminary evaluation in the direction of a new family of pulsejets which can be coupled with both an air compression system which is currently in pre-patenting study and a more efficient and enduring valve systems with respect to today ones. This new pulsejet has bee specifically studied to reach three objectives: a better thermodynamic efficiency, a substantial reduction of vibrations by a multi-chamber cooled architecture, a much longer operative life by more affordable valves. Another objective of this research connects directly to the possibility of feeding the pulsejet with hydrogen.
Technical Paper

Safety Analysis of an Airship Which Loses Lifting Gas from the Hull

2018-10-30
2018-01-1954
This study investigates the physical phenomena that affect a high-altitude airship in the presence of lifting gas losses from the hull. General atmospheric thermodynamics and basic physical principles are adopted to describe the behavior of an airship with envelope failures that generate buoyant gas dispersion or depressurisation phenomena. Overpressure that could grant to maintain some controllability during a large part of the descent is assessed by mean of the thermodynamic model of the envelope in the presence of gas losses. Optimisation of the inflation parameters is provided and the conditions for avoiding dangerous crashes on the ground and the potential recovery of a damaged vehicle, people and its payload. In particular, the requirements for a slow depressurisation is computed by the equilibrium with the atmosphere and then how can it be possible to sustain controlled navigation are determined.
Technical Paper

Roto-Cycloid Propelled Airship Dimensioning and Energetic Equilibrium

2014-09-16
2014-01-2107
Rotocycloid propulsion presents interesting performance as a possible long-term alternative to helicopters in a far future. It will lead to increase the energy efficiency of VTOL vehicles. This paper focuses on optimization of an airship with the possibility up to 2000 h/year of photovoltaic propelled flight at a cruise speed about 20 m/s. This paper demonstrates the feasibility of this airship concept and presents a full dimensioning according to the CDE (Constructal Design for Efficiency) developed at University of Modena and Reggio Emilia. The proposed solution has been deeply analyzed and the analysis of performances has been presented. The results allow thinking to a novel class of vehicles designed specifically to take the maximum advantage by this propulsion method.
Journal Article

Quite-Rigid Airship Structure Concept and Design for Enhanced Hovering Capability

2012-09-10
2012-01-1892
This paper explores a novel structural design concept for a demonstrator of a high altitude photovoltaic feeder airship. The presented structural design concept aims to minimize the use of strategic materials in the structure of the airship, but also to maximize the ease of construction of the structure. The proposed design concept and method an effective analysis of historic airship structures considering their efficiency vs. weight and desired performances. By this analysis a novel structural design has been defined to reach the ambitious goal of a lighter and cheaper structure concept which can ensure comparable performances with traditional rigid airships. A discoid shaped airship with a central column has been taken into account. Structural calculations and constructive design has been presented in depth.
Journal Article

Propulsion of Photovoltaic Cruiser-Feeder Airships Dimensioning by Constructal Design for Efficiency Method

2013-09-17
2013-01-2303
The European project MAAT (Multi-body Advanced Airship for Transport) is producing the design of a transportation system for transport of people and goods, based on the cruiser feeder concept. This project defined novel airship concepts capable of handling safer than in the past hydrogen as a buoyant gas. In particular, it has explored novel variable shape airship concepts, which presents also intrinsic energetic advantages. It has recently conduced to the definition of an innovative design method based on the constructal principle, which applies to large transport vehicles and allows performing an effective energetic optimization and an effective optimization for the specific mission.
Technical Paper

Preliminary Implementation Study of ACHEON Thrust and Vector Electrical Propulsion on a STOL Light Utility Aircraft

2015-09-15
2015-01-2422
One of the best airplanes ever realized by the European Aircraft industry was the Dornier Do 28D Skyservant, an extraordinary STOL light utility aircraft with the capability to carry up to 13 passengers. It has been a simple and rugged aircraft capable also of operating under arduous conditions and very easy and simple maintenance. The architecture of this airplane, which has operated actively for more than 20 years, is very interesting analyzing the implementation of a new propulsion system because of the unusual incorporation of two engines, as well as the two main landing gear shock struts of the faired main landing gear attached to short pylons on either side of the forward fuselage. This unconventional design allows an easy implementation of different propulsion units, such as the history of different experimental versions allowed.
Technical Paper

Optimization of Airships with Constructal Design for Efficiency Method

2013-09-17
2013-01-2168
It is possible to define a novel optimization method, which aims to overcome the traditional Multidisciplinary Design Optimization. It aims to improve Constructal design method to optimize complex systems such as vehicles. The proposed method is based on the constructal principle and it is articulated in different stages: 1 preliminary top-down design process to ensure that the full system has one of the best configurations for the specified goals (contour conditions for constructal optimization could be stated ensuring an effective optimization at full-system level). 2 constructal optimization of the elemental components of the system to maximize the system performances; 3 eventually a competitive comparison between different configurations choosing the better one. The definition of an optimized flying vehicle (an airship) has been produced an example of this improved design method with the objective of minimizing the energy consumption during flight.
Technical Paper

Numerical and Experimental Second Law Analysis of a Low Thickness High Chamber Wing Profile

2018-10-30
2018-01-1955
This paper presents a coupled numerical and experimental study of an unconventional wing profile such as cp-180-050-gn (Cambered plate C = 18% T = 5% R = 0.78). This wing profile deals with low speeds. It is not currently used on any aircraft model. Otherwise, it presents interesting performances that can be exploited for the design of low-speed STOL or VTOL aircraft by mean of the very high lift that it can generate and can fit with different uses such as VAWT, cyclorotors drones, which are designed explicitly for low-speed operations. After a preliminary CFD assessment of the wing a complete experimental characterisation also at high angles of attack has been performed. The excellent agreement between CFD and experiments has allowed producing a complete analysis of the behaviour of the wing profile both before and after stall conditions. This study has the objective of analysing the viability of such an unconventional wing in traditional or over-stalling conditions.
Technical Paper

Multifunctional Unmanned Reconnaissance Aircraft for Low-Speed and STOL Operations

2015-09-15
2015-01-2465
This paper presents a novel UAS (Unmanned Aerial System) designed for excellent low speed operations and VTOL performance. This aerial vehicle concept has been designed for maximizing the advantages by of the ACHEON (Aerial Coanda High Efficiency Orienting-jet Nozzle) propulsion system, which has been studied in a European commission under 7th framework programme. This UAS concept has been named MURALS (acronym of Multifunctional Unmanned Reconnaissance Aircraft for Low-speed and STOL operation). It has been studied as a joint activity of the members of the project as an evolution of a former concept, which has been developed during 80s and 90s by Aeritalia and Capuani. It has been adapted to host an ACHEON based propulsion system. In a first embodiment, the aircraft according to the invention has a not conventional shape with a single fuselage and its primary objective is to minimize the variation of the pitching moment allowing low speed operations.
Technical Paper

Multibody Advanced Airship for Transport

2011-10-18
2011-01-2786
The MAAT project (Multibody Advanced Airship for Transport) aims to investigate aerial transportation possibility by airship based cruiser-feeder system. MAAT is composed by two modules: The cruiser, named PTAH, (acronym of Photovoltaic Transport Aerial High altitude system); the feeder, named ATEN (Aerial Transport Elevator Network feeder), is a VTOL system (Vertical Take Off and Landing) which ensure the connection between the cruiser and the ground. They can lift up and down by the control of buoyancy force and displace horizontally to join to cruiser.
Technical Paper

MAAT Cruiser/Feeder Project: Criticalities and Solution Guidelines

2011-10-18
2011-01-2784
MAAT project is a large airship project presented to the last European 7 Framework Program Transport including Aeronautics 2011 deadline. MAAT project is an airship based cruiser-feeder transport system. This paper analyzes the criticalities of the project and the way to upfront these problems which have different natures and possible solutions. Most important criticalities are analyzed both on a methodological point of view and on a direct point of view. Enhanced design methodologies are analyzed in depth to analyze problems, upgrade the project design status continuously and to examine different design options and solutions. An innovative design method has been defined to avoid that problems can produce show stoppers and minimize time delays during project definition.
Technical Paper

MAAT Cruiser/Feeder Airship: Connection and Passenger Exchange Modes

2013-09-17
2013-01-2113
In the general framework of the EU FP7 MAAT project, a novel green air transport architecture is under development. The paper presents the possible architectures for the cabin connections and the transfer modalities for people, crew and freight, for to the European project MAAT. Different architectures have been evaluated setting out to cover the structural and propulsive needs and to enable the transport modes between the Cruiser and the Feeders. The different possibilities are discussed conceptually, by considering the advantages and disadvantages of the presented configurations. The bases for future detailed design and research are established, as through such conceptual study the main parameters are identified and found to affect the general design of both airships and their operability. The aim of this paper is to specify the necessary elements, which are necessary to perform the docking operation by taking into account the prescribed Feeder-Cruiser geometries.
Technical Paper

Infrared Piloted Autonomous Landing: System Design and Experimental Evaluation

2014-09-16
2014-01-2196
This paper introduces a new equipment, which allows autonomous landing and docking of a VTOL aircraft and any mobile system. It has been studied and developed inside the MAAT (Multibody Advanced Airship for Transport) EU FP7 project to control autonomous docking of manned cruiser and feeder airships in movement. After a detailed analysis it has been verified that It could be considered a technological spin off the MAAT project. It defines a new instrumental system for governing relative positioning between a movable target and VTOL air vehicles, such as helicopters, airships and multi-copters. This solution is expected to become a short time to market equipment for helicopters (both manned and unmanned) ensuring autonomous landing ability even in case of low visibility. Infrared emitters allow controlling both position and yaws angle. It is in advanced testing phase after a preliminary successful testing using a quadcopter.
Technical Paper

Increasing Aeronautic Electric Propulsion Performances by Cogeneration and Heat Recovery

2014-09-16
2014-01-2106
Emissions from aviation have become a focus of increasing interest in recent years. The growth of civil aviation is faster than nearly all other economic sectors. Increased demand has led to a higher growth rate in fossil fuels consumption by the aviation sector. Despite more fuel-efficient and less polluting turbofan and turboprop engines, the growth of air travel contributes to increase pollution attributable to aviation. Aircraft are currently the only human-made in situ generators of emissions in the upper troposphere and in the stratosphere. The depletion of the stratosphere's ozone layer by CFCs and related chemicals has underscored the importance of anticipating other potential insults to the ozone layer. Different possible solutions have been advanced to reduce the environmental impact of aviation, such as electrification of ground operations, optimization of airline timetables and airspace usage, limitation of cruise altitude and increased use of turboprop aircrafts.
Journal Article

Fire-safe Airship System Design

2012-02-29
2012-01-1512
This paper presents the new Hydrogen Fire-safe Airship system that overcomes the limitations present in previous airships designs of that kind, when considering their functioning at advanced operative position. Hydrogen is considered to be more effective than helium because of its low-cost production by hydrolysis, which process is nicely driven only by the photovoltaic energy. This paper presents a novel architectural concept of the buoyant balloon designed to increase the fire related safety, when applying hydrogen as the buoyant gas. The proposed buoyant volume is designed as a multi-balloon structure with a naturally ventilated shape, to ensure that hydrogen cannot reach the dangerous concentration level in the central airship balloon. This concept is expected to be the start of a novel hydrogen airship type, to be much safer than preceding ones.
Technical Paper

Energy Self Sufficient Aircrafts Can Become Reality through New Propulsion Design Approaches

2015-09-15
2015-01-2484
This paper focuses on the key problem of future aeronautics: which relates on energy efficiency and environmental footprint on a scientific point of view. Reducing emissions and increasing the energy efficiency would be both a key element to propel the market and increase the diffusion of personal aerial transport against ground transportation. Novel vehicle concepts and systems will be necessary to propel this innovation which could revolutionize our way of moving. This paper approaches an energetic preliminary design of a vehicle concept which could fulfill this social and cultural objective. Low cost energy efficient vehicles, which could be suitable for personal use with a high economic efficiency and without needs of airports, seem actually a real dream. Otherwise, is it a feasible goal or a scientific dream? Otherwise, a design method based on first and second law and thermodynamic and constructal law could allow reaching those goals.
Technical Paper

Energetic, Environmental and Range Estimation of Hybrid and All-Electric Transformation of an Existing Light Utility Commuter Aircraft

2018-10-30
2018-01-1933
Today it is necessary to face the energetic, environmental, and safety-related issues of a significant industrial sector such as aeronautic one. It is a marginal contributor to today global GHG emissions (less than 3%), In any case, the associated impacts grows with the increase of air traffic with annual rate 5%. Consequently, aviation will need to face four fundamental problems for the future: 1 the overall impact of aviation is expected to grow up to 10÷15% of global GHG emissions by 2050; 2 the emissions of pollutants by commercial aviation affects the fragile atmospheric layers in the low stratosphere; 3 the increasing age of the flying fleet deals with increasing maintenance and safety issues; 4 the dependence on fossil fuels relates to problems of geopolitical instability and consequence volatility of prices. Substantial innovations are expected for both reducing energy consumption and environmental impacts of aviation and reducing the age of the fleets.
Journal Article

Energetic Design and Optimization of a Large Photovoltaic Stratospheric Unconventional Feeder Airship

2012-10-22
2012-01-2166
This paper presents a model of energetic consumption and photovoltaic production for a large airship which acts as feeder connecting the ground with a large cruiser. The analysis of energy needs and productivity allows defining both an ideal sizing and operative mission profiles. The specialised mission of this airship is to ascent and descent. It includes also the connection with the airport buildings on the ground and with the cruiser at high altitude. Photovoltaic production has evaluated in terms of hydrogen and electric propulsion. They have estimated both and a calculation methodology has proposed. The evaluation has supported by CFD evaluations on aerodynamic behaviour of the system at various altitudes.
Technical Paper

Design of ACHEON Thrust and Vector Propulsion System

2015-09-15
2015-01-2425
This paper focuses on the calculation methodology of the thrust of a ACHEON propulsion system, which is based on Coanda effect deflection of thrust. It defines a calculation methodology based on integral equations. The proposed methodology allows an effective calculation of the performances and the force applied on the airplane by such a propulsion system. It will also allow an effective design of the nozzle system and will implement also internal elements with an accurate definition of frictional losses. Outstanding results have been obtained together with general rules for implanting ACHEON propulsion inside an aircraft.
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