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1 – 10 of over 2000Miroslaw Rodzewicz, Dominik Glowacki, Tomasz Szczepanik and Jaroslaw Hajduk
The purpose of this paper is to describe the results of investigations of parachute rescue systems (PRS) for light gyrocopters.
Abstract
Purpose
The purpose of this paper is to describe the results of investigations of parachute rescue systems (PRS) for light gyrocopters.
Design/methodology/approach
Although the investigations were conducted in both stages simultaneously, i.e. experimental mechanics approach and numerical simulations, the paper is focussed mainly on the experimental part of the work. To ensure the safety of experimental works (i.e. for both experimenters and bystanders), the authors applied unmanned, remotely controlled scale models of autogyro for the PRS testing in the air.
Findings
The critical problem for successful use of the PRS is that the rotation of the rotor blades must be stopped when the main parachute opens, otherwise the influence of the rotor on the improper opening process of the parachute may cause the whole PRS to become useless.
Research limitations/implications
The existing regulations for the use of unmanned aircraft impose the limitation upon the organisation of in-flight tests of PRS, i.e. the maximum take-off mass of the tested gyrocopter models is limited, and a full-scale test needs the approval of European Aviation Safety Agency (EASA).
Practical implications
The research contributes to increasing the safety level for gyrocopter users. The authors elaborated the original PRS, which currently is in the process of patenting.
Originality/value
Originality of the work consists of both an innovative PRS, which has never been tested before, and the results of experimental investigations, which cover both ground tests carried on static or moving stands and in-flight testing.
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Federico Barra, Matteo Scanavino and Giorgio Guglieri
The primary purpose of this study is to analyse the performance of multirotor unmanned aircraft system platforms for passenger transport and compare them with an ordinary…
Abstract
Purpose
The primary purpose of this study is to analyse the performance of multirotor unmanned aircraft system platforms for passenger transport and compare them with an ordinary helicopter solution. This study aims to define a standard procedure for power budget analysis of unconventional vehicles recently proposed in the aerospace industry, providing guidelines on rotor sizing in terms of required power and the total number of rotors. The ultimate purpose of the proposed work is to describe a methodology for power estimation with regard to emerging electric vertical takeoff and landing (EVTOL) vehicles.
Design/methodology/approach
In the context of urban mobility, short-range passenger transport between critical hubs in cities is taken into account and innovative aircraft and traditional helicopters are compared according to a common mission profile. The power budget equations used in the helicopter literature are revisited to consider different multirotor configurations (up to 20 rotors) and evaluate the feasibility of innovative aerospace vehicle design.
Findings
The paper includes insights into the maximum number of rotors that ensure a significative, relative power reduction compared to helicopter platforms (the power-to-cruise over power-to-hover ratio appears to be improved). Based on this preliminary analysis, the results suggest the benefit of reducing the installed rotors to avoid excessive power loss in forward flight.
Practical implications
The proposed study provides guidelines for further design considerations and the future development of EVTOL multirotor aircraft.
Originality/value
This paper fulfils the identified need for a systematic approach on performance analysis for innovative vehicles involved in commercial applications.
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Marcelo Santiago Sousa, Pedro Paglione, Roberto Gil Annes Silva, Flavio Luiz Cardoso-Ribeiro and Sebastião Simões Cunha
The purpose of this paper is to present a mathematical model of one very flexible transport category airplane whose structural dynamics was modeled with the strain-based…
Abstract
Purpose
The purpose of this paper is to present a mathematical model of one very flexible transport category airplane whose structural dynamics was modeled with the strain-based formulation. This model can be used for the analysis of couplings between the flight dynamics and structural dynamics.
Design/methodology/approach
The model was developed with the use of Hamiltonian mechanics and strain-based formulation. Nonlinear flight dynamics, nonlinear structural dynamics and inertial couplings are considered.
Findings
The mathematical model allows the analysis of effects of high structural deformations on airplane flight dynamics.
Research limitations/implications
The mathematical model has more than 60 degrees of freedom. The computational burden is too high, if compared to the traditional rigid body flight dynamics simulations.
Practical implications
The mathematical model presented in this work allows a detailed analysis of the couplings between flight dynamics and structural dynamics in very flexible airplanes. The better comprehension of these couplings will contribute to the development of flexible airplanes.
Originality/value
This work presents the application of nonlinear flight dynamics-nonlinear structural dynamics-strain-based formulation (NFNS_s) methodology to model the flight dynamics of one very flexible transport category airplane. This paper addresses also the way as the analysis of results obtained in nonlinear simulations can be made. Comparisons of the NFNS_s and nonlinear flight dynamics-linear structural dynamics methodologies are presented in this work.
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Abstract
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Kazimierz Szumański, Jerzy Bereżański and Andrzej Szumański
The results of preliminary tests concerning estimation and widening of helicopter limiting manoeuvre abilities are presented. Research space applies to super‐ and…
Abstract
The results of preliminary tests concerning estimation and widening of helicopter limiting manoeuvre abilities are presented. Research space applies to super‐ and hipermanoeuvrability problems that are especially important for helicopters, because of better manoeuvrability influence on higher safety level and effectiveness in special applications. In airplane engineering, these types of tests are advanced and aerodynamic system improvements are introduced as well as thrust vector control. There are also new manoeuvres recognized for advanced manoevrability airplanes: Cobra, Kulbit, Hook, Bell, Herbst manoeuvre. Although helicopter is “originally” thrust controlled, systematic researches on this field are still not conducted. The paper deals with the problem of helicopter flight mechanics at low flight speeds. The purpose of performed analysis is to achieve possibility of helicopter angular position control within wide range of angular displacements. This is performed by linear and centrifugal acceleration control. Rotor thrust vector control makes those accelerations appear.
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Khadeeja Nusrath T.K., Lulu V.P. and Jatinder Singh
This paper aims to build an accurate mathematical model which is necessary for control design and attitude estimation of a miniature unmanned rotorcraft and its subsequent…
Abstract
Purpose
This paper aims to build an accurate mathematical model which is necessary for control design and attitude estimation of a miniature unmanned rotorcraft and its subsequent conversion to an autonomous vehicle.
Design/methodology/approach
Frequency-domain system identification of a small-size flybar-less remote controlled helicopter is carried out based on the input–output data collected from flight tests of the instrumented vehicle. A complete six degrees of freedom quasi-steady dynamic model is derived for hover and cruise flight conditions.
Findings
The veracity of the developed model is ascertained by comparing the predicted model responses to the actual responses from flight experiments and from statistical measures. Dynamic stability analysis of the vehicle is carried out using eigenvalues and eigenvectors. The identified model represents the vehicle dynamics very well in the frequency range of interest.
Research limitations/implications
The model needs to be augmented with additional terms to represent the high-frequency dynamics of the vehicle.
Practical implications
Control algorithms developed using the first principles model can be easily reconfigured using the identified model, because the model structure is not altered during identification.
Originality/value
This paper gives a practical solution for model identification and stability analysis of a small-scale flybar-less helicopter. The estimated model can be easily used in developing control algorithms.
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Agnieszka Kwiek, Cezary Galinski, Krzysztof Bogdański, Jaroslaw Hajduk and Andrzej Tarnowski
According to the study of the space flight market, there is a demand for space suborbital flights including commercial tourist flights. However, one of the challenges is to design…
Abstract
Purpose
According to the study of the space flight market, there is a demand for space suborbital flights including commercial tourist flights. However, one of the challenges is to design a mission and a vehicle that could offer flights with relatively low G-loads. The project of the rocket-plane in a strake-wing configuration was undertaken to check if such a design could meet the FAA recommendation for this kind of flight. The project concept assumes that the rocket plane is released from a slowly flying carrier plane, then climbs above 100 kilometers above sea level and returns in a glide flight using a vortex lift generated by the strake-wing configuration. Such a mission has to include a flight transition during the release and return phases which might not be comfortable for passengers. Verification if FAA recommendation is fulfilled during these transition maneuvers was the purpose of this study.
Design/methodology/approach
The project was focused on the numerical investigation of a possibility to perform transition maneuvers mentioned above in a passenger-friendly way. The numerical simulations of a full-scale rocket-plane were performed using the simulation and dynamic stability analyzer (SDSA) software package. The influence of an elevator deflection change on flight parameters was investigated in two cases: a transition from the steep descent at high angles of attack to the level glide just after rocket-plane release from the carrier and an analogous transition after re-entry to the atmosphere. In particular, G-loads and G-rates were analyzed.
Findings
As a result, it was found that the values of these parameters satisfied the specific requirements during the separation and transition from a steep descent to gliding. They would be acceptable for an average passenger.
Research limitations/implications
To verify the modeling approach, a flight test campaign was performed. During the experiment, a rocket-plane scaled model was released from the RC model helicopter. The rocket-plane model was geometrically similar only. Froude scales were not applied because they would cause excessive technical complications. Therefore, a separate simulation of the experiment with the application of the scaled model was performed in the SDSA software package. Results of this simulation appeared to be comparable to flight test results so it can be concluded that results for the full-scale rocket-plane simulation are also realistic.
Practical implications
It was proven that the rocket-plane in a strake-wing configuration could meet the FAA recommendation concerning G-loads and G rates during suborbital flight. Moreover, it was proven that the SDSA software package could be applied successfully to simulate flight characteristics of airplanes flying at angles of attack not only lower than stall angles but also greater than stall angles.
Social implications
The application of rocket-planes in a strake-wing configuration could make suborbital tourist flights more popular, thus facilitating the development of manned space flights and contributing to their cost reduction. That is why it was so important to prove that they could meet the FAA recommendation for this kind of service.
Originality/value
The original design of the rocket plane was analyzed. It is equipped with an optimized strake wing and is controlled with oblique, all moving, wingtip plates. Its post-stall flight characteristics were simulated with the application of the SDSA software package which was previously validated only for angles of attack smaller than stall angle. Therefore, experimental validation was necessary. However, because of excessive technical problems caused by the application of Froude scales it was not possible to perform a conventional test with a dynamically scaled model. Therefore, the geometrically scaled model was built and flight tested. Then a separate simulation of the experiment with the application of this model was performed. Results of this separate simulation were compared with the results of the flight test. This comparison allowed to draw the conclusion on the applicability of the SDSA software for post-stall analyzes and, indirectly, on the applicability of the proposed rocket-plane for tourist suborbital flights. This approach to the experimental verification of numerical simulations is quite unique. Finally, a quite original method of the model launching during flight test experiment was applied.
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For many years prior to the second World War the two volumes of Fuchs and Hopf on Aerodynamics and Flight Mechanics were standard text books in the German language. These books…
Abstract
For many years prior to the second World War the two volumes of Fuchs and Hopf on Aerodynamics and Flight Mechanics were standard text books in the German language. These books are now out‐of‐date and in consequence some six years ago Professor Schlichting and Dr Truckenbrodt were approached by Dr Springer, the publisher, with a request that they should write a modern successor to the Fuchs‐Hopf volumes. The volume under review is the first of a two‐volume work which they have undertaken. It is not surprising to find that the ground that they plan to cover is somewhat more limited than that of the earlier Fuchs‐Hopf books; the enormous development of the subject in the intervening years has made such a reduction of scope inevitable. In the two volumes it is proposed to cover fluid mechanics (Section A), wing theory (Section B) and the aerodynamics of aircraft including interference effects (Section C), but the mechanics of flight and the aerodynamics of propulsion are topics that are being left to other authors.
Lorenzo Trainelli, Alberto Rolando, Giovanni Bonaita and Paolo Chimetto
The paper aims to detail the educational flight testing activities performed at the Department of Aerospace Science and Technology at the Politecnico di Milano (DSTA-PoliMi)…
Abstract
Purpose
The paper aims to detail the educational flight testing activities performed at the Department of Aerospace Science and Technology at the Politecnico di Milano (DSTA-PoliMi), including the development of low-cost, reliable flight testing instrumentation (FTI) and the administration of the graduate course in flight testing.
Design/methodology/approach
The flight testing course program closely adheres to the typical content of an introductory course offered in a professional flight testing school. However, within academic courses, it has a unique feature: each student is required to plan, perform and report on a real flight test experience, acting as a flight test engineer. Educational activities in this framework have been successfully matched to applied research and technical support for private companies.
Findings
At the educational level, several elements arise that are rarely concentrated within a single course, such as multidisciplinary integration, individual conceive-design-implement-operate (CDIO) project, real-life experimental procedures and techniques, teamwork, communication and reporting, relation with non-academic partners.
Practical implications
Based on the development of a FTI system for light aviation and on the flight testing course, DSTA-PoliMi has built a solid capability in flight testing, introducing graduate students to this specific niche of expertise and empowering co-operation with companies in the light aviation environment, while offering capabilities and tools that are typically regarded as a prerogative of major aerospace companies.
Originality/value
The paper discusses an original approach to flight testing education in an academic setting that avoids the high costs and complexity connected to certified aircraft flight operations and instrumentation, nevertheless allowing the achievement of significant results, also in applied engineering research.
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THE development of undergraduate teaching in Aeronautical Engineering at Manchester University has followed a different pattern from that in most other Universities in this…
Abstract
THE development of undergraduate teaching in Aeronautical Engineering at Manchester University has followed a different pattern from that in most other Universities in this country. Although Osborne Reynolds carried out his famous experiments in the Engineering Department at Manchester, the teaching of Aeronautical Engineering grew out of Mathematics rather than out of Engineering. For a large proportion of the past 80 years the Chair of Applied Mathematics has been held by men eminent in the field of Fluid Mechanics: Lamb, Goldstein and Lighthill must surely be names well‐known to every aeronautical engineer. It was due to the initiative of Professor S. Goldstein that a separate Department of Fluid Mechanics was set up in 1946 under the direction of Mr W. A. Mair. At first it was natural that the emphasis should be on experimental work to complement the theoretical work carried out in the Mathematics Department. Later, however, although close relations with the Mathematics Department were still maintained, the Mechanics of Fluids Department developed into a separate entity making both theoretical and experimental contributions to fundamental knowledge.