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Aero-Structural Optimization of Joined-Wing Aircraft

Abstract

Joined-wing aircraft due to its energy characteristics is a suitable configuration for electric aircraft when designed properly. However, because of the specific for this aircraft phenomenons (e.g. static indeterminacy of structure, aerodynamic interference of lifting surfaces) it demands more complicated methods to model its behavior than a traditional aircraft configurations. For these reasons the aero-structural optimization process is proposed for joined-wing aircrafts that is suitable for preliminary design. The process is a global search, modular algorithm based on automatic geometry generator, FEM solver and aerodynamic panel method. The range of aircraft was assumed as an objective function. The algorithm was successfully tested on UAV aircraft. The improvement of 19% of total aircraft range is achieved in comparison to baseline aircraft. Time of evaluation of this global search algorithm is similar to the time characteristic for local optimization methods. It allows to reduce the time and costs of preliminary design of joined-wing.

Open access
Designing and Building Heavy Lifting Modification of a Radio Controlled Helicopter

Abstract

The paper presents the heavy lifting modification of radio controlled T-Rex 700 DFC PRO helicopter which was originally designed as acrobatic machine. The purpose of designing machine like this is a need for a cheap and reliable machine specifically designed to carry weights for research and development purposes. Thanks to its design there is a possibility to attach to it a measuring apparatus, modules like auto-pilot, and weights. It can be also used to test wide range of rotors and other components which makes it very universal research tool. To achieve those goals the whole frame and landing gear has been redesigned using NX 11 CAD/CAM/CAE to achieve desired cargo space and weight distribution. Additionally the tail has been lengthened to allow use of the rotors with bigger diagonal. All the applied changes has been made to increase the machine payload. The designed elements were fabricated and the helicopter has been tested in flight. During the test flights several performance parameters were measured.

Open access
Improvement and Optimisation of Gyroplane Performance

Abstract

The aim of this study was to investigate possibilities of improving performance characteristics of light gyroplane, as well to propose new or improved solutions enhancing performance of this type of rotorcraft. The study has been conducted based on computational methods of Computational Fluid Dynamics, Flight Dynamics, Computer Aided Design and Optimisation. Results of the research confirm that using advanced computational methods it is possible to improve significantly the performance characteristics of light gyroplane. It can be achieved both through optimisation of the main rotor design and flight control strategy. An unconventional approach to rotorcraft optimisation has been presented, distinguishing by the fact that the objective was calculated based on computer simulations of selected states of gyroplane flight. One of the optimised main rotors had already been examined during flight tests, which confirmed its good perfonnance-and-exploitation properties and its advantage over classic gyroplane rotors. Developed by the author the family of gyroplane airfoils is a valuable alternative to classic airfoils utilised so far. The same applies to the blades built based on those airfoils. In particular, it concerns the unconventional design of the rotor blade of span-variable: chord and relative thickness. The developed methodology of numerical optimisation of flight-control strategy during the jump takeoff of the gyroplane presents an original approach to those problems and may be valuable tool supporting gyroplane-pilot training.

Open access
Latin American Space Research - Challenges and Opportunities

Abstract

The interest of Latin American countries in space research has been successfully developing for many decades. It has its roots in the first development programmes for the Brazilian and Argentinian defence industry within the import substitution strategy, and then the export-oriented strategy during the period of the military rule. The endogenous development of space technology was treated in those countries as a priority and served as a way to diffuse technology to other industries, and as a model for the other countries in the region (Peru and Venezuela), which wished to develop outer space programme by developing their own technologies within the chosen range or by partaking in broader cooperation programmes on the Latin American continent [1]. The Latin American space agencies, which already existed in many countries in the 1960s and the 1970s, were carrying out relatively costly research, treating development in this area not only as the achievement of the economic development objectives, but also as an attempt to oppose the dominance of Washington [2]. Despite of the vast funding on endogenous research in the field of space engineering being provided, until the end of the last century only the projects conducted together with the Soviet Union (Cuba) or The United States were accomplished successfully. Currently and in the nearest future, the Latin American countries are still forced to rely on external assistance with satellite launching, expertise, more advanced technologies, etc. It should be noticed that countries conducting advanced and costly space programmes: the United States, Russia, China and the European Union (especially France and – but to a substantially lesser degree – Italy) show a growing interest in cooperation with Latin America and appreciation towards their specialists, high quality research and space technologies.

Open access
Preliminary Sub-Systems Design Integrated in a Multidisciplinary Design Optimization Framework

Abstract

The aircraft design is a complex subject since several and completely different design disciplines are involved in the project. Many efforts are made to harmonize and optimize the design trying to combine all disciplines together at the same level of detail. Within the ongoing AGILE (Horizon 2020) research, an aircraft MDO (Multidisciplinary Design Optimization) process is setting up connecting several design tools and competences together. Each tool covers a different design discipline such as aerodynamics, structure, propulsion and systems. This paper focuses on the integration of the sub-system design discipline with the others in order to obtain a complete and optimized aircraft preliminary design. All design parameters used to integrate the sub-system branch with the others are discussed as for their redefinition within the different detail level of the design.

Open access
Stress Distribution Investigation at the Tapered Sandwich Endings

Abstract

One of the typical sandwich ending is tapered transition to a solid laminate, which causes significant stress distribution changes. The reviewed articles show that tapered area causes increase in the shear stress in the core, increase of the axial forces in the facesheets and local bending at the fork point, at points of the tapering angle change, and at ply drop positions. Most of the studies gave attention to the endings without reinforcing. During Erasmus+ internship at KTH 2D model of the tapered ending with reinforcing plies, various geometry and resin filler in the core tip was investigated to see the influence on the stress distribution. It was found that tension load case is not as critical as bending load case. Increasing of the solid laminate thickness, adding plies and inserting a short resin or adhesive filler into the core tip area lead to significant stress reduction, whereas in the transition point, from tapering to constant thickness sandwich, increasing radius is more efficient than reinforcing plies in regard to reduce stress concentration.

Open access
Wind Tunnel Tests of Influence of Boosters and Fins on Aerodynamic Characteristics of the Experimental Rocket Platform

Abstract

The paper presents results of wind tunnel tests of the Experimental Rocket Platform (ERP), which is developed in Institute of Aviation. It is designed as an easy accessible and affordable platform for microgravity experiments. Proposed design enables to perform experiments in microgravity for almost 150 seconds with apogee of about 100 km.

The full-scale model of the ERP has been investigated in the T-3 wind tunnel in Institute of Aviation. During the investigation, the aerodynamic loads of the rocket has been measured for the angle of attack up to 10° and the different rotation angle around the longitudinal axis (up to 90°, depending on the configuration). Three configurations has been investigated:

• without fins and boosters

• with fins and without boosters

• with fins and boosters

Additionally, the measurements of velocity field around the ERP using the Particle Image Velocimetry (PIV) has been performed.

Based on the wind tunnel test, an influence of fins and boosters on aerodynamic characteristics of the rocket has been described. Results of the wind tunnel tests show relatively high contribution of boosters in total aerodynamic drag. Some conclusions concerning performance and stability of the rocket have been presented.

Open access
Individual Autonomous Navigation System

Abstract

The article presents the Individual Autonomous System Navigation (IANS) supporting–rescuer or firemen in terms of navigation. Basic assumptions, which such a system has to fulfill in terms of functionality and accuracy, are presented. The concept of the ISAN system is based on the implementation of inertial navigation system which the only one to permit fully autonomous functioning. Measurement sensors of the navigation system with microprocessor board are placed in the rescuer’s shoe. To limit the escalation of the navigation errors value, which in the case of inertial navigation rises exponentially, a procedure of navigation parameters upgrading at every step of the rescuer is introduced to the proposed system. This procedure guarantees the required accuracy of navigation achievement. The article describes a developed and manufactured demonstrator of the technology and presents main results of its research. The research conducted in a building consisted in walking on the same level several hundred meters in less than 10 minutes. A walking test with a change of walking height was also performed in order to estimate the accuracy of the vertical channel. Results of the demonstrator’s tests let us conclude that the error of navigation is below 1% of the travelled distance and the accuracy is linear in respect to time. The achieved accuracy is fully sufficient for a practical IANS application.

Open access
Infrared Signature Suppression Systems in Modern Military Helicopters

Abstract

Helicopters play an important role in air-to-ground fire covering and the short-distance air-to-air fights, as well as the anti-tank missions and battlefield force transferring. The detection and survivability of helicopters on a battlefield significantly depends on their infrared emissions level, as well as the methods, equipment and systems used by potential enemy. The automatic detection systems, recognition and identification of flying objects use among other the thermo-detection methods, which rely on detecting the infrared radiation emitted by the tracked object. Furthermore, due to low-altitude and relatively low flight speed, today’s combat assets like missile weapons equipped with infrared guidance systems are one of the most important threats to the helicopters performing combat missions. Especially meaningful in a helicopter aviation is infrared emission by exhaust gases, egressed to the surroundings. Due to high temperature, exhaust gases are a major factor in detectability of a helicopter performing air combat operations. In order to increase the combat effectiveness and survivability of military helicopters, several different types of the infrared suppressor (IRS) have been developed. This paper reviews contemporary developments in this discipline, with particular examples of the infrared signature suppression systems.

Open access
Manufacturing and Testing of Carbon Composite Samples Intended for Aviation

Abstract

The paper presents the manufacturing technology and quality control of samples made of composite materials intended, inter alia, for aircraft elements. The samples are made from carbon fiber reinforced prepreg in a polymer matrix which is commonly used in the aerospace industry. The authors described the dimensional requirements for samples made of composite materials for strength testing, and the main stages of production which have a direct impact on the quality of composite samples. Also presented is the technological process of producing flat carbon composite panels for composite samples, cutting the produced panels with a CNC plotter, cutting the samples on a conventional milling machine, and surface treatment of the samples on a surface grinder. The machining parameters that were experientially found to be optimal for the milling and grinding of carbon samples are specified as well. Finally, the method of quality control of the ready composite samples is described and solutions are presented to improve the production of high-quality samples.

Open access