Aircraft Structures

The object of research is a civil mainline aircraft with a transonic truss-braced wing. The problem of designing an aircraft of this scheme at the preliminary design stage is being solved in the work. The results of the work include the concept of designing aircraft with a transonic truss-braced wing, the main advantages of such a scheme, the process of determining the geometric parameters of the truss-braced, features of the preliminary design of an aircraft with an extremely high aspect ratio truss-braced wing, possible approaches to the arrangement of units and their mutual arrangement. The results are explained by the difference in the design model (the cantilever beam is replaced by a beam on two supports) in mass analysis and the increased wing aspect ratio in aerodynamic calculation. The final data are based on a statistical study to determine the basic geometric parameters of assemblies of modern mainline passenger aircraft, synthesis of parameters of analog aircraft. For example, an aircraft capable of carrying 250 passengers over a distance of 13.000 km is considered. In the design process, values of aspect ratio, taper ratio, wing area, vertical tail and horizontal tail area ratio, and fuselage dimensions are accepted. Drawings of the general appearance of the aircraft have been developed and, based on it, a master geometry of the theoretical contour has been constructed. Graphs of first-order polar and maximum lift-to-drag ratio have been plotted, the reduction of aerodynamic drag in percentage terms has been determined, and the increase in aerodynamic lift-todrag ratio in percentage terms for an aircraft with an extremely high aspect ratio truss-braced wing compared to similar characteristics of an aircraft with a conventional non-braced wing has been calculated. The approximate mass savings when using a truss-braced wing on the aircraft are determined in percentage terms. The expediency of using wings of greater aspect ratio, than modern aircraft currently have, has been justified. The expediency of using a brace for the aircraft with an extremely high aspect ratio wing has been justified. The obtained results can be used in practice in the process of developing the preliminary design of an aircraft with a truss-braced wing or in the modifications of existing aircraft to increase their fuel efficiency or increase the durability of wing elements due to reduced loads acting on them.

In an airline, each aircraft flying represents revenue, and each aircraft stuck on the ground represents operating costs. The company's operational efficiency depends on the constant mitigation of flight delays, and aircraft maintenance depends on Ground Support Equipment (GSE) to carry out its tasks. The number of maintenance bases increases with the increase in the number of destinations sold by the airline. This work introduces a quantitative method to relate different GSEs in different locations and consider the most significant impacts on flight delay. A case study was developed and applied to a large airline company, and 15 airports were considered, 13 in Brazil and 2 in Argentina. To this end, three major inputs of unstructured data were considered: (i) document analysis, (ii) interviews, and (iii) electronic forms. After the data processing stage, a statistical test was applied, which allowed for the identification of which aircraft maintenance bases required priority attention. The results of the correspondence analysis test differed from those of the descriptive statistics analysis, highlighting the importance of incorporating this test into the decision-making process. The company in this case study had set aside an amount of US$500,000 to improve productivity and reduce the number of flight delays. After the analysis and investigation stage, it was observed that 11 of the 17 most critical cases could be resolved with an investment of US$120,000, in the same way that the other cases could be resolved with the money in the budget. The results achieved demonstrated a contribution to theory by filling the identified gap, as well as a contribution to practice by presenting an additional method for decision-making to assist in the allocation of investments. Additionally, there are societal contributions made by relating these problems to flight delays.

An optimal sensor placement methodology is implemented and herein proposed for SHM model-assisted design and analysis purposes. The kernel of this approach analysis is a genetic-based algorithm providing the sensor network layout by optimizing the probability of detection (PoD) function while, in this preliminary phase, a classic strain energy approach is adopted as well established damage detection criteria. The layout of the sensor network is assessed with respect to its own capability of detection, parameterized through the PoD. A distributed fiber optic strain sensor is adopted in order to get dense information of the structural strain field. The overall methodology includes an original user-friendly graphical interface (GUI) that reduces the time-to-design costs needs. The proposed methodology is preliminarily validated for isotropic and anisotropic elements.

The objective of this work is to present a conceptual design and the modelling of a distributed sensor system based on fiber optic devices (Fiber Bragg Grating, FBG), aimed at measuring span-wise and chord-wise variations of an adaptive (morphing) trailing edge. The network is made of two different integrated solutions for revealing deformations of the reference morphing structure. Strains are confined to typical values along the span (length) but they are expected to overcome standard ranges along the chord (width), up to almost 10%. In this case, suitable architectures may introduce proper modulations to keep the measured deformation low while preserving the information content. In the current paper, the designed monitoring system combines the use of a span-wise fiber reinforced patch with a chord-wise sliding beam. The two elements make up a closed grid, allowing the reconstruction of the complete deformed shape under the acceptable assumption that the transformation refers to re...

In the framework of Clean Sky 2 Airgreen 2 GRA ITD project, this paper deals with the design process of a morphing winglet for a regional aircraft. By improving A/C aerodynamic efficiency in off-design flight conditions, the morphing winglet is expected to operate during long (cruise) and short (climb and descent) mission phases to reduce aircraft drag and optimize lift distribution, while providing augmented roll and yaw control capability. The mechanical system is designed to face different flight situations by a proper action on the movable parts represented by two independent and asynchronous control surfaces with variable camber and differential settings. A set of suitable electromechanical actuators are integrated within the limited space inside the winglet loft-line, capable of holding prescribed deflections for long time operations. Such a solution mitigates the risks associated with critical failure cases (jamming, loss of WL control) with beneficial impacts on A/C safety. Numerical details on the system architecture and ability to cope with the typical mission loads profiles are given, along with a description of the conceptual analysis and the expected system performance according to a suitable metric. 

In this study, flutter analyses are performed for generic adaptive camber wings with hingeless trailing edge control surfaces. These control surfaces operate based on a concept that exploits the controlled flexibility of the semi-open secondary wing structure. By introducing structural modifications that allow for chordwise sliding between upper and lower skin panels, positive or negative camber changes may be realized for the wing. Using MSC® PATRAN package, wing finite element models are created. In these models, components of the adaptive camber wing, i.e. front and rear spars, spar caps, skins, ribs, stringers and control bars are defined as separate property regions. In order to model the hingeless control surfaces, multi-point-constraints (MPC) are used to represent the sliding action, as well as the interactions between several components. In aeroelastic models created using MSC® FLDS, structural and aerodynamic degrees-of-freedom (dof) are coupled to each other using infinite plate spline functions. The unsteady aerodynamic loads are represented using the Doublet-Lattice Method (DLM). In numerical analyses performed, two different wing configurations are considered, namely Wings A and B. In Wing A, a single hingeless control surface extends throughout the full wing span. Wing B has the same structural properties as Wing A, except for the hingeless control surface, which is split into two equal sized parts. The results of the free vibration analyses show that for both wing configurations, the control surface motion is highly coupled to the bending and torsion type global modes. Furthermore, in the second configuration, additional local modes are observed for the control surface. As a final study, p-k method is employed to calculate flutter speeds for Wings A and B and to identify the modes of instability.

The Grumman X-29 was an American experimental aircraft that tested as Inverted-wing, canard control surfaces which is a wing configuration in which a small forewing is placed ahead of the main wing of the aircraft.In this paper we will try to study the stability and the aerodynamics of the x29 and we will focus on the wing.In this project i have done the modeling of the wing using CATIA V5 and the analysis in ANSYS and validation using XFLR5 and XFOIL.

Fuselage buckling of a stiffened composite cylinder is a very complex phenomenon that involves complex interactions between the skin and the stiffeners. Considering different configurations of the skin and stiffener, different types of buckling failure modes and failure loads are observed in stiffened cylinders. In this work failure modes and the buckling loads of stiffened composite cylinders under uniaxial loading condition is investigated by using analytical and experimental approaches. Initially, a developed model for buckling problem of an isogrid stiffened composite cylinder. In these models the stiffness contributions of the stiffeners is computed by analyzing the moment and force effect of the stiffener on the unit cell. The equivalent stiffness of the stiffener/shell panel is computed by superimposing the stiffness contribution of the stiffeners and the shell. Once the equivalent stiffness parameter is determined for the whole panel buckling load is calculated using the energy method. A 3-D finite-elements model was also built which takes into consideration the exact geometric configuration and the orthotropic properties of the stiffeners and the shell. Based on finite-elements model, a discussion is made on the different buckling failure modes observed. The results of these three types of analysis methods are compared and comments are made on the reliability of the analytical models developed and finally a parametric study was carried out and general conclusions were drawn regarding the optimum configurations of the different parameters of the grid-stiffened cylinder.

Drone aircrafts, also known as an Unmanned Aerial Vehicle (UAV) or Unmanned Aircraft Systems (UAS) has gained more importance in environmental monitoring as well as in telecommunication infrastructure theft response around the world. The study aims at identifying the type of sensors that can be mounted on drones for effective telecommunication infrastructure theft detection and prevention. The various parts of drone and configuration were tested. Sensors capable of detecting telecommunication infrastructures in the visible, infra-red, near infra-red, laser fluoro-sensor were all evaluated. The ability of the UAV to continuously and successfully patrol along or beside telecommunication infrastructure reveals that it takes about 5 minutes for the UAV to complete a programmed 150m autonomous patrol. During power test, result showed that for every 150m programmed patrol, 15 minutes of solar charging is required to restore the battery back to its initial voltage. It was concluded that a drone can properly be used for telecommunication infrastructure theft response operations. Appropriate sensors mounted on the drone can detect telecommunication infrastructure theft and can also access locations which are not readily accessible and other aerial patrol platform. The limitation of drones is the payload capability and its inability to operate well in windy weather since data collection with drone are faster, cheaper and easier during telecommunication infrastructure theft response operations. It is highly recommended to mount the suitable sensor capable of detecting telecommunication theft and vandalization even during nighttime operations.

Makalah ini membahas proses pembuatan pesawat model Chuck Glider (Outdoor Hand Launch Glider/OHLG) dengan menggunakan kayu balsa sebagai bahan utama. Penelitian ini bertujuan memberikan panduan teknis sekaligus menguji performa hasil rakitan melalui eksperimen sederhana berupa pengukuran waktu dan jarak luncur. Hasil menunjukkan bahwa desain yang akurat terhadap airfoil dan titik pusat gravitasi (CG) sangat memengaruhi kinerja terbang glider.

Unmanned aerial vehicles (UAV) have become ubiquitous in recent years due to their adaptability and ease of use. Surveillance UAVs in particular have seen increased interest and usage by law enforcement, civilian security, surveying, and federal services. The increased interest has led to the development of UAVs with increased endurance and payload capacity. Further as many of the applications of surveillance drones involve heightened security requirements, an aircraft of domestic make is preferential to many organizations. With this demand in mind, Inspired Products, LLC put forth a request for assistance in the design and testing of a surveillance UAV. More specifically, Inspired Products, LLC has mandated that the UAV be of a flying wing configuration in order to increase endurance. This flying wing UAV must be able to remain aloft for extended periods while also possessing a payload capacity which is sufficient to carry cameras and other sensory equipment. Additionally, the UAV ...

Flow and thrust calculations at supersonic speeds require intensive formulas and general assumptions, thus prolonging the preliminary design process. Today, the use of computer programs for aerodynamic design and analysis is inevitable in the development of aircraft. However, in this process, traditional calculation methods are mostly used. By performing the relevant calculations with a source code, time-consuming problems such as data extraction from tables, interpolation or calculation with formulas can be avoided. In this study, a computational tool was created in Python using the formulas contained in compressible flow theory. For the calculation, ISA (International Standard Atmosphere) and altitude values are first obtained from the user to determine the atmospheric conditions. These conditions are known to directly affect static conditions. Then, the data input of one of the selected parameters is made and the remaining parameters according to these input values are presented on the result screen together with the other outputs. These outputs were compared with NASA data and their accuracy was analysed. Two different configurations were created to examine the dependence of compressible flow calculations on atmospheric conditions. In the first one, constant ISA and different altitude values were analysed, while in the other one, constant altitude and different temperature deviations were evaluated. These evaluations revealed the sensitivity of the calculation results to atmospheric variables. The findings provide critical data on how to design and analyse aircraft under different operational conditions. This study, for the first time, provides calculations based on atmospheric variables, enabling them to efficiently obtain the values of parameters that depend on these data. This approach is an innovative contribution to the existing literature, expanding the body of knowledge on the analysis of compressible flows.

In the evolving domain of aerospace engineering, the need for optimized structures that balance weight, strength, and reliability is paramount. This paper investigates integrated methodologies that combine advanced structural analysis techniques and innovative design approaches tailored for both aircraft and spacecraft systems. Emphasis is placed on material optimization, computational methods, and failure prediction strategies. The study integrates historical perspectives with current innovations to project future possibilities for high-performance aerospace systems.

As more people travel by air, the aviation sector is feeling increased pressure to reduce its environmental impact. If sustainability becomes a part of aircraft management, efficiency in operations can be linked with protecting the environment. This document analyzes how aircraft companies can manage their fleets in a more sustainable way, using energy-saving technologies, arranging flights wisely and opting for environmentally friendly maintenance. Relying on advanced ways to analyze data, as well as using alternative fuels and more efficient logistics, these services are able to greatly reduce both their carbon footprint and any waste produced. Operators are using SAFs and electric or hybrid propulsion to keep their airlines profitable, as these approaches are needed to meet the strict guidelines set by authorities. Besides, when aircraft components are recycled and greener supply chains are used, the efficiency of resource use increases. To make progress, it is important to cooperate with agencies, manufacturers and airport authorities. The study also details how top aircraft management companies have included sustainability and achieved reductions in fuel usage and emission levels. Emphasizing sustainable actions, aircraft management providers contribute to worldwide efforts to manage climate change and gain an edge over other companies in the industry. The article stresses the need for urgent green practices and helps operators understand how to make their operations eco-friendly.

Morphing aircraft wings represent a transformative advancement in aerospace engineering, offering the ability to dynamically alter wing geometry in real time based on varying flight conditions. This capability enables substantial performance improvements across a wide range of flight regimes, including enhanced lift-to-drag ratios, increased maneuverability, optimized fuel efficiency, and better aerodynamic control. The potential benefits of morphing wings are far-reaching, impacting both military and commercial aviation by providing adaptive solutions that traditional fixed-wing designs cannot achieve. In recent decades, research in this area has transitioned from theoretical concepts to practical applications through the development of experimental platforms, advanced materials, and sophisticated control technologies. Pioneering programs such as NASA's Mission Adaptive Wing (MAW), DARPA's CRANE (Control of Revolutionary Aircraft with Novel Effectors), and Airbus's AlbatrossOne have showcased the feasibility and performance potential of morphing systems in real-world environments. The growing incorporation of morphing wing technologies in unmanned aerial vehicles (UAVs) and future air mobility vehicles further emphasizes the increasing readiness for widespread implementation. Despite these advances, significant challenges remain, including the need for scalable, durable smart materials, efficient actuation systems, reliable real-time control algorithms, and standardized certification procedures. Addressing these challenges requires cross-disciplinary collaboration in areas such as aerodynamics, materials science, structural engineering, control systems, and regulatory frameworks. Looking forward, innovations in soft robotics, artificial intelligence, and multifunctional composites will likely expedite the adoption of morphing wings, paving the way for more adaptable and sustainable aircraft designs in both military and civilian aviation.

In this study, analytical models considering different material and geometry for ‎both single and double-lap bolted joints were reviewed for better understand how to ‎select the proper model for a particular application. The survey indicades that the ‎analytic models selected for the adhesively single or double bolted lap joints, as well ‎as T, scarf, and stepped joints, with linear material properties are mostly two ‎dimensional and the studies on stress distribution and/or failure of the joint are ‎performed either experimentally, analytically or by finite element method. The results ‎seem to be generally accurate and adequate. Additionally, it was shown that any ‎increase in the bolt-hole clearance leads to an increase in bolt rotation, as well as a ‎decrease in bolt-hole contact area, and hence, a reduction in joint stiffness. Moreover, ‎studies on hybrid joints have revealed that the proper choice of adhesive material in ‎conjunction with bolts or rivets in a joint, allows for significant increase in the static ‎and fatigue strength compared to similar pure bonded joints. Additionally, the results ‎on hybrid scarf joints showed that it is vital to place fasteners closer to the ends of the ‎overlap to suppress the peak peeling stresses and hence, delay the effects of early ‎crack initiation in the adhesive layer...

Conductive nanofillers, such as carbon nanotube, graphene nanoplatelets, and carbon black particles (with diameters in nanometers) have been shown to enhance the electrical conductivity of fiber reinforced polymer matrix composites in many existing studies. The motivation is primarily for lightning strike protection, electromagnetic interference shielding, de-icing, and the manufacturing of lightweight electronic components. In this paper, we evaluate the lightning strike damage tolerance of carbon fiber reinforced polymer (CFRP) matrix composite laminates containing conductive nanofillers with varying weight fractions, including carbon black (CB), carbon nanotubes (CNT), and a mix of CB and CNT, through simulated lightning strike tests, followed by both non-destructive ultrasonic inspection and destructive sectioning to characterize the damage inflicted by the simulated lightning strike. Three-point flexural tests are performed to evaluate the residual strength retained by all CFRP specimens. Results show that lightning strike damage experienced varying levels of reduction for CFRP composite specimens containing conductive fillers in comparison to the baseline specimen without fillers. Notably, the delamination only penetrated to the interface between the 1st and 2nd layer for the specimen with 0.25 wt.% CNT in comparison to the baseline CFRP specimen for which the delamination penetrated to the interface between the 5th and 6th layer. Moreover, the retention of the flexural modulus increased from 26.5% to a maximum of 95.0% for the specimen with 0.25 wt.% hybrid CB and CNT. Yet, we show that using our chosen conductive fillers cannot fully eliminate lightning strike damage. Additionally, adding conductive fillers could compromise the flexural properties. We provide discussions on future recommendations on using conductive fillers for the lightning strike protection of CFRP composites.

The laboratory lightning testing commonly uses an indirect electrode as the current injection configuration to restraint the electrode jet for evaluation of lightning strike damage tolerance of aircraft materials. Such an indirect electrode configuration requires using a conductive ignition wire to initiate the arc. This work discusses the influence of added metal vapor, produced due to evaporation of the ignition wire, on the electric-arc-induced heat flux and current density as well as the material damage through numerical modeling and simulated experiments. Metal vapor originated from the requisite ignition wire considerably alters the net emission coefficient and transport properties of the arc, leading to questionable testing results and unreliable guidance for lightning protection design. The damage depth of an aluminum alloy is affected by 312.5% due to the changes in the net emission coefficient and thermal conductivity. The damage area shows moderate changes due to a Gaussian-shape decrease profile of heat flux and its insensitivity to the changes in the net emission coefficient. The direct electrode configuration is promising to avoid the use of ignition wire and produce material damage representative of actual damage caused by natural lightning. The results and discussions provide insights into the design of improved lightning certification tests.

In last decades, several research programs were founded worldwide to exploit the potentialities of the morphing concepts, especially to improve aerodynamic efficiency, and so reduce fuel consumption. Among these, the CRIAQ MDO-505 project represents the first joined research program between Canadian and Italian academies, research centers and leading industries. The aim of the project is to design, manufacture and tests in wind tunnel facilities a morphing wing tip for a Bombardier-type aircraft controlled by electric actuators and pressure sensors. In such framework, the authors intensively worked on the flutter clearance demonstration of the wind tunnel wing model equipped with a full-scale variable-camber aileron driven by load-bearing electro-mechanical actuators. Rational approaches were implemented in order to simulate the effects induced by variations of aileron actuator's stiffness on the aeroelastic behavior of the wing. Reliable models were properly implemented to enable fast aeroelastic analyses covering several configuration cases in order to prove clearance from any dynamic instability (flutter) up to 1.2 times the maximum flow speed expected during Wind Tunnel Tests. Finite-element models were properly developed in order to obtain and implement wing model modal parameters (modes shapes, frequencies, generalized masses, damping) in SANDY®, an in-house developed code, that was used for the definition of the coupled aerostructural model as well as for the solution of aeroelastic stability equations by means of theoretical modes association in frequency domain. Obtained results were finally arranged in a diagram showing trend of the flutter speed with respect to changes in control surface harmonic covering a wide range of values for the stiffness of the aileron (external) actuator. 

Nowadays, the design choices of the new generation aircraft are moving towards the research and development of innovative technologies, aimed at improving performance as well as to minimize the environmental impact. In the current "greening" context, the morphing structures represent a very attractive answer to such requirements: both aerodynamic and structural advantages are ensured in several flight conditions, safeguarding the fuel consumption at the same time. An aeronautical intelligent system is therefore the outcome of combining complex smart materials and structures, assuring the best functionality level in the flight envelope. The Adaptive Trailing Edge Device (ATED) is a sub-project inside SARISTU (Smart Intelligent Aircraft Structures), an L2 level project of the 7th EU Framework programme coordinated by Airbus, aimed at developing technologies for realizing a morphing wing extremity addressed to improve the general aircraft performance and to reduce the fuel burning up to 5%. This specific study, divided into design, manufacturing and testing phases, involved universities, research centers and leading industries of the European consortium. The paper deals with the aeroelastic impact assessment of a full-scale morphing wing trailing edge on a Large Aeroplanes category aircraft. The FE (Finite Element) model of the technology demonstrator, located in the aileron region and manufactured within the project, was referenced to for the extrapolation of the structural properties of the whole adaptive trailing edge device placed in its actual location in the outer wing. The input FE models were processed within MSC-Nastran ® environment to estimate stiffness and inertial distributions suitable to construct the aeroelastic stick-beam mock-up of the reference structure. Afterwards, a flutter analysis in simulated operative condition, have been carried out by means of Sandy ® , an in-house code, according to meet the safety requirements imposed by the applicable aviation regulations (paragraph 25.629, parts (a) and (b)-( )).

Power augmented ram (PAR) engine is a popular equipment to reduce the requirement of power for takeoff and improve aerodynamic performance. To provide detailed insight into the aerodynamic characteristics of wing-in-ground effect (WIG) craft with PAR engine, numerical simulations are carried out on WIG craft models in cruise. Simplified engine models are applied to the simulations. Two cruise modes for PAR engine are considered. The aerodynamic characteristics of the WIG craft and other features are studied. Comparisons with WIG craft model without PAR show that shutoff of PAR engine results in an increase in drag and less change in lift. Accordingly for the work of PAR engine, the air flow blown from the engineaccelerates the flow around the upper surface and a high-speed attached flow near the trailing edge is recorded. With the schemed PAR flow, more suction force is realized and the flow features over the wing vary noticeably. It is also shown that the Coanda effect, provided wi...

Summary The theory of torsion of thin walled beams of open cross-sections with influence of shear on the basis of the classical Vlasov’s theory of thin-walled beams of open cross-sections for beams with single and double symmetrical cross-sections is developed. It is proved that the beam subjected to torsion with influence of shear exerted by couples in the beam crosssections is also subjected to bending due to shear in the plane orthogonal to the plane of symmetry. The beam is subjected to torsion with influence of shear only in the case of double symmetrical cross-sections. The principal cross-section axes as well as the principal pole are defined according to the classical theory of thin-walled beams of open sections. Illustrative examples are given, as well as a comparison with the finite element method.

This paper analyses the lateral stability of tailless CAMAR-3 Unmanned Aerial Vehicle (UAV) when its tail fin (i.e. V-tail) is reconfigured to the wingtips. A tailless UAV may have longer endurance time, compared to the present configuration of V-tail. Nevertheless, a tailless UAV may experience reduction in lateral stability due to loss of yaw control surfaces. In the preliminary design of tailless-winglets UAV, semi-empirical method is applied to estimate the aerodynamic lateral stability derivatives, in order to investigate the stability of both configurations of UAV. A dynamic test rig based on pure yawing motion is built, to measure the lateral stability derivatives of  and  The time response data of pure yawing oscillation give the natural frequency and damping ratio that describe the aerodynamic derivatives as a result from wind-on and wind-off tunnel tests. The result indicates that UAV with either configurations are laterally stable. However, the tailless-winglets CAMAR has...

Stress analysis on a beam for hat cross-section with fixed ends was done. Only top and lower flanges were fixed without fixing the web, statically making the ends fixed. It was found that stress at edges was far superior to that at the middle for a uniformly distributed loaded beam. This paper presents a FEA study for reducing the stress at the beam ends by providing simple support along with fixed flanges. The simple support is provided at the lower flanges of hat cross-section beam. The support length was varied along the length of beam at both the ends. Optimized length of flange was found for minimized stress in the beam.

Foldable wing designs are becoming increasingly popular due to their advantages in the rapid deployment and compact packaging of fixed-wing UAVs, particularly when compared to horizontal take-off and VTOL counterparts. However, selecting an appropriate wing design requires the careful consideration of aerodynamic performance and volume storage constraints. As a result, a trade-off between performance and practicality must be addressed during the conceptual design phase. The primary objective of this study is to identify the optimal wing configuration for a tube-launched foldable wing design. To achieve this, the analysis combine an in-house design tool developed in Excel and XFLR5 v7.01 software.

Foldable wing designs are becoming increasingly popular due to their advantages in the rapid deployment and compact packaging of fixed-wing UAVs, particularly when compared to horizontal takeoff and VTOL counterparts. However, selecting an appropriate wing design requires the careful consideration of aerodynamic performance and volume storage constraints. As a result, a trade-off between performance and practicality must be addressed during the conceptual design phase. The primary objective of this study is to identify the optimal wing configuration for a tube-launched foldable wing design. To achieve this, the analysis combine an in-house design tool developed in Excel and XFLR5 v7.01 software.

Traditional aircraft designs rely on rigid wings with limited capabilities and adaptability. However, nature's flying creatures-birds, bats, and insects-achieve extraordinary agility and efficiency through dynamic wing morphing. This paper explores how bio-inspired origami mechanisms can revolutionize the field of aircraft wing design. By integrating folds which are inspired by avian wing structures and beetle elytra, we can demonstrate how morphing wings can improve manoeuvrability, fuel efficiency, and the overall performance in turbulent environments.

Within the fatigue evaluation of the EHlOl, Agusta has carried out a specific program of flaw tolerance evaluation of the primary loading path. The program is close to completion and this paper provides a summary of the most relevant results. For composite components, damage size was increased considering both manufacturing discrepancies greater than the minimum quality standard and impact damages clearly detectable during visual inspections. The favourable data achieved are based on the ‘no growth ’ concept. The metal parts of the main rotor head were evaluated by enhanced safe life method and fail safe capability. The slow crack growth approach was instead applied for the Rear Fuselage End Fittings, which connect the Tail Unit. All these evidences can be used in addition to the comprehensive safe life evaluation of the aircraft to improve the maintenance and the repair actions. Based on this experience, application of flaw tolerance criteria will be carried out on the new helicopt...

O processo de certificacao de producao conduzido pela Autoridade de Aviacao Civil (AAC), no Brasil representada pela ANAC, tem a finalidade de contribuir para a seguranca de voo por meio da verificacao da conformidade do Sistema de Gestao da Qualidade (SGQ) implementado com os requisitos de aeronavegabilidade exigidos nos regulamentos e manuais. Nao resta duvida que, nos ultimos anos, as certificacoes de terceira parte baseadas nas normas NBR ISO 9001, ou equivalentes do setor aeroespacial como, por exemplo, SAE AS 9100 e ABNT NBR 15100, trouxeram grande contribuicao para o setor. Neste contexto, torna-se fundamental que autoridades, fabricantes e certificadoras de terceira parte conhecam com mais detalhes o trabalho desenvolvido por cada um deles, seus diferentes propositos, formas de abordagens e como cada um pode contribuir para a melhoria do SGQ e, consequentemente, para a seguranca de voo. Este artigo tem a finalidade de nivelar conceitos de SGQ, certificacao e aeronavegabilida...

Power augmented ram (PAR) engine is a popular equipment to reduce the requirement of power for takeoff and improve aerodynamic performance. To provide detailed insight into the aerodynamic characteristics of wing-in-ground effect (WIG) craft with PAR engine, numerical simulations are carried out on WIG craft models in cruise. Simplified engine models are applied to the simulations. Two cruise modes for PAR engine are considered. The aerodynamic characteristics of the WIG craft and other features are studied. Comparisons with WIG craft model without PAR show that shutoff of PAR engine results in an increase in drag and less change in lift. Accordingly for the work of PAR engine, the air flow blown from the engineaccelerates the flow around the upper surface and a high-speed attached flow near the trailing edge is recorded. With the schemed PAR flow, more suction force is realized and the flow features over the wing vary noticeably. It is also shown that the Coanda effect, provided with an attached flow, introduces an appropriate and practical flow mode for WIG craft with PARengine in cruise. The results refresh our understanding on aerodynamic characteristics of WIG craft.

La caratterizzazione elettromagnetica del comportamento dinamico di elettrodi interrati, disperdenti elevate correnti impulsive, costituisce uno degli aspetti primari nella progettazione di un sistema di protezione dalle fulminazioni atmosferiche (LPS). D'altra parte, elevate correnti impulsive possono causare l'insorgere di fenomeni di ionizzazione del terreno, nelle zone prossime agli elettrodi interrati, nei punti in cui il campo elettrico totale supera il valore

The thickness of the adhesive has a major influence on the shear strength of bonded assemblies. This work is based on a study of the fatigue behavior of two cracked aluminum (2024 T351) plates repaired by patch (graphite/epoxy) under cyclic loading. For this we used a computer code to study the propagation of fatigue cracks to predict the life of the plates repaired named AFGROW. The first plate was repaired using an adhesive made from date palm waste whereas the second plate was repaired using FM-73 adhesive. The results obtained from this study show that, despite the low shear modulus of the adhesive made from date palm waste and the very low film thickness, the joint bonded with the latter gives good joint strength and a lifetime (number of cycles) similar to the joint bonded with the FM-73 adhesive when the thickness of the joint of the adhesive is greater than that of the adhesive made by the waste of the date palm. This shows that the strength of the bonded joint increases rapidly from very low thicknesses (less than a few hundredths of a millimeter). Finally, we recommend using the adhesive made from date palm waste for patch repair as well as for applications such as lightweight construction, electric vehicles or solar panels.

L'attuale filosofia di progetto per le strutture aeronautiche inizia a divenire troppo conservativa, soprattutto dopo l'introduzione di materiali più efficienti e avanzati strumenti di analisi. Per questo motivo il Progetto Europeo DAEDALOS si prefigge lo scopo di sviluppare nuovi competitivi metodi di progetto per la riduzione di peso strutturale, che potrebbe portare anche alla riduzione di emissioni degli aeroplani civili. L'obiettivo di questo lavoro di tesi, situata all'interno di questo progetto, è di determinare una base comparativa per quanto concerne i carichi dimensionanti dovuti alla turbolenza atmosferica (per il solo modello Discrete Gust Criterion), seguendo le tecniche di progetto correnti, al fine di valutare nuove metodologie. L'attività è focalizzata sulla generazione di modelli numerici strutturali e la definizione delle condizioni di carico dovute alla raffica atmosferica. I modelli ad elementi finiti degli impennaggi di un aereo civile (business jet) vengono definiti e utilizzati nel processo di riduzione; a questo scopo viene proposta una metodologia per ottenere le caratteristiche di rigidezza e massa equivalenti di un modello a trave e verificata con dei semplici modelli di trave. Successivamente il metodo di riduzione viene applicato agli impennaggi, generandone così i modelli a travi. Accanto alla filosofia di progetto attuale viene illustrata una soluzione alternativa, definita Upgraded Design Philosphy; non si tratta di un nuovo metodo, ma può essere la base per futuri sviluppi. Essa consiste nel condurre le analisi dinamiche direttamente su modelli strutturali ad elementi finiti di dettaglio o ibridi. Infine, le due procedure di progetto presentate sono applicate ai modelli del velivolo e confrontate in termini di risposta dinamica e livello di sforzo su componenti strutturali. I risultati hanno mostrato la validità della filosofia di progetto alternativa. Parole chiave: carichi di raffica, raffica discreta, processo di riduzione, filosofia di progetto, modello a travi, carichi dinamici

This paper contain the content of basic review of an aircraft fuel system .This paper cover the various fuel system and fuel subsystem used in aircraft .Purpose of an aircraft fuel Sub system to monitors the fuel supply, its control, storage, drainage and also maintain stability of aircraft.. Basically the purpose of fuel system is to supply the fuel in all phase of including landing ,takeoff, Banking and sharp maneuvering fuel system should also supply the sufficient amount of neat and clean fuel at required pressure. Types of fuel system may vary in aircraft but all the aircraft keeps their own fuel system. The fuel system must be used keeping the centre of gravity to be stable in mind.

Gulfstream was responsible for the engineering design, fabrication, and instrumentation of the Quiet Spike experiment. NASA provided the F-15B test aircraft, aircraft modification and maintenance, aircraft instrumentation, integration of the Quiet Spike and instrumentation with the aircraft system, engineering support for ground and flight tests, flight planning and operations, hazard analysis and risk mitigation, and control room monitoring of test flights. NASA also maintained airworthiness and flight safety responsibility throughout the program. The Air Force Flight Test Center was responsible for helping NASA DFRC obtain flight clearance for air refueling the Quiet Spike equipped F-15. The 46 th Test Group allowed Mr. Tom Hill to support NASA during near field shock wave probing flights as the pilot for the probing NF-15B aircraft. Boeing provided simulator support to NASA to explore aircraft stability and control boundary issues in preparation for the Quiet Spike test project. It is noteworthy that the Gulfstream-NASA team was fully integrated in the accomplishment of this test project. NASA was involved at a relatively early stage of the Quiet Spike hardware development effort at Gulfstream, which aided greatly in integrating the test article with the aircraft. Gulfstream maintained on-site representation at NASA throughout the aircraft modification and flight program.

Gulfstream Aerospace has long been interested in the development of an economically viable supersonic business jet (SBJ). A design requirement for such an aircraft is the ability for unrestricted supersonic flight over land. Although independent studies continue to substantiate that a market for a SBJ exists, regulatory and public acceptance challenges still remain for supersonic operation over land. The largest technical barrier to achieving this goal is sonic boom attenuation. Gulfstream's attention has been focused on fundamental research into sonic boom suppression for several years. This research was conducted in partnership with the NASA Aeronautics Research Mission Directorate (ARMD) supersonic airframe cruise efficiency technical challenge. The Quiet Spike, a multi-stage telescopic nose boom and a Gulfstream-patented design (references 1 and 2), was developed to address the sonic boom attenuation challenge and validate the technical feasibility of a morphing fuselage. Th...

In the field of linear elastic fracture mechanics, the fracture toughness is an important parameter for safe-life estimation of structural parts. The plane strain fracture toughness, KIc, is thickness independent and it can be obtained through the ASTM-E399 testing standards. The ASTM standards and procedures require detailed specimen preparation, pre-fatiguing the notch, and fatigue crack growth rate measurements. These tests are expensive and time consuming. Progressive failure analysis is therefore used to estimate material fracture toughness. This approach will combine finite element analysis (FEA) with a General Optimization Analysis (GENOA) software (1) to update material properties as damage occurs. The proposed approach will consider the static properties obtained from the stress-strain curve as an input to assess the crack tip stress and strain fields. The GENOA Progressive Failure Analysis (PFA) is based on material degradation concept throughout the FEA model as the load ...

Wing Warping and Its Impact on Aerodynamic Efficiency BEN LOH, JAMEY JACOB, Oklahoma State University -Inflatable wings have been demonstrated in many applications such as UAVs, airships, and missile stabilization surfaces. A major concern presented by the use of an inflatable wing has been the lack of traditional roll control surfaces. This leaves the designer with several options in order to have control about the roll axis. Since inflatable wings have a semiflexible structure, wing warping is the obvious solution to this problem. The current method is to attach servos and control linkages to external surface of the wing that results in variation of profile chamber and angle of attack from leading edge or trailing edge deflection. Designs using internal muscles will also be discussed. This creates a lift differential between the half-spans, resulting in a roll moment. The trailing edge on the other half-span can also be deflected in the opposite direction to increase the roll moment as well as to reduce roll-yaw coupling. Comparisons show that higher L/D ratios are possible than using traditional control surfaces. An additional benefit is the ability to perform symmetric warping to achieve optimum aerodynamic performance. Via warping alone, an arbitrary span can be warped such that it has the same aerodynamic characteristics as an elliptical planform. Comparisons between lifting line theory and test results will be presented.

The Eliminator is the answer to the need for an affordable, maintainable, survivable, high performance close air support aircraft primarily for the United States, but with possible export sales to foreign customers. The Eliminator is twin turbofan, fixed wing aircraft with high mounted canards and low mounted wings. It is designed for high subsonic cruise and an attack radius of 250 nautical miles. Primarily it would carry 20 500 pound bombs as its main ordnance , but is versatile enough to carry a variety of weapons configurations to perform several different types of missions. It carries state of the art navigation and targeting systems to deliver its payload with pinpoint precision and is designed for maximum survivability of the crew and aircraft for a safe return and quick turnaround. It can operate from fields as short as 1800 ft. with easy maintenance for dispersed operation during hostile situations. It is designed for exceptional maneuverability and could be used in a varie...

This paper examines the role of smart materials
in enhancing lightweight design for missiles, unmanned
aerial vehicles (UAVs), and commercial aircraft. Smart
materials, characterized by their ability to respond
dynamically to environmental stimuli, offer significant
advantages in aerospace applications by improving
performance, efficiency, and safety. The paper
categorizes various types of smart materials, including
shape memory alloys, electro active polymer and self
healing composites, highlighting their unique properties
and functionalities.
Applications across different aerospace domains are
explored, focusing on adaptive flight control, damage
tolerance, and energy efficiency in missiles and UAVs, as
well as fuel efficiency and passenger comfort in
commercial aircraft. The benefits of integrating smart
materials into aerospace designs are discussed,
emphasizing weight reduction, enhanced operational
capabilities, and long-term cost savings.
However, challenges such as manufacturing complexity,
cost implications, and regulatory hurdles must be
addressed for widespread adoption. The paper concludes
by identifying future research opportunities and trends in
sustainable
efficiency
and
operational
effectiveness. Their capabilities facilitate adaptive
designs that can dynamically adjust to changing
conditions, real-time damage detection systems that
enhance safety, and optimized energy consumption.
These advancements are particularly critical in both
military
and
commercial
aviation,
performance and reliability are paramount.
aviation
practices,
emphasizing the
transformative potential of smart materials in the
aerospace sector. Through this analysis, the study aims to
provide valuable insights into how smart materials can
revolutionize aircraft and missile design, leading to safer,
more efficient, and environmentally friendly aviation
solutions.

Modern helicopter propulsion relies critically on turboshaft engines, which have revolutionized rotorcraft capabilities through advances in power delivery and efficiency. This analysis examines the fundamental principles, recent technological innovations, and performance metrics that characterize contemporary turboshaft engines in helicopter applications. Computational modeling of the Brayton cycle highlights thermodynamic dynamics and provides key insights into improving design and operational efficiency.