Browse Topic: Aircraft tails
A 1/5th scale powered coaxial rotor and propeller system has been developed and tested in the National Full Scale Aerodynamic Complex (NFAC) 40x80 ft Wind Tunnel. Test conditions include airspeeds in excess of 250 kts, the highest recorded for a rotor in edgewise flight at the NFAC. The system was studied in four configurations: a powered coaxial rotor, a powered coaxial rotor with a propeller wake rake, a powered coaxial rotor with a powered propeller, and a bare hub rotor with a propeller wake rake. The high-quality data from the test included propeller, fuselage and main-rotor performance; aerodynamic-interactions between the rotors, fuselage, empennage, and propeller; acoustics and handling-qualities attributes. These results have been used to validate physics-based rotorcraft modeling tools and enhance the quality of full-scale X2 Technology® aircraft designs. Innovative solutions to test measurement challenges included rotor shaft strain gages, balance thermal control systems
Additive manufacturing presents a promising approach to aerospace component design, thanks to its ability to create intricate geometries that contribute to weight reduction. While numerous efforts have been made to 3D print aerospace parts, their application in helicopter gearboxes remains limited due to the critical nature of these components. This paper explores the design process behind manufacturing a fatigue-critical housing for a helicopter tail gearbox. Specifically, it highlights the design constraints that prompted the adoption of an innovative manufacturing technique in the aerospace sector. Additionally, it examines the methodology used to meet these constraints and details the optimized final geometries achieved through the design process. Finally, results from manufacturing trials and fatigue testing are reported.
The empennage of a helicopter is largely responsible for its stability in forward flight. Its performance is mainly determined by its aerodynamics. In this paper, the empennage of a CoAX 2D ultralight research helicopter is analyzed in detail. For this purpose, the helicopter was equipped with flow measurement devices and flight tests were performed, covering different flight conditions. Measurements from a nose boom as well as the pilot’s control inputs and helicopter's position are available for evaluation. For the empennage in particular, seven-hole flow probes were mounted on it and various cameras were used to record the movement of the surface tufts.
Rotor hub parasite drag remains one of the challenges in further improving the forward-flight capabilities of coaxial rotorcraft. Comprehensive datasets on notional coaxial hub configurations are rare, and more so at Reynolds numbers sufficiently high to preserve dominating flow structures downstream into the wake where they interact with the rotorcraft empennage and tail. The present investigation was designed specifically to improve the understanding of interactional aerodynamics effects and wake flow physics of counter-rotating coaxial rotor hubs. A unique dataset is presented on a rotor hub design equipped with the DBLN 526 airfoil at a diameter-based Reynolds number of 1.13x106, corresponding to approximately quarter-scale Reynolds conditions of a coaxial compound helicopter at 200 knots. The experiments measured the time-averaged and time-varying drag on the hub configuration, with focus on a cruise advance ratio of 0.25 and a high-speed condition at 0.60. In addition to
Heavy class attack helicopter development program aims to develop a new generation assault helicopter with high weapon capacity and modern combat technologies. Design requirements lead to a complicated aerodynamic shape. Wind tunnel tests gain importance for validation of aerodynamic design decisions and methodologies. A short test campaign is planned in a high Reynolds number environment which is achieved through pressurization. Generation of aerodynamic characteristics, effect of under-wing stores, effectivity of tail surfaces and main rotor hub interactions construct the base of test plan. Tests are conducted under varying pressure and airspeed combinations starting from 1.1 Bar 100 m/s to 3 Bar 85 m/s. Test results are compared with CFD simulations as a part of validation studies. Reynolds Averaged Navier-Stokes Simulations provide satisfactory results. Improved results are obtained with high fidelity turbulence model, wall modeled very large eddy simulations.
The term “3 inch ice shapes” has assumed numerous definitions throughout the years. At times it has been used to generally characterize large glaze ice accretions on the major aerodynamic surfaces (wing, horizontal stabilizer, vertical stabilizer) for evaluating aerodynamic performance and handling qualities after a prolonged icing encounter. It has also been used as a more direct criterion while determining or enforcing sectional ice shape characteristics such as the maximum pinnacle height. It is the authors’ observation that over the years, the interpretation and application of this term has evolved and is now broadly misunderstood. Compounding the situation is, at present, a seemingly contradictory set of guidance among (and even within) the various international regulatory agencies resulting in an ambiguous set of expectations for design and certification specialists. The focus of this paper is to provide a more complete and accurate historical accounting of “3 inch ice shapes
This document describes a practical system for a user to determine observer-to-aircraft distances. These observer-to-aircraft distances can be either closest point of approach (CPA) distances during field measurements or overhead distances during acoustic certification tests. The system uses a digital camera to record an image of the subject aircraft. A method of using commercial software to obtain the distance from such an image is presented. Potential issues which may affect accuracy are discussed.
This SAE Aerospace Recommended Practice (ARP) provides processes for achieving the required cleanliness standards during the fabrication, assembly, and functional test of aircraft hydraulic systems. It covers exclusion and removal of solid and liquid contaminants from tubing during manufacture and final assembly, flushing of the installed system, and final checks to ensure cleanliness requirements are met.
This aerospace information report (AIR) provides historical design information for various aircraft landing gear and actuation/control systems that may be useful in the design of future systems for similar applications. It presents the basic characteristics, hardware descriptions, functional schematics, and discussions of the actuation mechanisms, controls, and alternate release systems. The report is divided into two basic sections: 1 Landing gear actuation system history from 1876 to the present. This section provides an overview and the defining examples that demonstrate the evolution of landing gear actuation systems to the present day. 2 This section of the report provides an in depth review of various aircraft. A summary table of aircraft detail contained within this section is provided in paragraph 4.1. The intent is to add new and old aircraft retraction/extension systems to this AIR as the data becomes available. NOTES 1 For some aircraft, the description is incomplete, due to
To increase the cruising range for VTOL aircraft it has become necessary to add a wing or wings so the aircraft can vertically take off like a helicopter but cruise like an airplane. This paper compares the aerodynamic efficiency, stability, and handling qualities of four different cruise configurations: conventional wing-tail airplane, canard airplane, flying wing and tandem wing. An additional aim is to perform a parametric study of the tandem wing aircraft configuration because that has become a popular choice among eVTOL aircraft designers. This paper does not examine the hovering flight portion of the mission. The study is carried out using a vortex lattice model and a RANS CFD model. The paper reveals the pros and cons of each configuration in terms of aerodynamics and flight mechanics. The parametric study of the tandem wing illustrates the effect of parameters such as the relative wing sizes and wingspan on the performance of a tandem wing aircraft. The paper also shows
This paper presents the identification and verification of a six degrees-of-freedom (6-DOF) flight dynamics model of a hybrid-lift (buoyancy and propulsive lift) multicopter unmanned aerial vehicle using the frequency-domain system identification technique. The hybrid-lift flight vehicle of interest was a dynamically representative (by z-axis CB vs CG location and Buoyancy Ratio) 29% hub-to-hub scale prototype of a full-scale vehicle designed for multi-use operations with a maximum payload of 250 lbs. From the system identification process, it was concluded that stable roll and pitch dynamics can be expected from a hybrid-lift multicopter configuration designed with high Buoyancy Ratio (BR) and a stabilizing buoyant restoring moment. This dynamic behavior is uniquely different from standard multicopters, which exhibit extremely unstable dynamics in those axes. Additionally, from the heavily attenuated yawaxis dynamic control response, it was concluded that a vertical tail or other yaw
This SAE Aerospace Information Report (AIR) covers the field of civilian, commercial and military airplanes and helicopters. This summary of tail bumper design approaches may be used by design personnel as a reference and guide for future airplanes and helicopters that require tail bumpers. Those described herein will consist of simple rub strips, structural loops with a wear surface for runway contact, retractable installations with replaceable shock absorbers and wear surfaces and complicated retractable tail landing gears with shock strut, wheels and tires. The information will be presented as a general description of the installation, its components and their functions.
This SAE Aerospace Information Report (AIR) covers the field of civilian, commercial and military airplanes and helicopters. This summary of tail bumper design approaches may be used by design personnel as a reference and guide for future airplanes and helicopters that require tail bumpers. Those described herein will consist of simple rub strips, structural loops with a wear surface for runway contact, retractable installations with replaceable shock absorbers and wear surfaces and complicated retractable tail landing gears with shock strut, wheels and tires. The information will be presented as a general description of the installation, its components and their functions.
A modular vertical takeoff and landing (VTOL) unmanned aerial system (UAS) is made up of multiple unmanned aerial vehicle (UAV) modules with uniform wingtips for tip-to-tip docking. Each UAV has twin booms with front and rear propellers and an empennage with a downward-mounted vertical rudder. All the propellers are tiltable for VTOL and the front ones are stowable for cruise efficiency.
T-tail configurations are a promising approach to increase vertical tail efficiency, reduce fuselage download and hub load cycle amplitudes in low speed transition. However, the horizontal tail can be subject to rotor wake impingement in cruise flight which might lead to high dynamic loads and structural fatigue. The involved aerodynamics are in addition highly complex and hence difficult to be predicted by simulation. In this work a simulation approach for empennage structural loads and vibration prediction is established based on free-wake analysis and modal fuselage approximation, focusing on the expectedly most dominant aerodynamic interaction effects at the T-tail. The results are compared to flight test data to evaluate the approach, and sensitivities of the framework are assessed. The results indicate that the motion of the horizontal tail is characterized only by a few modeshapes, predominantly driven by rotor wake influence, rather than rotor loads via the structural load path
An aeroelastic coupling framework is applied to the UH-60A platform to examine aerodynamic-induced vibrations at four advance ratios spanning the flight envelope. Both one-way and two-way aeroelastic coupling results are examined at each condition. The two-way coupled results are observed to generally predict closer values to measured flight test data on the lifting surfaces of the empennage, and a less pronounced effect is seen in stiffer, nonlifting structure. The effect of aeroelastic coupling subiterations is examined, and they are found to further refine the two-way coupled results, generally improving prediction quality.
Robust and accurate predictions of rotorcraft aerodynamic and structural loads and vibrations are essential for designing advanced rotorcraft. The aerodynamic environment around the rotors is nonlinear and unsteady, the rotor and its wake interact strongly with fuselage and empennage to drive the structural vibrations. All of the components are elastic structures linked with one another by structural and aerodynamic interactions requiring a high fidelity coupled analysis. This paper presents simulations and validations for two examples: the aerodynamic interactions of a powered rotor - fuselage - empennage wind tunnel model using CFD (Computational Fluid Dynamics), and the structural loads and vibrations of a flight test aircraft using coupled CFD/CSD (Computational Structural Dynamics) - FEA (Finite Element Analysis). The NASTRAN FEA generated an elastic fuselage modal model which was coupled to the CFD/CSD tools in the CREATETM-AV HELIOS framework. The interactional aerodynamics
The intent of this document is to provide recommended practices for conducting shock absorption testing of civil aircraft landing gear equipped with oleo-pneumatic shock absorbers. The primary focus is for Part 25 aircraft, but differences for Part 23, 27, and 29 aircraft are provided where appropriate.
The Inconel 718 is an alloy based on nickel of high thermal and mechanical resistance, which allows its wide application in the aerospace industry, being generally implemented in aircraft tail cone and engine components. On the other hand, these features become a recurring problem when the machining of this material is performed. For example, in the drilling process of this superalloy, the cutting tools used exhibit excessive wear due to the high temperature and pressure at the cutting edge. However, there are numerous parameters that can influence the cutting tool life, and when analyzed and well defined, determine the types of modifications needed to enable less wear, and consequently an increase of its useful life in service. Given this context and knowing that the study of tool life in the Inconel 718 drilling process is extremely relevant in the aerospace sector, this paper presents a wear study in order to evaluate the behavior of different types of cutting tools used to drill
In efforts to increase the accuracy and reliability of altimetry, speed measurement and other aspects of air data, a great deal of attention and money have been expended on new and refined pressure transducing and computing systems and on the standards by which they are calibrated. So much progress has been made in this that the limiting factor is, or may soon be, the sensing and transmitting in the aircraft of the pressures to be transduced. Until the appearance of References 1-13 and 18 there was little guidance available on the maintenance of pitot and static systems. This report presents what information is available, suggests limits, and lists the principal original papers on the subject.
A CFD simulation methodology for the inclusion of the post-impact trajectories of splashing/bouncing Supercooled Large Droplets (SLDs) and film detachment is introduced and validated. Several scenarios are tested to demonstrate how different parameters affect the simulations. Including re-injecting droplet flows due to splashing/bouncing and film detachment has a significant effect on the accuracy of the validations shown in the article. Validation results demonstrate very good agreement with the experimental data. This approach is then applied to a full-scale twin-engine turboprop to compute water impingement on the wings and the empennage. Since the performance characteristics of twin-engine commercial turboprops are such that they operate most efficiently at flight levels where SLD encounters may occur, the goal of this article is to establish a 3D computational methodology to eventually enable a complete study of the impact of FAR 25 Appendix O on the IPS requirements for this
The rotor hub asembly is a primary contributor to rotorcraft parasite drag. Reducing hub drag is one mandatory step to enabling future high - sped conventional and compound rotorcraft. The importance of high - Reynolds number testing of rotor hub flows is emphasized by realizing that high - Reynolds number turbulent coherent structures remain strong for long distances downstream up to the long - age wake where they interact with the empennage and tail. Basic research conducted through the Vertical Lift Research Center of Excellence (VLRCOE) at Pen State's water tunnel facilities has provided unique high Reynolds - scale data of rotor hub wakes, providing new data for physical understanding and validation of computa tional fluid dynamics (CFD) methods. A first rot or hub flow prediction workshop was held in June 2016; the present paper focuses on 'blind comparison results' between experimental data and CFD analyses that were part of the second rotor hub flow prediction workshop at Pen
Aerodynamic interactions between the rotor and the empennage can have a significant impact on steady and unsteady loads and often result in challenges in a rotorcraft design phase. In the present work, numerical analysis of rotor-empennage aerodynamic interactions were compared to full-scale flight test data with respect to steady and unsteady interactional aerodynamic effects. The flight tests provided loads for a low-empennage and a T-Tail configuration for various forward flight velocities. For the T-Tail configuration, additional pressure sensors provided validation data for steady and unsteady interaction effects. The numerical analysis was focused on an unsteady panel method, complemented by high-fidelity CFD/CSM-coupling results for a level flight state. Furthermore, a supplemental validation of the unsteady panel method was performed against an isolated wing-vortex interaction experiment. The flight test data revealed a strong asymmetry in mean empennage loads, which increases
This SAE Aerospace Recommended Practice (ARP) establishes requirements for the function, characteristics, and installation of an aircraft On Board Weight and Balance System (OBWBS) for use on civil transport aircraft. This document is not intended to specify design methods, mechanisms, or material to accomplish the requirements set forth.
The challenge of increasing range and speed of a rotorcraft is encountered in the scope of the European CleanSky2 "Fast Rotorcraft" project by Airbus Helicopters with the compound helicopter design RACER (RapidAndCostEfficientRotorcraft) for which the box wing and the tail parts designs are respectively protected by patent. This paper presents the DLR contributions to the RACER development. This includes the aerodynamic design of the wing and tail section as well as an overall assessment of performance and noise. In a first step the aerodynamic properties of the configuration are evaluated both isolated and with consideration of the main rotor and lateral rotor interferences by the use of actuator discs. In the second step, the investigated possibilities to improve the configurations performance are described. These include airfoil design for improved high lift performance of the wing and tail section, an optimization of the box wing circulation distribution on the upper and lower wing
Within the framework of NACOR project in CleanSky 2 AIRFRAME ITD, ONERA and DLR performed parallel investigations dealing with the RACER high-speed demonstrator, and especially with its tail parts, each partner respectively focusing on vertical fins (ONERA) and horizontal stabilizer (DLR). During this design phase, most of the CFD simulations were steady-state and neglected the effect of the rotor (or rotor-head) and of the propellers. It however turned out that the rotor-head had a significant effect on the vertical fins and that it was essential to take into account its rotation in time-accurate simulations: the wake from the rotor-head, the upper deck and the engine cowlings indeed strongly impacts the left vertical fin because of the clockwise rotation of the rotor-head. It induces strong oscillations on the tail unit loads, and the mean tail unit lateral thrust is also significantly increased. Moreover the main conclusions of this 'aerodynamic interactions' investigation are
Accurate prediction of aeroelastic coupling between rotor wake and structure remains a key challenge to the development of advanced rotorcraft. Limitations of existing analysis tools to predict such aeroelastic interactions, notably empennage buffeting effects, have resulted in costly late-cycle design changes in multiple rotorcraft development programs, including the UH-60A and AH-64A. Aeromechanical phenomena involving interactions of the fuselage and rotor wake are complex, interdisciplinary, and three-dimensional in nature. For this reason, full vehicle CFD/CSD coupled analysis is essential to accurately capture the mutually dependent interactions between the aerodynamic loads and the aeroelastic response associated with these phenomena. The current state-of-the-art in rotorcraft analysis involves CFD/CSD coupled analysis of aeroelastic rotors and wings, but rigid representations of the fuselage and empennage structures (Ref. 1). To address this limitation, an elastic fuselage
Multi-objective optimization of horizontal tail of a conventional rotor helicopter is achieved using a genetic algorithm, which is coupled with comprehensive analysis tools, Flightlab® and in-house rotorcraft simulation tool TAI Originated Rotorcraft Simulation (TOROS). Genetic algorithm is used to design a tail that improves static longitudinal stability characteristics of the helicopter during autorotation as well as its longitudinal dynamic stability characteristics at high speeds. Another optimization target is to minimize pitch attitude change in transition to forward flight while keeping pitch attitude close to zero at 140 knots in cruise. This study shows a framework of horizontal stabilizer optimization over its aerodynamic lift characteristics, which can be altered either by introducing gurney flaps and/or slats to change lift characteristics, vortex generators (turbulators) to postpone flow separation or simply by changing incidence angle. By solving a multi-objective
The US Army's Aviation Development Directorate (ADD) has successfully collaborated with its industry partners to reduce system parasitic weight for aviation platforms through multifunctional structures technology development. In short, this can be generalized as achieving weight savings by replacing the combination of aircraft structure and an independent, add-on mission enabler with a singular system that performs the functions of both structure and mission enabler. This extensive multifunctional technology development for aviation structural applications has yielded significant weight savings over parasitic designs. Technologies demonstrating this structural multifunctionality for weight reduction include integrally armored helicopter floor, lightweight integrally armored helicopter floor, lightning-protected structure, structural antenna aperture, helicopter empennage antenna structure, combat tempered aft fuselage, blast attenuating aircraft structure, and highly durable floor
Within the framework of NACOR project in CleanSky 2 AIRFRAME ITD, ONERA and DLR performed parallel investigations dealing with the RACER high-speed demonstrator, and especially with its tail parts, each partner respectively focusing on vertical fins (ONERA) and horizontal stabilizer (DLR). The present paper focuses on ONERA's contribution to the rear part design: both new vertical fins and design recommendations have been provided based on a multi-fidelity approach. A large panel of performance assessment tools, shape modification and optimization strategies have indeed been used. A major shape modification of the vertical fin has first been proposed in order to tackle a flow separation issue. An optimization process then resulted in an optimized vertical fin aerodynamic design, which met all the constraints and achieved all the objectives. This strong cooperation between ONERA and Airbus Helicopters enabled this investigation to be successful, leading the final vertical fins protected
Fabrication and assembly of the majority of control surfaces for Boeing’s 777X airplane is completed at the Boeing Defense, Space and Security (BDS) site in St. Louis, Missouri. The former 777 airplane has been revamped to compete with affordability goals and contentious markets requiring cost-effective production technologies with high maturity and reliability. With tens of thousands of fasteners per shipset, the tasks of drilling, countersinking, hole inspection, and temporary fastener installation are automated. Additionally and wherever possible, blueprint fasteners are automatically installed. Initial production is supported by four (4) Electroimpact robotic systems embedded into a pulse-line production system requiring strategic processing and safeguarding solutions to manage several key layout, build and product flow constraints. Commonality amongst the robots was desired to allow each to effectively address any of the commodities which range from small fairings to very large
Wind tunnel tests have been conducted to support development of the SB>1 DEFIANT™ Joint Multi-Role Technology Demonstrator. The objective is to provide data to validate and enhance the aerodynamic performance and flight dynamics models and to improve understanding of the aerodynamics of X2 TECHNOLOGY™ configurations. The first model was a 1/11 scale airframe with a powered propeller that was tested in the United Technologies Research Center (UTRC) Pilot Wind Tunnel (PWT) in 2013-2014. The second model was a 1/5 scale airframe with a powered coaxial main rotor that was tested at the U.S. Air Force National Full Scale Aerodynamic Complex (NFAC) in 2016. This model could also be tested with a powered propeller. Measurements included forces and moments on the various components, as well as fuselage, empennage, and blade surface pressures. For the 1/11 model, fuselage-induced flow fields at the propeller and empennage locations were also measured. Application of the experimental results to
Aircraft manufacturers are seeking automated systems capable of positioning large structural components with a positional accuracy of ±0.25mm. Previous attempts at using coordinated arm robots for such applications have suffered from the use of low accuracy robots and minimal systems integration. Electroimpact has designed a system that leverages our patented Accurate Robot technology to create an extensively automated and comprehensively integrated process driven by the native airplane component geometry. The predominantly auto-generated programs are executed on a single Siemens CNC that controls two Electroimpact-enhanced Kuka 6 axis robots. This paper documents the system design including the specification, applicable technologies, descriptions of system components, and the comprehensive system integration. The first use of this system will be the accurate assembly of production empennage panels for the Boeing 777X, 787 and 777 airplanes.
In the following work a set of CFD computational cases was calculated in order to obtain the aerodynamic characteristics of I-28 gyroplane in a wide range of sideslip angle. Severe modifications were checked out, and most important on the directional stability components of forces and moments, acting on an airframe, have been shown in aerodynamic coefficient form. A part of these calculations was to test the influence of rudder deflection on baseline gyroplane aerodynamic properties. In order to compare the results with already flying example of gyroplane, with known, good flight characteristics, a geometry was reconstructed with low accuracy, but enough to obtain reasonable sideslip characteristics, especially for high sideslip angle.
A model-scale wind tunnel test was conducted to determine propulsive efficiency and relative vibration levels of a tail mounted propeller in the wake of a powered rotor and generic fuselage. Six-component propeller loads were measured for all test points with a focus on thrust and torque. Propeller and main rotor operating conditions were set to mimic low- and highspeed vehicle flight operations, simulating speeds from 105 kts to 200 kts. A total pressure wake survey conducted without the propeller installed was used to determine the propeller plane inflow characteristics. Propeller operation had no measureable effect on rotor trim whereas the main rotor states significantly altered the propeller performance. All propeller positions showed a propulsive efficiency increase relative to the isolated propeller data when operated in the rotor wake. No position showed noticeable vibration levels higher or lower than another. The highest propulsive efficiency was measured for the mid-height
This paper presents an efficient and high fidelity aerodynamic interaction modeling method for effective simulation and analysis of compound rotorcraft as well as aircraft configured with multiple rotors. The methodology is the first-principle based viscous Vortex Particle Method (VPM) whose rotor wake modeling accuracy has been validated through extensive simulation. This research extends the modeling methodology to address modern multiple rotor systems and compound rotorcraft and emphasizes the mutual interaction between the rotors, wings, fuselage, and aerodynamic surfaces of a full rotorcraft. The developed methodology aims to provide an effective modeling tool to support the design and analysis of next generation vertical lift vehicles. In this paper, the mutual aerodynamic interaction between major components of modern rotorcraft configurations (such as the rotor/rotor, the rotor/wing, the rotor/propeller, the rotor/empennage, and interactions) and its impact on the vehicle
Conventional aircraft typically include propulsion engines that are under the wing or tail surfaces. Each propulsion engine system includes an engine housed in a nacelle with an inlet and a nozzle system. Primary component noise sources from the engine system include the noise associated with the fan, compressor, turbine, and combustor, and the noise associated with the high-velocity jet exhaust flow. There are many methods for reducing the various noise sources from the aircraft, including those noise sources from the engine system. One method includes the use of the aircraft itself as an acoustic shield for the noise sources associated with the engines. This approach requires a new configuration of aircraft with the engines installed on the upper surface of the wing or fuselage, or an aircraft that has a hybrid wing and fuselage. Of the engine noise sources, the jet exhaust is a particular challenge due to the fact that the noise sources are in the exhaust flow itself, and therefore
In comparison with traditional aircraft design, the configuration design phase of a hybrid buoyant aircraft is quite complex due to the augmentation of aerostatic and aerodynamic lift. The first step in assessing the optimal configuration for such aircraft is to approach the design in a number of different ways with different shapes of hull and diversed empennage arrangements. Concept selection methods like Pugh concept selection charts can assist to rank the population of different concepts of such aircraft. In the present work, an effort was done to explore the potential usage of Pugh's method in a comprehensive manner and to establish a basis for choosing a particular design concept. Driving factors of such design concepts were reviewed alongwith the selection of figure of merits, which were further evaluated by taking Megalifter as a reference with which all other configurations under consideration were compared. The initial set of concept generation was obtained on some initial
The intent of this paper is to provide a general overview of the main engineering and test activities conducted in order to support A350XWB Ice and Rain Protection Systems certification. Several means of compliance have been used to demonstrate compliance with applicable Certification Basis (CS 25 at Amendment 8 + CS 25.795 at Amendment 9, FAR 25 up to Amendment 129) and Environmental protection requirements. The EASA Type Certificate for the A350XWB was received the 30th September 2014 after 7 years of development and verification that the design performs as required, with five A350XWB test aircraft accumulating more than 2600 flight test hours and over 600 flights. The flight tests were performed in dry air and measured natural icing conditions to demonstrate the performance of all ice and rain protection systems and to support the compliance demonstration with CS 25.1419 and CS25.21g. Prior to the flight test campaign, extensive engineering analyses, laboratory tests and system
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