Showing papers on "Landing gear published in 2007"

Magnetorheological landing gear: 1. A?design methodology

Abstract: Aircraft landing gears are subjected to a wide range of excitation conditions, which result in conflicting damping requirements. A novel solution to this problem is to implement semi-active damping using magnetorheological (MR) fluids. This paper presents a design methodology that enables an MR landing gear to be optimized, both in terms of its damping and magnetic circuit performance, whilst adhering to stringent packaging constraints. Such constraints are vital in landing gear, if MR technology is to be considered as feasible in commercial applications. The design approach focuses on the impact or landing phase of an aircraft's flight, where large variations in sink speed, angle of attack and aircraft mass makes an MR device potentially very attractive. In this study, an equivalent MR model of an existing aircraft landing gear is developed. This includes a dynamic model of an MR shock strut, which accounts for the effects of fluid compressibility. This is important in impulsive loading applications such as landing gear, as fluid compression will reduce device controllability. Using the model, numerical impact simulations are performed to illustrate the performance of the optimized MR shock strut, and hence the effectiveness of the proposed design methodology. Part 2 of this contribution focuses on experimental validation.

Magnetorheological landing gear: 2. Validation using experimental data

Abstract: Aircraft landing gears are subjected to a wide range of excitation conditions with conflicting damping requirements. A novel solution to this problem is to implement semi-active damping using magnetorheological (MR) fluids. In part 1 of this contribution, a methodology was developed that enables the geometry of a flow mode MR valve to be optimized within the constraints of an existing passive landing gear. The device was designed to be optimal in terms of its impact performance, which was demonstrated using numerical simulations of the complete landing gear system. To perform the simulations, assumptions were made regarding some of the parameters used in the MR shock strut model. In particular, the MR fluid's yield stress, viscosity, and bulk modulus properties were not known accurately. Therefore, the present contribution aims to validate these parameters experimentally, via the manufacture and testing of an MR shock strut. The gas exponent, which is used to model the shock strut's nonlinear stiffness, is also investigated. In general, it is shown that MR fluid property data at high shear rates are required in order to accurately predict performance prior to device manufacture. Furthermore, the study illustrates how fluid compressibility can have a significant influence on the device time constant, and hence on potential control strategies.

Airframe Noise Results from the QTD II Flight Test Program

Abstract: With continued growth in air travel, sensitivity to community noise intensifies and materializes in the form of increased monitoring, regulations, and restrictions. Accordingly, realization of quieter aircraft is imperative, albeit only achievable with reduction of both engine and airframe components of total aircraft noise. Model-scale airframe noise testing has aided in this pursuit; however, the results are somewhat limited due to lack of fidelity of model hardware, particularly in simulating full-scale landing gear. Moreover, simulation of true in-flight conditions is non-trivial if not infeasible. This paper reports on an investigation of full-scale landing gear noise measured as part of the 2005 Quiet Technology Demonstrator 2 (QTD2) flight test program. Conventional Boeing 777-300ER main landing gear were tested, along with two noise reduction concepts, namely a toboggan fairing and gear alignment with the local flow, both of which were down-selected from various other noise reduction devices evaluated in model-scale testing at Virginia Tech. The full-scale toboggan fairings were designed by Goodrich Aerostructures as add-on devices allowing for complete retraction of the main gear. The baseline-conventional gear, faired gear, and aligned gear were all evaluated with the high-lift system in the retracted position and deployed at various flap settings, all at engine idle power setting. Measurements were taken with flyover community noise microphones and a large aperture acoustic phased array, yielding far-field spectra, and localized sources (beamform maps). The results were utilized to evaluate qualitatively and quantitatively the merit of each noise reduction concept. Complete similarity between model-scale and full-scale noise reduction levels was not found and requires further investigation. Far-field spectra exhibited no noise reduction for both concepts across all angles and frequencies. Phased array beamform maps show inconclusive evidence of noise reduction at selective frequencies (1500 to 3000 Hz) but are otherwise in general agreement with the far-field spectra results (within measurement uncertainty).

Adaptive landing gear concept?feedback control validation

Abstract: The objective of this paper is to present an integrated feedback control concept for adaptive landing gears (ALG) and its experimental validation. Aeroplanes are subjected to high dynamic loads as a result of the impact during each landing. Classical landing gears, which are in common use, are designed in accordance with official regulations in a way that ensures the optimal energy dissipation for the critical (maximum) sink speed. The regulations were formulated in order to ensure the functional capability of the landing gears during an emergency landing. However, the landing gears, whose characteristics are optimized for these critical conditions, do not perform well under normal impact conditions. For that situation it is reasonable to introduce a system that would adapt the characteristics of the landing gears according to the sink speed of landing. The considered system assumes adaptation of the damping force generated by the landing gear, which would perform optimally in an emergency situation and would adapt itself for regular landings as well. This research covers the formulation and design of the control algorithms for an adaptive landing gear based on MR fluid, implementation of the algorithms on an FPGA platform and experimental verification on a lab-scale landing gear device. The main challenge of the research was to develop a control methodology that could operate effectively within 50 ms, which is assumed to be the total duration of the phenomenon. The control algorithm proposed in this research was able to control the energy dissipation process on the experimental stand.

Monitoring system for aircraft landing system

Abstract: A monitoring system for a landing gear system comprising a plurality of sensors for monitoring respective parameters of the aircraft landing system, and a monitor which receives the outputs of the sensors.

Landing gear for silent aircraft

Abstract: The Silent Aircraft Initiative aims to provide a conceptual design for a large passenger aircraft whose noise would be imperceptible above the background level outside an urban airfield. Landing gear noise presents a significant challenge to such an aircraft. 1/10th scale models have been examined with the aim of establishing a lower noise limit for large aircraft landing gear. Additionally, the landing gear has been included in an integrated design concept for the 'Silent' Aircraft. This work demonstrates the capabilities of the closed-section Markham wind tunnel and the installed phased microphone arrays for aerodynamic and acoustic measurements. Interpretation of acoustic data has been enhanced by use of the CLEAN algorithm to quantify noise levels in a repeatable way and to eliminate side lobes which result from the microphone array geometry. Results suggest that highly simplified landing gears containing only the main struts offer a 12dBA reduction from modern gear noise. Noise treatment of simplified landing gear with fairings offers a further reduction which appears to be limited by noise from the lower parts of the wheels. The importance of fine details and surface discontinuities for low noise design are also underlined.

Simulation model of an aircraft landing gear considering elastic properties of the shock absorber

Abstract: For the investigation of elastic bending of the landing gear shock absorber of an aircraft under dynamic loads upon landing and subsequent braking during roll out, an MBS-based model of the landing gear is introduced. To separate effects of the elastic bending of the main landing gear the fuselage is considered rigid. After performing a flare with subsequent landing, the aircraft is stopped by means of an antiskid system. For comparison, an analytical-numerical study of a finite-element model of the main landing gear shock strut components is done for simple static and dynamic loads considering Bernoulli's hypothesis. Simulation of a rough-landing manoeuvre reveals that vibrations due to the elastic properties of the shock absorber not only increase loads on the components but significantly affect the braking process as well.

Landing gear for a 'silent' aircraft

Abstract: The Silent Aircraft Initiative aims to provide a conceptual design for a large passenger aircraft whose noise would be imperceptible above the background level outside an urban airfield. Landing gear noise presents a significant challenge to such an aircraft. 1/10th scale models have been examined with the aim of establishing a lower noise limit for large aircraft landing gear. Additionally, the landing gear has been included in an integrated design concept for the 'Silent' Aircraft. This work demonstrates the capabilities of the closed-section Markham wind tunnel and the installed phased microphone arrays for aerodynamic and acoustic measurements. Interpretation of acoustic data has been enhanced by use of the CLEAN algorithm to quantify noise levels in a repeatable way and to eliminate side lobes which result from the microphone array geometry. Results suggest that highly simplified landing gears containing only the main struts offer a 12dBA reduction from modern gear noise. Noise treatment of simplified landing gear with fairings offers a further reduction which appears to be limited by noise from the lower parts of the wheels. The importance of fine details and surface discontinuities for low noise design are also underlined.

Storage compartment for the nose gear of an aircraft

Abstract: This storage compartment for the front landing gear is intended for an aircraft having a set of collapsible landing gears having a nose gear (4) centered on a longitudinal median plane of the fuselage (1). This storage compartment forms a sealed partition between a pressurized area and the housing of the nose gear in its collapsed position. It has a reinforced upper face having an area that is appreciably flat and appreciably horizontal when the aircraft is on the ground, so as to form a floor of a pressurized compartment of the aircraft.

Aircraft nose landing gear enclosure

Abstract: In one embodiment, an aircraft comprises a plurality of hoop frame support members and a landing gear enclosure comprising a curved surface. The plurality of support frame support members abut against and extend over the curved surface to provide support to the landing gear enclosure. In another embodiment, loads are transferred from a landing gear strut through a strut fitting, through at least one inner surface of the landing gear enclosure, through at least one outer surface of the landing gear enclosure, and into the plurality of hoop frame support members.

Screening of Potential Noise Control Devices at Virginia Tech for QTD II Flight Test

Abstract: In support of the QTD II (Quiet Technology Demonstrator) program, aeroacoustic measurements of a 26%-scale, Boeing 777 main landing gear model were conducted in the Virginia Tech Stability Tunnel. The objective of these measurements was to perform risk mitigation studies on noise control devices for a flight test performed at Glasgow, Montana in 2005. The noise control devices were designed to target the primary main gear noise sources as observed in several previous tests. To accomplish this task, devices to reduce noise were built using stereo lithography for landing gear components such as the brakes, the forward cable harness, the shock strut, the door/strut gap and the lower truck. The most promising device was down selected from test results. In subsequent stages, the initial design of the selected lower truck fairing was improved to account for all the implementation constraints encountered in the full-scale airplane. The redesigned truck fairing was then retested to assess the impact of the modifications on the noise reduction potential. From extensive acoustic measurements obtained using a 63-element microphone phased array, acoustic source maps and integrated spectra were generated in order to estimate the noise reduction achievable with each device.

Noise Control of Landing Gears Using Elastic Membrane-Based Fairings

Abstract: As part of a NASA contract started in 2002 intended to quantify and mitigate the noise emission of a 777 main landing gear, an innovative approach to noise control was developed and tested at Virginia Tech. The objective was to develop an alternative to conventional rigid fairings that would account for issues encountered in full scale implementation and constraints such as weight, dimensions, cost, maintainability, ease of inspection, and stowage, among others. After designing and testing several devices and materials, an innovative concept of making fairings from elastic cloth membranes was found to address most of the system constraints while providing significant noise reduction. As a result, a series of flexible fairings were developed to target the most dominant noise sources of a 26%-scale 777 main landing gear in terms of their contribution to the overall noise levels as determined from previous wind tunnel testing. In this manner, devices were designed for the strut, braces, lower truck, torque link and cable harness. These new fairing concepts were tested to demonstrate the potential noise benefits as well as to establish the feasibility of these devices for full-scale implementation. For this study, aeroacoustic measurements were performed using a 63-element microphone phased array. The results for the most promising devices are presented in the form of acoustic maps and reduction in the integrated spectra with respect to the baseline configuration. The effect of the fairing material on the noise reduction potential is also shown.

ANOPP Landing-Gear Noise Prediction with Comparison to Model-Scale Data

Abstract: The NASA Aircraft NOise Prediction Program (ANOPP) includes two methods for computing the noise from landing gear: the "Fink" method and the "Guo" method. Both methods have been predominately validated and used to predict full-scale landing gear noise. The two methods are compared, and their ability to predict the noise for model-scale landing gear is investigated. Predictions are made using both the Fink and Guo methods and compared to measured acoustic data obtained for a high-fidelity, 6.3%-scale, Boeing 777 main landing gear. A process is developed by which full-scale predictions can be scaled to compare with model-scale data. The measurements were obtained in the NASA Langley Quiet Flow Facility for a range of Mach numbers at a large number of observer polar (flyover) and azimuthal (sideline) observer angles. Spectra and contours of the measured sound pressure levels as a function of polar and azimuthal angle characterize the directivity of landing gear noise. Comparisons of predicted noise spectra and contours from each ANOPP method are made. Both methods predict comparable amplitudes and trends for the flyover locations, but deviate at the sideline locations. Neither method fully captures the measured noise directivity. The availability of these measured data provides the opportunity to further understand and advance noise prediction capabilities, particularly for noise directivity.

Flight command and direction on ground command system for an aircraft

Abstract: Aircraft flight control and ground steering control system This electrical flight control system is intended for an aircraft that has a main landing gear with a front landing gear. It is provided with a handle ( 2 ) that can move around two maneuvering axes ( 4, 6 ) by means of a linkage system ( 8 ), and is movable in rotation around a longitudinal axis substantially perpendicular to the maneuvering axes, means on each of the maneuvering axes for generating a pilot-operated instruction from a movement of the movable handle around one maneuvering axis, and means for generating an instruction in order to act on the orientation of the front landing gear of the aircraft as a function of the angular position of the movable handle ( 2 ) relative to the longitudinal axis.

Novel Pitch Control Effectors for a Blended Wing Body Airplane in Takeoff and Landing Configuration

Abstract: Since the beginning of flight with the Wright brothers, the shape of an airplane hasn’t really changed. An airplane has always been a fuselage with wings, a tail, engines and a landing gear. A couple of people, like the Horton brothers or Northrop, tried in the mid 30’s to completely change the airplane configuration with an innovative design of a tailless allwing airplane. However that concept was not consummated until the late 80’s when the B-2, the only flying wing to enter production to date, illustrated its benefits. Since then the airplane industry has attempted to adopt this design for future passenger airplanes because of its increased efficiency over a conventional tailed airplane. But there are some major challenges that must be resolved before one will see a Blended-Wing-Body (BWB) takeoff at a major International airport. One of the issues is its difficulty to rotate due to the missing tail. This paper presents a possible solution, namely the use of belly-flaps to enhance the lift and pitching moment during takeoff and landing. Wind tunnel tests on a generic BWBmodel have shown an increase up to 35% of the lift-off CL and an increase of 10% in pitching moment using belly-flaps mounted on the underside of the model.

QTD 2 (Quiet Technology Demonstrator 2) Main Landing Gear Noise Reduction Fairing Design and Analysis

Abstract: The advances in aircraft engine noise reduction and the increasing demand for quieter aircraft has led noise research to focus more attention on airframe noise. Landing gears and high lift systems have been known to significantly contribute to the total aircraft noise at approach idle conditions, especially in cases where high by-pass ratio engines are used, when noise from the engines is low enough that it could be considered comparable or lower than the noise from the airframe. Landing gears in service on today’s aircraft were not designed with noise impact in mind and contain a myriad of possible noise generating features. Today’s landing gear designer is challenged to consider noise among many other factors when designing efficient aircraft landing gear systems. It is a challenge further complicated if noise reduction solutions are required for retro-fit applications. Much of the experimental noise research conducted on landing system noise has centered around the understanding of noise generating mechanisms and evaluation of noise reduction concepts in model-scale environments such as wind tunnel tests. These experiments have provided valuable insight into landing gear noise sources. However, little effort has been made to integrate noise reduction research with full-scale landing gear design and evaluate noise reduction potential in a full-scale flight environment. The work conducted under the Quiet Technology Demonstrator 2 (QTD2) program marks a first step in the successful integration of noise research with landing gear design with the focus being to design, implement and evaluate noise reduction solutions in a full-scale flight environment. This paper discusses the design and analysis of a ‘toboggan’ shaped main landing gear noise reduction fairing for full-scale flight evaluation on a B777-300ER aircraft in the QTD 2 program. The fairing was selected for flight evaluation after a series of model-scale wind tunnel acoustic experiments were conducted in conjunction with full-scale feasibility studies. The fairing design addressed issues such as gear kinematics and stowing, brake cooling, ground operations and noise reduction potential. The design was supported by static stress analysis and flutter analysis to ensure that the fairing was flight worthy.

Shape Memory Alloy Based Smart Landing Gear for an Airship

Abstract: The design and development of a shape memory alloy based smart landing gear for aerospace vehicles is based on a13; novel design approach. The smart landing gear comprises a landing beam, an arch, and a superelastic nickeltitanium shape memory alloy element. This design is of a generic nature and is applicable to a certain class of light13; aerospace vehicles. In this paper a specixFB01;c case of the shape memory alloy based smart landing gear design and13; development applicable to a radio controlled semirigid airship (radio controlled blimp) of 320 m3 volume is13; presented.Ajudicious combination of carbon xFB01;ber reinforced plastic for the landing beam, cane (naturally occurring13; plant product) wrapped with carbon xFB01;ber reinforced plastic for the arch, and superelastic shape memory alloy is13; used in the development. An appropriate sizing of the arch and landing beam is arrived at to meet the dual requirement of low weight and high-energy dissipation while ndergoing x201C;large elasticx201D; (large nonlinear recoverable13; elastic strain) deformations to ensure soft landings when the airship impacts the ground. The soft landing is required13; to ensure that shock and vibration are minimized (to protect the sensitive payload). The inherently large energydissipating character of the superelastic shape memory alloy element in the tensile mode of deformation and the superior elastic bounce back features of the landing gear provide the ideal solution.Anonlinear analysis based on the classical and xFB01;nite element method approach is followed to analyze the structure. Necessary experiments and tests have been conducted to check the veracity of the design. Good correlation has been found between the analyses and testing. This exercise is intended to provide an alternate method of developing an efxFB01;cient landing gear with satisfactory geometry for a x201C;certain class of light aerospace vehiclesx201D; such as airships, rotorcraft, and other light unmanned air vehicles.

Requirements for RFID- based Sensor Integration in Landing Gear Monitoring - A Case Study

Abstract: Report Abstract: This case study aims at analysing the requirements for the integration of RFID and sensors in the integrated system health management process of aircraft landing gears. The study is based on a number of interviews and site visits at Messier-Dowty and Messier Services as well as on previous research conducted at the Cambridge Auto-ID Lab. The discussion, vision and the conclusions all aim at presenting the gathered requirements and the establishments for system design at a general level, hence the information about specific sensors and data requirements should be regarded as illustrative, realistic examples, not as an actual design specification.

Aeroacoustic Study of a 26%-Scale, High-Fidelity, Boeing 777 Main Landing Gear in a Semi-Anechoic-Wind-Tunnel Test Section

Abstract: Experiments were conducted on a 26%-scale high fidelity Boeing 777 main landing gear in the Virginia Tech (VT) Stability Wind Tunnel. This wind-tunnel was recently upgraded to a semi-anechoic facility, which allowed aeroacoustic measurements to be carried out in the far-field and in an environment with significantly less reflections. The model was a very faithful replica of the full-scale landing gear, designed to address the issues associated with low-fidelity models. A 63-element microphone phased array was used to locate the noise source components of the landing gear on the flyover path, both in the near- and far-field. The same landing gear model was previously tested in the original hard-walled configuration of the VT tunnel with the same phased array mounted on the wall of the test section, i.e. near-field position. The new anechoic configuration of the VT wind tunnel offered a unique opportunity to directly compare, using the same gear model and phased array instrumentation, data collected in hard-walled and semi-anechoic test sections. Through these tests some of the limitations associated with hard-walled wind tunnels were discussed. The tests also allowed the noise source components of the landing gear on the flyover path to be identified. It was shown that noise from the landing gear on the flyover path cannot be characterized by only taking phased array measurement straight under the gear.

Motorised airplane with mixed hydrodynamic and aerodynamic structure for take-off and landing on water, ground or snow

Abstract: A motorised airplane includes a landing gear (17) with at least two legs (21) capable of retracting into the fuselage (11) via hatches (28). A pair of hydrofoils (16) is fitted to the base of the fuselage (11) in conformance with the ailerons used for lift and hydrodynamic stability, directed towards the base like a reverse V shape. The legs (21) of the landing gear (17) are each articulated around the pivot axes (20), fitted onto the hydrofoils (16). The landing gear (17) is dual-function, using wheels (18) or skis (19) suspended on legs (21). Applications: airplane for landing on water, ground and snow.

Lateral Response of Nose-Wheel Landing Gear System to Ground-Induced Excitation

Abstract: Nose-wheel landing gears can become laterally unstable during takeoff, taxiing, and landing, exhibiting divergent coupled lateral flexural and torsional oscillations called shimmy. The system stability is governed by the gear and tire dynamic characteristics, system nonlinearities, and vibratory modes of the vehicle, as well as by the degree of coupling that exists between these modes. Ground unevenness can produce significant lateral excitation on the landing gear and results in adversely impacting its lateral stability. To evaluate a nose-wheel landing gear system for its stability and response, it is necessary to model system components to capture the contributions of the landing gear structure, the tire, wheel configuration, system nonlinearities, and its interaction with the runway. This paper examines the lateral response of linear and nonlinear simplified nose-wheel landing gear models to ground-induced lateral excitation. Considering torsional free play as the source ofnonlinearity and external excitation due to runway roughness, modeling and analysis of nose-wheel landing gear shimmy is presented. The spatial variation of the runway surface is modeled as a continuous profile, obtained as a combination of sinusoids to represent a randomlike ground-induced excitation with the specified power spectral density. Time-domain simulation studies on the linear landing gear system show that unacceptable levels of lateral accelerations may be caused even at subcritical velocities. Studies on nonlinear nose-wheel landing gear systems bring out the fact that the free play can result in a significant reduction of the critical shimmy velocity and the need for such simulations in the subcritical ranges of velocities.

Landing gear ground test

Abstract: A method of applying a test load to a landing gear mounted on an aircraft, the method comprising parking the aircraft with at least one tire of the landing gear on a platform; and moving the platform so as to apply the test load to the landing gear via the tire. An array of six platforms (30) is mounted on a sliding chassis (10) in a recessed oil bath (1). The platforms (30) can be independently rotated to apply torque. The spacing between the platforms can be adjusted to adapt for different landing gear configurations.

Modelling landing gear noise with installation effects

Abstract: This paper describes continued development and validation of a semi-empirical model of the aerodynamic noise generated by aircraft landing gears at approach. The model has been developed with Airbus funding over a number of years1,2 , but recent studies carried out as part of the EC funded SILENCER project have led to the introduction of a number of new effects that occur on aircraft in flight. The core of the noise model is based on nondimensional source spectra derived from a database of full-scale tests on landing gears installed in the DNW wind tunnel. The new installation effects have been derived using the results of small-scale model tests3 and by analysis of flight test data4. The model is used to examine differences between the performance of noise control fairings installed on a landing gear in a wind tunnel and similar fairings installed on a real aircraft in flight.

Noise sources control of an aircraft landing gear

Abstract: 3 Landing gears are one of the major sources of airfr ame noise at approach and previous studies have shown that fairings can be used succes sfully to reduce broadband noise radiation in the mid- and high-frequency ranges 1 . In flight tests 2,3 , however, the overall benefit of the fairings was offset by an increase i n low frequency broadband noise and a new tonal noise source that was believed to originate f rom the leg-door or hinge-door of the gear. This paper describes an experimental study on a 1/4 scale model of the main landing gear of the aircraft to control the low-frequency broadband noise and to identify and eliminate the source of the tone, whilst retaining the noise redu ction capability at higher frequencies. The aeroacoustic and aerodynamic characteristics of the model were assessed in a low-speed closed-loop wind tunnel using phased microphone arrays on the roof and wall of the tunnel and surface pressure transducers on the gear. The t one could be readily suppressed or reduced by a number of different treatments. Control of low frequency noise was less straightforward, although some preliminary solutions have been identified.

Hydraulic distributor for airplane landing gear

Abstract: A hydraulic distributor 10 assembles in a single body an assembly of hydraulic components that assure the supply of actuators for controlling the movements of the moving elements of an airplane landing gear, for which the movements of the landing-gear legs and of the trap-doors are assured by hydraulic actuators. The airplane includes two or more landing-gear systems, each including a distributor 10 with a single body. The body of each single-body distributor is advantageously created by removing unused parts from a body that can satisfy the needs of all of the landing-gear systems of an airplane, or by addition of extensions onto a minimal body that can satisfy the needs common to all of the landing-gear systems of the airplane.

Study of Belly-Flaps to Enhance Lift- and Pitching Moment Coefficient of a BWB-Airplane

Abstract: During the first century of flight few major changes have been made to the configuration of subsonic airplanes. A distinct fuselage with wings, a tail, engines and a landing gear persist as the dominant arrangement. During WWII some companies developed tailless all- wing airplanes. The concept failed to advance until 1953 when the British Avro Vulcan bomber appeared. This airplane matched, but did not exceed, the aero performance of it's conventional contemporary, the Boeing B-47. In the late 80's the B-2, became the only flying-wing to have entered major production in recent memory. It proved the benefits of all-wing designs, at least for a stealth platform. The advent of the Blended-Wing-Body addresses the historical shortcomings of all-wing designs, specifically poor volume utility, and excess wetted area as a result. The BWB is now poised to become the new paradigm for large subsonic airplanes. Major aerospace companies are studying the concept for next generation passenger airplanes. But there are still challenges. One is the Blended-Wing- Body's short control lever-arm in pitch. This affects rotation and go-around performance. This paper presents a possible solution by using a novel type of control surface, a belly-flap, on the under side of the wing to enhance its lift- and pitching moment coefficient during landing, go-around and takeoff. Increases of up to 30% in lift-off CL and 8% in positive pitching moment have been achieved during wind tunnel tests on a generic BWB-model with a belly-flap.

Front aircraft part comprising a flat partition between a pressurised zone and a non-pressurised zone housing landing gear

Abstract: The present invention relates to a front aircraft part (1) comprising a non-pressurised landing gear housing zone (28) designed to house a front landing gear (30) in a retracted state, as well as a pressurised zone (2) adjacent to the non-pressurised landing gear housing zone According to the invention, the pressurised zone is delimited by a set of walls among which only a substantially flat-shaped sealed partition wall (10) also participates in delimiting the non-pressurised landing gear housing zone (28)

The AIRBUS On-Ground Transport Aircraft Benchmark

Abstract: This chapter describes the behaviour of a transport aircraft and its systems during rolling. Notations and conventions are given first, followed by the main equations of motion. Loads affecting aircraft motion are then described and their modelling given. Finally a short aircraft behaviour analysis is provided. This chapter aims at offering the reader a clear understanding of the control application and its requirements.