141 results on '"Tailplane"'
Search Results
102. Control law reconfiguration using robust linear parameter varying control
- Author
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J. Mulder, Samir Bennani, R. van der Sluis, and G. Schram
- Subjects
Linear parameter-varying control ,Tailplane ,Adaptive control ,Elevator ,Control theory ,law ,Computer science ,Control system ,Autopilot ,Control reconfiguration ,Control engineering ,Robust control ,law.invention - Abstract
Introduction An alternative approach to fault-tolerant control is introduced by implementation of Robust Linear Parameter Varying (LPV) Control. As illustration an aircraft control problem is considered, in which the tailplane is assumed to suffer from degraded control effectiveness. The changing tailplane control effectiveness is modelled by scaling the input to the tailplane actuator. A Robust LPV controller is designed that achieves the desired performance objectives for all degradation levels, while maintaining robustness to system uncertainties. Several failure scenario’s have been studied by means of. nonlinear simulations, to show that the proposed control technique provides stability to all possible parameter variations and is successful in achieving predefined performance specifications. *Assistant Professor, Control and Simulation Division, Faculty of Aerospace Engineering. tMSc. Student, Control and Simulation Division, Faculty of Aerospace Engineering. SResearch Engineer, SKF Engineering & Research Centre, Nieuwegein, The Netherlands. §Professor, Chairman of Control and Simulation Division, Faculty of Aerospace Engineering. Member AIAA. Copyright 01999 by the American Institute of Aeronautics and Astronautics, ,Inc. All rights reserved. Aviation exists by favour of sufficient safety. With the estimated growth of the volume of passengers and flights, which could very well triple between now and 2014, it is necessary to improve the level of safety in aviation. An important remark in this context is that there will always be a form of risk involved in flying. It is not the question how this risk can be avoided, but how this risk can be managed 3. If risk is managed properly, safety levels in aviation can be improved. Fault-tolerant control (FTC) is one way to manage risk in safety-critical systems, like aircraft. FTC has the objective of providing desirableperformance and stability in presence of. uncertainties, like system faults, in order to enable safe (termination of) operation. It can be applied to improve s stem reliability, maintainability and survivability 1% . In recent years several FTC research projects have been carried out. In 1 the Multiple Model Adaptive .Control approach (MMAC) is proposed. In MMAC, for different failure types a controller mode is derived before hand. Each failure hypothesis corresponds to one model and one control mode. The model that has the highest likelihood is selected together with’the corresponding control mode. (c)l999 American Institute of Aeronautics & Astronautics or published with permission of author(s) and/or author(s)’ sponsoring organization. In I2 a fuzzy logic app roach is suggested. Just like in the MMAC approach for each failure hypothesis one model and control mode is used. Through the use of fuzzy measures that indicate the failure state, interpolation between the failure modes and control modes is achieved. l1 introduces a H, Model Matching approach for Propulsion Controlled Aircraft (PCA) design. The aircraft with multiple control surface failure, will be controlled by fly-by-throttle control only. An H, controller is synthesized, such that by dynamic compensation the actuated crippled aircraft and the nominal control-surface-actuated aircraft model match optimally in the H, sense. The PCA control problem emerged from the Sioux City accident in which a DC-10 lost all of its hydraulics and the crew managed to crash land the aircraft using engine thrust only. In 1977 a Lockheed L-1011 experienced an elevator failure and pitch control was regained by using differential thrust. NASA Dryden Flight Research Center developed conventional propulsion control schemes and flight tested a propulsion control system for the F-15 and the MD-11 8. In 7 a reconfigurable flight control approach is presented, which is based on a dynamic inversion control law in an explicit model following framework. The results presented in that paper, are based on work on the RESTORE program. The purpose of the program is to develop a reconfigurableladaptive control design methodology and algorithms for a class of year 2000+ low signature fighter aircraft possessing little or no vertical control surface effecters. Very important work, concerning stability analysis of reconfigurable and gain-scheduled flight control systems, is .presented in 16. Stability Analysis methods using Linear Matrix Inequalities (LMIs) are developed and applied to systems with timevarying scheduling parameters. This paper proposes an alternative integration of Autopilot design and Control Law Reconfiguration by implementation of a Robust Linear Parameter Varying (LPV) Controller in order to provide fault tolerance to an aircraft suffering from degraded tailplane control effectivity. To illustrate the potentials of Robust LPV Control, an aircraft control problem is considered in which the change of tailplane control effectivity is modelled by scaling the input to the tailplane actuator. Linear Matrix Inequalities (LMIs)lO are set up for controller synthesis and stability analysis. A D/K-like iteration, similar to ,o-synthesis 2, is performed to synthesize a Robust LPV controller, without ruining the essential convexity of the LMIs 13. The paper is structured as follows. First the LPV approach used in this paper is reviewed 6~ 13. The approach is illustrated on the Research Civil Air’ craft Model (RCAM) g. Starting from the nonlinear equations of motion, an uncertain LPV system is derived and design specifications are defined and translated into suitable weighting functions 5. The controller synthesis interconnection, resulting from these steps, forms the basis for the proposed D/Klike iteration, resulting in a Robust LPV controller. In first instance ,u-synthesis and p-analysis 2 are performed for frozen parameters to get an indication of the performance level that can be ideally obtained. Next, the obtained local results are compared with the global result, obtained with Robust LPV control. Finally, the Robust LPV controller is validated through nonlinear simulations for a set of predefined failure scenario%. more...
- Published
- 1999
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103. In-flight aerodynamic measurements of an iced horizontal tailplane
- Author
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Judith Foss VanZante and Thomas P. Ratvasky
- Subjects
Aircraft flight mechanics ,Engineering ,Tailplane ,Elevator ,business.industry ,Angle of attack ,Longitudinal static stability ,Stall (fluid mechanics) ,Flight control surfaces ,Aerospace engineering ,business ,Marine engineering ,Slip (aerodynamics) - Abstract
The effects of tailplane icing on aircraft dynamics and tailplane aerodynamics were investigated using, NASA's modified DHC-6 Twin Otter icing research aircraft. This flight program was a major element of the four-year NASA/FAA research program that also included icing wind tunnel testing, dry-air aerodynamic wind tunnel testing, and analytical code development. Flight tests were conducted to obtain aircraft dynamics and tailplane aerodynamics of the DHC-6 with four tailplane leading-edge configurations. These configurations included a clean (baseline) and three different artificial ice shapes. Quasi-steady and various dynamic flight maneuvers were performed over the full range of angles of attack and wing flap settings with each iced tailplane configuration. This paper presents results from the quasi-steady state flight conditions and describes the range of flow fields at the horizontal tailplane, the aeroperformance effect of various ice shapes on tailplane lift and elevator hinge moment, and suggests three paths that can lead toward ice-contaminated tailplane stall. It was found that wing, flap deflection was the most significant factor in driving the tailplane angle of attack toward alpha(tail stall). However, within a given flap setting, an increase in airspeed also drove the tailplane angle of attack toward alpha(tail stall). Moreover, increasing engine thrust setting also pushed the tailplane to critical performance limits, which resulted in premature tailplane stall. more...
- Published
- 1999
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104. NASA/FAA Tailplane Icing Program overview
- Author
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Thomas P. Ratvasky, James T. Riley, and Judith F. Van Zante
- Subjects
Engineering ,Ice formation ,Tailplane ,Code development ,Aeronautics ,business.industry ,Aerodynamics ,business ,Wind tunnel ,Icing - Abstract
The effects of tailplane icing were investigated in a four-year NASA/FAA Tailplane Icing, Program (TIP). This research program was developed to improve the understanding, of iced tailplane aeroperformance and aircraft aerodynamics, and to develop design and training aides to help reduce the number of incidents and accidents caused by tailplane icing. To do this, the TIP was constructed with elements that included icing, wind tunnel testing, dry-air aerodynamic wind tunnel testing, flight tests, and analytical code development. This paper provides an overview of the entire program demonstrating the interconnectivity of the program elements and reports on current accomplishments. more...
- Published
- 1999
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105. Investigation of dynamic flight maneuvers with an iced tailplane
- Author
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Thomas P. Ratvasky and Judith F. Van Zante
- Subjects
Engineering ,Leading edge ,Tailplane ,Elevator ,Aeronautics ,business.industry ,Deflection (engineering) ,Flapping ,Stall (fluid mechanics) ,business ,Stabilizer (aeronautics) ,Icing - Abstract
A detailed analysis of two of the dynamic maneuvers, the pushover and elevator doublet, from the NASA/FAA Tailplane Icing Program are discussed. For this series of flight tests, artificial ice shapes were attached to the leading edge of the horizontal stabilizer of the NASA Lewis Research Center icing aircraft, a DHC-6 Twin Otter. The purpose of these tests was to learn more about ice-contaminated tailplane stall (ICTS), the known cause of 16 accidents resulting in 139 fatalities. The pushover has been employed by the FAA, JAA and Transport Canada for tailplane icing certification. This research analyzes the pushover and reports on the maneuver performance degradation due to ice shape severity and flap deflection. A repeatability analysis suggests tolerances for meeting the required targets of the maneuver. A second maneuver, the elevator doublet, is also studied. more...
- Published
- 1999
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106. Improvement of a Preliminary Design and Optimization Program for the Evaluation of Future Aircraft Projects
- Author
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R. Seubert and D. Strohmeyer
- Subjects
Engineering ,Wing ,Tailplane ,Higher-Order Panel Method ,Lift-induced drag ,business.industry ,Megaliner ,Aerodynamics ,MDO ,HISSS ,Code Calibration ,Design studies ,Drag ,Supersonic Commercial Transport Aircraft ,Multidisciplinary Design And Optimization ,Supersonic speed ,Integrated Aircraft Preliminary Design ,Three Surface Aircraft ,Canard ,Aerospace engineering ,Reduction (mathematics) ,business ,TSA ,Design Code PrADO ,SCT - Abstract
The improvement of an integrated aircraft predesign code and its application to future aircraft concepts is reported. For the simulation of a Megaliner canard configuration as well as a supersonic commercial transport aircraft (SCT) the predesign code PrADO was extended by the higher-order panel method HISSS. The improvement of the aerodynamic model allows the simulation of interference effects between wing, tailplane and canard as well as the extension of the simulated flight regime to supersonic speeds. The application of the calibrated predesign code to a Megaliner configuration leads to differences between published and predicted design weights below 6%. Preliminary results of the simulation of a canard configuration show that a canard may not automatically increase the aerodynamic efficiency L/D. A reduction of the induced drag is overcompensated by an increase of the minimum drag due to additional friction drag of the canard. The SCT design studies also provide converged solutions, however, a redesign of the Concorde shows significant discrepancies with respect to the operational empty weight, fields for future investigations. more...
- Published
- 1998
107. Conducting artificial tailplane icing evaluations at the Air Force Flight Test Center
- Author
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Russell Ashenden
- Subjects
Engineering ,Tailplane ,Aeronautics ,business.industry ,Center (algebra and category theory) ,Aerospace engineering ,business ,Flight test ,Icing - Published
- 1995
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108. Future STOVL flight control: development of two-inceptor trimmap based pitch plane control law for the VAAC research aircraft
- Author
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S.J. Andrews, B.W. Rawnsley, and G.W. D'Mello
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Attitude control ,Engineering ,Tailplane ,business.industry ,Plane (geometry) ,Law ,Nozzle ,Development (differential geometry) ,Aerospace engineering ,business ,Optimal control ,Throttle ,Thrust vectoring - Abstract
STOVL aircraft have several force "motivators" controlling the pitch plane. These include tailplane angle, flap position, throttle and nozzle angle. Future configurations are likely to have these motivators, possibly adding other new features such as independent nozzle thrust vectoring, and canard foreplanes. The trimmap based pitch plane control law, known as Control Law 001, is a solution to the major challenge of optimally controlling these many motivators with just two pilot inceptors. This paper describes design, development and initial flight trials of the VAAC 001 control law. more...
- Published
- 1994
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109. Ice-induced tailplane stall - The problems and some operational solutions
- Author
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John Dow and Porter Perkins
- Subjects
Tailplane ,Environmental science ,Stall (fluid mechanics) ,Marine engineering - Published
- 1993
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110. Aerodynamic Interference Issues in Aircraft Directional Control.
- Author
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Nicolosi, Fabrizio, Vecchia, Pierluigi Della, and Ciliberti, Danilo
- Subjects
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INTERFERENCE (Aerodynamics) , *AIRPLANE steering gear , *DEFLECTION (Mechanics) , *COMPUTATIONAL fluid dynamics , *ELEVATORS (Airplanes) - Abstract
This work investigates the aerodynamic interference among airplane components caused by rudder deflection for a typical turboprop aircraft geometry through the computational fluid dynamics technique. At no sideslip, an airplane is in symmetric flight conditions. The rudder deflection creates a local sideslip angle close to the vertical tailplane, and this effect is increased by fuselage and horizontal tail. Typical semiempirical methods, such as United States Air Force Stability and Control Data Compendium (USAF DATCOM), do not take into account for these effects, proposing the same corrective parameters both for pure sideslip and rudder deflection conditions. Numerical analyses executed on several aircraft configurations with different wing and horizontal tailplane positions show that the interference factors are smaller than those predicted by the USAF DATCOM procedure, providing guidelines for a more accurate aircraft directional control analysis and hence rudder preliminary design. [ABSTRACT FROM AUTHOR] more...
- Published
- 2015
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111. Sailplane Design: Design Elements, Aerodynamics, Static and Dynamic Stability Calculations, CS22 and OSTIV Rules, Air Loads on Wing, Fuselage and Tailplane, Static Tests and Flight Test, Calculation Examples V. Pajno Macchione Editore, via Salvo D'Acquisto 2, 21100 Varese, Italy. 2006. 455pp. Illustrated. Euros 51.50. ISBN 88-8340-274-X
- Author
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Howard Torode
- Subjects
Engineering ,Wing ,Tailplane ,biology ,business.industry ,Aerospace Engineering ,Design elements and principles ,Euros ,Aerodynamics ,Structural engineering ,biology.organism_classification ,Stability (probability) ,Flight test ,Fuselage ,business - Published
- 2009
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112. Lastenreduktion an Großflugzeugen durch aktive Bedämpfung der Koplanarbewegung des Höhenleitwerks (Load Alleviation for Large Aeroplanes by Active Mode Control of the Coplanar Motion of the Horizontal Tailplane)
- Author
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H.-D. Joos, Ch. Ballauf, and M. Kordt
- Subjects
Engineering ,Tailplane ,Control and Systems Engineering ,Control theory ,business.industry ,Active mode ,Electrical and Electronic Engineering ,business ,Motion (physics) ,Computer Science Applications - Abstract
Die Finite–Element–Analyse der Struktur von Großflugzeugen zeigt eine oder mehrere Eigenmoden des Höhenleitwerks im Frequenzbereich von 2–4 Hz, die Koplanar–Mode(n) genannt werden. Die zugehörigen Eigenformen beschreiben eine antimetrische, koplanare, vorwärts–rückwärts Bewegung des Höhenleitwerks. In Folge der niedrigen Eigenfrequenzen können diese Schwingungen leicht durch seitliche Böeneinwirkung angeregt werden, insbesondere durch Einwirkung von Turbulenzen am Seitenleitwerk. Bedingt durch die geringe aerodynamische Dämpfung dieser Schwingungen entstehen starke Resonanzen, die hohe Strukturlasten im Bereich des Anschlusses des Höhenleitwerks verursachen. Mit einem System zur aktiven Bedämpfung der Schwingungen durch eine Rückführung der Beschleunigung in x–Richtung an der Spitze des Höhenleitwerks auf den Seitenruderausschlag kann eine Reduktion der Strukturlasten um mehr als 20% erzielt werden. more...
- Published
- 2002
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113. Aerodynamic parameters estimated from flight and wind tunnel data
- Author
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Vladislav Klein and James G. Batterson
- Subjects
business.product_category ,Tailplane ,Angle of attack ,business.industry ,Directional stability ,Aerospace Engineering ,Aerodynamics ,Stabilator ,Airplane ,Physics::Popular Physics ,Range (aeronautics) ,Environmental science ,Aerospace engineering ,business ,Physics::Atmospheric and Oceanic Physics ,Wind tunnel - Abstract
A procedure for determination of aerodynamic model structure and estimation of aerodynamic parameters is applied to data from a modern fighter operating within an angle of attack range of 5-60 deg. The paper briefly describes the airplane, available flight and wind tunnel data, postulated models for airplane aerodynamic coefficients, and flight data analysis. The results presented contain only a small number of selected longitudinal and lateral parameters. These parameters were obtained from various maneuvers and subsets of joined data from several flights. The estimated parameters are in good agreement with the wind tunnel measurements. The resulting aerodynamic model equations seem to be satisfactory for the prediction of airplane motion. more...
- Published
- 1986
- Full Text
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114. An analytical study of the induced drag of canard-wing-tail aircraft configurations with various levels of static stability
- Author
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G. F. Butler
- Subjects
Materials science ,Tailplane ,Wing ,Lift-induced drag ,Longitudinal static stability ,Aerospace Engineering ,Trimming ,Mechanics ,High lift - Abstract
SummaryThe prospect of reducing the induced drag of an aircraft by using both a canard and tailplane for trimming is investigated and results are compared with those for conventional tail-aft and canard arrangements. It is concluded that improvements of approximately 20% in lift-drag ratio are theoretically possible at high lift coefficients by the use of an additional trimming surface. more...
- Published
- 1983
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115. A finite element study of harmonic wave propagation in periodic structures
- Author
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Ruth M. Orris and Maurice Petyt
- Subjects
Tailplane ,Acoustics and Ultrasonics ,Mechanical Engineering ,Imaginary part ,Mathematical analysis ,Structure (category theory) ,Condensed Matter Physics ,Finite element study ,Vibration ,Mechanics of Materials ,Finite element technique ,Propagation constant ,Beam (structure) ,Mathematics - Abstract
The vibration behaviour of periodic structures may be described by a characteristic “propagation constant”. The natural frequencies of the finite periodic structure are related to the variation of the purely imaginary part of this propagation constant, known as the phase constant. A method is presented for using the finite element technique to evaluate the phase constant of an arbitrary periodic structure. The method is applied to two types of periodic construction. The first is a periodically supported infinite beam. The second is a skin rib structure, with dimensions typical of a tailplane. Two models of the tailplane are considered, a beam model and a plate model. more...
- Published
- 1974
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116. Lifting-Surface Theory for an Oscillating T-Tail
- Author
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Koji Isogai
- Subjects
Physics ,Aerodynamic force ,Tailplane ,Lifting-line theory ,Incompressible flow ,Mathematical analysis ,Coordinate system ,Aerospace Engineering ,Flutter ,Integral equation ,T-tail - Abstract
A lifting-surface theory for predicting aerodynamic forces on an oscillating T-tail is presented with special reference to the effects of tailplane dihedral and tailplane incidence. The analysis is confined to the incompressible flow case. By introducing a new coordinate system oscillating coincidentally with the in-plane motion of the tailplane and by employing a perturbation technique, the boundary-value problems are derived. The integral equations for the prediction of the antisymmetric load distributions on the tailplane, which are induced by the in-plane motion of the tailplane, are derived from the second-order boundary-value problem, while the first-order problems are those of conventional lifting-surface theories. A method for solving the integral equations is proposed and the working forms of them are given. Some numerical examples for simplified T-tails are given and compared with the experimental results. The theory is useful for predicting the effects of tailplane dihedral and tailplane incidence on the flutter speed of a T-tail. more...
- Published
- 1974
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117. Noise shielding for aircraft
- Author
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E.G. Broadbent
- Subjects
Physics ,Noise ,Tailplane ,Aircraft noise ,Mechanics of Materials ,Mechanical Engineering ,Acoustics ,Electromagnetic shielding ,Airframe ,Aerospace Engineering ,Shielding effect ,Trailing edge ,Acoustic attenuation - Abstract
To reduce the noise nuisance of aircraft, consideration is sometimes given to shielding the engines from the ground by means of the aircraft wings and tailplane. Methods of calculating the shielding effect are reviewed. Allowance for refraction by the flowfield on the basis of ray theory is also discussed, as is the special problem of the wing trailing edge where noise may be generated by interaction both with acoustic sources and with jet flow. more...
- Published
- 1976
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118. The longitudinal dynamic stability and control of a large receiver aircraft during air-to-air refuelling
- Author
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K. A. M. Ali, V. Trochalidis, and A. W. Bloy
- Subjects
Tailplane ,Elevator ,business.industry ,Separation (aeronautics) ,Longitudinal static stability ,Aerospace Engineering ,Mechanics ,Structural engineering ,Downwash ,Range (aeronautics) ,Horseshoe vortex ,Environmental science ,Vertical displacement ,business - Abstract
SummaryThe longitudinal stability and control of a large receiver aircraft was considered during air-to-air refuelling. A simple horseshoe vortex was used to model the tanker wake and approximate expressions were derived for the additional aerodynamic derivatives due to the position and attitude of the receiver aircraft within the downwash field. These derivatives were shown to depend on the mean variation of downwash with vertical displacement at the receiver wing and tailplane. The mean downwash gradients, in turn, depend mainly on the vertical separation between the tanker and receiver aircraft and the ratio of the tanker-to-receiver aircraft wing spans. Solutions of the linearised equations of motion were obtained for a range of values of the downwash gradients. The large receiver aircraft, considered in the paper, typically exhibits two divergent modes which appear to be controlled in flight by frequent alternate movement of the elevators and engine throttle. more...
- Published
- 1987
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119. Measurements and calculations of steady and oscillatory pressures on a low aspect ratio model at subsonic and transonic speeds
- Author
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D.G. Mabey and B.L. Welsh
- Subjects
Tailplane ,Shock (fluid dynamics) ,Oscillation ,Mechanical Engineering ,Thermodynamics ,Aerodynamics ,Mechanics ,Physics::Fluid Dynamics ,symbols.namesake ,Flow separation ,Mach number ,symbols ,Subsonic and transonic wind tunnel ,Transonic ,Mathematics - Abstract
Steady and time-dependent pressures have been measured for oscillatory pitching motion at frequencies of 0, 12, 33 and 70 Hz on a model of the AGARD SMP tailplane at Mach numbers from 0·65 to 1·20. Some wall interference effects at transonic speeds were observed. For attached flows at transonic speeds the time-dependent pressures are in good agreement with predictions according to Garner's semi-empirical theory, as long as the local Mach number upstream of the shock is less than 1·1. For separated flows the semi-empirical theory gives poor predictions, particularly for the imaginary component of the pressure. Flow separation causes large low frequency effects beyond the scope of the predictions. more...
- Published
- 1987
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120. The Design of Compression Structures for Minimum Weight
- Author
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D. J. Farrar
- Subjects
Stress (mechanics) ,Shear (sheet metal) ,Cross section (physics) ,Tailplane ,Materials science ,Fuselage ,business.industry ,Tension (physics) ,Structural engineering ,Tube (container) ,business ,Compression (physics) - Abstract
The primary structure of an aeroplane usually consists basically of a set of tubular beams. The main structural box of the wing or tailplane is a well-known example: a semi-monocoque fuselage is another. For any given loading condition of the aircraft the material in the tube is stressed mainly in tension, in shear, or in compression, depending on its location in the tube cross section.The aim of the designer is to make the material fulfil these three functions in the most economical manner. In tension, he is limited only by the quality of material available. In shear, this is again substantially the case, although it is well known that very light shear webs over great depths do not develop as high an effective failing stress as do more sturdy webs. This property of dependence on theintensity of loadingis much more marked in the case of the compression structure, which is liable to instability in various ways. more...
- Published
- 1949
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121. The Use of Carbon Fibre Composites in Helicopters
- Author
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H. F. Winny
- Subjects
Materials science ,Tailplane ,Glass fiber ,Composite number ,medicine ,Aerospace Engineering ,Strength testing ,Stiffness ,Fatigue testing ,Composite material ,medicine.symptom ,Boom - Abstract
The structural use of fibre composites in helicopters, both for primary and secondary structures, has been recognised for some time. In 1964, Westlands developed a glass fibre composite tail boom and tailplane for the Wasp helicopter (Fig. 1) and the results were encouraging. The non-corrodable structure of the glass composite is considered a great advantage, especially for Naval helicopters. Strength testing of the tail boom was successfully completed with a weight of the component close to the existing metal tail boom, but resonance testing showed that a small additional weight was necessary to meet the stiffness requirements. The tailplane in glass fibre composite showed an appreciable saving in weight and after satisfactorily completing static and fatigue testing, one is now flying on a Service aircraft. more...
- Published
- 1971
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122. Longitudinal Stability in Aeroplanes
- Author
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L.W. Bryant
- Subjects
Mathematical theory ,Downwash ,Engineering ,Tailplane ,Control theory ,business.industry ,Salient ,Longitudinal static stability ,Slipstream ,General Medicine ,Pitching moment ,business ,Motion (physics) - Abstract
THE mathematical theory of longitudinal stability appears to have been adequate to explain the salient features of the behaviour of aeroplanes in longitudinal motion. In general the provision of a stable slope to the static pitching moment curve has been found in practice to fulfil all requirements, and although increasing oscillations do on occasion occur, they are on the whole surprisingly rare. The reasons for this are fairly well recognised and are briefly indicated in what follows. There is little doubt, however, that the designers' principal difficulties centre round the complex interferences between the wings and the tailplane, particularly with the air‐screw running. The downwash from the centre section in many machines, even with no engine on, is quite unpredictable in the present state of knowledge, and the calculation of the downwash due to the slipstream has not yet been successfully made even in the simplest cases. Some attempt is here made to summarise the present position. more...
- Published
- 1933
- Full Text
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123. The Downwash of Swept-back Wings having the Leading Edge Separation
- Author
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Akira Mitsuyasu
- Subjects
Downwash ,Physics ,Leading edge ,Tailplane ,Lift (soaring) ,Mechanics ,Astrophysics::Galaxy Astrophysics ,Vortex - Abstract
The effects of the leading edge separation on the downwash of swept-back wings is discussed by the theoretical and experimental considerations. It is concluded that the occurrence of the part-span vortices extremely increase the downwash at tailplane. The downwash of swept-back wings having the leading edge separation should not be calculated only from the lift distribution, but also from the consideration of the existence of the leading edge separation vortices. more...
- Published
- 1957
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124. A Note on the Evaluation of the Supersonic Downwash Integral
- Author
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B. A. Hunn
- Subjects
Downwash ,Physics ,symbols.namesake ,Tailplane ,Wing ,Delta wing ,Mach number ,Plane (geometry) ,Plane symmetry ,Mathematical analysis ,General Engineering ,symbols ,Supersonic speed - Abstract
SummaryTo calculate tail loads in flight it is necessary to know the angle of downwash at all points of the tailplane for any given value of wing incidence. Current trends in aircraft design place the tailplane off the plane of the wing. There exist solutions for the downwash in the z=0 plane for a delta wing with subsonic leading edges. This note gives a form of integral suitable for numerical evaluation which determines the downwash in the plane of symmetry (y=0) of a delta wing with subsonic leading edges. This note also points out an apparent error in Ref. 4 by G. N. Ward and gives a closed form for the downwash at a point whose forward Mach cone totally includes an arrowhead wing with supersonic trailing edges and whose centre line coincides with the axis of the cone. more...
- Published
- 1954
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125. Structural Design
- Author
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K. Bentley
- Subjects
Engineering ,Philosophy of design ,Tailplane ,Cabin pressurization ,business.industry ,Principal (computer security) ,Service life ,Differential (mechanical device) ,General Medicine ,Aerospace engineering ,business ,Load carrying ,Marine engineering - Abstract
THE structural design of the BAC One‐Eleven generally follows closely that of the Vickcrs Vanguard and the VC10†—involving the use of a considerable number of integrally‐machined components. As a short‐haul aircraft the average time per flight of the BAC One‐Eleven is expected to be of the order of 45 min. during which period full cabin pressure differential will be attained, speeds of the order of its design cruising speeds will be achieved and the undercarriage and flaps will be operated for take‐off and landing. Based on current estimations this involves a design aim of a minimum crack‐free life of 40,000 flights, landings and take‐offs —a much more severe requirement than that for the long‐range subsonic jets. Critical areas of the aircraft (undercarriage, flaps, tailplane and cabin pressure skins) are thus designed on fatigue considerations related principally to the number of flights made. The accent has therefore been placed on building a rugged structure which is easy to maintain and has a long service life. Small amounts of additional weight, properly disposed, can effect large improvements in the service life, particularly necessary on a short‐haul aircraft, and although weight saving is always of prime importance it must be balanced by other factors—especially in the primary structure. more...
- Published
- 1963
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126. A Simplified Analysis of Static Longitudinal Stability
- Author
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Elliott G. Reid
- Subjects
Lift coefficient ,Tailplane ,business.product_category ,Position (vector) ,Mathematical analysis ,Root (chord) ,Longitudinal static stability ,Pitching moment ,business ,Statics ,Airplane ,Mathematics - Abstract
The first section of this paper describes the development of a single family of curves which illustrates the variation of the pitching moment coefficient with the lift coefficient for all wings and for all e.g. locations. The second consists of an analysis of the characteristics of these curves and their derivatives in conjunction with the known properties of tailplanes; the elements of a simplified theory of static stability are stated in four general theorems. In the third section, a direct method for the determination of tailplane area is given. An example of the use of the simplified analysis is appended. O ALL the problems which confront the airplane designer, that of providing an airplane with specified characteristics of static longitudinal stability is one of those least amenable to direct solution. This situation has its root in the difficulty of clearly describing the apparently complex relation between the wing pitching moment coefficient and the several variables which control its value. To be sure, there are analytical and nomographic methods, notably those developed by Stalker and Higgins, which enable fairly accurate calculation of the slope of the wing moment curve when the location of the center of gravity is known. However, visualization of more than the outstanding qualitative characteristics of the underlying relationship is precluded by the fact that for each e.g. position there is an unique relation between the slope of the wing moment curve and the lift coefficient. Such complexity precludes an entirely clear conception of the specific problems of design and makes the use of "cut and try" methods almost universal. The present paper describes a method of correlating the pitching moment characteristics of all practically useful wings, outlines the elements of the simplified theory of static longitudinal stability which naturally follows and illustrates the applicability of these principles to practical design problems. WING PITCHING MOMENTS The theorem of statics which states that any force may be replaced by a force and a couple justifies the replacement of the conventional wing vector sheaf, Fig. la, by its equivalent, Fig. lb, in which each force vector is accompanied by the couple Cm QmCm (Diagrams c 6 1 Edward A. Stalker, Principles of Flight, Chapter 14, The Ronald Press Company, New York, 1931. 2 George J. Higgins, A Study of the Pitching Moments and the Stability Characteristics of Monoplanes, N.A.C.A. Technical Note No. 511,1934. c 6 a more...
- Published
- 1937
- Full Text
- View/download PDF
127. Body and Tail Moments in Spin
- Author
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B.Sc and H.B. Irving
- Subjects
Engineering ,Fin ,Tailplane ,business.industry ,Blanketing ,General Medicine ,Rudder ,Monoplane ,Biplane ,Classical mechanics ,Nuclear magnetic resonance ,Tail moment ,business ,Spin (aerodynamics) - Abstract
IN the May, 1933, number of AIRCRAFT ENGINEERING there was published an article by Korvin‐Kroukovsky on the uncontrolled tail spin, in which one of the main points put forward was that during a spin both the body and the tail were very largely shielded by the wings. It was then argued from this that danger might be expected more especially in the low‐wing monoplane type and also the biplane with big forward stagger of wings. At the time there was very little direct evidence on the effect of wings on body and tail moment although an early report on the “ Bantam,” an unstaggered biplane which had spun into the ground, had shown pretty clearly that it was the tailplane which was responsible for the complete blanketing or even reversal of the fin and rudder in a flat spin, and that this could be remedied by raising the tailplanc. more...
- Published
- 1936
- Full Text
- View/download PDF
128. A Method of Calculating Space Free Resonance Modes of an Aircraft
- Author
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B. A. Hunn
- Subjects
Physics ,Matrix (mathematics) ,Tailplane ,Fuselage ,business.industry ,Normal mode ,Degrees of freedom ,Mathematical analysis ,Resonance ,Flutter ,Point (geometry) ,Aerospace engineering ,business - Abstract
The problem of deducing resonance modes of vibration of an aircraft in free space is a concomitant of flutter calculations if the number of degrees of freedom used is to be small. When the structure is complex in that it involves wings, fuselage and tailplane, each of which possesses infinitely many normal modes, it becomes apparent that the number of point masses which must be considered, in constructing a dynamical equivalent to give a sufficient coverage of the frequency range in which flutter is likely, is very large. For example, it may be necessary to use four rods per wing and per tailplane and four point masses on the fuselage. This would involve 8 + 8 + 4 degrees of freedom, and if the usual technique of characteristic roots is used it would be necessary to consider a characteristic root matrix of order 20 × 20. more...
- Published
- 1953
- Full Text
- View/download PDF
129. Koncepce jednotlivých kategorií letounů
- Author
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Zablatzký, Jiří, Jebáček, Ivo, Havránek, Jan, Zablatzký, Jiří, Jebáček, Ivo, and Havránek, Jan
- Abstract
Tato bakalářská práce se zabývá kategoriemi letounů a jejich koncepcemi. Hledá typické koncepce v jednotlivých kategoriích a vysvětluje důvody použití těchto koncepcí. Uvádí výhody a nevýhody jednotlivých koncepčních řešení z hlediska aerodynamického, konstrukčního, technologického a provozního., This bachelor’s thesis deals with categories of fixed-wing aircraft and their concepts. It searches for the typical concepts in each category and explains the reasons for using them. It brings out the advantages and disadvantages of the individual designs in terms of aerodynamics, structure, technology and operation. more...
130. Koncepce jednotlivých kategorií letounů
- Author
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Zablatzký, Jiří, Jebáček, Ivo, Havránek, Jan, Zablatzký, Jiří, Jebáček, Ivo, and Havránek, Jan
- Abstract
Tato bakalářská práce se zabývá kategoriemi letounů a jejich koncepcemi. Hledá typické koncepce v jednotlivých kategoriích a vysvětluje důvody použití těchto koncepcí. Uvádí výhody a nevýhody jednotlivých koncepčních řešení z hlediska aerodynamického, konstrukčního, technologického a provozního., This bachelor’s thesis deals with categories of fixed-wing aircraft and their concepts. It searches for the typical concepts in each category and explains the reasons for using them. It brings out the advantages and disadvantages of the individual designs in terms of aerodynamics, structure, technology and operation. more...
131. Koncepce jednotlivých kategorií letounů
- Author
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Zablatzký, Jiří, Jebáček, Ivo, Zablatzký, Jiří, and Jebáček, Ivo
- Abstract
Tato bakalářská práce se zabývá kategoriemi letounů a jejich koncepcemi. Hledá typické koncepce v jednotlivých kategoriích a vysvětluje důvody použití těchto koncepcí. Uvádí výhody a nevýhody jednotlivých koncepčních řešení z hlediska aerodynamického, konstrukčního, technologického a provozního., This bachelor’s thesis deals with categories of fixed-wing aircraft and their concepts. It searches for the typical concepts in each category and explains the reasons for using them. It brings out the advantages and disadvantages of the individual designs in terms of aerodynamics, structure, technology and operation. more...
132. Koncepce jednotlivých kategorií letounů
- Author
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Zablatzký, Jiří, Jebáček, Ivo, Zablatzký, Jiří, and Jebáček, Ivo
- Abstract
Tato bakalářská práce se zabývá kategoriemi letounů a jejich koncepcemi. Hledá typické koncepce v jednotlivých kategoriích a vysvětluje důvody použití těchto koncepcí. Uvádí výhody a nevýhody jednotlivých koncepčních řešení z hlediska aerodynamického, konstrukčního, technologického a provozního., This bachelor’s thesis deals with categories of fixed-wing aircraft and their concepts. It searches for the typical concepts in each category and explains the reasons for using them. It brings out the advantages and disadvantages of the individual designs in terms of aerodynamics, structure, technology and operation. more...
133. Koncepce jednotlivých kategorií letounů
- Author
-
Zablatzký, Jiří, Jebáček, Ivo, Havránek, Jan, Zablatzký, Jiří, Jebáček, Ivo, and Havránek, Jan
- Abstract
Tato bakalářská práce se zabývá kategoriemi letounů a jejich koncepcemi. Hledá typické koncepce v jednotlivých kategoriích a vysvětluje důvody použití těchto koncepcí. Uvádí výhody a nevýhody jednotlivých koncepčních řešení z hlediska aerodynamického, konstrukčního, technologického a provozního., This bachelor’s thesis deals with categories of fixed-wing aircraft and their concepts. It searches for the typical concepts in each category and explains the reasons for using them. It brings out the advantages and disadvantages of the individual designs in terms of aerodynamics, structure, technology and operation. more...
134. Preliminary tailplane design
- Author
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Egbert Torenbeek
- Subjects
Aerodynamic force ,business.product_category ,Tailplane ,Control theory ,Computer science ,Steady flight ,Control force ,Aerodynamics ,business ,Trim ,Airplane - Abstract
The aerodynamic design of the tailplane is based on many specific requirements regarding its functions, which are to provide equilibrium in steady flight (trim), to ensure that this condition is stable and that disturbances are well damped, and to generate aerodynamic forces for maneuvering the aircraft. The control forces involved must be acceptable to pilots, with the airplane both in trimmed and out-of-trim conditions. more...
- Published
- 1976
- Full Text
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135. Calculation of steady and unsteady pressures on wings at supersonic speeds with a transonic small disturbance code
- Author
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John T. Batina, Michael D. Gibbons, Dennis G. Mabey, Robert M. Bennett, and Samuel R. Bland
- Subjects
Physics ,Tailplane ,business.industry ,Aerodynamics ,Mechanics ,Aeroelasticity ,Physics::Fluid Dynamics ,symbols.namesake ,Flow (mathematics) ,Euler's formula ,symbols ,Supersonic speed ,Aerospace engineering ,business ,Transonic ,Freestream - Abstract
A transonic unsteady aerodynamic and aeroelasticity code has been developed for application to realistic aircraft configurations. The new code is called CAP-TSD which is an acronym for Computational Aeroelasticity Program - Transonic Small Disturbance. The CAP-TSD code uses a time-accurate approximate factorization algorithm for solution of the unsteady transonic small-disturbance equation that is efficient for solution of steady and unsteady transonic flow problems including supersonic freestream flows. The new code can treat complete aircraft geometries with multiple lifting surfaces and bodies. Applications to wings in supersonic freestream flow are presented. Comparisons with selected exact solutions from linear theory are presented showing generally favorable results. Calculations for both steady and oscillatory cases for the F-5 and RAE tailplane models are compared with experimental data and also show good overall agreement. Selected steady calculations are further compared with a steady flow Euler code. more...
- Published
- 1987
- Full Text
- View/download PDF
136. Large scale model tests of a new technology V/STOL concept
- Author
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D. G. Koenig and D. C. Whittley
- Subjects
Engineering ,Tailplane ,business.industry ,Nozzle ,Thrust ,Injector ,Mechanics ,Structural engineering ,Aerodynamics ,law.invention ,Fuselage ,law ,Duct (flow) ,business ,Scale model - Abstract
An ejector design concept for V/STOL aircraft, featuring a double-delta configuration with two large chordwise ejector slots adjacent to the fuselage side and a tailplane or canard for longitudinal control is examined. Large scale model tests of the concept have shown that ejector systems are capable of significant thrust augmentation at realistic supply pressures and temperatures, so that power plant size and weight can be reduced accordingly. A thrust augmentation of at least 1.75 can be achieved for the isolated ejector, not making allowance for duct and nozzle losses. Substantial reductions in velocity, temperature and noise of the lifting jet are assured due to mixing within the ejector - this lessens the severity of ground erosion and the thrust loss associated with reingestion. Consideration is also given to the effect of ground proximity, longitudinal aerodynamic characteristics, transition performance, and lateral stability. more...
- Published
- 1980
- Full Text
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137. Moving Tailplanes
- Author
-
F.G. Irving
- Subjects
Engineering ,Tailplane ,Elevator ,business.industry ,Aerodynamics ,symbols.namesake ,Mach number ,Control theory ,Parasitic drag ,symbols ,Trimming ,Supersonic speed ,business ,Transonic ,Simulation - Abstract
Publisher Summary This chapter describes the concept of moving tailplanes. Tailplanes that are adjustable for trimming purposes are much in favor for transonic and supersonic airplanes, since they obviate the difficulties associated with large changes of tab effectiveness at high Mach numbers. On low-speed airplanes, the only aerodynamic advantage is that the adjustable tail plus elevator may have slightly less profile drag under certain conditions of flight than the fixed tail/elevator/adjustable tab arrangement. On the other hand, the mechanism required to provide adjustment of the tail setting will tend to be heavier than that associated with a tab. High-speed airplanes frequently use all-moving tails, where the angle ηT is directly controlled by the movements of the pilot's control column. If the tailplane is moved via an irreversible power-control system, stick-free stability is no longer of significance, and suitable stick-forces can be arranged by artificial means. The object of such an arrangement is to avoid the difficulties associated with large changes of elevator effectiveness at high Mach numbers. more...
- Published
- 1966
- Full Text
- View/download PDF
138. Dynamic gain scheduled control of a Hawk scale model
- Author
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Mark H Lowenberg, A Dubs, Cdc Jones, and Thomas Richardson
- Subjects
020301 aerospace & aeronautics ,Engineering ,Tailplane ,business.industry ,Aerospace Engineering ,Control engineering ,02 engineering and technology ,Aerodynamics ,01 natural sciences ,010305 fluids & plasmas ,Scheduling (computing) ,Nonlinear system ,Gain scheduling ,0203 mechanical engineering ,Control theory ,0103 physical sciences ,Design process ,Transient response ,Actuator ,business - Abstract
When designing flight control laws using linearisations of an aircraft model about different flight conditions, some form of scheduling of the resultant gains will often be required to implement the controller over wide operating regions. In practice, the controller gains are often scheduled against relatively slowly-varying system states such as altitude or velocity. However, it may also be desirable to schedule gains against rapidly-varying states such as angle-of-attack, thereby generating a cyclic dependence through hidden coupling terms. Previous published work at Bristol has developed a numerical method of accounting for this dependence when scheduling state feedback gains against coupled states. The resulting ‘dynamic gain schedule’ is shown to significantly improve the transient response of the aircraft model during rapid manoeuvring and to reduce the chances of control surface actuator position limit saturation. In this paper, the novel design process, using eigenstructure assignment, is applied to a mathematical second-order longitudinal aircraft model which represents an approximate BAe Hawk wind-tunnel model. The dynamic gain scheduled controller is shown to work extremely well in practice when applied to the closed-loop experimental rig. Despite the highly nonlinear characteristics of the model aerodynamics and tailplane actuation system, as well as unmodelled high turbulence levels, dynamic gain scheduling demonstrates stable closed loop control even in regions where the nonlinearities are such that conventional gain scheduling fails to produce a stable response. more...
139. RANS Simulation and Experiments on the Stall Behaviour of an Airfoil with Laminar Separation Bubbles
- Author
-
Ralf Wokoeck, Vlad Ciobaca, Rolf Radespiel, Jens Ortmanns, Normann Krimmelbein, and Andreas Krumbein
- Subjects
Airfoil ,Physics ,Transition Prediction ,Tailplane ,Stall ,Turbulence ,Bubble ,RANS ,Laminar flow ,Stall (fluid mechanics) ,Mechanics ,Physics::Fluid Dynamics ,Trailing edge ,Laminar Separation Bubbles Transition ,Reynolds-averaged Navier–Stokes equations ,Simulation - Abstract
Measurements and simulations are presented of the flow past a tailplane research airfoil which is designed to show a mixed leading-edge trailing-edge stall behaviour. The numerical simulations were carried out with two flow solvers that introduce transition prediction based on linear stability theory to RANS simulations for cases involving laminar separation bubbles. One of the methods computes transition locations across laminar separation bubbles whereas the other assumes transition onset where laminar separations occur. For validation of the numerical methods an extensive measurement campaign has been carried out. It is shown, that the methodology mentioned first can simulate the size of laminar separation bubbles for angles of attack up to where the separation bubble and the turbulent separation at the trailing edge are well behaved and steady in the mean. With trailing edge separation involved, the success of the new numerical procedure relies on the diligent choice of a turbulence model. Cases with large 3D flow structures inside the turbulent trailing edge separations in windtunnel experiments for high angles of attack are compared and analysed along with 2D and 3D steady RANS calculations that model the measurement section of the windtunnel. more...
140. Experiments and analyses on post-buckling behavior of stringer-stiffened laminated composite helicopter tailplane
- Author
-
Vittorio Giavotto and Chiara Bisagni
- Subjects
Materials science ,Tailplane ,Deformation (mechanics) ,business.industry ,Composite number ,Structural engineering ,Load cell ,Finite element method ,Stringer ,Buckling ,Composite material ,business ,Envelope (mathematics) ,Strain gauge - Abstract
The present paper describes the results of an experimental and numerical investigation on a composite laminated helicopter tailplane, whose lower panels are subjected to buckling phenomena during the life envelope. The structure is made of carbon fabric, carbon unidirectional and honeycomb. Two different types of lower laminate composite panels are investigated: Z stringer-stiffened panels and L stringer-stiffened panels. During the tests, the applied load is measured using a load cell, the displacement of the tailplane ends using potentiometers and the panels strains using strain gauges. Moire’ fringes are installed to highlight the panels deformation in the lower part of the structure. At the beginning three Z stringer-stiffened and three L stringer-stiffened laminate composite lower panels are tested until 85% of the target load. Then the last L stringer-stiffened panel is tested until collapse. The buckling load happens at 63% of the target load, while the collapse happens at 90%. At the same time, the finite element analyses of the tailplane structures with both Z stringerstiffened and L stringer-stiffened panels are performed, simulating the dynamic of a slow compression test, using LS-DYNA. The finite element results are compared with the experimental data, obtaining an excellent numerical-experimental correlation. Indeed the collapse of the structure is predicted at 93% of the target load and experimentally happened at 90%. more...
141. Rear-Engined Air Liners
- Author
-
A. W. J. Smith
- Subjects
Jet (fluid) ,Tailplane ,Computer science ,Mechanical engineering ,Point (geometry) ,Preference - Abstract
I Should like to raise a point on the projected rear-engined jet air liners now under active consideration by several major British firms and of which “artists’ impressions” have recently been published, the latest being the V.C.10.The rear-engine layout has so many advantages that its use seems entirely logical, but I am curious to know whether or not such a design has been investigated with a noseplane layout in preference to the conventional tailplane. I have been interested in this possible configuration for some years and put the idea forward in a short Branch lecture at Derby when it appeared that quite a few of those then present agreed in broad principle. more...
- Published
- 1958
- Full Text
- View/download PDF
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