scholarly journals Wind Tunnel Flutter Testing of Composite T-Tail Model of a Transport Aircraft with Fuselage Flexibility

10.5772/21628 ◽  
2011 ◽  
Author(s):  
Raja Samikkannu
Keyword(s):  
Wind Tunnel ◽  
Transport Aircraft ◽  
Flutter Testing

scholarly journals Features of flow around transport aircraft model with running propellers by modelled engine failure in wind tunnel

2021 ◽  
Vol 2103 (1) ◽  
pp. 012206
Author(s):  
V I Chernousov ◽  
A A Krutov ◽  
E A Pigusov
Keyword(s):  
Wind Tunnel ◽  
Lift Coefficient ◽  
Aerodynamic Characteristics ◽  
Light Transport ◽  
Transport Aircraft ◽  
Engine Failure ◽  
The One ◽  
Low Speed Wind Tunnel ◽  
Control Surfaces ◽  
Landing Mode

Abstract This paper presents the experiment results of modelling the one engine failure at the landing mode on a model of a light transport airplane in the T-102 TsAGI low speed wind tunnel. The effect of starboard and port engines failure on the aerodynamic characteristics and stability of the model is researched. The model maximum lift coefficient is reduced about ≈8% and there are the same moments in roll and yaw for starboard and port engines failure case. It was found that the failure of any engine has little impact on the efficiency of control surfaces. Approaches of compensation of forces and moments arising in the engine failure case were investigated.

Post-stall flight dynamics of commercial transport aircraft configuration: A nonlinear bifurcation analysis and validation

2020 ◽  
pp. 095441002094408
Author(s):  
Fei Cen ◽  
Qing Li ◽  
Zhitao Liu ◽  
Lei Zhang ◽  
Yong Jiang
Keyword(s):  
Wind Tunnel ◽  
Bifurcation Analysis ◽  
Large Angle ◽  
Unsteady Aerodynamics ◽  
Time History ◽  
Periodic Oscillation ◽  
Flight Dynamics ◽  
Flight Test ◽  
Loss Of Control ◽  
Transport Aircraft

Loss-of-control has become the largest fatal accident category for worldwide commercial jet accidents, and any initiative aimed at preventing such events requires an understanding of the fundamental aircraft behavior, especially the flight dynamics at post-stall region at which loss-of-control usually occurred. A series of low-speed static and dynamic wind tunnel tests of the Common Research Model over a large angle of attack/sideslip envelope was conducted and a non-linear aerodynamic model was developed. The bifurcation analysis, complemented by time-history simulation was used to understand the post-stall flight dynamics and the numerical analysis results were preliminary validated by wind tunnel virtual flight test. Several representative post-stall behaviors for the transport aircraft have been identified, including departure, periodic oscillation, post-stall gyration and steep spiral, etc. Furthermore, the predicted periodic oscillation in pitch motion has been perfectly duplicated in wind tunnel virtual flight test. The approach used in this work shows a promising way to uncover the flight dynamics of transport aircraft at extreme and loss-of-control flight conditions, as well as to apply to nonlinear unsteady aerodynamics modeling and validation, flight accident investigation, advanced flight control law design or studying initiative for loss-of-control prevention or mitigation.

Supersonic Unstalled Flutter In Fan Rotors; Analytical and Experimental Results

1974 ◽  
Vol 96 (4) ◽  
pp. 379-386 ◽  
Author(s):  
L. E. Snyder ◽  
G. L. Commerford
Keyword(s):  
Wind Tunnel ◽  
High Speed ◽  
Reduced Frequency ◽  
Cascade Analysis ◽  
Blade Shape ◽  
Supersonic Flutter ◽  
Transonic Fan ◽  
Flutter Testing ◽  
Stagger Angle ◽  
Interblade Phase Angle

Supersonic unstalled flutter is predicted using an unsteady supersonic cascade analysis, a cascade wind tunnel and a high speed fan rotor. Since the unsteady analysis assumes thin flat plate airfoils, the effect of thickness and blade shape was examined experimentally by flutter testing two sets of supersonic blading in a cascade wind tunnel. The effects of changes in Mach number, reduced frequency, stagger angle and interblade phase angle were examined from the analysis and tests. Results show that the trends are in agreement, but that blade shape has an effect on the level of reduced velocity at the incipient flutter point. The unsteady aerodynamic analysis is applied to two transonic fan stages. The first rotor was designed as a supersonic flutter test vehicle while the second was designed to be flutter free. Results of the fan tests show that the analysis correctly predicts the susceptibility to flutter of each rotor.

Advanced data processing to control wind tunnel experiments on DLR-F9 transport aircraft model

1997 ◽  
Author(s):  
Jens Trapp ◽  
Hans-Georg Pagendarm ◽  
Robert Zores ◽  
Jens Trapp ◽  
Hans-Georg Pagendarm ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Data Processing ◽  
Wind Tunnel Experiments ◽  
Transport Aircraft ◽  
Aircraft Model

Optimal Excitation for Aircraft Flutter Testing

1995 ◽  
Vol 209 (4) ◽  
pp. 313-325 ◽  
Author(s):  
A P Burrows ◽  
J R Wright ◽  
J A Coote
Keyword(s):  
Wind Tunnel ◽  
Signal Amplitude ◽  
Frequency Range ◽  
Wind Tunnel Model ◽  
Variable Amplitude ◽  
Excitation Signal ◽  
Tunnel Model ◽  
Optimal Excitation ◽  
Variable Power ◽  
Flutter Testing

The choice of excitation signal for flutter testing of a full-scale aircraft or wind tunnel model is crucial if the flutter test clearance is to be performed quickly and with confidence. The use of chirps (that is, sinusoidal signals with varying frequency) is commonplace but has limitations. In this paper the idea of a simple chirp is extended to the development of a multi-sectional variable amplitude/variable power chirp in which the relative signal amplitude and power between sections may be specified over the frequency range of interest. An optimal chirp for a particular application may thus be designed. Sample results from a wind tunnel model flutter test are presented. In addition, the practice of sweeping up and then down in frequency is shown to be inadvisable under certain circumstances.

Stalling transport aircraft

2013 ◽  
Vol 117 (1198) ◽  
pp. 1183-1206 ◽  
Author(s):  
P. J. Bolds-Moorehead ◽  
V. G. Chaney ◽  
T. Lutz ◽  
S. Vaux
Keyword(s):  
Wind Tunnel ◽  
Flight Control ◽  
Flight Test ◽  
High Angle ◽  
Flight Testing ◽  
Control Laws ◽  
Transport Aircraft ◽  
Wind Tunnel Data ◽  
Predictive Validation ◽  
Flight Deck

Abstract Airbus and Boeing are cooperatively presenting this topic dealing with transport aircraft stalls. The paper will begin by defining a stall, followed by a review of requirements, predictive validation and flight testing. There are various ways of designing modern jet transports for the stall regime such as aerodynamic approaches, flight deck indications, and augmentation control laws to deal with the high angle-of-attack (α) arena. The goal of augmented control laws for high α is common – no full aerodynamic stall or loss of climb performance should occur in the operational flight envelope, in Normal flight control modes. The validation techniques employed in preparation for a flight test campaign will follow. These include flight characteristic predictions based on wind-tunnel data as well as pilot-in-the-loop simulation rehearsals. The preparation for flight testing will be reviewed from both the engineer and pilot viewpoints. This will be followed by a review of various flight testing that has been conducted. The paper will close with a brief foray into what the future of transport stalls could be – perhaps protection features in degraded flight control modes? What are the benefits as well as drawbacks to increased augmentation for high α?

scholarly journals Analysis of the propellers-airframe interaction of the light transport aircraft

2021 ◽  
Vol 24 (5) ◽  
pp. 76-88
Author(s):  
Yu. S. Mikhailov
Keyword(s):  
Wind Tunnel ◽  
Experimental Studies ◽  
Aerodynamic Characteristics ◽  
High Energy ◽  
Light Transport ◽  
Transport Aircraft ◽  
High Energy Level ◽  
Combined Use ◽  
Wind Tunnel Balance ◽  
Propeller Blades

In the design of multi-engine aircraft, one of the important issues is the interaction between the propellers and airframe configuration components, especially in take-off and go-around procedure modes. Modern propeller-driven aircraft concepts in the pulling configuration are characterized by a high disk loading and an increased number of propeller blades used to increase cruising speed and reduce excessive noise. The first problem arising due to high disk loading is the direct impact of forces by operating propellers (thrust, normal force) on fixed-wing stability, especially at angles of attack different from a zero value. The second one involves a high-energy level of the propeller slipstream, having a significant indirect impact on the aircraft’s aerodynamics, stability and controllability. This impact is primarily associated with the interaction of propellers slipstream with other aircraft’s configuration elements. The complexity of taking into account the slipstream-wing interaction and other airframe components stipulated the application of experimental methods to study the problems of propellers – airframe interaction while designing propeller-driven aircraft configurations. This article presents an analysis of the experimental studies results of the operating propellers- airframe interaction for a light twin-engine transport aircraft. The aerodynamic aircraft’s configuration is executed using the conventional pattern of a high-wing and the carrier-on deck type empennage. The high-lift wing device is a fixed-vane doubleslotted flap. The wind-tunnel tests of the model in the cruising, takeoff and landing configurations were carried out in TsAGI lowspeed wind-tunnel T-102. Measurement of forces and moments, acting on the model, was performed by means of an external sixcomponent wind-tunnel balance. Measurement of forces and moments, acting on the propeller, was conducted using strain gauge weighers installed inside the engine nacelles of power plant simulators. The simultaneous combined use of external and internal balances allowed researchers to determine the direct and indirect contribution of operating propellers to the model longitudinal aerodynamic characteristics under variation of loading factor B ranging from 0 to 2.

Optimization of the three-segment aerofoil arrangement based on wind tunnel tests and numerical analysis

2020 ◽  
pp. 095441002092602
Author(s):  
Wojciech Grendysa ◽  
Bartosz Olszański
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Tunnel ◽  
Response Surface ◽  
Lift Coefficient ◽  
Light Transport ◽  
Optimization Approach ◽  
Wind Tunnel Tests ◽  
Transport Aircraft ◽  
Aerodynamic Configuration

This paper presents the optimization of multi-element aerofoil for the LAR-3 Puffin -- STOL light transport aircraft concept proposal. Based on the geometry and aerodynamic characteristics of the well-known and proven in flight three-segment NACA 63A416 aerofoil, the authors explore the possibility of enhancing its high-lift performance by the movement of slot and flap position in extended (deployed) aerodynamic configuration. In order to determine the optimum positions of aerofoil segments (elements), a multi-step optimization approach was developed. It combines computational fluid dynamics simulations that were used for design space screening and preliminary optimization together with low-turbulence wind tunnel tests which yielded certain results. To decrease the numerical cost of the computer simulation campaign, Design of experiment methods (optimal space-filling design among others) were employed instead of exhausting full factorial (parametric) design. Response surface models of major aerodynamic coefficients (lift, drag, pitching moment) at predicted maximum lift coefficient ( C L max) point allowed to narrow down search space and identify several candidates for optimal configuration to be checked experimentally. Wind tunnel tests campaign confirmed the major trends observed in computational fluid dynamics derived response surface contour plots. For the optimum aerodynamic configuration, chosen experimental C L max is over 3.9, which is a 10% increase over the baseline (initial slat and flap positions) case. In parallel, the maximum lift-to-drag ratio gain at that point was almost 19%. The research outlined in this paper was conducted on behalf of the aircraft production company and its results will be applied in a newly designed transport aircraft.

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