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 A Review of Wind Tunnel Based Virtual Flight Testing Techniques for Evaluation of Flight Control Systems

2015 ◽  
Vol 2015 ◽  
pp. 1-22 ◽  
Author(s):  
Min Huang ◽  
Zhong-wei Wang
Keyword(s):  
Wind Tunnel ◽  
Control Systems ◽  
Flight Control ◽  
Wind Tunnel Test ◽  
Flight Test ◽  
Evaluation Methods ◽  
Test System ◽  
Hardware In The Loop ◽  
Flight Testing ◽  
Testing Techniques

Wind tunnel based Virtual Flight Testing (VFT) is a dynamic wind tunnel test for evaluating flight control systems (FCS) proposed in recent decades. It integrates aerodynamics, flight dynamics, and FCS as a whole and is a more realistic and reliable method for FCS evaluation than traditional ground evaluation methods, such as Hardware-in-the-Loop Simulation (HILS). With FCS evaluated by VFT before flight test, the risk of flight test will be further reduced. In this paper, the background, progress, and prospects of VFT are systematically summarized. Specifically, the differences among VFT, traditional dynamic wind tunnel methods, and traditional FCS evaluation methods are introduced in order to address the advantages of evaluating FCS with VFT. Secondly, the progress of VFT is reviewed in detail. Then, the test system and key technologies of VFT for FCS evaluation are analyzed. Lastly, the prospects of VFT for evaluating FCS are described.

Divergence Speed Prediction for Practical Slung Load Shapes

2015 ◽  
Author(s):  
Brandon Liberi ◽  
Chau Ton ◽  
Narayanan Komerath
Keyword(s):  
Control System ◽  
Robust Control ◽  
Wind Tunnel ◽  
Flight Control ◽  
Flight Control System ◽  
Wind Tunnel Experiments ◽  
Flight Testing ◽  
Flight Vehicles ◽  
Analytical Functions ◽  
Speed Prediction

Given the innumerable combinations of flight vehicles, loads and flight conditions, alternatives are sought to flight testing, to certify the safe flight speed with slung loads. With well-resolved airload maps now feasible for arbitrary shapes as analytical functions, dynamic simulation predicts divergence speeds, regardless of the symmetry of the object. Likely modes of amplification are found using wind tunnel experiments with free-swinging objects. A robust control formulation enables safe flight close to divergence speed where the flight control system can prevent disturbance amplification.

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.

Design of the wind tunnel based virtual flight testing evaluation method for flight control systems

2016 ◽  
Vol 232 (1) ◽  
pp. 17-29
Author(s):  
Min Huang ◽  
Zhong-wei Wang ◽  
Zhen-yun Guo ◽  
Yao-bin Niu
Keyword(s):  
Control System ◽  
Wind Tunnel ◽  
Control Systems ◽  
Flight Control ◽  
Evaluation Method ◽  
Simulation Models ◽  
Hardware In The Loop ◽  
Flight Control System ◽  
Flight Testing ◽  
Simulation Evaluation

In order to provide a method for evaluating flight control systems with the wind tunnel based virtual flight testing and provide a guide for building virtual flight testing systems, the virtual flight testing evaluation method was researched. The virtual flight testing evaluation method consisted of three parts: virtual flight testing method, virtual flight testing data processing method, and flight control system performance determination method, which were respectively designed for a pitching control system. Then, the hardware-in-the-loop simulation evaluation method was presented, and comparisons between the virtual flight testing and hardware-in-the-loop simulation evaluation method were conducted to highlight the characteristics of virtual flight testing evaluation method. Finally, virtual flight testing simulation models of a sample air vehicle were built and virtual flight testing were simulated to demonstrate the virtual flight testing evaluation method, which is helpful for the understanding of the virtual flight testing evaluation method with more sensibility. The evaluation results show that the virtual flight testing evaluation method designed can be used for flight control system evaluation.

The Operator's View

1967 ◽  
Vol 71 (683) ◽  
pp. 758-761 ◽  
Author(s):  
D. F. Redrup
Keyword(s):  
Flight Test ◽  
Crew Member ◽  
Flight Testing ◽  
Long Period ◽  
Test Programme ◽  
Airline Pilot ◽  
Certification Programme ◽  
Design Defects ◽  
Cockpit Design ◽  
Flight Deck

The Airline Pilot has little to do with Flight Testing for Certification, in fact, apart from a few specialist pilots in the airlines the average airline pilot takes no part in the Flight Test Programme.Once an aircraft has been certificated, however, the airline pilot spends more time on the Flight Deck and has longer to experience the shortcomings of the Certification Programme than anyone else. He is then the Consumer, the man who spends hours with an expensive piece of machinery strapped to him and who suffers over a long period of time any cockpit design defects. For that reason a large part of this paper will be devoted to, I hope, useful criticism of Flight Deck Layouts as they affect the operating crew member.

Design of Dynamic Inversion and Explicit Model Following Flight Control Laws for Quadrotor UAS

2020 ◽  
Vol 65 (3) ◽  
pp. 1-16
Author(s):  
Umberto Saetti ◽  
Joseph F. Horn ◽  
Sagar Lakhmani ◽  
Constantino Lagoa ◽  
Tom F. Berger
Keyword(s):  
Flight Control ◽  
Flight Test ◽  
Parametric Model ◽  
Unmanned Aerial Systems ◽  
Model Parameters ◽  
Dynamic Inversion ◽  
Explicit Model ◽  
Control Laws ◽  
Model Following ◽  
Novel Approach

The objectives of this paper are to advance dynamic inversion (DI) and explicit model following (EMF) flight control laws for quadrotor unmanned aerial systems (UAS) and to develop an efficient strategy to compute the stability and performance robustness statistics of such control laws given parametric model uncertainty. For this purpose, a parametric model of a quadrotor is identified from flight-test data. The identified model is validated both in frequency and time domains. Next, DI and EMF flight control laws are designed for both inner attitude and outer velocity loops. Finally, a novel approach based on an unscented transform is used to evaluate the statistics of the controller's performance based on the statistics of the uncertain model parameters.

Flight Simulator as a Tool for Flight Control System Synthesis and Handling Qualities Research

2009 ◽  
Vol 147-149 ◽  
pp. 231-236 ◽  
Author(s):  
Tomasz Rogalski ◽  
Andrzej Tomczyk ◽  
Grzegorz Kopecki
Keyword(s):  
Control System ◽  
Control Systems ◽  
Flight Control ◽  
Flight Simulator ◽  
Flight Control System ◽  
Aircraft Control ◽  
Flight Testing ◽  
Flight Tests ◽  
Control Laws ◽  
Handling Qualities

At the Department of Avionics and Control Systems problems of aeronautical control systems have been dealt with for years. Several different kinds of aeronautical control systems have been designed, prototyped and tested. These control systems are intended for general aviation aircraft and unmanned aircraft. During all research projects computer simulations and laboratory tests were made. However, since in some cases such tests were insufficient, in-flight tests were conducted leading to a series of reliable results. The in-flight tests were made with the use of M-20 Mewa aircraft (autopilot for a GA aircraft) and PZL-110 Koliber aircraft (control system for UAV and indirect flight control system for a GA aircraft). Nevertheless, in-flight testing is very expensive and problematic. To avoid some problems appearing during in-flight tests and their preparation, a simulator – which is normally used for professional pilot training – can be used. The Aviation Training Center of the Rzeszów University of Technology possesses the ALSIM AL-200 MCC flight simulator. We have started preparing this simulator for the research. It is possible to control the simulated aircraft with the use of an external control system. The solution proposed enables testing the aircraft control algorithms, indirect control laws (e.g. control laws modifying handling qualities), as well as testing and assessment of the students’ pilotage skills. Moreover, the solution makes it possible to conduct tests connected with aircraft control, crew management, crew cooperation and flight safety. The simulator allows us to test dangerous situations, which – because of safety reasons – is impossible during in-flight testing. This paper presents modifications to the simulator’s hardware and additional software, which enable the described research.

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