Helicopter flight simulation after rotor blade failure for accident investigation

1998 ◽  
Author(s):  
Olympio Mello
Keyword(s):  
Rotor Blade ◽  
Flight Simulation ◽  
Accident Investigation ◽  
Helicopter Flight ◽  
Blade Failure

Helicopter Rotor Blade Flexibility Simulation for Aeroelasticity and Flight Dynamics Applications

2014 ◽  
Vol 59 (4) ◽  
pp. 1-18 ◽  
Author(s):  
Ioannis Goulos ◽  
Vassilios Pachidis ◽  
Pericles Pilidis
Keyword(s):  
Real Time ◽  
Rotor Blade ◽  
Flight Dynamics ◽  
Integrated Approach ◽  
Flight Simulation ◽  
Response Characteristics ◽  
Helicopter Flight ◽  
Finite State ◽  
The Time Domain ◽  
Blade Loads

This paper presents a mathematical model for the simulation of rotor blade flexibility in real-time helicopter flight dynamics applications that also employs sufficient modeling fidelity for prediction of structural blade loads. A matrix/vector-based formulation is developed for the treatment of elastic blade kinematics in the time domain. A novel, second-order-accurate, finite-difference scheme is employed for the approximation of the blade motion derivatives. The proposed method is coupled with a finite-state induced-flow model, a dynamic wake distortion model, and an unsteady blade element aerodynamics model. The integrated approach is deployed to investigate trim controls, stability and control derivatives, nonlinear control response characteristics, and structural blade loads for a hingeless rotor helicopter. It is shown that the developed methodology exhibits modeling accuracy comparable to that of non-real-time comprehensive rotorcraft codes. The proposed method is suitable for real-time flight simulation, with sufficient fidelity for simultaneous prediction of oscillatory blade loads.

Design of a Transonic High-Pressure Turbine Stage 2D Section With Reduced Rotor/Stator Interaction

2004 ◽  
Author(s):  
Michele Vascellari ◽  
Re´my De´nos ◽  
Rene´ Van den Braembussche
Keyword(s):  
Rotor Blade ◽  
Static Pressure ◽  
Aerodynamic Force ◽  
Pressure Fluctuations ◽  
Uniform Field ◽  
Turbine Stage ◽  
Rotor Stator Interaction ◽  
Transonic Turbine ◽  
Blade Failure ◽  
Rotor Profiles

In transonic turbine stages, the exit static pressure field of the vane is highly non-uniform in the pitchwise direction. The rotor traverses periodically this non-uniform field and large static pressure fluctuations are observed around the rotor section. As a consequence the rotor blade is submitted to significant variations of its aerodynamic force. This contributes to the high cycle fatigue and may result in unexpected blade failure. In this paper an existing transonic turbine stage section is redesigned in the view of reducing the rotor stator interaction, and in particular the unsteady rotor blade forcing. The first step is the redesign of the stator blade profile to reduce the stator exit pitchwise static pressure gradient. For this purpose, a procedure using a genetic algorithm and an artificial neural network is used. Next, two new rotor profiles are designed and analysed with a quasi 3D Euler unsteady solver in order to investigate their receptivity to the shock interaction. One of the new profiles allows reducing the blade force variation by 50%.

Distributed Turbulence Model with Rigorous Spatial Cross-Correlation for Simulation of Helicopter Flight in Atmospheric Turbulence

2019 ◽  
Vol 64 (4) ◽  
pp. 1-13
Author(s):  
Honglei Ji ◽  
Renliang Chen ◽  
Pan Li
Keyword(s):  
Atmospheric Turbulence ◽  
Turbulence Model ◽  
Cross Correlation ◽  
Turbulence Models ◽  
Flight Test ◽  
Longitudinal Direction ◽  
Flight Simulation ◽  
Quality Analysis ◽  
Frequency Range ◽  
Helicopter Flight

This paper presents a distributed turbulence model with rigorous spatial cross-correlation for helicopter flight simulation in atmospheric turbulence and for future handling-quality analysis. First, digital filters with longitudinal correlations of the von Kármán turbulence are developed to generate discrete turbulence velocity components. Meanwhile, transverse turbulence correlations are considered by relating the filters in different positions with mathematically rigorous spatial cross-correlation. Then, the distributions of the related filters on the transverse plane in front of helicopter and their velocity components in the longitudinal direction of airspeed, as well as turbulence models of helicopter aerodynamic surfaces, are established. Finally, a flight dynamics model coupled with the turbulence model is developed and validated against the flight-test data. The proposed model can achieve accurate real-time simulations of helicopter response to atmospheric turbulence in the frequency range of interest of handling qualities. The effect of transverse turbulence correlations on helicopter frequency response is also analyzed. The results show that the simulation model regardless of transverse turbulence correlations would aggravate the "rotor-to-body attenuation" effect of the main rotor and therefore underpredict the helicopter roll, pitch, and heave rate responses to atmospheric turbulence in the frequency range of interest.

Objective and subjective evaluations of flight simulator fidelity

2012 ◽  
Vol 25 (0) ◽  
pp. 91 ◽  
Author(s):  
Li Wong ◽  
Georg Meyer ◽  
Emma Timson ◽  
Philip Perfect ◽  
Mark White
Keyword(s):  
Tracking Error ◽  
Flight Simulation ◽  
Flight Training ◽  
Motion Platform ◽  
Subjective Data ◽  
Helicopter Flight ◽  
Objective Performance ◽  
Objective Performance Measures ◽  
Simulator Motion ◽  
Task Oriented

There is interest in how pilots perceive simulator fidelity and rate self-performance in virtual reality flight training. Ten participants were trained to perform a target tracking task in a helicopter flight simulation. After training objective performance, the median tracking error, was compared to subjective self-evaluations in a number of flying conditions where the cues available to our pilots were manipulated in a factorial design: the simulator motion platform could be active or static, audio cues signalling the state of the turbine could be those used during training, non-informative, or an obviously different but informative ‘novel’ sound. We tested participants under hard and easy flying conditions. Upon completion of each test condition, participants completed a 12-statement Likert-scale with items concerning their performance and helicopter simulator fidelity. Objective performance measures show that flight performance improved during training and was affected by audio and motion cues. The subjective data shows that participants reliably self-evaluated their own performance and simulator fidelity. However, there were instances where subjective and objective measures of performance or fidelity did not correlate. For example, although participants rated the ‘novel’ turbine sound as having low fidelity, it behaviourally caused no difference with respect to the turbine sound used in training. They were also unable to self-evaluate outcome of learning. We conclude that whilst subjective measures are a good indicator of self-performance, objective data offers a valuable task-oriented perspective on simulator fidelity.

Helmet Mounted Display Systems for Helicopter Simulation

1989 ◽  
Vol 33 (2) ◽  
pp. 86-90 ◽  
Author(s):  
Loran A. Haworth ◽  
Nancy Bucher ◽  
David Runnings
Keyword(s):  
Visual Information ◽  
Vertical Motion ◽  
Visual Display ◽  
Flight Simulation ◽  
Wide Field ◽  
Critical Research ◽  
Helicopter Flight ◽  
Motion Simulator ◽  
Wide Field Of View ◽  
Display Systems

Simulation scientists continually pursue improved flight simulation technology with the goal of closely replicating the “real world” physical environment. The presentation/display of visual information for flight simulation is one such area enjoying recent technical improvements that are fundamental for conducting simulated operations close to the terrain. Detailed and appropriate visual information is especially critical for Nap-Of-the-Earth (NOE) helicopter flight simulation where the pilot maintains an “eyes-out” orientation to avoid obstructions and terrain. This paper elaborates on the visually-coupled Wide Field Of View Helmet Mounted Display (WFOVHMD) system technology as a viable visual display system for helicopter simulation. In addition the paper discusses research conducted on the NASA-Ames Vertical Motion Simulator that examined one critical research issue for helmet mounted displays.

Helicopter flight simulation trim in the coordinated turn with the hybrid genetic algorithm

2017 ◽  
Vol 233 (3) ◽  
pp. 1159-1168 ◽  
Author(s):  
Wei Wang ◽  
Dongsheng Li ◽  
Chun Liu
Keyword(s):  
Genetic Algorithm ◽  
Hybrid Genetic Algorithm ◽  
Flight Test ◽  
Flight Simulation ◽  
Control Vector ◽  
Experimental Platform ◽  
Helicopter Flight ◽  
Quasi Newton ◽  
General Method ◽  
Good Agreement

Helicopter trim models are multivariate nonlinear equations and it is difficult to determine these initial trim points comparable to flight conditions. To solve this question, a hybrid genetic algorithm is presented in this paper, that combines the quick convergence ability of the quasi-Newton method and the advantages of genetic algorithm, such as global convergence. The trim control vector and the constraint conditions were established in the coordinated-turn based on the helicopter flight dynamic model. The coordinated turn flight of a UH-60 A helicopter was taken as an example to simulate on the experimental platform. Comparisons were made between the trim results and flight test data and there is a good agreement among them, and the efficiency of the algorithm presented is verified. It is a general method that can be applied to trim the helicopter of different flight conditions.

Simulation-Based Helicopter Mission Effectiveness Evaluation Method

2014 ◽  
Vol 651-653 ◽  
pp. 962-965
Author(s):  
Ji Cai ◽  
Hu Liu ◽  
Hong Tang
Keyword(s):  
Evaluation Method ◽  
Weight Coefficient ◽  
Flight Simulation ◽  
Effectiveness Evaluation ◽  
Simulation Data ◽  
Advantages And Disadvantages ◽  
Helicopter Flight ◽  
Parameter Evaluation ◽  
Simulation Based ◽  
Mission Effectiveness

It is always difficult to obtain a reliable result of helicopter mission effectiveness evaluation (HMEE) by traditional methods. In order to solve the problem, this paper compared and analysed advantages and disadvantages of traditional effectiveness evaluation methods, and presented a simulation-based helicopter mission effectiveness evaluation method. The method is based on the simulation data. The method combines with advantages of multi parameter evaluation method, computer simulation evaluation method and logarithmic evaluation method. By using the reliable helicopter flight simulation data and an objective weight coefficient calculation methods, we can get accurate and reliable helicopter mission effectiveness value. Research proves that this method can be applied in the field of effectiveness evaluation.

Design, Flight Simulation, and Handling Qualities Evaluation of an LPV Gain-Scheduled Helicopter Flight Control System

2000 ◽  
Vol 6 (6) ◽  
pp. 553-566 ◽  
Author(s):  
Ian Postlethwaite ◽  
Ioannis K. Konstantopoulos ◽  
Xiao-Dong Sun ◽  
Daniel J. Walker ◽  
Adrian G. Alford
Keyword(s):  
Control System ◽  
Flight Control ◽  
Flight Simulation ◽  
Flight Control System ◽  
Handling Qualities ◽  
Helicopter Flight ◽  
Gain Scheduled
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