A low-cost flight simulation for rapid handling qualities evaluations during design

During the development of the Boeing CH-47D helicopter flight simulation model, test pilots reported mismatch between the flight simulator results and flight test data of the hover and low-speed lateral axis handling qualities, especially for the case without the automatic flight control system. In addressing the observed mismatch, the gains of the longitudinal and lateral components of the inflow model were selected to be significantly higher than their theoretical values. In this study, a detailed understanding of the rotor-to-rotor inflow interference is pursued using a recently developed multi-rotor pressure potential superposition inflow model. It is shown that the coupling between the inflow gradients of individual rotors exists in a tandem rotor, which can be approximated by using higher values for the longitudinal and lateral inflow gains of individual rotors. Further, it is shown that the need for empirical tuning of aerodynamic hub moment influence factors can be eliminated by properly accounting for the rotor-to-rotor interference in the inflow model.

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Applied low cost 'real time' flight simulation code generation in an aeronautial engineering curriculum

10.2514/6.1998-4534 ◽

1998 ◽

Author(s):

Douglas Hiranaka ◽

Eric Vinande ◽

Douglas Cameron ◽

Daniel Biezad

Keyword(s):

Real Time ◽

Code Generation ◽

Low Cost ◽

Flight Simulation ◽

Engineering Curriculum ◽

Simulation Code

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Mathematical Modelling of Gimballed Tilt-Rotors for Real-Time Flight Simulation

Aerospace ◽

10.3390/aerospace7090124 ◽

2020 ◽

Vol 7 (9) ◽

pp. 124

Author(s):

Anna Abà ◽

Federico Barra ◽

Pierluigi Capone ◽

Giorgio Guglieri

Keyword(s):

Mathematical Model ◽

Real Time ◽

Flight Control ◽

Flight Simulation ◽

The Novel ◽

Handling Qualities ◽

Tilt Rotor ◽

Research Activities ◽

New Formulation ◽

The Mathematical Model

This paper introduces a novel gimballed rotor mathematical model for real-time flight simulation of tilt-rotor aircraft and other vertical take-off and landing (VTOL) concepts, which improves the previous version of a multi-purpose rotor mathematical model developed by ZHAW and Politecnico di Torino as part of a comprehensive flight simulation model of a tilt-rotor aircraft currently implemented in the Research and Didactics Simulator of ZHAW and used for research activities such as handling qualities studies and flight control systems development. In the novel model, a new formulation of the flapping dynamics is indroduced to account for the gimballed rotor and better suit current tilt-rotor designs (XV-15, V-22, AW-609). This paper describes the mathematical model and provides a generic formulation as well as a specific one for 3-blades proprotors. The method expresses the gimbal attitude but also considers the variation of each blade’s flapping due to the elasticity of the blades, so that the rotor coning angle can be represented. A validation of the mathematical model is performed against the available literature on the XV-15 Tilt-rotor aircraft and a comparison between the previous model is provided to show the improvements achieved. The results show a good correlation between the model and the reference data and the registered performance allow real-time flight simulation with pilot and hardware in the loop.

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