Identification of gyroplane lateral/directional stability and control characteristics from flight test

1998 ◽  
Vol 212 (4) ◽  
pp. 271-285 ◽  
Author(s):  
S S Houston
Keyword(s):  
High Speed ◽  
Degrees Of Freedom ◽  
Flight Test ◽  
Accident Rate ◽  
Stability And Control ◽  
Directional Stability ◽  
Control Derivatives ◽  
Limited Application ◽  
And Control ◽  
Rotary Wing

This paper presents an analysis of test data recorded during flight trials of a gyroplane. This class of rotary-wing aircraft has found limited application in areas other than sport or recreational flying. However, the accident rate is such that a study of the configuration's stability and control characteristics is timely, and in addition substantive data are required for a new airworthiness and design standard that is under development. The paper complements previous work on the longitudinal degrees of freedom and, as a consequence, serves to consolidate the understanding of gyroplane stability and control. The identified derivatives are related to specific aspects of the layout of the gyroplane, and hence the influence of design on the static and dynamic behaviour is quantified. It is concluded that robust estimates of the lateral and directional stability and control derivatives have been identified. This analysis has focused on ‘high-speed’ flight, and the identified derivatives highlight benign and ‘conventional’ characteristics in this part of the flight envelope.

An investigation of the flight dynamic characteristics of gyroplanes by use of flight tests

2004 ◽  
Vol 108 (1088) ◽  
pp. 531-535
Author(s):  
V. M. Spathopoulos
Keyword(s):  
Flight Test ◽  
Accident Rate ◽  
Simulation Data ◽  
Stable Mode ◽  
Stability And Control ◽  
Centre Of Gravity ◽  
Limited Application ◽  
The Stability ◽  
And Control ◽  
Rotary Wing

AbstractAn analysis is presented both of flight test and simulation data obtained from a gyroplane aircraft. This class of rotary-wing vehicle has found limited application in areas other than recreational flying, however the accident rate has been such that it has prompted the study of the configuration’s stability and control characteristics. It is concluded that the flight dynamic response of the gyroplane examined is dominated by a fast, non-stable mode, affecting all states and thus increasing pilot workload. Simulation results indicate that the position of the centre of gravity significantly influences the stability of this mode.

Rotorcraft Lateral-Directional Oscillations: The Anatomy of a Nuisance Mode

2021 ◽  
Author(s):  
Dheeraj Agarwal ◽  
Linghai Lu ◽  
Gareth D. Padfield ◽  
Mark D. White ◽  
Neil Cameron
Keyword(s):  
Simulation Model ◽  
Simulation Models ◽  
Flight Test ◽  
Flight Simulation ◽  
Stability And Control ◽  
Systems Research ◽  
Control Derivatives ◽  
Research Aircraft ◽  
Level Of Understanding ◽  
And Control

High-fidelity rotorcraft flight simulation relies on the availability of a quality flight model that further demands a good level of understanding of the complexities arising from aerodynamic couplings and interference effects. One such example is the difficulty in the prediction of the characteristics of the rotorcraft lateral-directional oscillation (LDO) mode in simulation. Achieving an acceptable level of the damping of this mode is a design challenge requiring simulation models with sufficient fidelity that reveal sources of destabilizing effects. This paper is focused on using System Identification to highlight such fidelity issues using Liverpool's FLIGHTLAB Bell 412 simulation model and in-flight LDO measurements from the bare airframe National Research Council's (Canada) Advanced Systems Research Aircraft. The simulation model was renovated to improve the fidelity of the model. The results show a close match between the identified models and flight test for the LDO mode frequency and damping. Comparison of identified stability and control derivatives with those predicted by the simulation model highlight areas of good and poor fidelity.

Spinning gasodynamic projectile system identification experiment design

2020 ◽  
Vol 92 (3) ◽  
pp. 452-459 ◽  
Author(s):  
Piotr Lichota ◽  
Mariusz Jacewicz ◽  
Joanna Szulczyk
Keyword(s):  
System Identification ◽  
High Speed ◽  
Content Type ◽  
Stability And Control ◽  
Novel Approach ◽  
Control Derivatives ◽  
Designed Experiment ◽  
Regions Of Stability ◽  
Short Time ◽  
And Control

Purpose The purpose of this paper is to present the methodology that was used to design a system identification experiment of a generic spinning gasodynamic projectile. For this object, because the high-speed spinning motion, it was not possible to excite the aircraft motion along body axes independently. Moreover, it was not possible to apply simultaneous multi-axes excitations because of the short time in which system identification experiments can be performed (multi-step inputs) or because it is not possible to excite the aircraft with a complex input (multi-sine signals) because of the impulse gasodynamic engines (lateral thrusters) usage. Design/methodology/approach A linear projectile model was used to obtain information about identifiability regions of stability and control derivatives. On this basis various sets of lateral thrusters’ launching sequences, imitating continuous multi-step inputs were used to excite the nonlinear projectile model. Subsequently, the nonlinear model for each excitation set was identified from frequency responses, and the results were assessed. For comparison, the same approach was used for the same projectile exited with aerodynamic controls. Findings It was found possible to design launching sequences of lateral thrusters that imitate continuous multi-step input and allow to obtain accurate system identification results in specified frequency range. Practical implications The designed experiment can be used during polygonal shooting to obtain a true projectile aerodynamic model. Originality/value The paper proposes a novel approach to gasodynamic projectiles system identification and can be easily applied for similar cases.

scholarly journals ESTIMATION OF THE LATERAL AERODYNAMIC COEFFICIENTS FOR SKYWALKER X8 FLYING WING FROM REAL FLIGHT-TEST DATA

2018 ◽  
Vol 58 (2) ◽  
pp. 77
Author(s):  
Rahman Mohammadi Farhadi ◽  
Vyacheslav Kortunov ◽  
Andrii Molchanov ◽  
Tatiana Solianyk
Keyword(s):  
Test Data ◽  
Flight Test ◽  
Least Square ◽  
Stability And Control ◽  
Information Parameter ◽  
Control Derivatives ◽  
Aerial Vehicle ◽  
Aerodynamic Parameters ◽  
Priori Information ◽  
And Control

Stability and control derivatives of Skywalker X8 flying wing from flight-test data are estimated by using the combination of the output error and least square methods in the presence of the wind. Data is collected from closed loop flight tests with a proportional-integral-derivative (PID) controller that caused data co-linearity problems for the identification of the unmanned aerial vehicle (UAV) dynamic system. The data co-linearity problem is solved with a biased estimation via priori information, parameter fixing and constrained optimization, which uses analytical values of aerodynamic parameters, the level of the identifiability and sensitivity of the measurement vector to the parameters. Estimated aerodynamic parameters are compared with the theoretically calculated coefficients of the UAV, moreover, the dynamic model is validated with additional flight-test data and small covariances of the estimated parameters.

Paper 2. Problems and Requirements of Directional Stability, Control and Manoeuvrability; High-Speed Craft

1972 ◽  
Vol 14 (7) ◽  
pp. 6-13
Author(s):  
M. C. Eames
Keyword(s):  
High Speed ◽  
Stability Control ◽  
Paper Briefly ◽  
Planing Craft ◽  
Stability And Control ◽  
Directional Stability ◽  
Air Cushion ◽  
And Control ◽  
Air Cushion Vehicles

The problems of stability and control of high-speed craft are somewhat different for the various vehicle types. The first part of this paper briefly compares characteristics of air-cushion vehicles and planing craft. This is followed by a more detailed discussion of the problems and requirements of hydrofoil craft.

scholarly journals Vertical tail sizing of propeller-driven aircraft considering the asymmetric blade effect

2021 ◽  
pp. 095441002110294
Author(s):  
Mohsen Rostami ◽  
Joon Chung ◽  
Daniel Neufeld
Keyword(s):  
Significant Contribution ◽  
Incident Angle ◽  
Empirical Methods ◽  
Handling Qualities ◽  
Stability And Control ◽  
Directional Stability ◽  
Control Derivatives ◽  
The Stability ◽  
Semi Empirical ◽  
And Control

An engineering approach is presented to analyse the asymmetric blade thrust effect with the help of analytical and semi-empirical methods. It is shown that the contribution of the asymmetric blade thrust effect in the lateral-directional stability of multi-engine propeller-driven aircraft is significant particularly in critical flight conditions with one engine out of service. Also, in some cases where the engines are rotating in one direction, the asymmetric blade effect has substantial effects on the handling qualities of the aircraft even in normal flight conditions. Overall, due to the significant contribution of this phenomenon in the lateral-directional stability of propeller-driven airplanes, it is important to consider it in the design of the vertical stabilizer and rudder. The resulting analytical method has been used to determine the vertical tail incident angle and desired rudder deflection in accordance with the most critical flight condition for two different cases and validated to ensure the accuracy of the result. In this work, the aerodynamic coefficients as well as the stability and control derivatives have been predicted using analytical and semi-empirical methods validated for light aircraft.

Flight dynamics and parametric modeling of a 2-DOF lab aircraft

2018 ◽  
Vol 233 (8) ◽  
pp. 2923-2931
Author(s):  
Yasir Mahmood Khan ◽  
Sarvat M Ahmad ◽  
Mohsin Ali ◽  
Masroor Khan
Keyword(s):  
Degrees Of Freedom ◽  
Theoretical Models ◽  
Parametric Modeling ◽  
Loop Control ◽  
Stability And Control ◽  
Visualization Software ◽  
Control Derivatives ◽  
Data Acquisition Card ◽  
Real Time Visualization ◽  
And Control

This paper presents two degrees-of-freedom (2-DOF) modeling of a lab aircraft extending corresponding author’s previous work on 1-DOF. The yaw motion is an additional DOF introduced along with the earlier work on pitch plane alone. The test-rig is designed, developed, instrumented, and interfaced with PC employing data acquisition card and real-time visualization software. Detailed mathematical models from first principles are developed incorporating important stability and control derivatives. The theoretical models are iteratively improved and validated through experimentation. The comparison reveals close agreement between math models and experimental ones. The developed high-fidelity models are to be employed for closed-loop control design and evaluation of system performance.

Lateral and Directional Stability and Control in Air-to-Air Refuelling

1995 ◽  
Vol 209 (4) ◽  
pp. 299-305 ◽  
Author(s):  
A W Bloy ◽  
M Jouma'a
Keyword(s):  
Equations Of Motion ◽  
Flight Test ◽  
Vertical Position ◽  
Lattice Method ◽  
Vortex Lattice Method ◽  
Stability And Control ◽  
Directional Stability ◽  
Free Air ◽  
And Control ◽  
Dutch Roll

Application of a wake roll-up method coupled with the vortex lattice method and approximate expressions for the receiver fuselage effect have been used to determine the induced loads on a Hercules receiver aircraft behind a KC10 tanker. The induced loads depend strongly on the vertical position of the receiver wing and fin relative to the tanker wing wake. In the case of steady sideslip there is a large decrease in the directional stability of the receiver as quantified by the gradient of the rudder angle versus sideslip. This is due mainly to the combined effects of the yawing moments due to bank, yaw and side displacements. Minimum directional stability corresponds to the tip of the receiver fin intersecting the tanker wing wake. The associated aileron angle is two to three times the value in free air in agreement with flight test data. Solution of the linearized equations of motion gives three lateral characteristic oscillations for the air-to-air refuelling case. These include the usual Dutch roll oscillation, a highly damped rolling oscillation and a divergent oscillation involving mainly bank and side displacements.

scholarly journals Method for designing multi-input system identification signals using a compact time-frequency representation

2021 ◽  
Author(s):  
Mathias Stefan Roeser ◽  
Nicolas Fezans
Keyword(s):  
System Identification ◽  
Design Method ◽  
Flight Test ◽  
Compact Representation ◽  
Time Frequency ◽  
Stability And Control ◽  
Frequency Representation ◽  
Aerodynamic Parameters ◽  
Definition Of ◽  
And Control

AbstractA flight test campaign for system identification is a costly and time-consuming task. Models derived from wind tunnel experiments and CFD calculations must be validated and/or updated with flight data to match the real aircraft stability and control characteristics. Classical maneuvers for system identification are mostly one-surface-at-a-time inputs and need to be performed several times at each flight condition. Various methods for defining very rich multi-axis maneuvers, for instance based on multisine/sum of sines signals, already exist. A new design method based on the wavelet transform allowing the definition of multi-axis inputs in the time-frequency domain has been developed. The compact representation chosen allows the user to define fairly complex maneuvers with very few parameters. This method is demonstrated using simulated flight test data from a high-quality Airbus A320 dynamic model. System identification is then performed with this data, and the results show that aerodynamic parameters can still be accurately estimated from these fairly simple multi-axis maneuvers.

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