Development and Assessment of CFD Methods for Integrated Simulation of Air Vehicle Stability and Control

The mechanics of a trailer system moving up and down sloping ground under different operating conditions was theoretically simulated. A computer program was developed to analyze the system to predict the effect of both the trailer loading weight and the slope angle on the off-road vehicle stability, traction ability, and drawbar loading. The results of this analysis showed that the off-road vehicle becomes unstable when towing a 3750 kg trailer uphill at 28° slope angle. Insufficient traction occurred at slope angles ranging from 15° to 18° corresponding to trailer weight of 3750 to 750 kg. The parallel component of drawbar pull reached a maximum value of (17318) N when the trailer was pushing the off-road vehicle downhill at 30° slope angle. The normal component (normal to the tractive surface) showed similar maximum values for both uphill and downhill motions of the system. The use of computer analysis in this study provided a significant improvement in predicting the effect of different parameters on stability and control of off-road vehicle-trailer combination on sloping ground.Keywords: Stability, Traction, Sloping ground, Drawbar.

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Vehicle Stability and Control Research for U.S. Comprehensive Truck Size and Weight (TS & amp;W) Study

10.4271/982819 ◽

1998 ◽

Cited By ~ 3

Author(s):

Philp W. Blow ◽

John H. Woodrooffe ◽

Peter F. Sweatman

Keyword(s):

Vehicle Stability ◽

Stability And Control ◽

Control Research ◽

Truck Size And Weight ◽

And Control

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Preliminary Static Aeroelastic Analysis of Reusable Launch Vehicle Stability and Control Derivatives

Journal of Spacecraft and Rockets ◽

10.2514/2.3434 ◽

1999 ◽

Vol 36 (1) ◽

pp. 67-74 ◽

Cited By ~ 2

Author(s):

Thomas A. Zeiler ◽

David McGhee ◽

Joseph A. Brunty

Keyword(s):

Launch Vehicle ◽

Vehicle Stability ◽

Stability And Control ◽

Reusable Launch Vehicle ◽

Aeroelastic Analysis ◽

Control Derivatives ◽

And Control

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Computational Study of the Flight Dynamics, Stability and Control of an Unmanned Aerial Vehicle in an Integrated Simulation Framework

AIAA Atmospheric Flight Mechanics Conference and Exhibit ◽

10.2514/6.2008-6563 ◽

2008 ◽

Author(s):

Leon CS Tan ◽

M. Damodaran

Keyword(s):

Unmanned Aerial Vehicle ◽

Computational Study ◽

Flight Dynamics ◽

Simulation Framework ◽

Integrated Simulation ◽

Stability And Control ◽

Aerial Vehicle ◽

And Control ◽

Dynamics Stability

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Rotor Blade Wake Flutter—A Comparison of Theory and Experiment

Journal of the American Helicopter Society ◽

10.4050/jahs.21.2.32 ◽

1976 ◽

Vol 21 (2) ◽

pp. 32-43 ◽

Cited By ~ 3

Author(s):

William D. Anderson ◽

George A. Watts

Keyword(s):

High Frequency ◽

Mode Coupling ◽

Unsteady Aerodynamics ◽

Specific Region ◽

Vehicle Stability ◽

Main Rotor ◽

Stability And Control ◽

Design Changes ◽

Bladed Rotor ◽

And Control

During early whirl testing of the hingeless main rotor of the AH‐56A Cheyenne helicopter, a high‐frequency (7P), highly coupled, flap‐torsion‐inplane flutter occurred at rotor overspeed at a condition of near zero lift at the rotor tips. The flutter disappeared at higher and lower values of rotor lift rather than being nearly lift independent as had been predicted by quasisteady aerodynamic theory. Wake flutter was suspected and coroborated by subsequent analysis. This discussion covers the theoretical flutter analyses and the effects on flutter of design changes made both to eliminate the flutter and to improve vehicle stability and control. A theoretical analysis employing quasi‐steady aerodynamics was the basis for predicting the complicated reactionless interblade mode shape and frequency, but not the lift level of instability. The flutter stability analysis was then amended to include the effects of previous blade passage wakes and interblade mode coupling, in the four‐bladed rotor, on unsteady aerodynamics and the new analysis results agreed very well with the experimental flutter. The flutter was shown to occur in the specific region of lift near zero, being stable at higher and lower levels, and at a critical overspeed rpm with stability reappearing with increase of rpm above the critical.

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