scholarly journals Shifts in stability and control effectiveness during evolution of Paraves support aerial maneuvering hypotheses for flight origin

2014 ◽  
Author(s):  
Dennis Evangelista ◽  
Sharlene Cam ◽  
Tony Huynh ◽  
Austin Kwong ◽  
Homayun Mehrabani ◽  
...  
Keyword(s):  
Hind Wing ◽  
Static Stability ◽  
Physical Models ◽  
Power Stroke ◽  
Major Influence ◽  
Stability And Control ◽  
Control Effectiveness ◽  
Aerodynamic Control ◽  
Aerial Platforms ◽  
And Control

The capacity for aerial maneuvering was likely a major influence on the evolution of flying animals. Here we evaluate consequences of paravian morphology for aerial performance by quantifying static stability and control effectiveness of physical models for numerous taxa sampled from within the lineage leading to birds (Paraves). Results of aerodynamic testing are mapped phylogenetically to examine how maneuvering characteristics correlate with tail shortening, fore- and hind-wing elaboration, and other morphological features. In the evolution of Paraves we observe shifts from static stability to inherently unstable aerial platforms; control effectiveness also migrated from tails to the forewings. These shifts suggest that some degree of aerodynamic control and and capacity for maneuvering preceded the evolution of strong power stroke. The timing of shifts also suggests features normally considered in light of development of a power stroke may play important roles in control.

scholarly journals Shifts in stability and control effectiveness during evolution of Paraves support aerial maneuvering hypotheses for flight origin

2014 ◽  
Author(s):  
Dennis Evangelista ◽  
Sharlene Cam ◽  
Tony Huynh ◽  
Austin Kwong ◽  
Homayun Mehrabani ◽  
...  
Keyword(s):  
Hind Wing ◽  
Static Stability ◽  
Physical Models ◽  
Power Stroke ◽  
Major Influence ◽  
Stability And Control ◽  
Control Effectiveness ◽  
Aerodynamic Control ◽  
Aerial Platforms ◽  
And Control

The capacity for aerial maneuvering was likely a major influence on the evolution of flying animals. Here we evaluate consequences of paravian morphology for aerial performance by quantifying static stability and control effectiveness of physical models for numerous taxa sampled from within the lineage leading to birds (Paraves). Results of aerodynamic testing are mapped phylogenetically to examine how maneuvering characteristics correlate with tail shortening, fore- and hind-wing elaboration, and other morphological features. In the evolution of Paraves we observe shifts from static stability to inherently unstable aerial platforms; control effectiveness also migrated from tails to the forewings. These shifts suggest that some degree of aerodynamic control and and capacity for maneuvering preceded the evolution of strong power stroke. The timing of shifts also suggests features normally considered in light of development of a power stroke may play important roles in control.

scholarly journals Shifts in stability and control effectiveness during evolution of Paraves support aerial maneuvering hypotheses for flight origin

2014 ◽  
Author(s):  
Dennis Evangelista ◽  
Sharlene Cam ◽  
Tony Huynh ◽  
Austin Kwong ◽  
Homayun Mehrabani ◽  
...  
Keyword(s):  
Static Stability ◽  
Morphological Features ◽  
Physical Models ◽  
Power Stroke ◽  
Major Influence ◽  
Stability And Control ◽  
Control Effectiveness ◽  
Aerodynamic Control ◽  
And Control

ABSTRACTThe capacity for aerial maneuvering was likely a major influence on the evolution of flying animals. Here we evaluate consequences of paravian morphology for aerial performance (Dudley and Yanoviak, 2011; Smith, 1952) by quantifying static stability and control effectiveness of physical models (Evangelista et al., 2014) for numerous taxa sampled from within the lineage leading to birds (Paraves, Xu et al., 2011; Gauthier and Padian, 1985). Results of aerodynamic testing are mapped phylogenetically (Maddison and Maddison, 2010; Zhou and Li, 2010; Li et al., 2010; O’Connor et al., 2011; Cracraft et al., 2004) to examine how maneuvering characteristics correlate with tail shortening, fore-and hindwing elaboration, and other morphological features. In the evolution of Paraves we observe shifts from static stability to inherently unstable aerial planforms; control effectiveness also migrated from tails to the forewings. These shifts suggest that some degree of aerodynamic control and and capacity for maneuvering preceded the evolution of strong power stroke. The timing of shifts also suggests features normally considered in light of development of a power stroke may play important roles in control.

scholarly journals Aerodynamic Characteristics of a Feathered Dinosaur Measured Using Physical Models. Effects of Form on Static Stability and Control Effectiveness

PLoS ONE ◽  
2014 ◽  
Vol 9 (1) ◽  
pp. e85203 ◽  
Author(s):  
Dennis Evangelista ◽  
Griselda Cardona ◽  
Eric Guenther-Gleason ◽  
Tony Huynh ◽  
Austin Kwong ◽  
...  
Keyword(s):  
Aerodynamic Characteristics ◽  
Static Stability ◽  
Physical Models ◽  
Stability And Control ◽  
Control Effectiveness ◽  
And Control

scholarly journals Aerodynamic characteristics of a feathered dinosaur measured using physical models. Effects of form on static stability and control effectiveness.

2013 ◽  
Author(s):  
Dennis Evangelista ◽  
Griselda Cardona ◽  
Eric Guenther-Gleason ◽  
Tony Huynh ◽  
Austin Kwong ◽  
...  
Keyword(s):  
Flight Control ◽  
Angle Of Attack ◽  
Aerodynamic Characteristics ◽  
Static Stability ◽  
Physical Models ◽  
Stability And Control ◽  
Control Effectiveness ◽  
Biomechanical Constraints ◽  
Lift And Drag ◽  
And Control

We report the effects of posture and morphology on the static aerodynamic stability and control effectiveness of physical models based on the feathered dinosaur,Microraptor gui, from the Cretaceous of China. Postures had similar lift and drag coefficients and were broadly similar when simplified metrics of gliding were considered, but they exhibited different stability characteristics depending on the position of the legs and the presence of feathers on the legs and the tail. Both stability and the function of appendages in generating maneuvering forces and torques changed as the glide angle or angle of attack were changed. These are significant because they represent an aerial environment that may have shifted during the evolution of directed aerial descent and other aerial behaviors. Certain movements were particularly effective (symmetric movements of the wings and tail in pitch, asymmetric wing movements, some tail movements). Other appendages altered their function from creating yaws at high angle of attack to rolls at low angle of attack, or reversed their function entirely. WhileM. guilived afterArchaeopteryxand likely represents a side experiment with feathered morphology, the general patterns of stability and control effectiveness suggested from the manipulations of forelimb, hindlimb and tail morphology here may help understand the evolution of flight control aerodynamics in vertebrates. Though these results rest on a single specimen, as further fossils with different morphologies tested, the findings here could be applied in a phylogenetic context to reveal biomechanical constraints on extinct flyers arising from the need to maneuver. Now published in PLOS ONE http://dx.plos.org/10.1371/journal.pone.0085203

Some Stability and Control Aspects of Airframe/Propulsion System Interactions on the YF-12 Airplane

1974 ◽  
Vol 96 (3) ◽  
pp. 820-826 ◽  
Author(s):  
D. T. Berry ◽  
G. B. Gilyard
Keyword(s):  
Static Stability ◽  
Propulsion System ◽  
Jet Propulsion ◽  
Stability And Control ◽  
The Stability ◽  
And Control ◽  
Large Aircraft

Airframe/propulsion system interactions can strongly affect the stability and control of supersonic cruise aircraft. These interactions generate forces and moments similar in magnitude to those produced by the aerodynamic controls, and can cause significant changes in vehicle damping and static stability. This in turn can lead to large aircraft excursions or high pilot workload, or both. For optimum integration of an airframe and its jet propulsion system, these phenomena may have to be taken into account.

Estimation of Lateral/Directional Static Stability Characteristics of a Turboprop Aircraft at one Engine Inoperative Condition

2016 ◽  
Vol 842 ◽  
pp. 208-216 ◽  
Author(s):  
Ratna Ayu Wandini ◽  
Taufiq Mulyanto ◽  
Hari Muhammad
Keyword(s):  
Short Distance ◽  
Fuel Efficiency ◽  
Aircraft Design ◽  
Static Stability ◽  
Slip Angle ◽  
High Fuel Efficiency ◽  
Stability And Control ◽  
Conceptual Design Phase ◽  
The Stability ◽  
And Control

Twin engines turboprop aircraft provides the most beneficial solution to meet the needs of short distance flight due to high fuel efficiency [1]. One of the emergency conditions which has to be considered for this type of the aircraft when one engine is out operating or one engine inoperative because it involves the safety of flight. Furthermore, a safe flight with one engine inoperative is regulated by FAR/CASR Part 25 and has to be complied during certification .Stability and control characteristics of a turboprop aircraft will change significantly if one engine inoperative condition occurs during cruise phase. The rudder and/or aileron deflections to counter the yawing and rolling moments due to the thrust of the operating engine must satisfy. Recognizing the importance of that consideration, this research will estimate the stability and control characteristics of lateral/directional in one engine inoperative condition on new turboprop 80-pax aircraft design concept.This paper presents procedures for estimating the lateral/directional static stability characteristics of a 80-pax turboprop aircraft during the conceptual design phase. The size of the rudder and aileron have to be iterated to fullfil the requirements at a condition when one engine is not operative. The rudder and the aileron deflections are estimated as functions of airspeed, roll angle, side slip angle and thrust setting. It will be shown in this paper that the required rudder deflection as well as aileron deflection can satisfy to balance the forces and moments due to asymmetrical thrust condition and the minimum control speed of the aircraft can be maintained as well.

scholarly journals OPTIMAL DESIGN OF MICROGRID IN AN AUTONOMOUS MODE USING ANTCOLONY OPTIMIZATION

2013 ◽  
pp. 14-18
Author(s):  
N. CHITRA ◽  
TAMIZHARASI. G ◽  
A. SENTHIL KUMAR
Keyword(s):  
Time Domain ◽  
Power Sharing ◽  
Time Domain Simulation ◽  
Stability And Control ◽  
Control Effectiveness ◽  
Damping Characteristics ◽  
Autonomous Mode ◽  
The Stability ◽  
And Control ◽  
Nonlinear Time Domain

The dynamic nature of the distribution network challenges the stability and control effectiveness of the microgrid in autonomous mode. In this paper, nonlinear model of microgrid operating in autonomous mode has been presented. The controller parameters and power sharing coefficients are optimized in case of autonomous mode. The control problem has been formulated as an optimization problem where Ant colony optimization is employed to search for optimal settings of the optimized parameters. In addition, nonlinear time-domain-based objective function has been proposed to minimize the error in the measured power and to enhance the damping characteristics, respectively. Finally, the nonlinear time-domain simulation has been carried out to assess the effectiveness of the proposed controllers under different disturbances and loading conditions. The results show satisfactory performance with efficient damping characteristics of the microgrid considered in this study.

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