On the maximisation of control power in low-speed flight

2019 ◽  
Vol 123 (1266) ◽  
pp. 1099-1121
Author(s):  
L. M. B. C. Campos ◽  
J. M. G. Marques
Keyword(s):  
Control Surface ◽  
Pitching Moment ◽  
Multiple Control ◽  
Rolling Moment ◽  
Yaw Control ◽  
Control Power ◽  
Moment Coefficient ◽  
Engine Failure ◽  
Surface Deflections ◽  
Control Surfaces

ABSTRACTThe maximisation of control power is considered for an aircraft with multiple control surfaces, with the force and moment coefficients specified by polynomials of the control surface deflections of degree two. The optimal deflections, which maximise and minimise any force or moment coefficient, are determined subject to constraints on the range of deflection of each control surface. The results are applied to a flying wing configuration to determine: (i/ii) the pitch trim, at the lowest drag for the fastest climb, and at the highest drag for the steepest descent; (iii) the maximum and minimum pitching moment; (iv) the maximum and minimum yaw control power and the fraction needed to compensate an outboard engine failure for several propulsion configurations; (v) the maximum and minimum rolling moment. The optimal use of all control surfaces has significant advantages over using just one, e.g. the range of drag modulation with pitch trim is much wider and the maximum and minimum available control moments larger.

Lift Engine Bleed Flow Management for a V/STOL Fighter Reaction Control System

1973 ◽  
Author(s):  
C. N. Webster
Keyword(s):  
Control System ◽  
Performance Characteristics ◽  
Flow Management ◽  
Yaw Control ◽  
Control Power ◽  
Aerodynamic Control ◽  
Management Concept ◽  
Control Surfaces ◽  
Selection Of ◽  
Reaction Control System

In a lift-plus-lift/cruise V/STOL fighter, reaction control may be used to provide pitch, roll and yaw control power during hover and low speed flight when aerodynamic control surfaces are ineffective. This power is provided by reaction jets in the pitch, roll and yaw axes. Reaction thrust is derived from lift engine bleed air. This paper discusses the trade studies leading to the selection of a reaction control system arrangement and a bleed air management concept. The selected system, its performance characteristics, and flow management are discussed.

Transient Response Study on Rolling Effectiveness of Multiple Control Surfaces

2002 ◽  
Author(s):  
Deman Tang ◽  
Aiqin Li ◽  
Earl H. Dowell
Keyword(s):  
Transient Response ◽  
Three Dimensional ◽  
Wind Tunnel Test ◽  
Leading Edge ◽  
Control Surface ◽  
Multiple Control ◽  
Wing Model ◽  
Aerodynamic Model ◽  
Control Surfaces ◽  
Dry Friction Damping

In the present paper, a transient response study of the effectiveness of trailing and leading edge control surfaces has been made for a rolling wing-fuselage model. An experimental model and wind tunnel test are used to assess the theoretical results. The theoretical model includes the inherently nonlinear dry friction damping moment that is present between the spindle support and the experimental aeroelastic wing model. The roll trim equation of motion and the appropriate aeroelastic equations are solved for different combinations of leading and trailing edge control surface rotations using a reduced order aerodynamic model based upon the fluid eigenmodes of three dimensional vortex lattice aerodynamic theory. The present paper provides new insights into the transient dynamic behavior and design of an adaptive aeroelastic wing using trailing and leading edge control surfaces.

Design criteria for conceptual sizing of primary flight controls

2004 ◽  
Vol 108 (1090) ◽  
pp. 629-641 ◽  
Author(s):  
A. J. Steer
Keyword(s):  
Quality Criteria ◽  
Emergency Operation ◽  
Operating Conditions ◽  
Control Surface ◽  
Normal Operation ◽  
Civil Aviation ◽  
Design Criteria ◽  
Bank Angle ◽  
Control Power ◽  
Engine Failure

Abstract The European Supersonic Commercial Transport’s control surface configuration is based largely on Concorde’s and has been scaled to provide comparable un-augmented stability and manoeuvre performance. Hence, optimising the surface size could provide significant performance benefits in terms of reduced drag, noise, structural and actuator power requirements. Adequate control power will be required to meet current civil aviation regulations whose primary aim is to ensure the aircraft can be flown safely during both normal and emergency operation. Additional design criteria, combined with the optimum longitudinal control laws, are required to ensure desirable handling qualities with minimum pilot workload. Two critical low-speed flight conditions, normal and emergency, together with associated aircraft configurations for control surface sizing have been identified. The rudder must provide sufficient control power to achieve positive heading changes subsequent to a double asymmetric engine failure during normal operation. The fin should be sized to satisfy Dutch roll stability criteria with the un-augmented aircraft in its emergency configuration. The dual functionality of the elevons require that they are sized using both pitch and roll performance and handling quality criteria. The bank angle capture requirement provides the most critical elevon design case, the satisfaction of which also ensures adequate pitch control power. Validation using ‘pilot-in-the-loop’ simulation will be required whilst more explicit control surface size optimisation would require the definition of limiting airspeeds and operating conditions applicable to the European Supersonic Commercial Transport. Additional studies of control power requirements during transonic and supersonic cruise may also be required.

scholarly journals Aeroelastic simulations of a delta wing with a Chimera approach for deflected control surfaces

2021 ◽  
Author(s):  
Christopher Reinbold ◽  
Kaare Sørensen ◽  
Christian Breitsamter
Keyword(s):  
Flow Field ◽  
Delta Wing ◽  
Dynamic Pressure ◽  
Computational Effort ◽  
Control Surface ◽  
Navier Stokes ◽  
Moment Coefficient ◽  
Computational Structural Mechanics ◽  
Aeroelastic Simulations ◽  
Control Surfaces

AbstractA numerical tool for the computation of aircraft control surface aerodynamics with flexibility effects is presented. The solution is based on coupled Computational Fluid Dynamics (CFD) and Computational Structural Mechanics (CSM) simulations embedded in the multidisciplinary simulation environment SimServer. In SimServer, the DLR-TAU Code is utilized to obtain the CFD solution by solving the Reynolds-Averaged Navier–Stokes (RANS) equations. Structural displacements are computed with a modal solver. The Chimera implementation of SimServer, suited for hybrid grids, is applied to model the control surfaces. Numerical simulations with the flexible Chimera method are performed for the Model53 wing configuration, which is a generic delta wing with a deployed slat as well as an inboard and outboard trailing edge flap. Aerodynamic and aeroelastic simulations at high dynamic pressure $$q=45$$ q = 45  kPa and transonic speed $${\text {Ma}} = 0.8$$ Ma = 0.8 are performed for several angles of attack $$10^\circ \le \alpha \le 25^\circ$$ 10 ∘ ≤ α ≤ 25 ∘ and flap deflection angles $$-30^\circ \le \delta \le 30^\circ$$ - 30 ∘ ≤ δ ≤ 30 ∘ . The effect of structural deformations on the flow field and control surface effectiveness are analyzed and compared to computations of components treated fully rigid. At the targeted freestream condition $$M=0.8$$ M = 0.8 and $${\text {Re}}=15.1 \times 10^7$$ Re = 15.1 × 10 7 , the flow field around the Model53 configuration is characterized by the interaction of vortices and shock waves. The results of the lift and pitching moment coefficient for the rigid and flexible configuration revealed the importance of taking the structural flexibility into account in order to obtain more accurate results for the considered range of flap deflections. Furthermore, the computational effort of the aerodynamic and aeroelastic simulations are evaluated. The increase in computational effort is shown to be adequate for the given increase in accuracy.

scholarly journals Wind Tunnel Tests of the Tu-154M Aircraft Aerodynamic Characteristics

2019 ◽  
Vol 26 (3) ◽  
pp. 113-120
Author(s):  
Andrzej Krzysiak
Keyword(s):  
Wind Tunnel ◽  
Aerodynamic Characteristics ◽  
Full Scale ◽  
Control Surface ◽  
Rolling Moment ◽  
Wind Tunnel Tests ◽  
Aircraft Model ◽  
University Of Technology ◽  
The Military ◽  
Control Surfaces

Abstract Determination of possible manoeuvres to be performed by the aircraft requires knowledge of its aerodynamic characteristics including, in particular, characteristics of the aircraft at configuration with deflected control surfaces. In this article, the wind tunnel tests results of the model of passenger Tu-154M aircraft manufactured at the scale 1:40 are presented. The model was designed and manufactured by the Military University of Technology based on the Tu-154M aircraft geometry obtained by full-scale object scanning. The model mapped all aircraft control surfaces, along with the gaps between these surfaces and the main wing part. During the tests all the model’s control surface like, flaps, ailerons, spoilers, slots, rudder, elevator and tail plane were deflected at the same deflection angles range as they are used in the full scale aircraft. The aerodynamic characteristics of the tested Tu-154M aircraft model were measured by the 6-component internal balance. Based on the obtained measurements the aircraft model aerodynamic coefficients were calculated. In the article the basic aerodynamic characteristics of the tested Tu-154M aircraft model i.e. lift, drag coefficients as well as pitching, yawing and rolling moment coefficients versus model angles of attack and sideslip angles were presented. The tests were performed in the Institute of Aviation low speed wind tunnels T-1 of the 1.5 m diameter test section at the undisturbed velocity, V∞ = 40 m/s.

REDUCED-ORDER-MODEL-BASED PLACEMENT OPTIMIZATION OF MULTIPLE CONTROL SURFACES FOR ACTIVE AEROELASTIC CONTROL

2014 ◽  
Vol 11 (06) ◽  
pp. 1350081 ◽  
Author(s):  
GANG CHEN ◽  
XIAN WANG ◽  
YUEMING LI
Keyword(s):  
Optimization Method ◽  
Reduced Order Model ◽  
Control Surface ◽  
Limit Cycle Oscillation ◽  
Control Performance ◽  
Order Model ◽  
Multiple Control ◽  
Reduced Order ◽  
Placement Optimization ◽  
Control Surfaces

The application of multiple control surfaces is a potential method in active aeroelastic control. The placement of a control surface has great impact on the aeroelastic control performance. How to determine the placement of a control surface is a very important task in active controller design. Based on the proper orthogonal decomposition method, an aeroservoelastic reduced order model suitable for placement optimization in transonic flow was developed. Then a two-step aeroelastic optimization method based on the genetic algorithm was proposed to search the optimal placements of control surfaces. The modified Goland+ wing configuration with four aerodynamic control surfaces was applied to demonstrate the proposed placement optimization method. The simulation results show that the optimized configuration improves the aeroelastic control performance obviously and suppresses the limit cycle oscillation successfully with good performance.

scholarly journals Numerical Simulation of the Aerodynamic Influence of Aircrafts During Aerial Refueling with Engine Jet

2019 ◽  
Vol 21 (1) ◽  
pp. 15-24 ◽  
Author(s):  
Yi Li ◽  
Yang Zhang ◽  
Junqiang Bai
Keyword(s):  
Stokes Equations ◽  
Dynamic Pressure ◽  
Lift Coefficient ◽  
Jet Flow ◽  
Aerodynamic Characteristics ◽  
Navier Stokes ◽  
Pitching Moment ◽  
Aerial Refueling ◽  
Rolling Moment ◽  
Moment Coefficient

Abstract Aerial refueling technology has been widely applied in various fields and it is one of the hotspots but difficulties for the aeronautical technologies. DLR-F6 WBNP model is used as a tanker and a fighter model is used as a receiver. The flow field of Probe–Drogue refueling and Flying Boom refueling is numerically simulated using the Reynolds-averaged Navier–Stokes equations, and the effects of the jet flow and the aerodynamic characteristics of the receiver are taken into consideration. The results indicate that the effect of downwash of the tanker reduces the lift coefficient and decreases the pitching moment coefficient of the receiver. The jet flow of tanker increases the dynamic pressure while decreases the local angle of attack, which increases the pressure difference between the upper and lower surfaces of receiver. Compared with the results without jet, the jet flow can increase the lift and the drag of the receiver and reduces the pitching moment, and even cause the change of rolling moment direction. Therefore, engine jet is an important factor when simulating aerial refueling.

Time-Accurate Simulation of Longitudinal Flight Mechanics with Control by CFD/RBD Coupling

2012 ◽  
Vol 226-228 ◽  
pp. 788-792 ◽  
Author(s):  
Dong Guo ◽  
Min Xu ◽  
Shi Lu Chen
Keyword(s):  
Computational Study ◽  
Rigid Motion ◽  
Rigid Body Dynamics ◽  
Flight Mechanics ◽  
Control Surface ◽  
Free Flight ◽  
Body Dynamics ◽  
Computational Fluid Dynamics Cfd ◽  
Coupled Solution ◽  
Surface Deflections

This paper describes a multidisciplinary computational study undertaken to compute the flight trajectories and simultaneously predict the unsteady free flight aerodynamics of aircraft in time domain using an advanced coupled computational fluid dynamics (CFD)/rigid body dynamics (RBD) technique. This incorporation of the flight mechanics equations and controller into the CFD solver loop and the treatment of the mesh, which must move with both the control surface deflections and the rigid motion of the aircraft, are illustrated. This work is a contribution to a wider effort towards the simulation of aeroelastic and flight stability in regions where nonlinear aerodynamics, and hence potentially CFD, can play a key role. Results demonstrating the coupled solution are presented.

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