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This study aims to numerically study the three-dimensional (3D) flow field characteristics in a conical convergent divergent (CD) nozzle with an internal strut system to describe the effect of struts on producing a side force for thrust vectoring applications.

Struts are solid bodies. When inserted into the supersonic region of the axisymmetric CD nozzle, it induces a shock wave that causes an asymmetric pressure distribution predominantly over the internal surface of the diverging wall of the C-D nozzle, creating a net side force similar to the secondary injection thrust vectoring control method. Numerical simulations were performed by solving Unsteady Reynolds Averaged Navier–Stokes equations with re-normalized group k–ϵ turbulence model. Cylindrical struts of various heights positioned at different locations in the divergent section of the nozzle were investigated at a nozzle pressure of 6.61.

Thrust vectoring angle of approximately 3.8 degrees was obtained using a single cylindrical strut with a dimensionless thrust (%) and total pressure loss of less than 2.36% and 2.67, respectively. It was shown that the thrust deflection direction could also be changed by changing the strut insertion location. A strut located at half of the diverging length produced a higher deflection per unit total pressure loss.

Using a lightweight and high-temperature resistant material, such as a strut, strut insertion-based thrust vectoring control might provide an alternative thrust vectoring method in applications where a longer period of control is needed with a reduced overall system weight.

This study describes the 3D flow field characteristics which result in side force generation by a supersonic nozzle with an internal strut.

A Description of the Development of the Bristol Siddeley Pegasus and Plenum Chamber Burning for the BS.100 and an Outline of the Performance of a V/S.T.O.L Subsonic Strike Fighter Utilizing a Vectored Thrust Engine with PCB as Compared with a Composite Power Plant Fighter and a Vectored Thrust Type without PCB. The Bristol Siddeley Pegasus vectored‐thrust turbo‐Tan has now been in operation for six years, and during that time has been developed to a fully operational stan‐dard in the Hawker Siddeley Kestrel V/S.T.O.L. sub‐sonic strike fighter. Initial development of a second‐generation V/ S.T.O.L. strike fighter for supersonic flight necessitated thrust augmentation by combustion in the normally cold by‐pass flow. This gave rise to the design and development of a suitable combustion system, now known as ‘Plenum Chamber Burning’, or ‘PCB’. This paper summarizes the satisfactory development of the Pegasus vectored‐thrust turbofan, gives some description of the PCB system development, and shows how the application of this system to a V/S.T.O.L. subsonic strike fighter vectored‐thrust power plant gives the latter considerable superiority when compared with an equivalent composite power plant configuration.

The purpose of this paper is to propose a high angle of attack short landing model for switched polytopic systems as well as to derive an equation for fluidic thrust vector deflection angle based on pressure to reduce the velocity during the landing phase of flight.

In this paper, robust control algorithm is proposed for a non-linear high angle of attack aircraft under the effects of non-linearities, tottering hysteresis, irregular and wing rock atmosphere. High angle of attack short landing flight under asynchronous switching is attained by using the robust controller method. Lyapunov function and the average dwell time scheme is used for obtaining the switched polytopic scheme. The asynchronous switching and loss of data are controlled asymptotically. The velocity of aircraft has been lucratively reduced during the landing phase of flight by using the robust controller technique.

The proposed algorithm based on robust controller including the effects of non-linearities guarantee the successful reduction of velocity for high angle of attack switched polytopic systems.

As the landing phase of an aircraft is one of the complicated stage, this algorithm plays a vital role in stable and short landing under the condition of high angle of attack (AOA).

In this paper, not only the velocity of flight has been reduced, but also the high angle of attack has been attained during the landing phase, because of which the duration of landing has been reduced as well, while in most of the previous research, it is based on low angle of attack and long landing duration.

The purpose of this paper is to analyze the flowfield structure and performance of dual secondary injection system for thrust vectoring in a convergent‐divergent nozzle and to compare it with a single secondary injection system.

Dual secondary injection for thrust vectoring in a convergent‐divergent nozzle is studied by solving three‐dimensional Reynolds‐averaged Navier‐Stokes equations by the means of Fluent. Realizable k‐ε turbulent model with enhanced wall‐treatment approach is used for viscous model. Density‐based solver and explicit scheme are employed in the computational model. In order to study the effect of injection location on the flowfield, distance between ports is considered as the key variable.

Results show that under some circumstances, dual secondary injection system is more effective than a single injection system with the same mass flow rate. The study shows that when the distance between two ports is 8.5 times of the injection port's diameter (or more) and in the same time the first injection port is at least 1 throat diameter far from the nozzle throat, this system will show a better performance. In addition, this system reduces the probability of bow shock impingement to the opposite wall and consequently, the side force production has less limitation.

Dual secondary injection for thrust vector control (SITVC) needs less secondary flow and therefore it makes less reduction in the primary thrust. It means that for a specific primary thrust, less mass fuel is needed which makes it more economic regarding the traditional SITVC systems.

The paper's value lies in using a three‐dimensional model to study the effect of two ports distance on SITVC performance and comparison among the performance of dual and single injections when there is an impingement.

The purpose of this paper is to design an electromechanical actuator which can inherently tolerate a stuck or loose failure without any need for fault detection isolation and reconfiguration.

Generalized design methodology for a thrust vector control application is adopted to reduce the design iterations during the initial stages of the design. An optimum ball screw pitch is selected to minimize the motor sizing and maximize the load acceleration.

A high redundancy electromechanical actuator for thrust vector control has lower self-inertia and higher reliability than a direct drive simplex configuration. This configuration is a feasible solution for thrust vector control application because it offers a more acceptable and graceful degradation than a complete failure.

Future work will include testing on actual hardware to study the transient disturbances caused by a fault and their effect on launch vehicle dynamics.

High redundancy electromechanical actuator concept can be extended to similar applications such as solid motor nozzle in satellite launch vehicles and primary flight control system in aircraft.

High redundancy actuators can be useful in safety critical applications involving human beings. It can also reduce the machine downtime in industrial process automation.

The jam tolerant electromechanical actuator proposed for the launch vehicle application has a unique configuration which does not require a complex fault detection isolation and reconfiguration logic in the controller. This enhances the system reliability and allows a simplex controller having a lower cost.

In this study, 2D density-based SST K-turbulence model with compressibility effect is used to observe the flow separation and shock wave interactions of the flow. The wall static pressure and Mach number differences are also evaluated. This study aims to discuss the aforementioned objectives

This study outlines the evaluation of the performance of a 2D convergent–divergent nozzle with various triangular jet tab configurations that can be used for effective thrust vectoring of aerial vehicles.

From the study, it is seen that the shadow effect induced by the tab with a height of 30% produces higher oblique wave deflection and higher thrust deflection at the exit nozzle. The numerical calculation concluded that thrust vector efficiency of 30% jet tab is, 0.46%. In the case of 10% jet tab height the thrust vector efficiency is higher, i.e. 1.647%.

2D study.

The optimization will open up a new focus in TVC that can be implemented for effective attitude control in aircrafts.

Used in future aircrafts.

The influence of shadowing ratio with different tab heights at different Mach numbers has not been reported in the previous studies. Few of the studies on jet tab are focused on the acoustic studies and not pertaining to the aerodynamic aspects. The multi jet configuration, the combination of location, shapes and other parametric analysis have not been covered in the previous studied.

The purpose of this study is to design a flight control model for a control surface-less (CSL) tri-tilt-rotor (TTR) unmanned aerial vehicle (UAV) based on a Proportional Integral Derivative (PID) controller to stabilize the altitude and attitude of the UAV subjected to various flying conditions.

First, the proposed UAV with a tilting mechanism is designed and analyzed to obtain the aerodynamic parameters. Second, the dynamics of the proposed UAV are mathematically modeled using Newton-Euler formation. Then, the PID controller is implemented in the simulation model to control flight maneuvers. The model parameters were implemented in a mathematical model to find the system’s stability for various flight conditions. The model was linearized to determine the PID gain values for vertical take-off and landing, cruise and transition mode. The PID controller was tuned to obtain the desired altitude and attitude in a short period. The tuned PID gain values were implemented in the PID controller and the model was simulated.

The main contribution of this study is the mathematical model and controller for a UAV without any control surface and uses only a thrust vector control mechanism which reduces the complexity of the controller. The simulation has been carried out for various flight conditions. The altitude PID controller and the attitude PID controller for CSL-TTR-UAV were tuned to obtain desired altitude and attitude within the optimum duration of 4 s and deviation in the attitude of 8%, which is within the allowable limit of 14%. The findings obtained from the simulation revels that the altitude and attitude control of the CSL-TTR-UAV was achieved by controlling the rpm of the rotor and tilt angle using the PID controller.

A novel CSL TTR UAV mathematical model is developed with a dual tilting mechanism for a tail rotor and single axis tilt for the rotors in the wing. The flight control model controls the UAV without a control surface using a PID controller for the thrust vector mechanism.

Thruster point assembly mechanism (TPAM) of the electric propulsion system allows to adjust the thrust vector, so that the thrust vector is directed to the satellite center of gravity (COG) during the satellite on-orbit working period. In this way the impact of disturbance torque caused by deviation of the thrust vector from the satellite COG during thruster ignition can be decreased. Therefore, the control accuracy of satellite is influenced directly by the control accuracy of TPAM. On the other hand, the on-orbit application of TPAM is restricted to the on-orbit computer resource. Therefore, the purpose of this paper is to design a control strategy for TPAM, and the strategy should not only be able to control the TPAM precisely but also be easily implemented by the on-board computer.

First, the structure and work principle of TPAM are discussed, and the mathematical model based on D-H coordinate system is built for it. Then the fitting methods are utilized to design the control strategy of TPAM. Absolute position fitting-based control strategy and relative position fitting-based control strategy are designed, and the least squares algorithm is introduced for parameter selection.

Simulations and tests are provided for the TPAM. Compared with the state-of-the-art PD controller, the proposed control strategy shows smaller overshoot and more simple realization. The experiment results are matched with the simulation results and both the experiment and simulation results show the validity of the proposed control strategies.

The designed control strategies can be used for the TPAM of some satellite’s electric propulsion system.

The mathematical model of the TPAM based on D-H coordinate system is given. The absolute position fitting-based control strategy and relative position fitting-based control strategy are proposed. Compared with existing methods, the two control strategies have more simple structure and smaller amount of computations. Furthermore, the relative position fitting-based control strategy achieves high precision with simple structure.

This study presents a preliminary evaluation of the application of Thrust Vectoring (TV) technology for improving windshear recovery of civil aircraft in microburst windshear encounters. A numerical trajectory optimization technique based on the method of multiple shooting is applied to achieve a microburst escape with minimal loss of altitude for a Boeing 727 type aircraft. Although the application of TV does result in a slight improvement in recovery altitude, there is also a price to be paid in the sense that TV utilization significantly hampers the ability to gain specific energy during recovery. Maintaining an energy buffer during a microburst encounter is highly desirable to achieve robustness with respect to uncertainness in windshear size and strength. TV aided windshear recovery has also been compared with an alternative approach to improve the windshear survivability capability, namely, the application of lateral maneuvering. The comparison shows that lateral maneuvering is not only a far more effective means to improve the recovery altitude, it also vastly improves energy preservation. In a view of the results established in this study, we feel that TV does not hold out great promise as a useful means to truly improve windshear recovery.

High autogyro accident rates prompted experimental investigation of this type of aircraft's low‐speed pitch characteristics. Pitch control is typically derived from main rotor tip‐path‐plane adjustment. Thus, autogyro designers often omit horizontal tails and pitch control surfaces. The purpose of this paper is to enable autogyro low‐speed pitch control by intentionally placing elevators in the propeller wake.

Wind tunnel tests were conducted on a 1:10 scale teetering rotor autogyro model. The model included a horizontal tail with elevators placed in the propeller wake. Straight‐and‐level flight conditions were estimated via a scaling scheme based on the main rotor diameter. At minimum flight speed, the pitching moment induced by 30° elevator deflection was measured. This process was repeated for a range of elevator positions behind the centre of the pitching rotation.

When placed in an autogyro propeller wake, deflected elevators induce significant pitching moments. If the elevator is shadowed from free stream flow by the autogyro cowling, the pitching moment remains unchanged regardless of the distance between elevators and centre of pitch rotation. However, if the elevator is immersed in the freestream, the pitching moment increases via deflection of both propeller wake and freestream flow.

Kinematic similarity ensures ratios between propeller wake, wind speed, and main rotor flows are representative of full scale. Without flow visualization, main‐rotor‐diameter‐based scaling does not ensure kinematic similarity. Results are therefore qualitative.

Elevators mounted in autogyro propeller wake are worthy of inclusion on all autogyros for pitch control at low speed.

Improved low‐speed pitch control arising from elevators mounted in autogyro propeller wake could potentially reduce accidents.