Showing papers on "Rudder published in 1993"

Rudder-Roll Damping Autopilot Robustness to Sway-Yaw-Roll Couplings

Abstract: Roll damping and simultaneous heading control by means of rudders has certain robustness problems. This has been experienced in practice, where a controller performed quite differently on sister ships where the only differences were changes in appendages and loading condition. Analysis of the rudder-roll damping autopilot problem is difficult, primarily due to its complexity, second because hydrodynamic couplings are sparsely treated in the literature. In this work, symbolic mathematical manipulation is introduced to analyze the hydrodynamic equations and provide relations between hydrodynamic parameters and control dynamics. Based on this, an assessment of structured uncertainty is given that can be used for robust design of RRD/course control systems. The main emphasis is on the effects of coupling terms which have not been thoroughly analyzed before. It is shown that changes in the coupling terms can change the roll damping ability significantly. The effects of uncertainty within given bounds are illustrated on an RRD-course controller using data from a naval multipurpose vessel.. It is shown that realistic changes of coupling terms and other uncertainty can give important changes to linear control dynamics and that these changes can make significant changes to both roll reduction and stability margin. Contributions of the paper are to advise ways to access the effects of coupling term changes on RRD control, to show the changes in robustness, including roll reduction capability for various parameters, and to provide a complete, parameterized model that can be used for comparison of methodology in RRD design.

Forebody vortex control - A progress review

Abstract: Conventional fighter aircraft control surfaces, such as the rudder, become ineffective at high angles of attack resulting in a serious deficiency in lateraldirectional controllability in the angle of attack range for maximum lift and in the post stall regime. Development of robust control methods for high angle of attack flight has focused primarily on thrust vector control and forebody vortex control. This paper is an attempt to review the forebody vortex control research that has taken place in the last two to three years. Some earlier research results are also shown to provide a historical perspective and to document the state of our knowledge of this rapidly advancing technology. The techniques that have been investigated include large deployable or hinged strakes, pneumatic techniques using either nozzles or slots, suction through small holes or ports, and miniaturized rotatable nose-tip and nose-boom strakes. Optimized versions of all of these techniques are effective in producing primarily yawing moments at high AOA, with, for some configurations, some interactions in rolling moment. Mass flow rates required for pneumatic techniques are at levels that can be obtained from today's engine bleed systems. Application of techniques developed for conventional forebodies with rounded cross sections are just beginning to be evaluated for advanced forebodies with chined cross sections.

Remote controlled decoy

Abstract: A remotely controlled floating decoy having a buoyant body resembling a game bird and having a receiver disposed within the buoyant body. The receiver is responsive to commands from a transmitter and provides electrical control signals to a plurality of servomechanisms and associated linkages in response to the commands. The apparatus also has a propulsive device coupled to the buoyant body and electrically coupled to the receiver. The propulsive device is responsive to the electrical control signals. The apparatus also has a rudder coupled to a rear end of the buoyant body. The rudder is responsive to the electrical control signals. The propulsive device and the rudder cooperate to provide directed locomotion for the buoyant body in response to commands transmitted from the transmitter.

Some aspects of a realistic three-dimensional pursuit-evasion game

Abstract: A three-dimensio nal pursuit-evasion game between a realistic missile and an aircraft is studied employing point-mass models for both vehicles. Since a direct method to solve this complicated mini-max problem is too time-consuming, the study is conducted by carrying out massive simulations in the parameter space of initial conditions and guidance law parameters. The important role of information in the opponent's acceleration to the game and the effectiveness of the strategy in rotating the line-of-sight vector are shown. It is found that there exist very few cases where the aircraft can avoid the missile, among them typical air-combat maneuvers such as linear acceleration, high-£ barrel roll, split-S, and horizontal-S. Nomenclature flcmax = missile lateral acceleration command limit Ompjdmy = missile acceleration components measured in aircraft pitch and yaw axis, respectively ^p^y^pc^yc = missile-pitch and yaw-axis lateral accelerations and their command signals OpttOyt = aircraft-desir ed pitch and yaw acceleration components, respectively Otp9oty = aircraft acceleration components measured in missile pitch and yaw axis, respectively CD = drag coefficient CDO

Friction reducing surface and devices employing such surfaces

Abstract: An improved aerodynamic surface for the exterior of vehicles moving through a gas and vehicles employing such improved surfaces. The improved surface comprises a matrix of dimples or depressions formed into the portions of the surface of the vehicle. The improved surface is most beneficially located either at a leading edge, where the vehicle first cleaves the pool of air through which it is traveling, or on vehicle surfaces which tend to move the air pool to accommodate the presence of the vehicle itself or on vehicle surfaces to which the designer wishes to provide a lift function. Wings, ailerons and rudder surfaces are examples of surfaces to which a lift function is most applicable. The vehicle may be of the nature of an automobile, a boat or an airplane. The invention is also applicable to the internal surface of pipes for conveying fluid.

Wind tunnel investigation of the influence of propeller loading on ship rudder performance

Abstract: A detailed investigation has been carried out into the interaction between a ship rudder and propeller combination. The tests used the 11' x 8' low speed wind tunnel at the University of Southampton. This report presents results for a series of three all-movable rudders with the same mean chord of 667mm and NACA0020 sections, but with varying aspect ratio and taper ratio. A four-bladed, 800mm diameter, adjustable pitch propeller was used. This propeller is a modified version of the Wageningen B4.40 series. Open-water results for the modified design were validated against published data. The test consisted of a series of parametric studies into the effect of the longitudinal distance between the propeller and rudder, propeller thrust loading, rudder aspect ratio, and rudder taper ratio. A five-component strain-gauge dynamometer was used to measure lift, drag and three moments on the rudder and a rotating strain gauge dynamometer the developed thrust and torque of the propeller. In addition, both spanwise and chordwise pressure distributions were measured on the rudder surface. Propeller revolutions were varied between 0 and 3,000 rpm and tunnel wind speeds up to 20m/s were used. Results are presented in the form of non-dimensional coefficients of lift (C subscript L), drag (C subscript D), spanwise (CP subscript S) and chordwise (CP subscript C) position of the centre of pressure variation with incidence for the rudder. The influence of rudder on propeller performance is given in terms of non-dimensional thrust (K subscript T) and torque (K subscript Q) coefficient variation with advance ratio (J). The surface pressure measurements on the rudder are presented as both a spanwise distribution of the local lift coefficient (C subscript L) and as a surface pressure distribution. Principal findings of the work were that: increasing propeller thrust loading increased rudder sideforce while delaying stall. For constant rpm the presence of the rudder alters the propellers developed thrust and torque characteristic. Changes in the longitudinal separation of the rudder and propeller had only a minimal effect on the sideforce characteristics of the rudder. The information presented should be of considerable use in numerically modelling the flow interaction and in the development of more advanced ship manoeuvring simulations.

Thrust vectoring free wing aircraft

Abstract: The VTOL aircraft (10) includes a free wing (16) having wings on opposite sides of the fuselage (12) connected to one another for joint free rotation and for differential pitch settings under pilot, computer or remote control. On vertical launch, pitch, yaw and roll control is effected by the elevators (26), rudder (24) and the differential pitch settings of the wings, respectively. At launch, the elevator (26) pitches the fuselage (12) nose downwardly to alter the thrust vector and provide horizontal speed to the aircraft whereby the free wing (16) rotates relative to the fuselage (12) into a generally horizontal orientation to provide lift during horizontal flight. Transition from horizontal to vertical flight is achieved by the reverse process and the aircraft may be gently recovered in or on a resilient surface such as a net (66).

Shape-memory-actuated compliant control surface

Abstract: Advanced submarine stern configurations require a variety of control surfaces to actively manage aftbody boundary layer flow, vorticity, propulsor inflow and intrapropulsor flow, as well as vehicle attitude. Two necessary attributes of advanced control surface designs include (1) integrated actuation to provide placement flexibility at remote locations with minimal structural interfacing and control interconnects, and (2) improved lift efficiency and flow using variable or adaptive camber control. To demonstrate these attributes, a shape memory alloy (SMA) actuated compliant control fin (CCF) with a planform area of 620 sq. cm was developed for evaluation as rudder and sternplane appendages on a radio control submarine model at velocities up to 5.1 m/s (Reynolds No. approximately equals 1,000,000) and up to 0.2 Hz full cycle actuation. A completely fixed root design was developed to reduce turbulence at the hull/fine interface, with compliant deformation of the foil to improve flow characteristics over the baseline full-flying and trailing-edge-flap designs.

Autopilot having an adaptive deadband feature

Abstract: A marine autopilot having a deadband feature to reduce ineffectual rudder movement and unnecessary wear on the rudder and associated drive apparatus. In a first deadband operation, four deadband values are computed based on various parameters in order to provide optimum system performance and circuit redundancy. The deadband values are a function of the maximum allowable heading error, the maximum allowable angular velocity of the vessel, and the vessel speed. A second deadband operation compensates for noise introduced into the autopilot system by the speed sensor, compass, and roll sensor.

Actuated Forebody Strake Controls for the F-18 High-Alpha Research Vehicle

Abstract: A series of ground-based studies have been conducted to develop actuated forebody strake controls for flight test evaluations using the NASA F-18 High-Alpha Research Vehicle. The actuated forebody strake concept has been designed to provide increased levels of yaw control at high angles of attack where conventional rudders become ineffective. Results are presented from tests conducted with the flight-test strake design, including static and dynamic wind-tunnel tests, transonic wind-tunnel tests, full-scale wind-tunnel tests, pressure surveys, and flow visualization tests. Results from these studies show that a pair of conformal actuated forebody strakes applied to the F-18 HARV can provide a powerful and precise yaw control device at high angles of attack. The preparations for flight testing are described, including the fabrication of flight hardware and the development of aircraft flight control laws. The primary objectives of the flight tests are to provide flight validation of the groundbased studies and to evaluate the use of this type of control to enhance fighter aircraft maneuverability.

Process for the control of the control surfaces of an aircraft for the low speed compensation of a lateral path deviation

Abstract: The present invention relates to a process for the automatic control of the control surfaces of an aircraft for the low speed compensation of a lateral path deviation, in which beyond a given deflection threshold (20) of the deflected rudder (17), there is a control of a deflection, proportional to the exceeding of the threshold, of the wing surfaces (13, 14) of one of the two wings (18), said wing being that on the side of the deflected rudder (17), so as to provide a drag supplement to said wing and therefore yaw on the aircraft Application to the take-off of large civil transport aircraft

Stopped rotor aircraft utilizing a flipped airfoil X-wing

Abstract: This invention is directed to stopped rotor Flipped Airfoil X-wing (FAX-WING.sup.™) aircraft which comprises: (a) A rotary wing flight mode which operates similar to a helicopter, wherein all main rotor airfoils rotate with leading edges into the oncoming airstream (neglecting forward motion) to provide lift, and utilize an anti-torque rotor to cancel main rotor torque. The fixed wing flight mode, including supersonic flight, utilizes all stationary main rotor airfoils for primary lift, such that all airfoil leading edges are positioned forward, meeting the oncoming airstream generated by forward aircraft motion. Two airfoils are forward swept 45 degrees, and the other two airfoils are aft swept 45 degrees. The transition mode for converting from rotary wing to fixed wing flight, and vise-versa, causes two adjacent airfoils to flip 180 degrees (in approximately 1/16 second) about their pitch axis, such that all airfoils have leading edges in the correct orientation for a particular flight mode. (b) Rotating flywheel inertia mass(es) capable of being coupled to the main rotor airfoils, via a flywheel clutch, for the purpose of rapidly starting or stopping airfoil angular rotation (in approximately 1 second) without applying adverse torque to the aircraft fuselage, and a spin up/spin down mechanism for applying angular momentum to the flywheel inertia mass(es) at gradual rates such that the anti-torque rotor and/or rudder can cancel torque. (c) Computer based flight control system capable of directing rotary wing, fixed wing, and transition therebetween. (d) Variable pitch ducted fan to provide forward thrust, coupled to common turboshaft engine(s), that also provide power to the main rotor.

Forebody vortex control with jet and slot blowing on an F/A-18

Abstract: A wind tunnel test program was conducted in October, 1992, on a 6-percent F/A-18 model, to determine the most effective methods of forebody vortex control for providing increased yaw control at high angles of attack. A series of circular jet blowing configurations were investigated with variations in blowing rate, fuselage station, circumferential position, and blowing angle. Slot configurations were also tested and included variations in blowing rate, forward fuselage station, and length. The optimum jet and slot configurations were then also tested at -10 deg of sideslip. Yawing moments from both the jet and slot blowing configurations were found to have very good trends with increasing blowing rates and the maximum yaw control available at 50-deg angle of attack (where rudder power had dropped to near zero) was found to be 40 percent greater than the level provided by the rudder at 0-deg angle of attack.

Ball and socket bearing assembly for a rudder post

Abstract: A ball and socket assembly adapted to engage the post of a rudder installed in the stern of a boat and to maintain it at a proper upright position regardless of the degree to which the post deviates from the vertical and is subjected to hydrodynamic forces which seek to displace the post. The assembly consists of a journal box fixedly mounted on a support and having a spheroidal cavity, and a bearing through which the rudder post extends. The bearing is constituted by a spheroidal section that nests within the cavity of the box and a cylindrical section projecting from the box and pinned to the post whereby the bearing is in alignment with the post and its spheroidal section is caused to rotate within the cavity in accordance with the rotation of the post as the boat is steered.

Multi-axial hand-operated aircraft control and method

Abstract: A multi-axial hand-operated helicopter control includes a pivotal arm which may freely pivot in two planes relative to a base member with collective and rudder control rods attached at the base of the pivoting arm member for translating motion along one plane into collective control and motion along another plane into rudder control. A rotatable throttle control mounts at an end of the arm member and a throttle shaft extends through the arm member attaching to a constant velocity joint for translating rotational movement of the throttle control into rotational movement of a base throttle rod. The pivotal arm member is mounted to a base member via a universal joint, with the constant velocity joint placed at the center of the universal joint, achieving high torque rotation. A method of operating a helicopter in accordance with the invention includes controlling the helicopter collective via movement of the control arm in a vertical plane, controlling the rudder of the helicopter through movement of the control arm in a horizontal plane and adjusting the engine throttle via a throttle handle mounted on the arm member. Foot controls for the helicopter are eliminated.

Full envelope multivariable control law synthesis for a high-performance test aircraft

Abstract: A full envelope multivariable flight control system is developed for the Variable Stability In-Flight Simulator Test Aircraft (VISTA). Separate control laws are designed for the longitudinal and lateral directional axes. Output feedback controllers with integral error feedback are created using linear quadratic synthesis and simple linear transformations. Longitudinal stick inputs are used to generate an angle-of-attack command at low-dynamic pressure and a normal acceleration command at high-dynamic pressure. Lateral stick inputs are used to generate a stability axis roll rate command, and rudder pedal inputs are used to generate a sideslip command. Linear point designs are integrated into a gain schedule to create a full envelope nonlinear control system. Flying qualities are evaluated according to military standards and shown to be satisfactory for a wide operating envelope. Classical gain and phase margins and analysis of the structured singular value show robustness to be acceptable for a wide operating envelope.

Twisted rudder for a vessel

Abstract: Ship rudders are subjected to propeller induced velocities and induced flow angles that vary along the rudder span and chord. Because of non-zero onset flow angles, a suction pressure peak is formed at or near the leading edge of the rudder where early cavitation occurs. The present invention is directed to a rudder and method for minimizing early cavitation and related ship vibration and for thus improving acoustic and hydrodynamic performance thereof. The rudder of the present invention is twisted so as to have profiles along its entire span that are aligned with propeller induced non-zero onset flow angles into the rudder plane. The twist of the rudder sections vary in the spanwise direction, that is, the twist angle of one rudder sections may vary relative to the twist angle of adjacent or remaining rudder sections, such that the rudder experiences substantially zero angles of attack along the span.

A Note on the Applicability of Rudder Roll Stabilisation for Ships

Abstract: This paper considers the question posed by ship operators and designers as to whether a Rudder Roll Stabilisation (RRS) system is justified for a particular ship, and aims to avoid the situation where a ship operator commissions an in depth study into the procurement of suitable hardware and software without being able to assess whether the approach is suitable for the ship in question. The paper proposes a method whereby ship operators can assess the suitability of an RRS System for their ships based on data which can be obtained from a number of simple ship trials.

Disk spoiler system

Abstract: Spoilers, mounted on vertical stabilizer tail surfaces of large aircraft release controllable Bernoulli forces to augment rudder and aileron aircraft controls. Data from surface pressure sensors, also mounted on vertical stabilizer tail surface, is computer-interpreted to minimize tail drag and structural flight-stress. The spoilers suitable for this role include parallel lines of controllable height barriers, located on the fore part of each side of symmetrical airfoils of airplane tails.

Trim compensation for a hovercraft

Abstract: Trim compensation for a hovercraft having two engines (2,3) with flow outlet apertures. The two engines (2,3) are arranged laterally at the stern of the hovercraft to generate air jets for forward motion. The hovercraft also includes a compressor to generate an air cushion beneath the hovercraft. The trim compensation includes a tail plane arrangement located in the air jets in the two engines for directional control of the hovercraft by deflection of the air jets. The tail plane arrangement consists of a negatively arranged V-plane (7) with a middle upper section from which extends stabilizer surfaces (9,10) at both sides in a downward direction. The stabilizer surfaces (9, 10) are provided with rudder elements (11, 12) which are swingable in the same or opposite direction to deflect the air jets. The stabilizer surfaces (9, 10) and the rudder elements (11, 12) run centrally across the flow outlet apertures of the engines (2, 3). The rudder elements (11, 12) are swivelled about an axis of rotation in addition to the directional control to produce an additional force component for trim compensation which is generated by the additional deflection of the air jets of the two engines (2, 3) and which is constantly superimposed on the directional control.

Rudder blades for medium and large sized ships

Abstract: The rudder assembly has a rudder blade (1) movable around a post (2), both made of composite materials.The lower part of the post is of polygonal cross-section, to engage in a ceasing (4) of the corresponding section in the body of the rudder.The polygonal design prevents relative rotation of the post and rudder. The casing is attached to the rest of the rudder by a joint surface extending completely over one of its faces.

Prediction of ship rudder-propeller interaction using parallel computations and wind tunnel measurements

Abstract: A theoretical method has been developed to predict the forces developed due to the interaction between a ship rudder and propeller. A parallel lifting suface panel program (PALISUPAN) ha sbeen written in Occam2 which is designed to run across variable sized square arrays of transputers. thsi program forms teh basis of the theoretical method. The rudder and propeller are modelled separately. Their interaction is accounted for through an iterative process whereby their respective inflow velocity fields are modified using a circumferential average of the disturbance velcoity due to the other body. Prior to writing PALISUPAN, software techniques for the implementation of computational fluid dynamics algorithms across arrays of transputers were developed. The approach used is based on a geometric parallelism. At the outermost level on each transputer the particular CFD algorithm runs in parallel with a harness process. The harness controls teh communication across teh transputer array. to prove thsi concept an explicit finite volume solver for the two-dimensional Euler equations has been implemented. PALISUPAN itself uses a perturbation potential formulation and an explicit zero pressure loading condition is enforced at the trailing edge. Use of the communications harness greatky reduces code development time and although an implicit solver PALISUPAN gives good parallel performance. Wind tunnel tests were undertaken to derive experimental data for validation of the prediction method. These used a 3.5m x 2.5m low speed widn tunnel and a range of flow an dgeometrical parameters were tested. Total rudder forces and moments, propeller thrust and torque and quasi-steady rudder surface pressures were measured. Empirical relationships for teh prediction of rudder lift, drag and stall for use in ship manoeuvring studeis were also derived. The validated theoretical prediction for rudder-propeller interaction using PALISUPAN allows the detailed design of sjip rudder-propeller systems to be enhanced. The parallel performance of the pALISUPAN demonstrates the practicality of using transputer arrays to solve CFD problems.

Wind tunnel tests on the influence of propeller loading on ship rudder performance: four quadrant operation, low and zero speed operation

Abstract: The results of wind tunnel tests on a rudder operating downstream of a propeller are presented The experiments simulated the condition of a rudder operating in the proximity of a propeller but without the influence of the hull The tests were carried out in the 35m x 25m wind tunnel at the University of Southampton and form an extension to the basic rudder-propeller tests which have already been carried out and are reported on elsewhere The rudders tested were all movable, and the propeller used in the tests was modelled on a Wageningen B440 Tests were carried out with positive and negative wind speed and positive and negative propeller revolutions in order to simulate all the four quadrants of operation These tests also included the case of zero and low wind speed Results are presented as rudder lift, drag and moment coefficients and centre of pressure for selected angles of attack and changes in propeller thrust loading Surface pressure distributions over the rudder were also obtained in selected cases in order to provide a detailed knowledge of the distribution of forces over the rudder The results provide rudder force data for use in manoeuvring simulations and detailed data for the validation of numerical modelling of the interaction problem

Estimation of aerodynamic derivatives using Dynamic Wind Tunnel Simulation Technique

Abstract: This paper presents the results of estimation of the longitudinal and lateral aerodynamic derivatives of a delta winged aircraft model using Dynamic Wind Tunnel Simulation Technique. Experiments are conducted using single rotary degree freedom in pitch, roll, and yaw axes. Test inputs are applied to the appropriate servo controlled control surfaces namely symmetric elevon, differential elevon, and rudder to excite the model in pitch, roll, and yaw respectively. The characteristic motion response of the model to the applied test inputs is analyzed using parameter estimation techniques to extract the aerodynamic derivative data. The results are compared with derivatives obtained from conventional testing methods namely static wind tunnel test, free oscillation rig, and forced oscillation rig which use force/moment data obtained from the model strain gauge balance. A recently developed method of computing neutral point using parameter estimation technique is used to determine the same for this model. (Author)

The method for predicting the performance of propeller-rudder system with rudder angle and its application to the rudder design

Abstract: In this paper the performance of the system of a propeller and a rudder with rudder angle behind a ship is treated hydrodynamically from the propulsion and manoeuvring viewpoint. The propeller and the rudder behind a ship are regarded as a unit to generate the thrust and the lateral force, which is named PRS (Propeller-Rudder- System). In order to calculate the performance characteristics of PRS, for simplicity, the simplified propeller theory is applied to calculate the forces acting on the propeller, assuming an infinitely bladed propeller. The panel method in the lifting body theory is adopted to calculate the forces acting on the rudder, taking into account the friction force obtained by two dimensional boundary layer calculation. The mutual interaction is taken into consideration by superposing the induced velocity by the other on the inflow. The contraction by the simple method is introduced for the free steam of the propeller as the inflow into the rudder. When a PRS is set in uniform flow, the performance characteristics of the PRS is calculated. The calculated results of the thrust and the lateral force acting on PRS show good agreement with the experimental results. The assessment of the performance characteristics of PRS is also discussed. Finally the proposed method to calculate the performance characteristics of PRS is applied to design rudders.

Complex control device of thrust direction and steering for missile

Abstract: PURPOSE:To provide a complex control device of thrust direction and steering wherein both an aerodynamic rudder and a thrust deflection blade are unitarily controlled by means of a single control device. CONSTITUTION:An aerodynamic rudder 2, a thrust deflection means 3 for changing the direction of a nozzle jet flow, and a complex control means 4 for unifiedly controlling the aerodynamic rudder 2 and the thrust deflection means 3 are provided for constructing a complex control device of the thrust direction and steering for a missile.

Steering gear for a hovercraft

Abstract: The invention relates to a steering device for a hovercraft having at least one engine to drive it and a compressor to provide an air-cushion which can be generated below the craft, and in which there is a rudder device at the stern to control the direction of travel. The aim of the invention is to provide a steering device for a hovercraft providing a substantial improvement in taking a curve course and a considerable reduction in the radii of curvature in all speed ranges. According to the invention, the engines (2; 3) are fitted with a jet deflection device and the jet of air emerging from the engines (2; 3) can be deflected by said device when a curving course is taken in such a way as to produce a force component about the transverse axis of stability countering centrifugal force. The jet deflection device of the invention consists of a rudder system with a negative Vee arrangement in the form of a Vee stream deflector (7).

Boat rudder control system

Abstract: A rudder control system for a boat rudder comprises a rudder control line extending from the tiller to guide spools displaced from the center line of the hull. The ends of the control line are joined by a resilient section which may take the form of a coil spring or resilient cord. Stop means affixed to the control line and the boat hull resiliently return the rudder to the center position. Adjustment of the tension in the cord provides for resistance to turning movement of the rudder.

Paternoster tackle for fishing

Abstract: PURPOSE:To obtain a fishing paternoster tackle floating near the sea bottom or water bottom to prevent the snagging in underwater obstruction by providing a vertical rudder plate and a side wing plate. CONSTITUTION:The paternoster tackle is provided with a fixed or swivellable vertical rudder plate 4 and a mobile side wing plate 5. As an alternative, the tackle is provided with a mobile vertical rudder plate and a mobile side wing plate. When the tackle is thrown into seawater or water, it is directed in a definite direction relative to the tidal flow or water flow by the vertical rudder plate and a floating force is generated by the side wing plate to float the tackle 1 near the sea bottom or water bottom and keep in the state. The floating force of the side wing plate assists the pulling-up of a caught fish.