FIN (GRID) operation in Missile & Rockets

A mini project presentation on

FIN OPERATION OF MISSILES AND ROCKETS

presented by

RAM PRATHAP SINGH K.SAI KRISHNA (13D45A0312) (12D41A0347)

SRI INDU COLLEGE OF ENGG & TECH.

TABLE OF CONTENT

1. INTRODUCTION

2. FIN OR GRID FIN

3. WORKING OF FIN

4. COMPONENTS

5. TYPES OF FIN

6. APPLICATION

7. ADVANTAGES AND DISADVANTAGES

8. CONCLUSION

INTRODUCTION

Grid fins, also known as lattice fins, proposed by Belotzerkovsky et al. They consist of an outer frame which supports an inner lattice of intersecting planar surfaces. Unlike planar fins, grid fins are aligned perpendicular to the flow field to allow the air to pass through the lattice of grid cells. The truss structure formed by the lattice fins is inherently strong, which allows the lattice walls to be extremely thin, reducing the weight and cost. One of the main advantages of grid fins is that, due to their shorter chord lengths, at higher speeds, they generate lower hinge moments than planar wings requiring smaller actuators to rotate them. Additionally, the smaller chord and cascade-like flow reduces the likelihood of stall at high angles of attack relative to conventional planar fins offering increased control effectiveness. To this point, grid fins have found numerous uses on missiles and other endeavors.

WHAT IS A FIN

A model rocket must have fins or stabilizing surface on its rear end in order to fly properly. The fins on the model rocket like feathers on an arrow. They keep the model going straight in the air. The fin is not to provide lift forces but it is a stabilizing device to ensure a safe and predictable flight. Different fins design will produce different center of pressure. The fin designs are usually streamlined airfoil or rounded because it nearly doubled the performance and the altitude. Some of the fins are made of from the balsa wood. Nowadays, they use a plastic fins so the fin would not broken when the rocket are landing.

WORKING PRINCIPLE

WORKING PRINCIPAL

The mechanism is based on both

Pneumatic & Hydraulic system.

A Pneumatic system consists of 3.5 liters of air in the bottle. To the air bottle a Casual Tee is connected at one side and the other two sides are connected to the pyro valves by the help pneumatic pipe lines. Casual Tee is used to reduce required pressure to the system.

WORKING PRINCIPLE

On pneumatic pipe line an ACU (An actuator is a type of motor that is responsible for moving or controlling a mechanism or system) and PT are connected.

A Pyrotechnic valve is a one time use propulsion component often used to control propellant or pressurant system.

A functional port is fixed in between pyro valves. It is used for checking any leakages. Pneumatic system is connected to the hydraulic system.

WORKING PRINCIPAL

A Pyrotechnic valve is a one time use propulsion component often used to control propellant or pressurant system.

A functional port is fixed in between pyro valves. It is used for checking any leakages. Pneumatic system is connected to the hydraulic system.

WORKING PRINCIPLE

Hydraulic system is connected to both Casual Tee & FDV (Filling and Draining valve). One end of the hydraulic line is connected to the casual tee where the pneumatic carried out and also reduce the pressure at required level. And the other end of the hydraulic is connected to FDV. When pressure develop in the hydraulic chamber it pushes the hydraulic oil into FDV by the help of hydraulic pipe line. The FDV is a pressure-operated valve that automatically fills the tubing as it is run in hole and other side it has draining valve which remove the oil from the hole. The FDV is connected to the compressor & oil discharge. Compressor is used to operate the fins when the fin get operated it begin to left the fin system and get locked to it. The other end is connected to the open discharge if any oil pressure is increased its get discharge.

COMPONTENTS OF FUFM

1) Actuator

2) Compensator

3) Filling and Draining valve

4) Cover assembly

5) ACU and Pyro valve

6) Hydraulic pipe assembly & Pneumatic pipe assembly

7) FDV assembly

ACTUATOR

An actuator is a type of motor that is responsible for moving or controlling a mechanism or system.

It is operated by a source of energy, typically electric current, hydraulic fluid pressure, or pneumatic pressure, and converts that energy into motion. An actuator is the mechanism by which a control system acts upon an environment. The control system can be simple (a fixed mechanical or electronic system), software-based (e.g. a printer driver, robot control system), a human, or any other input.

COMPENSATOR

Compensator can refer to: Pressure control on a piston pump

Filling and Draining valve (FDV)

▪ The FDV is a pressure-operated valve that automatically fills the tubing as it is run in hole and other side it has draining valve which remove the oil from the hole.

PYRO VALVE

A Pyrotechnic valve is a one time use propulsion component often used to control propellant or pressurant systems on spacecraft. The device is activated by an electric signal, to fire a small explosive charge which in turn shears away a small flange that initially blocked the flow path of the attached tubing. Another version of a pyrotechnic valve remains in an open position until activated. The pressure from the pyrotechnic charge then forces the flange into a weakened part of the attached tube to block the flow path of the tubing.

TYES OF FINS

1. Rectangular

2. Swept

3. Tapered

4. Delta

5. Clipped delta

6. Trapezoidal

7. Swept delta

8. Raked

TYES OF FINS

ADVANTAGES OF FUFM

1. Increase the control effectiveness.

2. To provide enhanced dynamic stability and control capability.

3. With their ability to fold along the munitions body which makes storage and transportation.

4. They have become attractive for weapons designed for internal weapon bays on stealth aircraft.

5. Include high strength-to-weight ratio.

6. Reducing the size of the control actuator systems.

7. Fins can be owed mainly to their better performance at high Mach numbers and high angles of attack.

8. Fins as efficient tail control surfaces

CONCLUSION

The research concluded that the fins performed better at high Mach numbers and high angles of attack than the conventional planar fin. Moreover, they had the advantage of lower hinge moment and higher lift. The lower hinge moment also led to the use of smaller servo motors hence reducing the size of the tail assembly. These performance parameters showed better control effectiveness of grid fins on air-to-air missiles, as a missile usually flies at high supersonic speeds. The size of the grid fin can also be reduced to compensate for the higher drag. The size can be reduced in such a manner that the control force/hinge moment which was very low for the grid fin may be kept in a specific range to maneuver the missile effectively.