Why You Will Study Special Fire Control Equipment and Devices
Your study of the previous sections of these instruction sheets has undoubtedly convinced you that the job of the Fire Control Technician is one of the toughest in the Navy. And so it is-the Fire Control Technician is one of the most highly skilled men aboard Navy ships. Why must the FT acquire more skills than - say - a Sonarman, EM or IC? Well, the SO must know his ship's sonar gear inside out; the EM must be thoroughly familiar with the ship's electrical machinery and power equipment; the IC must be able to keep the interior communications systems working properly. The FT, in turn, must be able to operate and maintain all of the ship's fire control equipment. If this meant that he were responsible only for such equipment as the computers, stable elements, rangekeepers, etc., his job would not be much more involved than that of the other ratings. But the successful operation of a ship's fire control system depends to a large degree on the proper functioning of special equipment and devices associated with the system. These special equipments and devices include radar and sonar for locating and tracking the target, synchros and servo mechanisms for transmission of information and positioning equipment, and basic mechanisms for performance of computations and other operations. The FT is partly responsible for the operation and maintenance of this equipment, in addition to his strictly fire control gear. Thus you, as an FT, will have to know all about the radar, sonar, and synchros and servos used with and as integral parts of the fire control systems aboard ship.
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What You Will Study Next
The next thing you will study in your FT training course is fire control radar. To prepare you for this study you will read a section of instruction sheets, similar to these, entitled: "Fire Control Radar Fundamentals." Then "Radar Special Circuits" will explain the use of some of the special circuits found in radar equipment and you will build and test them. Following this, you will study "Synchro and Servo Fundamentals" and perform the related practical work in "Synchro and Servo Experiments" to acquaint you with these important devices before you get into the details of the specific Navy fire control equipment in which they are used. Then, after all the groundwork has been laid, you'll learn about and work with actual fire control radar.
When you conclude your work with fire control radar, you will proceed to a study of other fire control equipment. As an introduction you will study basic fire control mechanisms, and proceed from there to a detailed analysis of typical pieces of fire control equipment. Before you study antisubmarine fire control equipment, you will review the basic facts of sonar by studying "Sonar Fundamentals" and learn about various circuits peculiar to sonar by working with sonar special circuits.
This probably sounds like a big order, and indeed it is. There is still much for you to learn and plenty of work to do before you become a qualified Fire Control Technician. But keep at it, for the rewards are certainly worth the effort.
On the following sheets you will find a brief summary of the specialized subjects you will be learning in the near future.
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Introduction to "Fire Control Radar Fundamentals"
You have already been told, in previous sections of these instruction sheets, that radar is used to locate and determine the range, bearing and elevation of enemy targets. You probably also have a pretty good idea of how radar works. But the scope of Fire Control Fundamentals did not include a detailed description of the theory of radar, its capabilities, limitations and the types in use. "Fire Control Radar Fundamentals" is intended to give you an overall understanding of what radar is, what are the components of a typical system, how a radar system works, what its applications and limitations are, and what types of radar are in use. Particular emphasis is placed on the special requirements and features of radar systems specifically designed for fire control use, as opposed to radar systems designed to search large areas.
On the next sheet we will take a closer look at the various topics covered in "Fire Control Radar Fundamentals."
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Introduction to "Fire Control Radar Fundamentals" (continued)
"Fire Control Radar Fundamentals" begins with a definition of radar (Radio Detection And Ranging) and a history of its development, beginning with Maxwell's mathematical prediction of the existence of radio waves.
The major components of a typical radar system are then described and compared to equipment with which you are already familiar.
You will find a detailed explanation of how radar measures range and what various scope indications mean. You will learn about the various factors which limit the operation of radar, such as curvature of the earth, natural and man-made interference, and the nature of the object reflecting the radar signal.
The design features affecting radar operation, including the power of the transmitter, the shape of the radar beam and the length of time the transmitter is turned on are discussed in detail. How these factors compare for search and fire control radar systems is explained.
In the second half of "Fire Control Radar Fundamentals" you will review the components of a typical fire control system. You'll be told why fire control radar requires certain variations above and beyond a basic search radar system, and you'll learn about the special requirements of a fire control radar system. Then you'll analyze various antenna types and radar 'scope sweeps and see in what particular types of fire control radar systems each is employed. How fire control radar is used to track a target automatically and manually is explained, as is the use of radar for spotting the fall of shot.
Finally, to conclude your study of the fundamentals of fire control radar, you'll perform a quick analysis of a main battery and several typical antiaircraft fire control radar systems. When you finish this you will have a good understanding of the theory of radar, its applications, and the particular features, characteristics and functions of radar designed and used for fire control purposes.
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Introduction to "Synchro and Servo Fundamentals"
When you studied "Basic Electricity" at the very beginning of your course, you may recall that you saw a demonstration of a synchro system by your instructor. It may not have meant very much to you then, but, as you studied the fundamentals of fire control, you undoubtedly began to realize the importance of synchros and servos in the transmission of information between various elements of fire control systems. This application, however, is only one of a great many jobs which synchros and servos perform aboard ship. They are also used to keep the ship on a desired course, position guns, directors and radar antennas, operate recording equipment and perform calculations. If its synchro and servo systems suddenly failed to function, a ship would have a very difficult time maintaining its status as an effective weapon.
"Synchro and Servo Fundamentals" introduces you to the basic theory behind the operation of synchro and servo systems. You'll learn about synchro motors and generators, differential motors and generators, control transformers, servo motors and servo amplifiers. You'll see what jobs each of these units perform and how they work together. As you learn about these units, you will see for yourself how they work by performing the work outlined in "Synchro and Servo Experiments." Just as "Fire Control Radar Fundamentals" is intended to introduce you to radar and its specialized use in fire control, so "Synchro and Servo Fundamentals" will acquaint you with other equipment vital to the proper functioning of any fire control system-synchros and servos.
On the next sheet you will find a brief summary of the coverage of "Synchro and Servo Fundamentals."
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Introduction to "Synchro and Servo Fundamentals" (continued)
"Synchro and Servo Fundamentals" consists of seven parts as follows:
Part A-Synchro Fundamentals, explains what a synchro is and the importance of synchros. It then goes on to describe in detail the construction and basic theory of operation of synchro generators and motors and how they function as a team. The same treatment is given to synchro differential generators and motors and the control transformer-a description of their construction, theory of operation, how they are used and what function they serve in various synchro systems.
In Part B-Basic Characteristics of Servos, you'll find out what a servo is and you'll be introduced to the three basic types of servos-positioning, rate and calculating. You'll learn the basic characteristics and requirements of all servos. Then you'll see in detail how a simple servo system works by developing a servo system to replace the helmsman in keeping a ship on course. This simple analogy will teach you the fundamentals of servo systems.
Part C-Characteristics of Servo Error Detectors, Part D-Characteristics of Servo Controllers, and Part E-Servo Antihunt and Two-Speed Systems, get into the details of specialized and more complex servo mechanisms and circuits. By this time you'll have a good understanding of basic theory, and will be ready to learn the details of such things as servo amplifiers, thyratrons, the amplidyne, etc.
Finally, in conclusion, Parts F and G present an analysis of the use of servos in Navy radar and sonar systems. Here you'll see how the basic systems and special circuits you have read about are employed in actual Navy gear. Much of the material presented in Part G will be familiar to you from your study of Fire Control Fundamentals.
When you complete "Synchro and Servo Fundamentals" and have performed all of the exercises in "Synchro and Servo Experiments, " you will have a much better understanding of this special equipment which is so important to the proper functioning of a fire control system.
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Introduction to "Radar Special Circuits"
After you master the fundamental concepts of radar and synchros and servos, you will proceed in your course by reading, discussing and performing the experiments prescribed in "Radar Special Circuits." Here you will not only learn about specific circuits peculiar to radar, but you will also have a chance actually to work on these circuits by building, testing, observing operation of and troubleshooting various special radar circuits.
There are three general purposes for which special circuits are required: (1) to reshape electrical waveforms already existing in the various major components of a radar system; (2) to generate special waveforms that do not already exist in the components of the system; and (3) to connect one circuit to another in a manner which will accomplish a desired result. These three purposes can be carried out by nine basic types of circuits. These are: (1) reshaping circuits-overdriven amplifier, differentiating circuit, limiting circuit and phase inverter; (2) generating circuits-audio oscillator, blocking oscillator, multivibrator and sawtooth generator; and (3) connecting circuits-the cathode follower. These names may not mean anything to you now, but soon they will be very familiar.
Fire Control Radar Vehicular Equipment
At this point you'll be well prepared to get into the details of fire control radar. To do so, you will study fire control radar vehicular equipments which are simply typical fire control radar systems, and will serve as "vehicles" by which you will become familiar with similar equipment. As you study you will perform actual work on the equipment, so that you acquire skill in operating, maintaining and troubleshooting fire control radar equipment.
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Introduction to Fire Control Basic Mechanisms
For fire control purposes, the term "basic mechanisms" refers not only to the mechanical devices you met briefly in an earlier section of these instruction sheets, but also to various electro-mechanical and certain electronic devices used as components of fire control equipment. The electromechanical equipment combines basic mechanical devices such as gears, cams, levers, latches, cranks and differentials, with electrically operated and controlled synchros and servos. The electronic devices which will be considered as basic mechanisms for fire control purposes are those which are specifically designed to replace or work in conjunction with various mechanical devices in certain pieces of fire control equipment. Your course in fire control basic mechanisms will introduce these devices to you, explain how they work and indicate where and how they are utilized in fire control equipment.
Probably the best example of a piece of fire control equipment which depends on basic mechanisms for proper operation is the main battery fire control rangekeeper. This instrument consists almost entirely of mechanical and electro-mechanical devices, as do certain other computers. Every other fire control instrument in use-stable elements, rangefinders, directors, gun sights, etc. -depend to some extent on the proper operation of basic mechanisms of one type or another which they employ. For instance, a broken gear in a stable element can put the entire apparatus out of action.
It would not be proper to say that basic mechanisms are more vital to the proper functioning of fire control systems than radar or sonar or synchros and servos, since they are all very necessary and equally important. On the next sheet you will get a preview of your course in fire control basic mechanisms.
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Introduction to Fire Control Basic Mechanisms (continued)
In the first part of your course in fire control basic mechanisms you will learn about the basic mechanical devices used in fire control equipment. You'll see how bevel-gear and spur-gear type differentials work. You'll read about flat type and barrel cams. Then you'll get into the details of multipliers-simple screw, rack and sector types and single-cam and two-cam computing types. Various types of component solvers-cam type, screw type and vector solvers-will be discussed in detail. You'll learn about the wheel and the ball-and-roller type disk integrators. Finally, to complete your study of the strictly mechanical devices, you'll find out about various non-computing mechanisms such as intermittent drives, frictions, hand cranks, etc.
In the second part you will see what some of the most common electromechanical devices used in fire control gear are and how they work. Some of these you'll meet are solenoid signals and clutches, motor regulators, follow-up motors of several types, bearing-mounted synchros, etc.
Finally, the third part of the fire control basic mechanisms course will give you an introduction to some of the basic electronic devices which are currently being used in certain fire control instruments-notably computers-to replace mechanical devices.
Fire Control Vehicular Equipment
When you complete your work with fire control basic mechanisms you will be ready to master a detailed study of Navy fire control equipment-computers, stable elements, etc. In these studies you will work with fire control vehicular equipment just as you will have done during your study of fire control radar equipment. In this course, you will get a chance to practice operation, maintenance and troubleshooting procedures on various typical pieces of actual fire control equipment.
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Introduction to "Sonar Fundamentals"
Right now you probably know more about sonar than you do about radar or synchros and servos, since the section of instruction sheets on antisubmarine fire control included quite a bit of information about a typical sonar system. As a result, you are well prepared for the study of "Sonar Fundamentals," which you will undertake before you begin a detailed study of specific antisubmarine fire control equipment.
You already know of the importance of sonar in determining the position of submerged submarines in connection with an antisubmarine attack. You also have a pretty good understanding of how sonar works, what the searchlight and scanning types of search sonar are, what the limitations of sonar are, and how sonar fits into the operation of antisubmarine fire control systems. "Sonar Fundamentals" is intended to supplement and expand your knowledge and understanding of sonar.
Part A-The Story of Sonar, begins with a comparison between radar and sonar and then presents a detailed analysis of how sonar works. The story of submarines and sonar explains the need for and the development of sonar; its various uses are indicated. Part A continues with a description of how targets appear on sonar indicators, and the natural factors and design considerations limiting sonar operation are explained in great detail.
In Part B-The Operation of a Typical Sonar System, the function and operation of the transducer, the driver, receiver, range indicator, bearing and other indicators is described. You will see why scanning type search sonar was developed to overcome the limitations of searchlight type search sonar. You'll get a very detailed and complete analysis of how scanning sonar works. Then you'll read about depth-determining sonar systems.
Part C of "Sonar Fundamentals," which is an introduction to synchro and servos, will not be applicable to your rating, since you will already know about synchros and servos from your study of "Synchro and Servo Fundamentals. "
Parts A and B of "Sonar Fundamentals" will answer any questions about sonar which may have occurred to you when you studied antisubmarine fire control systems in a previous section.
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Conclusion to "Fire Control Fundamentals"
Before you leave "Fire Control Fundamentals" and go on to more advanced studies, let's take a quick look at what you've learned in this section of instruction sheets.
First you saw in "The Story of Fire Control" how guns and early fire control systems were developed. You also made a brief survey of modern fire control systems used for control of main battery, antiaircraft, and other Naval weapons. Then, in "Guns and Interior Ballistics" you learned a little about guns, gun mounts, ammunition and the factors which affect movement of the projectile before it leaves the gun.
In the third section of these sheets-"The Projectile In Flight-Exterior Ballistics"-you performed a careful analysis of the factors which affect a projectile's flight as it travels from gun to target, including such things as air resistance, drift, wind, earth's curvature, etc. The elements of the fire control problem were introduced in "Hitting a Moving Target From a Moving Ship." Here you learned about the effects of own ship and target motion, level and crosslevel and how corrections are made for these factors to solve the fire control problem.
"An Introduction to Fire Control Equipment Operation" explained briefly how the various major units in a typical fire control system operate. In the next two sections-"A Typical Main Battery System" and "Typical Antiaircraft Fire Control Systems"-you took a closer look at fire control systems in action and saw how general principles are applied to specialized systems. From there you went to an analysis of additional specialized systems in the sections which dealt with the antisubmarine, torpedo, and rocket and guided missile fire control problems and the systems used to solve them.
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Conclusion to "Fire Control Fundamentals" (continued)
As you studied each specialized type of fire control problem-main battery, antiaircraft, torpedo and antisubmarine-you saw how they were all simply variations of the same basic problem. You found that in all cases it was necessary to determine the target's present position, predict its future position, stabilize the system, calculate required corrections, and position the weapons to deliver the missile to the target's future position at the proper time. You had a brief look at the various specialized fire control systems designed to solve each problem-you saw what the various components are, what their functions are and how they work together. An important thing to remember, as you recall the many things you've learned from your study of these sheets, is that the various specialized problems are not isolated and distinct, but are closely related to the fundamental fire control problem:
Steps in Solution of the Fire Control Problem
1. Determine present target position in relation to own ship
2. Predict future target position in relation to own ship
3. Stabilize the various units
4. Calculate required corrections to gun elevation and train
5. Transmit data to guns
The target may be above, on or below the ocean's surface. Here are the basic quantities relating own ship and target for surface, air and submerged targets:
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Conclusion to "Fire Control Fundamentals" (continued)
In the preceding section of these sheets you learned about rocket and guided missile fire control. You saw how surface-to-surface rocket control is very much like surface fire of conventional guns. Then you found out about guided missiles, and you saw that they are not as mysterious as you may have thought. The problem of their control is the same as for the control of conventional weapons, except that the former problem is solved after the missile is launched and continues while it is in flight up until the moment of impact with the target; the conventional weapon problem is solved before the weapons are fired.
By studying these sheets you have learned about the common denominator of fire control- the basic fire control problem-and how it applied to the control of any ship's weapons; you have built a solid foundation to which you will soon add the skills and specialized knowledge you will need to qualify as a Fire Control Technician. Now you can begin to talk the FT's language as you have an overall understanding of how the fire control picture fits together. Your job in the future will be to acquire the specialized skills and knowledge that will make you a full-fledged member of a ship's fire control crew. Good luck!!
