Navigation Elements Know the four elements of navigation. Lesson Objective: Know basic engine principles. Samples of Behavior/Main Points Define a list of terms related to basic engine principles. Define Boyle’s Law and Charles’ and Gay-Lussac’s Law. Describe how engines evolved from the earliest version to present day.

Overview Earth’s Size and Shape Position Direction Distance Time Time In this lesson we will discuss: 1. Earth’s Size and Shape 2. Position 3. Direction 4. Distance 5. Time Pt B Direction Pt A

Earth’s Size and Shape For most navigational purposes, the Earth is assumed to be a perfect sphere. Measured at the equator, the Earth is approximately 7,926.41 miles in diameter, and the diameter through the poles is approximately 7,901 miles. Earth’s Size and Shape For most navigational purposes, the Earth is assumed to be a perfect sphere, although, in reality, it is not. Measured at the equator, the Earth is approximately 7,926.41 miles in diameter, and the diameter through the poles is approximately 7,901 miles. The difference of approximately 25 miles does not prevent us from assuming the Earth to be spherical for navigation purposes. This assumption has proved to be practical since, for centuries, navigator’s on the water and in the air have reached their destinations based on it.

Earth’s Size and Shape Great Circles and Small Circles Defined as a circle on the surface of a sphere whose center and radius are those of the sphere itself. It is the largest circle that can be drawn on the sphere. The single most important aspect of great circles for navigators is that the arc, or piece of the circle, is the shortest distance between two points on a sphere. Great Circles and Small Circles Defined as a circle on the surface of a sphere whose center and radius are those of the sphere itself. It is the largest circle that can be drawn on the sphere. The equator and meridians are examples of great circles. The single most important aspect of great circles for navigators is that the arc, or piece of the circle, is the shortest distance between two points on a sphere. Circles on the surface of the sphere other than great circles are defined as small circles. All latitudes, with the exception of the equator are small circles.

Position Lines of reference are necessary in order to locate specific points on the Earth. These lines are known as parallels of latitude and meridians of longitude. The numbers representing a position in terms of latitude and longitude are known as coordinates of that position. Position Lines of reference are necessary in order to locate specific points on the Earth. A system using imaginary reference lines has been developed to locate positions on the Earth. These lines are known as parallels of latitude and meridians of longitude. The numbers representing a position in terms of latitude and longitude are known as coordinates of that position. North Penn N40-14.05, W075-18.58

Position Latitude Parallel with the equator are lines of latitude. Each of these parallel lines is a small circle, and they have a definitive location. The equator is latitude 0o, and the poles are located at 90o latitude. Letter designators N and S are used to show which latitude is meant. Longitude The Greenwich Meridian is sometimes called the prime meridian, although it is actually the zero meridian Longitude is counted east and west from this meridian through 180o The Greenwich Meridian is sometimes called the first or prime meridian, though, actually, it is the zero meridian. Longitude is counted east and west from this meridian through 180o. The Greenwich Meridian is the 0o longitude on one side of the Earth, and, after crossing the poles, it becomes the 180th meridian (180o east or west of the 0o meridian). These designations define the Eastern and Western Hemispheres.

Direction Direction is the position of one point in space, relative to another, without reference to the distance between them. The points of a compass are not adequate for modern navigation. It has been replaced, for the most part, by a numerical system. Direction Direction is the position of one point in space, relative to another, without reference to the distance between them. The points of a compass are not adequate for modern navigation. It has been replaced, for the most part, by a numerical system. The numerical system, divides the horizon into 360°(degrees). Starting with north as 000° and continuing clockwise through east (090°), south (180°), west (270°), and back to north. This circle, called a compass rose, represents the horizon divided into 360°.

Direction Since determination of direction is one of the most important parts of the navigator’s work, the various terms involved should be clearly understood. Course Heading Track Direction Direction is the position of one point in space, relative to another, without reference to the distance between them. The points of a compass are not adequate for modern navigation. It has been replaced, for the most part, by a numerical system.

Direction

Direction A line that makes the same angle with each meridian is called a rhumb line. Flying this sort of path results in a greater distance traveled, but it is easier to steer. Between two points on the Earth, the great circle is shorter than the rhumb line, but the difference is negligible for short distances (except in high latitudes). A line that makes the same angle with each meridian is called a rhumb line. An aircraft holding a constant true heading would be flying a rhumb line. Flying this sort of path results in a greater distance traveled, but it is easier to steer. Between two points on the Earth, the great circle is shorter than the rhumb line, but the difference is negligible for short distances (except in high latitudes). Rhumb Line Great Circle Line

Direction

Distance Measured by the length of a line joining two points. In navigation, the most common unit of measuring distance is the nautical mile. The nautical mile is about 6,076 feet. Statute mile is 5,280 feet Speed: If the measure of distance is nautical miles, it is customary to speak in terms of knots. Distance Measured by the length of a line joining two points. In navigation, the most common unit of measuring distance is the nautical mile. The nautical mile is about 6,076 feet (sometimes rounded to 6,080 feet). Equal to 1 minute of arc on a meridian, which is 1 minute of latitude. To convert nautical miles to statute miles, the nautical mile figure can be multiplied by the factor 1.15. To convert statute miles to nautical miles, multiply the statute miles by 0.87.

Time The Earth makes a complete rotation of 360o during a 24 hour day. Greenwich Mean Time Greenwich Mean Time (GMT) is the time of day at any given moment at Greenwich, England. Zulu Time Time zones are derived as +/- from Zulu Time Zone Time Before the establishment of zone time in 1883, every city and town had its own time. Each time zone is 15o of longitude (1 hour of angular measure) in width, and the first zone centers on the prime meridian. Irregularities have crept into the system. Some towns have decided to keep the time of some large city further east or west. Daylight Saving Time, which sets the clocks one hour ahead in the affected areas. The United States has four standard time zones (in the contiguous states). The time in any given zone is 1 hour earlier than in an adjacent eastern zone and 1 hour later that in an adjacent western zone. Pilots sometimes become confused in reporting their estimated time of arrival (ETA) because they cannot remember whether they must add or subtract an hour.

Phonetic Alphabet and Morse Code

Navigation Elements Know the four elements of navigation. Lesson Objective: Know basic engine principles. Samples of Behavior/Main Points Define a list of terms related to basic engine principles. Define Boyle’s Law and Charles’ and Gay-Lussac’s Law. Describe how engines evolved from the earliest version to present day.