# An Introduction to Aerodynamics

## CONTENTS OF CURRICULUM UNIT 88.06.07

- Table of Content
- 1. Rationale for the Unit
- 1. General Objectives
- 3. Content and Specific Objectives for the Unit
- Navigation and Spherical Geometry
- The Earth’s Surface and Mapping
- 4. Symbols, Diagrams and Definitions Used
- 5. Sample Items Illustrating Some Of The Specific Objectives
- 6. Sample Lesson Plans: #1
- Lesson plan #2
- Lesson plan #3
- References

### Unit Guide

## Aerodynamics: The Mathematical Implications

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## The Earth’s Surface and Mapping

If the string is extended around the globe then the circle is divided into two halves, the line is called the great circle: The shortest distance between any two points will be a portion of the great circle.

Locating a point on the earth’s surface.

To form a system of reference, meridians running in straight lines are draw from the pole meridian drawn in degrees from east to west of Greenich (England). The prime meridian is called longitude zero.

Lines of latitude are drawn at 90 Degree angles to the meridians starting at the equator, these lines are called latitude lines.

To locate a point the coordinates of the point is given usually latitude followed by the longitude.

How a pilot plans a trip.

(a) draw a straight line between the two points (b) measure the course in degrees from true north from a point about midway on the course. This is called True Course (T.C). The effect of winds. When an airplane moves through the air mass at a given airspeed, the airspeed remains constant, but the aircraft’s speed measured by the distance it travels over ground is affected by the movement of the air.

*(figure available in print form)*

A course is the direction towards it’s destination. If there is no wind the aircraft will fly towards it’s direction. If the wind is blowing it will affect the aircraft’s tract. In order to establish a heading direction in which the plane is going a parallelogram of forces is constructed.

*(figure available in print form)*

problem. | T.C = A to ,90 degrees |

Distance A to = 150 miles | |

Wind Velocity = 35 knots (40 m.p.h.) | |

Airspeed = 120 m.p.h | |

Variation = 7 degrees East. |

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Constructing a wind triangle.
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- 1) draw a north-south line, locate T.C at the 90 degree point, and the direction from which the air is blowing at 45 degree point.

*(figure available in print form)*

- 2) Draw the wind vector in the direction of its force.

*(figure available in print form)*

Completed Diagram.

- 3) Using the same scale draw a line from the end of the wind arrow.
- 4.) The true heading () can be measured directly with the protractor.
- 5) The wind correction angle can also be measured with a protractor
- 6) ground speed can be measured along T.C. Iines from point E to the vector at point P.

*(figure available in print form)*

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Calculating Time of a Trip and Fuel Consumption.
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After the pilot has determined his path, he needs to calculate the time and fuel required for the trip. He needs to have fuel for the trip and enough reserve for 45 minutes of extra flying time.

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Calculations Required.
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Calculating minutes to hours.

To find the time in flight when groundspeed is known

Time = distance/groundspeed.

To find the distance flown for a given time

groundspeed x time = distance.

The groundspeed in flight is often not the same as calculated, this variation is due to wind velocity. To calculate groundspeed accurately use

groundspeed = distance between check points/time.

To calculate fuel consumption:

Fuel = fuel consumed/time.