105. Aviation Fundamentals Page 1 of 43
105. AVIATION FUNDAMENTALS
References:
[a] NAVAIR 00-80T-80, Aerodynamics for Naval Aviators
[b] NAVEDTRA 14014, Airman
[c] NAVAIR 00-80T-88, Helicopter History and Aerodynamics Manual
[d] NAVEDTRA 12300, Aviation Machinist’s Mate 3&2
[e] NAVEDTRA 14176, NEETS Module 4--Introduction to Electrical Conductors, WiringTechniques, and Schematic Reading
[f] NAVEDTRA 14313, Aviation Ordnanceman
[g] NAVEDTRA 14175, NEETS Module 3--Introduction to Circuit Protection, Control, andMeasurement
[h] NAVEDTRA 14188, NEETS Module 16--Introduction to Test Equipment
[i] NAVEDTRA 14028, Aviation Electronics Technician 3
[j] NAVEDTRA 14192, NEETS Module 20--Master Glossary and Index
[k]
[l] NAVAIR 00-80T-105, CV NATOPS Manual
[m] NAVAIR 00-80T-96, Common Support Equipment Basic Handling and Safety Manual
[n] NAVAIR 00-80T-106, LHA/LHD/MCS NATOPS Manual
[o] NAVAIR 00-80T-120, CV Flight/Hangar Deck NATOPS Manual
[p] OPNAVINST 5100.19D, Navy Occupational Safety and Health (NAVOSH) ProgramManual for Forces Afloat
[q] Local Directives and Standard Operating Procedures
[r] NAVAIR 00-80T-113, Aircraft Signals NATOPS Manual
[s] NAVAIR 00-80R-14, NATOPS U.S. Navy Aircraft Firefighting and Rescue Manual
[t] NAVEDTRA 14353, Aviation Boatswains Mate (H)
[u] NAVAIR 19-25-514, Firefighting Vehicle A/S32P-25
[v] NAVEDTRA 14208, Photography (Advanced)
[w] NAVEDTRA 14127, Intelligence Specialist 3&2, Vol. 1
[x] NAVAIR 01-Fl4AAA-1, F-14 NATOPS
[y] NAVEDTRA 14312, Aerographer's Mate Module 5 - Basic Meteorology
[z] NAVEDTRA 14269, Aerographer’s Mate Module 1 - Surface Weather Observations
[aa] NAVEDTRA 14010, Aerographer’s Mate 1&C
[ab] OPNAVINST 3120.32C, Standard Organization and Regulations Manual of the U.S.Navy (SORM)
1 Explain the following expressions of motion: [ref. a]
a. Potential energy:(Stored Energy) The energy stored in a body or system; the energy that a body or system has stored because of its position in an electric, magnetic, or gravitational field, or because of its configuration.
b. Kinetic energy: (Energy in Motion)Thekinetic energy of an object is the extra energy which it possesses due to its motion. It is defined as the work needed to accelerate a body of a given mass from rest to its current velocity. Having gained this energy during its acceleration, the body maintains this kinetic energy unless its speed changes.
.2 Describe the following terms pertaining to motion: [ref. b, ch. 3]
a. Inertia: The tendency of a body at rest to remain atrest, and a body in motion to continue to move at aconstant speed along a straight line, unless the bodyis acted upon in either case by an unbalanced force.
b. Acceleration: A change in the velocity of abody, or the rate of such change with respect tospeed or direction.
c. Speed: The rate of movement or motion in a given amount of time. Speed is the term used when only the rate of movement is meant. If the rate of movement of a ship is 14 knots, we say its speed is 14 knots per hour.
d. Velocity: The quickness or speed of an object in a given time and direction. For example: 200 mph due north.
.3 Define Bernoulli's principle. [ref. b, ch. 3]
* The principle states that when a fluid flowing through a tube reaches a constriction or narrowing of the tube, the speed of the fluid passing through the constriction is increased and its pressure decreased. The general lift of an airfoil is dependent upon the airfoil's being able to create circulation in the air stream and develop the lifting pressure over the airfoil surface. As the relative wind strikes the leading edge of the airfoil, the flow of air is split. Part is deflected upward and aft, and the rest is deflected down and aft. Since the upper surface of the wing has camber or a curve on it, the flow over its surface is disrupted, and this causes a wavelike effect to the wing. The lower surface is relatively flat. Lift is accomplished by the difference in the airflow across the airfoil.
.4 Define Boyle’s law. [ref. b, ch. 3]
* States that when the temperature is held constant, the volume of a gas is inversely proportional to its pressure. Therefore, if the pressure increases, the volume decreases and visa versa. For example, if the volume if halved, then the pressure is doubled. If the temperature is held constant, it becomes an isothermal process. Discovered by Robert Boyle (1627-1691), an Irish physicist and chemist and co-founder of the Royal Society
.5 Describe the following properties of the atmosphere as it relates to aircraftperformance: [ref. a]
a. Static pressure: The static pressure of the airat any altitude results from the mass of airsupported above that level. At standard sealevel conditions the static pressure of the airis 2,116 psf (or 14.7 psi, 29.92 in. Hg, etc.)and at 40,000 feet altitude this static pressuredecreases to approximately 19 percent of the sea level value.
b. Absolute temperature: The ordinary temperature measurement by the
Centigrade scale has a/datum at the freezingpoint of water but absolute zero temperatureis obtained at a temperature of -273“ Centigrade.Thus, the standard sea level temperatureof 15” C. is an absolute temperature of288”. This scale of absolute temperature usingthe Centigrade increments is the Kelvin scale,e.g., o K.
c. Density: The density of the air is a propertyof greatest importance in the study ofaerodynamics. The density of air is simplythe mass of air percubic foot of volume andis a direct measure of the quantity of matterin each cubic foot of air. Air at standard sea level conditions weighs 0.0765 pounds per cubicfoot and has a density of 0.002378 slugs percubic foot. At an altitude of 40,000 feet theair density is approximately 25 percent of thesea level value.
d. Viscosity: The viscosity of the air isimportant in scale and friction effects. Thecoefficient of absolute viscosity is the proportionbetween the shearing stress and velocitygradient for a fluid flow. The viscosity ofgases is unusual in that the viscosity is generallya function of temperature alone and anincrease in temperature increases the viscosity.
e. Standard atmosphere: The standardatmosphere actually represents the mean oraverage properties of the atmosphere. Notice that the lapserate is constant in the troposphere and thestratosphere begins with the isothermal region.Since all aircraft performance is comparedandevaluated in the environment of the standardatmosphere, all of the aircraft instrumentationis calibrated for the standard atmosphere.
f. Pressure altitude: Pressure altitude is the altitude in the standard atmospherecorresponding to a particular pressure. Theaircraft altimeter is essentially a sensitivebarometer calibrated to indicate altitude inthe standard atmosphere. If the altimeter isset for 29.92 in. Hg the altitude indicated isthe pressure altitude-the altitude in the standardatmosphere corresponding to the sensedpressure. Of course, this indicated pressurealtitude may not be the actual height abovesea level due to variations in temperature,lapse rate; atmospheric pressure, and possibleerrors in the sensed pressure.
g. Density altitude: The more appropriate term for correlatingaerodynamic performance in the nonstandardatmosphere is density altitude inthe standard atmosphere corresponding to aparticular value of air density. The computationof density altitude must certainly involveconsideration of pressure (pressure altitude)and temperature.
.6 Describe the following aerodynamic terms and their interrelationships: [ref. b, ch. 3]
a. Lift: The force that acts, in an upward direction, to support the aircraft in the air. It counteracts the effects of weight. Lift must be greater than or equal to weight if flight is to be sustained.
b. Weight: The force of gravity acting downward on the aircraft and everything on the aircraft
c. Drag: The force that tends to hold an aircraft back. Drag is caused by the disruption of the air about the wings, fuselage or body, and all protruding objects on the aircraft. Drag resists motion.
d. Thrust: The force developed by the aircraft's engine, and it acts in the forward direction. Thrust must be greater than or equal to the effects of drag in order for flight to begin or be sustained
e. Longitudinal axis: An imaginary reference line running down the center of the aircraft between the nose and tail. The axis about which roll occurs.
f. Vertical axis: An imaginary reference line running parallel to the wings and about which pitch occurs
g. Lateral axis: An imaginary reference line running from the top to the bottom of the aircraft. The movement associated with this axis is yaw.
h. Angle of attack: The angle at which a body, such as an airfoil or fuselage, meets a flow of air. Defined as the angle between the chord line of the wing (an imaginary straight line from the leading edge to the trailing edge of the wing) and the relative wind. The relative wind is the direction of the air stream in relationship to the wing. For example, an aircraft in straight and level flight has the relative wind directly in front of it and has zero angle of attack since the relative wind is directly striking the leading edge of the wing. An aircraft flying parallel to the ground which has the nose trimmed significantly up, now has the leading edge of the wing (chord line) pointed at an upward angle; however, the relative wind is striking the bottom of the wing. An analogy is to hold your hand out of the car window with your palm facing the ground (zero angle of attack), and then to rotate your hand slightly in either direction. Angle of attack is measured in "units" as opposed to degrees.
.7 State the three primary movements of aircraft about the axis. [ref. b, ch. 3]
a. Pitch - The movement of the aircraft about its lateral axis. The up and down motion of the nose of the aircraft.
b. Yaw - The movement of the aircraft about its vertical axis. The drift, or right or left movement of the nose of the aircraft.
c. Roll - The movement of the aircraft about its longitudinal axis. The movement of the wing tips one up and the other down.
.8 State the purpose of the following flight control surfaces: [ref. b, ch. 4]
a. Flap:Gives the aircraft extra lift. The purpose is to reduce the landing speed, thereby shortening the length of the landing rollout. They also facilitate landing in small or obstructed areas by permitting the gliding angle to be increased without greatly increasing the approach. The use of flaps during takeoff serves to reduce the length of the takeoff run. Some flaps are hinged to the lower trailing edges of the wings inboard of the ailerons. Leading edge flaps are in use on the Navy F-4, Phantom II.
b. Spoiler: Used to decrease wing lift. However, the specific design, function, and use vary with different aircraft. On some aircraft, the spoilers are long narrow surfaces, hinged at their leading edge to the upper surfaces of the wings. In the retracted position, they are flush with the wing skin. In the raised position, they greatly reduce wing lift by destroying the smooth flow of air over the wing surfaces
c. Speed brakes:Hinged or moveable control surfaces used for reducing the speed of aircraft. On some aircraft, they are hinged to the sides or bottom of the fuselage; on others they are attached to the wings. They keep the speed from building too high in dives. They are also used to slow the speed of the aircraft prior to landing.
d. Slats: Slats are movable control surfaces attached to the leading edge of the wing. When the slat is retracted, it forms the leading edge of the wing. When open, or extended forward, a slot is created between the slat and the wing leading edge. High-energy air is introduced into the boundary layer over the top of the wing. At low airspeeds, this improves the lateral control handling characteristics, allowing the aircraft to be controlled at airspeeds below the normal landing speed. This is known as boundary layer control. Boundary layer control is intended primarily for use during operations from carriers; that is, for catapult takeoffs and arrested landings
e. Horizontal stabilizer:Provides stability of the aircraft about its lateral axis. This is longitudinal stability. It serves as the base to which the elevators are attached. On some high-performance aircraft, the entire vertical and/or horizontal stabilizer is a movable airfoil. Without the movable airfoil, the flight control surfaces would lose their effectiveness at extremely high speeds.
f. Vertical stabilizer: Maintains the stability of the aircraft about its vertical axis. This is known as directional stability. The vertical stabilizer usually serves as the base to which the rudder is attached.
g. Rudder: The rudder is attached to the vertical stabilizer. Itdetermines the horizontal flight (turning or yawingmotion) of the aircraft. This action is known asdirectional control.
h. Main rotor blades: The main rotor of a helicopter consists of two ormore rotor blades. Lift is accomplished by rotating theblades through the air at a high rate of speed. Lift maybe changed by increasing the angle of attack or pitch ofthe rotor blades. When the rotor is turning and theblades are at zero angle (flat pitch), no lift is developed.This feature provides the pilot with complete control ofthe lift developed by the rotor blades.The rotor head is fully articulating and is rotated bytorque from the engines through the drive train andmain gearbox or transmission. The flight controls andhydraulic servos transmit movements to the rotorblades.
i. Tail rotor blades:Mounted vertically on the outer portion of the helicopter's tail section. The tail rotor counteracts the torque action of the main rotor by producing thrust in the opposite direction. The tail rotor also controls the yawing action of the helicopter.
j. Aileron: The ailerons and elevators are operated from thecockpit by a control stick on single-engine aircraft. Ayoke and wheel assembly operates the ailerons andelevators on multiengine aircraft, such as transport andpatrol aircraft. The rudder is operated by foot pedals onall types of aircraft.
k. Elevator: The elevators are attached to the horizontalstabilizer and control the climb or descent (pitchingmotion) of the aircraft. This action is known as lateralcontrol.
.9 Identify and state the purpose of the primary flight controls for: [ref. b, ch. 4]
a. Fixed wing aircraft: The ailerons provide control about the longitudinal axis, the elevators provide control about the lateral axis, and the rudder provides control about the vertical axis.
b. Rotary wing aircraft:The collective stick controls the pitch of the rotor blades, which translates to "up and down". The cyclic stick tilts the plane of the rotor blades forward, aft or sideways, giving the helicopter its directional motion. Lateral control is provided using the foot pedals to control the blades on the tail rotor.
.10 State the purpose of the following: [ref. b, ch. 7]
a. Pitot-static: The pitot-static system in an aircraft includes some of the instruments that operate on the principle of the barometer. It consists of a Pitot-static tube and 3 indicators, all connected with tubing that carries air. The three indicators are the altimeter, airspeed indicator, and the rate-of-climb indicator. Each operates on air taken from outside the aircraft during flight. The tube or line from the Pitot tube to the airspeed indicator applies the pressure of the outside air to the indicator. The indicator is calibrated so various air pressures cause different readings. The Pitot tube is mounted on the outside of the aircraft at a point where air is least likely to be turbulent. It points in a forward direction parallel to the aircraft's line of flight. Static means stationary or not changing. The static port introduces outside air, at its normal outside atmospheric pressure, as though the aircraft were standing still in the air. The static line applies this outside air to the airspeed indicator, altimeter, and rate-of-climb indicator.
b. Airspeed indicator: The airspeed indicator displays the speed of the aircraft in relation to the air in which it is flying. In some instances, the speed of the aircraft is shown in Mach numbers. The Mach number gives the speed compared to the speed of sound in the surrounding medium (local speed). For example, if an aircraft is flying at a speed equal to one-half the local speed of sound, it is flying at Mach 0.5. If it moves at twice the speed of sound, its speed is Mach 2.
c. Altimeters:The altimeter shows the height of the aircraft above sea level. The face of the instrument is calibrated so the counter or pointer displays the correct altitude of the aircraft.
d. Rate-of-climb:The rate-of-climb indicator shows the rate at which an aircraft is climbing or descending
e. Attitude indicator:A pilot determines aircraft attitude by referring to the horizon. Often, the horizon is not visible. When it is dark, overcast, smokey, or dusty, the earth's horizon may not be visible. When one or more of these conditions exists, the pilot refers to the attitude indicator. It is also called the vertical gyro indicator or VGI. The instrument shows the pilot the relative position of the aircraft compared to the earth's horizon.
f. Turn and bank indicator: Shows the correct execution of a turn and bank. It also shows the lateral attitude of the aircraft in straight flight. It consists of a turn indicator and a bank indicator. The turn indicator is a gyro mounted in a frame that is pivoted to turn on a longitudinal axis. The direction of the turn is shown on the dial by a pointer. The gyro consists of a glass ball that moves in a curved glass tube filled with a liquid. When the pilot is executing a properly banked turn, the ball stays in the center position. If the ball moves from the center, it shows the aircraft is slipping to the inside or outside of the turn.
g. Navigation systems:Navigation systems and instruments direct, plot, and control the course or position of the aircraft. These may include the radios, transmitters, TACAN, LORAN, etc.
j. Magnetic (standby) compass: A direct-reading magnetic compass ismounted on the instrument panel. The face of thecompass is read like the dial of a gauge