Fundamentals of Flight

Question 1

What is Motion?

Answer 1

Motion is the act, or process, of changing place or position; simply put, motion is movement. Motion is the basic fundamental of aviation.

Question 2

Define Acceleration:

Answer 2

The rate of change of the speed and or velocity of matter with time.

Question 3

Define Speed:

Answer 3

The rate of movement in terms of distance measured in an allotted amount of time.

Question 4

Define Velocity:

Answer 4

The quickness or speed of an object in a given time and direction.

Question 5

Define Force:

Answer 5

Something that causes a change in the motion of an object.

Question 6

Define Inertia:

Answer 6

The willingness of an object to remain at rest or to continue is motion unless acted upon by an outside force.

Question 7

3 Types of motion:

Answer 7

• Linear Motion is when all of a body moves in a line (straight or curved) with all parts moving in the same direction.
• Angular Motion is when a body or part of it moves in a circle (or part of) about a point called the axis of rotation.
• General Motion is a combination of linear and angular motion.

Question 8

Newton’s First Law:

Answer 8

According to Newton’s first law of motion (inertia), an object at rest will remain at rest, or an object in motion will continue in motion at the same speed and in the same direction, until acted upon by an outside force.

Question 9

Newton’s Second Law:

Answer 9

The second law of motion (force) states that if an object moving with uniform speed is acted upon by an external force, the change of motion, or acceleration, will be directly proportional to the amount of force and inversely proportional to the mass of the object being moved.

Question 10

Newton’s Third Law:

Answer 10

The third law of motion (action and reaction) states that for every action there is an equal and opposite reaction.

Question 11

Bernoulli’s principle:

Answer 11

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 ability 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 of the air 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, 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.

Question 12

Define Lift:

Answer 12

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.

Question 13

Define Weight:

Answer 13

The force of gravity acting downward on the aircraft and everything on the aircraft.

Question 14

Define Drag:

Answer 14

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.

Question 15

Define Thrust:

Answer 15

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.

Question 16

3 Axis of Aircraft:

Answer 16

• Longitudinal axis. An imaginary reference line running down the center of the aircraft between the nose and tail.
• Lateral axis. An imaginary reference line running parallel to the wings.
• Vertical axis. An imaginary reference line running from the top to the bottom of the aircraft.

Question 17

Rotary Wing Aircraft Axis are manipulated by what?

Answer 17

• The cyclic stick (roll/pitch). Tilts the plane (angle) of the rotor blades forward, aft or sideways, giving the helicopter its directional motion by changing the direction of the lift; from vertical to a varying degree based on a 0° centerline.
• Tail rotor (yaw). This component counteracts torque of the main rotor by increasing or decreasing the amount of horizontal thrust the tail rotor produces, this movement is around the vertical axis.

Question 18

Purpose of Flaps (leading/trailing edge):

Answer 18

Creates extra lift by lengthening the top section of the wing resulting in maximum lift to reduce takeoff runs and landing rollout.

Question 19

Purpose of Spoilers:

Answer 19

Used to decrease or spoil wing lift by destroying the smooth flow of air over the wing surfaces, this creates a more predictable landing glideslope.

Question 20

Purpose of Speed brakes:

Answer 20

Hinged or moveable control surfaces used for reducing the speed of aircraft. Location varies on the model of aircraft; however the purpose remains the same.

Question 21

Purpose of Slats:

Answer 21

Slats are movable control surfaces attached to 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.

Question 22

Define Autorotation:

Answer 22

A method of allowing a helicopter to land safely from altitude without using engine power. As a helicopter is descending in altitude the collective is lowered allowing the reverse airflow through the rotor to maintain RPM. When the helicopter reaches a predetermined altitude the collective pitch is increased to convert inertial energy into lift to reduce the rate of descent and cushion the landing.

Question 23

Describe the Basic aircraft hydraulic system:

Answer 23

• A reservoir to hold a supply of hydraulic fluid.
• A pump to provide a flow of fluid.
• Tubing to transmit the fluid.
• A selector valve to direct the flow of fluid.
• An actuating unit to convert the fluid pressure into useful work.

Question 24

Landing gear main components and their purpose:

Answer 24

• Shock Strut Assembly. Absorbs the shock that otherwise would be sustained by the airframe.
• Tires. Allows the aircraft to roll easily and provides traction during takeoff and landing.
• Wheel Brake Assembly. Used to slow and stop the aircraft. Also used to prevent the aircraft from rolling while parked.
• Retracting and Extending Mechanism. All the necessary hardware to electrically or hydraulically extend and retract the landing gear.
• Side Struts and Supports. Provides lateral strength/support for the landing gear.

Question 25

Describe Turbojet Engines:

Answer 25

Projects a column of air to the rear at an extremely high velocity. The resulting effect is to propel the aircraft in the opposite or forward direction.

Question 26

Describe Turboshaft:

Answer 26

Delivers power through a shaft to drive something other than a propeller. The power take off may be coupled directly to the engine, but in most cases it is driven by its own free turbine located in the exhaust stream that operates independently on the engine. They have a high power-to-weight ratio and are currently used in helicopters.

Question 27

Turboprop:

Answer 27

Propulsion is accomplished by the conversion of the majority of the gas-energy into mechanical power to drive a propeller. This is done by the addition of more turbine stages. Only a small amount of jet thrust is obtained on a turbo prop engine.

Question 28

Turbofan:

Answer 28

Basically the same as a turbo prop except that the propeller is replaced by a duct-enclosed axial-flow fan. The fan can be part of the first stage compressor or mounted as a separate set of fan blades driven by an independent turbine depending on the fan design, it will produce somewhere around 50 percent of the engine’s total thrust.

Question 29

Fuel Types:

Answer 29

• JP8-NATO Code F-34
  Has a flame spread rate of 100 feet per minute, and a flashpoint of 100 degrees F or 40 degrees C.
• JP4-NATO Code F-40
  Has a flame spread rate of 700-800 feet per minute and a low flashpoint of -10 degrees F or -23 degrees C. Never used on ships. Use of JP4 will normally cause an engine to operate with a lower exhaust gas temperature (EGT), slower acceleration, and lower engine RPM.
• JP5-NATO Code F-44
  Has a flame spread rate of 100 feet per minute, and a flashpoint of 140 degrees F or 60 degrees C. JP-5 is the only approved fuel for use aboard naval vessels. The lowest flashpoint considered safe for use aboard naval vessels is 140 degrees F. This is the Navy’s primary jet fuel.