Key-Terms 1.2
Aileron
Small-hinged sections on the outboard portion of a wing that are used to generate a rolling motion for an aircraft.
Airfoil
Any surface, such as a wing, which provides aerodynamic force when it interacts with a moving stream of air.
Angle of Attack
The angle formed by the wing chord line and the relative wind.
Aspect Ratio
The relationship between the length and width of a wing.
Boundary Layer
A thin layer of air next to the surface of an airfoil which shows a reduction in speed due to the air’s viscosity.
Center of Gravity
The common reference point for the three axes of the aircraft.
Cockpit
The space in the fuselage of a small airplane containing seats for the pilot, copilot, and sometimes passengers.
Controllability
The capability of an aircraft to respond to your flight inputs, especially with regard to attitude and flight path.
Dihedral
The mounting of wings so that the wingtips and higher than the wingroot.
Drag
Acts in the opposite direction of flight, opposes the forward-acting force of thrust, and limits the forward speed of the aircraft.
Dynamic Stability
Out of its own accord, an aircraft eventually returns to and remains at its equilibrium position over a period of time.
Elevator
A rear horizontal stabilizer that controls up and down or pitching motion of the aircraft nose.
Empennage
The tail assembly of an aircraft, including the horizontal and vertical stabilizers, elevators and rudder.
Flaps
Control surfaces attached to the trailing edge of the wing extending outward from the fuselage to the midpoint of each wing. Flaps can increase the lifting efficiency of the wing and decrease stall speed.
Fuselage
Houses the cabin, the cockpit and is a common attachment point for the other major components.
Glider
An aircraft that is designed to fly without an engine.
Horizontal Stabilizer
A structure that creates up and down forces at the tail to keep the fuselage aligned in pitch with the relative wind. The structure itself is horizontal while the forces it creates are vertical.
High hypersonic
Aircraft speeds between Mach 10 and 25.
Hypersonic
Aircraft speeds between Mach 5 and 10.
Keel Effect
The flat surfaces located behind the center of gravity tend to weathervane with the wind.
Lapse Rate
The rate at which temperature decreases with an increase in altitude.
Lateral Axis
The horizontal line that passes through the center of gravity of the aircraft, perpendicular to its flight path.
Leading Edge
The part of the airfoil that meets the airflow first.
Lift
The force that created by the effect of airflow as it passes over and under the wing.
Longitudinal Axis
A straight line parallel to the length of the fuselage but that runs through the aircraft’s center of gravity.
M
Mach. A decimal number representing the true airspeed relationship to the local speed of sound.
Maneuverability
Characteristic of the aircraft that permits you to maneuver it easily and allows it to withstand the stress resulting from the maneuver.
Pitch
Motion around the lateral axis caused by deflection in the elevator controlled by moving the yoke forward and aft.
Powerplant
Consists of both the engine and propeller in a small airplane.
Stability
Aircraft stability is the characteristic of an airplane in flight that causes it to return to a condition of equilibrium, or steady flight, after it is disturbed.
Stall
Caused by the separation of airflow from the wing’s upper surface resulting in a rapid decrease in lift.
Static Stability
Forces and moments on the body caused by a disturbance tend initially to return the body toward its equilibrium position.
Subsonic
Aircraft speeds under Mach 1.
Supersonic
Aircraft speeds between Mach 1 and 5.
Taper
A reduction in the chord of a wing as measured from the root to the tip of the wing.
Thrust
Forward-acting force which opposes drag and propels the aircraft through the air.
Trailing Edge
The last point on an airfoil that interacts with the airflow around the wing.
Reynolds Number
The ratio of inertial forces to viscous forces.
Roll
Rolling motion about the longitudinal axis caused by ailerons deflecting in opposite directions and controlled by twisting the yoke.
Rudder
A rear vertical stabilizer that controls side-to-side or yawing motion of the aircraft nose.
Vertical Axis
A straight line through the center of gravity of the aircraft and at 90° to lateral and longitudinal axis.
Vertical Stabilizer
A structure that creates left to right forces to keep the fuselage aligned in yaw with the relative wind. The structure itself is vertical while the forces it creates are horizontal.
Wash In/Wash Out
A built in twist in the wing so that the trailing edge at the wingtip is raised (Wash out) or lowered (Wash in). This significantly affects the slow flight and stall characteristics of the wing.
Weight
A force caused by the gravitational attraction of the Earth.
Wing
Generates the lifting force that helps the airplane fly when air flows around it.
Wing Planform
The outline shape of a wing when viewed from above.
Wing Span
The distance from wing tip to wing tip of a wing planform.
Yaw
The movement about the vertical axis produced by the rudder and controlled by pedals.
Small-hinged sections on the outboard portion of a wing that are used to generate a rolling motion for an aircraft.
Airfoil
Any surface, such as a wing, which provides aerodynamic force when it interacts with a moving stream of air.
Angle of Attack
The angle formed by the wing chord line and the relative wind.
Aspect Ratio
The relationship between the length and width of a wing.
Boundary Layer
A thin layer of air next to the surface of an airfoil which shows a reduction in speed due to the air’s viscosity.
Center of Gravity
The common reference point for the three axes of the aircraft.
Cockpit
The space in the fuselage of a small airplane containing seats for the pilot, copilot, and sometimes passengers.
Controllability
The capability of an aircraft to respond to your flight inputs, especially with regard to attitude and flight path.
Dihedral
The mounting of wings so that the wingtips and higher than the wingroot.
Drag
Acts in the opposite direction of flight, opposes the forward-acting force of thrust, and limits the forward speed of the aircraft.
Dynamic Stability
Out of its own accord, an aircraft eventually returns to and remains at its equilibrium position over a period of time.
Elevator
A rear horizontal stabilizer that controls up and down or pitching motion of the aircraft nose.
Empennage
The tail assembly of an aircraft, including the horizontal and vertical stabilizers, elevators and rudder.
Flaps
Control surfaces attached to the trailing edge of the wing extending outward from the fuselage to the midpoint of each wing. Flaps can increase the lifting efficiency of the wing and decrease stall speed.
Fuselage
Houses the cabin, the cockpit and is a common attachment point for the other major components.
Glider
An aircraft that is designed to fly without an engine.
Horizontal Stabilizer
A structure that creates up and down forces at the tail to keep the fuselage aligned in pitch with the relative wind. The structure itself is horizontal while the forces it creates are vertical.
High hypersonic
Aircraft speeds between Mach 10 and 25.
Hypersonic
Aircraft speeds between Mach 5 and 10.
Keel Effect
The flat surfaces located behind the center of gravity tend to weathervane with the wind.
Lapse Rate
The rate at which temperature decreases with an increase in altitude.
Lateral Axis
The horizontal line that passes through the center of gravity of the aircraft, perpendicular to its flight path.
Leading Edge
The part of the airfoil that meets the airflow first.
Lift
The force that created by the effect of airflow as it passes over and under the wing.
Longitudinal Axis
A straight line parallel to the length of the fuselage but that runs through the aircraft’s center of gravity.
M
Mach. A decimal number representing the true airspeed relationship to the local speed of sound.
Maneuverability
Characteristic of the aircraft that permits you to maneuver it easily and allows it to withstand the stress resulting from the maneuver.
Pitch
Motion around the lateral axis caused by deflection in the elevator controlled by moving the yoke forward and aft.
Powerplant
Consists of both the engine and propeller in a small airplane.
Stability
Aircraft stability is the characteristic of an airplane in flight that causes it to return to a condition of equilibrium, or steady flight, after it is disturbed.
Stall
Caused by the separation of airflow from the wing’s upper surface resulting in a rapid decrease in lift.
Static Stability
Forces and moments on the body caused by a disturbance tend initially to return the body toward its equilibrium position.
Subsonic
Aircraft speeds under Mach 1.
Supersonic
Aircraft speeds between Mach 1 and 5.
Taper
A reduction in the chord of a wing as measured from the root to the tip of the wing.
Thrust
Forward-acting force which opposes drag and propels the aircraft through the air.
Trailing Edge
The last point on an airfoil that interacts with the airflow around the wing.
Reynolds Number
The ratio of inertial forces to viscous forces.
Roll
Rolling motion about the longitudinal axis caused by ailerons deflecting in opposite directions and controlled by twisting the yoke.
Rudder
A rear vertical stabilizer that controls side-to-side or yawing motion of the aircraft nose.
Vertical Axis
A straight line through the center of gravity of the aircraft and at 90° to lateral and longitudinal axis.
Vertical Stabilizer
A structure that creates left to right forces to keep the fuselage aligned in yaw with the relative wind. The structure itself is vertical while the forces it creates are horizontal.
Wash In/Wash Out
A built in twist in the wing so that the trailing edge at the wingtip is raised (Wash out) or lowered (Wash in). This significantly affects the slow flight and stall characteristics of the wing.
Weight
A force caused by the gravitational attraction of the Earth.
Wing
Generates the lifting force that helps the airplane fly when air flows around it.
Wing Planform
The outline shape of a wing when viewed from above.
Wing Span
The distance from wing tip to wing tip of a wing planform.
Yaw
The movement about the vertical axis produced by the rudder and controlled by pedals.