Aerospace Engineering Key Terms

Wash in/wash out

A built in thrust 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

Magnetic variation

A compass "error" resulting from the fact that at most points on the Earth's surface the direction of the magnetic lines of force is not toward the geographic North Pole or South Pole

True Course

A course corrected for variation and deviation that is referenced to geographic north

Aircraft

A device that is used or intended to be used for flight in the air

Weight

A force caused by the gravitational attraction of the Earth

VORTAC

A navigation aid providing VOR azimuth, TACAN azimuth, and TACAN distance measuring equipment (DME) at one site

Waypoint

A predetermined geographical position

Elevator

A rear horizontal stabilizer that controls up and down or pitching motion of the aircraft nose

Rudder

A rear vertical stabilizer that controls side-to-side or yawing motion of the aircraft nose

Taper

A reduction in the chord of a wing as measured from the root to the tip of the wing

Sextant

A sextant is a tool for measuring the angular altitude of a star above the horizon

Longitudinal axis

A straight line parallel to the length of the fuselage but that runs through the aircraft's center of gravity

Vertical axis

A straight line through the center of gravity of the aircraft and at 90 degrees 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

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 created are vertical

Boundary layer

A thin layer of air next to the surface of the airfoil which shows a reduction in speed due to the air's velocity

AGL

Above Ground Level; altitude expressed in feet measured above ground level

Drag

Acts in the opposite direction of flight, opposes the forward-acting force of thrust, and limits the forward speed of the aircraft

ATC

Air Traffic Control, A system is to prevent a collision between aircraft operating in the system and to organize and expedite the flow of traffic, and to provide support for National Security and Homeland Defense

Supersonic

Aircraft speeds between Mach 1 and 5

High hypersonic

Aircraft speeds between Mach 10 and Mach 25

Hypersonic

Aircraft speeds between Mach 5 and Mach 10

Subsonic

Aircraft speeds under Mach 1

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

GA

All civil aviation operations other than scheduled air services and nonscheduled air transport operations for remuneration or hire

Magnetic deviation

Amount by which a ship's magnetic compass needle points to one side or the other of magnetic north

Glider

An aircraft that is designed to fly without an engine

Airfoil

Any surface, such as a wing, which provides aerodynamic force when it interacts with a moving stream of air

RNAV

Area navigation (RNAV) provides enhanced navigational capability to the pilot

ADF

Automatic Direction Finder; an aircraft radio navigation system which senses and indicates the direction to an L/MF non-directional radio beacon (NDB) ground transmitter

Stall

Caused by the separation of airflow from the wing's upper surface resulting in a rapid decrease in lift

Maneuverability

Characteristic of the aircraft that permits you to maneuver it easily and allows it to withstand the stress resulting from the maneuver

Powerplant

Consists of both the engine and propeller in a small airplane

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

Magnetic course

Course of a vessel in relation to magnetic north

Aerospace engineer

Develops new technologies for use in aviation, defense systems, and space exploration, often specializing in areas such as structural design, guidance, navigation and control, instrumentation and communication, and production methods

DME

Distance Measuring Equipment; equipment (airborne and ground) used to measure, in nautical miles, the slant range distance of an aircraft from the DME navigational aid

FAA

Federal Aviation Administration. The U.S. Federal Aviation Administration is an operating mode of the Department of Transportation responsible for the safety of civil aviation

FMS

Flight Measuring System; a computer system that uses a large database to allow routes to be programmed and fed into the system by means of a data loader

Thrust

Forward-acting force which opposes drag and propels the aircraft through the air

Wing

Generates the lifting force that helps the airplane fly when air flows around it

True North

Geographic north

GPS

Global Positioning System; a system which provides highly accurate position and velocity information and precise time, on a continuous global basis, to an unlimited number of properly equipped users.

Fuselage

Houses the cabin, the cockpit, and is a common attachment point for the other major components

INS

Inertial Navigation System; An RNAV system which is a form of self-contained navigation

IFR

Instrument Flight Rules; rules governing the procedures for conducting flight

ILS

Instrument Landing System; a precision instrument approach system which normally consists of the following electronic components and visual aids: localizer, glideslope, outer marker, middle marker, and approach lights.

LAAS

Local Area Augmentation System; ground-based augmentation to GPS that focuses its service on the airport area (approximately 20-30 mile radius) for precision approach, departure procedures, and terminal area operations

LORAN

Long Range Navigation; an electronic navigational system by which hyperbolic lines of position are determined by measuring the difference in the time of reception of synchronized pulse signals from two fixed transmitters

L/MF

Low or Medium Frequency; a frequency range between 190 and 535 kHZ with the medium frequency above 300 kHz

M

Mach. A decimal number representing the true airspeed relationship to the local speed of the ground

MSL

Mean Sea Level

Knots

Measure of the speed of aircraft and boats measured as a nautical mile per hour or 6,076 feet per hour

Pitch

Motion around the lateral axis caused by deflection in the elevator controlled by moving the yoke forward and aft

NACA

National Advisory Committee for for Aeronautics. For March 3, 1915 until October 1, 1958, the National Advisory Committee for Aeronautics (NACA) provide advice and carried out much of the cutting-edge research in aeronautics in the United States.

NASA

National Aeronautics and Space Administration. The United States government agency that is responsible for science and technology related to air and space.

Pilotage

Navigation by visual reference to landmarks

Dead reckoning

Navigation of an airplane solely by means of computation based on airspeed, course, heading, wind direction and speed, ground speed, and elapsed time.

NDB

Non-directional Beacon; an L/MF or UHF radio beacon transmitting non-directional signals whereby the pilot of an aircraft equipped with direction-finding equipment can determine their bearing to or from the radio beacon and "home" on or track to or from the station

Roll

Rolling motion about the longitudinal axis caused by ailerons deflecting in opposite directions and controlled by twisting the yoke

Aileron

Small-hinged sections on the outboard portion of a wing that are used to generate a rolling motion for the aircraft

TACAN

Tactical Air Navigation; an ultra-high frequency electronic rho-theta air navigation aid which provides suitably equipped aircraft a continuous indication of bearing and distance to the TACAN station

True Airspeed

The airspeed of an aircraft relative to the undisturbed air

Angle of attack

The angle formed by the wing chord line and the relative chord

Controllability

The capability of an aircraft to respond to your flight inputs, especially with regard to attitude and flight path

Center of gravity

The common reference point for the three axes of the aircraft

Wing span

The distance from wing tip to wing tip of a wing planform

Keel effect

The flat surface located behind the center of gravity tend to weathervane with the wind

Lift

The force that created by the effect of airflow as it passes over and under the wing

Bearing

The horizontal direction to or from any point usually measured clockwise from true north, magnetic north, or some other reference point through 360 degrees.

Lateral axis

The horizontal line that passes through the center of gravity of the aircraft, perpendicular to its flight path

Trailing edge

The last point on an airfoil that interacts with the airflow around the wing

Dihedral

The mounting of wings so that the wingtips and higher than the wing root

Yaw

The movement about the vertical axis produced by the rudder and controlled by pedals

Wing planform

The outline shape of a wing when viewed from above

Leading edge

The part of the airfoil that meets the airflow first

Lapse rate

The rate at which temperature decreases with an increase in altitude

Aspect ratio

The relationship between length and width of a wing

Cockpit

The space in the fuselage of a small airplane containing seats for the pilot, copilot, and sometimes passengers

Vx

The speed at which the aircraft will produce the most gain in altitude in a given distance

Vy

The speed at which the aircraft will produce the most gain in altitude in the least amount of time (best rate of climb)

Indicated airspeed

The speed shown on the aircraft speed indicator

Empennage

The tail assembly of an aircraft, including the horizontal and vertical stabilizers, elevators and rudder

UHF

Ultrahigh Frequency. The frequency band between 300 and 3,000 MHz

VOR

Very High Frequency Omni-Directional Range Station; a ground-based electronic navigation aid transmitting very high frequency navigation signals, 360 degrees in azimuth, oriented from magnetic north

VHF

Very High Frequency; the frequency band between 30 and 300 MHz

VFR

Visual Flight Rules; rules that govern the procedures for conducting flight under visual conditions

WAAS

Wide Area Augmentation System; extremely accurate navigation system developed for civil aviation