VTOL (acronym): "Vertical Take-Off/Landing"
V/STOL (acronym): "Vertical/Short Take-off/Landing" combined capabilities of both VTOL and STOL
undercarriage: aircraft landing gear
FAA: Federal Aviation Administration; U.S. Agency that sets standards for aircraft safety and production requirements and investigates accidents, malfunctions and airlines.
payload: weight of "paying" cargo, including weight of passengers, baggage and other goods.
afterburner: device that increases thrust on jet engines by injecting fuel into the hot exhaust to give a short burst of power.
pressurization: feature that allows planes to fly at high altitude without extra oxygen by maintaining air pressure in the cabin at sea level.
drag chute: parachute used to slow an aircraft down upon landing, decreasing the distance needed to stop.
reverse thrust: engine system that allows for exhaust to be directed forward, or changes the pitch of the propellors so that the thrust can be used to slow down the aircraft and decrease the distance needed to stop.
speed of sound: the speed at which sound travels; this decreases at higher altitudes due to thinner air
Mach: measurement of speed based on the speed of sound being 1; eg: Mach 2 would be twice the speed of sound
subsonic flight: flight at speeds below the speed of sound.
transonic flight: flight at speeds approaching the speed of sound.
supersonic flight: flight at speeds faster than the speed the sound.
supercritical wing: a relatively thick wing that produces less drag than a thinner wing; "A thick wing that thinks it's thin;" high performance in transonic flight and volume to hold extra fuel
turbojet: basic turbine engine design; air is taken in, compressed, mixed with fuel and then ignited, generating thrust; hot exhaust gas is used to drive the first, or primary, compressor
turboprop: turbojet with conventional propeller connected to the turbine being driven by exhaust gases; the propeller is the primary source of thrust; has the advantage of being very light, small and less complex than a piston engine of similar power
turbofan/ducted fan: similar to turbojet & turbo prop; large fan contained in an enclosed duct creates most of the thrust and is driven by a turbine turned by exhaust gases; very quiet compared to turbojet, used on most modern commercial jets
"mark": a version; eg: "the Mark 1" the first of a series of variations on one aircraft; "the Mark 6" would be the 6th variation
specs: specifications; performance figures of an aircraft, including dimensions, weight, payload, speed and cost.
stall: a condition in which the airflow over a wing breaks away and ceases to produce lift; a stalled wing is no longer flying
stall speed: the speed at which a wing stalls;
flaps: devices used to increase wing surface area reducing stall speed; a reduced stall speed permits landing and taking off at lower speeds thereby reducing take-off and landing distances; STOL aircraft generally have greater flap area than non-STOL aircraft
spoilers: devices used to destroy the lifting qualities of a wing; in aircraft such as gliders that have very efficient wings, spoilers are needed to allow the aircraft to descend; ground spoilers are used to destroy lifting capability once on the ground which allows for more positive control and braking action
spin: a stall with rotation added