AirframeThe mechanical structure of an aircraft is known as the airframe. This structure is typically considered to include the fuselage, undercarriage, empennage and wings, and excludes the propulsion system. Airframe design is a field of aerospace engineering that combines aerodynamics, materials technology and manufacturing methods with a focus on weight, strength and aerodynamic drag, as well as reliability and cost. Modern airframe history began in the United States when a 1903 wood biplane made by Orville and Wilbur Wright showed the potential of fixed-wing designs.
Yalu RiverThe Yalu River (), known by Koreans as the Amrok River or Amnok River, is a river on the border between China and North Korea. Together with the Tumen River to its east, and a small portion of Paektu Mountain, the Yalu forms the border between China and North Korea. Its valley became the scene of several military conflicts in the past centuries. The Korean name Amnok (압록,鴨綠) is most likely derived from ancient Koreanic language of Goguryeo.
Jet engineA jet engine is a type of reaction engine, discharging a fast-moving jet of heated gas (usually air) that generates thrust by jet propulsion. While this broad definition may include rocket, water jet, and hybrid propulsion, the term typically refers to an internal combustion air-breathing jet engine such as a turbojet, turbofan, ramjet, or pulse jet. In general, jet engines are internal combustion engines.
Air Force OneAir Force One is the official air traffic control designated call sign for a United States Air Force aircraft carrying the president of the United States. In common parlance, the term is used to denote U.S. Air Force aircraft modified and used to transport the president and a metonym for the primary presidential aircraft, VC-25, although it can be used to refer to any Air Force aircraft the president travels on.
Aircraft noise pollutionAircraft noise pollution refers to noise produced by aircraft in flight that has been associated with several negative stress-mediated health effects, from sleep disorders to cardiovascular ones. Governments have enacted extensive controls that apply to aircraft designers, manufacturers, and operators, resulting in improved procedures and cuts in pollution. Sound production is divided into three categories: Mechanical noise—rotation of the engine parts, most noticeable when fan blades reach supersonic speeds.
Area ruleThe Whitcomb area rule, named after NACA engineer Richard Whitcomb and also called the transonic area rule, is a design procedure used to reduce an aircraft's drag at transonic speeds which occur between about Mach 0.75 and 1.2. For supersonic speeds a different procedure called the supersonic area rule, developed by NACA aerodynamicist Robert Jones, is used. Transonic is one of the most important speed ranges for commercial and military fixed-wing aircraft today, with transonic acceleration an important performance requirement for combat aircraft and which is improved by reductions in transonic drag.
PulsejetA pulsejet engine (or pulse jet) is a type of jet engine in which combustion occurs in pulses. A pulsejet engine can be made with few or no moving parts, and is capable of running statically (i.e. it does not need to have air forced into its inlet, typically by forward motion). The best known example may be the Argus As 109-014 used to propel Nazi Germany's V-1 flying bomb. Pulsejet engines are a lightweight form of jet propulsion, but usually have a poor compression ratio, and hence give a low specific impulse.
