Airframe in the context of Reliability engineering

An aerostat (from Ancient Greek ἀήρ (aḗr) 'air' and στατός (statós) 'standing', via French) or lighter-than-air aircraft is an aircraft that relies on buoyancy to maintain flight. Aerostats include unpowered balloons (free-flying or tethered) and powered airships.

The relative density of an aerostat as a whole is lower than that of the surrounding atmospheric air (hence the name "lighter-than-air"). Its main component is one or more gas capsules made of lightweight skins, containing a lifting gas (hot air, or any gas with lower density than air, typically hydrogen or helium) that displaces a large volume of air to generate enough buoyancy to overcome its own weight. Payload (passengers and cargo) can then be carried on attached components such as a basket, a gondola, a cabin or various hardpoints. With airships, which need to be able to fly against wind, the lifting gas capsules are often protected by a more rigid outer envelope or an airframe, with other gasbags such as ballonets to help modulate buoyancy.

The North American Aviation P-51 Mustang is an American long-range, single-seat fighter and fighter-bomber used during World War II and the Korean War, among other conflicts. The Mustang was designed in 1940 by a team headed by James H. Kindelberger of North American Aviation (NAA) in response to a requirement of the British Purchasing Commission. The commission approached NAA to build Curtiss P-40 fighters under license for the Royal Air Force (RAF). Rather than build an old design from another company, NAA proposed the design and production of a more modern fighter. The prototype NA-73X airframe was completed on 9 September 1940, 102 days after contract signing, achieving its first flight on 26 October.

The Mustang was designed to use the Allison V-1710 engine without an export-sensitive turbosupercharger or a multi-stage supercharger, resulting in limited high-altitude performance. The aircraft was first flown operationally by the RAF as a tactical-reconnaissance aircraft and fighter-bomber (Mustang Mk I). In mid 1942, a development project known as the Rolls-Royce Mustang X, replaced the Allison engine with a Rolls-Royce Merlin 65 two-stage inter-cooled supercharged engine. During testing at Rolls-Royce's airfield at Hucknall in England, it was clear the engine dramatically improved the aircraft's performance at altitudes above 15,000 ft (4,600 m) without sacrificing range. Following receipt of the test results and after further flights by USAAF pilots, the results were so positive that North American began work on converting several aircraft developing into the P-51B/C (Mustang Mk III) model, which became the first long-range fighter to be able to compete with the Luftwaffe's fighters. The definitive version, the P-51D, was powered by the Packard V-1650-7, a license-built version of the two-speed, two-stage-supercharged Merlin 66, and was armed with six .50 caliber (12.7 mm) AN/M2 Browning machine guns.

Landing gear is the undercarriage of an aircraft or spacecraft that is used for engaging the surface — typically land, but may also be the surface of a water body — when parking, taxiing, takeoff or landing. It was also formerly called alighting gear by some manufacturers, such as the Glenn L. Martin Company. For aircraft, Stinton makes the terminology distinction undercarriage (British) = landing gear (US).

For aircraft, landing gear is the foundational part of airframe that supports the craft's weight when it is not in flight, keeping the fuselage at a clearance off the ground so it can avoid sustaining frictional/collisional damages. Wheeled landing gear is the most ubiquitous, used in almost all aircraft that perform conventional and short takeoff and landing, while skids or floats are used in aircraft that can take off and land vertically or operate from snow/ice/water. Landing gears from early aircraft are usually fixed, and remain protruded under the aircraft during flight, with no or only partial fairing coverage to reduce drag; while most modern aircraft have retractable undercarriages that fold into the fuselage during flight, which maximizes aerodynamic streamlining and allows for faster airspeeds and smoother flight control.

A carrier-based aircraft (also known as carrier-capable aircraft, carrier-borne aircraft, carrier aircraft or aeronaval aircraft) is a navalised aircraft designed for seaborne flight operations from aircraft carriers. The term is generally applied only to shipborne fixed-wing aircraft that require a runway of some sort for takeoff and landing, as VTOL aircraft such as helicopters are inherently capable of adapting to flight operations from a wide variety of ships (not just aircraft carriers) as long as the served vessel is equipped with helipads or a sufficiently spacious deck that can provide a reliable landing area, which include helicopter carriers, amphibious assault ships, aviation-capable surface combatants (cruisers, destroyers, frigates and some corvettes), container ships and even cruiseliners.

Carrier-based aircraft are designed for many purposes including aerial combat, surface attack, anti-submarine warfare (ASW), search and rescue (SAR), carrier onboard delivery (COD), weather observation, reconnaissance and airborne early warning and control (AEW&C). Such aircraft must be able to take off from the short distance available on the carrier's flight deck and be sturdy enough to withstand the abrupt forces exerted by on a pitching deck due to sea waves. Some modern carrier aircraft are designed for catapult-assisted takeoffs and thus also need to be constructed more robust airframes and landing gears that can handle sudden forward accelerations. Arrestor hook is mandatory feature for those designed for CATOBAR or STOBAR landing, while thrust vectoring or tiltrotor nacelles are commonly seen in those capable of V/STOL operations. In addition, their wings are generally larger (thus can generate more lift) than the land-launched counterparts, and are typically able to fold up or swing back for taxiing, pushback and parking in tight quarters.

An electromagnetic catapult is a type of aircraft catapult that uses a linear induction motor system rather than the single-acting pneumatic cylinder (piston) system in conventional steam catapults. The system is used on aircraft carriers to launch fixed-wing carrier-based aircraft, employing the principles of electromagnetism and Lorentz force to accelerate and assist their takeoff from the shorter flight deck runways. Currently, only the United States and China have successfully developed electromagnetic catapults, which are installed on the Gerald R. Ford-class aircraft carriers (currently only the lead ship CVN-78 being operational), the Type 003 aircraft carrier Fujian and the upcoming Type 076 amphibious assault ship Sichuan (51).

Electromagnetic catapults have several advantages over their older, superheated steam-based counterparts. Electromagnetic operation recharges via electric energy and thus much faster than the pressurization process of steam systems, and does not suffer power loss with distance (where volume expansion within the steam catapult cylinder proportionally reduces pressure), temperature changes (which directly affects pressure according to ideal gas law) and leakages (which matters in pressure vessels but is irrelevant in electromagnet systems). The electromagnetic acceleration is also more uniform (unlike steam acceleration, whose accelerative force is always highest at the very initial phase, thus creating a distinct "jolt"), therefore reducing the stress upon the airframe considerably, resulting in increased safety and endurance as well as lower maintenance costs for the aircraft. Electromagnetic catapults are configurable and can assign varying power outputs to different sections, thus allowing them to tailor optimal acceleration to individual aircraft according to different payload weights and takeoff behaviours. Electromagnetic systems are more compact and also weigh less, have fewer linkage components and thus are expected to cost less and require less maintenance, and also require no fresh water boiling for their operation, thus reducing the need for energy-intensive desalination and sophisticated piping systems used in steam catapults, which take up significantly more space below the flight deck.

The Fairchild Republic A-10 Thunderbolt II, also widely known by the nickname Warthog, is a single-seat, twin-turbofan, straight-wing, subsonic attack aircraft developed by Fairchild Republic for the United States Air Force (USAF). In service since 1977, it is named after the Republic P-47 Thunderbolt strike-fighter of World War II, but is instead commonly referred to as the "Warthog" (sometimes simply "Hog"). The A-10 was designed to provide close air support (CAS) to ground troops by attacking enemy armored vehicles, tanks, and other ground forces; it is the only production-built aircraft designed solely for CAS to have served with the U.S. Air Force. Its secondary mission is to direct other aircraft in attacks on ground targets, a role called forward air controller (FAC)-airborne; aircraft used primarily in this role are designated OA-10.

The A-10 was intended to improve on the performance and firepower of the Douglas A-1 Skyraider. The Thunderbolt II's airframe was designed around the high-power 30 mm GAU-8 Avenger rotary autocannon. The airframe was designed for durability, with measures such as 1,200 pounds (540 kg) of titanium armor to protect the cockpit and aircraft systems, enabling it to absorb damage and continue flying. Its ability to take off and land from relatively short and unpaved runways permits operation from airstrips close to the front lines, and its simple design enables maintenance with minimal facilities.

The de Havilland DH.106 Comet is a four-engine narrow body aircraft developed and manufactured by de Havilland in the United Kingdom. The world's first commercial jet airliner, the Comet 1 prototype first flew in 1949. It features an aerodynamically clean design with four de Havilland Ghost turbojet engines located in the wing roots, a pressurised cabin, and large windows. For the era, it offered a relatively quiet, comfortable passenger cabin and was commercially promising at its debut in 1952.

Within a year of the airliner's entry into service, three Comets were lost in highly publicised accidents after suffering catastrophic mishaps mid-flight. Two of these were found to be caused by structural failure resulting from metal fatigue in the airframe, a phenomenon not fully understood at the time; the other was due to overstressing of the airframe during flight through severe weather. The Comet was withdrawn from service and extensively tested. Design and construction flaws, including dangerous stress concentrations around square cut-outs for the ADF (automatic direction finder) antennas were ultimately identified. As a result, the Comet was extensively redesigned, with structural reinforcements and other changes. Rival manufacturers heeded the lessons learned from the Comet when developing their own aircraft.

The Bell 206 is a family of two-bladed, single- and twin-engined helicopters, manufactured by Bell Helicopter at its Mirabel, Quebec, plant. Originally developed as the Bell YOH-4 for the United States Army's Light Observation Helicopter program, it was not selected by the Army. Bell redesigned the airframe and successfully marketed the aircraft commercially as the five-place Bell 206A JetRanger. The new design was eventually selected by the Army as the OH-58 Kiowa.

Bell also developed a seven-place LongRanger, which was later offered with a twin-engined option as the TwinRanger, while Tridair Helicopters offers a similar conversion of the LongRanger called the Gemini ST. The ICAO-assigned model designation "B06" is used on flight plans for the JetRanger and LongRanger, and the designation "B06T" is used for the twin-engined TwinRangers.

A hardpoint is an attachment location on a structural frame designed to transfer force and carry an external or internal load. The term is usually used to refer to the mounting points (more formally known as a weapon station or station) on the airframe of military aircraft that carry weapons (e.g. gun pods and rocket pods), ordnances (bombs and missiles) and support equipment (e.g. flares and countermeasures, targeting pods or drop tanks), and also include hardpoints (also known as pylons) on the wings or fuselage of a military transport aircraft, commercial airliner or private jet where external turbofan jet engines are often mounted.

Hang gliding is an air sport or recreational activity in which a pilot flies a light, non-motorised, fixed-wing heavier-than-air aircraft called a hang glider. Most modern hang gliders are made of an aluminium alloy or composite frame covered with synthetic sailcloth to form a wing. Typically the pilot is in a harness suspended from the airframe, and controls the aircraft by shifting body weight in opposition to a control frame.

Early hang gliders had a low lift-to-drag ratio, so pilots were restricted to gliding down small hills. By the 1980s this ratio significantly improved, and since then pilots have been able to soar for hours, gain thousands of meters of altitude in thermal updrafts, perform aerobatics, and glide cross-country for hundreds of kilometers. The Federation Aeronautique Internationale and national airspace governing organisations control some regulatory aspects of hang gliding. Obtaining the safety benefits of being instructed is highly recommended and indeed a mandatory requirement in many countries.

The Boeing 747-400 is a large, long-range wide-body airliner produced by Boeing Commercial Airplanes, as an advanced version of the original Boeing 747.The model was first introduced as the Advanced Series 300 was announced at the September 1984 Farnborough Airshow, targeting a 10% cost reduction with more efficient engines and 1,000 nautical miles [nmi] (1,900 km; 1,200 mi). Northwest Airlines became the launch customer with an order for ten aircraft on October 22, 1985. The first 747-400 was rolled out on January 26, 1988, made its maiden flight on April 29, 1988, received type certification on January 9, 1989, and entered service with Northwest a month later on February 9, 1989.

It retains the 747 airframe, including the 747-300 stretched upper deck, with 6-foot (1.8 m) winglets. The 747-400 offers a choice of improved turbofans: the Pratt & Whitney PW4000, General Electric CF6-80C2 or Rolls-Royce RB211-524G/H. Its two-crew glass cockpit dispenses with the need for a flight engineer. It typically accommodates 416 passengers in a three-class layout over a 7,285 nmi (13,492 km; 8,383 mi) range with its 875,000-pound (397 t) maximum takeoff weight (MTOW).

The Airbus A330 is a wide-body airliner developed and produced by Airbus.Airbus began developing larger A300 derivatives in the mid–1970s, giving rise to the A330 twinjet as well as the Airbus A340 quadjet, and launched both designs along with their first orders in June 1987. The A330-300, the first variant, took its maiden flight in November 1992 and entered service with Air Inter in January 1994. The A330-200, a shortened longer-range variant, followed in 1998 with Canada 3000 as the launch operator.

The A330 shares many underpinnings with the airframe of the early A340 variants, most notably the same wing components, and by extension the same structure. However, the A330 has two main landing gear legs instead of three, lower weights, and slightly different fuselage lengths. Both airliners have fly-by-wire controls as well as a similar glass cockpit to increase the commonality. The A330 was Airbus's first airliner to offer a choice of three engines: the General Electric CF6, Pratt & Whitney PW4000, or the Rolls-Royce Trent 700. The A330-300 has a range of 11,750 km (6,340 nmi; 7,300 mi) with 277 passengers, while the shorter A330-200 can cover 13,450 km (7,260 nmi; 8,360 mi) with 247 passengers. Other variants include the A330-200F dedicated freighter, the A330 MRTT military tanker, and the ACJ330 corporate jet. The A330 MRTT was proposed as the EADS/Northrop Grumman KC-45 for the US Air Force's KC-X competition, but lost to the Boeing KC-46 in appeal after an initial win.