Assisted take-off

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Tow line and towing aircraft seen from the cockpit of a glider Glider in flight.JPG
Tow line and towing aircraft seen from the cockpit of a glider

Assisted takeoff is any system for helping aircraft to get into the air (as opposed to strictly under its own power). The reason it might be needed is due to the aircraft's weight exceeding the normal maximum takeoff weight, insufficient power, insufficient available runway length, or a combination of all three factors. Assisted takeoff is also required for gliders, which do not have an engine and are unable to take off by themselves.

Aircraft machine that is able to fly by gaining support from the air other than the reactions of the air against the earth’s surface

An aircraft is a machine that is able to fly by gaining support from the air. It counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines. Common examples of aircraft include airplanes, helicopters, airships, gliders, and hot air balloons.

Maximum takeoff weight maximum weight of a craft at which takeoff is permitted

The maximum takeoff weight (MTOW) or maximum gross takeoff weight (MGTOW) or maximum takeoff mass (MTOM) of an aircraft is the maximum weight at which the pilot is allowed to attempt to take off, due to structural or other limits. The analogous term for rockets is gross lift-off mass, or GLOW. MTOW is usually specified in units of kilograms or pounds.

Runway Area of surface used by aircraft to takeoff from and land on

According to the International Civil Aviation Organization (ICAO), a runway is a "defined rectangular area on a land aerodrome prepared for the landing and takeoff of aircraft". Runways may be a man-made surface or a natural surface.

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Catapults (CATO)

F/A-18 attached to steam catapult preparatory to launch F18-on catapult.jpg
F/A-18 attached to steam catapult preparatory to launch

A well-known type of assisted takeoff is an aircraft catapult. In modern systems fitted on aircraft carriers, a piston, known as a shuttle, is propelled down a long cylinder under steam pressure. The aircraft is attached to the shuttle using a tow bar or launch bar mounted to the nose landing gear (an older system used a steel cable called a catapult bridle; the forward ramps on older carrier bows were used to catch these cables), and is flung off the deck at about 15 knots above minimum flying speed, achieved by the catapult in a four-second run.

Aircraft catapult device used to launch aircraft from ships

An aircraft catapult is a device used to launch aircraft from ships, most commonly used on aircraft carriers, as a form of assisted take off. It consists of a track built into the flight deck, below which is a large piston or shuttle that is attached through the track to the nose gear of the aircraft, or in some cases a wire rope, called a catapult bridle, is attached to the aircraft and the catapult shuttle. Different means have been used to propel the catapult, such as weight and derrick, gunpowder, flywheel, air pressure, hydraulic, and steam power. The U.S. Navy is developing the use of Electromagnetic Aircraft Launch Systems with the construction of the Gerald R. Ford-class aircraft carriers. Catapulted aircraft land like conventional aircraft, sometimes with the help of arresting gear.

Aircraft carrier Warship that serves as a seagoing airbase

An aircraft carrier is a warship that serves as a seagoing airbase, equipped with a full-length flight deck and facilities for carrying, arming, deploying, and recovering aircraft. Typically, it is the capital ship of a fleet, as it allows a naval force to project air power worldwide without depending on local bases for staging aircraft operations. Carriers have evolved since their inception in the early twentieth century from wooden vessels used to deploy balloons to nuclear-powered warships that carry numerous fighters, strike aircraft, helicopters, and other types of aircraft. While heavier aircraft such as fixed-wing gunships and bombers have been launched from aircraft carriers, it is currently not possible to land them. By its diplomatic and tactical power, its mobility, its autonomy and the variety of its means, the aircraft carrier is often the centerpiece of modern combat fleets. Tactically or even strategically, it replaced the battleship in the role of flagship of a fleet. One of its great advantages is that, by sailing in international waters, it does not interfere with any territorial sovereignty and thus obviates the need for overflight authorizations from third party countries, reduce the times and transit distances of aircraft and therefore significantly increase the time of availability on the combat zone.

The United States is replacing carrier steam catapults with linear induction motors. The system is called the electromagnetic aircraft launch system (EMALS). An electromagnetic wave traveling through the motor propels the armature along its length, pulling the plane with it. With this system, it will be possible to match launch power and aircraft weight more closely than with the steam system, causing less wear on the aircraft.

United States federal republic in North America

The United States of America (USA), commonly known as the United States or America, is a country composed of 50 states, a federal district, five major self-governing territories, and various possessions. At 3.8 million square miles, the United States is the world's third or fourth largest country by total area and is slightly smaller than the entire continent of Europe's 3.9 million square miles. With a population of over 327 million people, the U.S. is the third most populous country. The capital is Washington, D.C., and the largest city by population is New York City. Forty-eight states and the capital's federal district are contiguous in North America between Canada and Mexico. The State of Alaska is in the northwest corner of North America, bordered by Canada to the east and across the Bering Strait from Russia to the west. The State of Hawaii is an archipelago in the mid-Pacific Ocean. The U.S. territories are scattered about the Pacific Ocean and the Caribbean Sea, stretching across nine official time zones. The extremely diverse geography, climate, and wildlife of the United States make it one of the world's 17 megadiverse countries.

Linear induction motor

A linear induction motor (LIM) is an alternating current (AC), asynchronous linear motor that works by the same general principles as other induction motors but is typically designed to directly produce motion in a straight line. Characteristically, linear induction motors have a finite primary or secondary length, which generates end-effects, whereas a conventional induction motor is arranged in an endless loop.

Electromagnetic Aircraft Launch System

The Electromagnetic Aircraft Launch System (EMALS) is a type of aircraft launching system currently under development by General Atomics for the United States Navy. The system launches carrier-based aircraft by means of a catapult employing a linear induction motor rather than the conventional steam piston. EMALS was developed for the Navy's Gerald R. Ford-class aircraft carriers.

JATO and RATO

JATO stands for 'Jet-assisted takeoff' (and the similar RATO for 'Rocket-assisted takeoff'). In the JATO and RATO systems, additional engines are mounted on the airframe which are used only during takeoff. After that the engines are usually jettisoned, or else they just add to the parasitic weight and drag of the aircraft. However, some aircraft such as the Avro Shackleton MR.3 Phase 2, had permanently attached JATO engines. The four J-47 turbojet engines on the B-36 were not considered JATO systems; they were an integral part of the aircraft's powerplants, and were used during takeoff, climb, and cruise at altitude. The Hercules LC-130 can be equipped with a JATO rocket system to shorten takeoff as used in the LC-130 Skibird for polar missions. [1]

Avro Shackleton British long-range maritime patrol aircraft

The Avro Shackleton is a British long-range maritime patrol aircraft (MPA) used by the Royal Air Force (RAF) and the South African Air Force (SAAF). It was developed by Avro from the Avro Lincoln bomber, which itself had been a development of the famous wartime Avro Lancaster bomber.

Lockheed C-130 Hercules Military transport aircraft

The Lockheed C-130 Hercules is an American four-engine turboprop military transport aircraft designed and built originally by Lockheed. Capable of using unprepared runways for takeoffs and landings, the C-130 was originally designed as a troop, medevac, and cargo transport aircraft. The versatile airframe has found uses in a variety of other roles, including as a gunship (AC-130), for airborne assault, search and rescue, scientific research support, weather reconnaissance, aerial refueling, maritime patrol, and aerial firefighting. It is now the main tactical airlifter for many military forces worldwide. More than 40 variants of the Hercules, including a civilian one marketed as the Lockheed L-100, operate in more than 60 nations.

During WW2 the German Arado Ar 234 and the Messerschmitt Me 323 "Gigant" used rocket units beneath the wings for assisted takeoff. Such systems were popular during the 1950s, when heavy bombers started to require two or more miles of runway to take off fully laden. This was exacerbated by the relatively low power available from jet engines at the time—for example the Boeing B-52 Stratofortress required eight turbojet engines to yield the required performance, and still needed RATO for very heavy payloads (a proposed update of the B-52 replaces these with half the number of much more powerful engines). In a Cold War context, RATO and JATO bottles were seen as a way for fighter aircraft to use the undamaged sections of runways of airfields which had been attacked.

Arado Ar 234 airplane

The Arado Ar 234 Blitz was the world's first operational jet-powered bomber, built by the German Arado company in the closing stages of World War II.

Messerschmitt Me 323 German military transport aircraft of World War II

The Messerschmitt Me 323 Gigant ("Giant") was a German military transport aircraft of World War II. It was a powered variant of the Me 321 military glider and was the largest land-based transport aircraft of the war. A total of 213 are recorded as having been made, a few being converted from the Me 321.

Jet engine reaction engine which generates thrust by jet propulsion

A jet engine is a type of reaction engine discharging a fast-moving jet that generates thrust by jet propulsion. This broad definition includes airbreathing jet engines. In general, jet engines are combustion engines.

Gliders

Glider aircraft which do not have an engine also require an assisted takeoff. Apart from self launching gliders, EASA recognizes four other launch methods: winch launches, aerotows, bungee launches and car tows. [2]

Gravity assistance

Early pioneers in powered and unpowered flight used gravity to accelerate their aircraft to a speed which allowed its wings to generate enough lift to achieve independent flight. These included attempts to achieve flight from towers, city walls and cliffs. Generally more successful were attempts in which speed was built up by accelerating down hills and mountain slopes, sometimes on rails or ramps.

Mother ship (carrier) aircraft

An X-15 pictured just after release from a B-52 carrier aircraft X-15 launched bw.jpg
An X-15 pictured just after release from a B-52 carrier aircraft

Probably the ultimate form of gravity assistance is when an aircraft is released from a larger mother ship or mother craft. This may be because the daughter craft is incapable of taking off normally e.g. the atmospheric flight tests of the Space Shuttle.

Usually the rationale for such a system is to free the daughter craft from the need to climb to its release height under its own power. This allows the daughter craft to be designed with fewer weight and aerodynamic restrictions allowing for exotic configurations to be used or tested, for example the recent SpaceShipOne, and previously the Bell X-1 and other X-planes.

In the interwar years, in order to achieve long ranges with the technology of the time, trials were undertaken with floatplanes piggy-backed atop flying boats. With the floatplane carried part of the way to its destination and freed from having to use any of its own fuel in the initial climb, these combinations could deliver light but time-critical cargos faster and farther than a single individual aircraft (for example the Short Mayo Composite).

Hot air balloons have acted as "motherships" to hang gliders and para gliders in altitude and distance record attempts.

See also

Related Research Articles

Fixed-wing aircraft Heavier-than-air aircraft with fixed wings generating aerodynamic lift in the airflow caused by forward airspeed

A fixed-wing aircraft is a flying machine, such as an airplane or aeroplane, which is capable of flight using wings that generate lift caused by the aircraft's forward airspeed and the shape of the wings. Fixed-wing aircraft are distinct from rotary-wing aircraft, and ornithopters. The wings of a fixed-wing aircraft are not necessarily rigid; kites, hang gliders, variable-sweep wing aircraft and aeroplanes that use wing morphing are all examples of fixed-wing aircraft.

JATO type of aircraft assisted take-off

JATO, is a type of assisted take-off for helping overloaded aircraft into the air by providing additional thrust in the form of small rockets. The term JATO is used interchangeably with the term RATO, for rocket-assisted take-off.

Jet aircraft aircraft propelled by jet engines

A jet aircraft is an aircraft propelled by jet engines.

Takeoff transition from being on a surface to being in flight

Takeoff is the phase of flight in which an aerospace vehicle goes from the ground to flying in the air.

Booster (rocketry) typically the first stage of a launch vehicle

A booster rocket is either the first stage of a multistage launch vehicle, or else a shorter-burning rocket used in parallel with longer-burning sustainer rockets to augment the space vehicle's takeoff thrust and payload capability. Boosters are traditionally necessary to launch spacecraft into low Earth orbit, and are especially important for a space vehicle to go beyond Earth orbit. The booster is dropped to fall back to Earth once its fuel is expended, a point known as booster engine cut-off (BECO). The rest of the launch vehicle continues flight with its core or upper-stage engines. The booster may be recovered and reused, as was the case of the Space Shuttle.

Spaceplane vehicle that operates as an aircraft as well as a spacecraft when it is in space

A spaceplane is an aerospace vehicle that operates as an aircraft in Earth's atmosphere, as well as a spacecraft when it is in space. It combines features of an aircraft and a spacecraft, which can be thought of as an aircraft that can endure and maneuver in the vacuum of space or likewise a spacecraft that can fly like an airplane. Typically, it takes the form of a spacecraft equipped with wings, although lifting bodies have been designed and tested as well. The propulsion to reach space may be purely rocket based or may use the assistance of airbreathing jet engines. The spaceflight is then followed by an unpowered glide return to landing.

Nakajima Kikka World War II Japanese twin engined jet aircraft

The Nakajima Kikka was Japan's first jet aircraft. It was developed late in World War II and the first prototype had only flown once before the end of the conflict. It was also called Kōkoku Nigō Heiki.

Rocket-powered aircraft aircraft which uses a rocket engine for propulsion

A rocket-powered aircraft or rocket plane is an aircraft that uses a rocket engine for propulsion, sometimes in addition to airbreathing jet engines. Rocket planes can achieve much higher speeds than similarly sized jet aircraft, but typically for at most a few minutes of powered operation, followed by a glide. Unhindered by the need for oxygen from the atmosphere, they are suitable for very high-altitude flight. They are also capable of delivering much higher acceleration and shorter takeoffs.

Emergency Fighter Program

The Emergency Fighter Program was the program that resulted from a decision taken on July 3, 1944 by the Luftwaffe regarding the German aircraft manufacturing companies during the last year of the Third Reich.

Wunderwaffe term assigned during World War II by the Nazi Germany propaganda ministry to a few revolutionary "superweapons", most of which remained prototypes

Wunderwaffe is German for "Miracle Weapon" and was a term assigned during World War II by the Nazi Germany propaganda ministry to some revolutionary "superweapons". Most of these weapons however remained prototypes, which either never reached the combat theater, or if they did, were too late or in too insignificant numbers to have a military effect.

Airspeed Queen Wasp

The Airspeed AS.30 Queen Wasp was a British pilotless target aircraft built by Airspeed Limited at Portsmouth during the Second World War. Although intended for both Royal Air Force and Royal Navy use, the aircraft never went into series production.

Glider (aircraft) broad type of heavier-than-air aircraft designed for operation without an engine

A glider is a heavier-than-air aircraft that is supported in flight by the dynamic reaction of the air against its lifting surfaces, and whose free flight does not depend on an engine. Most gliders do not have an engine, although motor-gliders have small engines for extending their flight when necessary with some being powerful enough to take off.

Rocket sled launch

A rocket sled launch, also known as ground-based launch assist, catapult launch assist, and sky-ramp launch, is a proposed method for launching space vehicles. With this concept the launch vehicle is supported by an eastward pointing rail or maglev track that goes up the side of a mountain while an externally applied force is used to accelerate the launch vehicle to a given velocity. Using an externally applied force for the initial acceleration reduces the propellant the launch vehicle needs to carry to reach orbit. This allows the launch vehicle to carry a larger payload and reduces the cost of getting to orbit. When the amount of velocity added to the launch vehicle by the ground accelerator becomes great enough, single-stage-to-orbit flight with a reusable launch vehicle becomes possible.

Carrier-based aircraft military aircraft designed specifically for operations from aircraft carriers

Carrier-based aircraft, sometimes known as carrier-capable aircraft or carrier-borne aircraft, are naval aircraft designed for operations from aircraft carriers. They must be able to launch in a short distance and be sturdy enough to withstand the abrupt forces of launching from and recovering on a pitching deck. In addition, their wings are generally able to fold up, easing operations in tight quarters.

Radioplane Q-1 high-speed target drone, U.S. Air Force, 1950

The Radioplane Q-1 was an American target drone, developed in the early 1950s for the United States Air Force by the Radioplane Company. Originally powered by a pulsejet engine, then later developed as an improved turbojet-powered aircraft, the Q-1 failed to win the favor of the USAF. However, the aircraft provided the basis of the GAM-67 Crossbow anti-radar missile.

Powered aircraft aircraft requiring onboard propulsion to maintain flight

A powered aircraft is an aircraft that uses onboard propulsion with mechanical power generated by an aircraft engine of some kind.

Aircraft can have different ways to take off and land. Conventional airplanes accelerate along the ground until sufficient lift is generated for takeoff, and reverse the process to land. Some airplanes can take off at low speed, this being a short takeoff. Some aircraft such as helicopters and Harrier Jump Jets can take off and land vertically. Rockets also usually take off vertically, but some designs can land horizontally.

Conroy Virtus Proposed American large transport aircraft intended to carry the Space Shuttle

The Conroy Virtus was a proposed American large transport aircraft intended to carry the Space Shuttle. Designed, beginning in 1974, by John M. Conroy of the Turbo-Three Corporation, it was to incorporate a pair of Boeing B-52 Stratofortress fuselages to form a new craft using existing parts for cost-savings. While the project was seriously considered, it proved impractically large and NASA chose to develop the Boeing 747-based Shuttle Carrier from surplus commercial aircraft instead.

Ski-jump (aviation) Take-off ramp for aircraft

In aviation, a ski-jump is an upward-curved ramp that allows aircraft to take off from a runway that is shorter than the aircraft's required takeoff roll. By forcing the aircraft upwards, lift-off can be achieved at a lower airspeed than that required for sustained flight, while allowing the aircraft to accelerate to such speed in the air rather than on the runway. Ski-jumps are commonly used to launch airplanes from aircraft carriers that lack catapults.

References

  1. "LC-130 Skibird Aircrews Train for Polar Operations". U.S. DEPARTMENT OF DEFENSE. Retrieved 2018-10-05.
  2. Part FCL Handbook, EASA. EASA (PDF) (1 ed.). European Aviation Safety Agency.