Any system for helping aircraft into the air (as opposed to strictly under its own power), is known as assisted take off. The reason it might be needed is due to the aircraft's weight exceeding the normal maximum take off weight, insufficient power, or the available runway length may be insufficient, or a combination of all three factors. Assisted take off is also required for gliders, which do not have an engine and are unable to take off by themselves. An aircraft is any machine capable of atmospheric flight. ... A runway is a strip of land on an airport, on which aircraft can take off and land. ... Gliders are heavier-than-air aircraft primarily intended for un-powered flight. ...

Catapults

F/A-18 attached to steam catapult preparatory to launch. Note shuttle attached in front of the nose wheel gear and red hold-back bar designed to release at a specified pressure

A well-known type of assisted take off is the 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 mounted to the nose landing gear (an older system used a steel cable; the forward ramps on older carrier bows were used to catch these cables), and is flung off the deck at about 15 knots above mimimum flying speed, achieved by the catapult in a 4 second run. F/A-18 ready for catapult launch from the deck of the USS Abraham Lincoln while in Hawaiian waters. ... F/A-18 ready for catapult launch from the deck of the USS Abraham Lincoln while in Hawaiian waters. ... F/A-18 a split second after the red hold-back bar (on far left) has released and the catapult is hurling the aircract down the deck An aircraft catapult is a device used to launch aircraft from ships — in particular aircraft carriers — as a form of assisted take off. ... An aircraft carrier is a warship whose main role is to deploy and recover aircraft—in effect acting as a sea-going airbase. ...

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 travelling 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. A linear motor is essentially an electric motor that has had its stator unrolled so that instead of producing a torque (rotation), it produces a linear force along its length. ... In electrical engineering, an armature is usually the rotating part of an electric motor or dynamo. ...

The catapult approach is also used for towing gliders into the air. This can be accomplished using an elastic bungee arrangement, or more commonly using a cable wound onto a winch, powered by a large diesel engine. The bungee approach is rarely used for man-carrying gliders, as the acceleration is uncontrolled and can yield very high G-forces. It is commonly used to launch model gliders however. Manned gliders are commonly launched simply by towing them aloft behind a powered aircraft. Bungee may mean: Bungee Jumping, the adventure sport Bungee, the Métis language This is a disambiguation page — a navigational aid which lists pages that might otherwise share the same title. ... A winch is a machine that is used to wind up a rope. ... The diesel engine is a type of internal combustion engine; more specifically, it is a compression ignition engine, in which the fuel is ignited by being suddenly exposed to the high temperature and pressure of a compressed gas containing oxygen (usually atmospheric air), rather than a separate source of ignition... Aircraft modeling or aeromodelling is a hobby that has been popular since the 1930s. ...

JATO and RATO

A system for assisted take off known as JATO for 'Jet-assisted take off' (and the similar RATO, 'Rocket-assisted take off') was popular during the 1950s, when heavy bombers started to require two or more miles of runways to take off fully laden. This was exacerbated by the relatively low powers available from jet engines at the time - for example the B-52 Stratofortress requires 8 turbojet engines to yield the required performance, and still required RATO for very heavy payloads. A proposed update of the B-52 replaces these with half the number of much more powerful engines. In the JATO and RATO system, additional engines are mounted on the airframe which are used only during take off. After that the engines are either jettisoned, or else just add to the parasitic weight and drag of the aircraft. JATO is an acronym for Jet Assisted Take Off. ... // Events and trends The 1950s in Western society was marked with a sharp rise in the economy for the first time in almost 30 years and return to the 1920s-type consumer society built on credit and boom-times, as well as the the baby boom from returning GIs who... A Pratt and Whitney turbofan engine for the F-15 Eagle is tested at Robins Air Force Base, Georgia, USA. The tunnel behind the engine muffles noise and allows exhaust to escape. ... A B-52 in flight The Boeing B-52 Stratofortress is a long-range strategic bomber flown by the United States Air Force since 1952, replacing the Convair B-36 and the Boeing B-47. ... Jet engine diagram Turbojets are the simplest and oldest kind of general purpose jet engine. ...

"Jet Donkeys"

Popular Mechanics cover from 1958 showing "jet donkey" system

An unusual assisted take off scheme was partially developed during the 1950s which consisted of a jet powered truck or dolly which ran either on rubber tyres or rails, used to push a heavy aircraft into the air. Once airborne, the dolly would instantly detach. Because the dolly did not need to fly itself, it was not constrained by the need for low weight, and so could be fitted with very large and powerful engines. The system only reached the early stages of development. The same company was also drawing up plans for a flyable version of the dolly launch system, which it called "jet donkeys". The idea was that a small powerful secondary aircraft could push the heavy main aircraft into the air, detach in flight and return to the airfield to be reused. Sketches of the proposed system show a strange canard-layout aircraft with its cockpit in the tail, pushing the main aircraft via a long extended nose. The system was never developed - presumably common sense and safety considerations prevailed - in any case it was not long before the further development of the jet engine meant that most of these assisted take off schemes became unnecessary. Popular Mechanics magazine - fair use This work is copyrighted. ... Popular Mechanics magazine - fair use This work is copyrighted. ... In aeronautics, canard (French for duck) is a type of fixed-wing aircraft in which the tailplane is ahead of the main lifting surfaces, rather than behind them as in conventional aircraft. ...