Aircraft catapults are used in aviation as a starting aid device when aircraft e can not obtain by our own power, the necessary start-up speed.
This may be the case if, for example, the runway is too short or the driving power of the aircraft is not sufficient for a start. The most common use Search aircraft catapults on aircraft carriers n, because the aircraft could not reach the required speed on the short takeoff distances without support.
The concept of a first, operated by compressed air catapults was born in 1916, and was developed by the German navy chief engineer Wilhelm stone. In the fall of 1918, some experiments were performed with a seaplane W.29, but were not pursued at the end of the First World. Stein received the aircraft manufacturer a job as Director of Operations, where he continued to work on the principle of compressed air-powered catapults ship. There were several models and specially designed aircraft. 1927 HD 15 was first successfully tested with the catapults K-1. It consisted of a start track at which a starting run and the slide was put on the aircraft. To start the slide by means of compressed air and steel cables was accelerated to 100 km / hr and decelerated at the end of the track, where the aircraft broke the catapults. flying boats, and catapults came in the following years, both at war and on civil marine applications (catapults ship e) and were also exported abroad, such as the flying boat HD 55th Until the 1930s into the world’s dominant Catapults.
The development of steam catapults began in the 1930s, as a float plane e and e should be flying boat launched from ships, without letting them beforehand to water. The first was used from 1934 to catapults ships such as Swabia. The steam was supplied from the propulsion system of the ship. Alternatively, one could generate the steam also by a hydrogen peroxide vapor generator.
Later missiles were launched from spinning, such as the Fieseler Fi 103rd Modern aircraft could not take off more conventional (ie without support) decks of aircraft, because the scroll speed and driving profit for the carrier no longer sufficient to reach the minimum airspeed required the increasingly heavy modern aircraft to lift. Therefore, start steam catapults were used there.
The steam catapults in the form known today were developed by the British from captured by the Germans inspinning the Fieseler Fi 103 and 1950 tested on HMS Perseus. Of the took over the U.S. Navy aircraft catapult the new technology and then upgraded other marine n their steam catapults out.
In the bottom of the flight deck’s a rail to be let on a “shuttle” called carriage by means of steam pressure is accelerated. This steam is collected in Carrier nuclear-powered directly from the secondary circuit of the reactor.
At the front of the aircraft, a fold-out connector provides (“tow bar”) for the transmission of power. The plane pulls up to the sled until the tow bar is locked. Then the catapult attracts short, so that a voltage between the aircraft and the sled is no sudden jerk and could cause damage to the nose wheel.
The pressure of the steam is set to catapult the specific weight of the aircraft, so that the required speed can be obtained for the lift at the end of the runway. The advantage of the catapult is reflected in the fact that it allows aircraft to carry larger loads.
Before the start of the aircraft is maintained in its first position via a holding bar (“release bar”) until sufficient steam pressure was built up and the engine E reached the maximum thrust. Then, the holder is released very quickly and the aircraft speed, sufficient to create lift its wings.
The sled is braked at the end of the runway on the shortest route. This is done for a long taper on the front of the carriage, which penetrates into a water-filled tube in the end path of the catapult. Thanks to the conical form and the resulting increase in water displacement takes the braking to quickly and brings the sled to a halt. Then, the carriage for the next start is retracted to its initial position.
Since the beginning of the 21st Century s are also explores electromagnetically driven catapults, because futureto deploy through the use of gas turbines, steam any more and thus the operation would be very expensive. The U.S. Navy upgraded their currently with electromagnetic catapults from (Electromagnetic Aircraft Launch System, EMALS) s using the linear motor s, similar to those of the Transrapid. In this case, the carriage is accelerated by alternating magnetic fields.
Due to the precise mode of action can also be achieved with better starting conditions these systems.
The reliable application of a high electrical power requires a short time, a memory system such as a combination of a flywheel and the generator.