Electromagnetic aircraft launch system
The first trial take-off of an aircraft took place from the deck of a US Navy cruiser USS Birmingham in 1910 and the first trial landing took place in 1911. The first plane to take-off from a ship under way was from the deck of Royal Navy’s HMS Hibernia in 1912. The Japanese were meanwhile trying another approach by carrying sea planes on Seaplane tender support ships during World War I. During September 1914, the Imperial Japanese Navy Ship Wakamiya conducted the world’s first naval-launched air raid against the Germans. Wakamiya carried four Maurice Farman seaplanes, which took–off and landed on the water and were lowered from and raised to the deck by crane. The development of flat top vessels produced the first large fleet ships. In 1918, Royal Navy’s HMS Argus became the world’s first ship capable of launching and landing naval aircraft.
Since then the technique for the take-off and landing aircraft from an aircraft carrier has become more refined and safe. The common systems in vogue are: • CAtApuLt-AssIstED tAKE-oFF But ArrEstED-rECovEry (CAtoBAr). Catobar system is used for heavier aircraft carrying extensive payload. US, France and Brazil use this system. The catapult is a device used for launching an aircraft from aircraft carriers and follows the same principal of a catapult with which one played in younger days to drop fruit from trees or shoot birds. It has a piston which is called a shuttle and 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 and is literally thrown upwards from the deck with a velocity higher than the minimum take-off. • SHort tAKE-oFF But ArrEstED-rECovEry (StoBAr). StoBAr systEm Is used with lighter aircraft carrying limited payload like Sukhoi Su-33 and MiG-29K which are normally employed for air superiority and fleet defence. This configuration has bow ski-jump and three arrestor wires on the stern of the angled deck. India’s INS Vikramaditya, which is currently undergoing a major refit in Russia, is of this type. • SHort tAKE-oFF vErtICAL-LAnDInG (STOVL). STOVL systEm CAn be used by Harrier Jump Jet family and Yakovlev Yak-38 which generally have very limited payloads, lower performance, and high fuel consumption, however a new generation of STOVL aircraft, currently consisting of the F-35B has much improved performance.
Electromagnetic Aircraft Launch System
Electromagnetic Aircraft Launch System (EMALS) is under development by the US Navy to launch carrier-based aircraft from catapults using a linear motor drive instead of conventional steam piston. EMALS consists of six subsystems working together and sharing components to power the four catapults on the ship. EMALS is being developed by General Atomics for Ford class carriers. The land-based prototype passed initial tests during 2010. The EMALS uses a linear induction motor (LIM), which uses electric currents to generate magnetic fields that propel a carriage down a track to launch the aircraft. A 91-metre LIM will accelerate a 45,000 kg aircraft to 240 kmph. The electric energy required by a LIM motor in a few seconds of its operations is much more than the power the mother ship can provide thus is achieved by a unique system of storing the power supply in its four disk alternators. It can also be recharged within 45 seconds of the launch as compared to the catapult which is much slower.
EMALS is designed to enlarge the operational capability of the US Navy’s future carriers to include all current and future carrier based lightweight unmanned to heavy strike fighters.
It provides higher launch energy capacity, easier system maintenance, improved reliability and efficiency, and better end-speed control. EMAL provides smoother acceleration at both high and low speeds which reduces the stress both on the aircraft and the ship. It also reduces the requirement of water. The Aircraft Launch and Recovery Equipment Program Office of the US Navy has recently reported that EMALS has completed shared generator testing. Further development and testing will continue so that EMAL can be fitted on Ford class carriers. Will the Indian Navy include EMALS in its Indian aircraft carrier programme?