EMALS (ELECTRO MAGNETIC AIRCRAFT LAUNCH SYSTEM)

 

The NDA government has been stressing on fortifying India’s relationship with global powers to realize its dream of an empowered India. Elaborate plans to revolutionize aging Indian industries have been drawn up. These ambitious plans are strongly dependent on foreign players.  The government is all set to attract global partners. Not only to invest in India, but also to co-develop and co-produce indigenously. The highlight in India’s modernization plans are the aging defence industries. Over the years, India has focused towards the western market moving far away from its traditional partner Russia.

The relationship between India and America has been an all time high, since the NDA came to power. The governments have adopted the motto “Chalein Saath Saath: Forward Together We Go”. The governments have now set steer to renew bilateral ties in trade, commerce, banking, industries and military systems.  Several key projects centralized around the ‘Make in India’ initiative have been concluded. Both the governments have agreed to work closely for revolutionizing India’s defence industry. The US-Indian government and military command believes in government by rule of law, freedom, and democracy. India and US forces form a major part of UN peacekeeping forces and have been working relentlessly to address security issues throughout the globe.

The military commands of both nations have been working towards maintaining security and stability in the world. Plaqued with repeated terror strikes, India and US have been working towards defeating violent religious extremism and terrorism. India and US have started working towards preventing the spread of weapons of mass destruction, materials and technologies, which may hamper world peace and protecting the free flow of commerce on planet earth.

 

During the visit of the President of United States of America to India, several key projects were cleared for co-development and co-production under the ‘Make in India’ initiative. The relations of Indo-US defence industries were formed around Defence Trade and Technology Initiative (DTTI). Initiated in 2012, DDTI was to pave way for a self reliant India. The cumbersome procurement and off-set clauses mandated under the DTTI had driven away investments from key global partners.

Narendra Modi has promised a new era in the Indo-US relationship under his ambitious ‘Make in India’ initiative. The initiative has already been accepted throughout the world with pomp and honour. A self reliant India has been promised and is the being delivered with every concluding deal. India and US adopted the ‘Make in India’ initiative during Modi’s visit to US. The military commands of the countries have indentified four “pathfinder projects” which will be the bedrock for future relations. India and US will now co-produced ‘Raven mini unmanned aerial vehicles (UAVs)’, “roll-on, roll-off” intelligence-gathering and reconnaissance modules for C-130J Super Hercules aircraft, mobile electric hybrid power sources and chemical-biological warfare protection gear for soldiers.

USA has also been very vocal in supporting India to gain an upper hand in the Asia-Pacific region. China’s presence in the Pacific theatre has been a key concern for USA. Being a security partner for various island countries in the Pacific Ocean, USA has failed to check the aggressive Chinese navy.  USA has also realized the need for a regional power which is capable of checking the PLAN right in its path. The only regional power which posses the might to check the ever adventurous Chinese is India.

EMALS catapult run out 23rd October 2009

India has its share of disputes with China in the Indian Ocean Region. The conflict between the neighbours has escalated with India turning out to be a key security provider in the IOR region. Indian navy is on a spree of procurements and modernization to check the PLAN. Sharing the common concern and enemy, US and Indian navy have now agreed to work more closely to maintain sanity in the oceans. The Commander of US’s Pacific fleet has also requested Indian Navy to join the efforts of checking the adventurous Chinese. Obama during visit had asked India to stand out openly in the South China issue.

Indian Navy has received substantially help from its US counterpart in its mission for modernization. Indian navy is currently in the transition from a regional power to a ‘blue water’ navy that can operate in threat theatres across the world. An integral part of India’s ‘blue water’ dreams, is its eagerness to operate a three pronged CBG (Carrier Battle Group).  Even though the operations of a three pronged CBG may prove out to be a burden, the need is substantiated. Sharing its territory with two highly volatile neighbours, India needs to secure its Eastern and Western sea fronts at the same time.  Hence the plans of one CBG serving on the western and other on the eastern water fronts and another in docks for maintenance seems a logical solution.

India is an experienced CBG operator and has been the only other nation than USA in the recent past to have operated a two front CBG. The carriers operated by the Indian Navy are of STOBAR (Short Take Off But Arrested Recovery) configuration. Operating a STOBAR configuration carrier launching of heavier surveillance aircrafts has been a headache for the IN. It is crucial to operate reconnaissance missions but this requires the ability to launch heavier aircrafts and this in turn requires using the CATOBAR (Catapult Assisted Take-Off But Arrested Recovery) system. Under the IAC (Indigenous Aircraft Carrier) project, Indian navy is procuring the IAC-I in a STOBAR configuration.  The recently constituted IAC-II project is being planned to be configured with the CATOBAR systems. The latest addition to the CATOBAR systems is the US pioneered EMALS system.

The Electromagnetic Aircraft Launch System (EMALS) is an aircraft launch technology being developed by General Atomics for the United States Navy, which will be fitted on the newest Gerald R. Ford-class aircraft carriers. This system will replace the steam propelled catapult aircraft launch system on the Nimitz aircraft carrier. EMALS has passed all initial tests without any major glitches. US navy currently uses steam propelled catapults for launching aircraft. The current catapult system requires about 615 kg/ 1,350 pounds of steam for launching a single fighter jet off the deck. The steam required for the launch process is produced by using super heated coils placed in the nuclear reactors. High amount of purified water has to be piped to nuclear reactors. The maintenance of this system is extremely demanding and is costly.

As an answer for this concern, US has introduced the EMALS system. EMALS is an electric driven launch system which promises to gradually scale down the maintenance required for launching aircraft. EMALS is based on generation and utilization of electric current rather than the old practice of using steam.  The whole system works on the principle of Electromagnetic induction.

The major components of EMALS are –

  • Linear induction motor
  • Energy storage subsystem
  • Power conversion subsystem
  • Control Consoles

4-5-2004

 

Linear induction motor

Current when produced propels a regular electric motor in a circular motion. The launch of an aircraft is based on the catapult which has to be propelled in a straight line. This can be achieved with the use of Linear Induction motor which produces rectilinear motion.  A linear electric motor typically consists of a flat magnetic core with transverse slots which are often cut straight and with coils laid into slots. Each phase gives an alternating polarity, so that the different phases physically overlap each other. In an induction motor, the force is produced by linearly moving magnetic field acting on conductors in the field. Any conductor – be it a loop, a coil or simply a piece of plate metal, that is placed in this field will have eddy currents induced in it thus creating an opposing magnetic field, in accordance with Lenz’s law.

When energized, the motor accelerates the carriage down the track and the carriage in turn takes the aircraft along and propels it off the deck. With the charge being inducted into the motor only the section of the coils surrounding the carriage is energized. With only the coils being energised the reactive losses is minimised to a very great extent. With the LIM EMALS can accelerate an aircraft of around 45000 kgs to about 240 km/h.

Energy storage subsystem

To propel the carriage at the speed required the induction motor requires very large amount of electric power. The current required to attain this speed required production of current which is actually more than the power that can be obtained from the ship’s own power source. The EMALS is therefore put with an energy-storage subsystem which draws power from the ship’s main power source and stores the procured energy kinetically on rotors armed with four disk alternators. This energy is then stored and the alternators running and the process repeats till the need for an aircrafts launch is felt. When the systems are activated for the launch of an aircraft the system releases the stored energy in a very short period of time as against the time required for production of steam in the traditional stem propelled catapults. Each rotor can easily store more than 100 mega joules of energy. To reduce the time betweens launch of each aircraft it the system has been configured to be recharged within 45 seconds of a launch which is way faster than steam catapults.

Power conversion subsystem

With the help of the linear induction motor, the produced energy is stored in Energy storage subsystem. After the energy is stored, it is crucial for the same energy to be released when a launch is required. The basic function of the power conversion subsystem is to release the stored energy in the energy storage subsystems during launch. This is brought about by using a cycloconverter. A cycloconverter is used to covert a constant voltage, constant frequency AC waveform to another AC waveform of a lower frequency by synthesizing the output waveform from segments of the AC supply without an intermediate DC link. The cycloconverter provides a controlled rising frequency and voltage to the LIM, energizing only the small portion of stator coils that affect the launch carriage at any given moment.

 

Control consoles

It is crucial for the EMALS to be controlled and monitored constantly and it is also crucial to maintain a constant voltage for the LIM and to look make sure the launch of the aircrafts to be an uninterrupted process. This whole process is brought about by control units which are responsible for control through closed loop structure. And this in turn allows the operators to maintain a constant tow force that reduces the stress on an aircrafts airframe to a large extent.

The IAC-II is in advanced stage of planning and is rumoured to be propelled by nuclear fuel. Also the carrier is being rumoured to be around 65000 tonnes which makes the IAC-II the heaviest Indian build ship. The main focus of a CBG is to extend the reach of the countries forces. But India has never been in the global race for projecting a control regime environment. Even after the carrier is inducted its area of operation may only be around the IOR or the EEZ. If the CBG is charged with the safeguarding of EEZ then reconnaissance is going to be an important part of the CBG’s daily routine. This requires the launch of heavier aircrafts like the E-2D Hawk eye that is to be part of the carrier’s air wing. This means the navy has to opt for a CATOBAR configuration. But with the EMALS being a very newly introduced system it has to be seen if the Navy command goes with the EMALS or opts to the more proven ‘ steam propelled’ catapults to launch these aircrafts.

 

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