This refers to Electro-Magnetic Aircraft Launching System, or EMALS, which will accelerate aircraft to flight speeds in very short distances. The aim is to replace the steam catapult currently used on aircraft carriers with a linear electric motor. The entire system should fit within the confines of the existing steam catapult. The advantages of such a system are increased operational availability, lower airframe stress due to programmable acceleration profiles, and reduced maintenance (and hence reduced manning).

1. A SEMINOR TOPIC ON
ELECTROMAGNETIC AIRCRAFT LAUNCHING SYSTEM
PRESENTED BY
D. PREM KUMAR

4. The basic concept discussing is to launch a aircraft with short take-off range
of distance on Navel Ships.
 To achieve high speeds with in 100’s of yards of ship deck is highly
complicate to a fighter jet ,such that we are using some external means of
systems to launch.
 Those systems will possess high thrust output within short period of time and
highly reliable to ship movements to high waves in the sea.
 At present the systems used are
1.Steam Launchers
2.Electric Launches

5. The basic concept discussing is to launch a aircraft with short take-off range
of distance on Navel Ships.
 To achieve high speeds with in 100’s of yards of ship deck is highly
complicate to a fighter jet ,such that we are using some external means of
systems to launch.
 Those systems will possess high thrust output within short period of time and
highly reliable with ship movements to high waves in the sea.
 At present the systems used are
1.Steam Launchers
2.Electric Launches

6. For over seven decades, the steam-powered catapult has been the standard
mechanism for launching airplanes from the decks of aircraft carriers.
Aircraft could not reach take-off speeds of over 180kmph in just a few seconds and
within a hundred feet, nor slow from landing speed to full stop in a similar time and
distance.
Cont…..

7. The existing steam catapults installed on U.S. carriers . Pistons within these connect
to the shuttle which tows the aircraft.
 The steam pressure forces the pistons forward, towing the shuttle and aircraft at
ever increasing speed until takeoff is achieved.
There is no doubt it works, as has been proven through the decades and in combat.
It can launch and retrieve aircraft of varying weights
at a rate of about one every minute or two and do so
simultaneously due to the angled deck.

8. why not continue with steam?
 It requires an enormous amount of energy to function, and it is energy-inefficient.
 It requires considerable maintenance and a large crew to keep it functioning, especially
in rough seas and potentially in combat conditions.
 It is bulky and heavy, while space is limited even on a modern carrier; it is an open-loop
system with no feedback to control its performance.
 It can only handle a limited range of aircraft types, weights and launch/landing
conditions The drawbacks includes the steam catapult requires a high volume of 1133 m3,
and a weight of 486 metric tons.

9. The new millennium have seen the development of an alternative technology for
launching aircraft, the electro-magnetic (EM) catapult.
 An EM launch system offers the requisite higher launch energy as well as substantial
improvements in performance, light weight, less volume & high efficiency.
The ability of an EM system to vary speed and thrust to meet the needs of the vehicle
being launched makes a single catapult suitable for a wide range of aircrafts.

10. 1.Linear Induction Motor:
 The EMALS uses a linear induction motor (LIM), which uses electric currents to generate magnetic
fields that propel a carriage along a track to launch the aircraft.
 The linear induction motor consists of a row of stator coils with the same function as the circular
stator coils in conventional induction motor.
 When energized, the motor accelerates the carriage along the track. The EMALS 300-foot (91 m)
LIM will accelerate a 100,000-pound (45,000 kg) aircraft to 240 km/h(150 mph).

11. Linear Induction Motor

12.  During a launch, the induction motor requires a large surge of electric power that
exceeds what the ship's own continuous power source can provide. The capacitors
that are being used in this application are two 250V 12,000µF.
 Each stator delivers up to 121 MJ (34 kWh) (approximately one gasoline gallon
equivalent this is faster than steam catapults).A maximum-performance launch using
121 MJ of energy from each disk alternator slows the rotors from 6400 rpm to
5000 rpm which is a fly wheel.
 The energy is recharged with in 45sec.The system
then releases that energy up to 484 MJ
in 2–3 seconds .
Energy Storage System:

13. During launch, the power conversion subsystem releases the stored energy from the
disk alternators using a cycloconverter.
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.
4.Control System:
Operators control the power through a closed loop system . Hall effect sensors on the
track monitor its operation, allowing the system to ensure that it provides the desired
acceleration.
The closed loop system allows the EMALS to maintain a constant tow force, which
helps reduce launch stresses on the plane's airframe
3.Power Conversion System:

14. Circuit Diagram :

15. The main principle used is Rail Gun Magnetic Effect which states
 The current flowing in the rails produces a magnetic flux density between the rails,
and this magnetic field interacts with the current flowing in the armature.
 The resulting Lorentz force accelerates the armature together with the projectile
along the rails.
Cont…..

16.  The capacitors that are being used in this application are two 250V 12,000µF which are not
capable of being fully charged by a regular power supply, to charge some voltage doublers are used
 The amount of charged stored is vary depending on weight of the armed carrier . Using PNPN SCR
triggering is applied.
 When current is flowing through the coil it generates a magnetic field around the piston that has an
opposing magnetic charge of the coil repelling it through the channel at very high speeds.
 Several switches are used in the circuit for safety including a charging switch and firing switch.
 The control system for this project will all be done through Lab View which will apply the 1.7V to
gate of the SCR to trigger the device.
 After charged with in 2-3sec the aircraft is launched up to the weight of 22,000kgs

18. Advantages:
 Compared to steam catapults, EMALS can control the launch performance
with greater precision, allowing it to launch more kinds of aircraft, from
heavy fighter jets to light unmanned aircraft.
 Lower operating costs.
 Require fewer people to operate.
 Deliver more percent of energy than a steam catapult's.
 90% power conversion efficiency.

19. disadvantages :
As in the case of EMALS ,air craft equipment is above the launch motor
which may be affected by the electro magnetic emissions (highly sensitive by
EMF).
Handling should be very careful due to high currents.
Highly skilled personal is required.
Initial cost is very high and Fault clearance take time.

20. Countries that are planning emals :
 United States
>EMALS was designed for and into the Gerald R. Ford-class aircraft carrier. And test runs on Feb 2020.
French
>Construction of the PANG is expected to begin around 2025 and will enter service in 2038.
 China
>According to a report in July 2017, the electromagnetic launchers used in the
Type 003 aircraft carrier. And about to launch in 2021.
 India
>The Indian Navy has shown an interest in installing EMALS for its planned CATOBAR super carrier
INS Vishal.
 United Kingdom
>UK were working on an electro-magnetic catapult (EMCAT) system for the Queen Elizabeth-class
aircraft carrier.

21. Applications :
StarTram is a proposed space launch system propelled
by maglev. The initial Generation 1 facility would launch
cargo only. More advanced technology would be required
for the Generation 2 system for passengers.
The name itself indicates Runway towards Stars

22. The idea is that by using electromagnetism to
accelerate a bullet, you can overcome the limitations
of gunpowder-style firearms, which generally top out
at muzzle velocities of about 2,000 meters per second .
Magnetic propulsion can in theory reach any speed; it is also
silent, and with no explosive gases to disperse it can have an
extremely high rate of fire.

23. Rail guns use magnetic fields created by high electrical
currents to accelerate a projectile to 5,400 miles an hour.
The velocity is sufficient to give the EMRG an effective
range of 110 nautical miles, or 126 miles on land.
A new warship, the large surface combatant, is
scheduled to eventually replace the Ticonderoga-class
cruisers.

24. Hyperloop is described as a sealed tube or
system of tubes with low air pressure through
which a pod may travel substantially free of air
resistance or friction. Virgin Hyperloop,in the
recent trial, two passengers - both company staff
- travelled the length of a 500m test track in 15
seconds, reaching 172km/h.

25. conclusion:
 The EMALS is a very good solution, being surprisingly small and simple , with a manageable power
electronics switching system.
 The mechanical systems does not appear to provide sufficient advantage to make the extra complexity
worthwhile, unless becomes a much more significant concern that has so far appeared.
 The EMLS offers the increased energy capability necessary to launch the next generation of
Applications in all sectors.
 The only limitation is the power handling capability and vibration resistance material.
 The challenge of this project will be to get the projectile up to a fast enough speed in a short time.
ANY QUERIES???....

26. Electricity – The Soul