Electromagnetic Aircraft Launch System: Difference between revisions
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*18 December 2010: Successful launch of a [[F/A-18E Super Hornet]] at [[Naval Air Engineering Station Lakehurst]].<ref>http://www.navair.navy.mil/NewsReleases/index.cfm?fuseaction=home.view&id=4468</ref><ref name="AFM275">{{cite journal|date=March 2011|title=USN undertakes first EMALS Hornet launch|journal=[[Air Forces Monthly]]|publisher=[[Key Publishing|Key Publishing Ltd]]|issue=Issue 275|pages=page 18|issn=09557091|accessdate=15 April 2011}}</ref> |
*18 December 2010: Successful launch of a [[F/A-18E Super Hornet]] at [[Naval Air Engineering Station Lakehurst]].<ref>http://www.navair.navy.mil/NewsReleases/index.cfm?fuseaction=home.view&id=4468</ref><ref name="AFM275">{{cite journal|date=March 2011|title=USN undertakes first EMALS Hornet launch|journal=[[Air Forces Monthly]]|publisher=[[Key Publishing|Key Publishing Ltd]]|issue=Issue 275|pages=page 18|issn=09557091|accessdate=15 April 2011}}</ref> |
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*June 1-2 2010: Successful launch of a [[T-45 Goshawk]]] at [[Naval Air Engineering Station Lakehurst]].<ref>http://www.navair.navy.mil/index.cfm?fuseaction=home.NAVAIRNewsStory&id=4620</ref> |
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*June 9-10 2010: Successful launch of a C2-A greyhound at [[Naval Air Engineering Station Lakehurst]].<ref>http://www.navair.navy.mil/index.cfm?fuseaction=home.NAVAIRNewsStory&id=4623</ref> |
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==Advantages== |
==Advantages== |
Revision as of 11:55, 17 June 2011
EMALS | |
End Speed | 28–103 m/s |
Max Peak-to-Mean Tow Force Ratio | 1.05 |
Launch Energy | 122 MJ |
Cycle Time | 45 seconds |
System Weight | < 225,000 kg |
System Volume | < 425 m³ |
Endspeed Variation | -0 to +1.5 m/s |
Electromagnetic Aircraft Launch System (EMALS) is a system under development by the United States Navy to launch aircraft from carriers using a linear motor drive instead of steam pistons used in conventional aircraft catapults. This technology reduces stress on airframes because they can be accelerated more gradually to takeoff speed than steam-powered catapults. EMALS also uses less fresh water, reducing the need for energy-intensive desalination.
Design and development
The EMALS is being developed by General Atomics for the U.S. Navy's newest Gerald R. Ford class aircraft carriers.
Linear induction motor
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.[1] The EMALS consists of four main elements:[2] The linear induction motor consists of a row of stator coils that have the function of a conventional motor’s rotor. When energized, the motor accelerates the carriage down the track. Only the section of the coils surrounding the carriage is energized at any given time, minimizing reactive losses. The EMALS' 300-foot (91 m) LIM will accelerate a 100,000-pound (45,000 kg) aircraft to 130 knots (240 km/h).[1]
Energy storage subsystem
The induction motor requires a large amount of electric energy in just a few seconds — more than the ship's own power source can provide. EMALS' energy-storage subsystem draws power from the ship and stores it kinetically on rotors of four disk alternators.[3] Each rotor can store more than 100 megajoules, and can be recharged within 45 seconds of a launch, faster than steam catapults.[1]
Power conversion subsystem
During launch, the power conversion subsystem releases the stored energy from the disk alternators using a cycloconverter.[1] 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.[3]
Control consoles
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 the launch stresses on the plane’s airframe.[1]
Program status
![](http://upload.wikimedia.org/wikipedia/commons/thumb/d/d4/US_Navy_101218-N-0000X-002_An_F-A-18E_Super_Hornet_is_launched_during_a_test_of_the_Electromagnetic_Aircraft_Launch_System_%28EMALS%29_at_Naval_Air_Sys.jpg/220px-US_Navy_101218-N-0000X-002_An_F-A-18E_Super_Hornet_is_launched_during_a_test_of_the_Electromagnetic_Aircraft_Launch_System_%28EMALS%29_at_Naval_Air_Sys.jpg)
- 18 December 2010: Successful launch of a F/A-18E Super Hornet at Naval Air Engineering Station Lakehurst.[4][5]
- June 1-2 2010: Successful launch of a T-45 Goshawk] at Naval Air Engineering Station Lakehurst.[6]
- June 9-10 2010: Successful launch of a C2-A greyhound at Naval Air Engineering Station Lakehurst.[7]
Advantages
Compared to steam catapults, EMALS weighs less, occupies less space, requires less maintenance and manpower, is more reliable, and uses less energy. Steam catapults, which use about 614 kilograms of steam per launch, have extensive mechanical, pneumatic, and hydraulic subsystems.[3] EMALS uses no steam, which makes it suitable for the Navy's planned all-electric ships.[8] The EMALS could be more easily incorporated into a ramp, which would reduce the aircraft’s takeoff speed and consequently the launch energy required.[3]
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.[8] EMALS can also deliver 122 megajoules of energy, 29 percent more than steam's approximately 95 megajoules.[3] The EMALS will be more efficient than the 5-percent efficient steam catapults.[1]
EMCAT
Converteam UK is working on a electro-magnetic catapult (EMCAT) system for the Queen Elizabeth class aircraft carrier.[9] In August 2009, speculation mounted that the UK may drop the STOVL F-35B for the CTOL F-35C model, which would mean the carriers being built to operate conventional (CV) take off and landing aircraft utilizing the UK-designed non-steam EMCAT catapults.[10][11] In June 2010, it was reported that the land-based prototype of the system had passed initial tests with the first aircraft launch from the system expected by the end of 2010.[12]
In October 2010, the UK Government announced it had opted to buy the future F-35C stealth fighter to fly off its carriers, using a CATOBAR system[which?]
See also
References
- ^ a b c d e f Schweber, Bill (2002-04-11). "How It Works" (PDF). EDN Magazine. Retrieved 2008-02-18.
- ^ http://www.ga.com/atg/EMS/m1346.php
- ^ a b c d e Doyle, Samuel, Conway, and Klimowski (1994-04-15). "Electromagnetic Aircraft Launch System - EMALS" (PDF). Retrieved 2009-01-14.
{{cite news}}
: CS1 maint: multiple names: authors list (link) - ^ http://www.navair.navy.mil/NewsReleases/index.cfm?fuseaction=home.view&id=4468
- ^ "USN undertakes first EMALS Hornet launch". Air Forces Monthly (Issue 275). Key Publishing Ltd: page 18. March 2011. ISSN 0955-7091.
{{cite journal}}
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has extra text (help) - ^ http://www.navair.navy.mil/index.cfm?fuseaction=home.NAVAIRNewsStory&id=4620
- ^ http://www.navair.navy.mil/index.cfm?fuseaction=home.NAVAIRNewsStory&id=4623
- ^ a b Lowe, Christian. "Defense Tech: EMALS: Next Gen Catapult". Retrieved 2008-02-27.
- ^ Converteam develops catapult launch system for UK carriers
- ^ "Britain rethinks jump jet order". UPI.com. Retrieved 2009-08-14.
- ^ Harding, Thomas (2009-08-05). "Defence jobs at risk". London: Telegraph.co. Retrieved 2009-08-14.
- ^ "Carrier Launch System Passes Initial Tests". Aviation Week.
External links
![](http://upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/30px-Commons-logo.svg.png)
- "Electromagnetic Aircraft Launch System - EMALS", GlobalSecurity.org