Navy to test electromagnetic catapult on carrier

[Chieftain]

http://www.foxnews.com/tech/2014/05/14/navy-to-test-electromagnetic-catapult-on-carrier/

The Navy is preparing to launch the first ship-board tests of a new Electromagnetic Aircraft Launch System designed to replace steam catapults and propel fighter jets and other aircraft off the deck of an aircraft carrier and into the sky over the ocean, service officials said.

The EMALS system, which uses an electromagnetic field to propel aircraft instead of the currently used steam catapult, is slated for the new Ford-class aircraft carriers. The first EMALS system has been under construction for several years aboard the USS Gerald R. Ford (CVN 78), the first in class of the new carriers expected to deliver to the Navy in 2016, Navy officials said.

This summer, the Navy will start incremental testing on board the USS Ford wherein “dead loads” placed on weighted sleds are catapulted by the EMALS system into the river, said Capt. Jim Donnelly, program manager for aircraft launch and recovery equipment.

“As things get connected they will increase the number of tests. The first aircraft launch will be after the ship gets to sea,” Donnelly said.

Ship integration and testing for the EMALS technology will mark a substantial milestone in a program which, until now, has largely been conducting land-based flight tests at a Navy facility in Lakehurst, N.J.

“We’ve conducted 452 aircraft launches and just finished up our second phase of aircraft compatibility testing,” Donnelly explained.

The ground-based EMALS catapult tests have launched EA-18G Growlers, F/A-18 Super Hornets, C-2 Greyhound planes and E2D Advanced Hawkeyes, among others. In fact, EMALS even launched an F-35 Joint Strike Fighter at Lakehurst, Donnelly added. The USS Ford has been under construction in recent years at Newport News Shipbuilding, a division of Huntington Ingalls.

Equipment for the EMALS system has been in development on board the ship for several years, Navy officials said. General Atomics was awarded a $573 million deal from the Navy in 2009 for EMALS development.

“We’ve been making component deliveries to the ship in Newport News since 2011. It started early because for EMALS, some of the equipment such as the motor-generators are lower in the ship so they had to be part of the super-lift early on,” Donnelly added.  “At this point we’re delivering components to be installed in the catapult trough which is up on the flight deck.”

Metal decking is slated to be placed over the trough on the flight deck. Donnelly said cabling and linear induction motor sections are still being installed on board the USS Ford. The linear motors are engineered to help create a sequentially activated rolling magnetic field or wave able to thrust or propel aircraft forward, Donnelly explained.

“It is the same type of technology that you see in a rollercoaster except this one is designed for critical launch reliability. It has to work every time you press the launch button. You are getting an electromagnetic field by turning on linear motor sequentially so we don’t energize the whole field in one shot,” he explained.

The electromagnetic field acts on a large 22-foot long aluminum plate, he added. The aluminum plate runs in between stationary sections of 12-foot long linear motors. Electricity runs through the two sides of the motors, creating an electromagnetic wave, Donnelly explained.

“The aircraft motors are kicked in at the beginning. There’s a hydraulic piston that pushes a shuttle forward. The shuttle is what connects to the aircraft launch bar,” Donnelly said.

The EMALS system is engineered to be both steady and tailorable, meaning it can adjust to different aircraft weights and configurations, Donnelly said.  For example, EMALS is configured such that it could launch a lighter weight aircraft, such as an unmanned aircraft system, he added.

This is particularly useful because the amount of thrust needed to launch an aircraft depends upon a range of interwoven factors to include size, shape and weight of the aircraft, wind speed on the carrier deck and the speed of the aircraft carrier in the water, Donnelly explained.

“EMALS better supports the air wing now and in the future. As you may know we’ve changed the make-up of the carrier wing over the years. We’re getting to an air wing that requires higher energy launches and EMALS is much more capable when it comes to higher launch energy requirements,” Donnelly said.

[Chieftain]

This is what I did on active duty in the Navy.  I was on the catapult test team for two Nimitz Class carriers, USS Theodore Roosevelt CVN-71 and USS George Washington CVN-73.  There is little in the world that is more fun than shooting a 100,000 lbs deadload off the flight deck at 150 knots into the river.  It makes the biggest gawd-awful splash you can imagine, then bobs back up to the surface to float, where it is recovered and launched again.  The best part is that there are a whole series of weights of deadloads and you have to shoot all of them multiple times for each catapult certification. 

EMALS is as  big of a technological leap forward as the introduction of the steam catapult was.  The weight of the machinery required for steam catapults in incredible and the savings in space alone will increase the Ford's capabilities substantially.  The nuclear power plants are completely different than any other afloat, as the system needs to produce large loads of electricity instead of hotel steam for the catapults.

I'm pretty sure there will be some amazing video of these deadload tests coming up....

 

[Oceander]

This is what I did on active duty in the Navy.  I was on the catapult test team for two Nimitz Class carriers, USS Theodore Roosevelt CVN-71 and USS George Washington CVN-73.  There is little in the world that is more fun than shooting a 100,000 lbs deadload off the flight deck at 150 knots into the river.  It makes the biggest gawd-awful splash you can imagine, then bobs back up to the surface to float, where it is recovered and launched again.  The best part is that there are a whole series of weights of deadloads and you have to shoot all of them multiple times for each catapult certification. 

EMALS is as  big of a technological leap forward as the introduction of the steam catapult was.  The weight of the machinery required for steam catapults in incredible and the savings in space alone will increase the Ford's capabilities substantially.  The nuclear power plants are completely different than any other afloat, as the system needs to produce large loads of electricity instead of hotel steam for the catapults.

I'm pretty sure there will be some amazing video of these deadload tests coming up....

 

making stuff go "boom" or "smash" is always fun!

[SPQR]

EMALS Rail

[EC]

Idle thought - I mean obviously it works, with so many successful test launches, but how on earth do they stop the magnetic field spike screwing up the flight instruments and computers on the planes?

[SPQR]

Idle thought - I mean obviously it works, with so many successful test launches, but how on earth do they stop the magnetic field spike screwing up the flight instruments and computers on the planes?

There is some information here

http://www.foxnews.com/tech/2014/05/14/navy-to-test-electromagnetic-catapult-on-carrier/

[Chieftain]

making stuff go "boom" or "smash" is always fun!

Boom yes, smash no.  Thankfully I never put a plane in the water on my watch.

 

[Chieftain]

Idle thought - I mean obviously it works, with so many successful test launches, but how on earth do they stop the magnetic field spike screwing up the flight instruments and computers on the planes?

Not sure of the details, but military aircraft are already hardened against EMI, and from the looks of the trough they probably generate a fairly tight field exactly when and where it is needed.  As I understand it, the shuttle assembly is stopped by reversing the electrical field at the end of the catapult, instead of using massive (and heavy) waterbrakes.



That's a picture courtesy of Wiki of the Charles Degaulle's C-11 steam catapult being worked on.  You can see the power cylinders in the trought with the deckplates still installed.  The water brakes and power pistons have been removed, and the round object in the foreground is the back of the aluminum piston on one of the piston assemblies.  It is pointing the opposite direction it would be installed.

I can't stress how big of a departure this is for aircraft launching and carrier design.  In WWII the Navy used hydraulic catapults...the equipment was mounted below the hangar bay and used tensioned cables to run the launching engine.  When jets came along the British Navy had already invented the steam catapult and sold the design to the Yanks, and it had the power needed to get those jets up to minimum flying speed.  The US Navy has improved and enlarged the original C-7 steam cat to the current C-13-2 that is installed on late model Nimitz Class carriers. 

But the increased power has an enormous weight penalty.  Everything on the ship affects "weight and moment", and a steam catapult installation has an enormous impact on how the carrier is designed.  The nuclear reactors on a Nimitz class are designed to produce enormous amounts of hotel steam for the main engines and the steam catapults.  In that trough you are looking at would normally be installed a pair of 18" ID steam cylinders, like a big double barreled shotgun.  It has heavy removable deckplates that are bolted in place over the cylinders.  There is an extensive hydraulic system to operate and control each catapult, and a massive steam receiver tank that is half filled with superheated water and piped to the end of the catapult.

But EMALS is a whole different breed of cat.  As I understand it, the launching engine is powered by a generator/flywheel that is spun up to a particular speed to give "X" amount of energy to the coils, and when the catapult is fired the generator set discharges to the launching engine in the 2-3 seconds it takes to tow the plane down the track 300 feet...

There is no massive steam system, no need for a hydraulically powered retraction engine or water brakes.  That means the ship can carry a lot more beans, bullets, bombs and jet fuel, which means the ship can stay at sea operating well beyond the capabilities of any Nimitz class hull.

Enormous leap forward in Naval technology, and Naval Air Systems.  EMALS will be as revolutionary as the steam catapult was when it was first introduced in the fifties by the British....

 

[EC]

Thank you, Chief!  Figured if anyone would know, it'd be you! 

Never actually considered the whole change in weight distribution aspect. They must have to be redesigning next gen carriers from the keel up again. And of course, with less inert mass hanging there just under the flight deck, she's going to be significantly more nimble than the Nimitz class. Maybe not turning on a dime, but certainly on a quarter. Probably a lot more stable as a landing platform too, since most of the heavy stuff can do double duty as ballast.

The other thing I like about this - You have full launch capability with no reduction in available engine power, since they are no longer sharing the steam.