US Navy's plane-hurling mass driver in tech hiccup

Discussion in 'Americas' started by nandu, May 13, 2010.

  1. nandu

    nandu Senior Member Senior Member

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    US Navy's plane-hurling mass driver in tech hiccup

    Software blamed for electro-catapult backfire

    Radical plans by the US Navy to equip its next aircraft carrier with electromagnetic mass-drivers for launching aircraft instead of the traditional steam catapults have hit technical snags.

    The so-called Electromagnetic Aircraft Launch System, or EMALS, is now under development in a shore-based test facility at Lakehurst naval air station in New Jersey. However, according to reports, the test mass-driver installation suffered serious damage earlier this year in a mishap blamed on a "software malfunction". Apparently the "shuttle" - which moves along the catapult track to accelerate a plane to flying speed - went the wrong way in a test shot and smashed into important equipment.

    The Newport News Daily Press, reporting on an interview with EMALS programme chief Captain Randy Mahr, says that the accident has delayed the shore-based testing by several months. It had been planned to commence launching aircraft - as opposed to test loads - this summer, but that will not now happen until autumn.

    The next US supercarrier, CVN 78, aka USS Gerald R Ford, is now under construction and intended to join the fleet in 2015. Navy officials confirmed last year that it is now too late to amend the ship's design and revert to steam catapults: EMALS must be made to work or the US Navy will receive the largest and most expensive helicopter carrier ever.

    Mahr says that the EMALS mishap won't delay the Ford's arrival, as the hardware is ready for installation on schedule. He is confident that remaining software problems can be rectified after the kit is in place.

    "The hardware issues we're comfortable with," he told the Daily Press. "The things that are delaying me right now are software integration issues, which can be fine-tuned after the equipment is installed in the ship."

    Mahr had been supposed to hand over the EMALS to another officer and move on to another job by now, following his selection for promotion last year. However, sceptical politicians in Washington, seeking to increase accountability in the event of potentially disastrous failures by the project, have demanded that he remain in post past his normal time.

    Present-day catapult carriers, operated only by the US and France, use steam generated by their nuclear propulsion to power their aircraft launchers. The steam catapult was actually a British invention, but the Royal Navy has not had conventional fixed-wing carriers since the 1970s for reasons of cost, instead being limited to more basic ships carrying helicopters and vertical-landing Harrier jumpjets.

    Steam catapults are hard on the planes they launch, require a lot of maintenance and manpower, and are bulky and heavy as well. The USN wants to move to EMALS as it should be cheaper to run, less burdensome on the ship and less damaging to aircraft. The electromotive launchers are more flexible and controllable, too, and are expected to be capable of launching lightweight unmanned aircraft as well as new and heavier naval aircraft of the future which steam cats couldn't manage.

    EMALS is also of great interest to the Royal Navy, as the new British carriers now under construction will have space in their hulls for catapults to be fitted, though under current plans none will be. At the moment the idea is that HMSs Queen Elizabeth and Prince of Wales will carry F-35B supersonic stealth jumpjets, though it is looking more and more as though the cash-strapped MoD will be unable to afford a suitable number of these complex and expensive planes.

    The British ships can't easily be equipped with steam catapults as they are to be gas-turbine powered and so will be unable to generate steam. They could perhaps be upgraded to nuclear propulsion, but this would be costly upfront (though potentially saving money overall in time as cheaper planes could then be bought). With the MoD so short of money this decade, though, this is highly unlikely to happen.

    But if EMALS can be made to work reasonably soon, the option would be there for the UK to buy it for the Royal Navy: the Queen Elizabeth class are to have electric transmissions, so they could easily power an EMALS launcher. Britain could then cancel its purchase of expensive F-35B jumpjets.

    The carriers could instead be equipped with somewhat cheaper F-35C tailhook stealth planes, or even existing F-18s - much more affordable. It would also be possible to buy existing Hawkeye catapult radarcraft as used by France and America, avoiding the need to custom-develop a pricey vertical-landing radar bird to replace today's ageing AEW Sea Kings.

    In fact, the success or failure of EMALS could have a hugely greater effect on the capability of British carriers than on America's. The ability or inability of the Ford to launch jets will a noticeable factor in the US Navy's air punch from 2015 on; but the difference between a future Fleet Air Arm equipped with numerous off-the-shelf aircraft and one with a tiny force of F-35B jumpjets is a lot bigger.

    None of that means that the Royal Navy will definitely buy EMALS if it becomes available; but even so, one can be sure that a lot of British naval officers in MoD headquarters are watching the project's progress with interest.

    http://www.theregister.co.uk/2010/05/12/emals_backfire/
     
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  3. Rebelkid

    Rebelkid Regular Member

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    Is this like shooting an aircraft like a bullet ?
     
  4. nandu

    nandu Senior Member Senior Member

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    Carrier Launch System Passes Initial Tests

    [​IMG]

    Recent tests at NAS Lakehurst, N.J., should have builders of the USS Gerald R. Ford (CVN-78) sleeping more easily. The Navy’s risky bet in the design of the Ford—its reliance on an all-electric replacement for the steam catapult—appears to be paying off.

    Problems and delays with the electromagnetic aircraft launch system (Emals) last year were a threat to the carrier, because its design and construction reached a point where reverting to steam would have been difficult and expensive. With Emals in mind, the Ford-class features a much more powerful electrical generation and distribution system than the predecessor Nimitz-class ships, along with the virtual elimination of steam-energized services such as heating, galleys and pumps and 10 km. (6 mi.) of steam lines.

    The Navy has delayed delivery of the $11.5-billion carrier for budgetary reasons twice. (Commissioning is expected in September 2015.) The scheduled progress of Emals now matches the carrier’s build schedule but with so little slack in some areas that the Navy is continuing to monitor development of the system closely.

    The land-based prototype of Emals at Lakehurst started high-speed “no load” test runs in April, and will start to accelerate with dead loads—ballast—at speeds increasing from 50-180 kt. At prime contractor General Atomics’ plant in Tupelo, Miss., prototypes of the Kato Engineering power modules are undergoing accelerated life testing, performing 6,800 power cycles. So far, tests show no signs that the powerful electrical surges cause electromagnetic interference with aircraft, ammunition or ejection seats. The first aircraft launch at Lakehurst is expected by year-end.

    Initial Emals components for Ford are due at the Newport News shipyard in May 2011. The tightest schedule concerns the 12 power units, which are high-speed motor-generators weighing 80,000 lb. each and functioning as flywheel energy storage and release units. Some are not due at the yard until the day before they are installed.

    Emals will deliver energy more flexibly than Nimitz-class steam catapults. The F-35C Joint Strike Fighter demands more launch energy than the F/A-18E/F, and Emals will allow the Ford to launch the JSF at maximum weight with less wind-over-deck.

    Emals can also be set to lower energy levels than a steam catapult, allowing it to launch small, lightly loaded aircraft like unmanned aerial vehicles.

    The Ford class features a new advanced arrester gear as well, also produced by General Atomics and replacing hydraulic rams with a water turbine and induction motor, permitting a finer setting of arresting force and reducing the need for manual adjustments between landings. Like Emals, it is expected to allow the carrier to operate heavier and lighter aircraft than the current Mk. 7 arrester gear. Unlike Emals, it is intended to be backfitted to Nimitz-class carriers.

    The carrier will be part of the process of introducing a landing guidance system to the Navy: the Joint Precision Approach and Landing System (Jpals). It will be one of the first ships with Jpals, which is slated to be on all carriers and large amphibious transports by 2018. The second Ford-class ship, CVN-79, is due to be the first carrier without SPN-41 and SPN-46 radars, which provide carriers with an automatic landing capability.

    Adoption of Jpals is urgent for the Navy because current radars will not be supportable after the early 2020s. Jpals is also associated with the F-35C, because the fighter’s reduced radar cross-section means that current radar-based autolanding systems cannot acquire it. The installation of Jpals on carriers will match service entry of the F-35C.

    The first increment of Jpals will be qualified for flight guidance down to 200 ft. and 0.5-mi. visibility. Accuracy is intended to be sufficient for an automatic landing, and that capability is being demonstrated as part of the Northrop Grumman X-47B Navy Unmanned Combat Air System program.

    The key to its accuracy is shipboard-relative GPS, which uses two GPS receivers—one forward of the island on the starboard side and the other on the portside stern. The space between the sensors and their relative location allows the system to measure the position of the ship accurately and track its movement—speed, pitch, roll and heave—with the aid of three Northrop Grumman LN-270 inertial reference units. Using the same differential GPS technique, Jpals also provides an accurate aircraft position. A data link allows the system to transmit automatic landing guidance.

    http://www.aviationweek.com/aw/gene...ne=Carrier Launch System Passes Initial Tests
     

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