Simanaitis Says

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A TALE OF AIRCRAFT CARRIER TECHNOLOGY

I’M NOT surprised that the guy who prefers coal to renewables is also in favor of steam over electromagnetics. Indeed, his latest encounter with science and technology is textbook Trump.

At issue are the methods of launching and retrieving carrier aircraft. I note that my information on this comes from readily available Internet sources, likely not as deeply classified as briefings available to Trump.

Then again, even before his inauguration Trump told Fox News Sunday that he didn’t need daily intelligence briefings: “I’m, like, a smart person.”

We’ve heard this before.

“I’m, like, a really smart person,” Trump told a Phoenix rally in July 2015. “Trust me, I’m, like, a smart person,” he repeated when visiting CIA headquarters in January of this year.

Along with this is a Trump claim that “I know words, I have the best words. I have the best, but there is no better word than stupid.”

But back to aircraft carrier launches and retrievals.

Eugene Ely and his Curtiss approach arrestor ropes on the USS Pennsylvania, January 18, 1911.

The earliest launches of aeroplanes off water-based craft depended upon mechanical springs or compressed air. When ships evolved to have decks dedicated to launch and retrieval, for a time aircraft lifted off solely by their own power and, on return, continued to snag a cable with a tail hook.

A steam catapult on a conventional aircraft carrier.

By the mid-1950s, aircraft carriers had developed steam-operated catapults for launching larger, heavier aircraft. Steam-driven pistons travel in cylinders beneath the carrier’s slotted flight deck, hardware connecting the pistons to the aircraft being launched. Metal zipper-like surfaces along the cylinders help to recycle the steam pressure for the next launch.

Indeed, building up pressure takes more than a minute and is one reason for developing new catapult technology. Other reasons involve launching yet heavier aircraft, reducing stress on their structure during the launch and reducing maintenance requirements of the launch system.

The EMALS, Electromagnetic Aircraft Launch System, was conceived in 1999. In place of steam, its linear induction motor produces electric currents generating magnetic fields that propel a carriage along a track. It’s not unlike the technology propelling Maglev trains. As with a steam catapult, the carriage is linked to the aircraft being launched.

The hardware of an electromagnetically driven carriage beneath the carrier deck.

EMALS advantages are many: It’s inherently simpler than its steam counterpart, and thus easier to maintain. It recharges in 45 seconds, significantly less than a steam system’s turnaround time. An EMALS is programmed for a linear acceleration curve, which reduces the stress on the launched aircraft. It generates 29 percent more energy than its steam counterpart, thus launching heavier aircraft. Yet an EMALS can be tailored to launch everything from a unmanned drone to large aircraft.

By June 2014, the U.S. Navy completed EMALS prototype testing of 450 manned launches of its carrier-based aircraft. In May of 2015, shipboard tests began. The U.S.S. Gerald R. Ford, CVN 78, is expected to be commissioned later this year. It features both EMALS launch as well as an AAG, Advanced Arresting Gear which replaces the method of snagging aircraft that dates from the 1930s.

USS Gerald R. Ford, CVN 78, being developed as the most advanced aircraft carrier in the world.

On a traditional carrier, the kinetic energy of a returning aircraft is transferred by cable to a hydro-pneumatic damping device located below deck. An AAG replaces this device with a water-turbine feeding electricity into a large induction motor. The AAG can accept a wider range of aircraft, is less bulky and requires less maintenance than the device it replaces.

Advanced Arresting Gear hardware includes cables driving water-turbines, the electricity of which drives an induction motor.

However, these advanced features of CVN-78 are not without development complexities. In initial 2014 evaluations, EMALS testing recorded 201 failures out of 1967 launches; AAG testing revealed 9 failures out of 71 attempts.

Acting Navy Secretary Sean Stackley is quoted as saying on May 12, 2017, “Ford [the carrier] right now is on track to get out to sea before Memorial Day. We came out of builders’ trials strong. We are correcting those deficiencies… that we need to correct prior to going into Acceptance Trials (AT). I’m pretty confident right now in a good AT and a quick turnaround to delivering the ship.”

What’s more, in a May 11, 2017, article in Atlantic, it’s noted that “… the problems with the Ford-class carrier program are more organizational than technological.”

Also, it’s known that China is developing an aircraft carrier with these features, as are France and India with U.S. components.

By contrast, what follows is Trump’s scientific analysis of launch options, as offered in a Time interview and reported by the Navy Times:

In discussing this digital launch system, Trump said, “It sounded bad to me. Digital. They have digital. What is digital? And it’s very complicated, you have to be Albert Einstein to figure it out. And I said—and now they want to buy more aircraft carriers. ‘What system are you going to be—’ ”

“ ‘Sir, we’re staying with digital.’ ”

“I said, ‘No, you’re not. You’re going to goddamned steam, the digital costs hundreds of millions of dollars more money and it’s no good.”

It’s not difficult to image steam coming out his ears when Trump made these scientific pronouncements. ds

© Dennis Simanaitis, SimanaitisSays.com, 2017

5 comments on “A TALE OF AIRCRAFT CARRIER TECHNOLOGY

  1. Henry Nelson
    May 17, 2017

    Both the emals and especially the arresting system have been developmental disasters. The sanguine assessment of Stackley doesn’t properly acknowledge the continuing troubles of both systems. Neither is ready for prime time even though the ship is several years late already. Can’t something like this be developed in 20 years? Apparently not.
    Unfortunately, steam is not an option. The Ford class carriers are designed for electric systems. Heavy conductors don’t convert to carrying steam. They have to make it work.

  2. Mr.
    June 18, 2017

    You’ve taken another shoot at Trump. Frankly your blog was better before it became political.

    The issue isn’t Trump, but the fact that AAG doesn’t work. You can talk all the theory you want but an aircraft carrier exists to serve as a mobile airstrip. If a carrier can’t launch planes it’s useless. There is currently one non-functioning carrier undergoing trials, and two in the hopper that will also rely on AAG. Redesigning the carriers to use steam catapults will cost millions, or maybe hundreds of millions. I agree with Mr. Nelson that the Navy has to make AAG work, but how long will that take? Sometimes a functioning low-tech solution trumps a non-functioning high-tech solution.

    • simanaitissays
      June 18, 2017

      Thanks for your views. On the other hand, buggy whips worked a lot better than the first automobiles. Coal worked better than the first solar cells.
      As for the website’s occasional political postings, it’s part of my planned “and other stuff.” These day, very important stuff. From time to time, such postings will continue to appear.

  3. Mr.
    June 18, 2017

    I doubt that many people who needed transportation traded their working horse and buggy for a non-working automobile.

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