EMALS & JPALS for the JSF

[splittingatoms]

The use of DC is probably because they don't have the technology to make AC work. It's a step back in my opinion. The auto industry abandoned DC for similar applications long ago because of the problems and expense of maintaining those systems.

From published reports the reactors on the Fords put out around 770MW compare to 525 or so on the Nimitz class. They're comparable to those in domestic power plants that are rated at 800MW. They may be smaller in size

Long time lurker (couple years now), first time poster.

I just want to chime in here on something I know pretty well (nuclear power plants)...the Ford plants likely have a thermal output (MWt) in the range posted. However, their electrical/propulsion output is probably around 28-30% of that. So let's assume maybe 215-230 MWe (288,000-308,000 HP).

A single-core, commercial nuclear power plant will range anywhere from about 1600 MWt for a small, two-loop plant to 4500 MWt for an EPR or APWR type plant. That will give electrical output in the range of 580-1700 MWe (775,000-2,275,000 HP).

[tincansailor]

Long time lurker (couple years now), first time poster.

I just want to chime in here on something I know pretty well (nuclear power plants)...the Ford plants likely have a thermal output (MWt) in the range posted. However, their electrical/propulsion output is probably around 28-30% of that. So let's assume maybe 215-230 MWe (288,000-308,000 HP).

A single-core, commercial nuclear power plant will range anywhere from about 1600 MWt for a small, two-loop plant to 4500 MWt for an EPR or APWR type plant. That will give electrical output in the range of 580-1700 MWe (775,000-2,275,000 HP).

[/quote]

Welcome aboard splittingatoms. Interesting analysis. So a DC system would give you greater Shaft Horse Power? I was discussing this a couple of weeks ago with another old navy guy, with engineering experience. He was surprised the Chinese would try this because of the greatly added weight of generators, need for thicker wiring, and insulation, and safety issues. But your suggesting it may be worth it?

My thought was the breakthrough the Chinese were referring to might be room temperature super conductivity. We haven't heard much about that technology lately, but if they have made that kind of breakthrough it would solve some problems with the weight, but not the safety issues. What are your thoughts on the subject?

[wolfpak]

Splittingatom,

Thanks. I stand corrected. My 800 MW should have been qualified as electrical power out the door at one of the Midwest utilities. Mixing apples and oranges.

[splittingatoms]

Welcome aboard splittingatoms. Interesting analysis. So a DC system would give you greater Shaft Horse Power? I was discussing this a couple of weeks ago with another old navy guy, with engineering experience. He was surprised the Chinese would try this because of the greatly added weight of generators, need for thicker wiring, and insulation, and safety issues. But your suggesting it may be worth it?

My thought was the breakthrough the Chinese were referring to might be room temperature super conductivity. We haven't heard much about that technology lately, but if they have made that kind of breakthrough it would solve some problems with the weight, but not the safety issues. What are your thoughts on the subject?

Sorry if I wasn't clear. My analysis was merely comparing the size of commercial scale plants to naval plants and making sure the difference between thermal and electrical Megawatts was understood and called out.

As far as AC or DC power for EMALS (and the like), I can't say I see any one system being superior or "cutting edge" over the other. Three phase, AC power has a lot of advantages in rugged simplicity. Power electronics can be minimized in many systems, voltages steeped up or down as needed, and motors can be off the shelf. DC power offers the potential for minimized transmission losses, however I'm not sure how much that buys you on a ship. Doing voltage transformations in DC is very well-established at this point, but it isn't as rugged or cheap as a transformer in my opinion (I am open to be wrong on this). I would imagine the EMALS system has DC as some point which is then put through something looking a bit like a giant audio amplifier to drive the linear motor. In the sense that a massive amount of power can undergo one less transformation, perhaps it's a benefit. With that said, the EMALS flywheels could already accomplish that with the right kind of motor/generator, i.e. taking in AC to spin them up and then outputting DC. Long story short, choosing DC doesn't illustrate any advantage or disadvantage in my eyes, nor does it make or break the coupling to conventional power sources.

As has already been mentioned, diesels and gas turbines are more than capable (actually more so than nuclear) of shifting power to meet demands. Like the Zumwalt has lots of extra electrons for lasers/railguns/etc., adding additional generation capacity for EMALS strikes me as no big deal. A single added LM2500 or MT30 turbine is a very small addition to the layout of the ship and is MORE than capable of running EMALS. It could even sit dormant until one wishes to launch aircraft and then be brought into action. I simply attribute the article above to typical journalist incompetence.

Perhaps the "innovation" is the use of high temperature superconductors. These certainly exist and work to bring sizes down. I can once again point to the Zumwalt, which has the largest superconducting motor on the face of the earth. It has also struggled with that FOAK technology and I'm sure a linear motor up on the deck would be even more "adventuresome" from a qualification and refinement perspective. HT superconductors still require liquid nitrogen for cooling, so there is a whole subsystem of cryo equipment and insulated lines which must exist. Leaks in these systems can be catastrophic to personnel safety and to other equipment. They can also cause the superconducting equipment to not superconduct. Should this happen, the arc-flash will do a nice impression of a bomb, with similar risks to personnel.

It is conceivable that China has devised a superconducting, DC EMALS system. If so, good for them. I don't see any actual advantages to what is currently on the Ford carrier. In a war environment, the KISS standard still applies. Fancy for fancy's sake didn't do the German's a lot of good in WW2 and it still won't today.

[steve2267]

That is a VERY NICE 2nd post. I too welcome you aboard!

[spazsinbad]

Thanks to 'zerion' on another thread posting about these events - the JPALS part reposted here because it is THE THING.

viewtopic.php?f=57&t=53429&p=383516&hilit=rough#p383516

USS Abraham Lincoln (CVN 72) Completes First F-35C Carrier Qualification
15 Dec 2017 Mass Communication Specialist Second Class Jessica Paulauskas, USS Abraham Lincoln (CVN 72) Public Affairs

"The Nimitz-class aircraft carrier USS Abraham Lincoln (CVN 72) successfully completed Fleet Replacement Squadron (FRS) Carrier Qualifications for the F-35C Lightning II program, carrier qualifying the first nine fleet aviators in the new aircraft, while underway Dec. 7-11.

Along with Abraham Lincoln, the "Rough Raiders" of Strike Fighter Squadron (VFA) 125, the "Grim Reapers" of VFA-101, and VX-9 accomplished many first steps including... use of the Joint Precision Approach and Landing System (JPALS) in an operational setting.

"Thanks to the tireless work from the VFA-125, VFA-101, VX-9, CVN72, and the Lockheed Team this detachment was able to successfully complete numerous milestones that will set the foundation for the future 5th generation employment of the F-35C into the Carrier Air Wing," said Cmdr. Scott Hulett, VFA-125 executive officer....

...Abraham Lincoln operated in inclement weather during portion of the qualification process, which gave the squadrons varying condition to test the new landing system, JPALS. The all-weather system works with the ship's navigation system to provide accurate and reliable guidance for the aircraft. Prior to this underway, F-35Cs only used JPALS for developmental testing...."

Photo: "ATLANTIC OCEAN (Dec. 8, 2017) Sailors prepare to launch an F-35C Lightning II assigned to the "Rough Raiders" of Strike Fighter Squadron (VFA) 125 during flight operations aboard the Nimitz-class aircraft carrier USS Abraham Lincoln (CVN 72). (U.S. Navy photo by Mass Communication Specialist 1st Class Josue Escobosa/Released)" https://www.navyrecognition.com/images/ ... tion_1.JPG

Source: https://www.navyrecognition.com/index.p ... ation.html

[spazsinbad]

More EMALS cats than anyone needs to see in a lifetime aboard FORD - sad that EMALS does not work - but hey it might.

[steve2267]

AAGS seemed to work just fine in the first video, when the aviators cared to lower their tailhook . What is the purpose of bouncing off the deck? Just for the fun of it? Or does a training or qualification evolution require a certain number of approaches and touch-n-goes just enables getting in the required number of approaches?

[neptune]

More EMALS cats than anyone needs to see in a lifetime aboard FORD - sad that EMALS does not work - but hey it might....

...in the spirit of the season, LEDs for the house decorations, auto decorations, drone decorations; the EMALS should add LEDs to the shuttle coils to provide visual indication of the progress along the chute during a/c launch, maybe alternating Red, White and Blue!

...perhaps similar with the AAG!

[spazsinbad]

AAGS seemed to work just fine in the first video, when the aviators cared to lower their tailhook. What is the purpose of bouncing off the deck? Just for the fun of it? Or does a training or qualification evolution require a certain number of approaches and touch-n-goes just enables getting in the required number of approaches?

You do not need to have that attitude - ignorance is just that - a simple question would suffice. Depending on situation with LSOs & Pilots - for example new deck landers require two rollers/touch and goes hook up before putting hook down for first arrest. At least once this has been explained on other NavAv threads. Also experienced pilots 'not having deck landed for awhile / deck landing for the first time on a new carrier' carry out at least one roller but probably two, to get a look at the deck and new perhaps line up situations not seen before. Also LSOs need to adjust their 'eyes' to the carrier from their previous FCLP 'eyes' - practice in case of bolters LSOs/Pilots need to get that power on quick smart.

[steve2267]

Sorry... no attitude intended or implied. I shoulda added the smiley. Corrected.

I was surprised at the number of bolters at first. Because with, errr their magical carpet (strikeout Delta Flight Path), and/or all that technological flightpath geewhizzery the F/A-18 Super Duper possesses... I was surprised they woulda been missing the arrester gear, and on such a beyoootiful day with apparently calm seas. Then I looked again and seen no tailhook lowered. Hence my non-smiley enquirey.

ETA: Fixed carpetbagging of DFP

[spazsinbad]

The last word in the title of the first long video above is 'Testing' so that is in play also. Yes a bolter is not a roller. And Super Hornets have MAGIC CARPET. The F-35C has DELTA FLIGHT PATH (also 'MC' called something different now 'PLM'?).

viewtopic.php?f=22&t=53617&p=380932&hilit=magic+carpet#p380932

PLM = Precision Landing Modes name change found: http://navalaviationnews.navylive.dodli ... 17_web.pdf
&
http://foxtrotalpha.jalopnik.com/magic- ... 1793618342
&
viewtopic.php?f=57&t=52238&p=353004&hilit=precision#p353004

[mas]

Nice videos. I know it's called the Super Hornet but its size and lines remind me more of the original Tomcat than the original Hornet, similar power too. You kind of forget how bigger they made it until reminded.

[spazsinbad]

I like the look on the face of the chap with the spray bottle: http://static.atimes.com/uploads/2018/0 ... tapult.jpg at http://hrana.org/news/2018/01/third-car ... catapults/

"The new EMALS electromagnetic system on USS Ford. Photo: US Navy" [BOLLOCKS BUDDY!]

Looks like a STEAM catapult to me - I'll look around.... Here is the land EMALS open [from Naval Aviation News]:

http://navalaviationnews.navylive.dodli ... ture2a.jpg

[SpudmanWP]

This is what it looks like.



Here is an EMALS module being lowered into place.



According to this url, those photos are of the old steam cat being removed.

http://www.migflug.com/jetflights/the-a ... erior.html