EMALS, linear motor carrier jet launch system

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cycleops612
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EMALS, linear motor carrier jet launch system

Post by cycleops612 » Oct 15, 2016 2:28 am

https://en.wikipedia.org/wiki/Electroma ... nch_System

45 tonnes to 240kph on a carrier deck.

U would think it a boon for commercial jets eventually

u would think remoter, hi altitude airports (plateaus?) on HSRail to population centers would help save fuel too - denver is very high as i recall. Most are now at sea level~. Saves planes climbing/descending maybe 4000m.

The piece doesnt add up tho. If all they have to do is spin up flywheels with the power available (a nuclear carrier would have over a million HP from the reactors and turbines), less electric power on the nimitz class e.g. just means slower launch intervals, or modest upgrades to power gen capacity.

Further, "using the rotors of four disk alternators; the system then releases that energy (up to 484 MJ) in 2–3 seconds.[4] Each rotor delivers up to 121 MJ (34 kWh) from 6400 rpm (approximately one gasoline gallon equivalent) and can be recharged within 45 seconds of a launch" 484MJ TOTAL launch power (132kw) is not a lot of power. a corolla is about 80kw, let alone a turbine connected to a jet motor, which one assumes they have lying around (& fuel), & dont weigh much .

A know it all friend fell about laughing when i postulated flywheels as huge poor mans "capacitors" - v fast charge storage - yet here we see exactly that, perhaps heavyish in conventional perceptions, but that depends how fast u spin the mass. F1 motors and hard drives do 20k rpm, so 6400 rpm sounds modest.

Note the even number of rotors. I suspect they are counter rotating pairs to counteract any torque effect/vibrations from the spinning mass.

Westinghouse were suggesting it to the navy in 1946 - cool company.

The steam method of launch byw relies on "mats" which lift as the hook passes & fall to seal of the steam it after it has passed. not efficient as we see here, and from the escaping steam.

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Re: EMALS, linear motor carrier jet launch system

Post by Foob » Oct 25, 2016 10:36 am

Of course, launching using flight engines has the advantage that you know your engines are running well enough to sustain flight before leaving the ground.

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Re: EMALS, linear motor carrier jet launch system

Post by cycleops612 » Oct 25, 2016 11:46 am

I am sure the navy(s) dont like losing planes over the front either. not sayin u r wrong, but it may even be safer at times - can glide to a landing.

eg, do they lose more of identical fighters on takeoffs from decks or runways? carrier planes use both of course.

Bears investigating, but not insoluble?

Finite jet fuel IS insoluble, as is airport noise.

This is critical for navies now. It means less vulnerable fuel supply logistics to the "battle front" (launch assist power is from the ~limitless nuclear reactor of course), and greater strike payload/range.

a benefit they stress, is less stress on planes than ye old steam catapaults. its very gradually and precisely applied force. i.e., whereas carrier planes needed big mods in the past, its less so now.

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Re: EMALS, linear motor carrier jet launch system

Post by Punx0r » Oct 26, 2016 2:17 am

I don't think the launch and catcher system on a carrier is used for any reason other than its the only way to take-off and land in such a short space. I would be surprised if there was any desire to use a much scaled up system at a commercial airport. Definitely advantages over steam on a carrier, though.
cycleops612 wrote:Further, "using the rotors of four disk alternators; the system then releases that energy (up to 484 MJ) in 2–3 seconds.[4] Each rotor delivers up to 121 MJ (34 kWh) from 6400 rpm (approximately one gasoline gallon equivalent) and can be recharged within 45 seconds of a launch" 484MJ TOTAL launch power (132kw) is not a lot of power. a corolla is about 80kw, let alone a turbine connected to a jet motor, which one assumes they have lying around (& fuel), & dont weigh much .

Where did you get 132kW from? I think you're mixing up kW and kWh. A joule is one watt-second, so 484MJ delivered in 3 seconds is 161MW (161,000kW). A lot!

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Re: EMALS, linear motor carrier jet launch system

Post by cycleops612 » Nov 25, 2016 11:15 am

I now hear the us navy is having big (secret natch) problems getting it to work.

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Re: EMALS, linear motor carrier jet launch system

Post by spinningmagnets » Nov 25, 2016 11:50 am

I know this sounds cynical, but this could also be a sneaky way of getting funding for rail gun research.

We still don't have a moon base, so...why did we go to the moon? I believe it brought the entire US public and congress on board to fund a program that also resulted in a lot of advanced ballistic missile research raw data. To be clear, there was funding that was knowingly applied specifically for ballistic missiles. I just believe the moon race shifted a lot of corollary tech to a nice program, so the missile-specific funds could be much more effective and broadly applied.

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Re: EMALS, linear motor carrier jet launch system

Post by cycleops612 » Nov 25, 2016 3:32 pm

spinningmagnets wrote:I know this sounds cynical, but this could also be a sneaky way of getting funding for rail gun research.

We still don't have a moon base, so...why did we go to the moon? I believe it brought the entire US public and congress on board to fund a program that also resulted in a lot of advanced ballistic missile research raw data. To be clear, there was funding that was knowingly applied specifically for ballistic missiles. I just believe the moon race shifted a lot of corollary tech to a nice program, so the missile-specific funds could be much more effective and broadly applied.
What, now they want to fire rails at folks? :)

Well, there is an argument that air power is just a variant of artillery.

But yeah, in my dotage I am of the view that even the most benign seeming govts. merely provide a semblance of legitimacy to the corrupt elites, which in turn control the "regime".

War e.g is more about "public morale" than soldiers lives. Absurd campaigns which sound good. McArthur retaking the philippines e.g. instead of the sensible nimitz policy of island hopping & isolating. Sieges e.g are cost effective, but make drawn out, dull propaganda.

Even legit wealth has to be protected, and that means political influence. The british aristocracy had a scion inherit all (primogeniture), one son for the army and one for the church/politics/court. The family had a finger in each traditional pie, inside info and protection against social upheaval.

We digress. In theory and practice we know it works (BLDC/mag lev etc.).

To steam launch uses existing boilers. The huge power for electric launch requires new extra power infrastructure on the ship, and this seems harder than expected.

They alone seem keen. Others favour ramped flight decks, which the US seems not to?

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