Re: Railgun Research: Barrrel Design or Power Supply

From: Gregory L. Hansen (glhansen_at_steel.ucs.indiana.edu)
Date: 02/24/05 

To: sci-military-moderated@moderators.isc.org
Date: Thu, 24 Feb 2005 00:37:39 +0000 (UTC)

In article <3828lnF5a53loU1@individual.net>,
Dirk Bruere at Neopax <dirk@neopax.com> wrote:
>Gregory L. Hansen wrote:
>
>> In article <37uo06F5gclkrU1@individual.net>,
>> Dirk Bruere at Neopax <dirk@neopax.com> wrote:
>>
>>>Gregory L. Hansen wrote:
>>>
>>>
>>>>In article <1108426538.282746.89420@f14g2000cwb.googlegroups.com>,
>>>>Picti <amcneish@swbell.net> wrote:
>>>>
>>>>
>>>>>Dan,
>>>>> I don't know about that. Are not the APDS and APDSFS projectiles
>>>>>fired by battle tank main armaments examples of kinetic energy
>>>>>pentrators that use speed to lance through armor?
>>>>>
>>>>
>>>>
>>>>The 120 mm cartridge has a 4 kg penetrator fired at 1740 m/s while the
>>>>last I've read on rail guns has a 1.6 kg dart fired at around 2300 m/s.
>>>>The math:
>>>>
>>>> (4*1740^2)/(1.6*2300^2) = 1.4
>>>>
>>>>They actually compare better than I'd expected, although the railguns
>>>>still need some development before they can match the energy delivered by
>>>>the 120 mm gun, not to mention the service life.
>>>
>>>I suspect that it is a dead end as far as tank armament is concerned.
>>>The future (as always) is smart missiles, either HE or KE kills (eg LOSAT).
>>
>>
>> Smart missiles are considerably more expensive, and for what benefit? The
>> Abrams, and other comparable tanks, are shooting quickly and accurately at
>> long ranges, and a HEAT warhead just doesn't penetrate modern armor the
>> way a slug of tungsten or depleted uranium going 2 km/s does. If they
>> weren't hitting their targets, that would be something to think about.
>> But they're hitting their targets.
>
>Providing their targets are pretty much line of sight. A missile can hunt tanks
>that are below the line of vision, or hiding behind something.

The LOSAT is line of sight, that's what LOS means. Dragons and TOWs are
line of sight in that the operator needs to keep the cross-hair on the
target; if suppressive fire forces him to take cover the shot is ruined.
Some missiles like the Hellfire can home in on a laser spot placed on the
target by a separate designator, e.g. an infantryman can paint a target
while the missile is fired from behind a hill.

For the most part, seekers are still in the future. I think the
Copperhead was an artillery shell that could home in on certain IR
frequencies reflected by metal objects. But if it's known something like
that is being used in significant quantities, it's not hard to imagine
ways to defeat it.

>
>> The KEW-A1 120mm shell is 43 pounds and around 30 inches long, the LOSAT
>> is 174 pounds and 113 inches long. It's four times bigger and four times
>> heavier. It's meant to provide an early anti-armor capability before the
>> MBTs are brought in.
>>
>> One of the attractions of rail guns is that the projectiles are smaller
>> and they don't have the powder charge, which is hoped to simplify
>> logistics and improve autoloading systems.
>
>At the cost of vastly increased complexity. The energy still has to come from
>somewhere, and in addition has to be converted into electricity first. It all
>sounds as plausible as the nuclear powered tank. No doubt that too would
>save on
>fuel logistics etc.

As the line goes from the US Army's All-Electric Vehicle Program, the
energy would come from the same diesel powerplant that's running the rest
of the vehicle. You know about gasoline-electric hybrid automobiles that
have hit the market recently. Some folks think it would be cool to make
diesel-electric hybrid main battle tanks. One thing they like about it is
the ability to run silently on batteries for short distances.

I don't know how feasible that electric stuff is in the end. But I do
think it's very unlikely that tank guns will be replaced wholesale by
missiles that are four times larger, four times heavier, and I don't know
how much more expensive but if they have sensors and electronics in them
at all they'll be a lot more expensive. A hummer with a TOW might be able
to kill one tank, if it's not firing on modern armor. But that doesn't
mean it can replace a tank. 

-- 
"'No user-serviceable parts inside.'  I'll be the judge of that!"

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