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X-wing torpedo yield

Posted: 2004-01-18 03:04pm
by Ender
Cross posted from SW.com

Ok, since I already knew most of this from my work in the Navy, this only took me and google ~ 5 minutes.


I eyeball the proton torpedo at 50 cms tall and 50 cms wide at the base. Volume of a Cone is 1/3 height * area of base IIRC.

Now taking some assumptions from modern missiles: Fuel is 25% - 75% of the thing. Lets go with 75% to get a low end warhead yield. Now according to Star by Star, the things have ion engines on them. That means its going to use some kind of noble gas for fuel. Lets go with liquid argon: its inert, easy to store, etc. It has a density of 1.5x that of water. Lets assume the rest of the warhead has a density of water (~ what real missles have) That gives it a fuel mass of 36.8 kg and a total mass of ~45 kg.
Now according to I, Jedi proton torps have a flight time of 30 seconds, so it will eject ~1.2 kg per second.
According to here : http://www.stardestroyer.net/Empire/Tec ... pedo2.html they have an acceleration of 72,000 Gs. Since everyone knows Momentum = mass * velocity, and everyone knows the laws of motion, from that we can figure the exit velocit of the exhaust and its specific impulse (not relevent to the yield, but at 2,640,000 thats very impressive).

Now if we say that the sensors, power cell, casing, detonator, etc make up 20% of the remaining volume (not out of line, with the required microcircuirty and solid state electronics we see and the high energy density of power packs it is very reasonable) that gives us 5% for the fuel for the warhead itself. If we assume it it is thermonuclear in nature as indicated by the ROTJ novel, and assume only 50% efficiency (though modern warheads are more efficient, but we want low end), we can estimate its yeild.

Hydrogen fusion is typically what is meant, assuem the density of water, 5% of the total volume, and you get a mass of ~1.64 kg. Fusion releases 6.2*10^14 joules per kg. so multiply .5 * 6.2*10^14*1.6 = 5*10^14

or

120 kilotons

That is ~7.7 times greater then Hiroshima. And note that this si a focused explosion (so all the energy goes into the target) and the near miss barely scortched the paint on the Death Star. That is very tough armor. Now like I stressed, that is both low end and approximate and hinges on a number of assumptions. I'd feel better if I knew the volume:yield ratio for modern nukes and coud extrapolate from there, but what the hey.

Posted: 2004-01-19 03:16am
by Illuminatus Primus
I don't see why the 2 kiloton yield from the SWTC is wrong--these were whatever torpedoes were laying around in Rebel HQ, and for a very specific target, which wasn't designed to take any fire. Keep in mind missile weaponry much larger in AOTC not appearing to have kiloton-range damage, and likewise with TPM protons.

Posted: 2004-01-19 05:33am
by Sarevok
Since proton torpedoes were designed to hit heavily shielded capships their yield should be higher than the missiles seen in AOTC.

Posted: 2004-01-19 06:10am
by Kamakazie Sith
Yet, the proton torpedo blast caused internal explosions inside (unknown depth) the Death Star. Also, the X-Wings laser cannon seemed to penetrate the armor as well........

Posted: 2004-01-19 09:47am
by PainRack
Kamakazie Sith wrote:Yet, the proton torpedo blast caused internal explosions inside (unknown depth) the Death Star. Also, the X-Wings laser cannon seemed to penetrate the armor as well........
Where was this indicated?

Posted: 2004-01-19 09:54am
by Isolder74
PainRack wrote:
Kamakazie Sith wrote:Yet, the proton torpedo blast caused internal explosions inside (unknown depth) the Death Star. Also, the X-Wings laser cannon seemed to penetrate the armor as well........
Where was this indicated?
Whenever a X-Wing hit the Death Star they would show explosion and people being thrown around inside it. Whwn Red Leader's Torpedoes missed the Port they showed a much more violent version of this.

Posted: 2004-01-19 10:23am
by Illuminatus Primus
evilcat4000 wrote:Since proton torpedoes were designed to hit heavily shielded capships their yield should be higher than the missiles seen in AOTC.
Not all proton torpedoes. Given abysmal yields from the X-Wing series against ground targets, such micro-yield torps are necessary.

Posted: 2004-01-19 01:53pm
by Ender
Illuminatus Primus wrote:I don't see why the 2 kiloton yield from the SWTC is wrong
Aside from the ROTJ novel stating that missiles are thermonuclear and thus can't be less then 100 kt?
--these were whatever torpedoes were laying around in Rebel HQ, and for a very specific target, which wasn't designed to take any fire. Keep in mind missile weaponry much larger in AOTC not appearing to have kiloton-range damage,
The hailfire missiles? Most of that was the shaft holding the fins on. I'd put my money on those being fission and only beign a couple of tons.

The Slave 1 missile? I used basically the same method Saxton did, it shouldn't be any different, but scale it and tell me.

The LAAT missiles? We see them go off inside a target which is constructed of materials designed to disperse energy adn with a very high specific heat. Its no wonder.
and likewise with TPM protons.
One we see hit a shield, no gageing from there, the other was not likely armed.

Show the error in my math if you disagree IP.

Posted: 2004-01-19 02:00pm
by Illuminatus Primus
Ender wrote:
Illuminatus Primus wrote:I don't see why the 2 kiloton yield from the SWTC is wrong
Aside from the ROTJ novel stating that missiles are thermonuclear and thus can't be less then 100 kt?
The problem with it is not your math, but the baseline assumption here. The explosions around the Rebels were thermonuclear, so now, all missiles must be thermonuclear?

What about the Rogue Squadron novels' protons used on ground targets and some aircraft? Those cannot be in the hundreds of kilotons, or we'd see nuclear-style fireballs from excess heat bleed-off.

EDIT:

Did you scale for the two or three proton grenades by your formula for the explosion at Endor?

Posted: 2004-01-19 04:15pm
by Mad
Ender wrote:Aside from the ROTJ novel stating that missiles are thermonuclear and thus can't be less then 100 kt?
As I recall, RotJ stated that there was a "thermonuclear explosion," but never identified the source. It's pretty safe to assume that it was from an enemy weapon, but that weapon is unidentified. (We don't know if it was a proton torpedo, concussion missile, space bomb, or what.) To assume it applies to all missile weapons used in SW is a hasty generalization fallacy.

Posted: 2004-01-19 04:22pm
by Darth Garden Gnome
The original ICS says that the torpedoes used by Luke at Yavin were nuclear weapons, but not thermonuclear weapons, if that helps at all.