Hellfire RX 9 missile

[David Johnston2]

So the United States has a cruise missile that has no explosive warhead but popout blades. How much damage that does that do?

[Varyon]

Assuming the mock-up in the online NYPost article I found is to scale, I think the fins increase the diameter by 5-7x. According to Wikipedia, the diameter of a typical hellfire missile is around 7 inches. So, we're basically looking at a diameter of 35 to 49 inches; I'd be comfortable saying this is essentially a mobile 1-hex area effect that deals cutting damage to anything it encounters.

As for how much damage, a hellfire missile apparently weighs around 100 lb and has a top speed around 500 mph, or Move 250. We'll say HP 20 and Move 200, for 40d of collision damage. However, because it is a sharp surface, this gets cut in half and becomes cutting, for 20d cut. Given the purpose of the weapon, I'd imagine the blades are really just there to increase the effective diameter, increasing the probability of actually hitting the target (in GURPS terms, you can aim at a Hex, and the target has to do a Dodge and Drop rather than just a Dodge to get out of the way); they are likely thin, and therefore sharp, to limit how much drag they produce, more than because this has a greater effect on-target (a blunt rod attached to a 100 lb missile going above Mach 1 is going to kill you just as dead as a razor-sharp blade; humorously, in GURPS, a blunt rod is actually better in such a situation, as it would average 140 HP Injury on an unarmored target - as opposed to the 105 HP Injury of the blades - and also lose less Injury from armor - only 1 HP per DR, rather than 1.5 HP per DR against steel armor, or 0.25 HP per maxDR rather than 1.5 HP per maxDR against kevlar or similar).

[mlangsdorf]

Eyeballing from the extremely limited wikipedia write-up, it's a roughly 20 lb payload set up as something mechanically similar to Beehive (HT 173), but only using 6 projectiles.

Looking through High-Tech, the Sidewinder (HT 152) has a similar payload weight for a annular blast fragmentation (ABF, HT 174) warhead. Looking at the description of beehive and ABF, they're both mechanically similar to shrapnel (HT 172-173) so I'm going to guess that we can derive stats for one weapon from the other.

The Sidewinder is a 1x194 attack, for NP = 200 and NS = 0.071 (see HT 172). The Hellfire RX9 wuold be a 1x6 attack, for NP = 6 and NS = 0.38. The Hellfire's blades should do about 5x (well, 5.35x) the damage of the Sidewinder's fragments, which is 6d+1.

So you end up with an attack line something like:
Hellfire RX9 Cu 6dx5 1x6
along with the normal weight, range, Acc, and cost of a Hellfire, which I don't feel like calculating.

Getting hit by one of the blades does around 105 points of cutting damage, instantly killing any normal human in any armor with less than DR 60 and destroying the body of an unarmored human with HP 15 or less. Seems kind of overkill, but with only 6 attacks, it does limit collateral damage somewhat.

[mlangsdorf]

Originally Posted by Varyon

As for how much damage, a hellfire missile apparently weighs around 100 lb and has a top speed around 500 mph, or Move 250.

Wikipedia says a top speed of 1000 mph or Move 500. HP 20 at move 500 is 100d of damage, halved for cutting, or 6dx8. Again, seems like overkill, but very targeted overkill.

[Curmudgeon]

Plugging the values into GURPS Vehicles formula for KE missiles, the 180mm diameter without blades extended and the Hellfire's top speed of Mach 1.3 (995 mph) and not treating it as a Beehive round, gives 83,880d damage, treating it as a Beehive round reduces the damage to 20,970d.

With the blades extended (blades are given as increasing the diameter by 1 m), the damage is 549,880 d, or 147,645d as a Beehive round. Damage is impaling as a Beehive and crushing otherwise.

While these damage values are for 3e, the best response for use against a human target is "too great to bother rolling for, there isn't enough left for even resurrection to be an option."

[Varyon]

Originally Posted by mlangsdorf

Wikipedia says a top speed of 1000 mph or Move 500. HP 20 at move 500 is 100d of damage, halved for cutting, or 6dx8. Again, seems like overkill, but very targeted overkill.

Whoops, I saw 995 mph, rounded it up to 1000, dropped that to Move 500 in my head, then thought the 500 was the mph and reduced it again. Regardless, yeah, this is something that's going to dice up anyone it encounters.

[David Johnston2]

Originally Posted by mlangsdorf

Wikipedia says a top speed of 1000 mph or Move 500. HP 20 at move 500 is 100d of damage, halved for cutting, or 6dx8. Again, seems like overkill, but very targeted overkill.

Well I was considering the potential of such a weapon for neutralizing thousand point supers.

[Anthony]

Originally Posted by David Johnston2

Well I was considering the potential of such a weapon for neutralizing thousand point supers.

Most thousand point supers are going to be pretty unhappy about hits from weapons far smaller than a hellfire missile, it's just pretty hard to actually bring them to bear (this is a problem in the real world as well; sure, we had a weapon to use, but it took twenty years to get a viable targeting solution).

[Varyon]

Originally Posted by David Johnston2

Well I was considering the potential of such a weapon for neutralizing thousand point supers.

Depends on how they've spent their points. Enough general-purpose DR to negate an average-damage hit, assuming we go with 50d cut (average damage 175), would cost [875], leaving little room for the character to do much else (assuming by "thousand point supers" you mean "supers worth [1000]" rather than "supers worth several thousands of points), so probably not an issue against those. Simply getting it down to a survivable level - say around 15 HP Injury - would only save 50 points. Of course, if that level of survivable is sufficient, IT:DR will handle it much cheaper - a divisor of 20 will reduce average Injury to 13.125 HP, and for general-purpose IT:DR that costs [200]. Heck, spend half your point budget (so [500]) on general-purpose IT:DR and you wind up with a divisor of 500, which reduces this to a 1 HP scratch (and only because of rounding - average Injury would be 0.525 HP without accounting for rounding).

EDIT: Of course, using Limited Defenses will get the costs down. Physical Only -20% reduces the above to [700], [160], and [400], respectively, while Cutting Only -40% reduces the above to [525], [120], and [300], respectively.

[Willy]

From all what I could find about the topic, there were some news that this missile is also used to punch holes in targets to make way for other warheads.

In that case, I would say the blades are from a hardened material, not just the regular weapon grade steel or titan. Maybe we should treat this blades as fine or very fine quality, not that this is important for the target, dead is dead, and that thing would kill a blue whale.