Originally posted by jappel:
Neat concept! Hmm, what's the weight breakdown for the LOSAT and launcher by component - i.e. X much for the penetrator, Y amount for propellant, etc.? If that kind of info is available or can be inferred from the available data, perhaps we can figure out how & when the weight can be reduced?
Also, while the missle weighs in at 110 pounds, how much does the launcher weigh? How much stress does it have to withstand?
Well, another source says 157 pounds for the LOSAT, but I think that inclueds the launcher. Amazingly, the LOSAT has 5x the KE of the 120mm gun on the M1A2! Holy tank killer batman! IIRC, that is an 8 MJ gun, so the LOSAT is something like 40MJ and a range of over 5km. The LOSAT travels around 5000fps
Now consider that the SCRAM jet recently tested ran at around mach 7 (about 7700 fps)
My weapon isn't so ambitious, but lets do some numbers.
If the 120mm gun generates 8MJ at 5000 fps, then the penetrator masses 7kilos. If we can get that same 7700fps we only need a 3 kilo penetrator for the same 8MJ. Now we get into a more grey area. If the LOSAT has about the same muzzle velocity as the tank gun, and 5x the energy, then the projectil must mass 5x more, or 35 kilos. Even if we take the higher weight figure, that works out to be about
80 pounds of rocket propellant (and as little as 33).
Doing some real SWAG, and assuming a linear relationship, if it takes 80 pounds of fuel to send a 35 kilo projectile at 5000fps for 5 km, then a 3 kilo projectile should take about 8 pounds. The Javelin ATGM weighs in at 50 pounds, including sight, So I arbitrarily set our KE missile at around 30 pounds. Let see how that 'feels'.
We aren't rocket scientists, so we add a fudge factor both for the higher velocity (7700fps) and becase we don't think it's a linear relationship.
Because this is a LOS, short range weapon without guidance (to keep it cheap) we set the maximum effective range at at 100- meters. We add a smple telescopic sight and aknowledge that it really is most effective at 500m and takes some skill to hit at the full range. Because it's a missile, and is ejected from the tube like a javeline, the launcher is nothing more than a disposable tube - probably with crude flip up sights. The telescopic sight is a separate item so that we can add FLIR or NV if needed.
Figure .5 kilo for the kicker charge, and maybe a kilo for the tube. That makes the rocket itself 12.5 kilos, with 3 kilos being the long rod pemetrator and around 9 kilos of rocket propellant (plus .5 kilos for fins and body).
From the above, that seems reasonable for a missile that only has to go 1000 meters before the motor burns out. The round is still dangerous out to several kilometers.
Assuming fairly high acceleration, the rocket (I'll call it SLOSAT - Short range Line OF Site AntiTank) will cover the 100m effective range in under a half second. Who needs guidance. Hitting a tank sized object at 1000 meters only requires an accuracy of about 10 MOA, which is about the same as hitting a 10 inch target at 100 yards, easily done with a rifle.
So, bearing in mind all the fudge factors, and infantryman can now carry a 30 pound disposable rocket that is the equivalent of a main battle tank 120mm cannon and can kill another MBT at 1000 meters with a flight time of under a half second.
And this weapon had a payload fuel ratio of 1/3, unlike the real LOSAT where its more like 1/1. If we back the fuel requirement down to only 1/2, we lose another 3 kilos, making the weapon more like 24 pounds or less.
Just to make it nice and neat, lets call it 22, or 10 kilos.
So, a 10 kilo disposable 8MJ tank gun. What's it cost? Well, we have a carbon fiber tube, plus the cost of the long rod penetrator and the rocket fuel and the rocket body. Zero electrolics and guidance to pay for. The optical sight is separate. The best optical sniper scopes from Leupold Stevens cost around $1200, or Cr400 using my conversion factor (explained previously). The tube is probably a Cr20 credit item in quantity, which leaves the rocket. At most, I see this as a Cr500 item.
So:
SLOSAT:
TL8, Length 1.3 meters, weight 10kilos, max effective range 1000 meters, cost Cr500 in quantity. The optical sight costs Cr400, or an electronic sight (with IR or LI) may be used instead.
The SLOSAT is an extremely simple, short range antitank rocket. In place of a more conventional HEAT warhead, it uses a kinetic energy penetrator. To operate the weapon, the user attaches the optical sight and removes the safety pin. He then acquires his target and presses the trigger. On firing, a small charge expels the rocket form the launch tube out to a safe distance from the firer where the main motor ignites. The high speed propellant quickly accelerates the rocket to 2350 m/s and the rocket continues in flight until it strikes it's target and acts like any conventional KE round.
The rocket is also equipped with simple flip out iron sights that are effective out to a range of 350 meters. And can be used in an emergency or if the optical sight is not available.
The flight time of the SLOSAT over its effective range is approximately 0.5 seconds, so compensating for target movement is largely unnecessary except at extreme ranges.
