Tuesday, December 17, 2013

One step closer to the Slammers

Also to battlefield aviation being all drones, because aircraft won't survive for long.

Because if you can shoot down rockets, missiles and mortar shells, you can hit an aircraft.


Marja said...

Yep. No heroic Luke Skywalkers hitting the exhaust port in the future, or dogfights between ours and the alien invader fighters in the canyons of western USA. The thought kind of ruins half of the SF movies I have liked, even if I have always figured fighter jocks might be one group who realistically speaking did not really belong in science fiction stories. Even if there will be something in the air in the future they wont be piloted by humans. Or aliens. :(

markm said...

That depends on whether the beam actually has the energy to take down a fighter, which unlike the current generation of drones was built to take a little punishment. That huge truck mounted laser system currently has a power output of 10KW, which is less than an M-16:

5.56x45mm cartridge muzzle energy ~ 1700J (specs from Wikipedia).
M-16 rate of fire: ~600 rounds per minute or 10 per second.
Power = 1700J* 10/second = 17 KW

They are hoping to increase the power to 50KW and then 100KW. At 50KW, it's a bit more powerful than an M14. 100KW finally gets up into the range of weapons that can't be carried by one man. For the lowest rate of fire (485/minute) for the M2 .50 Browning, I get just over 100KW. They aren't even contemplating anything that will compete with a gatling.

But you can carry an M2 in a jeep, and you can fire continuously until the barrel is destroyed by heat. The laser requires that enormous truck, or eventually a heavy tank chassis - so at least it won't be vulnerable to a sniper with a bolt action rifle. And that's not going to get much better until someone invents a better way to provide 500KW or more of portable _electric_ power than an 800+ horsepower engine and generator. Quite simply, the best power/weight ratios come in the form or mechanical energy from rapid chemical reactions: cordite burning in an enclosed space, rockets, and bombs. But you can't hitch these to a generator; their advantage is that the released energy is coupled _directly_ to the output. (This has nothing to do with the energy density of the fuel; gasoline is superior to explosives by this measure.)

The laser does have one advantage - it's much better at hitting a fast moving target under ideal conditions. If there's fog or smoke, it's just a bright light instead of a concentrated beam that can burn through metal...

The real threat isn't lasers, it's radar-guided rapid-fire guns, e.g. the Phalanx system. That doesn't eliminate airplanes, but it requires them to stay out of range and use missiles or other stand-off weapons. I suspect that ultimately manned military aircraft will just be airliners modified to tote the drones to near the combat theater.

markm said...

Secondly, it's not very difficult to harden weapons against lasers. The first defense is simply a reflective surface. The second is a layer of heat-resistant material. If lasers are deployed to battlefields, you'll soon see even mortar shells hardened against them. It takes much less to to harden a target against lasers than against gunfire.