It's all go in the world of hypervelocity railguns this week. Following Friday's 33-megajoule test shot carried out at a US Navy laboratory, it has also been announced that a different railgun known as "Blitzer" has recently carried out firings which suggest that it is almost combat ready.
The Blitzer comes to us courtesy of famous radical-tech company General Atomics, well known to Reg readers for its development of robot warplanes and electromagnetic mass-driver catapults for aircraft carriers among other things.
Now, in a statement which is dated 7 December (but which didn't appear on the firm's website until yesterday*) General Atomics would like to inform the world that the Blitzer was carrying out highly interesting and "tactically relevant" shoots back in September, actually, while the johnny-come-lately test job at Naval Surface Warfare Centre Dahlgren hadn't even got its boots on.
The Dahlgren railgun shot was a stepping stone towards projectiles launched at Mach 7+ with muzzle energies of 64 megajoules, which would (once weaponised) be able to fly 200 miles and hit their targets still going at Mach 5. Such long-range over the horizon bombardment is one of the stated aspirations of the US Navy's railgun project: but the test guns at Dahlgren are not weapons and their projectiles are not yet designed to fly through the air for any distance - they are focused on movement along the launching rails, from which they emerge at Mach 7.5.
Blitzer, however, is less about ultimate velocity and muzzle energy and more about proving a viable weapon. Its projectiles fly at only Mach 5: but they are much more advanced towards being actual munitions. In the Blitzer, the armature which moves along the rails and carries the driving current between them is merely a "sabot" which propels the actual projectile to launch speed and then falls off shortly after clearing the muzzle - rather as in the case of modern armour piercing tank ammo, which consists of a fin-stabilised penetrator dart which rides down the cannon barrel on discarding sabots.
According to the new GA statement:
This test demonstrated the integration and capabilities of a tactically relevant EM railgun launcher, pulsed power system, and projectile... The projectiles were launched by the Blitzer system at Mach 5 speed with acceleration levels exceeding 60,000 gee, and exhibited repeatable sabot separation and stable flight.
Blitzer will provide leap-ahead multi-mission capability in both naval and land-based applications. Using one weapons system, it provides defensive capability against a number of advanced air and surface threats and delivers strike capability against land- and sea-based targets. With demonstrated muzzle velocities greater than twice that of conventional gun systems, Blitzer provides a dramatic increase in standoff and lethality at lower cost, without the need for propellants or high explosives.
Apart from long-range bombardment of surface targets, another application seen for railguns is naval anti-aircraft work. At the moment, aircraft and ship-killing missiles present a terrible menace to naval forces: a sea-skimming aircraft or missile can appear above the horizon just twenty miles off. In the case of a supersonic missile, this leaves only a very short time for a warship to do anything about it.