Battlefield Air Interdiction (BAI) remains one of the tasks carried out by most modern airforces. The targets in these cases are classed as either soft (personnel, non-armoured vehicles, etc.) or hard (APCs, tanks, etc.). In general the weapon most often selected to attack such targets have been cluster bombs or specially designed dispensor systems (such as JP233) which release dozens of submunitions over a wide area (hence the term area denial). The problem with both of these weapons (and particularly the later) was the need to fly at low altitude over the target area itself. This of course leaves the aircraft open to anti-aircraft artillery, shoulder launched anti-aircraft missiles and the like. The obvious solution to this problem is to attack the targets from a safe distance.
The are basically two ways to enable such a stand-off to be achieved. A powered precision system could be utilised against a specific target (or targets), examples of this solution could include; Brimstone, TAURUS or Storm Shadow. However while these are generally complex and hence expensive (particularly TAURUS and Storm Shadow). The alternative is to continue using submunitions but launch them from a vehicle which in turn is launched by the aircraft. The DWS-39 is an example of such an unpowered glide dispensor
The name DWS-39 is actually somewhat misleading, the original designation was DWS-24 or Dispensor Wweapon System 24 tubes. This refered to the total number of dispensor tubes contained with the vehicle. However the primary platform for initial deployment of the system was to be the SAAB/BAE Systems JAS-39 Gripen and so DWS-24 became DWS-39 (refering to the Gripen). The Swedish Air Force have actually named the weapon Mjölner after Thor's Warhammer.
The system comprises of basically four major sections; nosecone, electronics, dispensor system and tailcone. The electronics package contains the INS and Radar Altimeter which provide guidance information and enable release of the submunitions at the given target location and altitude. The weapon utilises two mid-point fixed wings providing lift and four tail-cone mounted moveable fins. The dispensor system is relatively simple comprising of 24 tubes running perpendicular to the major axis of the weapon, each tube contains 3 charges. The charges themselves can be one of two types; MJ1 a 4kg (~9lb) air burst explosive and MJ2 a 18kg (~40lb) anti-armour charge. The system can utilise either a specific type or mixture of both MJ1 and MJ2. The submunitions are chute retarded upon release creating a coverage area approximately 250 metres wide and between 300 to 400 metres long.
At the present time DWS-39 is in use by the Swedish Air Force aboard the JAS-39 Gripen. It is also one of the weapons to be cleared for future carriage on the Eurofighter Typhoon. DWS-39 was also the basis for the TAURUS precision attack system, most noticeable similarility being the tailcone fin arrangement. In addition a powered version of DWS-39 has been proposed, designated D-7.
Much of this information was obtained from Urban Fredriksson's Missile Non-comparison Table site.
* : Note that all ranges quoted are based on mean figures from various data sources. Actual achievable range will depend on a great number of factors and may be no where near those quoted.