The Hunter UAV lost out to the Predator in the 1990s competition for a battlefield UAV. But the army kept in storage the ones it had, and put them back in action in time for the 1999 Kosovo operation. The 1600 pound Hunter can only carry 200 pounds of sensors and weapons. So that ruled out the Hellfire. But Hunter could carry two 44 pound Viper Strikes. Helicopter pilots are selected and trained to operate the armed Hunters. This is all still experimental, with only six Hunter UAVs modified to drop Viper Strike, and only 78 Viper Strike weapons have been modified to be dropped. There is only one company of Hunter UAVs in Iraq, and not all of them are modified to handle Viper Strike. There is also a lot less enemy activity in Iraq lately, so it may be a while before a Viper Strike equipped Hunter comes across a target worth hitting.
The army is also modifying the larger Ignat UAV to fire hundred pound Hellfire missiles, but this system wont be available until later this year. A few years down the road, the army will introduce a new UAV to replace Hunter, one that will be able to carry Viper Strike or Hellfire. Theres also a new, lighter (by about ten pounds) Viper Strike in development.
After several years of work, the U.S. Army has got some armed UAVs operating in Iraq. Using a cancelled UAV design (the Hunter) and a cancelled Cold War anti-tank weapon (the Viper Strike), the army has created a useful precision weapon for urban warfare. The 44 pound Viper was designed to be dropped from the air (delivered via a MLRS rocket, or a bomb like cargo container carried by a bomber), seek out armored vehicles below, and use its four pound warhead to penetrate the thinner top armor. The UAV dropped Viper is laser guided, and accurate enough to hit a pickup truck parked in an alley. The army was pleased to discover that the four pound Viper warhead could wreck a truck or automobile, and do little damage to anyone, or anything, next to the vehicle.
All this is causing heartburn in the air force, which is, according to an agreement hammered out in the 1950s, supposed to supply all fixed wing aircraft support for the army, and control all of those aircraft. For the moment, the army is basically daring the air force to try and take away the UAVs that army combat troops are using. The army is doing nearly all the fighting these days, and the air force is leery of bad PR by appearing petty in wartime.