The U.S. Army is testing two micro-UAVs, to complement, or even replace, the Raven model that is already in use. One of the new UAVs, the Wasp III, is already in use by the U.S. Air Force and Marine Corps. This 545 gram (one pound), battery powered aircraft has a 74 cm (29 inch) wing span and can stay in the air for 45 minutes at a time. It uses forward and side looking cameras and can fly up to five kilometers from the operator. Max altitude is 170 meters. The Wasp III uses the same ground controller as the 4.4 pound Raven. The same firm makes both Raven and Wasp (and several other small UAVs.) The air force buys small UAVs for use by its security troops, or airmen who are helping the army out with support jobs in Iraq.
The army has bought thousands of the 2 kg (4.4 pound) Raven, but it is mostly used for convoy and base security, and less so by troops in the field. The infantry wanted an even smaller UAV than the Raven. Noting the marine use of Wasp, they are trying it out. One reason for not trying the Wasp earlier is that the army, unlike the marines, has a larger force of bigger UAVs (like the Shadow and Gray Eagle) to provide commanders on the ground with a picture of what's happening.
But the army is trying to see which size micro-UAV would be the most effective. Thus the field tests for the larger Puma, a 4.5 kg (10 pound) UAV with a 2.6 meter (8.5 feet) wingspan and a range of 15 kilometers. Top speed is 100 kilometers an hour, and cruising speed is 25-50 kilometers an hour. Max altitude is 3,800 meters (12,500 feet). Puma has a better vidcam, which provides steadier pictures. Puma has been around for a decade, but never got purchased in large quantities by anyone. The latest model uses much proven tech from the Raven (both UAVs are made by the same company).
In the last decade, troops (who operate them) and commanders (who make decisions based on what the UAV reveals) have acquired lots of experience with UAVs, especially the smallest ones (Wasp, Raven, Puma). The army would like to standardize on one micro-UAV, but also has to deal with the possibility of have more than one model available, because one size may not be a good fit for all combat situations.