Hovering in History looks at the US Army’s many attempts to puts its soldiers into the sky, inclusing the Williams WASP:
At around the same time, Bell Aerosystems was developing a series of rocket and jet packs for military use. The army lost interest when it found that maximum practical flight time was less than thirty seconds, but the small kerosene jets used in these jet packs were later employed in other configurations. This engine would become the basis for Williams Research Corporation’s WASP (Williams Aerial Survey Platform). Test pilots would come to give it the nickname “Flying Pulpit”.The WASP, later named the X-Jet, was the result of fifteen years of development. It looked a bit like a flying garbage can, with the pilot standing on the fuel tank and a 600-pound turbofan engine mounted in front of him. Performance of the WASP was impressive, with a speed of 60 mph and a service ceiling of 10,000 feet. Maximum flight time was just over 30 minutes. The craft was listed in Jane’s All the World’s Aircraft as late as the 1985 edition but once again the army, which had financed its development, lost interest.