High Drink
This is dated, but may be of interest to both the long line pilots and the H-2/H-3/H-60 dipping community.
In the late 60's early 70's the DOD folks came up with a requirement to be able to keep an H-3 in a hover at 10,000 ft for extended periods. Hence the design included a 10,000 ft long flexible refueling hose. So the idea was to lift off, haul the hose to 10,000', engage the " Hover " coupler in the AFCS, and sit there for 8-10 hrs, all the while taking on fuel from below as needed. It didn't stop with the concept. The hardware was built and flight tested, as I recall, at the Augusta Ga Airport. Pilot was Kurt Cannon. You all can imagine the challenges. I do not recall why it did not go forward, but can think of a good number of reasons.