From: (WaltBJ)

FWIW I understand the initial idea for the 'Puff' series gunships was
the technique of servicing missionary stations in the Amazon with
Piper Super Cubs by flying in a tight circle while lowering a bucket
on a rope. Due to aero drag on the rope the bucket lagged behind and
pivoted on the polar axis of the circle and the ground people could
remove their mail, etc, and place their outgoing mail and requests in
the bucket which was then hauled back up. The rotation was slow enough
to be no problem, and then the curvature of the rope reminded someone
of the trajectory of a gun so - voila!

There was a photograph in National Geographic where a man in the Amazon is
reaching up towards a can. He had either just released it or was reaching for
it. The aircraft that had lowered it was off in the distance in the same
photograph.

The particular article was printed in the mid 1960s. 1967 or so if memory
serves.

It amazes me I can't remember 24 hours ago yet I can remember 35 years ago.

Dan, U. S. Air Force, retired