This is one I had never encounterd before. During WWII the British employed an Austrian Helicopter designer named Raoul Hafner. From 1940 to about 1944 they experiemented with using the autorotational properties of an unpowered gyro rotor to drop people and equipment to the grounds more safely and accurately than a parachute could. This lead to some interesting test concepts!
For example the RotaJeep or Roatabuggy was a jeep that could be dropped from an aircraft and flown to the ground and then later towed home through the sky by a plane!
The Rotachute concept even encompassed a RotaTank though I find no evidence that the tank was actually tested.
From my point of view. . .
This concept would make for excellent zepplin escape/life craft! Imagine a rotachute big enough to carry 10 passengers or so!
I can also imagine this being used to silently insert operatives or drop smuggle in loads of contraband goods!
Unpowered and super cheap to the point of being disposable! Picture a RotaJeep dropping from a zepplin and then landing on a dark road at night, the roads only illumination being from the headlights of the waiting bootleggers cars. The Jeep lands, folds up it's tail rotors and quickly unloads it's hooch into the waiting vehicles then leisurely drives (without any damning evidence) to an airport to await pickup or a tow home.
*Laughing* Good fun!