Did some trials at Boscombe with a 'Jungle Penetrator', intended for SAS recoveries out of high tree areas. The penetrator had three fold down arms as seats and the device was intended to be carried on the external load hook. Trial flight was on the Seaking and the line was 300' of 'nylon' rope. Once deployed, we did incremental speed runs over Salisbury Plain. From memory, the 'trail' angle was manageable until aboiut 40 knots, when the rope developed an uncontrollable sinusoidal rotation. The device, complete with rope, eventually went solo and returned to Mother Earth complete with trial dummies.! There were no further attempts while I was at D sqdn!!