Wasn't the procedure implemented in the early sixties, after a DC4 departed RW30 straight ahead, with a cloud base of around 800'. At about 1500' in IMC, they had a run away propellor. My memory is getting a bit dim these days, but I understand that the Captain made and immediate right turn and descended o get visual downwind for RW30. When the estimated return path was plotted. it showed that the aircraft came very, very close to Mt Lord. Hence the design of the SID for low performance piston engine airline aircraft such as the DC3, DC4, DC6 and the turbine Viscount and F27. The Electra was about the only aircraft that could accept departure on runway heading. The procedure was also flown by DC9 jets and the early 727's, with an exemption in later years for the later versions of the 72.
Nothing nicer than being in the bowels of a full DC9 at night departing RW30. The turn occurred straight after rotate and used to gain the full attention of the punters on board!!!