Just a bit of info from 1968.
Due to the higher speed and newness of the Cobra (they went to Nam in Sep 67,) Several Cobras were pranged and crews killed due to target fixation and ground impact because they started their pull outs too low. To help relieve the problem, the Army dictated that cobras would fly no lower than 1500 above the ground in their attacks and no closer than 700 meters slant range from the target. That lasted quite along time till crews became proficient in the new machine. It had nothing to do with courage. A pilot risked an FEB or court martial if he violated the rule and pranged his bird. I was a cobra pilot in 1970 and also an instructor in them later and remember the restriction. It went away as the war progressed. but Blame the training, tactics and the commanders .. not the "pink Pusssies" it warn't their fault-))
BT