I didn't read your link. But I have read a few books about Cobra pilots in Vietnam. A few things were a common theme in each of the books. The pilots hated the blue-tinted canopies because it ruined night vision. The fact that the gunner and pilot canopies opened on different sides was also universally hated. And the Huey Cobras developed a strange vibration that eventually lead to disentegration of the the Cobras. As far as I know, the cause was never discovered.