Helicopter Questions

Hello,



I was reading that during the Vietnam War two helicopters were downed by
MiGs, one was a HB-53B which was downed by a MiG-21 on 28 Jan 1970, but I
can't find much info about the other. All I found so far was a "UH-1 during
1971" on the ACIG-site. Has somebody here more info?



Another question I have is about those seven helicopters downed by SAMs in
1972. I know that at least four of them were AH-1 Cobras, which were shoot
down during May and June. Did somebody know more about the other three?



Thanks!



MCN