I had two in the mid-late 80's, first one had an Enya 45CX and a later one had a YS 45 w/pipe; both flew great. I didn't bother with retracts in either of them, I had 60 size pattern planes for that and the Mattlas' were just for fun. I recall buying the first kit in around '84 and I'm sure I had seen them advertised for some years earlier. MK also kitted a 20 sized Mattlas, and I had two of those also

Beautiful kits, very enjoyable to build. Wish MK were still available and afordable!