The ring master was one of the most popular U-Control models of the 50s and 60s. Most of us had one as our second plane in my area. It used about a .15 to a .19 engine. One new in the box/kit would have some collector value but there are plans still available so anyone wanting one can still build the plane, there isn't a lot to them. To find an original is rare these days but they don't have a lot of value. Outstanding little stunt plane though and brings back a lot of memories. At one of the RC swap meets you could get a couple bucks out of it but used or broken planes don't bring in a lot of money.