plastic tip to an opener 22" long cylinder

The nylon shoe you show here appears to be a match for our 15-051. This might be what you want, but look it over and see if you agree. 

Did you also need a compatible window balance? If so, there are a few different options depending on the size of the spiral rod. Note that I'm referring to the rod that extends from the balance. Can you measure that for me? The best way to do it is to stand it straight up on a table, with the top side flat on the surface, and then measure the whole thing. Make sure that the rod is as fully retracted as it can go. Based on your cylinder size, it should be either 20-3/4" spiral or 21-3/4".