The Sterling Yak-9 was my first "big" CL model. I flew it on 52' lines with a nicely broken-in McCoy .35 ($5.98 special). I had a ball with it, and leaned out, it flew with no problems at all. Of course I knew nothing of "the pattern", but did horizontal lazy-8's, wingovers, and vertical lazy-8's, which were sometimes successful, a significant accomplishment, since they did not fill up much more than 60-70 degrees. Mine had flaps and the V-shaped flap connector. The plane is sort of short-coupled for flaps, but mine was purely stock and flew quite well. I lovd that plane! I built another, started around 1960 and finished in 2002, after my 40-year hiatus. It's too heavy.