Back in the early to mid 1970s, I began construction on one of these Sterling Cirrus sailplanes. It got put aside when I bought my first radio control system (a used 3-channel OS Digital). In a somewhat desperate attempt to own an RC glider, I actually crammed two huge servos, a huge receiver, and a NiCad airborne battery pack (the only part that has not gotten smaller in 30 years) in the cockpit. Although the cockpit was very spacious, the balsa frame construction was way too weak to support a radio system, but that didn't stop me... well, not right away anyway. If I remember correctly, the wingtips had a chord of about 1" and were about 3/16" thick.
After much work covering the undercambered airfoil and compound curves around the fuselage with Japanese tissue, it was finally ready to fly. It probably weighed three or four times the weight listed on the box top. The first couple "flights" consisted of tossing the Sterling Cirrus off a little ridge about 3 feet high, at Klinkin's Field, in Mayo, Maryland. The flimsy wings flexed up into an extreme curve - it's amazing that they didn't break. The landings were in soft, long grass, so the craft survived. That wall all well and good, but it was not exactly satisfying flying. Somehow, I talked my father, who was skinny but was no athlete, into running with a tow line in an attempt to get it aloft. Between the two of us, the Cirrus was rendered unusable after about an hour. Oh well, live and learn (or don't learn).
This kit was recently (April 2008) on eBay. The price was at $56 with 6 hours to go.