On August 9, 2004, about 1140 eastern daylight time, a Classic Aircraft Corporation Waco YMF, N723SR, was substantially damaged while landing at Hancock County - Bar Harbor Airport (BHB), Bar Harbor, Maine. The certificated commercial pilot was seriously injured, and two passengers were not injured. Visual meteorological conditions prevailed, and no flight plan was filed for the local commercial sightseeing flight conducted under 14 CFR Part 91. The pilot stated that he departed in the tailwheel airplane from runway 22, a 5,200-foot-long, 100-foot-wide, asphalt runway. During the takeoff the pilot noted that the windsock and automated weather observation system (AWOS) indicated a right-quartering headwind at 9 knots. After a 40-minute flight, the pilot returned to land on runway 22, and again noted the windsock indicated a right-quartering headwind. In addition, the AWOS reported the wind from 220 degrees to 310 degrees, at 10 knots, gusting to 16 knots. During the landing roll, with all three wheels on the ground, the airplane experienced a strong rear-quartering tailwind. The airplane began to veer left, and the pilot depressed the right brake in an effort to correct for the wind. The airplane subsequently nosed-over, and came to rest inverted in a grass area off the left side of the runway. The reported wind at BHB, at 1135, was from 300 degrees at 9 knots, gusting to 16 knots.