On June 15, 2001, at 1915 eastern daylight time, an experimental certificated Bucker Jungmann C.A.S.A. 1.131 airplane, N131HH, was substantially damaged during landing at the Plymouth Municipal Airport (PYM), Plymouth, Massachusetts. The certificated private pilot/co-owner was seriously injured. Visual meteorological conditions prevailed and no flight plan was filed for the personal flight conducted under 14 CFR Part 91. In a telephone interview, the pilot stated that PYM consisted of two runways; 15-33, and 6-24. A grass strip which was about 2,000 feet long and 200 feet wide was located parallel to runway 24. A taxiway was located adjacent to runway 15-33 and perpendicular to the approach path for runway 24. The taxiway was elevated slightly higher than the upwind grass area where the airplane normally touched down. The pilot reported that she routinely practiced landings on the grass strip parallel to runway 24. On the day of the accident, she performed 3-4 landings with the co-owner of the airplane, and then continued to practice landings by herself. She performed about 4-5 additional landings and during the last landing she "came in low," and the main landing gear impacted a runway sign. The airplane came to an abrupt stop in a nose-low attitude. The pilot reported that when the airplane impacted the runway sign, she was looking to the side of the airplane to maintain clearance from the taxiway. She stated she never saw the runway sign, and reported no mechanical deficiencies with the airplane. According to the co-owner of the airplane, he performed 3-4 landings with the pilot and then exited the airplane. He observed the pilot perform 3-4 additional landings, and during the last landing, he noticed that the airplane had a "lower than normal approach." The co-owner stated that the airplane "settled" over the taxiway, and the landing gear impacted the runway 15-33 sign. The airplane continued to travel about 30 feet and impacted the ground in a nose low attitude. The co-owner reported the wind was "right down the runway" at about 8 knots. Examination of the airplane by a Federal Aviation Administration (FAA) inspector revealed the propeller was broken off the engine, all three landing gear wheels were separated from the airplane, and the firewall was "caved in." According to the inspector, tire marks were observed on 18" of the taxiway adjacent to runway 15-33, and impact marks were noted on the runway 15-33 sign about 24 feet from the taxiway. The airplane came to rest 40 feet from the runway sign in a 10-degree nose down attitude. The inspector observed no mechanical deficiencies with the airplane. Weather reported at PYM, at 1852, included wind from 190 degrees at 7 knots, 10 miles visibility, and clear sky. The pilot reported 146 hours of total flight experience, 30 hours of which were in make and model.