On September 3, 2001, at 1448 central daylight time, a Gelasi Aircamper, N7172B, piloted by a private pilot, sustained substantial damage during an in-flight collision with terrain following a loss of control during initial climb after takeoff. The aircraft had departed runway 27 (1,775 feet by 130 feet, dry/turf) at the Vincent Airport, near the town of Bloomfield, Wisconsin. Visual meteorological conditions prevailed at the time of the accident. The flight was operating under the provisions of 14 CFR Part 91 and was not on a flight plan. The pilot and his single passenger sustained serious injuries. The flight was departing at the time of the accident and had the intended destination of Palmyra, Wisconsin. According to the pilot's written statement, during the initial climb after takeoff the airplane began to sink rapidly and the pilot lowered the nose of the airplane in order gain some additional airspeed. The pilot reported that he cleared a fence and a line of trees that border the airport area. The pilot stated that there was a second line of trees and he started a shallow climb to clear the trees. The pilot reported, "I just barely cleared these and knew enough to keep the plane from banking or yawing to eliminate the chance of a stall, however at this point I think my passenger in the front seat decided to turn around & see what I was doing. I think his [right] leg pushed the stick over & the plane went into a left bank. All my effort to right the stick would not do it & being too close to the ground I could not recover control before we struck the ground... ." The pilot stated that witnesses to the accident saw the airplane clear the second row of trees, yaw to the left, and then bank to the left. The pilot reported the left bank, "... caused us to loose what lift we had." A written request for a passenger statement was made, and as of the date of this report no response was received. Delivery confirmation of the request is attached to this report.