The airplane was substantially damaged when the right wing struck a vehicle on a roadway adjacent to the runway during a go-around attempt. The pilot and passenger reported no injuries. The pilot stated that he entered a left downwind for runway 36 (2,108 feet by 100 feet, turf) at Big Foot Airfield (7V3), Walworth, Wisconsin. He noted that the downwind, base and final traffic pattern legs were "normal." He reported that the final approach flown would have allowed the airplane to touch down within the initial one-third of the runway length. He stated, "Close to touch down I experienced a float and what I believe was a strong wind shear." He reported that he applied full engine power and initiated a go-around, however, the right wing tip subsequently struck a minivan on an adjacent roadway. The airplane continued approximately 600 feet and came to rest in a cornfield. The pilot reported no malfunctions or failures with the airplane prior to the accident. He noted that the accident might have been avoided by initiating a go-around "at the first sign of any trouble especially on a runway that is only 2100 [feet] long."