In a statement provided by the commercial pilot, he was transporting his newly acquired vintage bi-wing airplane to his home field. About 21 miles from the destination, the airplane encountered severe turbulence. The pilot attempted to approach the home airport from a different direction, but still encountered severe turbulence. Storms were visually detected by the pilot approaching the destination airport, so he diverted to avoid the storms. The pilot headed towards a private airfield and visual acquired what he thought was the landing area. The pilot performed a landing to an open, plowed, field. During the ground roll, the landing gear dug into a dirt bump, the airplane nosed over, and came to rest in the inverted position. The airplane's rudder was substantially damaged.