The pilot reported he was returning to the airfield as part of an 11-ship formation. The wind at the airfield was from between 220° and 230° and 7 to 8 knots. He landed the tailwheel-equipped airplane on the left side of the runway and kept the tail up during landing rollout to allow for spacing with the other aircraft in the formation. When he began to lower the tail to the runway, the wind hit the airplane' left side and lifted the left wing. Despite the pilot's control inputs, the airplane crossed to the right side of the runway, continued into grass, and came to a stop facing south. The left wingtip, aileron, and outboard aileron hinge struck the ground during the excursion, substantially damaging the airplane. The pilot reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation.