The airplane stalled after takeoff and collided with a tree. The pilot stated that he previously ground looped the airplane in December 2006, which resulted in the necessity to replace the left wheel assembly. A borrowed left wheel assembly was installed with the brake drum facing outboard, rendering the left brake inoperative. The purpose of the accident flight was to perform taxi testing at increasing speeds in an effort to determine rudder effectiveness, and also for personal experience; no static engine run-up was performed before applying power to begin the taxi test. The airplane was taxied onto runway 15, and power was applied to begin the taxi test, but the airplane inadvertently became airborne. After realizing that the flight was airborne and there was insufficient runway remaining to land and stop the airplane, he applied full power and attempted to turn 45 degrees in order to land on a closed grass runway. The airplane climbed in ground effect, stalled, and collided with trees. He reported that the "...engine was 'overpropped' and thus not producing maximum horsepower." He also recommended more static testing of the engine/propeller combination.