The pilot reported that he was preparing the homebuilt airplane for its first flight for the owner. He said that on the morning of the accident the airplane's engine was run for approximately 30 minutes for break-in at full power. After the engine run the cowling was re-installed and the engine run for an additional 15 minutes. Subsequently, the pilot performed taxi testing of the airplane. He had made 2 taxi tests to about 40 miles per hour which he estimated would be approximately stall speed for the airplane. He stated that on the third taxi test, when about two-thirds of the way down the runway, a gust of wind caused the airplane to become airborne. The pilot stated that when he was able to get the airplane under control there was insufficient runway remaining to perform a landing and he decided to continue and return for landing. He stated that this was to be a taxi test only and that he had no intention to fly the airplane at that time. While attempting to climb, the pilot noticed that the engine speed was too high and he was not able to climb effectively. The pilot attempted to turn the airplane back to the airport to make a downwind landing, but the airplane began to stall. He stated that he lowered the nose and determined that he would not be able to make the runway. As the airplane's altitude decayed, the pilot pulled back on the stick and the airplane struck the ground. The pilot stated that he believed that the pitch setting of the airplane's propeller was improper which did not allow proper thrust production for flight. During the accident the propeller blades were fragmented and determination of the installed pitch setting could not be obtained.