From the nasa website
For the 1905 aircraft
The brothers were able to solve this final problem by increasing the size of the elevator and rudder and moving the elevator and rudder farther from the center of gravity on the new 1905 aircraft. This increased the torque produced by the control surface and provided greater control for the aircraft. The radiator and fuel tank were moved back to the front strut and the size of the fuel tank was increased. The engine stayed the same as the 1904 aircraft and the weight was decreased to 860 pounds by eliminating the iron bars (70 lbs ballast in 1904 a/c) . The 1905 aircraft could be flown until the fuel tank was empty; staying in the air for more than a half hour, flying nearly 25 miles around Huffman's farm, executing turns and figure 8's, and flying more than 50 feet off the ground. The brothers now had a practical working airplane and began to market it to the War Department.
1903.....750 lbs (inc pilot) with 12HP motor - 505 sq feet wing area
1905......860lbs (inc pilot) with 18HP motor - 505 sq feet wing area
lbs = pounds (weight)