The pilot reported that he and his passenger were completing a personal flight in an unregistered, experimental airplane that was not equipped with carburetor heat. They departed and flew the traffic about 800 to 1,000 ft above ground level (agl) and the engine was operating about 6,000 rpm. He turned on the left base leg and decreased throttle to about 4,000 rpm, and descended to about 600 ft, when the engine lost power. He stated that the engine acted the same as the last time he experienced carburetor icing. The airplane descended quickly, and he did not flare properly, which resulted in a stall, and subsequent impact with the runway. The pilot and passenger egressed without further incident and a post impact fire consumed a majority of the wreckage. The pilot reported that there were no mechanical malfunctions or failures that would have precluded normal operation and added that the loss of power was due to carburetor ice. Due to the post impact fire, an examination was not completed. The airplane was operating in an environment that was conducive to serious carburetor icing at glide power settings.