On July 8, 1996, at 2035 central daylight time, a O'Day Sonerai II-LS tailwheel equipped, experimental airplane, N30155, registered to a private owner, collided with a tree while approaching to land at the Polly Ranch airstrip near Friendswood, Texas. The airstrip is approximately 10 miles south of Houston, Texas. The airline transport rated (non-owner) pilot-in-command and his one pilot rated passenger received minor injuries and the airplane sustained substantial damaged. The Title 14 CFR Part 91 personal flight originated at Clover Field, Texas at about 2025, and the intended destination was the Polly Ranch airstrip. Visual meteorological conditions prevailed and there was no flight plan on file. Shortly after the mishap, the passenger told Federal Aviation Administration (FAA) inspectors who visited the site that the pilot initially flew the airplane down the Polly Ranch airstrip an altitude of about 300 feet and that on the down wind leg of the traffic pattern the pilot flew the airplane about 100 feet above the trees. As the flight was approaching the end of runway 11, she noticed that they were close to the ground. Just as she was about to advise the pilot of her observation, he banked the airplane toward the runway. Subsequently, the engine either quit or went to idle and the plane collided with a tree near the end of runway 11. Counsel for the pilot (both former flight students of the pilot) reported that the plane's engine began to run rough while the airplane was on the crosswind leg of the traffic pattern and the airplane collided with a tree before the pilot could land on the runway. The plane's engine stopped running just prior to the collision. The airplane did not reach traffic pattern altitude after it departed Clover Field because it was such a short distance between the two airports. (Note. The two airstrips are 3 1/2 nautical miles apart). The pilot did not know the climb speed or stall speed of the aircraft as loaded and under the conditions which it was being operated. Witnesses reported that the airplane approached the airport at an altitude that was lower than what they were normally accustomed to seeing. They characterized the plane's altitude on the downwind leg of the landing pattern to runway 29 as "very low just above the house", and "extremely low". The plane was observed to enter a steep right bank near the approach end of runway 11. Subsequently, its nose pitched down and it collided with a tree. None of the witnesses reported hearing or observing a problem with the plane's engine. The plane's engine was torn from its mounts during the accident sequence, and its wings and fuselage were extensively damaged. An examination of the plane's engine by the owner of the airplane in the company of FAA airworthiness inspectors revealed that the carburetor flow jet needle was displaced 15 degrees from the desired setting. The cause of the displacement could not be determined.