On October 13, 2006, about 1325 Pacific standard time, an experimental Finney Thorpe T-18, N467JF, ground looped after landing on runway 28L at Montgomery Field (MYF), San Diego, California. The private pilot/owner operated the airplane under the provisions of 14 CFR Part 91 as a personal flight. The airplane sustained substantial damage to the right wing. The pilot was not injured. Visual meteorological conditions prevailed for the local area flight. The airplane departed at an unknown time from MYF. The National Transportation Safety Board investigator-in-charge (IIC) interviewed the pilot. The pilot reported that there was a direct crosswind of about 10-15 knots. He made a normal approach and landing. On the landing rollout, the airplane ground looped, and bent the right wing. The pilot stated that there were no mechanical anomalies with the airplane. According to tower personnel, the airplane bounced on landing, porpoised down the runway, and struck the ground in a right wing low nose down attitude. The recorded routine aviation weather report (METAR) issued for MYF at 1253 indicated: winds from 170 at 7 knots; visibility 10 statue miles; a scattered cloud layer at 6,000 feet; temperature 21 degrees Celsius; dew point 11 degrees Celsius; and altimeter 29.81 inches of Mercury (inHg). At 1325, the recorded winds were from 230 degrees at 9 knots. At 1353, the recorded winds were from 220 degrees at 11 knots.