On July 18, 2004, at 1527 central daylight time, a Mattie RV-4 single-engine homebuilt airplane, N464WB, was substantially damaged following a loss of control landing at El Reno Municipal Airpark (F28), near El Reno, Oklahoma. The commercial pilot and one passenger were uninjured. The airplane was registered to and operated by the pilot. Visual meteorological conditions prevailed, and a flight plan was not filed for the 14 Code of Federal Regulations Part 91 personal flight. The cross-country flight departed Twin Lakes Airport (2OK2), near Midwest City, Oklahoma, approximately 1500, with F28 as its intended destination. The 524-hour pilot stated in the Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1/2), that upon reaching F28, he elected to land to the north, due to the fact that "the winds were calm." After "slipping" the airplane to get on the proper glide slope, the pilot stated that the airplane touched down within the first few hundred feet of the runway, had a "slight bounce," and he added power to correct it. The airplane started to veer left so the pilot increased right rudder, with no effect. The pilot continued to add right rudder to the point that he over-corrected and the airplane began veering to the right. The airplane exited the paved surface of the runway, and the pilot added power to try to execute a go-around. The pilot noted that "due to the high density altitude, high gross weight, and aft center of gravity," the go-around had little effect. The airplane proceeded across the taxiway and back onto the runway "where the right landing gear collapsed due to the high side load." According to the Federal Aviation Administration (FAA) inspector, who responded to the accident site, the aircraft was landing to the north at F28 on runway 35 (a 5,600 foot long and 75 foot wide concrete grooved runway). Upon touchdown, the airplane veered off the runway and the right main landing gear collapsed. The airplane came to rest on an approximate heading of 270 degrees. The pilot reported structural damage to the right main landing gear attach point. At 1453, the automated surface observing system at Wiley Post Airport (PWA), located approximately 18 miles east of F28, reports winds from 030 degrees at 7 knots, visibility 10 statute miles, clear skies, a temperature of 88 degrees Fahrenheit, dew point 64 degrees Fahrenheit, with a barometric pressure reading of 30.00 inches of Mercury. The field elevation was 1,417 feet mean sea level. The density altitude was calculated by the investigator-in-charge at 3,575 feet.