On May 18, 1996, at 0700 central daylight time (cdt), a experimental Rans S6ES Coyote II, N4307N, sustained substantial damage when it collided with a concrete wall along the east side of runway 16, during takeoff, from the Hays Airport, Hays, Kansas. The private pilot of the 14 CFR Part 91 flight, and the passenger were uninjured. Visual meteorological conditions prevailed at the time of the accident, and no flight plan was filed. The pilot reported on the NTSB form 6120.1/2, that the wing flaps were set at approximately 20 degrees for takeoff. After takeoff, the wing flaps were partially retracted by one notch. He reported that after retracting the flaps the airplane stalled, and settled back onto the runway. After settling back onto the runway the aircraft departed the runway to the east. The pilot did not report any airplane or engine malfunctions. Aircraft damage was reported as a crushed firewall, a broken windshield, bent wing lift struts, and a bent right wing. The airplane's left wing spar was broken, and the left horizontal and left elevator were sheared off.