On June 7, 2004, about 1000 eastern daylight time, a Piper PA-28-140, N41916, registered to and operated by DeBenair Aviation Service, as a Title 14 CFR Part 91 personal flight, impacted into the Suzanne Lake at Chalet Suzanne Air Strip, Lake Wales, Florida. Visual meteorological conditions prevailed and no flight plan was filed. The private pilot and passenger reported no injuries, and the airplane incurred substantial damage. The flight was originating at the time. The pilot stated he positioned the airplane at the beginning of runway 36 for a soft-field takeoff noting the turf runway was wet; however, he failed to extend the flaps to the 25 degree setting (2nd notch). He selected an abort point halfway down the runway, advanced power for takeoff and pulled back on the yoke. The takeoff roll was progressing but the airplane was not accelerating sufficiently for takeoff. He lowered the nose to gain additional speed for the takeoff. He noticed the airplane had passed the abort point and aborted the takeoff. At that point he judged the remaining runway inadequate for stopping and advanced the throttle to full power. The airplane became airborne but did not climb when it reached the steep down slope departure end of the runway just before the lake. The airplane contacted the lake coming to rest 15 feet into the lake in about 5 feet of water at an azimuth heading of 180 degrees. He and the passenger exited the airplane without assistance. The pilot stated there were no mechanical failures or malfunctions to the airplane or any of its systems prior to the accident.