The airplane crashed at about 1035 Eastern time while attempting a takeoff. Visual conditions prevailed; instrument flight plan had been filed. The private pilot received serious injuries, and two passengers received minor injuries. The pilot later said the takeoff roll had been uneventful; however, after rotating and at about 50 feet agl, the flight controls became mushy, and he did not have any elevator or rudder control. Witnesses observed the airplane lift off about 1100 feet down the runway. As it climbed, its wings began to rock and the airplane began to porpoise. They further stated it appeared the airplane simply ceased flying and descended, impacting the ground. The engine sounded as if it was operating normally, and the propeller had also been rotating throughout the takeoff.