On September 26, 1993, at 1150 Pacific daylight time, a Ercoupe 415C, N3561H, sustained substantial damage following an on ground loss of control during the takeoff ground run at Columbia, California. According to the pilot's verbal statement, the aircraft began porpoising during the takeoff run and the nose gear collapsed during repeated impacts with the runway. The aircraft was owned and operated by the pilot. Visual meteorological conditions prevailed at the time and no flight plan was filed. The aircraft incurred substantial airframe damage to the engine firewall. The certificated private pilot, the sole occupant, was not injured. The flight was originating as a personal cross country flight to Livermore, California. The pilot had recently purchased the aircraft and had only 6 hours in type. He reported that on the takeoff ground roll as the aircraft accelerated through 42 mph indicated, the aircraft began to liftoff. The pilot noted that he had been instructed to lift off at 55 mph, and, "not wanting to stall or mush," he applied down elevator to keep the aircraft on the runway. The aircraft began to porpoise, then veered off the runway after the collapse of the nose landing gear.