On February 27, 1998, at 1130 central standard time, a Cessna 150G airplane, N3729J, was substantially damaged upon impact with terrain when the airplane overran the departure end of the airstrip during an aborted takeoff near Lonoke, Arkansas. The flight instructor and the student pilot were not injured. The airplane was being operated by a private individual under Title 14 CFR Part 91. Visual meteorological conditions prevailed for the instructional flight for which no flight plan was filed. The local flight originated from the North Little Rock Airport at approximately 1000. In the enclosed NTSB Form 6120.1/2, the flight instructor offered a detailed description of the instructional flight. The lesson planned for the 19 hour student pilot receiving instructions was concentrated on obtaining proficiency on soft and short field takeoffs and landings. The flight proceeded to the Carlisle Airport (4,500 feet concrete runway), where 5 soft field takeoffs and landings were made. The instructor added that he elected to take the student to the Sendero Airpark to give the student a chance to experience an "actual" soft field landing and takeoff. The flight instructor acknowledged that he was very familiar with the 2,200 foot airstrip since he had recently been there in several types of airplanes. Utilizing the soft field landing technique, the student pilot executed a successful landing on runway 30. For the departure from the Sendero Airpark, the flight instructor stated that he pointed out the pros and cons of the obstacles surrounding the airstrip and elected to depart from runway 12, which was also a customary local procedure at the airstrip. The airplane was configured for a soft field takeoff from the 2,200 foot grass airstrip. During the takeoff roll from runway 12, the wheels of the airplane encountered a "very wet and soft spot on the grass runway" and the airplane decelerated abruptly. The flight instructor took control of the airplane and closed the throttle to abort the takeoff; however, the airplane overran the end of the airstrip, impacted a drainage ditch and nosed over. The flight instructor added that he was not aware that the area had been subjected to heavy thunderstorms and hail the day before the accident. He also stated that "he hesitated for 3 to 5 seconds before making the decision to abort." See enclosed plot plan provided by the flight instructor additional details on the airstrip. Examination of the airplane by the FAA inspector revealed that the engine firewall and the left hand portion of the forward fuselage sustained structural damage. The nose landing gear assembly, the propeller, and engine cowling were also damaged. The FAA inspector stated that the operator had just completed the installation of a shoulder harness kit on the airplane two weeks prior to the accident.