On July 22, 2008, about 1725 mountain daylight time, a Cessna 172M single-engine airplane, N7672, made a forced landing following a partial loss of engine power during takeoff initial climb from the Skypark Airport (BTF), Bountiful, Utah. The airplane was registered to a private individual, and operated by G&B Aircraft Management, Woods Cross, Utah, under the provisions of Title 14 Code of Federal Regulations Part 91. The certified flight instructor (CFI) and student pilot received minor injuries; the airplane sustained substantial damage to the fuselage and left wing. Visual meteorological conditions prevailed, and no flight plan was filed for the instructional flight. The local flight was originating at the time of the accident. The CFI reported that the accident flight was the first flight of the day for the airplane. Prior to takeoff, the student pilot "leaned the mixture for altitude" during a normal engine run up. The student taxied to the active runway, and proceeded to takeoff. As the airplane climbed through about 100 feet above ground level (agl), the airplane's climb performance degraded along with a partial loss of engine power. The CFI advanced the mixture to full rich, checked the carburetor heat, and verified that the throttle was full forward, but noticed no increase in the climb rate. The CFI then took control of the airplane, and initiated a forced landing to an open field beyond the departure end of the runway. During the landing roll, the wheels of the airplane sunk into mud, and the airplane nosed over. Examination of the airplane by a Federal Aviation Administration (FAA) inspector revealed that the airplane came to rest inverted within an open field about 1/4 mile north of BTF. Both left and right wing fuel tanks were full of 100-low lead aviation fuel. Examination of the Lycoming O-320-E2D engine, serial number L-22287-27A, by an NTSB investigator revealed no anomalies that would have precluded normal operation and production of power. No anomalies were noted with the airframe fuel system.