A Student Pilot reported hearing a loud bang during climb followed by the Cessna 150 airframe shaking violently; the engine coughed but kept running. Student and Flight Instructor returned to field where subsequent removal of the cowling revealed a massive crack in the crankcase.

Narrative

I was a student pilot on a dual instruction flight. During climb we heard a loud bang; the airframe shook violently and the engine coughed but continued running. My instructor took control of the aircraft. We were unsure what had happened and briefly discussed the possibility of a bird strike or other collision. We turned towards the airport and still had full power. Shortly after turning; oil spray was seen on the windscreen; confirming an engine problem. Oil temperature and pressure gauges were in the green. My instructor then returned control of the aircraft to me. Still having full power; I gained altitude as we continued to our point of origin. As we approached the airport and drew back power; the power decreased dramatically and was not as responsive as it should have been; as we tried to put some back. We safely made the runway landing with a tailwind and taxied to parking. I was at the controls during landing and taxi to parking. Removal of the cowling revealed a massive crack in the crankcase and a smaller crack. At no point did the engine completely lose power. No emergency was declared. Local CTAF radio calls were made to notify other traffic of our situation. The entire event spanned approximately 5-7 minutes. The aircraft had just returned to the line from maintenance to replace a cylinder.