General aviation Flight Instructor reported an engine malfunction during climb on a training flight. The instructor maneuvered to land on the opposite direction runway.

Narrative

My student and I were practicing traffic patterns for landings. After our sixth touch and go; we were making a climbing left turn from crosswind to downwind to reach pattern altitude; which is 1;100 feet. At around 900 feet; the engine sputtered; and we experienced a significant loss of RPM; dropping to about 1;500. I attempted to increase the throttle and quickly performed the emergency memory items; but I couldn't regain engine power. The propeller was still spinning; but we were down to around 700 or 800 feet; positioned between midfield and abeam the Runway XX numbers. At that point; I decided to land on Runway XX; assuming we wouldn't be able to return to Runway XY or XZ; even though Runway XY was being used for the pattern. I turned directly toward the Runway XX numbers while contacting the tower controller. Due to my panic and fast talking; the controller initially had difficulty identifying who I was. Eventually; the controller understood my situation and intentions and rerouted two aircraft on final for Runway XY while I executed an emergency landing on Runway XX. I managed to get the plane down safely; and there were no other traffic conflicts.