With a constant manifold pressure set during a climb, the power output from a supercharged engine:

In a supercharged engine, the supercharger is designed to compress the intake air, allowing the engine to maintain a higher manifold pressure compared to naturally aspirated engines, even at increased altitudes. When climbing, atmospheric pressure decreases, which would typically lead to a reduction in engine power output due to less dense air entering the engine. However, with a constant manifold pressure set through supercharging, the engine compensates for this decrease in ambient pressure.

In this scenario, the supercharger works to provide additional pressure to the intake air, thus enabling the engine to maintain its performance levels. As the pilot climbs and the atmospheric conditions change, the supercharger continues to deliver the necessary air volume, allowing for increased power output compared to what would occur with a naturally aspirated engine. Hence, the power output from the supercharged engine increases as it compensates for the altitude-induced pressure drop.