What occurs when smaller or fewer injector orifices are used in an ideal hybrid rocket motor while keeping oxidizer weight constant?

Using smaller or fewer injector orifices in a hybrid rocket motor while keeping the oxidizer weight constant results in decreased average thrust. This is primarily because the reduced number or size of orifices restricts the flow rate of the oxidizer into the combustion chamber, which significantly impacts the combustion characteristics.

While the total impulse, which is the product of thrust and time, may not change immediately, the change in flow characteristics alters how effectively and rapidly the combustion process occurs. The thrust is determined by the rate of oxidizer flow and the efficiency with which fuel is burned. With fewer or smaller injectors, the combustion may not reach the optimized levels that result in higher thrust output. Thus, the average thrust decreases as the oxidizer injection rate becomes limited, although the total impulse remains constant due to the oxidizer weight not being altered in the scenario.

This relationship emphasizes the delicate balance in rocket design and the critical role injector design plays in maximizing performance.