Abstract: Gas generators with low injection pressure drops can effectively reduce the pressure rating of the supply system, offering significant potential for cost reduction and performance improvement. Nevertheless, achieving highly efficient and stable combustion under low injection pressure drops remains a considerable challenge. In this paper, a low-pressure-drop spray combustion scheme was proposed, utilizing an air/ethanol propellant with a film-cooled injector faceplate. A series of experimental studies were conducted on the performances of the gas generator, including ignition and start-up characteristics, combustion stability, and combustion efficiency. The results indicate that ignition was difficult during ethanol-pre-pressurization phase, whereas stable ignition were achieved with a sustained ignition duration of 260 ms after the ethanol flow reached full conditions. Combustion stability is significantly affected by the length of combustion chamber, when the combustion chamber length-to-diameter ratio was increased from 2.5 to 5.0, the dominant frequency of pressure oscillation rose from 104 Hz to 192 Hz, and the power spectral density decreased from 0.008 MPa²/Hz to 0.0043 MPa²/Hz, effectively mitigating low-frequency combustion instability. A combustion efficiency of 98%～99% was achieved with an air injection pressure drop of approximately 0.2 MPa and an excess oxidizer coefficient ranging from 1.01 to 1.06. Furthermore, under conditions of 1.28 MPa chamber pressure and 2200 K total temperature, the gas generator made of ordinary 304 stainless steel without active cooling successfully passed a long-duration hot-fire test of 32 seconds. No structural melting or ablation was observed, confirming the feasibilities of the film-cooling approach for this high-temperature combustion device.