Power augmentation for multi-engine rotorcraft is of critical interest. But relying on overtemperature at the turbine inlet to meet this requirement will shorten turbine life unless a method of limiting thermal and mechanical stresses is found. A possible solution that was investigated involves allowing the turbine inlet temperature to rise to augment power while injecting water into the turbine cooling air to limit hot-section metal temperatures. An experimental water injection device was installed in an engine and successfully tested. The results demonstrated the potential for a significant increase in power while maintaining constant turbine blade temperature.