- The protection of aircraft against shoulder fired heat seeking missiles is of growing concern in the aviation community. This paper presents a simple method for shielding the infrared signature of a jet engine from heat seeking missiles, by using water injection. The experimental results presented herein were obtained using a small (1 kN thrust) turbojet. Water was first injected at a mass flow rate of 13% of the mass flow rate of exhaust gases, reducing the temperature and producing some shielding. Water was then injected through a manifold at a mass flow rate of 118% of the mass flow rate of exhaust gases; producing a substantial reduction in temperature and complete shielding of the infrared signature. Results are presented in the form of thermocouple data and thermal images from the experiments. Freund Publishing House Ltd.