A noise control project has been completed by Northrop Aircraft, for the ground testing of the F89 airplane. Phases described include the prediction of performance, acoustical design considerations, correlation of acoustical and thermodynamic requirements, general construction, acoustical tests during construction, noise survey around the exposed airplane, and neighborhood survey around the completed installation. This noise suppressor is comparatively simple and inexpensive, requires no water cooling even for afterburner operation, and has proved adequate in terms of neighborhood relief and protection of operating personnel.