Research studies focusing on jet engine test cell aerodynamics, acoustics, and cell flow characteristics as affecting engine performance can be conducted with scale models for a variety of test cells. Such studies require the simulation of a number of jet engines in rather accurate detail, both as to geometry and as to flow characteristics. It has been demonstrated that simulators of low-bypass afterburning turbojets, high-bypass turbofans, turboshaft engines (without propellers), and inducted fan engines can be designed, fabricated, and successfully operated using either high-pressure air ejector systems or turbine driven systems for the motive power. The peculiar problems associated with scale model testing and engine simulators and the methods which can be used to attack these problems are described.