Analog computers in propeller control design

IN THE PROCESS of designing and developing a dynamic system, provisions should be made for analysis of the performance of the system while it is still in the design stage. One method of analysis is to write the equations of motion of each moving part and then combine these equations in such a manner that a means of solution would be possible. This method is satisfactory if the system has few moving parts and, thereby, does not require many equations to describe its behavior. For a highly complex system, this will prove to be very laborious by longhand methods and should be submitted to machine computation for solution. The motion of the parts of the system may be such that an equation describing the behavior of any one part may be difficult to write unless approximations are made, and may have to be directly simulated by a device which has the proper dynamic characteristics built into it.