In most cases, especially in general aviation, the weight of the cooling system should be reduced. In air cooled engines it is necessary to optimize the system taking in account structural features and manufacturing process. This optimization is customary performed by Finite Element Methods (FEM) or similar methods.The main purpose of this paper is to present a way to do the spadework on this problem in order to optimize CPU time of the computer using a simplified approach to obtain approximate values of the more important design parameters of the cooling system.Main assumptions and equations to solve the problem are described for different configurations. Air pressure drop in the system is evaluated checking if it is in good agreement with experimental results. The released software can be installed in a PC, allowing to obtain a first approach of the problem very quickly.