The computer aided design of the wind tunnel setups used in the performance evaluation of blowers, and a new tractor mounted air carrier centrifugal blower for cotton crop. A computer aided design was prepared according to the AMCA (The Air Movement and Control Association) guidelines to obtain the specifications of the wind tunnel setup for the different blowers. The wind tunnel setup consists of the transition section, flow straightener and the tunnel. This paper deals with the fabrication of the various parts of the newly designed tractor mounted air carrier centrifugal sprayer. The techniques and equipment used for the performance evaluation of the centrifugal blower assemblies in the laboratory are also discussed. ___________________________________________________________________________________ Keywords: Computer Aided Design, Wind Tunnel, Performance Evaluation, Centrifugal Blower, AMCA