Abstract: The present invention provides processes for the production of polyurethane wind turbine blades and other large objects. The inventive process involves forming a mold for the polyurethane wind turbine blade at a wind farm site, injecting an isocyanate and an isocyanate-reactive component with an automated reaction injection molding (“RIM”) machine into the mold, closing, pressing and heating the mold to cure the resulting polyurethane and installing the polyurethane blade in the wind turbine. Alternatively, the process involves forming a mold for polyurethane wind turbine blade at a wind farm site, injecting an isocyanate, an isocyanate-reactive component and long fibers with an automated long fiber injection (“LFI”) machine, closing, pressing and heating the mold to cure the resulting polyurethane and installing the polyurethane blade in the wind turbine. Because the inventive manufacturing process occurs at the wind farm site, transportation problems are obviated.