greasymoney 4/1/2010Sure you can! It is usually a horrible idea, though.
In newer vehicles, the fan clutch is designed to save fuel and help keep the engine temperature at optimum for better emissions, fuel savings, and reduced engine wear.
A fixed blade fan will cost you more fuel, may cause problems due to overcooling, and may suffer catastrophic failure by flying apart.
Replacement with a quality, thermostatically controlled, professionally installed electric fan is a good option, but will usually cost a nice chunk of change for negligable benefits.