Why not replace your existing windmill head with a new one?  This is much cheaper than buying a complete system, especially if you already have a tower. 

Upgrade your system:

• Higher output compressor - up to 4.5 CFM
• Longer blades and bigger head (73") allowing you to catch more wind
• One piece hub assembly.  Attaches to our compressor with 2 set screws and a thru bolt on the end (5 minutes to install and it will not come off).
• Larger airline (1/2") - can connect into existing 3/8" airline if needed
• Better quality airstone with a built in check valve
• Industries only 5 year compressor warranty! 
• Made in the USA (not imported)

This comes with the complete head, blades, one piece hub assembly, functional compressor, tail arms and tail fin.  It also includes 100' of airline and 1 airstone diffuser with a backflow valve.  Fits any windmill with a 2" receiver for the pivot tube.  We also sell replacement cones.

We also sell these as Ornamental windmill heads for $100.00 less - they have a non-functional compressor.