The Turbax 46 ducted fan units arrived. I had a little setback when I went to buy these units. I found out that you can no longer buy units for the older K&B .45's, which have the carburetor in the front. Newer ducted fan engines have the carburetor in the back. I had to return to my original plan of using new OS .46 VX-DF ducted fan engines. It will be a while before I can purchase those. The fans require a little bit of assembly. The Turbax 46's are set up for the OS engines. Turbax I fans won't work with the OS engines.