RE: The Unofficial all things Jet drive thread
You might want to read [link=http://forums.offshoreelectrics.com/showthread.php?32344-HOBBY-KING-Jet-pump]this review[/link] of the HK jet pump. Seems it has some problems that need to be addressed before use. On the flex shaft, it is not needed. You should use a direct coupler of the flex type (with the silicone or rubber insert). [link=http://www.sdp-si.com/web/html/couplings.htm] These folks [/link] have a good assortment - look up flex couplers in their catalog. Looking forward to seeing your build, Sdg.