hi,

For mine, I glued a plywood plate to the bottom of the fuselage to support the main tank. 2 long cable tie looped through a pair of holes I made on the plywood plate (on either side of the tank, front and back) straps it in place. I also epoxy glued several cable tie holders (http://www.avbcable.com/1-x-1-adhesi...white-100pack/) with the adhesive tape on their mounting surfaces removed and roughened with a file to the sides on the tank. The cable tie loops through these cable tie holders as well. These prevent the tank from moving forward and back.

Hope this helps.

Isaac