I built my first FT Arrow and loved it. It is a great plane and a lot of fun. However, I had issues with batteries, overall toughness, and the power pod constantly shoving itself too deep in the fuselage resulting in the prop rubbing. The plane was designed around an 800mah 3S battery, but all of my 3S's are 1300 or larger. My smallest one is a 1000mah 4S, which is essentially the same size. Anyway, many good crashes with too much weight in a fuselage that was overstuffed, resulted in my first Arrow splitting down the middle from the stress. Time to design an alternative! My goals were to create a tougher, one-piece design, that would allow those precious few extra millimeters of battery space, while providing better motor and component mounting. I came up with the attached design in my head, but I have no skill with CAD programs, so my buddy Henry aka RomulanAle here on Thingiverse did the drawing work for me. I told him exactly what I was looking for, and together we came up with this awesome part!
-one piece with solid mounted firewall
-no mods to the rest of the plane
-firewall has standard "full size" 16x19 mount holes for 220X motors
-"mesh" design allows great electronics cooling, while giving tons of options for zip-tieing components
-space for batteries up to 2200mah (I plan to use 1300 3S)
-still plenty of surface area to glue or tape the top of the wing
-better protection for FPV camera in a head-on crash
-no longer swappable
-if you use too much hot glue in the build you'll make a mess on your electronics
-a few cents worth of printer plastic is still more expensive than foam board
***Take care when mounting your motor... depending on how your shaft protrudes out the bottom, you may have to trim the center hole slightly. I designed it around a Cobra 2204, but I ended up having to trim with a hobby knife to allow the C clip on the Emax 2204 shown in the pics to spin freely. Enjoy, and have fun!!
I used PLA, but I'm sure other materials would work fine. My printer has a 200x200mm platform, and the fuse is exactly 200mm long. I placed it top down diagonally across my bed, and it printed with no problems.