I've modified my F-877A-1 battery tray to accept two EarthX 900-VNT batteries, side by side, with a contactor for each. I checked the loads, and it's well over-strength and quite stiff.
The extra pieces are cut from the spare angles in the fuselage kit, plus a floor of 0.032" 2024-T3. Was able to cut the F-877C battery hold down in half, with just enough length to span the EarthX batteries.
Structure is assembled with MS20426AD4 solid rivets. For securing the hold-down bolts, had to use MS21051L4 single lug plate nuts on underside of battery box and trim the corners of the adjacent angles for clearance.
The assembly installs to the baggage ribs using the same fastener locations as for the standard battery tray. The centre two holes use AN509-10R9 screws, and the four forward and aft fasteners are replaced with MS27039-1-11 pan head screws. The spanwise angle flanges are a bit light on edge distance for the pan head screws, but all screw loads except tension will be carried by the original F-877A-1 battery tray.
The extra pieces are cut from the spare angles in the fuselage kit, plus a floor of 0.032" 2024-T3. Was able to cut the F-877C battery hold down in half, with just enough length to span the EarthX batteries.
Structure is assembled with MS20426AD4 solid rivets. For securing the hold-down bolts, had to use MS21051L4 single lug plate nuts on underside of battery box and trim the corners of the adjacent angles for clearance.
The assembly installs to the baggage ribs using the same fastener locations as for the standard battery tray. The centre two holes use AN509-10R9 screws, and the four forward and aft fasteners are replaced with MS27039-1-11 pan head screws. The spanwise angle flanges are a bit light on edge distance for the pan head screws, but all screw loads except tension will be carried by the original F-877A-1 battery tray.