How and where to install a battery tray can be tricky. Over the years I've witnessed multiple inflight battery ejections as a result of poor tray design, poor installation execution, or the use of low-grade velcro to secure the battery to the tray. Three basic practices I follow when designing a battery tray are: 1) Secure the tray to the landing gear mount, 2) Secure the battery to the tray using a screw-down locking method, not velcro, 3) Tray must be removable to allow servicing the tray or other components.
The following pictures show the various parts of the tray I designed used on the last three 2m planes, plus the final installed position. I use Fiberglass/Honeycomb Sandwich Panels from ACP Composites for the tray floor, locking plate, and circular screw hold-downs. Another great alternative for the tray floor is balsa/plywood carbon sandwich plates from Esprit Tech. These materials are much lighter and stronger than traditional lite plywood. that is typically used The tray floor is attached to graphite tubes using 2-56 screws with blind nuts. The graphite tubes are then secured to the fuselage sides with F3AU's Battery Tray Bracket Kit. Dowel hardpoints are added wherever screws passed thru the honeycomb panel plus reinforced those areas with 1/64th plywood. Hysol epoxy was used to attach the F3AU bracket mounts to the fuselage.
The tray is fully removable, very strong and durable, and firmly attached to the fuse sides and landing gear formers with a single screw located near the center of the tray floor. When this screw is tightened the floor rests on the gear mount formers which will prevent the tray from rocking or flexing during inflight G loads. The total tray weight is 58 grams.
Tray Components
