US Patent 10894593 UAV with frangible airframe structures

A mechanical joiner for an airframe includes a joiner core and first and second caps. The joiner core has a first side with a first cradle shaped to hold a first structural member and a second side with a second cradle shaped to hold a second structural member. The first cap is shaped to mate to the first side and clamp the first structural member into the first cradle. The joiner core includes a first hole for a first mechanical fastener to extend through and across the first cradle and secure the first cap to the joiner core. The second cap is shaped to mate to the second side and clamp the first structural member into the second cradle. The second cap includes second holes for second mechanical fasteners, distinct from the first mechanical fastener, to secure the second cap to the joiner core.