I have just finished the first revision of my full frame. The arms are designed to be very ridged in every bending moment. I added anchor points to the arms about half way out. This will allow me to attach stay wires that will also help keep the frame ridged. The hub is designed to break at bolted connection to the arms in the event of a hard crash. The hub has the fewest parts and would be easiest to replace. The arms can fold together for compact storage. The hole in the hub is designed to accept an electronics package. The electronics package can be loaded and unloaded with a few simple screws. This gives me flexibility to re-design with ease and produce several different arrangements for different missions. There is also room to add a retractable landing gear set. So far, the total weight comes out to be about 112 grams. Progress is slow, but coming along as I have the time.