I am working on a hexacopter using 12 motors in a coaxial configuration but connecting the motors with a y connection. I have been reading everything I can about coaxial motors and the configurations. With the design I am doing i was thinking on doing a dihedral top 6 motors and strait bottom wondering if the air flow will cause the bottom motor to work too hard because the airflow will not be in a direct line. Thought it might be worth a try but if there is any suggestions otherwise or someone has already tried this with bad results I would be happy to hear. I am using 12, DJI e300 motor-esc's that I have. With all the talk about the bottom motor just pushing air that is already sped up and possible losing ??% efficiency thought it might be worth a try. It will put a large amount of air from the top motor outside of the bottom flow and also cause the bottom motor to actually work to push the air down?
Right now I am working on new upper-lower plates from cf for a hex with 6-4108 480kv and 15-5.5 on a turnigy hexacopter frame just making the plates approximately 8" across flats and changed to 330mm cf tubes, making more room for everything. I have a cnc router table that I am cutting the plates with and the designs will be done this weekend.