I am mainly concentrating on smaller multirotors, but a few friends have some and now and again I get to work on them.
Recently I have helped the Prof wire up and fault find an aluminium quadcopter. This "Hospital Quad"....so called because you would end up in hospital if it hit you has been a real beast to tame.
I wired it up as per the instructions, but for some reason it flies completely backwards. I cobbled the wiring together and added in some undercarriage made from pipe insulation (Which actually works really well). On Saturday we crashed this many times and had to go back to my garage to rebend the frame, but it still flies. I seem to have a real problem flying this one and for some reason put in opposite commands from time to time. One crash of mine was at full speed onto tarmac. It rolled about 5 times and looked done for, but after some extensive work with a hammer and a vice we managed to fly it again late in the evening. It was pitch black and take off was aided by a torch, but there is still life in the old girl yet. Aluminium seems a really silly material to make it from, but as you just rebend it back again, maybe it's not so stupid after all! What is incredible is how fast it is.....really fast and quite frightening when it is heading your way. You wouldn't be able to dodge this one, so it is a bit of a handfull. We both learned a lot about setup of a larger quad and if we can keep it flying whilst we learn and design a replacement so much the better.
Next on the bench was a design of mine. I aquired an Hobby king "Orca" frame and some discarded motors and speed controllers, so I had all the bits to build my own larger quad.
I also didn't like the motor booms so I fabricated my own on my 3D printer. I am toying with the idea of putting in some shear pins so the booms fold on impact. This Fabricated Orca or F-Orca! for short took about 3 hours to wire. Unfortunately when I powered it up one of the motors burnt out and the ESC gave off some tell tale magic smoke. This one shall remain a work in progress until I can replace the parts. The wiring does look good, so maybe the second hand parts have a fault somewhere.