We have done a fair amount of research, and have ended up with a reasonable idea of how to structure a UAV. If you spot any weaknesses or problems, please do not hesitate to reply.
We are building a 'Hexacopter’, since we need stability and power enough to carry a relatively heavy DSLR, as the 5D/7D. The entire structure along with camera, gimbal, motors, battery, etc. we believe will weigh apx. 6kg. We imagine the frame manufactured in carbon fiber, so that it is both light and maintains stability.
The controller is thought to be the Arduino-based platform called 'ArduCopter' (Google Code Archive - Long-term storage for Google Code Project Hosting.)
The purpose of Ardupilot is that it should be easy and accessible to gain control of all input from the gyroscope, accelerometer, gps, etc. as we do not have a lot of experience with these sensors.
All these inputs come from APM2.5 (https://store.diydrones.com/APM_2_5_Kit_p/br-ardupilotmega-06.htm), which should have all the necessary sensors and is easy to connect to a computer, and (hopefully) easy to calibrate.
The engines are thought to be 880kV, which together with its blades should give hexacopter an upthrust at 1200g per engine v. 75% (roughly around 7kg for all six engines). It's all available in this set along with ESC’s, propellers and distributionboard:
http://www.buildyourowndrone.co.uk/HexaCopter-Full-Motor-ESC-Set-880Kv-p/ach-fmk88.htm
Can you possibly see any weaknesses in this setup?
Regarding the camera-gimbal we haven’t completed our research yet, but wish to make it controllable in 3-axis. We are considering using a powerful servo called “Savox SC-1258-TG”, and using http://photoshipone.com/3x-pro-v2/ or http://www.averticalview.com/ as inspiration.
We also bought a 6-channel remote control "Spektrum DX6i" which probably is best served controlling the camera-gimbal.
How many channels do we need to control the hexacopter?
We don't have any idea about which battery to use, do anyone have any idea how to choose this?
Any help would be much appreciated….