IMHO - the Tarots look like excellent products. I would personally opt for the 960 MR airframe which is the 810 but with longer motor arms. Those longer motor arms give you more latitude for future, larger prop diameters beyond the basic 15 inch diameter props that you may decide to start out with. Using eCalc I came up with a design for a 800mm MR airframe to carry a Hero GoPro3 c/w 2axis gimbal and the best I could achieve with two 5000 mah batteries was 12.5 minutes according to eCalc results but actually 15 minutes of actual hover flight time. In your case your will have a heavier camera and a heavier gimbal but possibly a lighter MR airframe.
As far as motors, the new pancake motor style which is specifically designed for Multirotors takes advantage of more poles, i.e., 22 poles and higher while also increasing the torque by means of increased motor stator diameters. Motor height is secondary to motor diameter with respect to torque..... and you will need extra torque to turn the larger diameter props to produce the needed thrust. Also the newer paddle type props can be directly mounted to the pancake style motors which helps slightly to minimize motor vibration challenges by keeping the motor shaft length to the prop as short as possible. There are rumours of larger 32 pole MR motors but I haven't seen any for sale yet. In summary if you look closely at ZeroUAV MR products boosting about 60 minute airtimes c/w payloads, it should be obvious that MR frame diameter is needed to allow for much larger but slower props (or you will have to go with a Quad coax design which makes room for larger props but loses some prop efficiency.
Finally keep in mind that it is sometimes possible to build an MR system that your controller cannot be configured to control properly with respect to PID loop tuning for Basic and Attitude gains in which case you could end up with an MR that constantly wobbles during flight. I am currently using the Turnigy Multistar
http://www.hobbyking.com/hobbyking/..._4830_420Kv_22Pole_Multi_Rotor_Outrunner.html but these are 420kv......if I had a choice with pancake style motors I would have selected a 320kv version....... still looking. In the meantime Tarot makes/sells motors that are almost identical to those sold by DJI for their S800 but at a much lower price......and there are others as recently posted here on MRF.
An MR frame manfacturer you might also want to consider is ChaosChoppers in Swift Current Saskatchewan.
http://www.chaoschoppers.com/
Hi I'M planning to build a 6s hex with the tarot 810 or the 960 any advice on most efficient motor would be nice. I'm will be carrying the NEX5r on a brushless gumball, AUW should be around 5Kg and I'm looking for 15 minutes of flight
Rhanks
