Hey Guys I am just getting caught up on this feed and looking through it I can throw in a few things. I have built a few 810 and for what I have had with the copter I can say this. Over all its a very good design, if flies great, and to me its a work horse, I have had it up in winds over 25mph, I have had it carry about 3lbs of payload and have not had any issues.
Currently I have 15 inch collapsible props, and with 2 x 5300mah I am getting 16min of safe flight time before needing to land. When it comes to voltages on the batteries, for my T810 the voltage is not an issue if I fly my copter right down to 21 volts under load, its a perfect result for 80% used.
With that said I also have bigger copter, a Tarot x8, and that one is 21 lbs loading at takeoff, when flying if I fly it down to 21 volt under load, when I recharge the battery its only takes in 60% of capacity, I did contact a few battery companies and asked about flying the voltage down to below the 21 volts (or 3.5volts per cell), they told me that if you fly to 3.4 volts that is fine, 3.3 is OK but not advise able, and 3.2 will cause the battery damage. In my case if I fly it down to 3.4 I obtain my 3.7 per cell not under load and it take about 80% of capacity to recharge the battery. All good stuff.
About the flipping two things first is on the first flight video, in a way to me the copter looks like its a little to light for the situation, if that is true unstable landing will happen, and you will see in flight, rock just like it did when you give it an input and let off the sticks, it will get in an over compensating teetering. My guess is if you tie a 3lbs weight on the bottom you will have a different result.
Also the landing gear is long so the higher off the ground it is the more prone to tip some. if you have it a little unstable and you land at a bad angel (it will not take much) then you could have it tip. I also bet if you add weight to it you will have much better landings
Here is a clip of one of my copters and it was to light, I could not figure out what was going other then it may be to light, so after tying a 5lb weight to the bottom the issues went away. The clip show what it look like when its to light.
At the end of the day for my 810 here is a clip of it working when you get it dialed in.
and this is a clip of the copter in flight how nice it will fly.
I know there is a lot here but I hope some may help in the questions .
over all I think its a great design and for a build I find it a very versatile craft.
best Jack
