Update..so, like any true guy, I keep working on this thing because the initial kit I got I found some flaws in. Of course I wind up spending more money on it than I should, but I digress...
Motor mounts coming with the kit are cheap, using brass inserts into plastic that hold the screws. Problem with this is if there is either too much vibration, or you herk down on a screw too hard during construction/re-assembly, that brass inserts separates out from the plastic, creating all kind of havoc.
So I got some replacement, CNC aluminum motor mounts that also have rubber grommets to help with engine vibration. They cost twice as much as the plastic replacment mounts, but I was having to replace those about every third flight, so I'm sure after 6 flights they'll pay for themselves.
The problem is that I'm using 13" props. I was pushing the size of the propellers as they were (clearance between tips was about 1/2" or less). The new motor mounts shorten the length from center of the vehicle to center of the motor shaft by about 1/4". Tips of the props nearly touched. Luckily, I measured those out while installing the new mounts so I didn't fire the thing up before measuring. That would have been a messy (and dangerous) disaster.
Finding the kind of carbon tube these things take is not easy, and especially now I have to custom fit these to extend the tubes out to make the propellers fit. I found tubes in 1200mm lengths and bought two.
The messy part was figuring out how to cut fabric laminated carbon tube. Circ saw doesn't work...so wound up using a grinding wheel on a Dremel to cut. A little time consuming and messy (carbon dust is nasty; my brother did all that wearing a respirator). Essentially, I widened the vehicle from a 680mm - or about 26" in diamter from motor hub to motor hub (hence the model name was Tarot680Pro) to about 800mm - or about 31".
Problem is we had to take the vehicle apart. Lot of parts and fasteners. Plus, while in there we re-wired it (no Tim Allen references please) with a little thicker gauge wire to hopefully reduce voltage drops under load and to get the connectors out of the middle of the tubes. We would have issues when we would need to replace a motor mount that the whole tube would have to come off. No fun and time consuming. This change should eliminate all of that.
With the new configuration, I should be able to turn a slower motor on this with bigger props (looking at going to 14 or even 15 inch props) and get better flight times but would have to change from a 4S battery (which is 14.8V) and go to a 6S battery (22.2V). I could run two 3S batteries in series but that bulks up the undercarriage. I'd also have to buy 6 new motors. More lettuce.
Here's a picture of the hex before the modification:
Here's a picture after..no center cover but you can still see the difference.
Sorry to bore you guys with this.