Beholder Valkyrie 650 X8 build

[glider]

This will be my third co-axial, the first X8.

The frame was bought second hand for a low price, assembled but unused and only missing one screw! Having a Spy 750 Y6, I wanted a light weight X8. It seems like a strong frame, somewhat more than the Tarot I had, but there really isn't any accessories for it and not very popular; what you see is what you get, and I'm having trouble finding X8 motor mounts for 16mm arms. Quadframe has good strong mounts albeit heavier than my liking, but are out of the 16mm plates. Pitlab has what looks to be really nice boom blocks and plates, but they are in Poland and I'd like to get the thing built before summer


If anyone knows where to get some X8 motor mounts (non-extended preferred) that have generous axial spacing between the props please post a link. I may end up 3d printing a set, but didn't really want to experiment.

Anyway, the frame weighs in at 390g without the OEM motor mounts, 454 with. Trying to keep it under under 2.5kg AUW without camera.
Build list:

Frame- Beholder Valkyrie 650
FC- AUAV-X2 PX4/PIXHAWK http://www.auav.co/product-p/auavx2_5.htm
Motors- KDE 2814XF-515
ESC- Wanted HW Quattro, but not enough room, so will try the ZTW Spyder ST 30A I already have which will fit sideways inside the frame. KDE ESC's won't fit.
GPS- Going to try the RCTimer Neo-M8N.
Frsky x6r
Props- 13" APC SF
Battery- 4s

If all goes well, I'm hoping to have a fast relatively light copter that can still handle a gimbal/camera without much effort.

Have others noticed it is becoming difficult to find high capacity batteries, such as 10A+? I have two MS 10A 10c, but don't care for the voltage drop over 3c; had battery FS trigger in testing on the Spy 750 boat anchor. It definitely is not anywhere near 10c. They may work ok on this copter being lighter, time will tell.

 

[glider]

Well, I can see why this thing isn't very popular. It's light, and when the top/bottom plates and arms are secured, structurally it's pretty darn stiff. That's the good part.

It's supposedly a folding frame. NOT! At first I thought the guy I bought it from assembled it wrong, but it turns out it has a fatal design flaw; the frame mounting block for the arm is such that you must completely remove two screws at each arm to allow folding of the arms. Pictures aren't worth the time. Someone didn't think this through very well.

Since there are no accessories available, you're on your own figuring out how to mount everything. There is no room for a PDB. An additional plate would need to added on the bottom for that because the landing gear is in the way. So it looks like a copper washer will have to do.

Lastly, the battery tray is less than adequate. Apparently they assume a 3200A battery is the largest it will ever have attached. A more robust plate is a must for a big battery, but I'll add some washers and give a try anyway as I want to keep it light as possible.

This project is more for fun that anything. My biggest concern is vibration. If it's excessive, it will end up being a 4 motor test rig for Arducopter firmware.