I've finished the assembly of my Ultimate 40S, and am now waiting for some good weather for a maiden flight. (It may be a long wait.)

My build was as described by the supplied instructions. For battery installation I cut a hole in the lower half of the firewall and installed a light plywood box that reached back to the wing servo. The three batteries sit on edge and side-by-side in the box and are held in place by foam and velcro. An access hatch in the lower cowl front allows for battery changeing. I discarded the supplied wheels and pants, and installed 3 inch wheels.

AUW 5.5 pounds (a little heavy, but I like fast toys)
Neu 1509/1.5 with 6.7:1 gearbox
CC HV-45 ESC with UBEC
15*10 APC-e prop
CG 3 inches from center leading edge
6S2P 4200 mAh LiPo (three 2S2P 4200's connected in series)
MotoCalc:
44 amps
847 watts in / 755 watts out
131 ounce static thrust
63 mph pitch speed
5:39 run time
2823 ft/min best climb rate

Merry Christmas and a Happy New Year to all, Glover