Mini H-Quad Build

For my first real foray into the (surprisingly) deep world of RC, I decided to build a mini quadcopter that would be small, light, and durable enough that it could survive the inevitable crashes that will be part of my learning process.

The build was mostly based around THIS FRAME and the components specified for it, but due to many reports of the frame being very fragile, I decided to 3D print a frame out of much more rigid ABS. This would mean a heavier frame, and more wiring, but I felt up to the challenge of keeping the wiring clean, and as a trainer, the slightly shorter battery life wouldn't really be a problem.

Final Parts List:
(1) 3D printed H-Quad frame - free
(1) Hobby King Multi-Rotor Control Board V3.0 - $16.99 each
(4) Turnigy 1811 2900kV Outrunner Brushless Motors - $10.42 each
(4) Turnigy Plush 6A ESC - $7.65 each
(2) Turnigy nano-tech 2S 850mAh LiPo Battery - $6.00 each
(1) Bag 5030 Propellers (Red) - $3.49 each
(1) Bag 5030 Propellers (Black) - $3.49 each
(1) USBAsp Programmer for Control Board - borrowed, but new ones are around $8
(1) Turnigy 6X FHSS Transmitter and Receiver (Mode 2) - $29.99
(1) Misc M2/M2.5 hardware - free/cheap
(1) Misc velcro - free/cheap

Total Price = $138 + shipping.

The price is pretty low, as I borrowed a number of things from friends who are into RC already such as the programmer and a battery charger. I have already outgrown the transmitter, and if I could do it again, I would have spent a little more money up front for a module based radio with more features and receiver options.

The frame was printed on a Makerbot Replicator 2X using black ABS at 0.2 mm resolution, with a 10% infill. It was printed in two halves, as the build platform was not large enough to print it in one piece. The pieces were bonded together with acetone, which works wonderfully as a solvent on ABS.

Once the frame was together, I tapped the holes for the motor mounts to accept M2 bolts, and drilled out the holes to mount the controller board. I installed M2.5 blind nuts on the holes mounting the flight controller. Next, I removed the ESC's heat shrink, hot glued them into place, and the installed the motors. The motors wires were trimmed, and then soldered to the ESC's. I removed the factory power and signal lines from the ESC's and soldered on my own that were cut and crimped to length. This let me save wire weight, and have a much cleaner build than if I left the wires the stock length. After not finding anywhere attractive to place the receiver, I removed it from it's case and hard wired it to the bottom of the controller board. I installed the controller board, and uploaded the x-coper firmware.

On powerup, two of the motors directions were reversed. Correcting this was as simple as swapping two of the wires on the ESC's. After correcting motor directions, I check the gyro compensations were correct, and then installed the props and took it for it's maiden flight!

Which I immediately crashed.

Luckily, no harm was done, and weeks later, the only serious damage I have done is break a couple props. One of the motors pulled out of its mounting threads, as the plastic wasn't strong enough. A little CA and some zip ties fixed that right up, but I should probably drill the mounting holes all the way through and install nuts the on the backside instead of relying on plastic threads.

Feel free to ask questions, and happy flying!