1. Design

Quad-copters consist of a frame, motors, FCU or Flight Control Unit, Battery and wiring up of receiver and ESC's. After studying some builds that previous expert flyers had done I had a starting point and went from there. Additionally I found a website that will help you calculate all the variables when designing your Copter:

http://www.ecalc.ch/xcoptercalc_e.htm

So I had originally planned to make my own frame from a kit, but that didn't feel right, it felt too cookie cutter. I read a lot of hackaday and had seen some projects that use items in unique and adventurous ways, so I decided I could hack together my own frame from "Microrax". Extruded Aluminum is stronger than wood and cheaper than a carbonfiber frame, so I built my quad around the idea that I could modularize every item off the RAX.

Simple engineering told me I need to add a top and or bottom plate to add rigidity and a place to attach stuff. I figured since I was using aluminum for the frame, the top and bottom plates needed to be of the same. After an evening of sketching and brainstorming other items for the re-purpose of flying, I found some extra ABS plastic to add to the frame to give strength and as an insulation for the FCU and as a perch for the Receiver

The rest of the parts, Motors, FCU, Battery, ESC's, Transmitter (Tx) and Receiver
(Rx) I ordered per the build that worked on the Ecalc

MultiWii 328P Flight Controller
Turnigy 530kv Brushless Motor
TURNIGY 25amp ESC
Turnigy 4000mah Lipo Pack
OrangeRx T-SIX 2.4GHz DSM2 6CH Transmitter (Mode 2)

The design of a copter really starts at the propelers, large props need a lot of torque and not a lot of RPM's and vice versa. I wanted large props for plenty of lift so I had to go with strong motors. The ESC's or Electronic Speed Controllers convert and adjust the power going from the battery to the motor, they are controlled by the FCU, and it gets the signal from my Rx. So I have a frame for the motors and FCU, I will zip tie the ESC's and wiring to the frame and mount the battery underneath, I mounted the Rx on the top plate above the FCU. Other than a Tx I think that's it for designing a QC. Last thought, there is a lot of other things that are needed to get a Q.C. off the ground, like a battery charger, bullet connectors, a wiring harness, props, and replacement props, and a prop balancer to name a few.