Hello everyone. I suggest you an instruction on how to build your 250 class racing quadrocopter.

This instruction is for those who wants to self-assemble their racing quad, but does not know what components to choose to start with. Of course I set my personal opinion, and you can change what you think is necessary. If you have a desire, time, money and a bit of skill to work with your hands, you will build your quadrocopter without any problems. Let's begin ...

P.S. this is my first instructable. Looking forward for comments to improve my instruction.

P.S.S. NEVER set up your quad with mounted props!!!

P.S.S.S Sorry for my English :)

Step 1: Parts List

Frame - I recommend to buy ZMR250 frame, it's a popular frame and doesn't cost very much, durable, with a cheap spare parts and a large number of upgrades made on 3D printer. I recommend to buy this frame. This frame is cheap, made of good carbon, with the additional holes and slots for easy placement and fixation of copter components.
Motors - there are a lot of new versions of motors from different vendors, and it is difficult to recommend anything specific. In this building, I use RCX H2206 2250KV motors, it looks nice, but I don't use it before. Important that you can find parts for replacing for these motors, bearings and axes, CCW propeller mount. Also interesting motors Rctimer FR2205-2300KV, Rctimer FR2306-2300KV, SunnySky X2204S-16 2300kV Generation II . You need 4 pcs, but for spare I recomend to buy 5 pcs, same for ESC.
ESC - Use the ESC with BLHeli firmware. In this building, I use Rctimer Mini ESC20A but highly recommend to use a new ESC Racerstar RS20A BLHELI_S, very good ESC with low price.
Flight controller - recommend to use the SP Racing F3 Flight Control like this one or better F3 EVO Flight Controller
Video Transmitter - I recommend to use a 40-channel video transmitter with RACE BAND 200mW. There are many different transmitters, not very expensive and a good example is Eachine TS5840 Upgraded 40CH 5.8G 200mW Transmitter, this one beter FX795T-2
Camera - I use the camera with SONY EFFIO chip in this building, I use one purchased her. But I higly recomend this Foxeer XAT600M HS1177 or Foxeer HS1190 Arrow
PDB - for a clean and easy assembly, I use just this PDB. This is the latest version suitable for SP Racing F3 Flight Control. Just BEC is located directly on the motherboard, it is unnecessary to solder them as in previous versions, it is much better. There is a jumper on, to power the camera and transmitter from 5 or 12 volts. If you don't want to use this PDB, I recommend to buy some board like this.
Batteries - Buy at ones 4S battareis with the highest possible discharge rate C. I use Dinogy 1300mAh 14.8V 4S 65C from here or here Price is changing periodically, choose where cheaper.
Propellers – good props KingKong 5045, cheap and duralable. Now gaining popularity 3 blades props or 10 Pairs Kingkong 5040 5x4x3
Remote control - I use TARANIS X9D Plus + x4r recciver. Excellent control, many people use it. x4r The receiver is small and has an SBUS connection, which is very useful when the space is limited on the smaller models. Bought here.
FPV goggles and receiver - I use Fatshark Dominator V3 with DIY module. Quite an interesting option helmet.
Spacer prinded on 3d printer.
OSD- On-screen display, optional.
Bolts - 16 pcs M3x30
Battery Strap
Polyester Velcro Peel-n-stick
XT60 connector
Heat-shrink tub about 20-22 mm
Led strip (optional)

Step 2: Motors

Let's start with the motors.

Some motors have CW (clockwise) and CCW (counter clockwise) prop shaft threads. The difference is the thread orientation on the prop shaft is the opposite. That means one prop nut can be fastened by rotating clockwise, and the other prop nut needs to be rotated the other direction. They call this ‘Self locking’, because on a quadcopter we have 2 motors spinning CW direction and the other two spinning CCW. As the motors are spinning, the prop nuts automatically tighten themselves and don't come loose.

Lets mount motors on the arms, I recommend to use a thread lock, best middle lock (Blue). (Do not use the red one or you will never be able to undo the screws later)

Be careful when tightening the screws, sometimes the screws take out the wires inside the motor and may cause a short circuit and damage the motor, you can use a plastic or metal washer.

Cut of extra wires, remove the insulation layer from wires and cut of pice of srink tube from ESC, use a flux and solder. Unsolder wires from ESC, and connect wires from motor to ESC.

Use heat srink tube to fix ESC on the arm. Some put the ESC into the frame. I advise you not to do so, ESC is heating during the working and need cooling. There is no colling inside the frame and ESC often burns out.

You can connect wires to all 4 ESC in the same way, and later in BLHeli Suit change the rotation direction for 2 motors.

Step 3: PDB - Power Distribution Board

The new version of PDB is very useful, it has all the necessary connectors for easy installation without a heap of wires.

Let's start.

Solder pinheaders and buzzer from PDB set (very useful when you lost your copter in hight garss).Cut off the extending part of the pin. Solder them, use a flux.

PCB has jumpers to select camera and VTX power supply voltage, 5 and 12 volts. You must short pad (5 or 12 volts) that matchs to your camera and VTX viltage.

Take 16pcs M3x30 bolts, the lower plate of the frame and PDB. And put it all together with the arms. Place correctly CW and CWW motors.

Use 3d printed bumpers to make frame more duralable and protect your PDB from impact.

Solder ESC wires to PDB pads.

Print spacer and bottom XT60 holder.

I was cut XT60 pin, because I need some more space to place VTX. Solder wires to XT60 and then solder to PDB pads.

bamper v5.step
Download

Step 4: Flight Controller

There are two types of FC, acro and deluxe. The deluxe version has an additional barometer and magnetometer. For racing quadrocopters is not necessary functions. Especially if you are not using OSD.

Lets flash Betaflight Firmware to FC.

Go here to download the betaflight firmware hex file for your flight controller

Click on the Firmware you want (for example “betaflight_2.7.1_SPRACINGF3.hex” is for SP Racing)

Click the button labelled “Raw”.Rigth click on anywhere on the webpage, and choose “Save as…” to a location on your computer. (if file name is “betaflight_2.7.1_SPRACINGF3.hex.txt”, just remove “.txt” before click save)

Install Cleanflight Configurator

Plug in your SP Racing with boot pads shorted and open Cleanflight Configurator (if you have autoconnect selected then click disconnect)

Click “Load Firmware Local” and locate the HEX file you saved. (You may have to change the “file type” setting to “all files” in order to find the hex file)

Click “Flash” (you might fail thei first time, just press flash again)

Some basic setup for FC.

Calibrate accelerometer
SETUP failsafe !!!
If you mount FC board in the direction different from that indicated by the arrow, you will need to indicate this in the settings. Go to CLI page and write - SET ALIGN_BOARD_YAW=90 (ARROW POINTING LEFT) press Enter
Write "save" press Enter
Swith on Serial RX on UART3 at the Ports page
At Configuration page select Reciver Mode - RX_SERIAL , Serial Reciver Provider - SBUS

Do not forget to save the settings after the changes

Further adjustment of the flight controller, follow the manufacturer's instructions and watch video instruction. I don't write all the moments, because it's a lot of information that will be enought for an another aditional instruction.

SPRacingF3-Manual-latest.pdf
Download

Step 5: ESC (Electronic Speed Controllers) Setup

Now configure the ESC. With our SP racing controller (as NAZE32) we can customize our ESC simultaneously. To do this, the following conditions are necessary:

Running Betaflight on your FC
Running BLHeli already on your ESC
BLHeli Bootloader installed on ESC also now working with SimonK Bootloader. Firmware and bootloader is not the same thing.
Latest version of BLHeliSuite

Connect the controller to the computer and apply power to the PDB.

Download and run BLHeliSuite.

First of all, in BLHeliSuite, select your interface, with (Cleanflight) at the end of the option.

Don’t worry if you chose the wrong one (whether Atmel or Silabs), you will be warned if you have selected the wrong interface.

Connect and read settings. Once you have chosen the correct interface, and the COM Port of your flight controller, click Connect, then Read Setup.

Flash Latest BLHeli Firmware.

You might see this message saying “Setup not in Sync with Master”. That basically means some of your ESCs have different settings. Settings including PPM Min/Max and PWM Frequency/Damped and so on would trigger this warning. Difference in motor rotation setting would not trigger this warning.

You must configure all ESC the same, but for two CWW motors change the value to reverse rotation.

Once you have programmed all your ESCs, you want to do a finally check. There is a Checkbutton on the bottom right. And below shows to you the All Okay message. And you should see all the ESCs are green. (except ESC 1 is blue, because it’s the master ESC)