Table of Contents
DJI Flamewheel 450 Special Edition Quad
The DJI Flamewheel multicopter kits are a cheap, robust basis for a PX4-powered quadrotor. As they are very popular, parts and clones are widely and cheaply available.
Parts listed here are suitable for the 450 series quad.
These PX4 autopilot parts are required:
- 1x Pixhawk or FMU + IO Kit (Pixhawk is FMU + IO in one case)
- 1x u-blox GPS module for Pixhawk
- 1x RC Receiver: List of compatible RC receivers
- 1x Radio modem: 3DR radio preferred, List of compatible radio modems
- Multiple 3300 mAh LiPo batteries, suitable for at least 25A/30A discharge. It is best to buy several of the same battery in order to keep the copter weight constant when changing batteries.
Flight tests of DJI ESCs have completed successfully. This means you can also purchase the ARF kits which include frame, DJI ESCs and DJI motors:
Start by mounting the motors and frame arms. The first motor and arm have already been mounted in this image.
The image shows the main parts layed out as they will be soldered in the next step. Solder the ESCs to the main base, red wires on (+) and black wires on (-). Often the wire lengths are excessive, this planning step allows to plan the correct lengths and to cut the wires as needed. The connectors on the lower right ESC are 3 mm bullet connectors, the most common motor connectors used.
The isolation of the wires of the motor controller needs to be cut down slightly more than the default, as shown in the picture.
This is the end result after soldering all connections.
Mount the power distribution board below the already assembled frame parts. As visible on the photo all bullet connectors were insulated with heat shrinking tube before.
CAREFULLY inspect the polarity of your solder joints (black / red). Unmount the propellers, take a fresh battery and go outside the building. Do not lean above the quad and connect the battery, ready to disconnect it any time. The four motors should all beep. The purpose of this test is to make sure that an error in assembly did not lead to a short-circuit or reverse polarity. Performing this test outdoors limits the potential damage to just damage on the quad.
After the electrical test has been successful, fix all wires, BUT make sure to still be able to unplug the bullet connectors (to fix the rotation direction of each motor).
Assemble the Autopilot
Assemble the autopilot as shown on the picture below. Instead of connecting the ESC to it, solder the power cable to the power distribution board (anywhere, e.g. on top of the battery connector).
Connect the Motor Controllers
Each motor controller provides a 5V supply to the RC receiver in a classic RC plane setup. However, these supplies are normally not built to be paralleled. To prevent damage to the motor controller, use a small screw driver or the blade of a cutter to lift the plastic notch of the center pin (red) and pull back the pin. Once the pin is pulled back, tape it to the other wires. This allows to put back the pin later if the setup changes. The connector for motor 1 is next to the white big power connector on the back, and the diagram on the right indicates the right motor assignment.
Connect a battery, make sure to have FMU upgraded. Now with props still unmounted, first press the safety switch long enough so that it starts blinking faster. Now arm by putting the throttle stick in the lower right corner. The motors will spin immediately. Slowly rise the throttle stick until they spin faster. Put the throttle stick into the lower left corner to disarm and compare their rotation direction with the diagram on the right. If the rotation direction is wrong, unplug any of the three bullet connectors on the motor, and re-connect them swapped around - this will change the rotation direction of the motor.
After the rotation directions have been checked (and corrected, if necessary), put the rotors back on, fix them tightly and tighten the zip ties holding the cables.
Special Edition Part List
This is list is shown in the build log
- 4x Brushless outrunner motors: RC Timer HP 2217 (800 Kv) (RC Timer Shop)
EPP1045 propellers in CW/CCW pairs. Buy more than 4 total, as waiting for replacements can be tedious. Avoid carbon fibre propellers as they can be extremely dangerous when handling or tuning your quad. e.g. RCTimer 10x4.7 12-pair multi-pack.