This is the 3rd revision in the "Wizard Killer" series of builds based on the Martian II frame. The original Wizard Killer was my response to the successful Eachine Wizard RTF quad. The Mark III supersedes the more budget oriented Wizard Killer Mark II and is the most featured packed, simple to build and powerful of the three. The base weight with props is about 326g and fully loaded with a battery and Legend 3 it's nearly 600g.

Here are a few of the improvements over the previous versions:

Supports 20mm standoffs

CMOS WDR 2.1mm camera with OSD config

Current sensor for OSD

OSD VTX controls and pit mode

More powerful DYS Samguk motors

Very simple to build

Not to mention a few other useful features:

OSD tuning

Dynamic filters

Flip over on crash

ESC beeper

Frame Assembly

While the frame assembly is fairly straightforward there are a few tricks I've learned to make the process go smoother.

Start with the bottom plate and loosely fit a single screw down through the small carbon plate and through the inner and outer screws of each arm. Loosely attach a nut to the bottom of each screw to keep the arms in place. You want a little wiggle room. The screw holes of the 4th arm may not line up quite right, so you may need to use a hex driver to screw through the carbon. It's a tight fit. Once all the arms have been fit into place send the same type of metal screw up through the middle holes and cap them with the included nylon standoffs. Tighten everything.

This process can be somewhat frustrating as there's virtually no tolerance between the arms. They fit together quite tight and sometimes the holes don't line up quite right. Fortunately this makes for a very solid build that's much less likely to break in a crash.





Motors

Now you can slide the flight controller onto the standoffs and screw the motors onto the arms with blue Loctite. I like to rotate the flight controller to set the power tab off to the side rather than the back. This does require adjusting the yaw rotation in Betaflight later, but it makes for a much more tidy build and a more accessible USB port. I used Battle Cord to protect the wires, but this is entirely optional. I cut 7cm lengths of rope, removed the nylon strands and melted the ends to avoid fraying. You'll also need some shrink tubing to cover the ends.

To solder the wires to the board it's a good idea to flux each tab first and add a ball of solder. To attach the motor wires it's easiest to start from the rightmost tab and work your way left. That way the previous wire won't get in the way of your tweezers. Of course if you're left handed you can start from the left. Cut each wire to size, one at a time, to ensure you don't cut any too short.

Camera, Video Transmitter and RX



To use 20mm standoffs you can use the linked TPU camera mounts, but if you've got a TPU-capable 3D printer you can print them yourself. The Thingiverse page is also linked below. First screw the TPU mounts onto the camera then bend them over the standoffs to situate the camera. The Caddx F1 comes with two wires. I chose to use the wire with the OSD connector to make camera adjustments an option later. I also sleeved the wires with more Battle Cord, but this is again entirely optional. Refer to the photos for wire placement.

To wire the VTX it's a good idea to remove the 5v output and the second ground from the wire harness as we won't be using those. This VTX says it requires 7V, but it seems to work just fine running on 5V. There is always the potential for a brownout running at a lower input, so if you are concerned you can wire this directly to the rings around the main power leads.

Now you'll want to add an XT60 to the power tab. The frame kit expects you to solder the XT60 directly to the tab, but it's much safer to add some 14AWG wire between the XT60 and the tab. This will better protect the tab from breakage and increase the height of the XT60 for shorter battery leads. To do this first solder about 1.5cm of wire to the XT60, add shrink tube and then solder the wires into the holes while the quad is upside down. You can also add a capacitor as it greatly helps reduce noise to the gyro and creates a much cleaner electrical environment for all of the components. You can solder a pair of motor wire trimmings onto the capacitor and slide them under the flight controller from behind. Solder them directly under the main power tab. Be sure to match the polarity.

If you're using the XM+ the RX is very straightforward to attach. You simply add wire between each of the Sbus, 5v and Gnd pads. If you're using an R-XSR or S.Port capable receiver and you want to use telemetry it is possible to use the LED pad as a 3rd UART for the VTX controls. It does require some CLI resource commands, so please search this RCGroups thread for further details. Considering this build does OSD I don't think a telemetry receiver is necessary. If you are using an IBUS or Spektrum receiver you can still use the Sbus pad and un-invert the signal via the CLI using the set sbus_inversion = off command. Please note that this board does not have a 3.3v regulator, so if you are a Spektrum user you will need something like this to power your receiver.

At this point you'll need to apply power using a lipo battery to bind your receiver. It's always a good idea to test for continuity between each of your solders to ensure you didn't create any accidental bridges. Make sure you don't have any props on and apply power while holding the receiver bind button. Once you've successfully bound to your transmitter you can slide the receiver under the flight controller and add shrink tube to the receiver itself. To secure the antennas add zip-ties to the front arms pointed back toward the read motors. Add shrink tube to sling the antenna wires under the zip-ties to protect them from prop strikes.

Final Touches

Now you can finish adding the standoffs and mount the VTX. Flip the VTX upside down and use some foam tape to attach it to the underside of the top plate in a way that the antenna can protrude through the circular hole in the back. Add a zip-tie to parallel the antenna and use some shrink tube to affix the antenna to the zip-tie to keep it rigid and protected. Attach the top plate and add a non-slip battery pad and your assembly is complete!

Betaflight Configuration

Betaflight Configurator is now available as an executable here as well as the BLHeli Configurator. This is a change in light of a move away from Google Chrome extensions. Download both programs and plug your flight controller into your computer to begin.

Go to the Firmware Flasher and choose "Omnibus" as well as the latest stable release of Betaflight. Click "Load Firmware [Online]" and then "Flash Firmware" to update your flight controller. Once complete, click "Connect" On the Ports tab Set the UART1 Peripherals to "IRC Tramp".

On UART3 click Serial RX for your receiver. On the Configuration tab Under ESC/Motor Features select DSHOT600

If want to fly "props out" with reversed motors, select "Motor direction is reversed" below the illustration. (This is optional)

Under Board and Sensor Alignment set Yaw Degrees to 90 to address the rotated flight controller.

Under Receiver choose your receiver mode. For the XM+ choose "Serial-based receiver" and "SBUS"

Under Other Features enable: Airmode, OSD, Anti Gravity and Dynamic Filter

Click Save and Reboot Go to the CLI tab and enter the following commands to place the motors in the proper positions and enable the DShot ESC beacon:

resource MOTOR 1 B09 resource MOTOR 2 A02 resource MOTOR 3 B08 resource MOTOR 4 A03 set beeper_dshot_beacon_tone = 2 save

To complete the remaining steps you'll need to apply lipo power to your build:

On the Receiver tab ensure your pitch, roll, throttle and yaw are being applied correctly. Adjust your transmitter and Channel Map as needed. On the Modes tab Assign an Aux switch to arm and disarm your quad.

Assign another Aux switch to enable Horizon or Angle mode if you need them.

Assign the Beeper and "Flip over after crash" to a 3rd and/or 4th switch. I like to assign them both to a single 3 point toggle switch. On the Motors tab enable the motor test and apply a small amount power to check the rotation of each motor. Take note of any that need to be reversed. Disconnect from Betaflight Configurator and open BLHeli Configurator Flash all ESCs to the latest firmware release.

Reverse the motor direction of any motors that need it.

Save and reconnect to Betaflight Configurator to test the motor directions. On the OSD tab Uncheck all of the features you do not want and arrange your OSD as desired.

And that's it! The default Failsafe settings are generally fine, but make sure they work by arming your quad, applying a small amount of throttle and turning off your transmitter. It should shut down after 4 seconds.

Final Thoughts

This was, by far, the easiest build I've done. It requires a minimal amount of soldering and the short standoffs really give it a nice, low profile look. I love the way it turned out! This is a proven frame and should take some heavy hits. You don't need to use the countersunk washers, but I think they add a nice touch. These motors were just released so the durability has yet to be seen, but they've proven themselves in the power department. This build was courtesy of Banggood.com, and all the parts were selected by me.



