Wazowski

Wazowski - Ultra light weight racing drone (Summer 2017)

Hi, my name is Wazaoski.

  Wazowski is a race quadcopter I built during my free time while interning at Hyundai on Summer 2017. Its name was inspired by little green monster Mike Wazowski from Monsters Inc./Monsters University. The quadcopter's large camera lens and skinny arms resembled Mike's single-eye and skinny arms and legs. And I don't think I'll get sued for making/naming a drone after the character. Good.

See the resemblance? (picture from disney wiki source)

Goal of this project:

• build a sub 250 gram FPV racing quadcopter
• improve all flaws from previously made drone, MarKus
• thrust to weight ratio of 10 : 1
• use 4 cell lipo battery as a main power source
• minimalistic design

Parts I used for this build:

Frame	RFX185
Motors	Racerstar BR2205 2600KV
ESC	Racerstar RS30*4 -> Racerstar REV35
Flight Controller	Lux 32-bit Processor
Receiver	Frsky XM+
Beeper	Super Loud 5V active alarm beeper 9*5.5mm
Camera	Runcam Swift 2
Video Transmitter	Eachine VTX03
Battery	Infinity 4cell 1500mah 70C
Propeller	DAL T5045 V2 -> Racerstar S5048
Connector	XT60U

Pre-assembled to check fittings

  I decided to take out the carbon fiber frame part that makes a square at the perimeter since it doesn't offer much protection and would add weight & air resistance. Any area under the spinning propellers will block the thrust so keeping that area to minimum is important.

bottom section of the frame assembled

  All motors are soft mounted. That is, I put two layers of double sided foam tape between the frame and the motors. Also, notice there are 4 vibration damping standoffs that will be holing all the electrical components including the flight controller above. The only actively moving component of the quadcopter are the motors spinning and these are the source of all vibrations (assuming the props are balanced) These efforts are to minimize vibrations transferred to the flight controller and this would give cleaner, more stable flight characteristics.

With the flight controller added, Wazaoski is ready to fly for line of sight applications

  Although I won't be using the two bladed propellers after completion, they are attached for the testing stage above since they are so cheap and I just have too many of them just laying around.

Adding the FPV features

I am using Eachine VTX03 video transmitter on this build. Unlike many other racing drones that used clover leaf antenna, this one comes with integrated dipole antenna. It may not give video as clean as the cloverleaf antennas but the weight difference is huge. Eachine VTX03 weighs only 3 grams total including the antenna! And is super cheap too.

now ready for fpv flight testings

It looks much better with the 3 bladed props

  After the testing is complete, I changed the propellers to more powerful, more responsive DAL T5045 V2 and the flight characteristics improved significantly.

Swapped the propellers with cooler looking ones

  The original propellers (DAL T5045 V2) seemed too heavy for the motor to handle (5.5 grams each). So I switched the props to Racerstar S5048 that weighs 4.3 grams each. I couldn't really notice the difference in flight characteristics after the change but the quad looks cooler with the new boomerang resembling blades so I am satisfied.

Rear view. I can check and change the video frequency with ease this way.

close up front view

  All the wires are cut to slightly more than minimum required length. This is to minimize weight and save the electrical components from the deformation of frame due to crash. Remember, every gram counts! Also, it looks clean overall.

left side view

  Beeper is attached so that whenever I crash land this quad and cannot find it, I can activate this beeper to locate where the quad is hidden.

  The video clip above is my tryout for 2018 Collegiate Drone Racing National Championship which will be hosted by Purdue University. I had to record the fastest continuous 3 complete labs of the course and they start at the beginning of 00:53 and end at 01:24 (based on the OSD time lapse at the bottom right corner) so about 32 seconds total. Not sure if I'll be going to Purdue for racing event but I will update this in the future.

  The build was a success. All the improvement I wanted to make from my previous drone build (MarKus) has been done and the flight performance was a night and day difference. Wazowski was just way more agile, quick, powerful, stable and light in comparison. The only downside was that since the arms are very thin and due to minimalistic design, the drone would suffer downtime almost whenever it got involved in heavy crash landings. Frame arms gets broken easily and I had to change the 4-in-one ESC after breaking one of the solder pads clean off from the board.

Improvements for the future build would be:

• thicker, more robust frame arms
• aerodynamic canopy
• stretched-X frame
• strengthen vulnerable solder joints (thermally conductive/electrically insulating epoxy)
• smart audio VTX (change power output/frequency from OSD, transmitter)
• betaflight OSD (this has multiple feature including current sensor, crosshair, and many more)