Birdbrain RC Polaris 5.5 "Snow Angel"

By BirdbrainRC on Oct 15, 2018

20  519  9

After flying the Mahou Shoujo prototypes for the best part of a year, I've come to love how they handle - they just feel really well balanced, clean and crisp on every axis even with stock PIDs. With the weather turning poor I decided to design one last frame before letting the CNC hibernate for the winter, and eventually decided to follow the Mahou Shoujo template, albeit with a more freestyle focus. This the result - the Polaris 5.5.


I started out with the Mahou Shoujo baseplate layout, then stretched it slightly in each direction to allow for bigger props, and a larger pod to give more room for electronics. The baseplate is a little beefier all round and has extra bracing to deal with freestyle abuse.

The pod has a fixed mount for a full size FPV cam with "GoPro style" 2.5mm lens. I thought I'd left loads of room for the stack, but in a genius move I'd checked clearance at the back but not the sides - the tapered sides of the pod look lovely but also leave very little clearance at the back corners with full size boards!


Most of the components are personal favourites - Omnibus F4 V5, Racerstar REV35A 4-in-1 ESC, and AMAXinno motors. Did up from 2305s to 2307s for this build though, with the extra weight and bigger props I figured the extra grunt wouldn't come in wrong. Whilst I was at it I decided to make the build long range ready, so it got an R9 Slim+ and I decided to cram in a HGLRC M8N GPS I had lying around from another project. Surprisingly it wasn't too bad a build once I got the ESC board low enough, even had room for soft mounts for the Omnibus. I did end up making a little G10 plate to hold the M8N and R9 in the stack and make it a bit neater.


Whilst this particular build hasn't flown yet, I put together a more conventional twin first (difference being no GPS and an XM+ rather than R9 Slim+) - took it to a woodland session with the local crew and it flew great, but still have yet to really see what it can do though. Tight and twisty flying isn't what it's designed for, high speed freestyle and carving smooth lines down mountains is more its true intention. Hopefully this winter I'll get the chance to really put the prototypes through their paces and get some quality footage out of it too!


Part List

Flight Controller

Airbot Omnibus F4 V5 Flight Controller
See Site


Anniversary Special Edition Racerstar REV35 35A BLheli_S 3-6S 4 In 1 ESC Built-in Current Sensor for RC Drone (116 builds)


4 x Motor 2307-2500KV (2-6S) AMAXinno (2 builds)
See Site


DAL T5544C Cyclone Propellers - Crystal Purple (2 builds)
See Site

FPV Camera

FOXEER Arrow V3 2.5mm 600TVL 4:3 HAD II CCD PAL/NTSC IR Block Mini FPV Camera Built-in OSD MIC (131 builds)

FPV Transmitter

ChaosFPV VTX[T] Video Transmitter (25-800mW, 7-24V, BetaFlight Telemetry) (8 builds)
See Site


Antenna Pro Pagoda 2.1 Long goggles edition (5 builds)


FrSky R9 Slim+ 868MHz Mini Receiver
See Site


Turnigy Graphene 2200mAh 5S1P 45C Lipo Battery (8 builds)


Jumper T-Lite 16CH Hall Sensor Gimbals CC2500/JP4IN1 Multi-protocol RF System OpenTX Mode2 Transmitter Support Jumper 915 R900/C (21 builds)


FrSky Taranis Q X7S Radio w/ Upgraded M7 Hall Sensor Gimbals (Carbon Fiber) (25 builds)


FrSky TARANIS X-Lite (Black) (64 builds)
See Site


ORQA FPV.One OLED FPV Goggles (12 builds)


FatShark Dominator HD 2 Hydro-Dipped Urban Cam Grey and White FPV Goggle
See Site

HD Camera

Hawkeye Firefly 6S 4K WiFi Sport HD DV Camera - $75.31 |

HD Camera

HawKeye Firefly Q6 4K 120 Degree Angle Action Camera - $59.14 | (2 builds)

HD Camera

GoPro HERO6 Black - Waterproof Digital Action Camera for Travel with Touch Screen 4K HD Video 12MP Photos (5 builds)
See Site

HD Camera

GoPro HERO5 Session (300 builds)

HD Camera

RunCam 5 Orange 12MP 4:3 145°FOV 56g Ultra-light 4K HD FPV Camera for RC Drone (18 builds)

HD Camera

GoPro Protective Lens (GoPro Official Accessory)
See Site


Matek System 4 PCS M2*5+4 M2 Rubber Vibration Damping Fixing Screws for RC Drone Flight Controller (7 builds)

Misc Parts

HGLRC Tiny GPS and GLONASS Receiver Module For iNAV (4 builds)
See Site

Video Receiver

Furious True-D V3.5 Diversity Receiver System Firmware 3.8A (FatShark Attitude Version)SKU: FPV-RX-TRUD3.8A (27 builds)

Video Receiver

ImmersionRC RapidFIRE w/ Analog PLUS Goggle FPV Receiver Diversity Module (179 builds)

Radio Module


Radio Module

Frsky R9M Lite - Radio Transmitter Module (Black) (11 builds)

Radio Module

FrSky R9M 2019 915MHz RC Transmitter Module w/ Super 8 Antenna (ACCST/ACCESS)Default Title (17 builds)


MultiStar Premium Multirotor Travel Backpack




TrueRC True-MOX 868MHz Antenna
See Site
Show stores (14)


Sign in to comment

d3c0de   Jan 17, 2019  

Love the build, but honestly my first thought was how much this looks like an attachment for a blender. "Hey guys let's rip some packs and then I'll make some smoothies!"

Jodie Froster   Oct 15, 2018  

Looks fantastic! I would love to bash it around to see how tough it is, looks like great reinforcements to the exterior (all the "spokes"). This looks like a great chapter in this project. I liked the last one, and I like this one too. How do your vTx's hold up to the heat fully enclosed like that? How many milliwatts can you run before they start to destroy things?

BirdbrainRC   Oct 18, 2018 

Well, it turns out even though the previous plus had next to ventilation and was fine, having absolutely no ventilation is a step too far! Test flights on the beater rig ended in overheating the stack, MCU temp warnings and reboots (of the 4-in-1 I think). Printed a new vented pod last night (bit rough but it's functional, got a nicer one going for the white long range build now). Onwards and upwards!

Jodie Froster   Oct 20, 2018 

I dig the black/grey/pink. I can't seethem, but I want you to use gold motor bolts for style

TeamWolfFPV   Oct 15, 2018  

Sweet slick setup, love everything being totally enclosed! Are the plans available to print? How heavy is the frame?

BirdbrainRC   Oct 15, 2018 

Thanks! It's not a light frame (personally I like the feel of a heavier quad so it suits my flying) - comes in around 130g for the baseplate and pod. As for the files, well, I'm planning on starting to sell my frames later in the year, so whilst some stuff might get released (accessories like session mounts etc) the majority won't be. Also, neglected to mention in the description, but it's not a 100% 3D printed frame either - the baseplate is milled out of 12mm UHMWPE on a CNC machine for strength :)

Jodie Froster   Oct 15, 2018 

I was wondering how the baseplate was so texture free, but still had spots that hadn't been "cleaned up"

Showusflight   Oct 15, 2018  

Any flight videos?

BirdbrainRC   Oct 15, 2018 

Weather here has been shocking for the past week, looks like Wednesday after work is good for a maiden though :) I'll update the build once I have something to show!

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