Birdbrain RC Mahou Shoujo 5

By BirdbrainRC on Apr 17, 2018

27  701  10

Started to make my own frames to suit my own tastes - here's my 2018 race rig.

I'll be completely honest, I'm not the best racing pilot out there. That's a generous way of saying I'm about twice as likely to hit a gate as I am to go through it. My first proper race day in September last year was eye opening - I put my main quad into wet grass in the first heat, and had to fly my (completely different) backup for a few heats whilst I waited for it to dry. Ended up with a broken signal wire too, which required an annoying amount of disassembly to fix.

And so when I decided to start making my own stuff, this was the result. Fully enclosed pod (thank you Smartaudio!), all plastic which keeps the cost down, structured so it can take an absolute hammering whilst protecting all the components including motors. Oh, and it's a stretch plus because I hadn't flown one before and I figured it'd be fun to try.

First build had DYS Storm 2300kV motors, a Racerstar Shot30A ESC, Racekraft 5046TCS props, and no extra cap. Flew great, video was absolutely disgusting. Loads of noise from the ESC, was like flying looking through a set of blinds. In the end a massive hit into a gate removed two of the FETs from the ESC and that was that. Frame was all good though.

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I rebuilt it with a new baseplate with holes for the motor wires underneath to clean up the whole thing, figured out how to swap filaments on the printer and made a tasty blue and orange pod, and for good measure swapped out the DYS motors (one of which apparently has an internal short) for some 2550kV AmaxInno ones, and put in a Racerstar 35A 4 in 1. Because I like to be able to see when I fly, I also added a big 1000μf Panasonic FM cap. Fitting it all in the pod turned out to be fun - in the end I printed a holder for the cap and used the OSD ground pin on the Arrow to ground the video to the Omnibus. No video issues since.

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Anyway, it all looked good so I built a second identical one straight away. This was about 3 days before the first race of the season. Both got a test hover, but the maiden would have to wait until race day. Weight comes in at 356g minus lipo, 535g with a 1300mAh pack.

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Race day was an experience - my flying was horrific, the course was extremely challenging, but the quad was flawless. There were a ton of midair collisions, I crashed out every heat, but nothing broke even as people around me had to swap to backup rigs or crack out the field soldering irons. Ended up in the H final and won it despite some of the sloppiest flying I've ever done.

Put another 10 packs through the prototype the week after and still have yet to break anything despite my best efforts - the backup still hasn't even been maidened yet. I do plan to start to sell the frames later in the year, before that I need to establish how much abuse I have to give one of these before it gives up. Still haven't tuned it yet either - for racing, Betaflight's stock PIDs worked well, there's always room for improvement though.

Oh...and the initial prototypes are using the lowest grade plastic I could get. I recently cut a new baseplate from the strongest plastic I could get, and ordered some Taulman filament for the printer...stay tuned!


Part List


birdbrain-rc (2 builds)
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Flight Controller

Omnibus F4 V6 Flight Controller (5 builds)
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Anniversary Special Edition Racerstar REV35 35A BLheli_S 3-6S 4 In 1 ESC Built-in Current Sensor for RC Drone (112 builds)


4 x Motor 2305-2550KV (2-6S) AMAXinno (3 builds)
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HQProp 5x4.3x3 V1S Durable Polycarbonate PC Props Light Orange (5 builds)
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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)
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Pagoda-2 Omnidirectional Antenna (9 builds)
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FrSky XM Plus EU-LBT 16CH Tiny Receiver with SBUS (15 builds)
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Turnigy Graphene 1300mAh 4S 65C Lipo Pack w/XT60 (112 builds)


Jumper T-Lite 16CH Hall Sensor Gimbals CC2500/JP4IN1 Multi-protocol RF System OpenTX Mode2 Transmitter Support Jumper 915 R900/C (23 builds)


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


FrSky TARANIS X-Lite (Black) (64 builds)
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ORQA FPV.One OLED FPV Goggles (12 builds)


FatShark Dominator HD 2 Hydro-Dipped Urban Cam Grey and White FPV Goggle
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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)
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HD Camera

GoPro HERO5 Session (303 builds)

HD Camera

RunCam 5 Orange 12MP 4:3 145°FOV 56g Ultra-light 4K HD FPV Camera for RC Drone (21 builds)

HD Camera

GoPro Protective Lens (GoPro Official Accessory)
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Misc Parts

Matek FC Vibration Damping M3 Standoff (2 builds)
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Misc Parts


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 (178 builds)

Radio Module


Radio Module

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

Radio Module

FrSky R9M 2019 900MHz RC Transmitter Module w/ Super 8 Antenna (ACCST/ACCESS)Default Title (17 builds)


MultiStar Premium Multirotor Travel Backpack




TrueRC True-MOX 868MHz Antenna
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Mellowme17   Aug 11, 2018  

this is Pretty close to what i am looking for how close to producing these???

dejaybe87   Apr 30, 2018  

Taulman 910 is a great filament to print with. I've used it in all of my quads. Make sure to keep it in a dry box, otherwise it will absorb a ton of moisture and print terribly. Also, when it first comes off the print bed it will feel really stiff, but after about a week it will soften up some due to water absorption.

thegreen4me   Apr 21, 2018  

I would absolutely buy one if there was an option to get just the HDPE part with an stl file for the canopy. It's just that I can print way better than this.

SixxSeven   Apr 19, 2018  

Wow good work! I would definetly buy this.

IvanNik   Apr 17, 2018  

Did you use nylon or nylon carbon filament for bottom plate?
What is the weight or canopy and frame separately?

BirdbrainRC   Apr 18, 2018 

The bottom plate is CNC milled HDPE, pod is TPU. I don't have separate weights, but the total weight of the frame including screws is 114g. So not the lightest, but not too bad either!

IvanNik   Apr 18, 2018 

NICE!! looks very good!

I thought you printed bottom plate as well..

do you have any expectation for crash resistance?

why HDPE and not carbon fiber?

BirdbrainRC   Apr 18, 2018 

I've flown HDPE frames before and know how tough they are, and HDPE has the advantage of being a LOT cheaper - I got a sheet of 5mm CF from China and it cost me £170 for a half metre square. For the same amount of 12mm HDPE from my local plastics company, £19! That was for the cheapest grade, I did pay quite a bit more for high grade stuff (still about 1/3 the price of the carbon though.) So far crash resistance has been great, I even managed to break a gate with it without any damage to the frame! One downside of HDPE though is it's not a hard plastic, so it does get some little cuts from propeller strikes - mine picked up some battle scars from a mid air collision on race day.

CaptainFalcon   Apr 18, 2018  

This is the stuff I come to this site to see! Full custom stuff instead of yet another mainstream frame build, I like it!

kwong   Apr 17, 2018  

my like for the name lol

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