2Fiddy 3.5"

By granola on Apr 19, 2024

4  0  5

First "sub-250g" build and first with DJI O3!

Chose the 2Fiddy frame since the new version is built to fit the O3, doesn't require additional TPU mounts, and I like the aesthetics. Went with the T-Motor 45A AIO in the hopes that it's quality, and it has the MPU6500 gyro (in addition to the DJI plug). For motors, the 1804s are 1018mm³ in stator volume, which is just about spot on for a 3.5" quad. I'm running the Tracer RX since that's what I've been using for a few years on all my race quads. And Tattu 750mah 4S packs — they're the same weight as the 650 TAttu packs since apparently they're the same packs but with top-grade cells.

Started with Supafly's 3-4" Freestyle preset, adjusted based on his online PID tune calculator. I then did some "basement tuning" with PIDToolbox to dial things in. I backed off the D and Master gains a little bit from the optimal to give a bit more headroom in case of bent props and such. Also adjusted some of the FF jitter/smoothing parameters, dynamic idle, turust linear, etc.

I'm planning to use the O3 footage vs. running any HD camera (and that has largely the impetus for this build). 2.7k 4:3 @ 100Hz is what I'm running right now for minimum latency. This means final flight footage will be 50fps, which isn't ideal — I'd prefer 60fps for better compatability — but the 50fps video seems to play back fine on most displays I've tested with. I'm also using ND filters from Camera Butter, running manual exposure settings, and using the cinelog color and then grading in post.

I added the NewBeeDrone M10Q Micro GPS unit for more confidence flying over water, mountains, and other hard-to-reach areas. Updated to Betaflight 4.5 for the GPS Rescue improvements. Tuned the throttle values based on Blackbox data and set up failsafe to enable angle mode with slightly-above-hover-throttle in Stage 1. I haven't tested failsafe or rescue yet, but I'm getting good GPS lock and data. Note I had to drop down to 4K PID loop and DSHOT300 given the additional processing power that GPS requires (as per the 4.5 setup guide). I left one of the gyro lowpass filters enabled (slider to 2.0) to account for any aliasing with the 8K/4K setup. With 8K and DSHOT600, I was getting a very slow refresh on the OSD, indicating that the CPU was overloaded.

Build Video - https://www.youtube.com/watch?v=3kpWnWUvJDU&t=0s
Frame - https://ummagawd.com/collections/2fiddy-5-frame/products/copy-of-2fiddy-ultra-light-freestyle-frame?variant=39890616615006
Parts Bundle - https://ummagawd.com/products/copy-of-2fiddy-5-inch-build-bundle?variant=40644611768414


Flight Video

Nerdy Stuff
Ummagawd Tuning Video - https://www.youtube.com/watch?v=lLZ4U1I2R8k&t=0s
Rosser Motor Selection - https://www.youtube.com/watch?v=RXy00orSpfU&t=757s
Stator Volume Calculator - https://www.vitroidfpv.com/tools/motors

Part List


Ummagawd 2FIDDY Ultra Light 3.5/4" Freestyle Frame V1.5 (Fits DJI O3)

Flight Controller

T-Motor F7 45A AIO Flight Controller - 25.5x25.5


4 x RCINPOWER GTS V3 1804 3450KV Brushless FPV Drone Motor - Teal Blue/Pink


HQ Prop T3.5X2.5X3 Tri-Blade 3.5" 1.5mm T-Mount Prop Grey (2CW+2CCW) - Poly Carbonate (2 builds)

FPV Camera

DJI O3 Air Unit FPV Camera Module (11 builds)

FPV Transmitter

DJI O3 Air Unit Transmission Module (25 builds)


Team Blacksheep TBS Tracer Nano RX (15 builds)


Tattu R-Line 4s 750mAh 95C Lipo XT30 (2 builds)
See Site


RadioMaster TX16S MKII MAX AG01 Pyrodrone Edition - Carbon Face Plate, Pyro AG01 Gimbals, Blue/Orange CNC parts, Black Leather G (3 builds)


DJI Goggles 2 - Ultra Low Latency 1080p/100FPS 4K/60FPS Digital HD FPV (22 builds)

3D Printed

2fiddy Blank Mount by PinkBatman
See Site


NewBeeDrone M10Q Micro GPS Module with Compass

Misc Parts

Camera Butter ND Filter 2 Pack for DJI O3 Air Unit Camera - ND8/16

Radio Module

TBS Tracer Micro TX - FPV Racing Drone Transmitter (7 builds)

Battery Charger

HOTA D6 Pro 325W 15A 1-6S Dual Channel AC/DC Smart Charger w/ Wireless Cellphone Charging - Choose Your Color (56 builds)

Soldering Iron

TS100 Digital OLED Programmable Interface Mini Soldering Iron (264 builds)
See Site


RDQ All-In-One Driver Tool (4 builds)


RDQ FPV Backpack V3 - Black Stealth (2 builds)


FatStraps 2" FPV Goggle Strap for Fatshark, Walksnail or DJI - Choose Your StyleHD Thin (Snap Loop) / Khaki Mil Spec


NewBeeDrone Max Comfort Goggle Foam for DJI Goggles 2 and Integra
Show stores (6)


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pesterdiligent   23 days ago  

Truly amazing. Your creations are quite unique.
geometry dash lite, from Cadott

BigBeard.fpv   Apr 19, 2024  

how does it fly? do you have any flight footage ?

granola   Apr 19, 2024 

I'll share some flight footage later today!

granola   Apr 19, 2024 

Verdict: flies great! There's some headroom for more tuning, but it's great as-is already. Footage from maiden flight test:

granola   Apr 22, 2024 

And here's the same video but with Gyroflow applied in post:

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