Sub 250 Volador 3.5 o3 4S

By Gerbz on Sep 07, 2024

3  0  0

This is my first fpv drone, I set myself the goal to be able to fly sub 250 with a small battery and to keep the drone working with larger lipo's.

Space contraints:
I will say that if you are thinking about building this, it's not straightforward;
the capacitor doesnt fit between the stack and the o3 so you need to rotate the stack 180 degrees.
The cap doesnt really fit there either so you have to put the cap on extention wires.

Weight constraints:
The weight budget is EXTREMELY limited for this quad, I had to take some pretty drastic measures to come in below 250g:
I used 2 bolts per motor
Almost all tpu parts were removed, only 2 pieces of tpu protection on the front arms are left.
The front 2 standoffs behind the camera cage were removed.
The o3 was flipped because I it allowed me to shorten the cables, it also allowed me to route the antennas along the arms (bad for range, I know)

NOTE: the picture shows 250g but I was able to remove the SBUS wire from the o3 and shorten some other wires so it was 249g when I was done with it.

Flight performance:
Stepping into fpv with a pair of digital dji goggles was amazing but so was the quad, It's powerful enough thanks to the 16mm stator diameter and it's fast! I chased a car going 90-100kph without issues. Flight time is also decent, 3 minutes ish when going full ham and I chased a car at ~30-50kph for ~7 minutes so that's pretty good in my opinion.

Upgrades
I did want to upgrade to an ep1 receiver to not have to worry about the ep2's limited range. This allowed me to remove my custom designed receiver cover which in the end removed like 2 grams of the AUW. I highly recommend this option as I had 2 cases of sketchy rx signal when flying 100+ meters away.

The receiver cover
https://www.printables.com/model/926267-volador-35-elrs-ep2-mount

Photos

Part List

Frame

Volador VX3.5 O3 Freestyle Frame Kit - FlyFishRC
Drone-fpv-racer.com
See Site

Flight Controller

SpeedyBee F405 Mini BLS 35A 20x20 Combo Stack (5 builds)
Rotorvillage.ca
$83.99

Motors

4 x T-Motor P1604 FPV Drone Motor - 3800KV (2 builds)
Pyrodrone.com
$79.60

Propellers

HQProp T3.5x2.5x3 (2CW+2CCW) PC
Drone-fpv-racer.com
See Site

FPV Camera

DJI O3 Air Unit (86 builds)
Pyrodrone.com
$179.00

Antenna

5.8G Whip VTx Dipole 2dBi IPEX U.FL Linear Antenna
Fpvfaster.com.au
See Site

Receiver

HappyModel ExpressLRS EP2 2.4Ghz RX (3 builds)
Rotorvillage.ca
$19.99

Batteries

4S 650mAh 120C GNB LiHV Battery - XT30 By Gaoneng
Drone-fpv-racer.com
See Site

3D Printed

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Printables.com
See Site

Misc Parts

Ummagawd UMMAGRIP Lite - Super Sticky Battery Pad (5 builds)
Rotorvillage.ca
$6.39
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