Frog Racer sub-500g

By beeb on Aug 01, 2017

8  842  3

Sub-500g quad for racing, my second ever build.


Weight: 339g without battery. 475-520g with battery.

Pretty happy with this one, the 2400kv RCX motors are beasts, although on the heavy side, and this quad is much faster than my bulky beginner ZMR250. Big up RCX on putting long leads on the motors, wiring to the 4-in-1 ESC was super easy.

I was disappointed that this 4-in-1 ESC doesn't have the very practical connector to wire the 4 signals to the FC, and no built-in BEC. But I had to wire the battery through the FC anyway to benefit from the current and voltage sensors. The pads to connect the battery are very small, both on the ESC and FC, I wish there were bigger because I usually have 12AWG wire on the XT60 and it's super fat. Also a bit disappointed that this FC didn't come with pre-crimped wires and connectors reason being they assume you will wire a lot of components through the connectors on the FC. I had to rely on my old stash of unused connectors to get the smart-audio working and I still haven't found a matching connector for the LEDs plug.

It's a tight fit with the Swift Mini and those aluminum plates. I had to omit one of the screws that hold the adapter to the camera because it was rubbing against the aluminum. Also, the camera connector is very close to the FC at the back and depending on the height of your stack and your camera angle, it might be a problem. It wasn't for me luckily, I lowered my stack as much as possible even though I used anti-vibration standoffs that are quite tall.

The VTX and RX are zip tied to the top plate and they just fit above the stack. The holes at the back of the top plate for the vTX antenna connector are very practical.

Edit: I had to 3d-print a little adapter for the vTX antenna because, when it's mounted on the carbon directly, the outer part of the connector, which is connected to the ground of the whole system, basically grounds the whole frame (carbon is conductive) and this resulted in very bad artifacts in my video feed, wrong colors, as well as a flickering OSD as soon as I armed the quad. After searching for the problem for a while, I noticed this only happened when the canopy (two aluminum plates + carbon top plate) was screwed into the base plate. If I removed the 4 screws, the problem was going away. This led me to believe the problem was electrical, and lo and behold, I found continuity between the aluminum standoffs and any ground pin on the FC, even if the canopy was lifted. So I printed a tiny plate that zip ties into the existing antenna mounting holes, and extends to the back just a tiny bit. This way, the ground of my antenna is not touching the conducting carbon and my frame is isolated from the system. Link to the adapter on Thingiverse

Part List


TransTEC Frog Lite 218mm Carbon Fiber 4mm Arm X Frame DIY Frame Kit RC Drone FPV Racing Multi Rotor (42 builds)

Flight Controller

30.5x30.5mm Betaflight Omnibus F4 Pro V3 Flight Controller Built-in OSD Barometer SD Blackbox (61 builds)


Racerstar Star30 30A Blheli_S 2-5S 4 In 1 Detachable ESC Support Dshot600 Ready for Racing Drone (2 builds)


4 x RCX RS2206 (V3) 2400KV FPV Racing Motor (Japan EZO Bearing / N52SH Arc Magnet) (10 builds)


CA$4.17 2 Pairs Dalprop Cyclone T5046C 5046 5x4.6 CW CCW Propeller for RC Drone RC Parts from Toys Hobbies and Robot on ban (391 builds)

FPV Camera

Runcam Swift Mini 130 Degree 2.5mm FPV Camera Build in OSD PAL/NTSC Orange/Black 22*22mm RC Drone (59 builds)

FPV Transmitter

TBS Unify Pro 5G8 HV (RP-SMA) (83 builds)


Foxeer 5.8 GHz STUBBY RHCP Antenna - Orange (14 builds)


FrSky XSR 2.4GHz 16CH ACCST Receptor S-Bus CPPM Salida Soporta X9D X9E X9DP X12S X Series (15 builds)
See Site


Acehe 4S 14.8V 1300mAh 75C High Rated Lipo Battery (21 builds)


FrSky 2.4G ACCST System Taranis Q X7 16 Channels Transmitter Remote Controller White Battery and Battery Trays Not Include (263 builds)


Fat Shark Dominator HDO FPV Goggles (137 builds)

HD Camera

GoPro Hero7 Black — Waterproof Action Camera with Touch Screen 4K Ultra HD Video 12MP Photos 720p Live Streaming Stabilization (26 builds)

HD Camera

GoPro HERO Session Waterproof HD Action Camera (4 builds)

Video Receiver

ImmersionRC rapidFIRE w/ Analog PLUS Goggle Receiver Module (179 builds)

Radio Module

TBS Crossfire Transmitter

Battery Charger


Lowepro QuadGuard BP X2
Show stores (9)


Sign in to comment

h0lylag   Aug 05, 2017  

I had the exact same problem with the SMA connector conducting into the top plate and frame. Mine was causing one of my ESC's in my 4-1 to desync. I ended up just putting electrical tape down. Definitely not perfect, but its ok.

KWADS_FTW   Aug 01, 2017  

What's the exact weight? I have mine at 498g

beeb   Aug 01, 2017 

Depends on the exact battery, between 475 and 520g!

Guides & Reviews

Jun 21, 2021

AirbladeUAV has done it again and this time they've brought long range to the 5" class! Based on the popular Transformer Mini, the new Transformer 5" Ultralight adopts a lot of the same design philosophies with larger props and more payload capacity. It can fly upwards of 20 minutes on a 4 cell Li-Ion battery pack and in ideal conditions it's got a range of over 4 to 5 miles. In this guide I'll walk..

Read more
Mar 04, 2021

With the release of the DJI FPV Drone cinematic FPV has become a lot more accessible, but you certainly don't want to crash a $750 drone! The QAV-CINE Freybott is a compact, lightweight cinematic FPV drone that can take a hit and keep going. It's a lot safer to fly indoors and around people. With a naked GoPro or the SMO 4k you can capture some great stabilized footage. In this guide I'll show you..

Read more