BETAFPV X-Knight 200mm Toothpick 5" w/ Caddx 4K Tarsier

By wrong17 on Mar 05, 2020

22  967  0

I end up getting a 20a AIO Whoop board that I did not use, so my buddy suggests building a 5” quad with a BetaFPV X Knight frame. Since I record every flight I make, and I hate the quality of the DVR footage and carrying a GoPro defeats the purpose of a lightweight quad. I thought a Caddx Tarsier would be a good compromise.

My motor choice is based on what I have on hand. I have a few choices to choose from, but I will start with the TMotor F30 2800kv (1806 size motors). I am a bit worried about the high KV on these motors, so I hope it does not draw too much amps. If those motors do not work out, I will use try some DYS BE1806 2300kv motors. And my last resort will be DYS SE2205 2300kv motor which I am trying to avoid because it 30g per motor. Where as the F30 motors are 20g and the DYS BE1806 motors are 23g.

The next problem I encounter is how to mount the BetaFPV Tarsier 4K canopy on the frame because none the holes line up to anything. I am not good at 3D modeling, but I manage to create an adapter and 3D printed in TPU.

As for the frame, I really like how you and truly remove 2 screws to replace an arm. The FC is on a plate that is on top of the arms so none of the mounting screws interferes with the arms. For being a toothpick frame the arms seem stiff and comparable to a Floss v2 in terms of amount of flex across the arms. The edges on the carbon fiber is clean but sharp, so I ran a file over it to smoothen it out a bit. I like how they have slots on the bottom plate for you to use a battery strap. But I did not use it because I wanted to save some weight and went with a rubber band instead (Warning, the battery will eject if you crash when using a rubber band).

During the maiden flight the HQ S4 3 blade props did not well. I was a bit surprised because this setup was similar to the Floss v1 that I built in the past. I notice most people are using bi-blade props with 5” toothpick frames so I thought it would not hurt to give it a try. Of all the props I tried so far, the Master Airscrew 5X.4.5 Bi-Blade seems to perform the best. But I need to do more testing before I can really be sure.

After reviewing my DVR flight footage, I noticed the throttle percentage is way too low. The quad will start hovering around 13% throttle and usually do not go more that 30%. So, it seems to me I that can benefit more with a lower KV motor.

So, stay tuned to see what happens when I switch to a different motor.

March 06, 2020 - New Motors
I just finished installing the DYS BE1806 2300KV Motors! And with a doubt the 1806 2300kv motor is a better choice for me. With a 2 blade props I can get 6 – 7 minutes of flight time (that time is based on my flying style). But I am not really a fan of 2 blade props because it does not see to have the same bit at a 3 blade. So, I decided to try the HQ S4 Tri-Blade props again with these new motors and OMG…. This setup is now worth keeping.

I am currently using stock Betaflight 4.0.6 PIDs and Rates and I could always fine tune it later. Even with the stock setup it flew pretty well.


Part List


BETAFPV X-Knight Carbon Fiber Frame Kit (3 builds)

Flight Controller

BetaFPV Toothpick F4 V2 2-4S AIO Whoop Flight Controller w/ 20A 4in1 ESC - XT30 (24 builds)


4 x DYS BX1806 2300KV Race Edition Motors CW CCW (2 builds)


HQProp Ethix S4 Lemon Lime Props (Set of 4)

FPV Camera

Caddx Tarsier V2 4K Dual Lens FPV Camera w/ WiFi (46 builds)

FPV Transmitter

TBS Unify Pro Nano 5G8 (93 builds)


Team BlackSheep TBS Crossfire Immortal T Antenna - Heli-Nation (27 builds)


TBS Crossfire Nano Rx (703 builds)


Tattu 850mAh 14.8V 75C 4S1P Lipo Battery Pack (XT30) (34 builds)


Team BlackSheep TBS TANGO 2 PRO RC RADIO (22 builds)


DJI Digital HD FPV Goggles (86 builds)

3D Printed

BETAFPV X-Knight 4K Canopy Adapter Caddx Tarsier by wrong17
See Site

HD Camera

GoPro HERO8 Black - Waterproof Action Camera with Touch Screen 4K Ultra HD Video 12MP Photos 1080p Live Streaming Stabilization (14 builds)

HD Camera

Insta360 GO Stabilized Camera FlowState Stabilization Mount Anywhere Hands Free Auto Edit Water Resistant Slow-mo Sport Action V (2 builds)

Video Receiver

ImmersionRC rapidFIRE w/ Analog PLUS Goggle Receiver Module (145 builds)

Battery Charger

HOTA D6 PRO Charger AC200W DC650W 15A (6 builds)

Soldering Iron

TS100 Portable Programmable Smart Soldering Iron (171 builds)


Lowepro QuadGuard BP X3 - Drone Backpack for 4 FPV Quad Racing Drones and 15" Laptop w/Exterior Mounts (Black)


BoYz analog bay v2 for DJI FPV goggles


Analog FPV FatShark Module Adapter V2 for DJI Digital FPV Goggles


FuriousFPV Smart Power Case V2
See Site
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