AC4 4k HD 2S sub250g LR quad feat. DJI

By DiAleksi on Mar 08, 2021

36  1,393  10

My new Anti Crime V4 LR quad project's idea is inspired by DJI Mini2 motors and props. I believe that DJI is pretty good in motor-prop optimisation. DJI got 250g drone to fly on 2S for about 30min. I got an idea to build LR FPV drone to be lighter and fly longer than Mini2. So I took its motors and designed a frame around them. The quad has 4K HD recording camera, GPS and Crossfire onboard.
At this moment its AUW is 214g. But I got uncontrollable vibrations on arms. See the Part 1 video of this development:


Even with weight adding quick improvement I got 34min of the flight time! So I have to redesign the arms to be untwistable and clean.
Developing continues. Stay tuned :)

Photos

Part List

Frame

AC4 – a bit different quad
Dima.fi
See Site

Flight Controller

HAKRC F411 20A AIO 26mm Support PWM Multishot Oneshot DSHOT 7g w/barometer for Toothpick FPV Racing RC Drone (2 builds)
Banggood.com
$37.10

Motors

4 x In Stock Original DJI Mini 2 Arms Left Right Front Rear Motor Arm for Dji Mavic Mini 2 Drone Repair Spare Parts Replacement
Aliexpress.com
$63.52

Propellers

DJI Mini 2 Propellers
Store.dji.com
$12.00

FPV Camera

RunCam Split 4 4K High Definition Recording / Low Latency FPV 2 IN 1 FPV Camera 16:9/4:3 NTSC/PAL Switchable For RC Racing Drone
Banggood.com
$82.68

FPV Transmitter

TBS Unify PRO32 NANO 5G8 V1.1
Shop.brickracing.com
$32.90

Antenna

TrueRC OCP 5.8GHz Antenna (short) - U.fl connector RHCP
Shop.brickracing.com
$14.90

Receiver

TBS Crossfire Nano Rx (SE) - FPV LONG RANGE DRONE RECEIVER (412 builds)
Team-blacksheep.com
$29.95

Batteries

2 x 18650 Murata (Sony) VTC6 li-ion akkukenno - Ei suojapiiriä - Flat-top (10 builds)
Akkula.fi
$27.90

3D Printed

Camera mount for 4mm standoffs by DiAleksi
Thingiverse.com
See Site

3D Printed

TBS R9 Immortal antenna holder for 4mm standoffs by DiAleksi
Thingiverse.com
See Site

Hardware

20 PCS M2*20mm M2*23mm M2*25mm Standoff 4mm Outer Diameter for RC Drone FPV Racing Multi Rotor (3 builds)
Banggood.com
$5.93

Misc Parts

Beitian Dual BN-220 GPS GLONASS Antenna Module TTL Level RC Drone Airplane (68 builds)
Banggood.com
$18.99

Misc Parts

ICX301-M AMASS - Plug | DC supply; XT30; male; PIN: 3; for cable; soldered; 15A; 500V | TME - Electronic components
Tme.eu
See Site
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Discussion

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GrayscaleFPV   Apr 30, 2021  

I've built a quad similar to your setup with dji mini 2 motors and props. The props seem to have really TERRIBLE vibration characteristics as you have already experienced. Now i switch to 1404s and HQ T5x3 props and the vibration's gone, no arm reinforcement needed and i still get similar efficiency. the dji motors are lighter though, that's the trade off i guess.

jdmkramer   Apr 07, 2021  

2S Liion is something I want to explore further. I've enjoyed the micro reverb and a few others, but I can never get the tune right across such a wide voltage range it seems. Did you find yourself having to do anything special to avoid wobbles?

jdmkramer   Apr 07, 2021 

Then again, your power combo is already tuned. Perhaps my issues also came from my prop and motor choices.

DiAleksi   Apr 07, 2021 

Yes, power combo is proved on DJI Mini 2, so my problem is in the frame. New arm versions are on the way. Then I'll make new tests.

BaTTaN   Mar 17, 2021  

Nice build DiAleksi! Ive never seen this frame before now and am saddened that it does not look to be available in the US lol could be stl files I'm not seeing though :-( You thinking about loading up INav on something this small and feeding it some missions?? I'm waiting to see someone build a micro mission eater lol

DiAleksi   Mar 17, 2021 

There will be changes in that frame prototype. The final version will be available in Swedish drone shop. I believe they ship to US also.
I use iNav on my wings. But setting it on my 6" quad was pain in the ass. Big problems around the compass position. So this time I think I'll try Ardupilot if I want some missions. But don't think I'll have an interest in that area, as new regulations make all LR fun illegal.

BaTTaN   Mar 17, 2021 
1

Yeah our new FAA policies coming down aren't great either. Cool build again and I'll be keeping an eye out for your frame. Dig the website to man, great work!

BaTTaN   Mar 17, 2021  
phaley51   Mar 15, 2021  
1

Very interesting, I thought about doing something like this with the standard mavic motors, might have to revisit still or do something similar to this. Thanks for sharing, interested to see how it progresses further!

kfncolo   Mar 09, 2021  
1

This is great. I've been thinking the DJI mini motors would be a good place to start. I keep looking to just buy the motors, which they don't seem to sell without the whole arm assembly, but I guess that's not a lot more expensive than a bare motor. Looking forward to your development of this setup.

OptimaZe   Mar 08, 2021  
1

Really cool build! These li-ion builds have me very interested.

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