AOS 3.5 v2 - Caddx/Walksnail

By McLogo76 on Oct 08, 2022

8  1,146  6

After seeing the Chris Rosser Video about the AOS-RC 3.5 v2 i wanted to try to build one with the1504 motors and Avan Scimitar props.
Unfortunately the mentioned Xing 1504 were sold out everywere but luckily I was able get a set of 1504.5 3850kv Brotherhobby motors.
The frame is vom CNCdrones and in hindsight I should have ordered a kit with some spares as it's actually a bit a hassle to get parts sent.

I was told that the Walksnail 25x25 would fit nicely paired with a 20x20 stack or maybe on top of a 25x25 AIO. But to be honet the space inbetween is very limited and the ESC of a 20x20 stack can easily be to broad if the ESC and it's pads are a bit larger like many are currently. I had already ordered the F722 MK4 mamba mini stack and it seemed to fit but the cables were just squeezed too much wich certainly doesn't help. So I just took a doublesided rubbertape and mounted the VTX to be bottom plate wich gives me about 2mm more space between the stack and VTX.

For the antennas I also designed and 3d printed a couple of mounts at the back but is never was really happy with them being a bit near to the props and maybe also cause some resonance on this Chris Rosser frame that I want to build clean. With a Vista kit this is surely easier as you only have one antenna and a couple of options to just zip tie the antenna to the arms as recommended.
I found a solution with TrueRC carbon Matchsticks zip tied to the standoffs that should hold them tight.

This is not yet finalized as I want to make the USB port of the FC easily accessible but I don't wnat to turn the full stack - just the FC... so I will search for a longer cable to be able turn the FC 90°. Btw. you can get rid of around 8grams of weight bei de-casing the Walksnail VTX but I didn't do it on this build yet as it's fixed with double sided tape and not stack screws.

Otherwise the quad flies very good with the standard BF4.3 tune and rpm filtering. The only thing I had to do was going down with the rampup of the ESC as I had desyncs above 70% throttle.

Update //
I've changed to HQ Props 3.5x2x3 as they give me a much better throttle handling and I can use the 100% throttle range with pitch 2 instead of 2.8 of the Advan. Also the Advan tend to break very easily specially if it's a bit colder.

I also did add a Runcam Thumb Pro 4K and the props handle the additional weight perfectly - still feels very nimble and fun to fly.

You can find the 3D parts I designed for the build here:
3D parts for the Runcam Thumb Pro (or similar cams):


Part List


AOS 3.5 v2 (14 builds)

Flight Controller



4 x BrotherHobby VY 1504.5 3950Kv Micro MotorDefault Title (8 builds)


AVAN Scimitar 3.5" Prop


HQ Prop T3.5x2x3 Tri-Blade 3.5" Prop 4 Pack (1.5mm Shaft) - Grey (5 builds)

FPV Transmitter

AVATAR HD Kit (14cm cable) (2 builds)


Matchstick 5.8 – Carbon - TrueRC Canada (2 builds)


RadioMaster RP1 V2 ELRS 2.4GHz Nano Receiver w/ UFL Antenna (24 builds)


Tattu 14.8V 4S 650mAh 75C LiPo Micro Battery - XT30 (26 builds)
Show stores (7)


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toni903   Feb 02, 2023  

What flight time do you get and with what battery? How do you like the power will all up weight?

McLogo76   Feb 02, 2023 

I get about 3-3.5 mins with this setup with 4S 650mah tattu batteries.
And it has more than enough power in my opinion.
Also got a lighter 230gr AOS 3.5v2 with only the walksnail and 1404 3800kv motors were I easily get 4-4.5 mins flight time with the same batteries.

toni903   Feb 02, 2023 

How do you think 1504.5 and 1404 aompare? Which do youo like more

McLogo76   Feb 02, 2023 

The 1504.5 have more torque and power and I would go with them around 240 - 260gr / the 1404 for me fit the quad that is 230gr or below.
Otherwise both quads feel very similar.

716FPV   Nov 09, 2022  

i built this quad with these motors and a vista! i absolutely love it!

McLogo76   Nov 19, 2022 

Me too ;) Totally love how it handles and flies. Have fun!

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