AOS 3.5 - Sub250 DJI Beast

By nouxtywe on Feb 03, 2022

14  892  7

17-FEB-2022: PID & FILTERS UPDATE

Hi there, it's my first time publishing a build so I hope it's on par with standards :D
Build is inspired from https://rotorbuilds.com/build/28335

This is my second AOS 3.5, the first one was with XING2 1404 motors, was 149g dry, and could use a 850 mAh R-Line. I have lost it in a forest, RIP.
This one is quite heavier, 162g dry, because of the FPVCycle 16mm motors but WOW this thing is a blast, and can fly with 750 mAh R-Line sub250 EASY.

On the picture you could remove 3g from the buzzer, 3 more grams for the TPU arm protections, and probably 2g of lipo PAD, which could bring down dry weight to 154g, which would make an AUW of 253g with 850 mAh R-Line batteries (they weight 99g).

I went with nebula pro NANO, which requires an adaptor to convert from 14x14 to 19x19.
I would rather recommend the regular nano pro for convenience (does not save more than 2g imo).

I used RENY screws for the FC and the naked vista, which saves a lot of grams compared to steel screws, and used some damping grease to maintan the nuts and reduce vibration (see link in the description).

The FC I picked is not as premium as an F7 Beast from iFlight, but does the job pretty well.
Its downside is the USB port position which does not require to remove standoff as long as you have a tiny connector and you push gently on the side of the gummy (see picture).

You can see it flying there:



I added a specific static notch filter because of frame resonance on 157 Hz that was not totally suppressed by the Dynamic Notch Filter.
I have added my BF 4.3 RC2 screens and diff, use with precaution: https://pastebin.com/KZktxCez

I have spent quite a lot of time trying to tune it, trying to follow the Basement Tuning method from Brian White (PIDToolbox) https://www.youtube.com/watch?v=sqT4MACi3d8&t=140s&ab_channel=PIDtoolbox
But after quite trial and errors, and the awesome support of their discord channel (https://discord.gg/NsgW5gZX) I finally get to find that I actually needed to DECREASE the master multiplier, which is quite counter-intuitive, if you, like me, whatch all those tuning videos :)
It apparently has something to do with the fact that those motors are a bit overpowered for the build, so these look like more "racing" PID.
You can check the step response in the last picture.
Happy flying!

Photos

Discussion

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Synadex   12 days ago  

Wow, I ordered my parts for this yesterday almost the same spec (except analogue) and the v2 frame. Cant wait!

nouxtywe   6 days ago 

you'll love it :)
I have added a new video flight I had the other day... really pleasant session!

allspi   Feb 14, 2022  

great build! ery nice rips on video. Did You consider to rotate aio by 90° to solve conflict on usb port? Have You got grease/ non grease comparison? is JHEMCU ok?.

nouxtywe   Feb 17, 2022 
1

hi, thank you :) no I did not consider it because I trimmed my standard USB cable and when I push gently on the side of the FC I can get it in every time without difficulty. JHEMCU was actually in Chris Rossers' "budget" list so I gave it a try. It's definitely on the low-cost range but the specs are ok. Can't tell on the long run for now though.

nouxtywe   Feb 19, 2022 

I did not make a test without the grease but i like the fact it replaces loctite

Flip_FPV   Feb 16, 2022  

Nice build! I have one like this with betafpv 1505 motors and it flys awesome. I got the 16mm fpvcycle motors but haven't installed them yet. I'm anxious to try them out. Thanks for posting your tuning info too, I'll give that a try.

nouxtywe   Feb 17, 2022 
1

I will update the PID because it turned out to be a bit tricky to tune with classic method :)

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