Burt's "Min5" Build Journal (w/Taranis+RaceFlight PID Tuning)


Inspired by the “disc loading” meme that I saw 1-2 months ago, I got this minimalist 5" frame and stuck on some spare parts. I really wanted to use the RaceFlight Spark 4in1 ESC that I have, but I didn’t want to cut that up – actually, it was really stubborn in desoldering the pin sockets that came pre-installed; @Denovich informs me that’s understandable due to “all that copper” in those boards. I’d thought of installing my RaceFlight Millivolt, but that would mean breaking down my Awesome E90, which has become an FPV workhorse of mine.

Well, I punted and installed a Cicada 4in1 10A ESC. Build looks tight, as you can see. I did also really want to use RaceFlight One with this Revolt V2, so I’ve been working my way through the RF1 wizards.

I tried to make this as clean as possible, with modest wiring. Since this was built from spare parts, though, I had to extend motor wires. I’m pleased with the wiring overall, which you can see in the pics.

I was stuck on not being able to bind my Orange R111XN receiver. I ended up removing it, and binding it as a satellite on a full receiver, then reconnecting. @Denovich ended up having similar experiences just a day or two ago – seems like an open item.

I had been stuck not getting the Receiver wizard to work – I needed to configure my ARM switch on the Taranis. Without that sending a signal, RF1 had nothing to configure.

I had also been stuck on the “Setup ESC” wizard, where it would fail, not recognizing the last ESC. After a thorough process of elimination, I found that I had soldered my Motor 4 signal wire to the ground pad; this process included:

  • Using the “1wire” CLI command
  • Downgrading to REVOLT_BB425_STD.bin in order to use the BF-based configurator
  • Attaching another FC (Eachine Minicube FC v1.0) to my ESC, which worked completely
  • Using the BLHeli Chrome app to flash the errant ESC (turns out it was at 16.5, while all the others were at 16.65 – weird)

Anyway, correcting that signal wire allowed me to complete all the RF1 setup just now (w00t!).

Better props and tuning are in front of me, but here are some pics thus far:

Build Gallery

I thought I was going to only need to fit the receiver – can you see how excited I might have been at just this for receiver placement?:

…but realized that I needed more reliable 5V to the FC, so I added this BEC:

Wiring for receiver, camera lead, and bridged pads for receiver signal and power:

Wired up BEC:

Wired signal harness (glad this showed me the loosened GND wire – FIXED!):

Mounted BEC and receiver on ESC:

The “mess of wires”; pretty tidy IMHO (glad to catch the lame ESC soldering – FIXED!):

Pretty tight overall, I’m pleased. Loose leads for cam and buzzer:

Ready for finishing touches:

Parts List

5" Ultra Light Frame
Raceflight Revolt V2 Flight Controller
Cicada FX10A 10A 4in1 ESC
Kensun 1806 2300KV Brushless Motors
FrSky X4RSB receiver
5V 12V Adjustable BEC

Weight w/o battery: 158.25g


@burtlo: No doubt that lowering AUW and disc load makes a huge difference! Hope this flies as well as it looks good! :smiley:

On a related note, you might want to read through the ultralight tubular quads thread over on RCG. Lots of incredibly lightweight builds there, including a recent one with 2204 motors that’s almost as light as your typical 1407 build.

Sweet! I had bought a couple tubes months ago, but hadn’t figured various motor mounts. I’ll enjoy that thread, thanks!

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Woof! Wild oscillations right out the gate, regardless of the presets used in RF1 Configurator. I’ve got some work ahead of me.

I’m going to hack at the Taranis PID Tuning once and for all, so I don’t have to wear out the USB port.

Obviously once you have it flying nice, could you post a few videos? One with a LOS punch out would be most welcome :slight_smile:

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Thanks for sharing your build with us again! i love all the eye candy and pictures :slight_smile: sorry to hear about the bind mess. I HATE binding, i def have some sort of ptsd related to binding because every time right before i try to bind something i get all nervous its not going to work lol

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We can heal that PTSD, @quadlifepro, just keep coming back. :slight_smile:

I’m worried that the arms are too narrow; thick enough to be stiff, but not wide enough to not twist. We’ll see if I can get this tuned properly… this will be my first real tuning challenge, with as wildly off the mark it is.

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Good luck sir! Bring the laptop outside and set up a tuning station outside and a nice cold lemonade lol

is the build LOS for now? if so that may not be so difficult to get a base tune going…

It is LOS, but I want to figure out the Taranis PID tuning hack.

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I love how you are always up for the challenge. Inspiring!

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Following this recipe: https://oscarliang.com/pid-vtx-settings-taranis-lua-raceflight/

I needed to flash my Taranis with firmware that was properly configured for running scripts. This is

I needed to create the matching folder structure to place the LUA scripts within

Wiring up a spare XSR (though I was told it MIGHT be broken) – hoping to install temporarily (dev) alongside the R111XN (prod) to use RX3 (dev) instead of RX1 (prod). XSR Manual here: http://img.banggood.com/file/products/20160119004828XSR(2).pdf

OpenTX Companion is (happily!) multi-platform – OSX native app is found within download for each firmware version – lots of software pieces though

OpenTX University! Whoa – http://open-txu.org/home/grad-school/lua/foundations-of-lua/

How to add a LUA script: https://www.youtube.com/watch?v=emzo0jN-x9A

Setting up PID Tuning on RF: https://raceflight.net/taranis/ --> https://www.youtube.com/watch?v=GySo4TnDqWQ

XSR ended up with magic smoke, so using an X4RSB that I had in the vault.

So, with everything installed thus far, using an X4RSB via TX1 SBUS and connecting the SmartPort to RX3 on the Revolt V2, all I get when I activate the LUA script is “No RX Detected”.

I get voice prompts that detect when Telemetry is LOST or CONNECTED, so I think that means there’s signal to RX3, doesn’t it?

I’m asking for help on RF’s Slack, but wondering if anyone else has any ideas?

So, it seems I have PID tuning implemented in the Taranix Q X7 with my RaceFlight Revolt V2. I did a test, modifying my Pitch P term on the Taranis, and then double-checking in the RF1 configurator… the value was changed!

I don’t have a TBS Unify, and this is LOS anyway, so not cam parms to modify. I’m getting the constant message of “No RX Detected” whenever I activate the LUA script. When I look at the script itself, I see that it’s notifying me of no RSSI value:

@las helped me to learn more about RSSI and Taranis sensors (page 12 on the Q X7). Discovering sensors on my quad made the message go away.

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@denovich helped me realize that i had tested my motors using 0-based (zero) values instead of 1-based values. So, I typed “idle 1” to test for motor position 1 (front-left), but I should have typed “idle 0”. As such, all my motors were positioned 90° to the right of where they should have been.

Hover test was good!


Here you go, @yets:


That zips pretty good! I approve.


This was with the GemFan 5020s, quiet, but hardly any bite. I’m awaiting other props to play with, but I might try the RotorX 3040s.


How does it feel to fly burtlo?

It feels light and nimble, pretty darn cool! I’m a little gunshy because it’s larger, but I have a bunch of builds of varying sizes, and they usually feel “solid”. This feels “lean”, like I could get hangtime more easily than most other quads.

I’ve loaded it up with a “360° Camera Mount” that I got from Dan Thompson in England: about 110g with Mobius Mini and counterweights, total w/o battery is now at 272g. It won’t feel so lean now. :slight_smile:

This is just playing around, though, I won’t keep the cam mount attached. I plan on some LOS acro with this after I try the cam mount.

If you were looking for a fun build, I would recommend it. It’s different than purpose-built kits, like racers, and I think it’s pretty elegant actually. Still looking forward to playing with props, and remember, this is with “leftover” motors, so picking some different motors would also provide more to play with.