The aim: very, very easy
Rotorflight is an excellent flight controller, but setting it up is hard. We want to make it very, very easy. Easy enough that an experienced flyer can set up and tune a Rotorflight helicopter without learning Rotorflight's vocabulary, and without a laptop or the Rotorflight Configurator, its computer program.
The new LockDownRadioControl receiver (RXV2) connects to a Nexus X, or any other Rotorflight flight controller, with one cable. That one lead carries your stick commands to the flight controller (Rotorflight calls this link CRSF) and telemetry back: volts, current, head speed, ESC temperature and the flight controller's own status. Nothing else to wire up.
The free phone app connects to the receiver by Bluetooth and sets up Rotorflight in the field, in the kitchen, or wherever the helicopter happens to be. The pages speak plain English, and the firmware term is there in brackets for anyone who wants it.
You do not need our radio. Fly Rotorflight with Futaba, Spektrum, FrSky, ELRS, Crossfire — anything — and the dongle gives you the same app on the helicopter you already have. It is a tiny board that lives in the model: keep your transmitter, keep your receiver, change nothing about the way you fly. The one-page guide shows what to do.
Make your own dongle in about ten minutes. One small board — a Seeed XIAO ESP32-S3 — and the four-way lead that came with your Nexus. How it goes together, and one click puts the software in.
For the USB way you also want a short USB-C lead that carries data: a Chenyang CY-UC-088-0.07M, 70 mm, flat, right-angled — one like this. A charge-only lead is the commonest reason a board seems dead.
Get the app — and be a tester
It is free, and on the App Store and Android now. I would very much like people to try it and tell me what is wrong with it: anything that stops you mid-job, wording that confused you, anything you expected to find and could not.
No hardware yet? Try it anyway. Tap Demos on the front screen and the whole app runs against a simulated helicopter — nothing to plug in, nothing to break.
If something goes wrong, open the Event log page and tap Send debug data to Malcolm. It gathers what the receiver and the app actually did — no passwords, no WiFi details — and hands it to your share sheet. That one tap tells me more than an hour of questions.
What makes it easier
Blades off, or motor unplugged, before touching anything in the app. Setting up is done on the bench, never with the rotor turning. The app refuses to change anything while the model is armed.
Two wires, everything. The receiver lead carries the flying and the everyday pages. A radio’s own Lua scripts have only that tunnel, slow and limited to 320-byte replies, so they stop there. A short USB-C cable from the receiver to the flight controller adds the configurator’s own channel: every setting, any size, the command line, ports, a factory reset, and the black box. With both wires the app can do everything the configurator can, apart from flashing Rotorflight itself.
- One lead for flying. Receiver to flight controller is a single lead: control in, full telemetry out, and the phone talks to the flight controller through it. No extra wires, no telemetry adapters.
- A short USB-C cable when you want the whole configuration channel. From the receiver's USB socket to the flight controller's. The receiver adopts it by itself, nothing to set, even with the transmitter on. The lead keeps flying the model; the cable only carries the setup conversation, and it can stay in. Buy the shortest one you can, right-angled at both ends. The one in the photo is a Chenyang CY-UC-088-0.07M: 70 mm, flat, USB-C at both ends, both plugs right-angled, USB 2.0 data and 65 W. Search that part number. Anything similar will do — what matters is that it is short, angled at both ends, and carries data, because many short USB-C leads only charge. Tie it down and leave it in: it costs nothing in the air, because the receiver stops talking over USB the moment the radio link is live. That unlocks In-flight adjustments, the Command line and a factory reset of the flight controller, and lets a brand-new receiver set its own port on the Ports page.
- Ports, without the configurator. One plain choice per flight-controller socket: receiver, dongle on a wire, ESC telemetry, GPS, blackbox logger and the rest, named as printed on a Nexus-X. A new receiver never needs the computer: USB cable in, Ports page, choose “receiver” for its port, done.
- Filters in plain English. Lowpass, rotor-speed notches, dynamic notches and fixed notches; changes take effect at once. The help explains how to read the vibration chart: peaks that follow head speed are the rotor, a peak that stays put is something else vibrating, noise everywhere means lowpass 1 should come down, never below 60 Hz. A "Filter check" is in the works: the receiver reads the black box, works out the vibration against head speed and recommends which filter to change.
- In-flight adjustments. A knob or a switch on the transmitter changes one setting while you fly, for one flight mode (Rotorflight calls these banks): "Yaw P gain in bank 1". Choose the setting and the boxes fill with its current value, ready to edit (with the transmitter on, only for the bank in use), with a live bar showing where the switch is. Set up with the USB cable; afterwards the adjustments live in the flight controller and work with the cable out.
- The command line. Rotorflight's own command line from the phone, every setting by name: get gov, set gov_gain = 40, diff, dump. Needs the USB cable, and is refused while the transmitter is on.
- Any receiver, with the dongle. A tiny board, by USB or on a spare flight-controller port, gives the whole app on any Rotorflight helicopter, whatever radio flies it. Keep your radio, try the app. Dongle quick start.
- Sliders that never run out of travel. Every slider's centre means the numbers you had at your last backup. Back up, and the sliders re-centre while the numbers stay put.
- Find a setting. Type a word or two, in your words or Rotorflight's, and every matching setting is listed with the page it lives on. Tap it and the page opens with that setting lit up.
- Plain-English screens. "How hard should it start?" rather than gov_startup_time. Every underlined term explains itself when you press and hold it.
- Sliders where the numbers used to be. How hard it starts, how agile it is, how the sticks feel, softer or sharper. One slider moves the right set of numbers together, and the numbers stay visible underneath for those who like to see them.
- Every change is checked. The page tells you what was changed and confirms the flight controller now holds exactly that.
- Banks that behave. Tune one bank, then copy it to the others with the gains adjusted for each bank's head speed. After a phone session the flight controller goes back to whatever bank your transmitter's switch has selected.
- The whole setup backed up to the phone, restorable to the same model or a new one, and taken with you to a new phone.
- The full toolbox from the phone: gains (PIDs), stick response (rates), governor, rescue, servos, travel extents with the pitch gauge, switches and modes, the flight recorder, and ESC settings for Scorpion ESCs.
- Telemetry on the transmitter: volts, head speed, ESC temperature and more, straight from the flight controller. A guard stops the Rotorflight 4.6 fault that can silently switch telemetry off after a save.
- An express wizard, in the works. Pick your helicopter, motor and ESC from lists. Sizes, gear ratio and telemetry come with them. Then a few hands-on steps, each confirmed by the flight controller's own reading. The target is a new helicopter flying in ten minutes.
A Goblin 770. A very short USB-C cable, right-angled at both ends, tied down and left in permanently.
What it looks like
Screens from the iPhone app. The Android app shows the same pages.
The Rotorflight menu
Find a setting: type a word, tap the result
On a dongle: any receiver flies the model
Easy tuning: the sliders in one place
PIDs, with softer and sharper
Governor: how hard should it start?
Copy a bank, adjusted for head speed
Backup and restore on the phone
Switches: what each one does
Ports: one plain choice per socket
Filters, in plain English
In-flight adjustments: a knob or switch changes a setting
The command line, from the phone
Pick a receiver by name, and photograph
Flight simulators
The same receiver flies your simulator. Plug it into the computer by USB, switch it to simulator mode from the phone, and it appears as a joystick and a keyboard. You fly RealFlight or neXt with your own transmitter, exactly as you fly the helicopter, on Windows or Mac.
- Simulator buttons from the phone or the transmitter. RealFlight's menu (select, up, down, cancel, reset) and its camera views; neXt's keys (new model, engine, pause, self-level, trainer, piro trainer and the rest). Every key is editable on the phone, and transmitter switches can press them too.
- Realistic spool-up in neXt. Most simulators snap a helicopter's motor straight to full speed. The receiver ramps it like a governor, so the model spools up like the real thing and an autorotation bail-out recovers head speed at an honest rate.
- Channels remapped in seconds. Any receiver channel to any simulator output, reversed if you like, with live bars showing what the simulator sees.
- For any transmitter: the dongle is a simulator interface too. Set the same little board to Simulator interface and it turns almost any receiver into that same USB joystick — CRSF, SBUS, IBUS or PPM, recognised by itself — so a friend with a different radio can fly the simulator as well. One board, both jobs: how it wires up.
RealFlight: menu and camera views
neXt: every key on the phone
Channels to simulator outputs
Any receiver: the dongle — and your simulator
Not everyone wants a new radio. Keep yours: the dongle gives the whole app on any Rotorflight helicopter, whatever receiver flies it. It is the receiver's little brother: the same brain, no radio.
Two ways to connect. By USB: a USB-C cable from the flight controller's USB socket to the dongle, plus its lead into a Nexus-X port B or C for power (5 V from the flight controller, never from anything else). Nothing to set. Or, once set up, by the lead alone: with the USB cable still in, set that port to “dongle on a wire” on the Ports page, or once in the Rotorflight Configurator (with the dongle's USB cable out), and the lead is then the whole connection. It lives happily in the model, goes quiet when the model is armed, and comes back when you disarm. Loan dongles: ask me for one. New to all this? Start with the one-page guide. Wiring details are on the dongle page.
The same board is also a simulator interface. Choose that role in the app and the dongle turns one of your receivers into a USB joystick for RealFlight or neXt, on Windows or Mac: the receiver’s signal, 5 V and ground on the same four-wire lead, and the computer powers the pair of them — no battery, no flight controller. It recognises CRSF, SBUS, IBUS and PPM on its own. How it wires up.
Windows and Mac too
The same setup pages already open in any web browser over the receiver's WiFi. Windows and Mac apps will follow for those who like a big screen at the bench. Phone, tablet, computer: one set of pages, one way of working.
Updates over the air
The receiver updates itself
New receiver firmware is published on this website. The app announces it, and one tap installs it over the air, web pages and all, while your settings and backups are kept.
The new transmitter will too
The V2 transmitter is being built now. When it is done it will update the same way, straight from the phone, with no cables and no computer.
Where to get it
The Android app is on the Phone Apps page and keeps itself up to date. The iPhone app will follow. LockDownRadioControl is free and open source: the V2 receiver, transmitter and app are added to the LockDownRadioControl V2 repository as they are released, and the original V1 transmitter and receiver are in the LockDownRadioControl repository. Both are free to use and to change, under the GNU General Public Licence.
If you fly Rotorflight and would like to try it, get in touch. Receivers are inexpensive to build and I am happy to help.