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A 3D PRINTED DRONE THAT FLIES ON A SINGLE PROPELLER, STEERED BY AIR VANES

One propeller, four servo-driven air vanes, and no other spinning parts — thrust vectoring at model scale, printed in PLA.

by Drew Britten (abritten)

FULL CAD BOM FIRMWARE DOCS

RoboticsWorkshop

Built withArduinoTeensy3D printing

difficulty
●●●●○
time
a weekend-plus
license
GPL-3.0
repo
repo STABLE (NO COMMITS SINCE JULY 2024)39 stars

WHAT YOU’LL NEED

Videos
1
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COMPAREE VERDICT

Almost every hobby drone turns by making one pair of rotors spin faster; this one has a single propeller and steers by deflecting the airflow with four micro servos. The airframe is Benjamin Prescher's Ball-Drone Project MK II: the STL files live on Thingiverse and the twelve-component parts list and build instructions on Hackaday. Drew Britten's repository adds the piece that changes the brains: dRehmFlight firmware for a Teensy 4.0 and MPU6050, already tuned to his build. The catch is that tuning a thrust-vectoring monocopter is not like tuning a quadcopter, and your servos, vanes and weight will differ from his, so expect bench time adjusting servo throw and control surface deflection. The propeller is unshrouded, so first flights belong in a net or a large indoor space until the loops settle.

GOOD TO KNOW

  • —STL files are on Thingiverse (original Ball-Drone files plus a version modified for SG90 servos), linked from the README; the repository itself holds the firmware.
  • —Parts list: the airframe components (motor, battery, ESC, receiver, servos) are listed on the original Hackaday project; for this version you replace its Betaflight board with a Teensy 4.0 and GY-521 MPU6050 as described in the dRehmFlight README.
  • —Firmware is the upstream dRehmFlight flight controller by Nicholas Rehm, forked and tuned for the monocopter — you flash a Teensy 4.0 over USB.
  • —Assembly instructions are the original Hackaday build instructions; the README adds photos of the finished drone and the dRehmFlight circuit.
  • —Published under GPL-3.0, which permits commercial use with the same licence for derivatives.
  • —Videos: the README links the builder's string test, indoor flight and a full monocopter video, plus Nicholas Rehm's dRehmFlight tutorial series.

Parts to buy

4 items

From our check of the build. Exact quantities and part numbers are in the creator’s BOM.

  • Teensy 4.0 and GY-521 MPU6050 for the flight controllerFind
  • T-Motor F35A ESCFind
  • Four EMAX ES9051 micro servosFind
  • 6x4.2 inch (6042) propellerFind

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Can I build this?

PrintBall halves, motor mount, vane assembly and servo arms; the original designer printed in PLA but recommends PETG for strength, and most parts print without supports
BuyTeensy 4.0 (or 4.1) and GY-521 MPU6050 for the flight controller; from the original parts list: STORM TL2306 2300 kV motor, T-Motor F35A ESC, four EMAX ES9051 micro servos (or SG90s with the modified STL files), a 6x4.2 inch (6042) propeller, a 3S 1300 mAh LiPo and a receiver such as the Flysky FS-A8S
Tools3D printer, soldering iron, Arduino IDE or PlatformIO for flashing the Teensy, R/C transmitter (6+ channels), multimeter, logic analyser or oscilloscope helps for servo debugging
SkillsR/C aircraft experience and basic PID tuning — this is not a first drone, it is a control theory experiment that flies
TimeA weekend to print and assemble, then another weekend tuning the flight controller before stable hover — first-time PID tuning on a monocopter can double that
Cost$$: the Teensy 4.0, motor, ESC and battery dominate the bill; check current prices against the original Hackaday parts list
SafetyUnshrouded propeller spinning at several thousand RPM — first flights must be in a net or large indoor space. 3S lithium polymer pack requires a LiPo-safe charging bag and a balancer. Drone regulations apply: EU operator registration and open category rules, equivalent rules elsewhere.

Build at your own risk. Projects involve tools, electronics and sometimes mains voltage — follow the creator’s safety notes.

Videos

The builder's full monocopter video, linked from the README; dRehmFlight tutorial videos cover the flight controller build.

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Gallery

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Start here

Navigation into the creator’s own docs — we don’t rewrite the guide, we route you to the source.

  1. 1.Read the dRehmFlight documentation (The upstream flight controller README explains the PID architecture and channel mapping — you need to understand it before you tune the monocopter fork.)
  2. 2.Print the ball halves and vane assembly(Start with these while you wait for parts to arrive — print the servo arms last because they are the most likely to need reprinting during fitment.)
  3. 3.Flash the Teensy 4.0 with the monocopter firmware(Use the Arduino IDE with the Teensyduino add-on, as the README describes, and flash the 1.3 Beta .ino.)
  4. 4.Bench-test the servos and control surface deflection before first power-up(A misaligned vane will cartwheel the aircraft the moment it lifts off — check throw and neutral position with the transmitter before you spin the motor.)

Resources

Documentation, files and community threads for this build — we link straight to the original sources and never rehost the creator’s files.

KNOWN ISSUES

  • Mixing up the servo and STL versions: the original airframe is designed for EMAX ES9051 micro servos, and SG90s need the separate modified STL files linked from the README.
  • Skipping the dRehmFlight documentation: the README and the bundled dRehmFlight VTOL Documentation PDF explain the PID architecture, radio setup and IMU calibration, so read them before you tune.
  • First flight outdoors in wind — a monocopter has much less control authority than a quad, and a gust will flip it before the PIDs can respond. Start in a net.
  • Using a 4S battery because you have one: the original parts list specifies a 3S 1300 mAh pack, so stick to that unless you are ready to re-check the motor, ESC and PID tune for a different pack.
  • Assuming the default PID values will work on your build: the .ino is tuned to the author's drone, so your servos, vanes and weight will need adjustment. Plan a bench session before the first hover.
  • Not checking your local drone rules: depending on take-off weight and where you fly, you may need to register as an operator (EU, UK or equivalent) even for a home-built aircraft.

Can I use a different flight controller instead of the Teensy 4.0?

A Teensy 4.1 works as a drop-in alternative; the README says it is compatible with the dRehmFlight pin mappings. Moving to a different microcontroller family such as STM32 or ESP32 would mean porting the firmware, which is a separate project.

How does it compare to a quadcopter for flight time and stability?

Worse on both. A single motor at high RPM is less efficient than four at moderate speed, and the control authority from vanes in a slipstream is lower than direct rotor thrust. This is a proof of concept, not a practical platform.

What is the actual flight time on the 1300 mAh pack?

Neither the repository nor the original Hackaday project states a flight time, so measure it on your own build.

Do I need a ham radio licence to fly this?

No — the R/C link is in the ISM band, same as any consumer drone. You do need operator registration in jurisdictions with drone rules.

Community builds

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Discussion1

FROM THE COMPAREE TEAM

The whole control system is a single propeller and a set of servo-driven vanes deflecting its airflow. What would you try to tune first, the vane throw or the PID gains?

CompareeTEAM2mo agoedited

Practical notes from our verification: the repository is a clone of Benjamin Prescher's Ball Drone Project MK II, built and modified by Drew Britten using the dRehmFlight flight controller. The repo itself holds the dRehmFlight firmware versions, the dRehmFlight VTOL documentation PDF and photos of the build; the README reproduces the dRehmFlight instructions. The STL files are on Thingiverse (including a version modified for SG90 servos) and the build instructions and twelve-part component list are on the original Hackaday project. The README links the builder's own string test, indoor flight and full monocopter video, plus other builders' versions. The builder says the 1.3 Beta sketch is already tuned to his build and should only need small tweaks for yours. Even so, trim the control vanes on the bench before the first launch, because an untrimmed vane turns a hover into an instant cartwheel. Correction (4 October 2026): we re-checked this page line by line against the project's own repository, documentation and videos, and fixed errors in earlier versions.

Drew Britten (abritten)

Drew Britten (abritten) rebuilt Benjamin Prescher's Ball-Drone Project MK II, swapping its Betaflight board for the dRehmFlight flight controller by Nicholas Rehm, a general-purpose open-source VTOL stabilisation code for Teensy. His repository is the tuned dRehmFlight firmware; the airframe files and parts list come from Prescher's original project.

GitHub

Star the project on GitHub

DISCLAIMER

  • Comparee is not the author of the projects featured here. All rights to each project belong to its creator — every page links to the original source, and we never host creators’ files.
  • Information is provided without warranty and may become outdated as projects evolve. Prices are indicative bands only — always check the creator’s parts list for current costs.
  • Building and operating any project is at your own responsibility. Protective equipment, safe workshop practice and compliance with local regulations are the builder’s responsibility.
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