Is this for you?
Who it's for
Engineering students, hobbyists and working CAD designers. Enter solo or as a team. You need to be 18 or older.
What you'll make
One complete drone, one subsystem a month, in a public repo that shows every revision. It's a portfolio piece you can link to.
What you need
Any CAD tool that exports STEP and a free Nurbly account. No hardware, no budget, no Git knowledge.
What you get
- Written feedback from the judges after every stage.
- A chance at a cash prize every month, not just at the end.
- A public design history to show employers and clients.
- Other teams fork and remix your design in the final stage.
- Your design stays yours. You keep the IP.
Keeping the IP means you own your design, but your entry is open source. You choose an open license, such as CERN-OHL or CC BY-SA, and anyone can view, fork, build and reuse your design under its terms. Nurbly and its sponsors may also show your work to promote the challenge. Section 6 of the rules has the details.
How to enter
Step 1
Step 2
Make a free Nurbly account and a public repo with nbc-2027 in its name or description. Add an open source license.
Step 3
Each month, upload your STEP files and notes on your decisions.
Step 4
Before the deadline, tag the version you're submitting stage-N.
A few words you'll see: a commit is a saved version of your files. A tag marks the version you're submitting. A fork is your own copy of another team's repo, and a pull request offers your changes back to them.
Prizes
Grand prize
$1,500
Highest total across all six stages, bonuses included.
Stage prizes
$250
Highest score in each of the six stages.
Best design history
Sponsor prize
Best documentation
Sponsor prize
Best physical build
Sponsor prize
Community reach
Sponsor prize
$3,000 in cash prizes. The judges decide the four sponsor prizes. Community reach goes to the entry with the highest community interest score, from stars and forks, across the stages. Sponsor prizes are announced here as sponsors confirm.
Key dates
Registration
Open now
Closes 25 Jul 2027
Stage 1 opens
1 Mar 2027
Stage deadlines
Last Sunday of each month
23:59 UTC
Final deadline
29 Aug 2027
23:59 UTC
Joining late? You can still win the stage prize for any stage you submit. To be in the running for the grand prize, submit Stages 4, 5 and 6.
Stages
One stage per month. Each one builds on the last.
| Stage | Month | Deliverable |
|---|---|---|
| stage-1 Thesis and airframe | Mar | A thesis stating what the drone is for and the requirements that follow. Arms, body, landing gear and motor mounts as STEP. Printable or machinable. |
| stage-2 Electronics layout | Apr | Flight controller, ESC and battery mounts, cable routing. PCB outline if custom. |
| stage-3 Propulsion | May | Motor selection and prop guards. Thrust math documented in the repo. |
| stage-4 Control and sensing | Jun | FC mount, camera or sensor gimbal, antenna placement. |
| stage-5 Integration | Jul | Full assembly, interference check, mass budget, BOM. |
| stage-6 Release and remix | Aug | A v1.0 release with build guide, BOM and drawings. Remix another team's entry for up to 50 of the stage's 100 points: fork it, change one subsystem, and open a pull request. You can submit your release without a remix. |
How it is judged
- Engineering quality35
- Design process20
- Integration with prior stages20
- Documentation15
- Community interest10
Stages 1 to 5 are scored out of 100 as above. Stage 6 scores your release (50) and your remix of another team's entry (50). The remix is optional, but skipping it gives up those 50 points. Every stage also offers up to 10 bonus points for merged pull requests from outside contributors, and up to 5 for a physical part.
There is no minimum commit count. Judges read your whole history, and recorded decisions and revisions that improve the design score higher than one finished upload on deadline day.
Rules summary
- One public, open source Nurbly repo per team, with
nbc-2027in its name or description. - All models as STEP, from any CAD tool.
- Tag each stage
stage-Nbefore the deadline. - Start with a thesis: what your drone is for.
- Civilian, lawful designs only.
- Late joiners welcome from any stage.
- Participants keep their IP and choose an open license.
- You must be 18 or older.
FAQ
Do I need to build the drone physically?
No. A physical build is optional. Each stage offers a bonus of up to 5 points for a photo of a physical part of that stage's subsystem, at any scale.
What CAD tool do I need?
Any tool that exports STEP. Nurbly shows STEP files in 3D right in the browser and compares revisions face by face, so judges can see how your design changed. Native files, like SolidWorks parts, can live in the repo too. Only STEP gets the 3D view.
Do I need to know Git?
No. Nurbly runs on Git, but you never type a git command. Upload files in the browser,
or use the free nrb command line tool and desktop companion, which offers to
check in changes from your system tray.
What does Nurbly cost?
Nothing. Challenge repos are public, and public repos on Nurbly are free with no limit on collaborators. A team of any size can compete on free accounts.
How big can our repo be?
A free Nurbly repo holds up to 500 MiB. That is plenty for STEP files. Keep build photos and videos compressed.
Can I join late?
Yes. You can join from any stage until registration closes on 25 Jul 2027. A late team can win the stage prize for any stage it submits, and the grand prize if it submits stages 4, 5 and 6.
Where do I ask questions?
Email us at . You can also ask on our Discord.