Benchycopter

My role

Co-author with Sebastián Varela · EUCD/FADU/UdelaR · 2021

Pair-based parametric design: joint work on propeller geometry, snap-fit shaft system and the final technical sheet.

Executive summary

A digital fabrication project. The brief asked us to design an object that took advantage of the specific affordances of FDM 3D printing, exploring print-in-place logic (parts that come off the bed already assembled or self-snap-fitting).

We combined two icons of maker culture:

The Benchy — the reference boat used to benchmark 3D printers, recognized across the maker community. The "Benchy language" implies recognizable, easy-to-print shapes.
The string-launched helicopter — a classic toy launched by pulling on a cord/zip tie that spins the propeller and gives it vertical thrust.

That crossover gave us the Benchycopter: a helicopter with a 3-blade propeller and a Benchy-style chassis + snap-fit shaft + a 226 mm zip-tie launcher.

Project details

The product

Full Benchycopter render — body, 3-blade propeller, shaft and zip-tie launcher.

Render of the Benchycopter in flight.

Concept

A helicopter designed to be fabricated entirely in a single 3D-printing run. The bottom of the chassis acts as the launcher — pulling it spins the propeller and releases it, sending the rotor flying. The visual language is simple and friendly for any age, drawing on the Benchy aesthetic.

Components

Part	Function	Dimensions
Propeller (3 blades)	Generate thrust by spinning	Ø 122.2 mm · 6.5 mm thick
Snap-fit shaft	Propeller ↔ chassis assembly	37.3 mm tall · 4–5 mm diameter
Benchy-style chassis	Helicopter body	inside the Ø 226 mm rotor
Zip-tie launcher	Pull to spin the propeller and launch	226.4 mm long

Technical appendix

Technical sheets

General views

General views of the assembly (original document, in Spanish) — top, side, front, isometric. Rotor diameter 226.4 mm.

Propeller

Propeller views (original document, in Spanish) — Ø 122.2 mm, 3 blades with simple aerodynamic profile, 6.5 mm thick.

Shaft

Shaft views (original document, in Spanish) — snap-fit system (4 mm at top · 5 mm at bottom) with 37.3 mm total height. Benchy-style snap-fits for tool-free assembly.

Development and validation

Fabrication notes

Annex (original document, in Spanish) — first-version joint detail. The first iteration of this joint had stability issues due to the size of the part acting as the rotor axis.

Iterations:

First version of the shaft: stability issues caused by the magnitude of the part acting as the rotor axis. Redesigned with larger diameter and better mass distribution.
Snap-fit between shaft and propeller tuned so the propeller could release from the shaft when reaching takeoff velocity (it flies freely once the launcher stops applying force).

Results and learnings

What I learned

Using 3D-printing logic as a project constraint — designing the object from the start as something that comes off the bed already assembled, not as something printed-and-then-bolted-together.
Mixing cultural references — the Benchy is shared language in the maker community, and combining it with a classic toy produced an object that's understood without explanation.
Iterating the mechanics — the first shaft didn't work. It had to be redesigned to provide rotational stability and allow release at takeoff speed.
Pair work with Sebastián Varela — short project but with the same divergence/convergence dynamic we applied in longer projects.

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