Rubber Band Powered Helicopter

This Rubber Band Powered Helicopter is a simple, fully 3D-printed flying
model with no tail boom, no gears, no electronics, and no extra hardware.
Just two contra-rotating rotors and a rubber band between them—that is the
whole idea.

Wind the rotors, store energy in the band, and let go. The top and bottom
rotors spin in opposite directions, canceling torque so the body stays
stable without a tail rotor. Lift comes from the combined action of both
rotors working together.

The design is intentionally minimal. Print the parts, add one rubber band,
and you are ready to fly. No screws, bearings, motors, or purchased kit
parts are required.

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A rubber band runs directly between the upper and lower rotors.
There are no gears—the band connects the two rotors and does all the work.
When you wind the model, the band twists and stores elastic energy. On
release, the band unwinds and drives both rotors at the same time—but in
opposite directions.

Because the rotors turn against each other, their reaction torques cancel
out. That is why this helicopter does not need a tail boom or tail rotor.
The contra-rotating setup does the job in a clean, compact way.

Everything you need is printed in plastic except the rubber band. The
fuselage holds the two rotors in alignment and gives you something
to grip while winding.

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- A 3D printer and filament
- One rubber band
- One drop of glue

That is it. No other parts to buy or hunt for.

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I printed mine on a Bambu Lab A1 mini using PLA. Keep prints light where
you can; less weight means better lift from the same rubber band.
Use a drop of glue to secure the hook to the upper rotor from the top.