Maker Paul Songer has created his own 3D printable Batarangs based off of the foldable design seen in the Arkham series of Batman games.
The two “blades” join the central hub with some glue and don’t require any other parts such as bearings or hinges. If you make your own just remember to sand them down so you don’t get the horrible scraping sound of rough plastic.
Unfolded the Batarang measures in at around 12″ (30.48cm) wide. Songer states that this is purely a cosmetic item, and we don’t think something that big would fly anyway.
You can find the files to print your own over on MyMiniFactory. Alternatively, finished models can be bought from Songer’s Etsy store for $15.88 (~R207).