Lego Boost Competition Arrow

Inspired by DrSnor's Lego Boost Robot Spare Arrow I decided to make my own, more faithful to the original. I started afresh using TinkerCAD, the one Lego Boost arrow ("Competition Arrow") I possess, and a digital caliper.

The prototype was printed in two halves and glued together with cynoacrylate ("Superglue", "Crazy glue", "Sekundkleber") - it worked OK but the narrow rails that engage the spring in the shooter were too pronounced and not rounded like the original, and I had to trim them a bit. I reworked the model to round and narrow the rails.

Lego holes/studs are spaced at 8mm (well, very close to) and all Lego dimensions are integer multiples of 1.6mm.

The prototype is weighted with white-tac, as it tumbled in flight with the lightweight front - centre of gravity needs to be ahead of centre of pressure to get good flight. Two extra versions with built-in nose weight are included.

Lego is the trademark of Lego, no violation of Lego intellectual property rights is intended, this is an homage to the best toy ever...

Note that it's cheaper and easier to buy spare "competition arrows" from Bricklink, by the way! (Also safer as they have bigger, rubber ends. And they fly better.)

I have in mind to add a version that somehow mounts one of the standard lego tyres on the end, to make a weightier, safer rubber end.

WARNING - this has not passed any kind of toy safety testing. It can be shot from a Lego competition arrow shooter, but unless you make the front part from some kind of rubber, it's a lot harder and sharper at the business end than the proper Lego part, and might cause injury to eyes etc. Use it at your own risk. I accept no liability for any damage caused by your use of this design, and I recommend that you don't shoot it anywhere near children.