Designing Lego Battle Spinners: Part 2 (Using Physics!)

In my first post, I introduced Brick Spinners as a fun and competitive way to use those piles of building brick toys to entertain and foster the sporting whimsy in your kids. In the follow-up, I began discussing aspects of Brick Spinner design, including aesthetics, weapon height, and reinforcement.

I continue the discussion of optimizing Brick Spinner design in this post, in which I use the principles of physics (which I won’t bother to explain) to instruct how to gain maximum performance from your Spinner.


To spin without wobbling or slowing down, a Brick Spinner must be symmetric across two axes or mirrored rotationally. 

As an example of a two-axis symmetric design, if you could fold The Hammer in half along the yellow axis (image below), the two halves’ silhouettes would match. Likewise, if you folded him in half along the red axis, the left side mirrors the right side.

My 10-year-old’s Small Class spinner Sideswipe is an example of a spinner that is symmetric across neither axis, but is still balanced because its opposing sides are rotationally mirrored. Incidentally, Sideswipe is currently the Small Class champion due to its robust and centrally-compact design. More on that later.

Even the Ridonkulus-class champion Flak-o-Lash, designed and built entirely by 5-year-old George (with no help from Dad or Big Brother, no kidding!), follows this key design principle:

Rotational Velocity vs Striking Power

Other design choices may be performance-driven, based on its creator’s inclination.

For example, a Spinner with most of its weight centrally located about its axis is going to be easy to spin at a higher speed, and also will tend to be harder to knock off the table because of its heavy centralization of mass.  Medium-class rookie spinner Fire Truck is a great example of a fast-spinning beefcake with dainty Hitty-Thingies. It may look ungainly from the photo, but Fire Truck is one of the easiest Brick Spinners to get going at an extremely high RPM.

On the opposite end of a spectrum, a more weight-distributed or centrally-lighter spinner may have war hammers installed at the ends of its Hitty-Thingies.  In the photobelow, The Hammer (appropriately) has been modified to add clubs at the ends of its wings.  This addition makes it more difficult to spin The Hammer at a high RPM, however, it really packs a wallop due to the extra mass at the ends of its wings.

Other weapons to try include protruding spears to hook the opponent and send it flying SR-71 is a good example), or even sloped pieces to get underneath and upend an opponent. See how you can use those oddly-shaped unique brick pieces to your advantage!

SR-71’s ‘Hooky-Thingies’

Balancing Weight

One thing you will notice as you build your first spinners is that you need some counter-balance to prevent wobbling.

Fire Truck was first built without the stubby little cross wings that protrude from underneath its wheels. On its first few spins, even though its weight is concentrated in the middle, Fire Truck had a severe wobble problem.  The long Hitty-Thingies could very easily tilt just due to an imperfect spin, and the tips made contact with the table.  When one tip hit the table, it would bounce off of it, causing the other side to dip and hit the table. The subsequent wobble and continued tip-hitting created a drag that slowed Fire Truck’s rotation rapidly.

To compensate, I rebuilt the under-core of Fire Truck to add the stubby wings. Although those wings will never have the reach to strike an opponent, they provided just enough stability to allow Fire Truck to become one of the easiest-to-spin and fastest-spinning thoroughbreds in the stable.

Some Spinners, of any size, may be designed so that they have four Hitty-Thingies of equal length. An example of this design style may be seen in Small Bite, the champion of the Adorable weight class.

Small Bite
‘Small Bite’

There are an infinity of ways to design a Brick Spinner. You should encourage your kids to design their own, to experiment, and to get creative. And then, when your dadly designs decimate theirs, you can patiently explain the principles covered in these articles and help them reinforce and balance their Spinners.

When that is accomplished…hold a family tournament! Spin…with style!

More Lego Spinners:

Chris Perry

Chris Perry is a contributing writer for, a website for dads by dads. Inspired by his two boys Mark and George and his wife Emily, Chris loves to make things, learn things, and loves doing fun stuff with his family.

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