Introduction

∨ I’m sure that many here will agree that LEGO® has no higher purpose than in the construction of swooshable flying machines. This little jet plane is one of my favorites…

∨ And thanks to a very cool design by favorite builder Seaman SPb, I now have a brand new spinning space Ferrari to swoosh around. I call it a “spinship” for short.

This particular spinship is modeled after the 2156 Ferrari 908W coupe — a high-performance luxury sports ship in the grand touring tradition. The “W” is for warp.

∨ Starboard instrument pod with US Coast Guard-compliant running lights…

∨ Inside the cockpit…

∨ Yesterday, I took the Ferrari out for a little spin through the inner Zargon system at warp 12 — except through the curves, of course.

∧ Glad I caught this chicane! The inner planets line up like this only once every 27.3 Earth years.

Whee doggies! This thing can move!

∨ Built-in swooshing handle…
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Swooshing sounds being mandatory, AFOLs generally have to do their swooshing when no one else is around — especially when a bath towel cape is also involved.

∨ But wait, there’s more! A 27 cm “swooshie stick” for those hard-to-reach maneuvers…

∨ Just remove the red tip holder, leaving the black 4x4 round brick in place…

∨ Then attach the swooshie stick adapter to the 4x4 round brick and overlying plate.

∨ The 12 studs and 3 Technic ball joints recruited by the adapter make for a sturdy swooshie stick attachment with a single-DOF hinge joint that stays put…

Spinship top

Back on the ground, the space Ferrari doubles as — what else? — a working spinning top! And a pretty good one at that.

Turntable-based planetary top starter

The spinship has low ground clearance and a lot of inertia by design. Unpracticed hands tend to have trouble with that combination, but it doesn’t have to spoil the spinship’s play value as a top.

∨ This matching third-generation 4:1 planetary starter lets everyone get in on the fun.

∧ Having had lots of top-twirling practice, I get launch speeds of ~500 RPM and spin times of ~55 sec by hand and ~900 RPM and ~105 sec with the starter.

∨ The starter is a lot more compact than any of my first-generation and second-generation planetary starters based on the bulky “hard plastic wheel with small cleats and flanges” (64712).


∨ Every planetary gear train needs a ring gear or annulus with inward-pointing teeth. This starter takes advantage of the 24-tooth ring gear inside a large Technic turntable.

∧ The sun and 2 planet gears are all reinforced 8-tooth spurs. The resulting backlash would be an issue in many applications, but not in a top starter.

∧ I still like my second-generation starters for their greater torque capacity and smoother operation. But this new one works well enough with the spinship, and you can’t beat the color match!

Design notes

∨ The first time I laid eyes on the Flying Cat by favorite builder Seaman SPb, I knew 2 things: (i) I’d soon be swooshing my own civilian version. (ii) It would double as a working top.


∨ The centerpiece of Seaman’s design is of course the long and graceful 9x3x5/3 bubble canopy (47844) with dedicated 10x4x2 windscreen (47843).

Finding that I had both the windscreen and a canopy with the red circle and vernier pattern (47844pb01) on hand made my week.

Once I get the necessary 4x4 wedges (43708), I’ll do a 2nd spinship with an uppermost tier more like the Flying Cat’s — but still without weapons. (Make love, not war!)

∨ Making working tops out of circular “rings” of 6x6 and 10x10 round corner slopes was already familiar territory…


∨ I’ve even been known to stack the smaller rings on the larger…

∨ And some of the tops have been kinda spacey…

But I was so top-focused that I never thought to break a ring’s inherent 4-fold rotational symmetry with a midline structure as asymmetric as Seaman’s canopy and tail section.

The spin axis would have to go right though the canopy to make a top out of this, and that posed 3 major challenges…

∨ Tip assemblyA wobble-free top needs a wiggle-free tip smack on the intended spin axis. And tip rigidity is doubly important in a top as heavy as the spinship. A stiff, well-aligned, low-friction tip assembly was therefore the first order of business.

∨ Problem was, the canopy blocked any through-going central axle that might have provided secure mounts for the stem and tip. That meant a tip assembly plastered studs-up onto the bottom of the raft of plates holding the ring of 10x10 round corner slopes together from below.

∧ Keeping the tip from wiggling in such a heavy top in the absence of any other support took some doing, but this solution works well enough.

∨ Stem assembly:

Lack of a through-going central axle also complicated stem design. The spinship needed a stiff stem assembly well aligned with the tip without detracting too much from the flowing lines.

∧ Spaceships generally don’t need rollbars, but I’m content with this solution.

∨ Balance:I was determined to give the spinship a distinct nose and tail, as Seaman did with his Flying Cat. And I was dead-set on this profile…

Getting the dynamic balance needed for smooth spins despite the fore-aft asymmetry was the 3rd major challenge — and boy, was it a doozy! I’ll spare you the details and the cussing.

Optional: Crater tops — a favorite genre

LEGO® tops based on circular rings of 6x6 (95188) and 10x10 (58846) round corner slopes have long been favorites of mine. Performance is first-rate, and the platform supports many interesting visual design options.

∨ For lack of a better term, I call tops made of rings like these “crater tops” for the bare ring’s resemblance to the wall of a Martian or lunar crater.

∧ Ring of dark green 6x6 round corner slopes on a 12x12 base.

If you have any interest in LEGO® top-making, I suggest you give crater tops a try.

∨ Crater tops with 12x12 rings:

 A ring of 6x6 round corner slopes is of course 12x12 studs in outside dimensions. The largest square plate the central opening can accommodate is 4x4. Most of my crater tops with 12x12 rings are plate tops.

∨ The 10x10 octagonal plate (89523) provides a sturdy mount for a 12x12 ring.

∨ Better yet, the plate’s central axle hole allows you to join the stem and tip assemblies with a through-going axle. This arrangement generally makes for better aligned and more rigid stems and tips, and that reduces wobble.

∨ A 12x12 crater top makes a great platform for color mixing effects.

∨ And for clutch tops with stems meant to lift off at launch…

∨ The stems on these crater tops are intentionally too short to twirl by hand. The chuck on the wind-up starter at far left works with both of these tops. The top on the left also accepts the DBG dog and centrifugal clutch adapters near the center.

∨ Since the parts are usually pretty cheap and widely available, the designs possible with a 12x12 crater top are limited only by your imagination…
∨ Crater tops with 20x20 rings:A ring of 10x10 round corner slopes is 20x20 studs in outside dimensions, but the largest square plate fitting inside the central opening is only 6x6.

∧ I like the color schemes these large rings support.

∨ Ring of dark tan 10x10 round corner slopes on a 20x20 base…

∨ TLG doesn’t make a plate large enough to mount a 20x20 ring securely all by itself — at least not one with a central axle hole. But you can still make a 20x20 ring into a plate top with a multi-plate foundation. This example retains a central axle hole.

∨ The spinship is unusual in that the superstructure built on the 20x20 ring didn’t allow a through-going central axle. Hence, no need for an axle hole in its plate foundation…

∨ Mounting a 20x20 ring on a studless hub and spoke “suspension system” opens up many fun possibilities, but the whole thing will have to be pretty stiff to avoid wobble.

∧ Suspension system attachment points include the axle holes in the 10x10 round corner plates and various tubes on their undersides.

∨ This sturdy suspension system mounts two 20x20 rings base-to-base…

∨ My first 20x20 crater top spaceship, the Blacktron Chamberlain-class Capitulator (right) from late 2015. Note the 4-fold rotational symmetrythroughout the structure. Unlike the spinship, this one basically balanced itself.

Mechanical benefits: A typical crater top has many winning mechanical attributes:

  • The “down and out” mass distribution of the ring itself tends to give the top as a whole a lower than average center of mass (CM), a higher than average axial moment of inertia (AMI), a very high AMI per unit mass, and a higher than average AMI/TMI ratio, where TMI is the transverse moment of inertia about the tip. This combination of mass properties allows the top to resist aerodynamic and tip-related braking torques while remaining upright down to very low speeds.
  • The ring’s inherent 4-fold rotational symmetry invites the same symmetry in ring attachments, and that guarantees static balancewhen all parts are fully seated.
  • The rigidity of a well-engineered plate-based crater top effectively eliminates elastic wobble at speed. Crater tops with studless suspension systems are generally less rigid but can still be wobble-free.

Together, these attributes give crater tops exceptionally long, smooth spins.

∨ This low-slung, high-AMI 20x20 crater top is stable down to speeds below 100 RPM. For a LEGO® top, that’s pretty slow.

Specifications (spinship only)

Overall dimensions: 160x124 mm (DxH) with stem assembly, 160x56 without
Mass: 184 g with stem assembly, 176 g without
Launch speed by hand: ~500 RPM
Spin time by hand: ~50 sec
Launch speed with starter: ~900 RPM
Spin time with starter: ~105 sec
Topple speed: ~200 RPM
Modified LEGO® parts: Tip cut from 4L antenna
Non-LEGO® parts: None
Credits: Original MOC inspired by the Flying Cat MOC by favorite builder Seaman SPb
See also: Swooshable jet planeAsteroid crater topBlacktron Chamberlain-class Capitulatorclutch topsfirst-generation planetary top starters
Jeremy McCreary

Jeremy McCreary

Lego spintop crafter

Lego Tops

Most of the videos here are extracted from my MOCs pages there and are working gizmos born of a fascination with gadgets and the science and engineering behind them. Technical LEGO® — my term for the fusion of LEGO® with STEM (science, technology, and math) subject matter — brings out my inner inventor/designer/engineer/toymaker like no other medium.

My work owes a great deal to the folks on my list of favorite builders. Their imagination and ingenuity never cease to amaze.