Build log
The MK2 drum was scrapped: too much mass for too little moment of inertia — the machined aluminum drum was heavy but stored too little energy for its weight, so it never justified its share of the 1500 g budget. The reliable brushless 4WD drivetrain and ELRS control stack lived on, spun off into the vertical-spinner CICD, which stores far more energy in a lighter 8 mm Hardox blade.
Successor to Lucille MK1 (retired after Iberanime), MK2 kept the Walking Dead identity and doubled down on the “brute force” thesis: a full-width front-mounted machined aluminum drum + 4WD brushless with planetary reduction. The drivetrain proved out, but the drum’s mass-to-MoI ratio killed the concept — the thesis shifted to a vertical spinner (see CICD).
Visual & Physical Profile
Multi-view (LucilleMK2 Assembly, rendered from Onshape)
Onshape’s Front view looks at the BACK of the robot — the CAD +Y axis points away from the drum, but in combat the drum side is the front (the business end that engages the opponent). The view filenames use Onshape’s axis labels (assembly-front-cad.png = Onshape Front = robot rear). Mentally flip when reading.
| CAD view | Filename | What’s in frame (robot-relative) |
|---|---|---|
| Isometric | assembly-isometric.png | Hero shot — drum across the combat front, weapon motor on the robot’s right upright |
| Top | assembly-top.png | Looking down — weapon motor + bracket toward the bottom of the image is the robot front; drive pulleys visible at the chassis sides |
| Bottom | assembly-bottom.png | Underside — chassis floor + four wheel positions; weapon motor pokes through at the top of frame (robot front) |
| Front (CAD) | assembly-front-cad.png | Looking at the robot’s REAR. Bottom cylinder = back bumper; orange uprights flank a flat top plate. |
| Back (CAD) | assembly-back-cad.png | Looking at the robot’s FRONT (drum-first). Big cylinder at top-center is the drum viewed end-on; bracket above it bolts the upright into the top plate. |
| Right (CAD) | assembly-right-cad.png | Looking at the robot’s LEFT side. Front + rear wheel with central drive pulley; small shaft stub at upper-right (combat-front side, no motor on this side). |
| Left (CAD) | assembly-left-cad.png | Looking at the robot’s RIGHT side. Same wheel layout; cylindrical body poking out upper-left is the D2830 weapon motor mounted to this upright. |
| Trimetric | assembly-trimetric.png | Alternative iso angle for layout discussion |
The MK2 chassis carries the orange/red TPU outer shell language from MK1 but expands to accommodate four wheels and a wide front drum. Layout (from CAD):
- Front: Machined aluminum horizontal drum, OD 60 mm, length ~130 mm, spanning between two orange TPU side towers. Drum runs on 2x MR688 bearings (8x16x5 mm sealed) seated in the towers, on an 8 mm shaft.
- Weapon motor: Mounted to the right upright (not perched on the top plate as the earliest concept render suggested). Single belt of measured length 225.366 mm (Onshape variable
#weapBelt) runs from the motor pulley down to a pulley on the outboard end of the drum shaft. Drum is still driven from one end only — far bearing is support. - Drive: One brushless drive motor per side, mounted between the front and rear wheels along the chassis side. Each motor drives both wheels on its side via twin equal pulleys (1:1) — see the chassis
Drivesketch. - Wheel pulleys: 42 mm pitch diameter (chassis
Drivesketch, DIAMETER constraint). - Wheels: 56x28 RZ knobby tires (the
56x28rz assemblyinstance in the LucilleMK2 assembly).
Internal Mechanics
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The Heart (Weapon System): A brushless D2830 1000kv motor (mounted on the right upright) drives the 60 mm OD machined aluminum drum via a single 225.366 mm belt to an outboard pulley on the drum shaft. The drum carries 3 replaceable teeth placed in a circular pattern, each fastened with M5 x 40 mm countersunk hex screws (from the Weapon part studio).
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The Muscle (Drive System): Four-wheel drive. 2x 2322 brushless motors with 25:1 planetary gearboxes (one per side) sit between the front and rear wheels along the chassis side, and each drives both wheels on its side through two equal-size belts to 42 mm pitch-diameter pulleys (1:1, no further reduction). Both wheels on a side spin in lockstep at the gearbox output speed.
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The Brains (Control): Carried over from MK1 — RadioMaster ER6 receiver on ExpressLRS 2.4GHz. See EdgeTX & ELRS Configuration.
Combat Strategy
MK2 trades MK1’s “feed-with-wedge” approach for direct horizontal drum engagement across the full front. There’s no separate wedge — the drum is the front face, spinning at high tip speed. The robot is harder to flank because both sides drive symmetrically, and the planetary gearboxes give meaningfully more pushing torque than the MK1 brushed gearmotors.
Replaceable teeth let MK2 stay competitive across a multi-match event without rebuilding the weapon: damaged teeth swap out in the pit instead of forcing a full drum reprint/remachine.