SERVO 10.2014 21
work out in practice? Really well!
Weta took first place at Clash of the
Bots. We got a bye in the first round,
and the faster beater and sharpened
teeth made quick work of Ricola and
Polymer (a pair of very similar bots to
Weta) before meeting Weta’s arch
rival, Grande Tambor.
Weta got the best of the early
hits, then a tooth-to-tooth hit snapped
the drive belt in Weta but also killed
Grande Tambor’s drum. Weta had the
edge in the resulting pushy contest
and won by a judge’s decision. We
never had a belt break in Weta
before, and found when getting back
to the pits both the weapon axle and
motor shafts were also bent slightly,
plus one tooth of the beater was
partially pulled out.
We had spares for the belt, axle,
and motor, and the bent tooth was
ground down so it didn’t catch the
floor when the beater was spinning.
In the finals, we met Grande
Tambor again. Weta dominated for
the first minute and a half, then the
loose tooth came out of Weta’s
beater. This turned the tide and
Grande got a couple of great hits in
Weta got a close judge’s decision to
win the Beetleweight class.
The damage to the beater bar
(Figure 11) included a couple of nice
neat chunks removed, one lost tooth,
and another one bent. The LiPo
battery was also found to have puffed
up. The beater bar can be repaired
and used as a spare for future
The new motors were a big
success but are now no longer
produced. I have a couple of spares,
so it shouldn’t be a problem for the
next event, but the hunt is back on
for a suitable replacement.
A wider 9 mm belt should fit, so
that might prevent future belt failures,
but it might also increase problems
with the motor shafts. The puffed up
LiPo shows that even the 70C version
of the Thunderpower 850 mAh packs
is not up to the task. So, the main
change for the next event will be
squeezing in a 1,300 mAh 70C pack
(Figure 12). That should allow Weta
to fight hard for a full three minutes.
I’ve got the weight and I think I can
modify the chassis to let it fit.
My two 3D printed bots — Swiss
Wedge of Doom and Bleuhh Cheese
— both competed at Clash of the
Bots. Swiss Wedge of Doom went 0-2,
mostly due to problems with it getting
high-sided on its own wedge or
getting the wedge stuck in the arena.
On the plus side, the tracks worked
well and survived undamaged.
Bleuhh Cheese proved fast and
maneuverable, but lacked a feature on
its wedge that would let it push its
opponents. A lack of clearance for the
wheels meant that when the foam
wheels got cut up a bit, they jammed.
However, Bleuhh Cheese got third
place out of a field of eight.
The 3D printed chassis on both
bots worked better than expected.
Chunks got cut out of the surface
layers but they held together well
(Figure 13). Both will get improved
3D printed chassis for the next event.
The wider Saifu Antweight
(recently described in a SERVO article)
also did well. The wider drum was
much more effective, and the bot
finished fourth. SV