BUILD REP RT:
Antweight – Motor City Massacre
● by Mike Jeffries
Motor City Massacre was a departure from my normal
design method. Most of my previous
bots have been constructed to have
the biggest weapon or thickest
armor I could fit within the weight
limit. With Motor City Massacre,
instead it was built around the
weapon concept with the knowledge
that once it was all together and
working, a substantial amount of
weight would need to be removed.
Motor City Massacre was
designed to be made entirely on a
waterjet with commercially available
hardware used to connect the
various panels together. The main
structure uses a mixture of hex
standoffs and nutstrip (available at
kitbots.com) to hold the flat panels
in place. Assembly went very fast,
however, it was quickly becoming
apparent that the weight issues
were going to be severe.
After the initial build was
completed, it was obvious that
drastic measures were needed to
get Motor City Massacre under
weight. The 1/32” steel armor that
was supposed to be used on both
sides was removed from the side
covering the servo. This switch
meant that none of the electrical
system could be placed in that half
of the robot.
Buried beneath the tangle of
wires are two Fingertech TinyESCs,
two 22.2:1 Silver Spark gearmotors,
a HobbyKing R410 receiver, a
battery elimination circuit for servo
power, and a custom hex wrench
operated power switch.
Motor City Massacre has
already attended its first event. It
was driven to a 3rd place finish at
Dragon*Con Microbattles without
the use of the grabbing claw since
the mount had not yet
been finished. During
testing after the event,
I noticed that the robot
was bouncing at high
speeds. I found that the
Lite Flite wheels were
not particularly round
and were the source of
the bounce. To correct
this issue, I put a 3 mm
FIGURE 1. Initial CAD model
of Motor City Massacre.
FIGURE 2. A partially assembled Motor
City Massacre with the main assembly
techniques on display.
FIGURE 3. The armored portion
of the chassis is packed to the
point of being nearly solid.
SERVO 03.2012 35
