Blunder V2 – Oct & Nov Events

During the months of October and November, Blunder V2 attended 3 events:

NHRL October 2025
September Smackdown at RCE 2025
NHRL November 2025

Changes

Over summer break in 2025, I took the time to make major improvements to Blunder. My performances at February and April 2025 NHRLs were hindered by a few design weaknesses.

The most dramatic change was form factor. Shifting from a longer chassis to a wider chassis provided more stability against gyroscopic forces and allowed me to move the shufflers closer to the front. The shorter drivebase reduces the effect of scrubbing during turns and moves the center of mass closer to the front of the robot.

One of the biggest challenges across Version 1 was getting consistent traction. The first design, shown in white, utilized Reoflex 30A urethane for traction. Unfortunately, this version did not have enough traction and the robot handled as if it was driving on ice. Combined with the extreme wear, this design was phased out extremely quickly. The second design, shown in red, utilizes 1.6mm thick Grade 5 Titanium “cleats” to grip into the wood floors for greater traction. However, due to the low hardness of Ti at 35 HRC, the points of the cleats wore away in under 6 minutes of driving.

Designs 2 and 3 both utilized laser-cut cleats which were inserted into a 3D printed 98A TPU “foot”. The print was paused at the correct layer, the cleats inserted, and the print resumed to close over and secure the cleats.

Design 3 utilized dual-layer 1095 Spring Steel for its increased hardness, and a balance of thickness for wear-resistance and increased traction on the wood. Moving to the spring steel also came along with changing the interlocking method, creating a larger area allowing for a larger range of tolerances on the laser-cut parts.

Forgive the poor quality picture, but the traction provided by the spring steel cannot be understated. With only a slight tap, the foot dug into the wood and was able to hold itself in the air.

The main reason I was able to compact the robot was changing the shufflers from direct drive to indirect gear drive. This created greater internal space and allowed me to move the entire assembly forwards as it was no longer constrained by the sizes of the motors internally. This change required custom machined shafts for the feet and bearings to ride on, which were made from 6061 Aluminum on a Haas VM2 and toleranced for a slight clearance fit on the bearings.

These gears proved to be slightly more difficult than anticipated, and the events covered in this post were plagued with drive reliability issues.

While the weapon assembly had proved to be extremely durable, the ESC driving the weapon motor had proven to be a challenge. Driving a BadAss 2814 motor, a larger size motor than most beetleweights, the first two ESCs used were not up to the task. The NeutronRC 70a would overheat in less than a minute even with a heatsink, and the VGood 80a had desync issues across both copies. For October NHRL, I switched to the TBS Lucid 90a. This was an extremely overkill choice, as this ESC is now known to run even larger setups on some 12lb robots. At the time, however, it was fairly new and untested.

Having tested the robot for the first time just two days before the first event, I was confident the bot functioned but had no sense of its durability.