Bone Dead Robotics

March NHRL Post-Mortem

The last event Phenomenon competed at was March NHRL where it squared off against Emulsifier after a harrowing rush to get everything together. Though ultimately it lost due to the robot being turned off, I realized that the weapon system was ultimately still a big issue to work out. The pulley system from Vorion was effective and reliable from 4 years of honing but ultimately had limitations that kept the robot from implementing the full range of desired improvements, namely moving the lifter system internally. I believe the lifter is a crucial element that gives the Phenorion line a slight advantage over the normal tall vertical spinner so maintaining its usage was essential in any changes. For now the pulley system was again set aside and attention again turned to the hubmotor system.

Hubmotor Work

After disassembling the supposed dead hubmotor system, I was surprised to see the motor stator largely working still (a little dark on the windings, but I think that was the lighting) and reassembled it into a hub body for testing. Using a Castle Sidewinder 1/8 ESC from Vorion, the hubmotor base spin up very easily with no additional concerns. It was very surprising given the supposed death of it before the event, but for now it was functional so it would be investigated later.

Chassis Work

Another known issue with the hubmotor was the wires rubbing on the frame rail, so I used the CNC router to slightly increased the width of the channel they rest in so they could all lay flat against the aluminum.

It was also about this time that the U.S. tariffs on China were starting to ramp up so I tried fabricating the front frame rails and hubmotor endcaps as I did a few years ago to get some spares going. Using a combination of CNC router and 3D-printed jigs, the parts came together without too much work. Its good to be prepared!

After a little bit of work, Phenomenon was repaired and ready for some testing at the Hive!

Hubmotor Testing

After making our way down to the Hive, both Phenomenons did testing each sporting a Castle ESC on the weapon (alongside the very dangerous Deadrise). Neither ESC was tuned beyond stock settings just to get a read on their normal handling. The Sidewinder 1/8th ESC has a max continuous current of 90A which seemed to work fairly consistently on the hubmotors though it had a more gradual ramp of about 2 more seconds than the higher current Mamba Monster 2 likely because of the ESC trying to limit the current and avoid overheating. Even so, the hubmotor spun up fairly consistently over a 3 minute period which was a good sign. The Mamba Monster 2 ended up smoking the same reassembled hubmotor from earlier in this post likely due to its higher current rating and improper tuning.

Its importat to note that surface (or r/c car) ESCs are tuned to use inrunners which have 4 poles of magnets whereas aircraft or drone ESCs are designed around higher 14 pole motors. As a result, r/c car ESCs are less efficient in their startup power and create more stuttering and heat in an outrunner motor which is very bad for quick spinups. However, because of their generally higher current ratings this also means the ESC itself is very resilient so a much lower chance of electronic fires. In theory, a well-tuned sensored surface ESC would be incredibly effective at startup, but the sensorless controllers would always have some range of issue.

Thinking I had finally killed the previously dead hubmotor, I planned to swap a new hubmotor core into the robot once I had returned home.

Unfortunately, the long hoops showed their weakness as the lifting arm’s reach would gradually begin flexing them as they caught the edge of the hoop and pulled. Not a weakness that would especially cripple it during a fight, but the fear of the geometry potentially interfering with the weapon was still enough to warrant a change to shorter hoops in the future.

Later I discovered some of those big shots made the bearings a bit crunchy so I had to swap them out. A bit concerning considering the relatively little use they’ve received but the best to do now was replace them and keep it moving.

Preparation

Now that the Phenomenons were largely together, it was time to see exactly how the field was looking. The big names that initially drew my attention were Kablooey Tango, Super Obliterator 3000, Lil Lash, and Pepe Silvia. Pepe’s history with the team was well known from Motorama 2024, NHRL Teams, and Motorama 2025 so seeing it arrive was already worrying. Kablooey Tango brought back fond memories as it was defeated on the road to the team’s first ever golden dumpster in 2023 but it was clear that its power would be nothing to sneeze at. Super Obliterator 3000 and Lil Lash both put on impressive displays at the SCAR Big Bot Brawl in March so they seemed to be very impressive bots to look out for. Even other bot archetypes such as a hammersaw in HS1 and Huge-style big-wheeled vertical spinners in SMALL were important to consider as well. In total, I would have to deal with tall verts, horizontals, and hammersaws at this event. All of these machines are threats on their own, but then throw in the limitations of traveling across the country and suddenly spares/configurations become very limited very fast.

After some initial coercion, the same travel case that brought Fracas to the UK managed to house one Phenomenon and a few spare bits. It didn’t take long to figure out that between spares and robot both checked bags would quickly hit the 50lb weight limit and I only had two arms so only one robot would be going to the west coast. Though one robot and some spares used to the way about half a decade ago, since the rise of NHRL I’ve grown accustomed to having two machines around to offset 30lb repair times. Having one machine felt odd, but it also felt a good challenge to see how well I can maintain a machine under combat conditions and encouraged me to be judicious in my choices of tapping out if required.

Since this machine will also be competing at the June NHRL (and many other manufacturing resources were now beyond reach) I knew I would have to be more conservative than usual in conserving the robot, but I hoped I would still put on a good show. With spares and bot packed up, it was time to travel to California!

The Event

Pre-Fights

First of all, the Discovery Cube is an excellent venue. Not only was their ample pit space, but these enormous screens inside the area streamed fights and upcoming fights in the big and little arenas was supremely helpful to fans and builders alike. The Cube itself was also like a children’s science museum so they had lots of fantastic displays and demonstrations going on even outside of the robots; definitely a place worth its own trip!

There were a number of really interesting bots competing as well, this is only a small sampling of them that I could grab before the focus turned to fights

Eagle-eyed readers may say that HS1 looks familiar and they would be right! HS1 was built off the sold frames of the first version of Fracas! I felt a tinge of concern about losing to my old frame and/or protectiveness for it, but was also glad to see it still working and fighting. Daniel of Skorpios was getting great use of it!

After unpacking and getting through safety on Friday night, Phenomenon was looking ready for the main competition. One concern observed was the UHMW outriggers getting bent up slightly during transport meaning the robot didn’t move too well in safety. While this could be remedied by pushing down on them, did raise future concerns as a combat robot could easily bend these in even more crazy ways during a fight. More thoughts for later…

Competition

I would like to say Phenomenon’s run at RCL was eventful and glorious, but unfortunately it was brief and violent. Since Kablooey Tango was unable to compete, Super Obliterator 3000 fought Phenomenon for its first fight. Though this shot was quick and violent and did damage the machine, this ended up being Phenomenon’s last fight primarily due to issues with the hubmotor.

At the beginning of this match, Phenomenon’s hubmotor had issues cogging for maybe 10 or more seconds, causing some confusion as Phenomenon struggled to get going. After Obliterator delivered a solid shot which killed the drive on one side and knocked out the power of the robot, I noticed that the weapon itself on Phenomenon was smoking. Without any direct impact the weapon was already having issues, likely from the heat built up in the startup and perhaps some load as the robot was trying to self-right. Even so, that issue was critical and would take the longest to fix.

Post-Mortem

The 3mm AR500 top plate was pretty well bent from the hit, leaving the internals more exposed than I’d like (especially when fighting a Huge-style robot next) so I was already a little skeptical of using it again. It also turns out that the brittle copper wire broke a little after the switch. This was quickly fixed with a better wire later on. The drive motor’s magnets were crunched by the shot to the rear, but gradually that was bent back and replaced with a spare which ultimately allowed it to get back to working order. That being said, the hubmotor was still messed up and the robot was up in 3 fights so ultimately I forfeited to SMALL and accepted the lesson of the sad hubmotor as the main takeaway from the event.

While Phenomenon was able to test (and even practice spin-up in with a backup hubmotor) I elected not to fight it again to preserve the machine for June NHRL. A bummer on the combat front, but it also allowed a great time watching the fights and generally hanging out with other builders!

Reflections

Why go to RCL?

Though RCL happened to land on the same day as May NHRL, I elected to go to the further away event because combat robots are like Pokemon and the more varied gyms you go to the better chances you have to learn new things about your robot while meeting even more wonderful people. I’ll see the NHRL crew fairly soon with hopefully an even more solid robot to match, but this is a rare chance to see the Best of the West in their own place and spend time enjoying them in their home event. If you can travel to events outside your local region I encourage it and the memories made from it will agree!

Phenomenon Changes

Since the June event is the last NHRL event before the end-of-year crunch (there will be a break until September), it is imperative to make sure the robot is in top form to qualify. Though Vorion already qualified, its good to have two entries for the Grand Finals when rapid learning and better chances to get a good bracket spot are priceless. The hubmotor will likely go away briefly for more testing in the summer (as it has proven to be extremely troublesome all throughout winter) and the pulley system returning. Some radical re-working will have to be done to work around this limitation (especially to maintain configurations against such a powerful field) but if the strategy pays off then the cost will be well worth it.

Check back for more event reports and check out the build diaries of the robots!