After the October event Phenomenon was in good shape. The only repair to be made was to replace the ground wire on the switch. Its relative success in its fights (especially against Touro Feather) indicated a good setup for Finals. Because of this, efforts were turned to Vorion leading up to the event.

Originally Vorion was supposed to be left as a more simple, stalwart machine with known technology while Phenomenon was supposed to be the innovating machine with the hubmotor being at the center of it. Though in its history of first development last year in June, severe setback at Finals 2024, then never really got working through to May 2025, it was set aside as an ultimately unreliable system for a full 30lb weapon. In June 2025 Phenomenon was brought back to a pulley system where it stayed through to the end of the year in order to qualify. Since Phenomenon had become the steady machine with nothing to change, it was time to invert roles and do testing on Vorion instead.

Vorion Preparation

JCR Zombox

The first big update on the line for the robots was the implementation of the JCR Zomboxes. I provided input to Seth on what would be a good drive option for the 30lbers and after some back and forth this is what came together. The original system used in Phenomenon/Vorion is a single stage 9:1 Versaplanetary with a 650kv 3520 (stator-size) motor. After working with Matt Bores of Bots FC (Emulsifier) the gearboxes were refined and became a very reliable drive option on all of the 30lb entries. However, due to the additional modifications needed it wasn’t an easy solution. The hope was that the Zomboxes’ combat-focused design paired with a 750kv 4238 (rotor size) motor would provide a great area of improvement.

It took some work turning down the shafts from the 5mm native to the motors to the 4mm (or 3.175mm bores if I messed up) bore of the gearbox pinion but once assembled it was clear by size and weight that this had great potential. The only downside was the 5.8:1 reduction in the Zombox compared to the 9:1 of the Versaplanetary also mixed with the higher 750kv motor meant that the theoretical top speed was ~30mph which was nearly double the top speed of the current setup. While this may be positive on the surface, this was a great concern as this also meant more current draw and higher heat build-up due to the motor never getting to its peak performance before the having to slow down again to move in a different direction. The extent of this concern was unknown so it was time for testing.

To test out the new gearmotors it was first a bench test followed by a drive test. On the bench the gearbox was getting warm without load which was concerning. Quick disassembly revealed no binding in the gearbox so one could only assume there was binding in the motor. My theory is the shaft of the motors was bent slightly when pressing the gear to the shaft. Since there wasn’t a way to easily remedy this, the tests proceeded.

These were placed in Phenomenon which ran around outside for 3 mins mirroring combat activity (lots of back and forth movement) then measured with temperature. After a few rounds of testing the temperature averaged ~140F which was very high. While the robot did not lose functionality, it could prove to be a fatal flaw especially against flame bots like Kazaa Lite and the overall lifetime of the motors as the heat weakens the magnetism.

To fix this issue, the motor was replaced with a 4258 500kv motor. The larger size of the motor and a lower kv rating meant that the target speed decreased to 16mph, the same as the Versaplanetary combo. Once again I noticed an issue on the table top where, despite low resistance in the gearbox, there was heat buildup. Once again, it seems a slight bend in the shaft formed by pressing the gears seems to have formed some resistance in the motor. This was confirmed by a feeling of high and low spots when rotating the motor. I’ll definitely have to make better jigs or invest in the proper motors for these in the future. It was suboptimal but it was time to focus on the rest of the robot.

Robot Preparation

Once a new set of parts arrived it was time to assemble the chassis. Since this is essentially the same chassis as the others, the assembly became pretty routine. While I had ambitions to make Vorion much more unique from Phenomenon, the setbacks at the beginning of the year from the hubmotor meant at the end of the year the designs had to match to ensure higher reliability. The major difference between the two became Vorion running the Zomboxes while Phenomenon kept the Versaplanetaries. It was a bit of an experiment but ultimately I was confident in both as drive solutions.

After a bit of testing at the Hive, the robots were mostly cleared for function. There were a few tweaks to iron out since they were new but otherwise were good enough to set aside and return to later on.

A few weeks out from the competition, spare parts began to be made, namely fork mounts, lifter mounts, and lifter tips.

The last part left was stickers! Since the claws are supposed to be oriented to each other I left little strips between them to maintain the shape but trimmed off the rest of the film to make it look a bit cleaner

Electrical Woes

During testing at the Hive, I noticed an issue with the weapon creating feedback in the system. Through the sound of an audible “whine” as the motor shaft rotated it was clear that there was some sort of back emf being generated by the motor’s changing magnetic field. In practice this meant as it the weapon spun up the ESC was having issues commutating and it sounded like it was fighting itself. After <1min of driving the drive would die on one side and the weapon spins down. Despite full disassembly at the Hive to find knicks in the wire harness, no breaks were found so it would need to be further analyzed at home.

First I checked to confirm any continuity between the motor and main ground. Next the motor body itself was checked. For inrunners, the faceplate has mounting bolts that run straight through to the main body of the motor. If the mounting bolts went to the bottom of this section to the stator this can create continuity with the chassis. After verifying the bolts were not doing this I then tested directly down to the stator, then the shaft (which should also be conductive, as the ball bearings link the rotor to the stator), then the can body itself (which should be non-conductive due to anodized body). I found that for some reason if I were to hold the motor in the air in my hand it was fine, but as soon as it touched the body of the frame at any point (can body, backplate, shaft, etc) I could hear the commutation.

Ultimately, the only solution left was to change out the weapon controller with the last spare on-hand which miraculously fixed the problem. The running theory was there is a internal short in the controller that allowed the normally isolated circuits between the motor and power to short. Since the Mamba Monster 2 controllers are potted (common in r/c cars to avoid debris from dirt/water) it would be great effort to figure it out so for now it remains a mystery. Since there were the 3 other identical systems working perfectly fine I had to assume this was a statistical rarity. This report will serve as a data point to refer to later if it happens again.

Tires & Cleats

The last little issue that I was running into was wheel traction. On a 2WD robot, losing any traction in a fight is a death sentence as your margin for error is very small. The first thought was to try out cleats due to them doing a great job in other robots like Maximizer and Buzzzzkill who are also 2WD robots that rely heavily on drive. The ones on Phenomenon were old ones made from mild steel and the ones on Vorion were routed from Grade 5 Titanium.

The second tip was to use techniques from past history in r/c car racing: cleaning the tires. I noticed a build up of paint from the Hive’s floor which slowly made the driving on Phenomenon worse over time. The NHRL floors are painted too so this was likely building up there too even though I didn’t notice it. With a bit of acetone and a paper towel, the paint comes off the urethane tread pretty quickly leading to a much grippier surface. This will become part of the standard pre-fight procedure.

With that all 4 bots were assembled and packed for travel!

Competition

Round 1

Phenomenon v. Banguela

The first matchup for the day was Phenomenon vs Banguela from Uairrior. This robot is built very firmly much like its larger sibling Black Dragon from Battlebots. They were having drive issues but there weapon was very solid so it was going to be a close fight.

Fortunately, Phenomenon won! The big moment was the weapon breaking in an exchange. Though both primary weapons went down midway through the fight, Phenomenon’s lifter was the deciding factor in the exact same way as it was against Touro in October. After talking with the team, their weapon was 4340 that was supposedly hardened to 48HRC. According to engineering charts this would be much more resistant to a brittle failure, so perhaps it was much harder. The H13 48HRC disk of Phenomenon is really good at breaking beaters as its able to exert a lot of pressure on the contact point of the beater. This, as well as lower cost of manufacturing, make disks my preferred archetype. Overall the team was a great sport and Phenomenon started the event strong at 1-0.

Vorion vs Undertaker

Vorion’s previous fight of 2025 was against Undertaker back in February. Back then Vorion’s radio system was faulty so the robot was going in and out of control even at the beginning of the fight. Now that the radio issue was fixed with Phenomenon earlier in the year, the big focus was on Undertaker. This robot was newer and much stronger than the first version. The biggest fear was the long forks attached to the front of the machine. Not only were these forks already far longer than the ones on Vorion, but beater bars and drums are Vorion’s worst archetype to fight. Due to the heavy reliance on the front forks to feed the opponent into the weapon and maintain robot balance, beater bars and drums’ ability to bend the forks becomes incredibly debilitating very quickly. Therefore, even if Vorion was able to evade or break the large forks up front, all it takes is a bite from Undertaker’s weapon to bend the forks and throw the robot in the air.

That was exactly what happened. In short, Vorion couldn’t do anything to Undertaker and Undertaker’s beater bar did very similar damage to the frame. Even more incredibly, Undertaker managed to once again damage the lifter gearbox despite being moved out of harm’s way. This may take some more investigation to see if anything else was damaged along the way that could hint to how it failed, but it does give some data for the future. Vorion loses, 0-1.

After entrusting it to my new teammates for disassembly(pulled from Blue Marlin), the robot was left as a spare to use for the rest of the machines. The chassis is still repairable, but due to the speed of the competition it was critical to prioritize time.

Round 2

Vorion vs BYE

Because of the way the bracket worked out, the winner of Vorion v. Undertaker would fight the high-ranking flaming multi-bot KaZaA Lite. Due to its high seeding, KaZaA received a bye which then flowed down to the loser of the fight. With the loss, Vorion receives the bye and continues to round 3. Vorion, 1-1

Phenomenon vs Jubileu

Phenomenon has historically done very well against horizontals and for good reason: it has a large, thick wedge and a stout weapon assembly made to uppercut the bars. With the previous success it felt like a generally good draw.

The lifter giveth and the lifter taketh away. While early exchanges favored Phenomenon, the power of the lifter and shorter body with the wedge meant the robot flipped itself around the weapon making it get stuck twice and losing precious self-righting time allowing Jubileu to recompose and strike the rear plate of Phenomenon. The shot crumpled the left drive side and manage to kill the drive controller for the right drive side leading to complete immobilization. After a bit of work, the backplate was removed and the broken parts removed from the chassis. There may be some change to the exponential control of the lifting arm for moments like these, but ultimately this is just an unlucky break that most of the time doesn’t happen. Since Jubileu is also from Uairrior I shared a Phenomenon backplate with them the same way they shared Banguela’s beater bar. In Phenomenon’s war against Brazil it draws 1-1.

Round 3

Vorion vs Lil Lash

This was the fight I was probably most excited about all day. These robots are similar basic idea, but very different ways of going about it. While Vorion had longer forks than Lil Lash, its larger weapon risked issues with losing control due to gyroscopic procession.

In reality the fight was far less exciting than hoped. After an initial juke, the pinion on one drive side slipped causing it to lose drive on one side. From there it was pushed onto the arena wall in one of the worst ways possible so the house bot was unable to free it leading to knockout. All in all, not much wrong with the robot again as either a quick motor swap (or buying the preassembled motors from JCR) would likely solve the pinion issue and simply avoiding the wall would solve the stuck issue. Even so, Vorion is out with a record of 1-2 (0-2 in actual fights).

Kudos to Matt Vasquez for expertly sniping the lifting chain and horn and giving them to kids in the crowd as souvenirs!

Phenomenon vs Termigator

Phenomenon’s last fight was against Termigator, a incredibly wide and controlled drum bot. As noted earlier, drum bots are a weakness for my fork-heavy design so as this fight was announced I deflated internally. While I knew the forks could defend against the drum if lined up perfectly, Termigator’s speed and wide drum meant it would likely get a good angle on the forks sooner than later and bend them. Using the same configuration as used against Touro in October, Phenomenon prepared to fight.

Unfortunately that was what happened, more or less. The heavily chewed up arena floor meant the forks got stuck relatively quickly leading to free hits by Termigator. Once Termigator struck the side of the forks and bent them up it was downhill from there. While none of the internals were damaged and the robot likely could be rebuilt and run again, the lessons were learned. Phenomenon is knocked out at 1-2.

Conclusion

Despite the result of the tournament, there was very little “heavy” damage to the machines. The most “expensive” damage was from the fight against Jubileu with one dead controller and motor. At a high level this is a good outcome as this means the effort to make Phenomenon more durable over time was successful. With all of these parts still functional there will likely be more prototyping in the offseason. The cleats were functional but definitely required better mounting practice if used again. The output shafts of the Versaplanetary gearboxes were bent but still freely rotating so they could likely be mated with new output shafts (likely with the 1/2″ hex to match the output of the Zomboxes) and reused. That being said, since the Versaplanetary gearboxes seem to be removed and discontinued they can’t be trusted in the long-term so likely more Zomboxes are inbound.

Looking Forward

My friend and commentator Ricky noted how it seems once something goes wrong on these robots it doesn’t take long for it to spiral into a problem; its failure modes are not “robust.” It was an excellent point as the second the forks or outriggers were bent the robot was instantly neutralized; weapon reach and drive stability plummeted. Additionally, weapon motor reliability seemed to be an issue as the weapon went down from its own impacts to others so there will likely be work there. Therefore the main things to change are:

• 4WD
• Fork Geometry
• Weapon Motor Relaibility

While the other two will come in later updates, the 4WD change can be discussed briefly below.

While Phenomenon has the ability to lift up its front if the coefficient of friction is high (such as clean wheels at the beginning of the fight), as it decreases over time due to debris attaching to the wheel or damage to the wheel itself the driving ability rapidly decreases as the majority of the force wants to go through the outriggers instead of the drive wheels. This temperamental condition is how Phenomenon can go from gliding across the arena in the first minute to nearly limping the rest of the fight. Cleats mitigate this some by ensuring a high coefficient of friction but because they are less resilient than the rubber wheels they can become a liability (such as in the fight against Termigator where they were bent and nearly broke the drive side). Emulsifier has begun to use cleats more for this benefit, but the risk has hurt them before as well.

Naturally the best move is to put a front wheel directly below the center of mass to maintain movement. However, the weapon must also be shifted slightly further forward to avoid lift in the front as it did against MegatRon after losing its forks. These slight changes will be tested at the Hive in the beginning of the year and, depending on how they work out, may lead to another update of V2 (V2.3) or a new version entirely. Either way, there will be many hours in Solidworks and 3D printed tests awaiting Phenomenon before any returns to NHRL.

2026

For now, Vorion will be retired. Having two 30lb entries is a lot and having two very similar entries isn’t very dynamic. The name will likely be reused in some capacity, but the legacy of Phenomenon being one of only 3x 30lbers to compete at all 5x NHRL 30lb World Championships to date is one to honor and remember. Instead, new 3lb and 12lb entries will be made patterned off of the same vert-lifter archetype that Phenomenon is. With the rise of events like Hive Hysteria, GSCRL, and others it makes a lot sense to give more effort to these classes and provide a bit of rest from the 30lb weight class. While all efforts will be pushed to qualify Phenomenon first and foremost, it is more engaging to try the design archetype in different classes and see what lessons may be learned from it. There’s always a chance for other machines to show up but time will tell.

On to 2026!