Big Disk Energy Post-event Report: Norwalk Havoc January 2019

Norwalk Havoc January 2019 is BDE's best showing so far. Officially, BDE went 4-2.

BDE was completed a full day in advance to make sure that I would get enough sleep before the event. I wanted to make sure that I would be able to stay calm and make good driving decisions in matches. I made sure that BDE's batteries were charged when I got to the event then waited for my first match.

BDE's first match was against Smee, a lifter robot with a large wedge in the front. I was not sure how BDE would fare against wedges, the whole idea behind BDE was to get a big enough weapon moment to do damage at lower weapon speeds, for good bite so I was hoping that I could get bite on the wedge but if my blade isn't sharp enough to dig into the wedge then it would deflect and just send me flying. BDE only has one blade that is pretty dull from all the hard hits BDE has dealt to opponents and the arena so I wan't sure how it would play out.


As expected, BDE did not get bite directly off of the wedge so there were just a few glancing blows until I got a hit in on the very back of the wedge, grabbing onto the back corner and breaking the wedge out of Smee. I was pretty excited after this match as it was BDE's first ever victory.

The next match was against a robot made by the same builder as Smee named Faster Owen. This was a unique robot that used a single weapon motor for translational movement by accelerating and decelerating the weapon. After talking with the builder, we realized that we both just wanted to see some high energy weapon on weapon hits. To make sure the weapons would collide, I inverted BDE into an overcutter by putting the tongue on the top of the robot and ran upside-down.


Sadly, we didn't get any direct hits because I couldn't find an angle to get to the blade without hitting a wheel on Faster Owen. I hit a wheel and the bar on Faster Owen was on the ground so it could no longer spin up. He asked for a second hit but that didn't help so Faster Owen was counted out.

BDE's next match was against Squishy. BDE has gone against Squishy at some point in every event so far. This time, Squishy's vertical module was functional and had a 1lb minibot called hockey puck. This match was going to be tough for BDE. My plan for this match was to ignore hockey puck and get as many hits in as possible on Squishy's vertical supports in an attempt to stop the weapon.


This match took a toll on BDE and was the first time the weapon has ever mechanically been stopped. There were a lot of intense hits from both robots here. It looks like I won a good amount of hits at first because the robots shot apart horizontally, rather than BDE being launched vertically if Squishy won the hits. The first hit flipped squishy upside down, which meant that he hit my blade downwards. These downward hits were hard enough to strip the 4 10-32 screws that hold the blade onto the hub off and disconnected the blade from the hub. The hubmotor still spun but the blade was dangling on my robot, held on by the tongue. After my blade was pulled off, the match became very one-sided as hockey puck could tee BDE up for Squishy to get better bite and launch me. The remainder of the match was me trying to keep the blade pointed towards squishy and avoiding electronics damage. I only lost one wheel in the remainder of the match.

After this fight I went over to see the damage I did to squishy. It turns out that I gave the vertical supports enough damage to cause some severe rubbing inside the motor. If Squishy's weapon had stopped in that match, it is quite likely that it would not have started again.

I got high centered on the tongue during this match because some of the hits rotated it back to the least optimal position. The next version of BDE will need a keyway or spline to prevent the tongue from rotating.

BDE was not out of the competition yet though, just pushed into the loser's bracket.

I was able to cross-thread some M5 screws into the holes holding the blade on to keep the weapon together for the remainder of the competition. I made a spare hub because this was a likely failure mode but I forgot it at WPI.

The next match was against Killer Taco, a beater bar robot made out of 3d printed rubber. I was relatively confident in this match but the weapon assembly did take some serious damage and I was worried that another weaker vertical hit could break the blade off again because I only had 4 cross-threaded M5s holding the blade on.


BDE's blade was no longer balanced after the Squishy match so getting up to speed was a little bit difficult from the vibrations but after getting to speed I was able to deal enough damage to stop Killer Taco's weapon and remove a side plate. The tongue was a little bit of a hindrance in this match because it was loosely spinning (I must have forgotten to tighten it or not tightened it enough). I nearly got high centered on a piece of debris from the arena but was saved by Brenda the brick (Brett was destroyed by So Ratchet). Later in the match, the weapon was stopped because the loctite holding my stator in place broke free and let the stator fall and rub on the weapon hub. I bought some green loctite that will work much better than the red loctite that was holding the stator on here.

I pulled the weapon assembly apart after this match and re-glued the stator. After a quick test and tightening the center bolt better so the tongue won't rotate, BDE was ready for the next fight.

The next fight for BDE was against So Ratchet, a horizontal midcutter that uses a box wrench as its blade. This robot has more reach than BDE and a higher blade so to get close I'll either have to tank a hit or get around the side of So Ratchet.


I was relatively confident in BDE's front armor so I went head first into So Ratchet. This approach didn't work too well as BDE just got hit to the side and chunks were removed from the frame. I got lucky with a side hit on one of the wheels then got a hit in hard enough to stop So Ratchet's weapon. With no weapon and one wheel, So Ratchet was unable to move. I gave So Ratchet a few more hits to see if the weapon would spin up then called it and So Ratchet got counted out.

BDE didn't take any damage that required repairs, but the frame did get a little torn up from that wrench. I just had to charge the batteries for the next match.

BDE's final match was against Wasp, another robot from WPI. Wasp is simple yet reliable as the weapon and drive rarely stop on this bot. My plan for this match was to bite into the titanium weapon supports and try to bend them inwards to stop Wasp's weapon. To do this, I needed to keep the weapon speed low and get solid bite.


I got three hits in on Wasp before my weapon was hit vertically, stripping the screws out of the hub again and letting the weapon fall off. I was kind of expecting this to happen because the weapon screws were still M5s cross-threaded into the stripped out 10-32 holes. At this point, BDE's weapon was retired for the event because I did not have the spare hub and there was no space on the hub to drill new holes. It looks like Wasp lost connection somehow (There was 2.4ghz interference at the event and Wasp was using a Hobbyking radio) and since Wasp was a robot from WPI, I tapped out strategically because BDE could not be repaired but Wasp could, giving our team a better chance of winning the event.

I wanted to do some drivetrain testing so I also put BDE, without a weapon, into the rumble at the end of the event. I just charged the lipos again then threw it in (on top of Roll Cake, to see it get launched)


Sawsloe came at BDE at the beginning of the match, sawing on the frame and doing some damage to one of the wheels. I sat in one spot going in circles until another WPI bot, Meili, came by and removed both wheels with one tap each. After that BDE just sat for the rest of the match while Meili and Roll Cake duked it out.

After the rumble I began to consider wheel guards on BDE because of how fast Meili took the wheels out.

Here is BDE post-event



I decided that the frame is going to be retired, as well as all of the components in the weapon module. The inner hub's tapped holes are stripped out and the outer housing was bent downwards after the Squishy fight because Squishy was upside down, giving downward hits.

BDE V4 is planned to compete at Motorama.


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