Post-Mortem from Motorama Robot Conflict

Mega Conceptual Chaos:

Everything was set to go minus hot-gluing the receiver leads and taping/shock mounting. I added some foam and rubber to the battery mounts I had to give extra cushion if the bot was jarred. The electronics I just ended up cramming in the rear, and it worked out reasonably well.

After the first fight win against Big Black Richard, I suffered some unexpected damage. BBR had bent the harder grade threaded rod on the one side of drive, making it a bit wobbly. I also noticed when I took off the wheels that the gearbox’s output tabs had started to break off. Very strange why it was doing that. Only theory I could produce was that the clearances I had designed were a bit tight and that the pressure was enough that a minor amount of shock would sheer them. I also realized my steering was backwards, but that was easily remedied by switching the ESCs to the opposite motor.

My second fight was against Big Ripto.. joy! I actually wanted to fight Ripto as I wanted to see how the frame would hold up against him and Triggo. Tried to see if I could outdrive Ripto for a hot second the realized it wouldn’t work, he then caught the angled side of the plow and sent CC about 8 feet in the air. The bot landed, had a small twitch or three, and everything stopped. Went to check on it post match and found that the motors had seized up on the hit. The Banebots ESCs were completely fine.

After swapping motors, I noticed slightly more damage on the second set of gearboxes I had installed before the previous fight, but not enough to completely ruin them. I opened up the output area on the wheels with a dremel and hoped this would help.

I drew Battlebots Season 2 Champion Ray Billings, and his 30lb creation, Soylent Green. I was able to do a bit more driving around before making contact with his weapon. Upon contact, the plow rocketed away from the robot, but thankfully I was able to still drive. CC was now a wheelie machine, but I had one moment where I was able to get around back and try to push around Soylent Green, but it didn’t work out so well. Another hard hit to the frame and I was once again dead in the water. Lo and behold, two more seized motors. I inspected why the wedge removed itself, and it was ripped clean from the welds on the front arms.

So, CC ended up 1-2.  If I am to continue this design, a few things will have to change..

– Different drivetrain, most likely Dewuts or a P60 gearbox setup (brushless?)
– Thicker AR400.. or at least better supported framing.. and THICK AF welds! The fact that Ripto took a chunk out of 1/4″ AR400 really shocked me.
– The wheels can stay, and be broached. Tread will need to change.

Most likely, this bot will take a hiatus for now…

Wedding Gift:

The steel for the sportsman arrived Friday while I was out on my run. After getting settled in, there was some minor filing to do to get the parts to fit to weld. What became a problem that I am not used to is the amount of tolerance needed for parts to move smoothly on a round shaft. After tacking, test fitting, and finishing off the welds, the arm became stuck on the shaft, and needed to be removed by a press. Thankfully, between Kyle and Zac, we resolved that problem and I went to work on opening up the shaft holes on the weapon arm.  (I have since bought a more robust rotary tool)

After getting the shaft “sloppy” enough, I was able to get everything  on the shaft and confirm that the system moved well once the keyways were in. I finished cycling the new batteries, and put the weapon assembly back together on the frame. After getting everything back together, I realized that I must have put one of the bearing blocks on backward, as suddenly I was a chain link’s length too far on the second stage; it was going to be a bit loose. Jim F graciously offered to help work on the chain to get it to the right length while I went to go announce the first set of fights, but found that I would need a half link to get everything to work right. I would have to gamble on making it to Sunday and getting to Lowes after the fights were done for the day to get the half link if it existed there.

First fight was against Translationally Inconsistent. Pretty much knew the outcome from the beginning. The hammer worked okay, but there was slipping on the chain due to the extra link in the second stage gearing. Thankfully the gearing helped to get the bot back on its feet multiple times throughout the match and I made it the full three minutes.

Next fight was against Art of Flipping. I had gotten the steering worked out for the fight and they seemed to have issues keeping their drive going. I was able to land a few hits despite the chains slipping even more.

I found out later on I’d have the last fight of the night against my good friend Josh and Swordfish II. Charged the batteries and hoped for the best! I ended up getting owned as Swordfish’s design worked well against my bot. His auger fit in the gaps on the rear side of the frame, and he stuck on me like glue. The hammer was slipping much, much more during this match.

The next day, Al happened to have a half link with him as he had chain parts for Joe and Coup De Gracey. I spent the time trying to troubleshoot the weapon arm after I got the half link on. Even with the chain now fitting, there was still some slipping going on. I conferred with Charles about the Dewut, and got his confirmation that the clutch was okay, and that it was truly set in low gear. The Dewalt motor I picked up was on eBay by a Dewalt parts seller that had a manufacturer refurbished motor. Apparently you run a risk by buying refurbished or anything other than new with sellers sometimes just wirebrushing the motor and calling it “fixed”

I’ll take apart the Dewut in a few days and make sure the pinion is glued in place with retaining compound. Don’t think silver solder will work in this case, but I’d be willing to try. Here’s the few seconds it worked in the rumble…

Final Thoughts:

I think I’ll run with the sportsman for now since it’s the less costly of the two to maintain right now. I know I need to lean out the design, and now that my original plans got scrapped, I can easily re-design this frame to be more efficient, and hopefully fit inside the weapon arm. I think for now, I’ll stick with the power wheels gearboxes, but I’ll find a way to reinforce them better so that there’s no way the motor is impacted.

Now that I’ve gotten a hang with the CAD programs again, I’d like to finalize designing a purely fun 12lb brick using some old 7:1 Mabuchis that I’ve had for about a decade (and gear them down some more). The thought is to use some thick U channel (either steel or aluminum) facing inward for structural integrity, and some thick UHMW side rails, and beefy Titanium shafts. The sole purpose of the bot is to get hit to the ceiling and keep taking hits to have the crowd enjoy.. Kinda like Homer Simpson when he became a boxer. We’ll see.


Jon is a recreational runner of many, many distances, a music lover at heart, seasoned veteran of combat robot fighting, and a frugal (stingy) shopper of everything. He's a proud husband, and clean and sober since 2012.

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