Norwalk Havoc May 2021: Scale Model Testing Your BattleBots in Nightmare Mode

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It’s time for robots once again! I think what I’m planning on doing from here is, barring one or two more Summer of Ven posts (which is now well into the Fall and Winter of Ven anyhow) I’m going to begin transitioning towards Overhaul, finally.

You see, a major over-winter project of mine was trying to get Overhaul 1 up and running again, at least walking. There was a good bit of fabrication and “What in the everloving fuck did we do here…” reverse engineering your own work from 6-odd years ago. While it’s cool enough in its own right, I’m planning on using that to move towards the long-overdue Overhaul 3 design and build series. I mean, y’all already know what the bot looks like since it’s appeared on here by now, but there was a lot of translation from 30haul’s geometry to the full size bot.

But in the mean time, let’s talk 30haul. Recall the “lessons learned” of the previous March Norwalk post

I’m revising the Snout design to be stiffer on the corners, trading the internal webs for a U-shaped bottom truss shape. The metal is rigid enough on this scale that I don’t think the center webs contributed much.

Next up, after watching enough Battlebots and seeing enough matches at this point, I’m going to make 30Haul an entry in the “fork wars” currently ravaging the combat robot landscape. The joke is that ground-scraping forks grew a foot over the course of the 2020 season, as one of the only ways to ensure a vertical spinner doesn’t get under you, is to get under it first. Keeping the opponent away and under control is just as essential as being able to take (or deliver) the hit…

I’m also beginning to like the Vex wheels less and less, because while they initially offered the bouncy compliance I was looking for, once they start disintegrating, they become more liabilities. The spokes will tear through, leaving the big gaps in the perimeter that then flap in the wind. I decided to try and find some thick foam rubber I can use to make at-scale foamy wheels, not dissimilar to Overhaul’s.

Before any of that can happen, though, I had to have a 30haul that was functional. The damage from March wasn’t that bad in the grand scheme of things, but in the name of thoroughness I decided to completely take the bot apart and remanufacture it to address some of the frame damage and retighten the motor screws, among other tasks.

So here’s 30haul in a pile of itself! I planned to repair the frame as much as I could and keep it around as a backup, because…

Prior to March, I commissioned an entire new chassis to be machined by Wedge Industries. I figured as long as I actually had new 30haul parts, why not just move the bot to the new chassis and keep the old one as the “Just in case…”

To save some expense, I had Alex pound out only the net shape geometry. Since I have my own capabilities, I save some on the machine time and setup when it comes to tapping and countersinking, among other operations. So the first order of business with this new chassis was just chucking the ol’ spiral-flute 1/4-20 into my drill and having a pleasant time.

To the old frame, I repaired the damaged threads in multiple frame rails with threadlocked Helicoil inserts. The rear bulkhead shown here was actually quite bent up from the Ripto match. I used my arbor press to straighten it using some cleverly placed spacers.

Original chassis coming back together with an added weight-shaving pocket that I designed into the one that was sent out for manufacturing. There’s nothing over this area worth hitting really, so no reason to have the weight.

And the original chassis fully repaired and assembled!

The new chassis needed the end-tap holes put in. The way to do this would be to set them up at an angle on the drill press, but I was confident enough in my drill bit rodeo skills such that I just clamped everything together on the bench and hit the front (angled irritatingly – that got designed out of Overhaul 3) bulkhead holes. The rear set I piloted and threaded in one screw before finishing the rest on the drill press.

New chassis fully assembled and ready for population.

Next item on the agenda was to make some wheels. I said earlier that I wanted actual foam rubber wheels for 30haul now to get away from the Vex wheels, as while they did offer the compliance I was looking for, their failure mode was becoming big rubber flaps.

I looked into a few difference sources of “rigid” foam rubber, such as anti-fatigue floor mats and similar. Ultimately McMaster-Carr came to the rescue with a sheet of natural rubber foam – the nice thing was, in the time I had, it just offered a compression/deflection rating in PSI so it was easier to visualize how much give it would have.

To manufacture the wheels, I initially tried to find a hole saw set where I could get a 4 inch and a 1 inch saw on the same arbor. Maybe this was possible in the ol’ glory days of Comedy Central Sports Presents BattleBots™ as I recall a few builders’ reports saying they mounted two hole saws on one arbor to cut washers (e.g. for clutches, spacers, and wheels as well). But these days the consumer systems seem to have evolved and specialized, so the smaller sizes of hole saw usually have direct screw-on mandrels and larger ones have the pin locking ones.

I ended up picking up probably the most horrible Chinesium hole saw set Amazon had to offer in the hopes that it had generic mandrels, but alas, I found that the D-bore of the saws were different sizes as well. Either way, I found out that just hole sawing into the rubber wasn’t bad for alignment anyway. It’ll become round once I do enough burnouts!

I drilled these wheels using the Vex hubs as a template and put the same hole pattern into them.

For now, I made only the two (well, four…) front wheel assemblies to alleviate the worst of the wheel compression issues. What would happen is the Vex wheels would flatten between spokes and then bounce up once it reaches a spoke, and it actually made the bot drive a little bouncy as a result. These are a good deal lighter than the Vex wheels as well.

Hey, no use in spending too much time making wheels if I don’t have the rest of the bot yet. So off we go with populating the new chassis!

While doing so, I re-discovered a problem that might have prevented 30haul from being able to lift much. Recall that I had to step down from a 3-stage P60 gearbox to a 2-stage because the torque of the 3-stage type was rounding off its own output spline. This design stands in contrast with Overhaul 2 (and 3) because 30haul doesn’t have an intermediate gear stage, the lift motor directly fiddles the Big Gear.

I noticed the motor would bind up whenever I spun the gearbox one way. It turns out the output spline on this gearbox was deformed helically in a fashion that positive torque (lift) tended to shove the carrier off the spline, causing it to bind up like a clutch plate against the first stage.

Well, to repair this, I’d just have to replace the output shaft. Trouble with that? To clear the Big Gear and lifter forks, I had to position the motor farther away from the sidewall with the support bearing. Namely, about 2 inches. The stock Banebots P61 gearbox has a 1.5″ shaft.

I was at a juncture where waiting for Banebots shafts to be ordered would mean delaying the bot’s assembly into the week of the event, which I really didn’t feel like doing. So I decided to make a shaft extender, just a turned piece of 7075 rod with a 1/2″ socket on one side and 1/2″ stub on the other, long enough to bridge the gap. A 10-32 screw goes through the middle into the end-tapped P61 shaft.

Here’s what it looks like installed, along with the rest of the motors. Again, the motivating factor here was just to be able to reach that outer support bearing with a stock-length P61 shaft, of which I have plenty of spares.

Wheels loaded on and chassis off the ground now. I like these front wheels already – they don’t cause the front of the bot to sag at all, but are still very bouncy. Boy I wish someone made 3-4″ thick chunks of this stuff!

I finished assembling the bot and put it in “Sportsman Mode” since I didn’t yet know who I was fighting at the time – I’ll change things once I get there. In the time between this and leaving for the event, I put together what I think are the last two 6-fet Brushless Rages left and readied some other spare parts.

You see, by checking out the registration roster, I found out that every other 30lber was a vertical spinner of some sort. Whether disc or drum, this tournament was going to be absolutely fucking brutal. Hence why the title is….

Scale Model Testing Your BattleBots in NIGHTMARE MODE

I teleported up to Norwalk over the course of the day on Friday, May 14th, and got to my (now usual…) Norwalk generic business hotel around 10pm. The event started at 9 the next morning, and it was a full house.

I started 30Haul out in the “sportsman mode” configuration anticipating needing to change out to anti-vert forks. I got “Hyperbite XL” as a first draw. It’s an homage to Deathroll from BattleBots, and luckily was very high off the ground, so I actually decided to roll with these. I was out to test a “Just reach out and grab it” strategy.

Hear me out here – pretty much every vertical weapon worth its mettle takes a few seconds to get up to dangerous speed. I’m content with declaring the clamp disposable and just going up to it and grabbing it. If they try to turn away to prevent this, so much the better.

Well I mean it kinda worked. The only downside of declaring the clamp arm disposable, is you better have a whole lot of them, which I… didn’t. So this was the outcome of “Just grab Hyperbite XL as it’s trying to spin up” – while I was able to keep it at bay, the buckling actually jammed the clamp motor so I couldn’t grab and lift so much as just toss around.

There’s no “stream clip” like some of the other matches, but the match is at 3:12:36 in the main stream recording.

Hyperbite XL managed to machine some of the tips off the forks and snap some of the threaded rods, all from the small amount of contact we made in the match. That’s the downside of fighting a modern vertical spinner – there’s so much power density that the damage slope is very steep. You can really just mess up once.

Nonetheless we were both thrilled enough with the outcome that we decided to call it “Overhaul vs. Death Roll”. See? Battlebots should just be 30lbers.

Great, one match in and I’m already on my spare clamp. I managed to hammer the other side of the first clamp (the half that didn’t become wall art) straight, just in case I had to use it again.

Of course, the next match was against Other Disko, which is a more traditional 4WD vert architecture and multiple-time champion of northeastern events. Great. Luckily, this meant i got to bust out some experimental “Vert Blockers”, extended forks that act as a ground-level push-me stick. There was a lot of fork and counter-fork action at BattleBots this past year, so I decided why not give it a try as well.

This one was fairly brutal and took a long time to recover from. The key takeaway is that Vert-away forks work until they don’t. I mean, the opening gambit was about the best I could hope for, and then it just became pear-shaped.

I think that’s my main beef against the KE meta, really. That because of brushless and lithium batteries, there’s no more compromises that need to be really made on that front. You can have a fast and maneuverable drive, a solid chassis, and an extremely effective weapon, so there’s little point in having anything else.

At one point 30haul must have gotten booped hard enough on the snoot to buckle the leadscrew that drives the clamp. Luckily I decided to actually cut one of these as a spare, or else I might have had to resort to being a lifter only!


(Maybe that would have been better….)

I next faced Marathon, which was an “Overhaul vs. Minotaur” moment, and I was rather pleased by the outcome except that Marathon was counted out under what we think were incorrect conditions. I was still manipulating it when they pulled up the countdown. I was extremely peeved to find that for some reason, perhaps due to accumulated damage and misalignment, that I couldn’t manage a lift after the grab – something was stalling out the lift motor.

(I would find out after the event when I tore the bot down that one of the matches before, likely Other Disko, had bent the lift shaft into a shallow U shape that was binding up if it had much load on it)

By this point, I’d basically run out of fork parts and standoffs, so I was just going into the last match against Stop Hitting Yourself in “With your shield, or upon it” mode. I think it was a little more “upon it” as the dual vertical disks slowly plucked the remaining wheels I had cobbled and assembled out of whatever still was kind of whole.

I mean, in the grand scheme of things, the extremely prototype-y nature of 30haul has been its downfall all along. I was more out to get the shape correct and get a feel for how it’ll drive instead of focusing on functionality, and it still ended up using a few legacy parts from 30hauls and Uberclockers past.

The most important thing was I got a lot (a whole lot, let me emphasize) of recon on how to handle the vertical spinner EDM party that is BattleBots. A lot of the design issues I didn’t like about this 30haul had already been changed on Overhaul well before now, so I got to leave Norwalk this time with some “hmm” lessons for Overhaul, such as….

  • Just grabbing the vert is a valid approach, as long as I can line it up or force them to turn away.
  • The clamp head and forks are considered disposable and will be both treated and duplicated as such.
  • Vert-away sticks work until they don’t, and I’m not sure I’m a judicious enough driver to use them effectively.

I never actually got to test the new “snout” spinner wedge, first because there weren’t any horiontal bar or shell weapons, and second because I just never finished welding it after seeing there weren’t any! To be fair, Stop Hitting Yourself had a horizontal component, which would have been trouble if they decided to use it against me.

Hey, at least a clean picture of 30Haul is on the NHRL hall of fame wall! I think this photo was actually taken during the February one I went to.

With this NHRL, this 30haul’s story comes to a close. Like I said, it well outlived its original purpose and I was just running against opponents with a whole slew of design handicaps. There will be another one in the future, probably not this year, as Overhaul itself is now my focus of attention. And of course the new one will have conversely back-propagated design elements from Overhaul 3!

The Summer of Ven: Reassembling the IDI Electric Fuel Pump System

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Last time I ripped most of the OEM fuel system out of the engine cave on Spool Bus, and received the parts needed to fabricate the new fuel system. So here’s where I get to put it all back together!

First things first, the new Facet e-pump itself has to be mounted. I chose to put it on the frame, right next to the filter head that some previous owner added. If you wanted something comprehensive, it seems like the R&D frame-mounted filter and pump kit is the go-to. But I already had the hard part done for me, so might as well use it!

And here it is all mounted up. At this point the fittings were just threaded in for visual effect – after I installed everything I realized some of them had to change.

So here’s what’s going on now with the plumbing. The long arc at the top is the inlet coming from the fuel tank selector valve. The fuel gathers at the clear strainer (so I can see how much poo is in it) and is sent to the filter head, then from there, to the rest of the fuel system.

This is what it looks like on the inside. It passes through the frame at two pre-existing holes – I suspect the filter head location was chosen by a P/O for this convenience. For completion’s sake it needs a plastic grommet here at the holes, which I ordered but wasn’t here yet (BURNOUTS NOW, GOOD IDEAS LATER)

With the system plumbed up to the filter outlet, time to test everything and give it its first powered break-in!

The magic van juice flows. The Facet pump makes a pretty loud clicking sound as it’s operating, possibly indicative of it being a vane type pump instead of a small centrifugal or axial flow turbine like most in-tank pumps that make a more whirring or buzzing sound.

I had this setup hilariously looping back on itself (hose back into the fuel tank) for about 5 minutes or so to break the pump in.

The remaining plumbing steps were all engine-side. I needed to cut the existing injection pump feeder line that went to the OEM filter housing and turn it into a fitting I could attach to the fuel hose, then add a return system.

Getting to the injection pump inlet fitting was, how should we say, unpleasant. Again, no overhead view, so this was done with a phone camera inspection video and then by feel. First, I had to remove the intake plenum thing to get access to the injection pump’s backside, which was an easy enough operation (though I had to loose and shift, but not remove, the turbo). There’s only space to turn the wrench 1 hexagon side at a time.

And here it is, the original filter to injection pump line.

I used a tube flaring tool from Harbor Freight to cut, then form, then put a gentle flare onto the end of the rigid line. It’s supposed to stick up just a little out of the center valley so I can slide the rubber fuel hose over it.

If taking the fitting off was a lengthy video game side quest, then re-mounting it was some kind of next level miniboss that didn’t even drop goodies. I had to do most of the initial mating and threading by hand.

The updated feeder line terminates in this photo just under the rubber vacuum hose to the right.

Here’s a new front-towards-back view of the now much more spacious engine cave.

The original fuel feeder line coming from the selector valve was wrapped around under the front of the engine, rising upwards on its forward passenger side face. I gently bent the rigid line where it began on the frame to point towards the back of the engine. Again, slightly badly lit photo, but you can see the “Nipple to Nowhere” pointing downwards in the center, which is where I’ll attach the new fuel line.

While doing this, even more parts had been arriving. A new expandable intake hose, for one, but more importantly, I received the electric solenoid valve and fittings for making a device I nicknamed the Dongle of Diesel Distribution:

So here’s what’s going on. The DDD takes in fuel from the pump/filter on the bottom left fitting. The electric solenoid is connected vertically above it, in order to give a high point for air to collect. It then does a U-turn while touching a pressure sensor, and the injector pump hooks in on the rightmost fitting. The top “exhaust” fitting will be routed into the fuel return lines.

I decided it’ll mount right here, at the studs where the former OEM filter housing was located.

I decided to get silly and design up a snail-shaped mount to be 3D printed. Bent piece of sheet metal? Sure, why not. But that wasn’t extra.

Whatever, it’s a snail if you squint hard enough.

It’ll be made on one of my Markforged machines from their carbon fiber nylon composite material, Onyx. My favorite vegetable for making dishes as diverse as entire beetleweights to welding fixtures to …. stuff like this.

I actually modeled this up and had it running on the printer while I was doing the plumbing work that night, so it was ready by the morning!

The finished snail bracket assembly! The only place to “mount” this so to speak was using the solenoid valve’s mounting holes.

I grab one of the studs of the former OEM filter mount to locate this thing, and also function as a ground point for the solenoid valve.

Am I confident that the print will survive underhood temperatures? Absolutely. Hell, just about everything in a new car is made of fiber-filled Nylon of some sort… to my chagrin.

Time to do some final plumbing. I’ve linked up the injection pump (hose labeled -> IP ->) and the feeder line, and the free hanging one will be the return vent line.

For fuel pump power, I fished up a long 16 gauge wire following existing brake lines to meet the repurposed fuel heater power drop.

Here’s what’s going on underneath. The orange and black bundle going off to the right is the fuel pump power.

The DDD purge solenoid is grounded on the OEM filter mount stud and I ran a purple wire up and over the engine cave (note the orange and purple wires in the wiring tray at the top) to meet the solenoid wire.

I connected the solenoid wire to a 12V access point at the Centurion-supplied fuse block. Then I pulled the doubled-up wire into the cabin via the same terrible, un-insulated, un-grommeted hole everyone else has been using (“Not the better redneck, just the most recent”) and the cut the doubled up loop. Now I just need to connect the ends to a switch to enable the solenoid.

A photo of the Wiring Teratoma now with my own additions (blue overdrive connection, purple purge solenoid….)

I found a button switch in one of my Collections and decided to just position it above the fuel selector switch. It’s a momentary button, so if I ever do some kind of service on the fuel system that empties it out, I’d just key ON (not start) and hold the button a few seconds to let the system quickly prime.

To be fair, once you have an e-pump, it will eventually shove all the air out of the system anyway, save for any air that might be trapped in the injection lines themselves which will need to be individually bled at the injector (no thanks) or cycled out through brute force.

On the reassembly path some more! Here’s the back side of the intake reassembled with the new extend-o-hose, now free to run diagonally across the engine cave without tripping on ANYTHING.

The “Cold” “Air” “Intake” is now back in place as well. That’s really all there is to it for this install.

And now we’re ready to fire back up. Verdict? Well, it works the way it’s supposed to. If I push the purge button, fuel begins blasting out of the return tee junction instead (oops, forgot to tighten that clamp). However, now that the system is being consistently pressurized to 10 PSI, I’m watching ALL of the injector return fittings spew diesel fuel every time the pump is running.

Welp. That’s what the next post in this series will cover: all the collateral damage, including repair of the return lines and fittings. While I waited on these parts, I also decided to get new glow plugs and repair that circuit.