WOOOOOOO I made it in! Thanks to the multiple people who sent me reminders. For the record, I spaced out last year on the first round completely, but this year I was paying attention and still wasn't fast enough on the first round. It got a bit shaky there when the BDB went down but we made it.
I may drop the sportsman later if it looks like I won't get to it, but for now it is registered. If you know somebody who is trying to get into that class, then consider this inside information for all three of the people who watch the sparc forums
For Hyperpolarized I'm planning upgrades to these things:
1. Better idler setup. The old one was a nightmare to maintain, it wore down in almost every fight and depended on a complicated disassembly process to repair. I tried to make it as small as I could and expected to never have to mess with it but this shell is just a tiny bit uneven on the top so it gets obliterated at the speeds I'm spinning. Clearances on the top for this bot are so much tighter than the last few that the idler is way more involved. I'm hoping a better idler will allow it to hold a heading better. It's hard for you guys to see, but this robot slews to the side really bad while driving. I made it super flat so it would be super stable, but the goal was to make it way more mobile than the last version. In the end it is much faster and more stable, but with the oversteering problem it wasn't actually any better at going where I want when I want. That's going to be vital with all of these terrifying bots.
2. Better lexan mounts for the top. The old pie wedge shaped plastic pieces don't have enough overlap with the steel shell. That means the screws are mounted too close to the edge of the plastic, and the slightest impact causes the plastic to crack around the screw holes and break apart. This makes the shrapnel guard into shrapnel, and allows the screw to come loose. That's bad because it then drops between the shell and the mid plate and gets caught on the weight/cooling holes in the mid plate. That binds the shell up. Not a huge thing at full speed other than having metal bits in the innards, but if it is stopped it can jam the shell up and screw up the roller. I'm pretty sure this is what cost me the two fights at the end of moto last year. I actually have a pic of the scrape mark where the screw gouged the mid plate and then hit one of the holes. I don't know when it happened exactly, but I can see that being a problem. I'm going to rework the midplate holes to avoid alignment with the screws and also improve the mounting for the screws. My current plan is to weld little threaded spacers to each of the shell spoke braces and do a single continuous lexan circle above the spokes, with rubber gromments for the mounting holes. That should eliminate the cracking issue other than on a pretty significant hit, and mean the screws can't fall into the bot as easily.
3. A better center post setup. The current post was a last-minute retrofit of the Threecoil flywheel as a bearing surface. It is soft and only mostly round. It worked remarkably well for being so last minute, but I want to redo it out of a real machined part. Basically the bearing inner race I got was a very loose fit on the bearing and it led to way too much wobble. This is probably .002-.005 bigger and it was way better, but I don't trust it. Basically I'm thinking I'll make a single steel bowl shape and get rid of the center aluminum plug. That should save a lot of weight and allow a custom fit surface for the bearing.
4. Better skids around the edge of the shell besides the idler. These are wearing down reasonably fast as expected, but I didn't do a good job planning how much maintenance would be required and how hard it would be. Right now I basically have to pull the electronics box apart to get to a nut on the other side of the screws AND remove one of the standoffs that blocks the wrench. It's a huge hassle, and a threaded mount would have fixed it. Basically I'm thinking I'll rework the corner blocks on the electronics boxes into a combined standoff and frame mount that I can also use to mount a skid. It'll be annoying to make four of them, but compared to the effort last time it shouldn't be too bad.
5. A better power switch / LED setup. The current setup works fine for drive, but requires me to hold the charging switch while I turn on the weapon to prevent the giant arc from the weapon controller caps filling. This spark is what cost Thomas Kenney on Shaka - eventually it burned through the plastic of the whyachi switch and grounded on the mounting screw to the frame (from some other wiring damage that caused the frame to ground). It led to a bunch of bad electrical gremlins and eventually a meltdown. The charging switch is good, but a bit of a hassle, and the voltage is too much for the LEDs and resistors I had on hand, so I'm going to do a more legit job with that this time. At moto I depended on the weapon controller sound to know the weapon was on (plus the drive controller LED) and that is nerve racking at the show. I just ran out of time to finish it.
To make all this happen I still have about a half pound in the budget, and I can save another half with the center post redo I bet (haven't run the numbers yet). Unfortunately a legit idler is going to take up enough space that I don't think my power switch setup will work. I have a new design I want to try that is loosely based on a fingertech switch but includes a charging circuit and some compliance to allow for an extra tight hold even in a high vibration environment. I've been happy with the whyachi switches, but they are so expensive now and so big that I'm looking elsewhere. The little black four-position style with the copper screw just sounds too unreliable to me so I'm toying with my own solution.
Looking forward to the build and to moto. It's going to be vicious and a lot of fun. I'll try to post here as I have progress but it is likely to be sporadic through the end of the year. We shall see!
-Zac
