Ice race wheel for RC touring car

thingiverse

Update 16-01-2020: Time for the new design. It takes into account the lessons learned last year, or so it seems. We won’t know until race day. It uses 0,8x12 steel nails. I print the wheel at 104% in X and Y, and 92% in Z. After printing I cut the heads of the nails and press them in using a piece of plastic cutting board (not to damage the tip). Then I bake them again which will hopefully anchor the nails in the wheels. It’s quite a tedious task, 192 nails (24 per wheel, two sets of four wheels) and I punctured my hand several times while doing it, so be careful. Again, no guarantees. It feels like a better design, but the 0,8 mm nail does not seem very strong… I will bring last year’s wheels to the track, too, in case these fail. The old ones aren’t perfect, but have proven to last. Unless the PLA deteriorated over the year, which it probably did. Oh boy, why am I doing all this in the first place… ;) Update 28-01-2019: Well, that did not go according to plan… Yesterday I raced the wheels on my TT-02 chassis on the ice, in an ice hockey arena. When the track got scratched (and that happens quickly as everybody takes the racing line), it all went downhill, quick. There are two issues: - The spikes are spaced too far apart on the width of the wheel. Now 10 mm, 5 would be better. Bigger chance of both rows finding grip. - The screws I used have a very sharp point, but they become wide fairly quickly. Looking at them from the side the whole screw tip has an angle of about 45 degrees to go from pointy tip to 2 mm thread diameter. This means when the track is new, you race on the pointy tips and that works. When the track gets damaged, the part toughing the ice will almost always be the side of the 45 degree tip, which does not provide nearly as much grip. The winner drove with 0,8 mm steel nails with very long tips, on narrow wheels. So for next year’s race, its back to the drawing board. Is was a lot of fun, though, and for fun use (or a class with this design mandatory) they are very usable. Many wheels were killed on the track yesterday, mine held up very well. Original project: IJsrace wiel (English below) Voor het jaarlijkse ijsracen bij de ERCE heb ik deze wielen ontworpen. Er gaan per wiel 24 schroefjes in van 2x12mm met verzonken kop. Let op dat je wel staal of RVS koopt, niet messing. Dat is veel te zacht. Ik print ze in PLA op X en Y 105%, Z op 96%. Dan gaan ze 75 minuten in een niet voorverwarmde over op 110 graden Celsius. Dan krimpen X en Y naar (ongeveer) 100% en Z groeit naar (ongeveer) 100% en het wordt veel sterker / taaier. Of dat voor jouw PLA ook zo is moet je proefondervindelijk vaststellen. Ik heb de wielen op een bevroren slootje getest, het gaat best goed. Geen garanties voor de race… Ik weet dat ze op de Tamiya TT-01 en TT-02 chassis passen en ze zouden op ongeveer ieder touring car chassis moeten passen. Niet vergeten je chassis waterproof te maken, er komt veel spray van de wielen in de auto. De supports zijn lastig te verwijderen, zeker bij dit ontwerp. Sorry! Nadat ik zoveel mogelijk van de binnenkant verwijderd heb, duw ik een dunne inbussleutel van bouten naar binnen door de schroefgaten om alles schoon te krijgen. (De foto is van een prototype dat te klein kromp / niet groot genoeg geprint was en waar de schroeven 3mm uit staken. De definitieve versie steken ze 4 mm uit. Dat is de bijgevoegde STL file.) Ice race wheel Designed for our club’s annual ice racing event. It takes 24 screws, 2x12 mm each with countersunk head. Please buy steel or stainless steel screws, brass ones are too week. I print them in PLA at 105% for the X and Y dimensions, and 96% for Z. Then they go in a not-pre-heated oven for 75 minutes at 110 degrees Celsius. This shrinks / expands the wheel to (around ) 100% and becomes a lot stronger / more tuff. On the frozen little canal I tested a little, they seem to work. No guarantees for racing… I know they fit the Tamiya TT-01 and TT-02 chassis and should fit pretty much any touring car chassis. Don’t forget to waterproof your chassis, a lot of spray from the wheels ends up inside the car. The printed support is a hassle to remove, especially on this design. Sorry! After cleaning it off as much as I can, I clean out the screw holes by pushing a small Allen key from the outside inwards (The picture is of a prototype which shrunk too much / was printed too small, and had the screws stick out 3 mm. The final version has them stick out 4mm. This is the STL file attached.) Nozzle: 0,4 Layer height: 0,3 to start, 0,2 for the rest Infill: 20% Top and bottom: 4 layers Walls: 3 layers Supports: yes, to build plate only Brim / Skirt / Raft: Brim