Kyosho Ultima UM-301 main chassis (stock and 2mm shorter wheelbase versions)

thingiverse

This is a custom main chassis plate specifically designed for the vintage Ultima ST EP Type-R. I crafted it to maintain the original look of the stock chassis while shortening it by 2mm to address its poor turning ability caused by the stock chassis. This modification also takes into account that the stock part has been discontinued for some time, making this a unique opportunity to upgrade your old Ultima. The chassis is shortened from the battery area, leaving other parts untouched and ensuring compatibility with all stock components except the stock battery holder. If needed, I can produce custom length versions of this part. Newer Kyosho RB models, including the RB5, appear to use a similar-looking chassis, but their exact length and fitment are unknown. To ensure 100% compatibility, I designed these parts from scratch, making them specifically tailored for my application. To achieve optimal results, it's recommended to print this part using CF-infused filament like I did, but other filaments can be used as well. I've also included the UM-304 battery holder, which is 2mm shorter than the stock version. Feel free to comment or post a make on how this works for you, and let me know if you'd like any changes made. Be sure to check out my other parts designed specifically for the Ultima ST Racing Sports/Type-R/Evolution chassis. Here are links to my project: https://www.rcuniverse.com/forum/rc-nitro-stadium-trucks-243/11675757-my-ultima-st-gp-type-r-evo-20th-anniversary-project-3d-printed-cf-parts.html https://www.rc10talk.com/viewtopic.php?f=30&t=44634 UPDATE! I've added the stock chassis version for those who prefer the same wheelbase as the original ST had. I've also included the stock battery holder in case it's needed. The version number has been updated from 1 to 2, with minor fixes and reinforcements to front upper frame posts and rear chassis posts. UPDATE! 30.1.2021. I've uploaded v3 of the chassis, which is a stock length design but includes several modifications for improved durability. V3 Modifications: - Front chassis posts have been upgraded to use 25mm length and 5mm OD M3 threaded aluminum post standoff spacers. Simply press-fit them in place and secure with screws from underneath the chassis. - Rear chassis Ultima ST/RB stock posts have also been upgraded, using the same 25mm standoff spacers mentioned previously. - Body posts have been added to support RB5 rear sections (UM508C). - The original Ultima ST's and RB's are still supported, with no issues. - The rear lower part of the chassis has been modified to accommodate RB5 rear chassis plates and hinge pin mounts. This allows you to mix and match parts from different models. - A small slit has been added for routing the steering servo cable neatly. - Another small slit has been included for easier antenna wire routing (mainly for those using AM/FM radios). - As always, I've printed and assembled these parts myself. I used Carbon Fiber-infused PETG to print this chassis, which fits perfectly on a Prusa i3 MK3s print bed. The print settings were 0.20mm layer height, 100% infill, and supports only on the print bed. Printing took approximately 9.5 hours. UPDATE! I've just tested the V3 chassis with the whole Ultima RT5 frontend and backend, and it's fully compatible.