Crimson Racing Wiki

Paddle Shifter

Subteam: ChassisSubsystem: SteeringAssembly: Paddle Shifter AssemblyCars: CR25, CR26I, CR26E

Purpose

Lets the driver request an up or down shift without taking a hand off the wheel.

Function

A lever behind the steering wheel operating a switch that sends the shift request to the MoTeC M150, which then runs the closed-loop pneumatic shift sequence.

Design Process

No part-specific design process is documented. The Steering subsystem design process applies: 1. Kinematics sets steering geometry, Ackermann targets and rack travel. 2. Size the column and shafts for torsional stiffness and for the bearing housing that supports them. 3. Calculate static steering force from the tire and geometry, and check it against anthropometric limits. 4. Design the wheel shell around the button and switch layout and the dash sightline; prototype grips and take driver feedback. 5. Validate steering effort and Ackermann on track, using the alternate tie rod mounts to sweep setups.

Manufacturing Process

3D printed in PETG. Rapid prototyping and driver feedback drove the final shape.

Full Material List

PETG, 3D printed.

Reoccuring issues

CR22 Issue Log, 2024-02-10, Chassis. A shifter paddle failed and fell apart in the driver's hands, from a lack of material strength combined with the force needed to press the paddle. It was replaced with a spare from the shop. The recorded permanent fix is to investigate stronger materials and new geometry, which is what led to the CR26I PETG prototyping and driver-feedback iteration.

Improvements

Redesigned in PETG with rapid prototyping and driver feedback, after the previous paddle fell apart in a driver's hands and after earlier designs had interference issues.

Still to document

Nothing in CrimsonStorage covers these yet.