Crimson Racing Wiki

Pneumatic Shifting Tubing

Subteam: PowertrainSubsystem: ShiftingAssembly: Shifting System AssemblyCars: CR21

Purpose

CR21 naming for the pneumatic lines.

Function

Braided line with crimped AN fittings. Crimped fittings remove the hose clamp as a failure point and let the line hold higher pressure than rubber hose. All lines are modelled in SolidWorks before they are made.

Design Process

No part-specific design process is documented. The Shifting subsystem design process applies: 1. Route every line and fitting in SolidWorks. Lines cannot be within 1 in of the engine casing or 3 in of the exhaust; bend radius is 4 in. 2. Size the cylinder bore and line inner diameter with full calculations rather than by picking a catalogue part. 3. Fit the linear potentiometer and set the position bounds that define a completed shift. 4. Tune the preload duration and the torque reduction window on track. 5. Measure the result. CR26I averaged 65 ms cut time across endurance closed loop against 85 ms open loop; across 180 upshifts that is 9 seconds under power cut instead of 15.3 seconds.

Manufacturing Process

Cut to the modelled length and crimped.

Full Material List

Nylon pneumatic tubing.

Reoccuring issues

None recorded. This part has no entry in Knowledge_Transfer/Issue Logging/Fault Vault.xlsx, in either Issue Log.xlsx, in CR22/Issue Tracking/Shakedown 7-15-23.xlsx, or in any design review issue list found in CrimsonStorage or Box.

Still to document

Nothing in CrimsonStorage covers these yet.