Sets the vertical offset of the CR22 rear inboard undertray mount, which is what sets undertray rake.
Because the undertray is mounted independently of the chassis, offsetting the rear inboard mount changes the tray's rake without changing the car's suspension setup. CR26I replaced fixed spacers with adjustable dog bones in the mount.
No part-specific design process is documented. The Undertray/Floor subsystem design process applies: 1. Sweep tunnel geometry parametrically in CFD: expansion ratio, choke height, inlet shape, outlet length. Findings were peak efficiency at expansion ratio 5.14, peak downforce at 5.44, flat inlets greatly reducing drag, greater choke heights helping, and outlet length having little effect. Stall is the limit. 2. Add the center tunnel where packaging allows. CR26I outboard tunnel width fell from 11.63 in to 6.94 in because of the wider EV frame, so the center tunnel recovered the lost area. Center section efficiency 25.2, outboard 12.6 on Iter17. 3. Check the design against the aero no-go surface derived from worst-case heave and roll with Suspension. 4. Package around the exhaust, oil pan, jack bar, radiators and sidepods, with inlets and outlets positioned away from direct tire effects. 5. Validate on track with Flo-Vis on the bottom surface and constant-speed CL measurement.
Turned on the CNC lathe, or milled where the geometry is not round.
Aluminium.
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.
Nothing in CrimsonStorage covers these yet.