Support the individual driver's body so they can hold position and modulate the controls precisely through a full endurance stint.
A per-driver insert molded from 2-part marine expanding foam directly in the car, so it takes the shape of that driver against that seat. It drops into the seat, the belts route around and through it, and it velcros to the firewall, so swapping drivers takes minutes.
Molded to the driver in the car, then post-processed by hand and covered with fire resistant fabric. Support points identified from the anthropometric study: lower back, hips, upper latissimus dorsi, and lateral to posterior deltoid.
Must not interfere with belt routing or with the 5 second egress requirement. Must be fire resistant. Must be interchangeable between drivers.
Validated by EMG. Mean frequency of the muscle signal drops as the muscle fatigues, so a smaller baseline-to-post-stint frequency shift means less fatigue. Sim half-endurance results: left forearm baseline 154.05 Hz, actual setup 138.49 Hz, optimal setup 145.47 Hz; right quad baseline 111.80 Hz, actual 104.51 Hz, optimal 107.51 Hz.
Two-part marine expanding foam poured and molded around the driver in the car, hand post-processed, covered with fire resistant fabric.
Two-part marine expanding foam, fire resistant fabric cover.
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.
Lap deltas fell measurably once seat inserts were introduced; the largest delta in the 2024 data is 8.7 s, with no complaints of lack of support since.
Booster seat weighs 0.1 lb. Inserts exist for the 25th, 77th and 98th percentile male drivers in the current pool. Quantity per car, as costed: 1