0.00Stationary time, s

Pit Crew 3D

The WAD 231 pit-stop FRAM model, calibrated against 135 real FIA stops, played out by the crew. Stage 4: race situations: double-stacking, wing changes, wet tyres and pressure.

0.00 sReady

Slowest part– Stopping error– Seed–

Speed 0.25×

Corners: gun off to gun on

1,000 stops: failures against the calibrated crew

Uses the current conditions and failure rates, with the same 1,000 seeds run with and without the extra failures.

Release procedure

Crew

IdleWaitingWorkingDoneRedo

Events

Run a stop to see what happens.

Race situation

Double-stack: team-mate queued behind Car 2 arrives after car 1 stops (s) Front wing Wing work time, mean (s) Tyres and track Release rule

TD022B, in force from the 2021 Belgian GP: the go signal comes at least 0.1 s after the jacks start to drop. The July 2021 draft would also have held each jack 0.15 s after its last nut, with 0.2 s before the go signal; the FIA dropped both.

Race pressure (%)

Assumed effects, for exploration. Wet track: stopping errors × 1.6, routine variability × 1.15. Pressure: variability up to × 1.5, rushed-nut failures up to × 2, and crew rush sooner. The second car of a double-stack gets 25 points of extra pressure.

What if: one corner slower

Front left, task times (%) Front right, task times (%) Rear left, task times (%) Rear right, task times (%)

Scales the four task times at that corner: gun off, tyre off, tyre on, gun on. 100% is the calibrated crew. The crew still judge "late" against a normal stop, so a slow corner makes its gunner rush when rushing is switched on.

Conditions

Stopping error along the car (cm) Stopping error sideways (cm) Gunner stance from the wheel (cm) Routine variability (1 = calibrated crew) Rush the wheel nut when the corner is late Rushed nuts that fail (%) Sticking wheel nut, per corner (%) Traffic in the fast lane (%)

Failure modes

Wheel-gun failure, per corner (%) Cross-threaded nut, per corner (%; ×3 when rushed) Jack fails to lift, per stop (%) Wheel not seated but gun signals tight, per stop (%)

Zero reproduces the calibrated model exactly. The illustrative rates are assumptions for exploring couplings, not measured values.

Engine: WAD 231 (33 functions), timings and failure rules unchanged from the Pit Box Simulator, with the ETTO coupling that fits the FIA stops (error 0.05). The car and crew are schematic: a generic single-seater, team colours and kit invented.