# P3.5 measurement plan — no observations recorded

The first rig is a low-pressure component test. The vehicle and cold-recovery
branches remain separate until measured force, electrical and heat balances close.

## Four-port air-routing rig

Use the supplied metre-scale STEP geometry as a layout reference for a rated,
restrained low-pressure housing. Complete shafts, seats, seals, fixtures and
actuators before fabrication; the modelled 0.12 mm gate gap is not an airtight
seal. The housing length is 240 mm, inlet bore 84.4 mm, four outlet bores 27.64 mm.
Instrument a shared inlet and rotor, with independently measured bank loads.

Record calibrated horizontal force, vertical force and torsional moment, upstream
and downstream total/static pressure, inlet temperature, mass flow, rotor speed,
valve angle, leakage and full DC voltage/current. Include motor and control inputs,
startup energy and actuator work. Tare the fixture at zero flow. Repeat open,
single-port-closed and paired-isolation poses at fixed input settings. Reverse the
left/right fault and repeat to test symmetry. Record uncertainty and raw time data.
Do not infer a full-car installed force from a small isolated duct.

## Cold-pressure rig

Use a rigid 10 litre vessel rated for the complete pressure range, a 20 to 0 C
water jacket, calibrated absolute and ambient pressure sensors, a gas-temperature
probe and an isolating inlet valve. Account for vessel, jacket, hose and leak heat
loads. Keep water out of the air path. Stabilise initially at 20 C and 101.325 kPa,
isolate, cool slowly and record temperature and pressure at equilibrium.

The ideal dry-gas target at 0 C is 94.412 kPa absolute, a 6.913 kPa deficit.
At a maintained 0 C, opening to ambient admits about 0.882 g extra air before
pressure equalises. Measure finite mass and the complete heat input/removal.
The 172.8 J gas cooling result excludes vessel and equipment heat capacity.
The 2.573 J fill work is an ideal upper bound, not a turbine selection or output
prediction. A throttled valve will dissipate the available pressure work.

## Evidence record

Log instrument calibration, initial conditions, geometry, material and actuator
specifications; repeat measurements before fitting parameters. Reserve separate
runs for validation. Keep failed and successful traces. Revise the model from
measured force, leakage, heat and power maps, then repeat the coupled scenarios.
No high-speed vehicle trial is specified or authorised by this bench protocol.
The separate nitrogen thermodynamic calculation is not a cryogenic rig design.