# P2 premium material and manufacturing specification

This specifies an **unbuilt 1:10 bench article**, not qualified road, crash,
cryogenic or pressure-vessel hardware. The user requested new premium materials.
No supplier order, purchase or expenditure has been made.

## Material selection

| Component | Specified material | Build route and reason |
|---|---|---|
| Flow passages and inlet/outlet blocks | New 6061-T651 engineering plate with mill traceability | CNC split ducts provide inspectable internal surfaces and controlled joints. The material choice prioritizes dimensional repeatability. |
| Removable body panels | New Toray G-83CM carbon/epoxy prepreg, reinforcement confirmed by the supplier | Matched tooling and documented cure; a smooth lightweight shell with independently inspected geometry. The actual laminate is a specified composite, not the raw carbon-fiber properties. |
| Thermal spreaders and dummy heat-exchanger insert | New C10100 / Cu-OFE / CW009A copper | Separate machined inserts for a later metered thermal stage. Copper is not a source of extra energy. |
| Isolation bushes and thermal spacers | New certified unfilled PEEK stock | Isolate the copper/heater and composite/metal interfaces according to actual contact temperature, creep and joint requirements. |
| Bench seams | New traceable PTFE gasket stock or a shop-qualified sealant, selected with final joint geometry | Keep seals and bondlines outside the measured flow surfaces; qualify leakage and disassembly repeatability. |
| Force balance, mount and fasteners | New calibrated laboratory hardware, traceable stock | Select ranges for both dead load/moments and aerodynamic resolution; calibrate the entire installed setup. |

Primary material references: [Kaiser 6061-T651 engineering plate](https://online.kaiseraluminum.com/depot/PublicProductInformation/Document/1046/KaiserSelect_General_Engineering_Plate.pdf),
[Toray G-83CM system](https://www.toraycma.com/wp-content/uploads/G-83CM-PREPREG-SYSTEM.pdf),
[KME Cu-OFE](https://www.kme.com/fileadmin/DOWNLOADCENTER/COPPER%20DIVISON/4%20Industrial%20Rolled/3_Datasheets/Datasheets_NEW_2021/Cu-OFE_01_2021_e.pdf),
and [Ensinger unfilled PEEK](https://www.ensingerplastics.com/es-es/semielaborados/plastico/peek-tecapeek-natural).
These references support material identification/selection; they do not certify
this assembly, a laminate layup, a joint or a vehicle.

## What “new and fresh” means for procurement

- New unused plate, polymer stock and components, with manufacturer, grade,
  temper/condition and lot records. No unidentified stock or salvaged parts.
- Prepreg supplied within the manufacturer's shelf-life and out-time limits,
  with storage/transport records and a batch cure record. No unknown freezer stock.
- Supplier certificates and incoming inspection remain linked to each serialised
  test article. A material substitution requires a recorded engineering review.
- “New” metal stock does not mean a claim of zero recycled content: composition,
  temper, traceability and inspection establish the specified quality.

## Precision targets — requirements, not achieved results

- Flow-surface roughness: Ra at or below 0.8 micrometre after machining/finishing.
- Internal profile and assembled joint step: at or below 0.05 mm target.
- Keep paint, adhesive squeeze-out, tape edges, gasket beads and loose fibers
  out of the bore. Do not fill a flow defect without recording the geometry change.
- Initial dry-air leakage target below 1% of the measured duct flow at the actual
  test condition. The appropriate leak-test pressure follows the rig design.
- Measure actual roughness and form. Ra is not automatically an equivalent sand
  roughness height for CFD. The present cold CFD uses smooth walls for every case.

The machinist must confirm achievable tolerance and inspection access before the
STEP files become released fabrication drawings. No numerical result in this
package demonstrates those targets have been manufactured or met.

## Machined duct quote package

The two routes are derived from one master and mirrored exactly. Each is split
at the common z=40 mm plane so the internal passage is accessible from a machining
face. STEP files in `cad/` include complete duct-shell and upper/lower quote solids.
Units in the CAD/CFD generator are metres; STEP carries its unit metadata. Quote
drawings and the assembly view use millimetres. Verify the 480 mm body length on
import before machining.

Nominal duct wall is 2 mm, formed by lofting an expanded section around the fluid
passage. This is a nominal section offset, not a verified constant-normal wall
thickness everywhere on the curved bore. Minimum wall and tool reach need CAD/CAM
inspection. Joint flanges, fasteners, datum fixtures, bonds and shop allowances
are not finalized: the current solids are **quote/DFM geometry**, not a released
pressure fitting or complete manufacturing drawing set.

The geometric aluminium mass estimates in `flow-duct-halves.json` use the
nominal 2700 kg/m3 density. They exclude joints, mounts, thermal inserts, surface
treatment and manufacturing changes. Do not use a solid external CFD body volume
as the mass of a hollow composite vehicle.

Proposed quote blanks are two 500 x 110 x 45 mm upper and two 500 x 110 x 35 mm lower
pieces of new 6061-T651 plate. These are provisional stock allowances, to be checked
against exported bounds and the shop's fixture method. They are not purchase orders.

## Composite shell

Use a supplier-confirmed prepreg combination and mold process. A symmetric balanced
woven-panel concept is an initial layup candidate; final ply count, cured thickness,
cutouts, inserts, cure and post-cure follow the selected material system and actual
loads. Do not assign raw-fiber strength/modulus to the finished laminate.

Inspect profile, panel steps, voids and inserts. Isolate carbon/metal contacts with
the designed barrier/bush/joint system and verify it after cure and thermal cycling.
The complete shell laminate, inserts and mount require coupon/part validation.
Neither the carbon material nor its cost provides an assumed aerodynamic credit.

## Thermal stage and test equipment

Retain the initial 12 V, 24 W total thermal-dummy ceiling and 45 C hardware cutoff
as starting laboratory settings, subject to actual material/joint verification.
Independent airflow/temperature protection and electrical isolation precede heating.
Measure electrical input, heat delivered to air and parasitic losses separately.
The current CFD cases are cold; copper and prepreg properties do not alter those
results through an unmodeled thermal effect.

Procure a calibrated laboratory balance with enough static load and moment margin
for the final article. Aerodynamic standard uncertainty target is <=0.002 N per
needed force axis after the mount, tubing and wiring are installed. This target
requires verification and is not a claim that a selected product already meets it.
Use a common timebase for forces, pressure, flow, temperature and power.

## First physical build sequence

1. Shop DFM and datum/joint review of the split duct STEP files.
2. Order only against an agreed budget and accepted drawings; retain stock records.
3. Inspect dry parts and assemble the cold-flow article; measure seams and leakage.
4. Calibrate the mounted balance and pressure/flow channels with the actual wiring.
5. Repeat matched P1/P2 cold tests, then outlet settings, then the thermal insert.
6. Keep actual masses, roughness and measurements separate from CFD predictions.

Gas stores, freezing-water work, cryogenic routing, contact pads, road control and
ECRS retain their separate qualification stages from the full plan. This material
specification does not qualify their vessels, magnets, rotors, brakes or controllers.