Mechanical design, starting from mission failure

In a confined network the first mechanical problem is recovery. Looks come second. Sharp edges snag cables and sediment. A cage that cannot be swapped writes off the whole vehicle after one hit. If ribs block the view, the best algorithm can only label “cannot see”. Design inputs therefore start from failure modes: jam, unknown attitude after a roll, one-person well-head carry, disinfectant compatibility, battery impact.

External products set candidate ranges. S300 spherical protection and modular sensing, THS-04 ducted omnidirectional protection, Elios-class collision tolerance, Scout 137 tethered recovery — all are study objects. Their public numbers are not PipeGuardian measured specs. A P1 target freezes only after scene measurement, mass/power budget and repeated tests.

P0 proves space: rotor clearance, a coarse CG, well-head passage, a human grab. Wood, 3D print and ballast are allowed. A P0 photo may explain semantics. It must not sit next to “collision verification complete”. P1 introduces a replaceable cage, a real battery path, sensing windows and repeatable collision. P1’s job is a failure list, not a film. P2 talks split lines, tolerances, gauges and a second source. Without P1 raw logs, P2 only makes an unverified structure look more like a product.

Shenzhen engineering shows its value in that split. P0 can finish in any lab. P1 tool changes, finish and connector life need suppliers who can visit. P2 BOM freeze needs inspection records, not a spoken lead time. Hong Kong keeps the test plan and evidence writing so engineering speed does not run away with the right to claim. If both sides try to book the same prototype invoice into different subsidy files, the configuration library will fight the filing ledger.

Materials upgrade by gate as well. Round one compares glass-filled nylon, elastomer over-mould, aluminium skeleton and local carbon fibre on impact, repair, decontamination and flame retardance — not a density contest. Sacrificial parts must be identifiable, stocked and replaceable inside a ten-minute target. Fastener orientation is poke-yoke so a left part cannot go on the right at the well-head. Cable strain relief and connector locks must confirm with one hand. Until CDR those sentences are design requirements, not test conclusions that already happened.

Aero and heat cannot rest on outdoor hover data. Near-wall pipe flow changes thrust and recirculation. Full lighting plus compute plus a gas pump is a different thermal load from empty hover. Endurance targets therefore count under a defined “standard-payload mission”. The spec page may keep writing “target” until that statistic exists; it may not delete the word. The mechanical centre can veto any request to put empty-hover numbers into public materials.

Minimum rig list: multi-direction drop or pendulum; replaceable pipe sections (straight, elbow, reducer); controllable illuminance and mist; cal-gas ports; a recovery rail or well-head mock; synchronised cameras and IMU. Each test writes hypothesis, primary metric and fail criterion in advance. A test that cannot count repetitions cannot upgrade S3.

Rigs also serve the course. If a graduate piece cannot be reproduced on the same fixture, the documentation failed. Visitors may see the rig. A visit is not certification. Certification belongs to G6 laboratories and the site owner.

Relation to the eight design steps: interference, heat and service problems found on the rig must flow back into CAD. A render must not hide interference. Change records write root cause, affected parts, verification and a signature, or the configuration library collapses in week two. The centre exists so that loop is daily work, not a post-accident patch.

Every replaceable module needs a drawing number, material lot, mass, interface version, test status and a forbidden-pairing table. Field kits carry released combinations only. Software version and mechanical version must record each other, because flight-control filtering may depend on a specific inertia. Scrap is marked and isolated so “it still flies” does not become oral tradition.

A second source is investigation only before P2, not a promise. Dual-sourcing too early copies unfrozen tolerances twice. Inspection templates are written now: dimension, torque, insulation, cell origin. Those files later serve G6 and the no-double-funding cost ledger.

Industrial-design orange marks hazards, grab points and service contacts only. Final brand VI remains unfrozen. Dark grey / black is a working colour, not a registered trademark expression. The mechanical centre refuses drawings that treat the concept-model image as a production render.