Andean Duct Flutes Build Packet Print Packet

Generated: 2026-05-09

Packet folder: `/tmp/andean-duct-flutes-codex-bob-r3-build-packet`

File Map

design.md

Project intent, catalog metadata, assumptions, and validation plan.

Design

Design Intent

Create an L2 root-mode build packet for a small family of Andean duct flutes

that can be prototyped with PVC before committing to hardwood or bamboo. The

first prototype is a G4 pinkullo-style fipple flute with a removable block so

the windway, window, and labium can be tuned independently from the tube.

This packet supports issue #1 by providing a reviewable shop candidate. It does

not claim L3/build-ready status until the first prototype speaks cleanly and

the tuning rows in `validation.csv` are filled with measured data.

Governing Model

The starting acoustic model is an open-open pipe:

f = c / (2 * L_eff)
L_eff = L_physical + 2 * 0.6 * radius
c = 13552 in/s at 68 F

Tone-hole first pass:

distance_from_foot = acoustic_length * (fundamental_hz / hole_hz)

The formula sizes the bore and first-pass holes only. The duct-flute voicing is

empirical: windway height, window length, block fit, labium edge quality, and

breath pressure determine whether the pipe speaks.

Prototype Family

Physical lengths include first-pass end correction and 0.25 in trimming

allowance. They are deliberately long until measured tuning confirms the

block/window behavior.

Duct And Window Starter Geometry

Scale Options

Pentatonic minor offsets are the first tuning target: `0, +3, +5, +7, +10,

+12`. A hexatonic/diatonic test can be drilled on a sacrificial PVC body after

the pentatonic body validates the duct geometry. Do not mix scale experiments

with the first voicing validation body.

Materials

• PVC proof-of-tune: 1/2 in nominal pipe or tube stock with measured actual ID.
• Hardwood follow-up: straight-grain cherry, maple, or walnut blank.
• Bamboo follow-up: only after node spacing and wall thickness are measured.
• Block: cedar, maple, or Delrin insert, fitted airtight but removable.

SolidWorks/OpenSCAD Handoff

This packet does not include production CAD. The first geometry handoff should

be a simple axisymmetric bore plus rectangular window/block model with named

inputs for bore ID, OD, body length, window length, windway height, and hole

stations. CAD should not be treated as final until the G4 PVC body validates

the windway/window relationship.

L2 To L3 Gates

• G4 prototype speaks at low and medium breath pressure.
• Fundamental and five tone holes are within +/-15 cents before final tuning.
• Final trim brings the scale within +/-8 cents or records why that target is

not practical.

• Block can be removed and reinstalled without changing pitch by more than

5 cents.

• A hardwood or bamboo body copies only measured PVC geometry, not estimates.

bom.csv

Starter bill of materials with part categories, quantities, drawing refs, and notes.

sourcing.csv

Supplier/search tracker with specs, price/date fields, lead time, substitutes, and risks.

cut-list.csv

Rough/final stock sizes, material, grain/orientation, operations, yield, and offcuts.

drawing-brief.md

Manufacturing drawing and technical product sketch brief.

Drawing Brief

Required Sheets

1. Overall G4 body elevation with head datum, foot datum, window setback, and

all tone-hole stations.

2. Bore and block section showing removable fipple block, windway height, and

leak-control surfaces.

3. Window/labium detail with windway width, window length, ramp angle, and edge

note.

4. Drill jig/story-stick layout for repeatable hole placement.

Datum Scheme

• A: bore centerline.
• B: foot end after square trim.
• C: top surface orientation through window and front holes.

All tone-hole stations are measured from datum B. Window and block dimensions

are measured from the head end and cross-checked to datum A.

Tolerance Notes

• Bore ID is measured, not assumed from nominal pipe size.
• Tone holes start undersize; final diameters are validation outputs.
• Windway height is a controlled empirical variable and should be called out as

adjustable on the drawing.

assembly-manual.md

Shop-facing sequence, tools, fixtures, safety, tuning, finishing, and maintenance notes.

Assembly Manual

Scope

This manual covers the G4 PVC proof-of-tune body. Hardwood or bamboo bodies

should copy only the measured geometry from a successful PVC prototype.

Steps

1. Measure the tube ID, OD, and straightness at three stations.

2. Cut the body 0.25 in long and square both ends.

3. Mark the head datum, window setback, and foot datum.

4. Cut a conservative rectangular window and leave the labium edge slightly

heavy for hand finishing.

5. Fit a removable block so the windway is centered and airtight.

6. Shim or sand the windway toward the 0.040 in starter height.

7. Form the labium ramp to about 35 degrees and sharpen the edge.

8. Play first sound before drilling any finger holes.

9. Adjust window length and windway height until response is repeatable at low

and medium breath pressure.

10. Drill tone holes undersize from the foot upward.

11. Tune by gradual enlargement, recording final diameters in `validation.csv`.

12. Trim the foot only after the scale is stable.

13. Photograph the block, window, labium, and final hole layout for the build

log.

Stop Conditions

• Stop if the block leaks enough to change response after reinstalling.
• Stop if the labium edge chips or tears; make a window coupon before recutting

the body.

• Stop if the first tone requires high breath pressure only; fix voicing before

drilling tone holes.

validation.csv

Target/measured values, tolerance, environment, result, and tuning/build action log.

supplier-rfq.md

Supplier email/request-for-quote starter.

Supplier RFQ

Request

Please quote the following public-safe, non-proprietary instrument-build

materials or fabrication services.

Items

• Item: TBD
• Quantity: TBD
• Material/spec: TBD
• Tolerance: TBD
• Finish: TBD
• Lead time target: TBD

visual-bom-brief.md

Art direction for an image-forward visual BOM.

Visual BOM Brief

Create a single-page visual BOM after the first prototype is cut. Required

image panels:

• PVC proof body before window cutting.
• Removable block blanks and fitted block.
• Window/labium close-up.
• Hole-layout story stick.
• Tuning tools: tuner, caliper, drill index, files, wax.

Each row should include quantity, material, final dimensions, and which

validation row confirms the part.

andean-duct-flutes-starter.wl

Wolfram starter for physics, optimization, visualization, and validation.

(* Andean duct flute starter: open-pipe length and first-pass holes. *)

ClearAll["Global`*"];

cInPerSec = 13552;
a4 = 440;
fundamentalHz = 392.0;
boreIn = 0.625;
radiusIn = boreIn/2;
endCorrectionIn = 2*0.6*radiusIn;

targetHz[midi_] := a4*2^((midi - 69)/12);
centsError[measured_, target_] := 1200*Log[2, measured/target];
physicalLengthForHz[f_] := cInPerSec/(2*f) - endCorrectionIn;

scaleOffsets = {0, 3, 5, 7, 10, 12};
scaleTable = Table[
  With[{f = fundamentalHz*2^(offset/12)},
    <|
      "OffsetSemitones" -> offset,
      "TargetHz" -> f,
      "DistanceFromFootIn" -> physicalLengthForHz[fundamentalHz]*(fundamentalHz/f)
    |>
  ],
  {offset, scaleOffsets}
];

Dataset[scaleTable]

(* Validation reminder: duct/window response is empirical and must be measured
   before this model is used for a hardwood or bamboo body. *)

CHECKLIST.md

Project artifact.

Public-Ready Checklist

Readiness Level

• [ ] L0 Concept: target sound, family, and rough build method are documented.
• [ ] L1 Design: governing equations, assumptions, dimensions, BOM, and sourcing candidates are present.
• [ ] L2 Shop Packet: build sequence, drawings/briefs, cut list, validation checklist, hazards, and artifact paths are complete enough for careful builder review.
• [ ] L3 Validated Packet: validator passes, generated/rendered artifacts open, units are consistent, and sourceability/tolerance claims are checked.
• [ ] L4 Empirical Packet: measured build data, tuning deviations, correction loop, and catalog feedback are included.

Only L3 or L4 work should be described as build-ready.

Packet Completeness

• [ ] Replace `Andean Duct Flutes`, `L2 root-mode build packet for Andean duct flutes: pinkullo, tarka, and related fipple flutes.`, and other placeholders.
• [ ] Add cultural attribution and sources of inspiration.
• [ ] Replace placeholder photos with owned photos, renders, or honest public-safe placeholders.
• [ ] Fill `design.md` with instrument-specific governing equations and assumptions.
• [ ] Fill BOM, sourcing, cut list, validation, and family spec rows with non-placeholder values.
• [ ] Add OpenSCAD/SolidWorks/Wolfram handoff notes without pretending final CAD exists.
• [ ] Add drawings and a CNC/setup plan where applicable.
• [ ] Fill `resources.md` with public-safe provenance, education, maker, and license notes.
• [ ] Fill `jig-decision.md` for any make/order/buy/borrow fixture decisions.
• [ ] Run `instrument-maker-v4/scripts/validate_packet.py . --mode root --json`.
• [ ] Confirm no local absolute paths, private repo links, or frozen supplier-price claims.

Review Evidence

• [ ] PR body includes changed behavior/artifact, physics/manufacturing assumptions, validation run, known gaps, reviewer focus, and do-not-merge-until bar.
• [ ] Physics gate passed: model, assumptions, units, tuning targets, and sensitivity ranges are reviewable.
• [ ] Manufacturing gate passed: toolchain, materials, tolerances, cut lists/jigs/CAD, and assembly order are plausible.
• [ ] Safety gate passed: dust, finishes, adhesives, sharp tools, tension, heat/pressure/electrical risks, and workshop constraints are addressed.
• [ ] Artifact gate passed: BOM, sourcing, cut list, validation, risks, drawings/CAD briefs, and rendered/generated artifacts are present or gaps are named.
• [ ] Empirical gate passed: measurement plan, pass/fail criteria, tuning correction path, and catalog feedback destination are stated.

README.md

Project artifact.

Andean Duct Flutes

> L2 root-mode build packet for a small Andean duct-flute family: pinkullo,

> tarka, and related fipple flutes.


What This Is

This repository documents a contemporary workshop build packet for Andean

duct flutes: block-and-window flutes where a windway directs the player's air

jet across a labium. The first build target is a **G4 pinkullo-style

prototype** because it is large enough to make the duct geometry forgiving,

short enough for common stock, and useful as a reference before lower tarka

members are attempted.

The packet is intentionally **L2, not L3**. It is ready for review as a

shop-packet candidate, but it is not build-ready until the windway, window,

breath pressure, and tuning data are measured on a physical prototype.

Refs #1.

Design Overview

Why Duct Geometry Is The Center Of The Packet

The tube length equation only sizes the air column. The instrument will not

speak cleanly unless the duct and labium are tuned together:

• windway height starts near 0.040 in for the G4 prototype and is adjusted for

response, not volume;

• window length starts at 0.45 in and is filed after first-sound tests;
• labium ramp angle starts near 35 degrees, with a crisp edge and no torn grain;
• block fit must be airtight enough that breath energy exits through the

windway, not around the plug;

• breath pressure is logged as low/medium/high subjective bins until a manometer

test is added.

Packet Map

Build Order

1. Build PVC G4 proof-of-tune body and keep the duct block removable.

2. Establish repeatable first sound at low and medium breath pressure.

3. Drill tone holes undersize and tune from foot to head.

4. Record frequency and response data in `validation.csv`.

5. Transfer only the measured duct/window geometry to hardwood or bamboo.

Status

License

[CC BY 4.0](LICENSE) - engineering documentation only. This packet is a

contemporary workshop interpretation and is not a claim of cultural ownership.

family-spec.csv

Project artifact.

jig-decision.md

Project artifact.

Jig Decision

photo-shotlist.md

Project artifact.

Photo Shotlist

• Hero image of completed instrument or honest concept placeholder.
• Scale reference with ruler/calipers.
• Material blank before cutting.
• Key operations and jigs.
• Detail shots of acoustic features.
• Final validation setup.

resources.md

Project artifact.

Resources

Cultural Context

This packet treats Andean duct flutes as living Indigenous and regional

instruments, not generic "folk flutes." Public-facing writing should identify

the specific form being built when known, such as pinkullo or tarka, and avoid

claiming authenticity for a workshop prototype.

Engineering References To Gather Before L3

• Measured examples of pinkullo/tarka bore, window, and block geometry.
• Player demonstrations showing breath pressure and articulation.
• Photos of duct/window construction from makers who permit reference use.
• Temperature and humidity notes from the tuning session.

Related Repos

• `tonykoop/instrument-maker` for governing formulas and packet validation.
• `tonykoop/siku-zampona` for Andean provenance handling and pipe-array tuning

discipline.

• `tonykoop/flutes` for general wind-instrument measurement habits. NAF K2

corrections do not transfer to this duct-flute packet.

review-evidence.md

Project artifact.

Review Evidence

Refs #1.

Round 3 Scope

• Added an L2 root-mode build packet scaffold and hand-tuned it for Andean

duct-flute specifics: fipple block, windway, window/labium, breath pressure,

pentatonic-first scale validation, and PVC-to-hardwood/bamboo prototype path.

• This packet does not claim L3/build-ready status.

Gates Before Close

• Build and measure the G4 proof-of-tune body.
• Record actual bore ID, block reinstall repeatability, breath response, final

hole diameters, and cents error in `validation.csv`.

• Promote measured duct/window geometry before cutting a hardwood or bamboo

body.

risks.md

Project artifact.

Risks