{ "model": { "rank": 4952, "code": "thing-q160669", "model_id": "vr.tr.mach-number", "name": "Mach number", "purpose": "Let an agent handle Mach numbers by speed, local conditions and flow regime, and convert to speeds correctly.", "family": "Thing Registry", "category": "Cross-cutting context", "status": "research-draft", "kind": "thing", "plane": "XCT", "domain": "XCT.REL", "industry": "", "version": "", "url": "/models/thing/q160669/", "tier": 2, "score": 71, "payload": { "layer": "wikidata", "aliases": [ "critical Mach number" ], "aliasCount": 1, "merged": 1, "knownIn": 71, "facets": null, "markers": [], "lexicalClass": "", "senseRank": null, "alsoRegisteredAs": null, "source": { "dataset": "wikidata", "item": "Q160669", "url": "https://www.wikidata.org/wiki/Q160669", "license": "CC0 1.0" } }, "research": { "vercy": "1.0-draft", "publication": { "status": "research-draft", "adjudicationStatus": "unreviewed", "publishableCanonical": false, "generatedAt": "2026-09-11T07:03:19Z", "providers": [ "Claude" ], "breadth": "written by Claude from model knowledge without web access - no source was read, every claim is a lead to verify", "pass": 2, "wave": 1, "engine": "claude" }, "metaModel": { "id": "THING-Q160669", "registryId": "vr.tr.mach-number", "name": "Mach number", "version": "0.2.0-wave.1", "entryKind": "thing", "family": "Thing Registry", "domain": [ "XCT.REL" ], "status": "research-draft" }, "canonicalUrl": "https://ver.cy/models/thing/q160669/", "model": { "registry_id": "vr.tr.mach-number", "name": "Mach number", "purpose": "Let an agent handle Mach numbers by speed, local conditions and flow regime, and convert to speeds correctly.", "definition": "A dimensionless quantity equal to the ratio of the speed of a flow or object to the local speed of sound; Mach 1 is sonic, above 1 supersonic, above about 5 hypersonic.", "what_it_is_for": "Characterising compressible flow in aerodynamics.", "affordances": [ "compute from speed and sound speed", "classify flow regime", "design for critical Mach number", "convert to km/h at given conditions" ], "distinguishing_features": [ "Dimensionless ratio", "Depends on local temperature", "Defines compressibility effects", "Not a fixed speed" ], "appearance": "A number, often displayed on aircraft machmeters.", "visual_identification": [ "Notation M or Ma", "Flow regimes: subsonic, transonic, supersonic, hypersonic", "Critical Mach number is a design limit" ], "physical_properties": [ { "quantity": "speed of sound at sea level (15 C)", "typical_range": "about 340", "unit": "m/s", "note": "ISA" }, { "quantity": "hypersonic threshold", "typical_range": "about 5", "unit": "Mach", "note": "convention" } ], "families_and_kinds": [ "subsonic flow", "transonic flow", "supersonic flow", "hypersonic flow", "critical Mach number" ], "related_models": [ { "relation": "is a kind of", "target": "dimensionless quantity", "why": "category" }, { "relation": "uses", "target": "speed of sound", "why": "reference" }, { "relation": "is used in", "target": "aerodynamics", "why": "field" }, { "relation": "relates to", "target": "speed", "why": "quantity" } ], "identifiers": [ { "scheme": "symbol", "value_or_pattern": "M or Ma", "note": "notation" } ], "standards_and_regulation": [ "ISO 2533 standard atmosphere", "Supersonic flight restrictions over land" ], "failure_modes_and_hazards": [ "Converting Mach to speed with the wrong sound speed", "Sonic boom effects" ], "in_scope": [], "out_of_scope": [], "characteristics": [] }, "sources": [], "structure": { "bundles": [ { "id": "value", "name": "Value", "description": "Computing Mach.", "rationale": "Mach depends on conditions.", "layers": [ { "id": "compute", "name": "Compute", "description": "Ratio.", "findings": [ { "id": "compute-finding", "name": "Compute", "description": "Mach value.", "questions": [ { "text": "What is the Mach number for this speed and temperature?", "kind": "measurement" }, { "text": "Which speed of sound was used?", "kind": "provenance" } ] } ] }, { "id": "conversion", "name": "Conversion", "description": "To speed.", "findings": [ { "id": "conversion-finding", "name": "Conversion", "description": "Conversion.", "questions": [ { "text": "What speed does this Mach correspond to at this altitude?", "kind": "measurement" }, { "text": "Under which atmosphere model?", "kind": "provenance" } ] } ] } ] }, { "id": "regime", "name": "Regime", "description": "Flow type.", "rationale": "Regimes differ physically.", "layers": [ { "id": "class", "name": "Class", "description": "Subsonic to hypersonic.", "findings": [ { "id": "class-finding", "name": "Class", "description": "Flow regime.", "questions": [ { "text": "Which flow regime applies?", "kind": "definition" }, { "text": "What effects appear?", "kind": "definition" } ] } ] }, { "id": "shock", "name": "Shocks", "description": "Shock waves.", "findings": [ { "id": "shock-finding", "name": "Shocks", "description": "Shock waves.", "questions": [ { "text": "Do shock waves form?", "kind": "boundary" }, { "text": "Where?", "kind": "definition" } ] } ] } ] }, { "id": "design", "name": "Design", "description": "Aircraft.", "rationale": "Design limits use Mach.", "layers": [ { "id": "critical", "name": "Critical Mach", "description": "Limit.", "findings": [ { "id": "critical-finding", "name": "Critical", "description": "Critical Mach number.", "questions": [ { "text": "What is the critical Mach number of this wing?", "kind": "measurement" }, { "text": "What happens beyond it?", "kind": "boundary" } ] } ] }, { "id": "limits", "name": "Limits", "description": "Operating limits.", "findings": [ { "id": "limits-finding", "name": "Limits", "description": "Operating limits.", "questions": [ { "text": "What is the maximum operating Mach number?", "kind": "measurement" }, { "text": "From which flight manual?", "kind": "provenance" } ] } ] } ] }, { "id": "environment", "name": "Environment", "description": "Sonic boom.", "rationale": "Supersonic flight has effects.", "layers": [ { "id": "boom", "name": "Sonic boom", "description": "Noise.", "findings": [ { "id": "boom-finding", "name": "Boom", "description": "Sonic boom.", "questions": [ { "text": "Will the flight produce a sonic boom on the ground?", "kind": "boundary" }, { "text": "How loud?", "kind": "measurement" } ] } ] }, { "id": "rules", "name": "Rules", "description": "Restrictions.", "findings": [ { "id": "rules-finding", "name": "Rules", "description": "Flight rules.", "questions": [ { "text": "Is supersonic flight allowed here?", "kind": "boundary" }, { "text": "Under which regulation?", "kind": "provenance" } ] } ] } ] } ] }, "openQuestions": [ "Should flow regimes be separate entries?", "How should atmosphere models be linked?", "How should critical Mach be recorded per aircraft?" ], "statistics": { "bundles": 4, "layers": 8, "findings": 8, "questions": 16 } }, "draft": { "generator": "vr.draft.v3", "status": "draft-generated", "researched": false, "archetype": "abstract concept", "method": "Written from the archetype playbook - what this kind of thing needs beyond identity and provenance - and from the structure that recurred across 6,333 models already researched by two engines. Applied to this entry by rule. No source was read for this thing and no claim here is researched. This entry carries no facets of its own, so they were inferred from its domain - a guess about a whole domain applied to one thing.", "facetsInferred": true, "nextPass": "A researcher replaces this draft with a sourced specification. Treat every sentence below as a proposal to argue with.", "purpose": "Give an agent a durable, checkable way to recognise a Mach number, record what state it is in, and decide what may be done with it.", "whatItIs": "Let an agent handle Mach numbers by speed, local conditions and flow regime, and convert to speeds correctly.", "characteristics": { "substance": "abstract", "origin": "conceptual", "agency": "inert" }, "whatYouCanDoWithIt": [ "observed and measured" ], "distinguishingFeatures": [ "Names folded into this entry, which a task may need to split apart again: critical Mach number.", "1 finer distinctions are held as aliases rather than separate entries, because telling them apart needs a task that asks for it.", "Described in 71 Wikipedia languages, which is a measure of how widely the thing is known, not of how important it is." ], "openQuestionsForResearch": [ "Which of the bundles below does a real task actually need, and which are ceremony?", "What does this thing have that the facets do not capture at all?", "Which neighbouring kind is most often confused with a Mach number, and on what evidence are they told apart?" ], "whatItIsMadeOf": "an abstraction with no physical instance", "physicalCharacter": [ "Does nothing on its own; everything it does, something else did to it.", "These come from the domain this entry sits in rather than from the entry itself, so treat them as a first guess about the whole domain applied to one thing." ], "whatCanBeDoneWithIt": [ "observe it, measure it, record its state" ], "howItIsRecognised": [ "Nothing to see. What is recognised is an instance of it, and which instances count is exactly what is argued about." ], "relatedModels": [ { "relation": "covers", "note": "Finer kinds folded into this entry because telling them apart needs a task that asks for it. Each is a model waiting to be split out when one does.", "targets": [ "critical Mach number" ] } ], "standing": "Described in 71 Wikipedia languages, which measures how widely it is written about rather than how important or how common it is. 1 finer distinctions are held inside this entry as names rather than as separate models.", "structure": { "bundles": [ { "id": "identity-and-classification", "name": "Identity, naming and classification", "description": "How an agent tells one Mach number from another, and a Mach number from things that resemble it.", "rationale": "Recognition comes before every other claim. Without stable identity nothing else in the model can be trusted to be about the same thing twice.", "layers": [ { "id": "naming-and-identifiers", "name": "Names and identifiers", "description": "The names this thing goes by and the identifiers that survive translation and time.", "findings": [ { "id": "preferred-name-and-aliases", "name": "Preferred name, aliases and local names", "description": "Which name to use, which names mean the same thing, and which merely sound similar.", "questions": [ { "id": "preferred-name-and-aliases-q01", "text": "What identifies and describes the name of a Mach number, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "preferred-name-and-aliases-q02", "text": "Who or what asserted this about the name of a Mach number, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "preferred-name-and-aliases-q03", "text": "What may an agent decide or do once the name of a Mach number is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] }, { "id": "stable-identifiers", "name": "Stable identifiers and external keys", "description": "Identifiers that keep pointing at this kind of thing across systems and languages.", "questions": [ { "id": "stable-identifiers-q01", "text": "What identifies and describes an identifier for a Mach number, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "stable-identifiers-q02", "text": "Who or what asserted this about an identifier for a Mach number, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "stable-identifiers-q03", "text": "What may an agent decide or do once an identifier for a Mach number is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] }, { "id": "classification-and-granularity", "name": "Classification and granularity", "description": "Where a Mach number sits among kinds, and how finely a task needs to cut it.", "findings": [ { "id": "kind-and-parents", "name": "Kind, parents and neighbouring kinds", "description": "The classes this thing belongs to and the ones it is next to.", "questions": [ { "id": "kind-and-parents-q01", "text": "What identifies and describes the kind of a Mach number, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "kind-and-parents-q02", "text": "Who or what asserted this about the kind of a Mach number, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "kind-and-parents-q03", "text": "What may an agent decide or do once the kind of a Mach number is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] }, { "id": "distinguishing-features", "name": "Distinguishing features", "description": "What separates a Mach number from the things most often confused with it.", "questions": [ { "id": "distinguishing-features-q01", "text": "What identifies and describes what distinguishes a Mach number, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "distinguishing-features-q02", "text": "Who or what asserted this about what distinguishes a Mach number, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "distinguishing-features-q03", "text": "What may an agent decide or do once what distinguishes a Mach number is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] } ] }, { "id": "state-and-lifecycle", "name": "State and lifecycle", "description": "The states a Mach number passes through and the events that move it between them.", "rationale": "Most decisions about a thing depend on what state it is in now, which is a claim with a time on it, not a property.", "layers": [ { "id": "lifecycle-stages", "name": "Lifecycle stages", "description": "From coming into existence to ceasing to be one of these.", "findings": [ { "id": "stages-and-transitions", "name": "Stages and transitions", "description": "The stages worth naming and what moves a Mach number between them.", "questions": [ { "id": "stages-and-transitions-q01", "text": "What identifies and describes the lifecycle of a Mach number, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "stages-and-transitions-q02", "text": "Who or what asserted this about the lifecycle of a Mach number, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "stages-and-transitions-q03", "text": "What may an agent decide or do once the lifecycle of a Mach number is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] }, { "id": "observations-and-status", "name": "Observations and current status", "description": "What is observed about a Mach number, how often and by whom.", "findings": [ { "id": "observation-record", "name": "Observation record", "description": "How an observation of a Mach number is recorded so that it can be superseded rather than overwritten.", "questions": [ { "id": "observation-record-q01", "text": "What identifies and describes an observation of a Mach number, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "observation-record-q02", "text": "Who or what asserted this about an observation of a Mach number, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "observation-record-q03", "text": "What may an agent decide or do once an observation of a Mach number is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] } ] }, { "id": "definitions-in-contest", "name": "Definitions and who holds them", "description": "What Mach number is taken to mean, and by whom.", "rationale": "When a field disagrees about a concept, the disagreement is the content. A model that picks one definition silently destroys the information.", "layers": [ { "id": "competing-definitions", "name": "Competing definitions", "description": "The main readings and the traditions behind them.", "findings": [ { "id": "definition-map", "name": "Definitions and their holders", "description": "Each definition with the school or body that holds it.", "questions": [ { "id": "definition-map-q01", "text": "Which definitions of Mach number are in use, and which tradition or body holds each?", "kind": "definition" }, { "id": "definition-map-q02", "text": "What turns on the difference between them in practice?", "kind": "boundary" } ] } ] }, { "id": "operationalisation", "name": "Operationalisation", "description": "How it is measured or applied when it has to be.", "findings": [ { "id": "operational-record", "name": "Measures and proxies", "description": "Instruments and indicators used to stand in for it.", "questions": [ { "id": "operational-record-q01", "text": "How is Mach number operationalised or measured in practice, and by what instrument?", "kind": "measurement" }, { "id": "operational-record-q02", "text": "What does that operationalisation leave out, and when does that matter?", "kind": "boundary" } ] } ] } ] }, { "id": "instances-and-use", "name": "Instances, use and consequence", "description": "What counts as an instance of Mach number and what follows from calling something that.", "rationale": "Applying a concept is an act with consequences, so a model must say what the label licenses and what it does not.", "layers": [ { "id": "instances", "name": "What counts as an instance", "description": "Clear cases, borderline cases and non-cases.", "findings": [ { "id": "instance-tests", "name": "Tests for an instance", "description": "What would settle whether something falls under it.", "questions": [ { "id": "instance-tests-q01", "text": "What would settle whether something is an instance of Mach number?", "kind": "boundary" }, { "id": "instance-tests-q02", "text": "Which borderline cases are argued about, and on what grounds?", "kind": "definition" } ] } ] }, { "id": "consequence", "name": "Consequence of application", "description": "Rights, duties or decisions that follow from the label.", "findings": [ { "id": "consequence-record", "name": "What the label licenses", "description": "What an agent may do once something is classified this way.", "questions": [ { "id": "consequence-record-q01", "text": "What follows practically once something is treated as Mach number?", "kind": "action" }, { "id": "consequence-record-q02", "text": "What must an agent not infer from the label alone?", "kind": "action" } ] } ] } ] }, { "id": "provenance-and-evidence", "name": "Provenance, evidence and time", "description": "Where every claim about a Mach number came from and when it held.", "rationale": "A claim without a source and a time cannot be superseded, only overwritten, and an agent that overwrites loses the ability to explain itself.", "layers": [ { "id": "source-and-authority", "name": "Source and authority", "description": "Who said it, on what evidence, and how strongly.", "findings": [ { "id": "claim-provenance", "name": "Claim provenance and confidence", "description": "The authority behind each claim about a Mach number and how confident it is.", "questions": [ { "id": "claim-provenance-q01", "text": "What identifies and describes a claim about a Mach number, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "claim-provenance-q02", "text": "Who or what asserted this about a claim about a Mach number, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "claim-provenance-q03", "text": "What may an agent decide or do once a claim about a Mach number is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] }, { "id": "time-and-versions", "name": "Time, versions and supersession", "description": "When a claim was true, when it was learnt, and what replaced it.", "findings": [ { "id": "validity-and-supersession", "name": "Validity period and supersession", "description": "How an old claim about a Mach number is retired without being erased.", "questions": [ { "id": "validity-and-supersession-q01", "text": "What identifies and describes the validity of a claim about a Mach number, and in what units or vocabulary?", "kind": "definition", "answer_data": [ "identifiers", "types and classes", "values with units", "explicit unknowns" ] }, { "id": "validity-and-supersession-q02", "text": "Who or what asserted this about the validity of a claim about a Mach number, by which method, and when was it true?", "kind": "provenance", "answer_data": [ "authority", "method", "evidence", "event time", "knowledge time" ] }, { "id": "validity-and-supersession-q03", "text": "What may an agent decide or do once the validity of a claim about a Mach number is known, and what must it refuse?", "kind": "action", "answer_data": [ "permitted actions", "preconditions", "refusals", "escalation" ] } ] } ] } ] } ] }, "statistics": { "bundles": 5, "layers": 10, "findings": 12, "questions": 32 } } } }