ISO 5109-2023 PDF

Full title and description

ISO 5109:2023 — Evaluation method for the resonance frequency of the multi-copter UA (unmanned aircraft) by measurement of rotor and body frequencies. This International Standard specifies a measurement- and evaluation-based method intended to identify and avoid resonance that can occur when the natural frequency of a multi‑copter airframe coincides with rotor rotational frequencies.

Abstract

This document provides a method for evaluating the resonance vibration frequency of multi‑copter unmanned aircraft (UA). It specifies how to measure rotor and body frequencies and how to design the UA to avoid resonance produced by coincidence of the UA body natural frequency and the rotor rotational frequency. The standard is applicable to multi‑copter UAs with a maximum mass below 150 kg.

General information

• Status: Published.
• Publication date: 13 July 2023 (Edition 1, 2023-07).
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 49.020 (Aeronautics and astronautics).
• Edition / version: Edition 1 (2023).
• Number of pages: 9.

Scope

Specifies an evaluation method for the resonance vibration frequency of multi‑copter unmanned aircraft by measurement of rotor and body frequencies and provides guidance for designing UAs to avoid resonance caused by coincidence of the airframe natural frequency and rotor rotational frequency. The document applies to multi‑copter UAs with maximum mass less than 150 kg.

Key topics and requirements

• Measurement of rotor rotational frequencies and body (structural) natural frequencies.
• Evaluation procedure to determine potential resonance conditions arising from frequency coincidence.
• Design guidance and acceptance criteria for avoiding or mitigating resonance in multi‑copter designs.
• Applicability limit: multi‑copter UAs with mass below 150 kg.
• Intended use as a test / assessment method for designers, test laboratories and certification activities.

Typical use and users

Used by multi‑copter/UAV manufacturers and designers during structural and dynamic design phases, test laboratories performing vibration and resonance assessments, integrators and system engineers validating flight‑critical mechanical dynamics, and certification authorities or conformity assessment bodies evaluating structural vibration safety. It is also useful for R&D teams addressing rotor–airframe interaction and for maintenance organizations concerned with vibration‑related damage or airworthiness.

Related standards

Relevant ISO and related documents include categorization/classification of civil unmanned aircraft systems (ISO 21895 series) and broader vibration test methods for small and light UAS (for example ISO 5309:2023). Other developing deliverables addressing multi‑copter docking systems and related performance requirements are produced under ISO/TC 20/SC 16.

Keywords

multi‑copter; unmanned aircraft (UA); UAV; resonance frequency; rotor frequency; vibration; structural natural frequency; frequency coincidence; ISO 5109; ISO/TC 20/SC 16.

FAQ

Q: What is this standard?

A: ISO 5109:2023 is an ISO International Standard that defines a measurement and evaluation method to identify resonance vibration risks in multi‑copter unmanned aircraft by comparing rotor rotational frequencies with the airframe's natural (body) frequencies.

Q: What does it cover?

A: It covers procedures for measuring rotor and structural (body) frequencies, evaluating the potential for frequency coincidence (resonance), and guidance for design or mitigation to avoid harmful resonance. It is applicable to multi‑copter UAs with a maximum mass under 150 kg.

Q: Who typically uses it?

A: UAV/multi‑copter designers and manufacturers, test and vibration laboratories, system integrators, R&D teams working on rotor‑airframe dynamics, and certification or conformity assessment bodies reviewing structural vibration safety.

Q: Is it current or superseded?

A: Current — published 13 July 2023 as Edition 1 (ISO 5109:2023). Users should check ISO and national standards bodies for any later confirmations, amendments or revisions.

Q: Is it part of a series?

A: It sits within the body of ISO work on civil unmanned aircraft (ISO/TC 20/SC 16). It is complementary to other documents such as ISO 21895 (categorization/classification of civil UAS) and ISO 5309 (vibration test methods for small and light UAS).

Q: What are the key keywords?

A: Multi‑copter, unmanned aircraft, UAV, resonance frequency, rotor frequency, vibration testing, structural dynamics, frequency coincidence, ISO 5109.