# FPV rotor audio

Retrieved and adapted on 2026-10-20.

## Recording and permission

- **FPV Drone Flight 2**, qubodup: https://freesound.org/people/qubodup/sounds/854465/
- Public high-quality preview: https://cdn.freesound.org/previews/854/854465_71257-hq.mp3
- Freesound identifies this sound as **CC0 1.0 Universal**: https://creativecommons.org/publicdomain/zero/1.0/
- Original recording: **Maneuver Battle Lab Quarterly Drone Race EPK(H)**, Brandon Dorrill, Fort Benning Public Affairs Office, 2026-04-17: https://www.dvidshub.net/video/1004667/maneuver-battle-lab-quarterly-drone-race-epkh
- DVIDS marks the original as public domain. No endorsement by the recordist, Freesound, DVIDS or the U.S. Army is implied.
- The source describes an FPV onboard recording but does not specify propeller diameter or motor model. It is not represented as a verified recording of a 5-inch aircraft or the AE2207 V2.

## Changes

Two steady portions were extracted: 0.78–1.50 seconds (cruise) and 4.78–5.44 seconds (loaded timbre). A second-order 260 Hz high-pass reduces microphone/airframe rumble; a second-order 7.2 kHz low-pass removes excessive hiss. Estimated shaft-frequency peaks, 205.5 Hz and 187.4 Hz, were resampled to a shared 210 Hz reference (12,600 rpm), with a 90 ms wrap crossfade and RMS normalization to 0.24. Each result is mono 48 kHz 16-bit PCM WAV. Neither the recording nor processing is a calibrated acoustic measurement.

The simulator crossfades the two recordings, changes playback rate with throttle and adds a quiet generated broadband airflow layer. Its reference RPM curve from 30–100% uses existing manufacturer data for AXISFLYING AE2207 V2 2100KV / BB4943.5 (13,824–35,710 rpm). Below 30% uses estimated idle/intermediate points. The sound is a design approximation and does not claim to measure the simulated aircraft's motor RPM.

Manufacturer reference: https://www.axisflying.com/products/5inch-brushless-economic-fpv-motor-ae2207-v2
Archived values in the project: `data/fpv-parts/motors.json`, `ae2207-v2-1`.

General acoustic reference, used for interpretation only, not copied into the audio: Intaratep et al., *Experimental Study of Quadcopter Acoustics and Performance at Static Thrust Conditions*, AIAA 2016-2873, https://www.bu.edu/ufmal/files/2016/07/aiaa-2016-2873.pdf . Its aircraft is a Phantom II, not a 5-inch FPV quad. It documents shaft/blade-passage tones, harmonics and broadband noise.

The two local loops total 106988 bytes. They load once, when sound is enabled; flight and muted use do not require an audio download. There are no remote audio requests at runtime.

## SHA-256

Source MP3: `bd12dcb438a94a88958b738591660401a7aced876efdd01d4b1a7b53c8627609`

- `prop-cruise.wav`: `8ff980a2bf81ab11002450f8c0dbe63a81c11cb7cddf324909b659f0554f30f1`
- `prop-loaded.wav`: `ac17254d9730c53fd19ef9c7a3d823402debd2b6ebf243bffa1bbc71fe737748`