Experimental study of propeller-aircraft run-up noise
Bibliographic record
Abstract
Measurements were made of the characteristics of the noise radiated by a Beechcraft 1900D twin-propeller aircraft during engine run-up.The objective was to determine the feasibility of controlling this noise using active noise control.Total noise levels varied with aircraft heading from 103 to 112 dB (100 to 109 dBA) at 73 m from the aircraft.Noise directivity plots were generated.Levels at the nearest community 3 km away varied from 74 to 77 dB (62 to 66 dBA).Near the aircraft the noise spectra comprised a series of equally-high peaks at the 112-Hz fundamental frequency and its multiples.In the community, the three low est peaks dominated the A-weighted spectrum, with higher-frequency peaks being progressively attenuated.A coherence analysis was performed on the noises measured at 73 m and 98 m from the aircraft.The inser tion loss of a blast fence near the run-up area was estimated from run-up noise measurements made on both sides of the fence.The insertion loss varied from 4 to 13 dB and was greatest at mid frequencies. SOMMAIREDes mesures ont t faites des caractristiques du brait rayonn par un avion deux hlices -un Beechcraft 1900D -durant des tests d'acclration des moteurs ('run-up').L'objectif a t de dterminer s'il serait fais able de controller ce brait par un systme de contrle actif.Les niveaux totals du brait ont varis avec la direction de 103 112 dB (de 100 109 dBA) 73 m de l'avion.La directivit du bruit rayonn a t dter mine.Dans la communaut voisine la plus proche, environ 3 km de l'avion, les niveaux ont varis entre 62 et 66 dBA.Proche de l'avion, le spectre du brait a consist d'une srie d'arrts d'amplitudes semblables correspondant la frquence fondamentale de 112 Hz et de ses harmoniques.Dans la communaut voisine, les trois arrts les plus bas ont domins le spectre; les arrts de plus hautes frquences ont ts de plus en plus attnus.Un analyse de cohrence a t faite sur les bruits mesurs 73 m et 98 m de l'avion.La perte par insertion d'une clture acoustique proche du site de test, estime l'aide de mesures prises des deux cts de la clture, a varie de 4 13 dB et a te le plus lve moyenne frquence.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".