NOISE SURVEY HU-1A HELICOPTER WITH MODIFIED EXHAUST SYSTEM

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Abstract:

Noise levels of Army HU-1A helicopters 9-1632 equipped with a modified exhaust system and 58-2080 standard configuration were recorded under similar operating and ambient conditions. Some difference exists in the 200 ft directivity patterns of the aircraft in hover, along with an increase in high frequency noise in take-off and landing. The latter may be due to pilot techniques in achieving the requirements of Test 2. Except for these, however, sound pressure levels of the aircraft, under similar operating conditions, are considered the same. Other differences lie within the envelope of repeatability. It is concluded that the modified exhaust system of HU-1A No. 9- 1632 does not significantly affect the acoustic characteristics of the aircraft.

Author(s):
Spencer, R. H. ; Sternfeld, Jr, H.
Author Organization(s):
BOEING CO MORTON PA VERTOL DIV
Pagination:
0050

Security Markings

DOCUMENT & CONTEXTUAL SUMMARY

Distribution:
Approved For Public Release, Document Partially Illegible
Distribution Statement:
Approved For Public Release; Distribution Is Unlimited. Document Partially Illegible.

RECORD

Collection: TR
Identifying Numbers
Report Number(s):
R-247, TCREC-TR-61-92
Contract/Grant Number(s):
DA-44-177-TC-562
Project Number(s):
DA-9R38-01-017-54
Monitor Series:
TR-61-92, TRECOM
 Subject Terms
Joint Capability Areas:
JCA_5_Command and Control; JCA_6_Net Centric; JCA_6.3.3_Spectrum Management; JCA_6.4.1_Secure Information Exchange; JCA_6.3_Net Management; JCA_6.4_Information Assurance; JCA_1_Force Support; JCA_3.2_Engagement; JCA_3_Force Application; JCA_5.1.3_Foster Organizational Collaboration; JCA_5.1_Organize; JCA_3.2.1_Kinetic Means; JCA_5.2_Understand; JCA_1.2_Force Preparation; JCA_5.3_Planning; JCA_1.2.5_Lessons Learned; JCA_4.6_Engineering
Modernization Areas:
Microelectronics; Directed Energy
Communities of Interest:
Air Platforms
Descriptor(s):
*AIRCRAFT ENGINE NOISE, ACOUSTIC PROPERTIES, AIRCRAFT, AIRCRAFT NOISE, CONFIGURATIONS, ENVELOPE(SPACE), EXHAUST DIFFUSERS, EXHAUST SYSTEMS, FLIGHT TESTING, FREQUENCY, HELICOPTERS, HOVERING, LANDING, LEVEL(QUANTITY), MEASUREMENT, NOISE, OPERATION, PATTERNS, PILOTS, PRESSURE, REQUIREMENTS, SOUND PRESSURE, SURVEYS, TABLES(DATA)
Field(s)/Group(s):
Acoustics
Keyword(s):
H 1 AIRCRAFT
Report Date:
1961 Jul 01