Wind Tunnel Investigation of Airfoils Oscillating in Reverse Flow. Volume 1. Summary and Evaluation of Results

reportActive / Technical Report | Accession Number: AD0874374 | Open PDF

Abstract:

The report presents the results of an experimental investigation of the dynamic airloads on an airfoil Vertol 23010-1.58 immersed in reverse flow such as occurs on the retreating side of a helicopter rotor disc in forward flight. Forces and moments in two-dimensional flow were determined from airfoil differential pressures measured during pitching oscillation. Mach number, Reynolds number, and mean angle-of-attack ranges corresponded to those typically encountered under full-scale flight conditions. Frequencies of oscillation were varied between values corresponding to the 1rev and typical first elastic torsional frequency of rotor blades. Pitching oscillation was shown to postpone normal force and pitching moment stall to angles of attack well beyond static values. Large increases in dynamic CN and CM maxima due to reduced frequency and pitch rate effects were observed, while variations due to Mach number were found to be relatively small.

Author(s):
Gray, Lewis ; Dadone, Leo U. ; Gross, David W. ; Child, Richard F.
Author Organization(s):
BOEING VERTOL CO PHILADELPHIA PA
Descriptive Note:
Final rept.
Supplementary Note:
See also Volume 2, AD0874410. DOI: 10.21236/AD0874374
Pagination:
0088

Security Markings

DOCUMENT & CONTEXTUAL SUMMARY

Distribution:
Approved For Public Release
Distribution Statement:
Approved For Public Release; Distribution Is Unlimited.

RECORD

Collection: TR
Identifying Numbers
Report Number(s):
D8-2474-1, USAAVLABS-TR-70-4A
Contract/Grant Number(s):
DAAJ02-68-C-0064
Task Number(s):
1F162204A14231
Project Number(s):
DA-1-F-162204-A-142
Monitor Series:
TR-70-4A, USAAVLABS
 Subject Terms
Joint Capability Areas:
JCA_7.2.1_Mitigate Lethal Effects; JCA_7.2_Mitigate; JCA_7_Protection; JCA_8_Building Partnerships; JCA_5_Command and Control; JCA_8.2_Shape; JCA_3_Force Application; JCA_3.2_Engagement; JCA_1.3_Human Capital Management; JCA_1_Force Support; JCA_5.2_Understand; JCA_5.2.3_Share Knowledge and Situational Awareness; JCA_5.3_Planning; JCA_8.1_Communicate
Communities of Interest:
Air Platforms
Descriptor(s):
*AIRFOILS, *SECONDARY FLOW, AERODYNAMIC LOADING, ANGLE OF ATTACK, DAMPING, HELICOPTER ROTORS, OSCILLATION, PITCH(MOTION), ROTARY WINGS, STALLING, TWO DIMENSIONAL FLOW
Field(s)/Group(s):
Aerodynamics, Fluid Mechanics
Report Date:
1970 Mar 01