NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Initial Characterization of the TiltRotor Aeroelastic Stability TestbedThis paper discusses the initial wind tunnel test of the TiltRotor Aeroelastic Stability Testbed (TRAST). TRAST is a generic tiltrotor testbed developed in collaboration between NASA and the Army. Ultimately, this test was a checkout of the model systems, functionality and familiarization, but also obtained subcritical whirl-flutter data in the terms of frequency and damping. Flutter data include two main configurations with different pitch spring stiffness, referred to as 4k and 8k, that were tested at various rotor speeds and airspeeds at the NASA Langley Transonic Dynamics Tunnel. The test included two modes of drivetrain operation: powered and windmilling. However, powered mode of operation was only conducted with the 8k pitch spring. This test reinforced the traditional knowledge of whirl-flutter trends such as flutter speed would decrease with an increase in rotor speed. The critical mode consistently being the wing vertical bending mode. The chord mode as expected was not affected by the pitch spring and was likely to go unstable at a tunnel airspeed slightly beyond the wing vertical bending mode. There were also test specific challenges such as the TRAST modal damping was more sensitive to temperature and amplitude motor than was expected. This test gathered valuable data on the baseline characterization of TRAST, how to improve the model and test practices for future wind tunnel testing. Additionally, a new more automated method for experimental subcritical damping determination based on the Stockwell transform has been demonstrated that may lead to more consistent whirl-flutter stability boundaries.
Document ID
20230007174
Acquisition Source
Langley Research Center
Document Type
Presentation
Authors
Andrew Kreshock
(United States Army Research Laboratory Adelphi, Maryland, United States)
Robert Thornburgh
(United States Army Research Laboratory Adelphi, Maryland, United States)
Matthew Wilbur
(United States Army Research Laboratory Adelphi, Maryland, United States)
Hao Kang
(United States Army Research Laboratory Adelphi, Maryland, United States)
David J Piatak
(Langley Research Center Hampton, Virginia, United States)
Martin Sekula
(Langley Research Center Hampton, Virginia, United States)
Date Acquired
May 8, 2023
Publication Date
May 17, 2023
Subject Category
Research and Support Facilities (Air)
Meeting Information
Meeting: 79th Annual Vertical Flight Society (VFS) Forum & Technology Display
Location: West Palm Beach, FL
Country: US
Start Date: May 16, 2023
End Date: May 18, 2023
Sponsors: The Vertical Flight Society
Funding Number(s)
WBS: 664817.02.07.04.03.02
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
Technical Review
Single Expert
Keywords
whirl flutter
wind tunnel testing
No Preview Available