Full-Span Tiltrotor Aeroacoustic Model (FS TRAM)
Overview and Initial Testing
Megan S. McCluer
NASA Ames Research Center
Moffett Field, CA
Jeffrey L. Johnson
Aerospace Computing, Inc.
Mountain View, CA
The Full-Span Tiltrotor Aeroacoustic Model (FS TRAM) is a dual-rotor, powered wind tunnel model with extensive
instrumentation for measurement of structural and aerodynamic loads.
The model has been developed to investigate
tiltrotor aeromechanics and to generate a comprehensive database for validating analyses, as well as a research platform
for studying current and future tiltrotor designs.
This paper describes the Full-Span TRAM test stand and the first set of
data obtained at the NASA Ames Research Center 40- by 80-Foot Wind Tunnel test conducted in late 2000. Limited
results are presented and recommendations for future testing are provided.
This model has been established as a
valuable national asset for tiltrotor research.
The tiltrotor is a versatile aircraft which can fly with the
speed and range of a turboprop airplane while also having
the vertical take-off and landing capability of a
Wind tunnel testing of tiltrotor models
increases the understanding of tiltrotor aerodynamics,
dynamics, performance, and acoustics, and enables the
development of advanced computational design tools.
Wind tunnel data can also be used to improve simulation
models and investigate detailed conditions that are too
arduous to obtain in flight test.
The Full-Span Tilt Rotor
Aeroacoustic Model (FS TRAM), shown in Figure 1, is a
1/4-scale representation of the V-22 Osprey aircraft
2) and was tested at the NASA Ames Research
Center 40- by 80-Foot Wind Tunnel in late 2000. The
first full-span test served primarily as a complete system
build-up and checkout.
Model, motor, and rotor system
controls and measurements were built, installed, and
Limited test data were obtained on rotor
performance, blade structural loads, and wing static
Some laser light sheet flow visualization
images and acoustics data were also obtained.
testing will provide the full-span tiltrotor data the
rotorcraft community requires, since isolated and semi-
span model testing do not fully address all tiltrotor
The long-term goal of the FS
TRAM is to be a tiltrotor research tool for future testing
by the U.S. industry and Government.
Presented at the American Helicopter Society Aerodynamics,
Acoustics, and Test and Evaluation Technical Specialists’
Meeting, San Francisco, CA, January 23-25, 2002.
© 2002 by the American Helicopter Society International, Inc.
All rights reserved.
The Full-Span TRAM mounted in the
NASA Ames 40- by 80-Foot Wind Tunnel.
The V-22 Osprey tiltrotor aircraft during
shipboard operational evaluations. (U.S. Navy Photo)