Overview of a Comprehensive MD530F
Acoustic Flight Test
† * *
James Stephenson Kyle Pascioni Mary Houston
† *
Colin Stutz Preston Martin
† U.S. Army Combat Capabilities Development Command Aviation & Missile Center * NASA Langley Research Center st Vertical Flight Society’s 81 Annual Forum & Technology Display Virginia Beach, VA 21 May 2025 st VFS 81 Annual Forum & Technology Display Overview of a Comprehensive MD530F Acoustic Flight Test
Motivation and objectives
Motivation
There is a need to develop measurement techniques and data processing
methods to characterize AAM/UAM and FVL aircraft
Objectives
• Explore snapshot array designs • Increasing flight test efficiency using DoE methods • A cquiring phased array data for rotating source separation and localization • Determine appropriate methods to investigate unsteady flight st Overview of a Comprehensive MD530F Acoustic Flight Test VFS 81 Annual Forum & Technology Display 2
The team
Additional support • Oliver Wong • Shawn Naigle • Tom Maier NASA • Jacob Wilson Kyle Pascioni • Noah Schiller Mary Houston • Benny Lunsford Colin Stutz • Michael Doty Max Reid • Stan Mason • Nikolas Zawodny • Tony Humphreys Helicopter Technology Company US Army DEVCOM AvMC Jay Wigginton - Pilot James Stephenson Charles Dean – Chief Engineer Preston Martin Jack Rajcic Sierra Army Depot Gary Budorf Analytical Mechanics Associates Margarita Gonzalez - Venegas Brian Cicerone Jeffrey Davis Michael Foley David Ridgway Michael Gray st Overview of a Comprehensive MD530F Acoustic Flight Test VFS 81 Annual Forum & Technology Display 3
Test aircraft
MD530F Helicopter
8.38 m diameter, 39.75 Hz BPF 5/rev tachometer 1.55 m diameter, 94.9 Hz BPF 3,550 lb (1,520 kg) take - off weight 1,720 lb (780 kg) empty weight st Overview of a Comprehensive MD530F Acoustic Flight Test VFS 81 Annual Forum & Technology Display 4
Test aircraft
MD530F Helicopter
8.38 m diameter, 39.75 Hz BPF 5/rev tachometer Test at a glance: Amedee Airfield, Sierra Army Depot July 7 - July 29, 2024 6 days of testing 1.55 m diameter, 94.9 Hz BPF 11 sorties 21 flight hours 476 test points 3,550 lb (1,520 kg) take - off weight Level speed sweep, ascents, descents, maneuvers 1,720 lb (780 kg) empty weight st Overview of a Comprehensive MD530F Acoustic Flight Test VFS 81 Annual Forum & Technology Display 5
Test aircraft state data
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Test aircraft state data
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Test aircraft state data
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Instrumentation layout
Mobile Acoustics Facility (MAF) Phased array Flight path Snapshot array <1 m max elevation change over array ~900 m st Overview of a Comprehensive MD530F Acoustic Flight Test VFS 81 Annual Forum & Technology Display 9
Weather instrumentation
LiDAR vertical wind profilers Mean wind profile per sortie Calmest sortie Windiest sortie Wind Speed (knots) st Overview of a Comprehensive MD530F Acoustic Flight Test VFS 81 Annual Forum & Technology Display 10
Weather instrumentation
Flyover 1 Flyover 2 Flyover 3 Temperature string st Overview of a Comprehensive MD530F Acoustic Flight Test VFS 81 Annual Forum & Technology Display 11
Ground weather instrumentation
Contours: atmospheric attenuation at 1 kHz 60 m propagation 450 m propagation dB dB 06:00 Ground weather stations 09:00 12:00 Temperature (deg. C) Temperature (deg. C) st Overview of a Comprehensive MD530F Acoustic Flight Test VFS 81 Annual Forum & Technology Display 12
Pilot ground guidance systems
Repurposed Runway Indicator End Lights st Overview of a Comprehensive MD530F Acoustic Flight Test VFS 81 Annual Forum & Technology Display 13
Pilot ground guidance systems
High - visibility banners Repurposed Runway Indicator End Lights st Overview of a Comprehensive MD530F Acoustic Flight Test VFS 81 Annual Forum & Technology Display 14
Pilot ground guidance systems
Precision Approach Path Indicators (PAPI) High - visibility banners Repurposed Runway Indicator End Lights st Overview of a Comprehensive MD530F Acoustic Flight Test VFS 81 Annual Forum & Technology Display 15
Instrumentation layout - snapshot array
Snapshot array center Flight path Snapshot array outskirts ~900 m st Overview of a Comprehensive MD530F Acoustic Flight Test VFS 81 Annual Forum & Technology Display 16
Snapshot array
Nose dB horizon Port Starboard 90 kt, 60 m altitude level flyover under 4 runs Tail Tail vehicle st Overview of a Comprehensive MD530F Acoustic Flight Test VFS 81 Annual Forum & Technology Display 17
Snapshot array
Nose horizon Starboard Port Error (dB) sqrt(MSE) [dB] under Tail Tail vehicle Microphone density Microphones within Region of Interpolation (r = 3 Snapshot array design details in: Objective Understand array design Houston et al., “ Snapshot Array Design considerations, i.e., the Considerations for Rotorcraft Noise effect of channel count Characterization ,” VFS 81, 2025 .
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Design of experiments approach
Standard approach Combined design DoE analysis in: Stephenson, J., Pascioni, K., “ Design of Experiments Development for Rotorcraft Acoustic Flight Testing ,” VFS 81, 2025 Objective To mature flight test planning tools and increase flight test efficiency st Overview of a Comprehensive MD530F Acoustic Flight Test VFS 81 Annual Forum & Technology Display 19
Maneuvers
Maneuver noise analysis in: Acoustic Assessment of an Stutz et al., “ MD530F Helicopter in Maneuvering Flight ” VFS 81, 2025 Objective Determine appropriate methods to investigate unsteady flight st Overview of a Comprehensive MD530F Acoustic Flight Test VFS 81 Annual Forum & Technology Display 20
Maneuvers
Maneuver noise analysis in: Acoustic Assessment of an Stutz et al., “ MD530F Helicopter in Maneuvering Flight ” VFS 81, 2025 Objective Determine appropriate methods
Frozen!
to investigate unsteady flight st Overview of a Comprehensive MD530F Acoustic Flight Test VFS 81 Annual Forum & Technology Display 21
90 - knot level flight – snapshot array
OASPL [dB] Raw - total Vold - Kalman filtered - main rotor Time [ ms ] Time [ ms ] st Overview of a Comprehensive MD530F Acoustic Flight Test VFS 81 Annual Forum & Technology Display 22
90 - knot level flight – VKF extracted
OASPL [dB] Main Rotor VKF Hemisphere Original Hemisphere st Overview of a Comprehensive MD530F Acoustic Flight Test VFS 81 Annual Forum & Technology Display 23
Instrumentation layout - FLT 201 phased array
Flight path Phased array (aircraft perspective) st Overview of a Comprehensive MD530F Acoustic Flight Test VFS 81 Annual Forum & Technology Display 24
Instrumentation layout - FLT 209 phased array
Flight path Phased array (aircraft perspective) st Overview of a Comprehensive MD530F Acoustic Flight Test VFS 81 Annual Forum & Technology Display 25
Phased array results
• Rotating Source Identifier (ROSI) by Sijtsma [1] • Scan grid rotation synchronized with main rotor • 20 kt forward flight (40 rotor revolutions) 2 kHz 1/3 - octave Array shading techniques applied Used Phased array analysis in: Pascioni et al., “ Phased Array Measurements of a Full - Scale Helicopter, ” VFS 81, 2025 Not used Objective Assess feasibility of rotating beamforming algorithms to separate nondeterministic noise, per propulsor Sijtsma, Oerlemans, & Holthusen, AIAA 2001 - 2167.
st Overview of a Comprehensive MD530F Acoustic Flight Test VFS 81 Annual Forum & Technology Display 26 This work was supported by the the U.S. Army, Combat Capabilities Development Command Aviation & Missile Center, and the NASA Aeronautics Research Mission Directorate, Revolutionary Vertical Lift Technology Project.
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