Browse Topic: Fairings

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Computational Analyses of Coaxial Rotor Hub Flows and Correlation with ExperimentF-0081-2025-02495/20/2025
This study presents computational analyses of coaxial rotor hub flows and validation against experimental data obtained from the fifth Rotor Hub Flow Prediction Workshop. Experiments were conducted in a 12-inch diameter water tunnel at Pennsylvania State Applied Research Laboratory, employing tomographic particle-image velocimetry (Tomo-PIV) and precise hub drag measurements. Three CFD codes (UMD Mercury, CREATETM-AV Helios, and OVERFLOW) utilizing hybrid Reynolds-Averaged Navier-Stokes (RANS) / Large Eddy Simulation (LES) modeling based on Spalart–Allmaras turbulence model, were applied to replicate and analyze hub flows. Counter-rotating coaxial rotor hubs under free-air condition was simulated as the simplest case and the hub drags are compared between the three CFD codes. The full water tunnel configuration, consisting of two hubs, a fairing, and shafts, was also simulated and compared to experimental results, with a focus on hub drag, wake velocity fields, and turbulence
Jung, Yong Su, Baeder, James, Premaratne, Pavithra, Jain, Rohit, Deore, Neal, Coder, James, Schmitz, Sven, Gosin, Samuel
Computational Analysis of Behavior and Structures of Coaxial Rotor Hub and Sail Fairing WakeF-0080-2024-13125/7/2024
A computational study is conducted on a coaxial rotor hub and sail fairing configuration to analyze hub surface forces and the characteristics of its downstream wake. The flow conditions and grids are based on experimental tests performed at the Penn State Applied Research Lab (ARL) Water Tunnel at a baseline Reynolds number. Grid development for the rotor hubs and sail fairing is done using Pointwise v18.04R1 and Chimera Grid Tools (version 2.2). Simulations are performed using NASA's OVERFLOW2.4b Reynolds Averaged Navier-Stokes solver. The drag forces on the rotor hubs are computed and compared to standalone drag data to analyze the effects of interactional aerodynamics. Flow features, frequency content and Reynolds stresses of the wake are analyzed. Frequency content and Reynolds stresses show clear spatial bias. The anisotropy of the Reynolds stresses is computed and used to determine the character of the wake turbulence.
Deore, Neal, Coder, James
Computational Analysis of Coaxial Rotor Hub and Sail Fairing WakeF-0079-2023-179945/16/2023
ABSTRACT
Deore, Neal, Mobley, Forrest, Coder, James
An Overview Of DLR Compound Rotorcraft Aerodynamics and Aeroacoustics Activities within the CleanSky2 NACOR ProjectF-0074-2018-127275/14/2018
ABSTRACT The challenge of increasing range and speed of a rotorcraft is encountered in the scope of the European CleanSky2 "Fast Rotorcraft" project by Airbus Helicopters with the compound helicopter design RACER (RapidAndCostEfficientRotorcraft) for which the box wing and the tail parts designs are respectively protected by patent. This paper presents the DLR contributions to the RACER development. This includes the aerodynamic design of the wing and tail section as well as an overall assessment of performance and noise. In a first step the aerodynamic properties of the configuration are evaluated both isolated and with consideration of the main rotor and lateral rotor interferences by the use of actuator discs. In the second step, the investigated possibilities to improve the configurations performance are described. These include airfoil design for improved high lift performance of the wing and tail section, an optimization of the box wing circulation distribution on the upper and
Wentrup, Marc, Pinacho, Jean-Paul, Yin, Jianping, Kunze, Philipp, Streit, Thomas, Wendisch, Jan-Hendrik, Schwarz, Thorsten, Kicker, Klaus, Fukari, Raphël
Dual-Use Structures: Composite Wing with Structural Antenna ApertureF-0072-2016-115525/17/2016
Many modern aircraft, including rotorcraft, require conformal antennas and fairings to reduce wind drag, ice accretion, lightning strikes, and impact damage. An innovative composite wing configuration with a structural Ultra High Frequency (UHF) antenna window "aperture" has been developed. The wing is based on variants of lightweight X-Cor® sandwich core technology for durability and damage tolerance, with tailored electromagnetic properties in the aperture region of the wing. This paper presents a brief introduction to helicopter wings, a summary of recent research at Boeing and Army leading to this design, and the development approach used for this project. Structural and electromagnetic analyses are provided, and measurement results of an early prototype are summarized. The emphasis of this paper is on the wing configuration details surrounding the antenna aperture. The approach can be replicated on almost any current or future aircraft or rotorcraft.
Tyrell, Stacey, Robeson, Mark, Kube, Courtney, McCarthy, Dennis, Lavin, Ronald
Experimental Investigation of Passive and Active Flow Control for X2 Technology Hub and Fuselage Drag ReductionF-0072-2016-113795/17/2016
The effects of passive, active, and combined flow control on the aerodynamic performance of an unpowered, bladeless 1/5th scale model of the X2 Technology™ Demonstrator have been assessed through a variety of surface and off-body measurements in a low-speed wind tunnel test, Re = 88x10³ [1/ft] and M∞ = 0.13. The baseline model employs a state-of-the-art low-drag coaxial hub design. Further drag reduction was investigated through minor design alterations, endplates, vortex generators, steady blowing and suction, and oscillatory blowing. Each drag mitigation control approach was individually assessed. Flow control technologies that produced the most promising test results were combined for further augmented performance. Six-component external balance loads, independent hub and tail loads, and surface and wake flow and pressure measurements were used to determine aerodynamic performance and the detailed physics of the flow control attributes. The wind tunnel test showed that the addition
Bowles, Patrick, Geiger, Derek, Thomas, Mathew, Botros, Barbara, Matalanis, Claude, Min, Byung-Young, Wake, Brian
Overview of S-97 RAIDER Scale Model TestsF-0072-2016-115595/17/2016
A sequence of scale model wind tunnel tests have been conducted to help design the S-97 RAIDER™ aircraft and better understand the aerodynamics of X2 Technology™ rotorcraft incorporating coaxial rigid lift offset rotors, low drag airframes, and a pusher propeller. The tests provided inputs to aerodynamics and flight dynamics simulations, validation data for CFD, and aerodynamic loads for design. The first test obtained high Reynolds number aerodynamic coefficients for airfoil families planned for the main rotor blades. A particular focus was on forward and reverse flow data for a thick single ended airfoil and a double-ended airfoil. A 1/10 scale unpowered airframe was then tested in the UTRC Pilot Wind Tunnel to obtain basic aerodynamic loads, plus flow interaction diagnostics on the fuselage, tail, and at the propeller plane. A hub and sail fairing drag test was conducted to obtain quantitative drag measurements on multiple fairing geometries, and to get insight into the effect of
Lorber, Peter, Matalanis, Claude, Law, Gary, O'Neill, John, Bowles, Patrick
Ascent Heating Thermal Analysis on Spacecraft Adaptor FairingsTBMG-98935/1/2011
When the Crew Exploration Vehicle (CEV) is launched, the spacecraft adaptor (SA) fairings that cover the CEV service module (SM) are exposed to aero heating. Thermal analysis is performed to compute the fairing temperatures and to investigate whether the temperatures are within the material limits for nominal ascent aero-heating case. The ascent heating is analyzed by using computational fluid dynamics (CFD) and engineering codes at Marshall Space Flight Center. The aero-heating environment data used for this work is known as Thermal Environment 3 (TE3) heating data. One of the major concerns is with the SA fairings covering the CEV SM and the SM/crew launch vehicle (CLV) flange interface. The TE3 heating rate is a function of time, wall temperature, and the spatial locations. The implementation of the TE3 heating rate as boundary conditions in the thermal analysis becomes challenging.
Noise-Reducing Fairings for Flush-Mounted MicrophonesTBMG-299533/1/1999
Streamlined fairings have been invented for housing single or multiple microphones to measure noise in flowing gases and liquids. Each fairing of this type is designed to minimize the spurious (background) component of noise generated by local flow disturbances caused by the fairing itself. These fairings could be used in measuring noise associated with a variety of flow sources, including aircraft, wind tunnels, air-handling equipment, and land vehicles.
High-Wind Masts for Meteorological InstrumentsTBMG-320912/1/1998
Rigid, guyed masts of a proposed type for supporting meteorological instruments would be designed to withstand considerably stronger winds than those conventionally used. The proposed fairings would also help minimize perturbations of airflows and thereby minimize the contaminating effects of the masts on measurements taken by instruments mounted on the masts.
Synthetic Rubber Low-Temperature Resistant, 45-55AMS3205J (Historical)1/1/1993
This specification covers a synthetic rubber in the form of sheet, strip, tubing, molded shapes, and extrusions. These products have been used typically for parts, such as sleeves, fairings, grommets, and window channels, where resistance to low temperature is of prime importance, but usage is not limited to such applications. Each application, however, should be considered individually.
AMS CE Elastomers Committee
Synthetic Rubber Low-Temperature Resistant, 45-55AMS3205H (Historical)4/1/1984
This specification covers a synthetic rubber in the form of sheet, strip, tubing, molded shapes, and extrusions. These products have been used typically for parts, such as sleeves, fairings, grommets, and window channels, where resistance to low temperature is of prime importance, but usage is not limited to such applications. Each application, however, should be considered individually.
AMS CE Elastomers Committee
Synthetic Rubber Low-Temperature Resistant, 45-55AMS3205G (Historical)7/1/1977
This specification covers a synthetic rubber in the form of sheet, strip, tubing, molded shapes, and extrusions. These products have been used typically for parts, such as sleeves, fairings, grommets, and window channels, where resistance to low temperature is of prime importance, but usage is not limited to such applications. Each application, however, should be considered individually.
AMS CE Elastomers Committee
Synthetic Rubber Low-Temperature Resistant, 45-55AMS3205F (Historical)7/1/1976
This specification covers a synthetic rubber in the form of sheet, strip, tubing, molded shapes, and extrusions. These products have been used typically for parts, such as sleeves, fairings, grommets, and window channels, where resistance to low temperature is of prime importance, but usage is not limited to such applications. Each application, however, should be considered individually.
AMS CE Elastomers Committee
Synthetic Rubber Low-Temperature Resistant, 45-55AMS3205E (Historical)2/1/1965
This specification covers a synthetic rubber in the form of sheet, strip, tubing, molded shapes, and extrusions. These products have been used typically for parts, such as sleeves, fairings, grommets, and window channels, where resistance to low temperature is of prime importance, but usage is not limited to such applications. Each application, however, should be considered individually.
AMS CE Elastomers Committee
Synthetic Rubber Low-Temperature Resistant, 45-55AMS3205D (Historical)7/1/1956
This specification covers a synthetic rubber in the form of sheet, strip, tubing, molded shapes, and extrusions. These products have been used typically for parts, such as sleeves, fairings, grommets, and window channels, where resistance to low temperature is of prime importance, but usage is not limited to such applications. Each application, however, should be considered individually.
AMS CE Elastomers Committee
Synthetic Rubber Low-Temperature Resistant, 45-55AMS3205C (Historical)6/1/1952
This specification covers a synthetic rubber in the form of sheet, strip, tubing, molded shapes, and extrusions. These products have been used typically for parts, such as sleeves, fairings, grommets, and window channels, where resistance to low temperature is of prime importance, but usage is not limited to such applications. Each application, however, should be considered individually.
AMS CE Elastomers Committee
Synthetic Rubber Low-Temperature Resistant, 45-55AMS3205A (Historical)10/1/1946
This specification covers a synthetic rubber in the form of sheet, strip, tubing, molded shapes, and extrusions. These products have been used typically for parts, such as sleeves, fairings, grommets, and window channels, where resistance to low temperature is of prime importance, but usage is not limited to such applications. Each application, however, should be considered individually.
AMS CE Elastomers Committee
Synthetic Rubber Low-Temperature Resistant, 45-55AMS3205B (Historical)10/1/1945
This specification covers a synthetic rubber in the form of sheet, strip, tubing, molded shapes, and extrusions. These products have been used typically for parts, such as sleeves, fairings, grommets, and window channels, where resistance to low temperature is of prime importance, but usage is not limited to such applications. Each application, however, should be considered individually.
AMS CE Elastomers Committee
Rubber, Synthetic Low-Temperature Resistant, 25-35AMS3204 (Historical)12/1/1942
This specification covers a synthetic rubber in the form of sheet, strip, tubing, molded shapes, and extrusions. Primarily for parts, such as sleeves, fairings, grommets, and window channels, where resistance to low temperature is of prime importance.
AMS CE Elastomers Committee
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