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Hampton, VA, United States

Ratvasky T.P.,NASA | Barnhart B.P.,Bihrle Applied Research, Inc. | Lee S.,ASRC Aerospace Corporation
Journal of Aircraft | Year: 2010

Icing alters the shape and surface characteristics of aircraft components, which results in altered aerodynamic forces and moments caused by air flow over those iced components. The typical effects of icing are increased drag, reduced stall angle of attack, and reduced maximum lift. In addition to the performance changes, icing can also affect control surface effectiveness, hinge moments, and damping. These effects result in altered aircraft stability and control and flying qualities. Over the past 80 years, methods have been developed to understand how icing affects performance, stability, and control. Emphasis has been on wind-tunnel testing of two-dimensional subscale airfoils with various ice shapes to understand their effect on the flowfield and ultimately the aerodynamics. This research has led to wind-tunnel testing of subscale complete aircraft models to identify the integrated effects of icing on the aircraft system in terms of performance, stability, and control. Data sets of this nature enable pilot-in-the-loop simulations to be performed for pilot training or engineering evaluation of system failure impacts or control system design. Source

Gingras D.R.,Bihrle Applied Research, Inc.
AIAA Modeling and Simulation Technologies (MST) Conference | Year: 2013

The adverse effects of in-flight icing, on aircraft aerodynamics, are a major cause of accidents in the commercial and general aviation world. To mitigate these incidents and accidents resulting from this problem, mandates are in place to improve pilot training in these dangerous flight conditions. Since flight simulators are extensively used for pilot training at all levels, recommendations have been made to improve flight simulator fidelity in adverse conditions like icing. To meet the requirements for improved fidelity, reliable proven data sources are needed. This paper presents potential data sources and methods for obtaining in-flight icing aerodynamics data, and provides details of a case study of the DH-6 Twin Otter, where data were collected from advanced wind-tunnel tests and implemented in a flight training device and validated with flight data. The validation results showed that the resulting flight model was suitable for the training tasks to be performed using the device. Source

Agency: Department of Defense | Branch: Air Force | Program: SBIR | Phase: Phase II | Award Amount: 705.93K | Year: 2002

"Bihrle Applied Research (BAR) proposes to develop a single, easy-to-use, Windows based software application capable of supporting flying qualities and performance analysis and simulation tasks from the conceptual design phase through to the flight testingphase. This software will integrate non-linear aerodynamic prediction capability, propulsion system modeling tools, and control power allocation and inversion tools together with a non-linear six-degree-of-freedom simulation environment. This softwaresuite will enable engineers to use even a simple sketch of a configuration to obtain a flight model and flight control system to perform classic stability and control analysis and automated flight tests of a conceptual flight vehicle. The use of such anintegrated tool will foster a more holistic approach to advanced vehicle design that will in turn lower the initial investment into candidate concepts and facilitate more efficient engineering processes throughout development."

Agency: Department of Defense | Branch: Air Force | Program: SBIR | Phase: Phase I | Award Amount: 99.97K | Year: 2008

A comprehensive Multi-physics Simulation Tool (MAST) is proposed to address the void in simulation tools that address the specific needs of the MAV engineer. The MAST provides an enhancement to Bihrle’s commercially successful PC-Based simulation environment D-Six by providing a project structure suited to model flapping-wing and rotary-wing flight vehicles. A project wizard will guide the user in the configuration of the project to account for the specific MAV characteristics to be modeled. The Bihrle Phase I effort lays the foundation for a reconfigurable simulation tool to allow engineers and control designer solve critical issues regarding the control flight of MAVs. At the end of Phase I an element-based set of equations of motion will have been implemented as a new project structure in D-Six and demonstrated. Critical issues regarding the modeling of aerodynamics, aeroelastic-effects, and control-law will be identified for further design during a Phase II effort.

Agency: Department of Defense | Branch: Navy | Program: SBIR | Phase: Phase I | Award Amount: 149.78K | Year: 2008

As the military increasingly relies on the militarization of commercial items, the need to assess these items in the military operational environment is key. This is particularly important in the use of commercial transport aircraft, where operational demands greatly differ between civil and military use. The use of simulation is of crucial importance, both as a method to identify operational and engineering performance, as well as familiarizing pilots with the aircraft characteristics. Unfortunately, the reliance on commercially certified training simulations, with their focus on civilian operational training, do not satisfy the assessment and training requirements for a military vehicle. In order to address the modeling deficiencies for transport aircraft, Bihrle Applied Research (BAR) proposes the development of a new “Total Envelope Modeling Application for Transport Aircraft” (TEMATA) program. The TEMATA effort will integrate recently developed modeling methodology with newly developed test and computational approaches to establish a validated modeling process for the development of high fidelity transport aircraft simulations. Further, the effort will investigate and apply novel methods of deploying these enhanced flight models in both engineering and training applications – from desktop simulation and analysis platforms to integrating the models on novel motion based simulation and in flight simulation applications

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