Engineering topics

Young, Larry A.

Publications and source records attributed to Young, Larry A..

At least 19 records

NASA NTRS2020

Motivations and Preliminary Design for Mid-Air Deployment of a Science Rotorcraft on Mars

Mid-Air Deployment (MAD) of a rotorcraft during Entry, Descent and Landing (EDL) on Mars eliminates the need to carry a propulsion or airbag landing system. This reduces the total mass inside the aeroshell by more than 100 kg, aeroshell complexity, and likely the risk and cost associated to the mission. Moreover, the lighter entry mass enables landing in the Martian highlands, at elevations inaccessible to current EDL technologies. This paper proposes a novel MAD concept for a Mars helicopter. We suggest a minimum science payload package to perform relevant science in the highlands. A variant of the Ingenuity helicopter is proposed to provide increased deceleration during MAD, and enough lift to fly the science payload in the highlands. We show in simulation that the lighter aeroshell results in lower terminal velocity (30 m/s) at the end of the parachute phase of the EDL, and at higher altitudes than other approaches. After discussing the aerodynamics, controls, guidance and mechanical challenges associated to deploying at such speed, we propose a backshell architecture that addresses them to release the helicopter in the safest conditions. Finally, we implemented the helicopter model and aerodynamic descent perturbations in the JPL Dynamics and Real-Time Simulation (DARTS) framework. Preliminary performance evaluation indicate landing and helicopter operations can be achieved up to +5 km MOLA.

Rapin, William↗

NASA NTRS2020

Accessibility Design and Operational Considerations in the Development of Urban Aerial Mobility Vehicles and Networks

Urban aerial mobility vehicles and networks have recently gained considerable interest in the aviation community. These small, short-range vehicles with all-electric or hybrid-electric propulsion systems, tailored to metropolitan aerial transportation needs, promise to radically change passenger mobility and cargo distribution in cities. Accessibility issues have not been a major consideration in UAM vehicle and network discussions to date. This paper seeks to help change that.

Young, Larry A.↗

NASA NTRS2018

What is a Tiltrotor? A Fundamental Reexamination of the Tiltrotor Aircraft Design Space

The objective of this work is to fundamentally reexamine the design space of tiltrotor aircraft beyond the very successful conventional vehicle configuration with tractor-type twin proprotors that are nacelle-mounted at the wing tips. Previously proposed alternate tiltrotor configurations include the Bell quad-tiltrotor and the Augusta Westland ERICA hybrid tiltrotor/tiltwing concepts. More recently, arguably alternate tiltrotor configurations include the NASA Langley "Puffin" and the Joby Aviation S-2 concepts. This work seeks to define a broad aircraft design space for alternate tiltrotor configurations. Being doing so, it is hoped this work will not only provide design inspiration for future aircraft developers but to also help realize new applications and missions for both passenger-carrying vehicles and vertical lift UAVs (Unmanned Aerial Vehicles) might one day be successfully enabled.

Reexamination↗

NASA NTRS2017

System-of-Systems Considerations in the Notional Development of a Metropolitan Aerial Transportation System

There are substantial future challenges related to sustaining and improving efficient, cost-effective, and environmentally friendly transportation options for urban regions. Over the past several decades there has been a worldwide trend towards increasing urbanization of society. Accompanying this urbanization are increasing surface transportation infrastructure costs and, despite public infrastructure investments, increasing surface transportation "gridlock." In addition to this global urbanization trend, there has been a substantial increase in concern regarding energy sustainability, fossil fuel emissions, and the potential implications of global climate change. A recently completed study investigated the feasibility of an aviation solution for future urban transportation (refs. 1, 2). Such an aerial transportation system could ideally address some of the above noted concerns related to urbanization, transportation gridlock, and fossil fuel emissions (ref. 3). A metro/regional aerial transportation system could also provide enhanced transportation flexibility to accommodate extraordinary events such as surface (rail/road) transportation network disruptions and emergency/disaster relief responses.

Alonso, Juan J.↗

NASA NTRS2016

Documentation of the Recirculation in a Closed-Chamber Rotor Hover Test

A rotor hover test was performed inside the JPL 25-foot-diameter Space Simulator. The 40-inch-diameter rotor was tested at two locations in the chamber-on the chamber centerline and 2m off-axis. The rotor was tested in both upright and inverted configurations for 500 < RPM < 2000. Fluorescent tufts were used to identify regions of recirculation. Velocities on the entrainment side of the rotor were measured. Tabulated values for the mean entrainment velocity components and the corresponding root mean square velocity fluctuations are provided. Unsteady velocity measurements provide a description of the turbulence ingested into the rotor plane and quantify the unsteady velocity field that the Mars Scout Helicopter can expect to encounter during free flight inside the Space Simulator.

Rotor Hover Test↗

NASA NTRS2015

Simulated Tiltrotor Aircraft Operation in Close Proximity to a Building in Wind and Ground-Effect Conditions

A mid-fidelity computational fluid dynamics tool called RotCFD specifically developed to aid in rotorcraft studies has been applied to the study of wake interactions of civiltiltrotor aircraft in the immediate vicinity of buildings, in- and out-of-ground-effect, with and without winds, consistent with notional tiltrotor operations from urban vertiports. Such civil tiltrotor operations from urban vertiports could potentially enable city-center-to-city center commercial transport. However, in order to one day realize such civil tiltrotor operations, though, it is necessary to better understand the wake interaction and interactional aerodynamic operating environment of urban vertiports. In the early 2000s, a series of 7-by-10 Ft. wind tunnel tests were conducted at NASA Ames Research Center that began to explore some of these civil tiltrotor and vertiport wake interactioninteractional aerodynamics issues. This study seeks to validate computation fluid dynamic predictions against these early wind tunnel experimental results and, thereby, continue exploration of this important research area.

Rotorcraft↗

NASA NTRS2015

Conceptual Design Aspects of Three General Sub-Classes of Multi-Rotor Configurations: Distributed, Modular, and Heterogeneous

Quadcopters and other multi-rotor configurations are poised to make a substantial contribution to commercial and public service aviation. Small multi-rotor configurations already see almost ubiquitous use as radio-controlled toys and hobbyist platforms. In particular, their use as flying cameras has seen rapid adoption by the public. But their greatest contribution to our society may likely be seen in public service missionsapplications. Their potential utility for supporting emergency response missions is discussed in some detail. The multi-rotor design space is then explored from high-level perspective with the emphasis on distributed, modular, and heterogeneous multi-rotor systems. Following this design space examination, a number of specific, detailed technical issues related multi-rotor conceptual design and sizing is also considered.

Configurations↗

NASA NTRS2013

Simulated Rotor Wake Interactions Resulting from Civil Tiltrotor Aircraft Operations Near Vertiport Terminals

A mid-fidelity computational fluid dynamics tool called RotCFD - specifically developed to aid in rotorcraft conceptual design efforts - has been applied to the study of rotor wake interactions of civil tiltrotor aircraft in the immediate vicinity of vertiport/airport ground infrastructure. This issue has grown in importance as previous NASA studies have suggested that civil tiltrotor aircraft can potentially have a significant impact on commercial transport aviation. Current NASA reference designs for such civil tiltrotor aircraft are focused on a size category of 90-120 passengers. Notional concepts of operations include simultaneous non-interfering flight into and out of congested airports having vertiports, that is, prepared VTOL takeoff and landing zones, or underutilized short runways for STOL operation. Such large gross-weight vehicles will be generating very high induced velocities. Inevitably, the interaction of the rotor wake with ground infrastructure such as terminals/jetways must be considered both from an operational as well as design perspective.

Young, Larry A.↗

NASA NTRS2011

Rotary Wing Deceleration Use on Titan

Rotary wing decelerator (RWD) systems were compared against other methods of atmospheric deceleration and were determined to show significant potential for application to a system requiring controlled descent, low-velocity landing, and atmospheric research capability on Titan. Design space exploration and down-selection results in a system with a single rotor utilizing cyclic pitch control. Models were developed for selection of a RWD descent system for use on Titan and to determine the relationships between the key design parameters of such a system and the time of descent. The possibility of extracting power from the system during descent was also investigated.

Young, Larry A.↗

NASA NTRS2010

Rotorcraft and Enabling Robotic Rescue

This paper examines some of the issues underlying potential robotic rescue devices (RRD) in the context where autonomous or manned rotorcraft deployment of such robotic systems is a crucial attribute for their success in supporting future disaster relief and emergency response (DRER) missions. As a part of this discussion, work related to proof-of-concept prototyping of two notional RRD systems is summarized.

Young, Larry A.↗

NASA NTRS2010

Overview of the Novel Intelligent JAXA Active Rotor Program

The Novel Intelligent JAXA Active Rotor (NINJA Rotor) program is a cooperative effort between JAXA and NASA, involving a test of a JAXA pressure-instrumented, active-flap rotor in the 40- by 80-Foot Wind Tunnel at Ames Research Center. The objectives of the program are to obtain an experimental database of a rotor with active flaps and blade pressure instrumentation, and to use that data to develop analyses to predict the aerodynamic and aeroacoustic performance of rotors with active flaps. An overview of the program is presented, including a description of the rotor and preliminary pretest calculations.

Saito, Shigeru↗

NASA NTRS2010

Preliminary Investigation of Civil Tiltrotor in NextGen Airspace

Presentation intro: Tiltrotor aircraft have long been envisioned as being a potentially viable means of commercial aviation transport. Preliminary results from an ongoing study into the operational and technological considerations of Civil Tiltrotor (CTR) operation in the Next Generation airspace, circa the 2025 time-frame, are presented and discussed. In particular, a fleet of CTR aircraft has been conceptually designed. The performance characteristics of this CTR fleet was subsequently translated into BADA (Base of Aircraft DAta) models that could be used as input to emulate CTR aircraft operations in the ACES and AvTerminal airspace and terminal area simulation tools. A network of nine North-Eastern corridor airports is the focus of the airspace simulation effort; the results from this airport network viII then be extrapolated to provide insights into systemic impact of CTRs on the National Airspace System (NAS). Future work will also be detailed as to attempts to model the systemic effects of noise and emissions from this fleet of new aircraft as well as assess their leveraged impact on public service missions, in time of need, such as major regional/national disaster relief efforts. The ideal outcome of this study is a set of results whereby Next Gen airspace CONOPs can be refined to reflect potential CTR capabilities and, conversely, CTR technology development efforts can be better informed as to key performance requirement thresholds needed to be met in order to successfully introduce these aircraft into civilian aviation operation.

Young, Larry A.↗

NASA NTRS2009

NASA Subsonic Rotary Wing Project

This slide presentation will outline the rationale for, and the initial results of, a contractor study being performed by a SAIC-led team of Bell Helicopter Textron, Sensis, and Optimal Synthesis. Together, this team represents an extensive body of subject matter expertise as related to rotorcraft technologies and design, airspace demand modeling simulation, and terminal area operations and flight path planning. The initial conceptual design results of a fleet of civil tiltrotor aircraft ranging in size from 10 to 120 passengers is a key highlight of the work to be presented. The intent of this presentation is to begin to provide the general community of rotorcraft researchers, manufacturers, and end-users an appreciation of the criticality of interjecting rotorcraft-specific technology and concepts of operation issues into Next Gen airspace requirements

Young, Larry A.↗

NASA NTRS2009

A Status of NASA Rotorcraft Research

In 2006, NASA rotorcraft research was refocused to emphasize high-fidelity “first-principles” predictive tool development and validation. As part of this new emphasis, documenting the status of NASA rotorcraft research and defining the state-of-the-art in rotorcraft predictive capability were undertaken. This report is the result of this two-year effort. Contributors to this work encompass a wide range of expertise covering the technical disciplines of aeromechanics, acoustics, computational fluid dynamics (CFD), flight dynamics and control, experimental capabilities, propulsion, structures and materials, and multi-disciplinary analysis.

Rotorcraft Research↗

NASA NTRS2008

Systems Engineering: When Knowledge and Technology are the Product

The interdependence of technology development, conceptual design, and system analysis is examined in the context of an overall systems engineering set of processes. In particular, the role of technology portfolio management - from initial investment decision-making all the way through technology maturation and transfer to industry - is emphasized. Additionally, the role of state of the art assessments is considered in terms of planning and tracking progress towards the development of enhanced predictive capabilities.

Young, Larry A.↗

NASA NTRS2007

A Family of Vortices to Study Axisymmetric Vortex Breakdown and Reconnection

A new analytic model describing a family of vortices has been developed to study some of the axisymmetric vortex breakdown and reconnection fluid dynamic processes underlying body-vortex interactions that are frequently manifested in rotorcraft and propeller-driven fixed-wing aircraft wakes. The family of vortices incorporates a wide range of prescribed initial vorticity distributions -- including single or dual-core vorticity distributions. The result is analytical solutions for the vorticity and velocities for each member of the family of vortices. This model is of sufficient generality to further illustrate the dependence of vortex reconnection and breakdown on initial vorticity distribution as was suggested by earlier analytical work. This family of vortices, though laminar in nature, is anticipated to provide valuable insight into the vortical evolution of large-scale rotor and propeller wakes.

Young, Larry A.↗

NASA NTRS2007

Enhanced Rescue Lift Capability

The evolving and ever-increasing demands of emergency response and disaster relief support provided by rotorcraft dictate, among other things, the development of enhanced rescue lift capability for these platforms. This preliminary analysis is first-order in nature but provides considerable insight into some of the challenges inherent in trying to effect rescue using a unique form of robotic rescue device deployed and operated from rotary-wing aerial platforms.

Young, Larry A.↗

NASA NTRS2007

Feasibility of Turing-Style Tests for Autonomous Aerial Vehicle "Intelligence"

A new approach is suggested to define and evaluate key metrics as to autonomous aerial vehicle performance. This approach entails the conceptual definition of a "Turing Test" for UAVs. Such a "UAV Turing test" would be conducted by means of mission simulations and/or tailored flight demonstrations of vehicles under the guidance of their autonomous system software. These autonomous vehicle mission simulations and flight demonstrations would also have to be benchmarked against missions "flown" with pilots/human-operators in the loop. In turn, scoring criteria for such testing could be based upon both quantitative mission success metrics (unique to each mission) and by turning to analog "handling quality" metrics similar to the well-known Cooper-Harper pilot ratings used for manned aircraft. Autonomous aerial vehicles would be considered to have successfully passed this "UAV Turing Test" if the aggregate mission success metrics and handling qualities for the autonomous aerial vehicle matched or exceeded the equivalent metrics for missions conducted with pilots/human-operators in the loop. Alternatively, an independent, knowledgeable observer could provide the "UAV Turing Test" ratings of whether a vehicle is autonomous or "piloted." This observer ideally would, in the more sophisticated mission simulations, also have the enhanced capability of being able to override the scripted mission scenario and instigate failure modes and change of flight profile/plans. If a majority of mission tasks are rated as "piloted" by the observer, when in reality the vehicle/simulation is fully- or semi- autonomously controlled, then the vehicle/simulation "passes" the "UAV Turing Test." In this regards, this second "UAV Turing Test" approach is more consistent with Turing s original "imitation game" proposal. The overall feasibility, and important considerations and limitations, of such an approach for judging/evaluating autonomous aerial vehicle "intelligence" will be discussed from a theoretical perspective.

Young, Larry A.↗