Hierarchical Flexible Toolset for Generating Airfoil Performance Tables for Aircraft Design

Despite the capabilities and usability improvements of modern computational fluid dynamics software, rotary-wing aircraft design and analysis often uses lower fidelity methods that require pre-computed 2D airfoil data tables because these methods can provide adequate accuracy in a fraction of the setup and computation time. The C81 data format has long been used by rotorcraft sizing, conceptual, and preliminary design tools to define airfoil lift, drag and moment as a function of angle of attack, Mach number, and Reynolds number. Even though C81 tables have a long legacy of use, their generation, especially for new airfoil sections typical of modern Urban Air Mobility configurations, is far from routine given the need to cover 360o angle of attack over a range of Mach and Reynolds numbers – with manual tuning often used to fill-in missing data or remove questionable points. The proposed effort by Continuum Dynamics, Inc., (CDI), seeks to build upon our decades of experience developing and using C81 tables for rotorcraft design and analysis to develop a software toolset tailored to automatically and robustly generating accurate and reliable C81 tables. The toolset will feature a range of methods for automatically predicting single and multi-element airfoil section performance, and assembling the resulting C81 tables. In Phase I, a prototype tool with automatic grid generation, will be developed that launches, monitors, and post-processes airfoil performance predictions. The tool will then assemble the desired C81 table from the database of predictions and experimental data, and provide uncertainty metrics to the user associated with the source of the data used. The tool will be built around CDI’s in-house 2D CFD solver that we use to generate 2D look-up tables, but within a framework flexible enough to support alternate CFD solvers. Phase II will see software enhancement and generalization to support a variety of data and prediction generation sources. Urban Air Mobility aircraft and rotorcraft sizing, design, and analysis tools often rely on airfoil data tables (e.g. C81 tables). While C81 tables have a long legacy of use, their generation is far from routine given the need to cover 360o angle of attack over a range of Mach and Reynolds numbers. Continuum Dynamics, Inc. (CDI) proposes to build upon our decades of experience creating and using C81 tables to develop a tool (AirfoilGen) for automatically and robustly generating accurate and reliable C81 tables. AirfoilGen will feature a range of methods for automatically predicting single and multi-element airfoil performance, assembling the resulting C81 tables, and providing the user with uncertainly metrics associated with the source of the data used. Phase I will develop a prototype tool that launches, monitors, and post-processes airfoil performance predictions, and assembles the C81 table from the database of predictions and experimental data. Phase II will see software enhancement and generalization to support a variety of data and prediction generation sources.

NASA is actively involved in investigating Vertical Takeoff and Landing (VTOL) Urban Air Mobility (UAM) aircraft aeromechanics, flying and handling qualities, and acoustics, and thus the proposed software tool suite would be of immediate use to NASA engineers. The proposed effort directly supports the Aeronautics Research Mission Directorate’s (ARMD’s) Strategic Implementation Plan’s Strategic Thrust 4: Safe, Quiet, and Affordable Vertical Lift Air Vehicles, as well as ARMD’s Revolutionary Vertical Lift Technology (RVLT) Project under the Advanced Air Vehicle Program. The RVLT project is developing and validating tools that address the limitations of current software tools for designing and analyzing VTOL vehicles for use on Earth as well as missions to Mars and other planets. Given the synergy between the RVLT project and the proposed effort, it is currently anticipated that this would be the first direct NASA application of the C81 table generation toolset. Recently, NASA has been aggressively performing wind tunnel testing of single and installed rotary-wing and fixed-wing system components to support the exploding field of eVTOL and UAM aircraft vehicle concept development. Each of these tests has a parallel modeling and simulation component requiring the generation of 2D look-up tables to model the airfoils on the tested components as needed by NASA’s modeling software. The proposed effort directly supports this by providing NASA a uniform, robust method for generating these necessary tables. Urban Air Mobility (UAM – though often used interchangeably with Advanced Air Mobility (AAM)) aircraft are revolutionizing the aerospace industry, and numerous concepts are in development. Given the geometric complexity and unconventional nature of UAM concepts, which often have multiple rotors, propellers, and wings, lower-fidelity design and analysis tools that use pre-defined airfoil performance look-up tables are often used because they keep the cost of computation manageable. Generating these pre-defined airfoil performance tables is a labor intensive process that often requires manual expert engineering intervention to ensure reliable results. This effort seeks to address exactly this issue by developing a software toolset for automatically generating accurate and reliable C81 tables. This software fills a critical technical need for industry and government, and we anticipate significant commercialization by licensing it to engineers involved in rotary-wing aircraft design, flight testing, operations, simulation, and support. Despite some recent setbacks, the UAM market continues to flourish thanks to diversification into military and freight applications. In 2023 the total market was $9.77B, and it is expected to exceed $100B by 2032. According to the Vertical Flight Society, there are over a thousand vehicles in development, with the most viable manufacturers tracked by SMG Consulting’s AAM Reality Index. As described in more detail in the proposal, CDI has an established business providing engineering design/analysis software and services to the VTOL industry, which has grown in recent years along with the UAM market. Given our current customer base and reputation in the field, we are well positioned to transition the C81 table generation technology to the UAM market as an add-on to existing software, as standalone software, or as a service where we use the software in-house to generate the tables.

This is a mature technology (TRL 7+) — the realistic path in is usually NASA's Technology Transfer Program: licensing an existing NASA patent, or a Space Act Agreement to use NASA facilities/expertise directly. NASA also runs a startup licensing program with no upfront fee for companies formed to commercialize a specific NASA technology.

None of these are guaranteed paths for this specific project — TechPort itself doesn't have an "apply" button. Reaching out to the contact(s) above with a specific question is usually the fastest way to find out what's actually open.