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Electric Vertical Take-Off and Landing (eVTOL) Vehicle Technologies for Weather-Tolerant Operations

Description:

Scope Title:

Electric Vertical Take-Off and Landing (eVTOL) Technologies for Weather-Tolerant Operations

Scope Description:

The expanding urban air mobility (UAM) vehicle industry has generated a significant level of enthusiasm among aviation designers and manufacturers, resulting in numerous vehicle configurations. The majority of the prototype UAM vehicles have more than four rotors or propellers, have electric propulsion, carry two to six passengers, fly like a helicopter for vertical takeoff and landing (VTOL), and will fly relatively close to the ground and in proximity to buildings with many operational cycles per day. There are many technical challenges facing the industry’s development of safe, quiet, reliable, affordable, comfortable, and certifiable UAM vehicles and vehicle operations. This subtopic area in the NASA SBIR solicitation focuses on specific vehicle technologies in each year's solicitation. NASA's interest through this subtopic is to make technology and tool advancements that support the overall vehicle development and establishment of the market. The focus will be in different technology areas each year at component and subsystem level and not at the overall vehicle system level. The scope of this subtopic is on vertical lift technologies that support the safe, quiet, reliable, affordable, comfortable, and certifiable VTOL aircraft.  The current vehicle focus is the VTOL aircraft that would be required for UAM and public good missions. There are many technical challenges facing industry’s development of safe, quiet, reliable, affordable, comfortable, and certifiable UAM vehicles and vehicle operations. One of those challenges is developing aircraft that are capable of safely flying during typical adverse weather conditions, including rain, icing, lightning, high winds, low visibility, and extreme temperatures.

The focus of this subtopic this year is on advanced vehicle technologies that enable UAM operations in various weather conditions. Innovations are being sought to address the technical areas noted in the following text.  Proposals should address these areas, and proposals that are for other vehicle technologies or vehicle concepts are not of interest in this year's solicitation.

  1. Erosion resistance: low-maintenance technologies are being sought that would mitigate erosion effects of rain, dust, and sand on vehicle surfaces, especially the rotor surfaces.
  2. Rotor icing: lightweight, low-power technologies are being sought that would prevent and/or mitigate ice accretion on rotors for the numerous vehicle configurations/orientations of the rotors/propellers, including rotors that are stopped for large segments of the flight envelope. Unpowered technologies such as icephobic materials and coatings that minimize accretion on rotor blades and lifting surfaces are also of interest.
  3. Sensing: technologies are being sought that would measure component degradation resulting from the various weather conditions and indicate if mitigations are needed to reduce in-flight risks. Such sensing might be for ice accretion on rotors or for rotor blade erosion due to rain, airborne particulate matter, etc.

Any technology advancements must also consider minimizing impact to overall vehicle performance such as to power consumption, system mass and volume, and vehicle aerodynamic efficiency in their design.

The application of the requested technologies should be relevant to the NASA Revolutionary Vertical Lift Technology (RVLT) project’s reference concept vehicles [Refs. 2-3], which embody the key vehicle characteristics of the UAM vehicle configurations being designed throughout industry.

Expected TRL or TRL Range at completion of the Project: 2 to 4

Primary Technology Taxonomy:

  • Level 1 15 Flight Vehicle Systems
  • Level 2 15.X Other Flight Vehicle Systems

Desired Deliverables of Phase I and Phase II:

  • Analysis
  • Research
  • Prototype

Desired Deliverables Description:

Phase I of the SBIR should develop design concepts for specific technology advancements supported by analytical studies including modeling and simulation.  Phase I effort should establish Phase II goals and should quantify projections of technology performance.

Phase II of the SBIR should further develop the technology designs and validate achievement of goals through additional analysis, modeling, and simulation and through system/component testing to characterize performance and functionality.  Phase II incorporates experiments with aircraft-relevant hardware available commercially or through partnership with an aircraft component supplier and modified with innovative technology from this SBIR effort.

State of the Art and Critical Gaps:

There are over 200 UAM vehicle concepts in varying stages of development. The immediate focus of the vehicle developers is overcoming obstacles on the path to certification. The public has experience flying in large transport aircraft and regional fixed-wing aircraft and are calibrated to associated safety levels for commercial air transportation. Detailed certification requirements for UAM vehicles are still under development by the relevant certifying authorities. For UAM aircraft, research is needed that addresses safety and reliability expectations of the traveling public and certifying authorities. The market/application of these vehicles will be in urban and rural locations, and be expected to have high use (life) in a broad range of weather conditions. The technologies to enable broadened weather-tolerant operations are needed.

Relevance / Science Traceability:

This subtopic is relevant to the Aeronautics Research Mission Directorate (ARMD) RVLT Project under the Advanced Air Vehicle Program. The goal of the RVLT Project is to develop and validate tools, technologies, and concepts to overcome key barriers for vertical lift vehicles. The project scope encompasses technologies that address noise, speed, mobility, payload, efficiency, environment, and safety for both conventional and nonconventional vertical lift configurations. This subtopic directly aligns with the mission, goals, and scope in addressing the Advanced Air Mobility mission objective of V.6.3 Weather Tolerant Vehicle Technologies (Develop technology concepts for reliable and safe operations of UAM vehicles during weather-related challenges.).

References:

  1. Silva, C., Johnson, W. R., Solis, E., Patterson, M. D., and Antcliff, K. R., “VTOL Urban Air Mobility Concept Vehicles for Technology Development,” 2018 Aviation Technology, Integration, and Operations Conference, American Institute of Aeronautics and Astronautics, 2018. [AIAA 2018-3847]
  2. Johnson, W., Silva, C., and Solis, E., “Concept Vehicles for VTOL Air Taxi Operations,” AHS Specialists’ Conference on Aeromechanics Design for Transformative Vertical Flight, San Francisco, CA, 2018.
  3. UAM UML-4 ConOps  https://sti.nasa.gov/
  4. FAA UAM ConOps 1.0 https://nari.arc.nasa.gov/sites/default/files/attachments/UAM_ConOps_v1.0.pdf
  5. National Academies Report: https://www.nap.edu/catalog/25646/advancing-aerial-mobility-a-national-blueprint
  6. Wright, J., and Aubert, R., “Icing Wind Tunnel Test of a Full Scale Heated Tail Rotor Model,” AHS 70th Annual Forum, Montreal, CA, May 2014. [AHS 2014-0104]
  7. Kreeger, R., Work, A., Douglass, R., Gazella, M., Koster, Z., and Turk, J., "Analysis and Prediction of Ice Shedding for a Full-Scale Heated Tail Rotor," AIAA Atmospheric and Space Environments Conference, Washington, D.C., June, 2016. [AIAA 2016-3443]
  8. Sehgal, A., and Ernst, R., “MQ-8 Fire Scout Icing Solution Challenges,” AHS 72nd Annual Forum, West Palm Beach, FL, 16-19 May, 2016.
  9. Avery, A., and Jacob, J., “Evaluation of Low Altitude Icing Conditions for Small Unmanned Aircraft,” AIAA 9th Atmospheric and Space Environments Conference, Denver, CO, 5-9 June, 2017. [AIAA 2017-3929]
  10. Han, N., Hu, H., and Hu, H., “An Experimental Investigation to Assess the Effectiveness of Various Anti-Icing Coatings for UAV Propeller Icing Mitigation,” AIAA Aviation 2022 Forum, Chicago, IL, June, 2022. [AIAA 2022-3964]
  11. Schneeberger, G., Palacios, J., and Wolfe, D., “Development of Ice Protective Surfaces via Reduction of Surface Roughness,” AIAA Aviation 2022 Forum (virtual), June 2020. [AIAA 2020-2803]
  12. Dumont, C., Pellicano, P., Smith, T., and Riley, J., “Results From a Full-Scale Propeller Icing Test,” 46th AIAA Aerospace Sciences Meeting and Exhibit, Reno, NV, January 2008. [AIAA 2008-432]

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