Electrified Aircraft Propulsion (EAP) Educational Briefing

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Electrified Aircraft Propulsion (EAP)

Educational Briefing

12/ 19 /201 8

M. Deans, R. Jansen, P. Loyselle, S. Schnulo, C. Smith, I. Delgado National Aeronautics and Space Administration - Glenn Research Center C. Stelter National Aeronautics and Space Administration - Langley Research Center

Agenda

• Guidelines/Rules

• Proposal Best Practices

• Overview of NASA’s Vision for Electrified Aircraft

Propulsion (EAP)

• Overview of the needs in the specific area of

battery technology, as it relates to EAP

• Overview of the needs in the specific area of

additively-manufactured, multi-functional heat

exchanger technology, as it relates to EAP

Guidelines/Rules

Discussion Guidelines/Rules

• This is an educational brief and includes discussions of general programmatic

goals

– NASA will not discuss if/how any of these goals are included in a given ongoing or

forthcoming solicitation

– For any solicitation, please refer to the goals/metrics stated within those requests for

proposals (RFPs)/solicitations; proposals must be responsive to the stated requirements of those specific solicitations and not to any other stated or perceived need

– Forthcoming solicitations may also contain other guidance, technical needs, and or

challenge areas; please review solicitations fully • Because of pending/formulating proposals, NASA will not assess, prioritize,

discuss, or answer questions on proposed or ongoing technologies/solutions

by those in this forum

– Also note that this is an open forum with others in attendance

Proposal Best Practices

Small Business Innovation Research (SBIR) & Small

Business Technology Transfer (STTR ) Programs - Overview

• Because of ongoing/pending/future proposals/solicitations, specifics of the SBIR/STTR solicitation will not be discussed in this forum • SBIR is a Small Business set - aside program for Federal R&D – including potential for commercialization • STTR is a sister program for cooperative R&D between small business concerns and U.S. research institutions – including potential for commercialization • For more information on NASA’s SBIR/STTR program, please see https://sbir.nasa.gov /

– The next Phase I solicitation cycle is anticipated to start in ~early to mid January

– Note that public listings of past awards and companies are searchable at

https:// sbir.nasa.gov/advanced_search • See the Small Business Administration website for additional helpful information including links to other agency SBIR sites/solicitations : https://www.sbir.gov /

SBIR/STTR Proposal - Advice

• The proposal process begins right now, not after the solicitation is released.

• Writing a winning a proposal is a long term process that involves:

– Understanding the needs and interests of NASA

– Interacting with the technical community

– Read the solicitation carefully

• Do not assume it is the same as last year

– Reread it again, your competition did

• Provide all of the required information, forms, and surveys

• Make sure you properly address all of the listed evaluation criteria from the

solicitation

– Organize it in a way that makes it clear to the reviewers

• Explain (early and concisely) how your effort will benefit NASA interests .

SBIR/STTR Proposal – Writing Responsive Proposals

• Know your Vision

– T arget your work/proposal to the appropriate subtopic – be responsive

• Know the Context

– Read the solicitation carefully

– Understand the scientific and technological importance of your idea (who cares, big picture)

– Understand the programmatic relevance of your idea

– Use National Academy reports, conference reviews, NASA Strategic Plans, Roadmaps for guidance • Justify Why You and Not Somebody Else

– Justify and clearly define your firm and roles of the team

• Define the State of the Art

– Demonstrate your grasp of the field; offer a short, well - researched overview of

relevant science and technology; cite key references

– Demonstrate an understanding of the state of the art and how you will advance it

SBIR/STTR Proposal – Writing Responsive Proposals

• Describe Your Contribution

– What will your work contribute to the field? Scientific knowledge, increased capabilities, applications to NASA’s missions?

– Don’t over - claim or over - reach; justify the claimed factors of gains

• Defend Your Proposal

– Can you do the job on schedule/budget?

• Understand and Respect Your Audience

– Make sure your abstract, charts, etc. are clear/concise; make it so the reviewer can easily identify the information for the evaluation criteria

– Make sure you address all selection criteria; somebody will be checking

– Make your key idea clear; repeat

– Neatness, including spelling and grammar, counts

– Reviewers are NASA subject matter experts; they understand the field and technical area

but may not already know the details of your specific innovation, especially if it differs significantly from the state of the art

SBIR/STTR Proposal – Writing Competitive Proposals

A competitive proposal will clearly and concisely: • Describe the proposed innovation relative to the state of the art AND the relevance/significance of the proposed innovation to the needs of the subtopic

– Compare your anticipated/target metrics vs. the state of the art; state both

– State how your metrics address the subtopic metrics/goals; if improving a different

subcomponent metric that feeds into improvements on the stated subtopic metric or goal, discuss how these metrics are derived/involved • Address the scientific, technical, and commercial merit and feasibility of the proposed innovation, and its relevance and significance to NASA interests .

– State what the known risks/challenges are and how your innovation and/or

development plan will address them

– Work Plan: What will be done, where it will be done, and how the R/R&D will be

carried out • Clear development plan with clear metrics and decision gates where appropriate

– For all of these, describe also the ‘ why ’

SBIR/STTR Proposal – Writing Competitive Proposals

A competitive proposal will clearly and concisely (continued): • Provide a strategy to addresses technical , market, and business factors pertinent to the development , demonstration, and transition into products and services for NASA mission programs, the commercial aerospace industry, and other potential markets and customers .

– Is there a demonstrated understanding of what is needed to infuse this concept

– End - applications may inform what key developments are needed and justify approach

– Is your design and development/test plan informed by end - applications to justify further investment and encourage transition to use?

– Do key milestone tests and prototypes/deliverables justify continued

investment/acceptance of the technology ?

– Is your development lifecycle within and beyond this development program continuous or

does it leave gaps ?

STTR: Provide information to convince NASA that the cooperative effort is a sound approach for converting technical information resident at the Research Institution (RI) into a product or service that meets a need described in a Solicitation research topic.

References: • For source material for this presentation and additional guidance, please see the SBIR website; one helpful tool is the interactive participation guide and links therein : https:// sbir.nasa.gov/guide • Additionally, some presentation material referenced from “Writing Responsive Proposals”, B.

Benvenutti, Z. Burkland, M. Davidson. Innovation & Opportunity Conference: Advancing Aerospace and Defense . Nov. 7 - 8, 2018. Aurora, Colorado

Overview of NASA’s Vision for

Electrified Aircraft Propulsion

(EAP)

Slides from: NASA’s Vision for Aircraft Electric Propulsion and Power Jay Dryer, Director, Advanced Air Vehicles Program Aeronautics Research Mission Directorate July 12 , 2018 Representative Electric Aircraft Missions and Related Battery Needs Ralph Jansen, NASA Glenn Aeronautics Project Office www.nasa.gov | 1 September 25, 2017

Global Growth in Aviation

2017 2036

4 BILLION

7.8 BILLION

PASSENGER TRIPS PASSENGER TRIPS Asia - Pacific

41,030

78%

Market is Nearly New Aircraft Deliveries of New Aircraft

40% Deliveries are

Single Aisle Class

$6.1 Trillion

of New Aircraft (including Regional Market Value Deliveries Jets) Guangzhou - Foshan, China

New Market for Urban Air Mobility

20.5M Moscow, Russia Delhi, India Beijing, China New York, USA 16.1M 24.9M 21M 20.6M Seoul - Incheon, S Korea Top 20 Megacities 23.5M Karachi, Pakistan 22.1M Tokyo, Japan 37.8M Cairo, Egypt 15.6M Osaka - Kobe - Kyoto, Japan Los Angeles, USA 17.4M 15M Manila, Philippines Mexico City, Mexico Mumbai, India 37.8M 19.4M 17.7M Kolkata, India 14.6M Shanghai, China Dhaka, Bangladesh 23.4M Sao Paulo, Brazil 15.7M 20.3M Bangkok, Thailand 14.9M Jakarta, Indonesia 30.5M Large projected market – McKinsey analysis of demand by 2030 in 15 major U.S. cities: • 500 Million annual UAS package deliveries • 750 Million annual passenger trips Extrapolation to the global market would likely increase demand by 5 to 10x Top 20 Megacities by population data from allianz.com 03.16.15

Benefits of Electrified Aircraft Propulsion

• Improvements to highly optimized aircraft like single - aisle transports – Potential fuel burn reduction estimated using turbo electric distribution to Boundary Layer Ingestion thruster in addition to other benefits from improved engine cores or airframe efficiencies.

• Enabling new configurations of VTOL aircraft – Enable new VTOL configurations with the potential to transform transportation and services.

• Revitalizing the economic case for small short - range aircraft services – The combination of battery - powered aircraft with higher levels of autonomous operations could reduce the operating costs of small aircraft operating out of community airports resulting in economically viable regional connectivity.

Types of Electrified Aircraft Propulsion

Electrified Aircraft Propulsion (EAP) systems use electrical motors to provide some or all of the thrust for an aircraft • Turboelectric systems use a turbine driven generator as the power source . Partially turboelectric systems split the thrust between a turbo fan and the motor driven fans .

• Hybrid electric systems use a turbine driven generator combined with electrical energy storage as the power source . Many configurations exist with difference ratios of turbine to electrical power and integration approaches .

• All - electric systems use electrical energy storage as the only power source .

Example Missions

THIS IS NOT STRICT DEFINITIONS, THEY ARE JUST A FEW REPRESENTATIVE EXAMPLES Mission Number of Typical Typical EAP Passengers Range Speed Configurations • All electric Urban <=4 <50 miles <200 miles/ hr • Hybrid Electric Mobility • Hybrid Electric Thin Haul <=9 <600 miles 150 - 250 miles/ hr • Hybrid Electric Short Haul 40 - 80 <600 miles 350 - 500 Aircraft miles/ hr • Hybrid Electric Single Aisle 150 - 190 900 mile typical ≈600 miles/ hr • Turbo Electric mission, 3500 mile maximum range

Electrified Aircraft Propulsion Barriers by Vehicle Class

Technology Area Urban Air Mobility Thin Haul / Short Single - Aisle Haul Power Distribution • Flight Critical • Flight Critical • Flight Critical • High Voltage (>1000) Energy Storage • 400 W - hr /kg (at • 400 W - hr /kg (at system level) system level) On Aircraft Power • Light Weight / • Flight Weight • Combined thrust Generation / High Efficiency MW and MW power Turbines IC engine, turbogenerator extraction turbine, or fuel cell • Projected PAI Propulsion / • Highly Airframe Integration distributed benefit Autonomy • No pilot • Reduced pilot operation operation

Exploring Concepts for Urban Air Mobility

Open, publicly - available reference vehicle configurations − Cover a wide range of technologies and missions − Provide focus for trade studies and system analysis − Assess failure modes and hazards of concept vehicle electrified propulsion architectures - Fifteen passengers (3000 - lb payload) - 8x50 = 400 - nm range - One passenger (250 - lb payload) - turbo - electric tiltwing - 50 - nm range - electric quadrotor - Six passengers (1200 - lb payload) - Six passengers (1200 - lb payload) - 2x37.5 = 75nm range - 4x50 = 200 - nm range - turbo - electric Lift+Cruise VTOL - hybrid side - by - side helicopter

Learning from Development & Flight with the X - 57

X - 57 “Maxwell” • Cruise - sized wing: enabled by distributed electric propulsion system for takeoff/landing performance • High - efficiency cruise All Electric propellers: electric motors mounted at wingtips • All - electric propulsion system: 40+ kWh battery, 240 kW across 14 motors Cruise System • Fully redundant powertrain High Lift System • Documented safety reviews and safe operational procedures Key learning on more electric systems that can help the community

Example Short Haul

• NASA PEGASUS: Parallel Electric - Gas Architecture with Synergistic Utilization Scheme (PEGASUS) is a novel hybrid electric regional aircraft that strategically locates multiple electric and hybrid electric propulsors to obtain aerodynamic benefits. 48 Passengers, Range 200 - 600 miles, speed 300 knots (345 miles/ hr ) Batteries assumed to be 500W - hr/kg

Example Single Aisle Partial Turboelectric

• NASA STARC - ABL: fuel burn reduction 7 - 12%, same range, speed, airport infrastructure. Same turbine/airframe technology, advanced 2 - 3MW power system, BLI, turbogenerator integration • Boeing SUGAR Freeze: fuel burn reduction 56% for 900 mile mission, utilizes a truss - braced wing combined with a boundary - layer ingesting fan in an aft tail cone to maximize aerodynamic efficiency. The aft fan is powered by a solid oxide fuel cell topping cycle and driven by a superconducting motor with a cryogenic power management system

Example Single Aisle Parallel Hybrid Concepts

• Airframe/propulsion remains relatively decoupled Boeing Sugar Volt • Parallel hybrid, 150 passenger, 900 nm • 1.3 and 5.3 MW machines considered • Fuel off - loaded 750 W - hr/kg batteries charged from grid • 60% fuel burn reduction UTRC hGTF – On - going, optimized geared turbofan engine for cruise by adding boost power for take off and climb • Parallel hybrid, 150 passenger, 900 nm • 2.1 MW machines, 1000 W - hr/kg batteries Low Spool High Spool • 6% reduction in fuel burn and 2.5% reduction in energy usage R - R LibertyWorks EVE – On - going, parametrically optimized engine with hybrid climb & cruise segments • Parallel hybrid, 150 passenger, 900 nm • 28% reduction in fuel burn for a 900 - nm mission • Up to a 10% total energy reduction for a 500 - nm • Optimizing for minimum fuel usage predicts an 18 percent reduction in total fleet fuel usage.

Battery Needs Based on Missions

THESE ARE NOT STRICT REQUIRMENTS, THEY ARE BASED ON A FEW REPRESENTATIVE EXAMPLE STUDIES Mission Power Level Specific Energy Cycles Reliability Urban Air 200 - 500kW 250 – 400 Whr /kg ≈25 - 50/day Flight Critical Mobility 12,000/year Thin Haul 200 - 500kW 300 – 600 Whr /kg ≈4 - 12/day Flight Critical 2600/year Short Haul 500 - 1500kW 300 – 600 Whr /kg ≈4 - 12/day Flight Critical Aircraft 2600/year Single Aisle 1000 - 5000kW 750 – 1000 Whr /kg ≈4 - 8/day Important / Flight minimum 2000/year Critical

Conclusion

• There is potential for aircraft with more electric propulsion

systems to have tremendous impact on a number of

aviation markets.

• Small prototype electric aircraft are flying (1 - 2 persons).

• NASA and Industry are making investments in technology to

enable larger electric aircraft.

• NASA and Industry are making investments in aircraft

demonstrations and certification standards to help enable

the transition to certified production aircraft.

• NASA is working to address some of the key enabling

technical challenges to realize this new capability.

Overview of Battery Technology

Battery Needs Based on Missions

High Specific Energy

> 400 Whr /kg battery level

• Higher energy chemistry

• Improved, lightweight packaging

• Multifunctionality

• Improved functional thermal operation window

High Specific Power

Capability to respond to aircraft power needs

without sacrificing specific energy density

• Hybrid chemistries

• Electrode configurations

• Cell and / or battery configurations

• Rapid recharge capability

Cycle Life

High Cycle life without sacrificing specific energy

density

Cycles per year: 2000 - >10,000

• Improved battery chemistries

• Improved electrode configurations

• Improved cell and / or battery configurations

Safety

Safe battery design without sacrificing

performance and/or specific energy density

• Improved battery chemistries

• Nonflammable components

• Thermal runaway propagation prevention

• Improved cell and battery configurations

• Improved sensing and predictive modeling

Reliability

Minimize cell and battery failures

• Improved battery chemistries to improve

consistent performance

• Wide environmental operating envelope

• Wide performance operating envelope

• Improved cell and battery configurations

• Connections

• FOD

• Matching Impedance

• Minimize moving parts

Thermal

Minimize the impact of the thermal subsystem to

the overall battery specific energy density

• Wide environmental (temperature) operating

envelope

• Improved battery chemistries with large range

of operational temperature

• Improved cell and battery design

• Optimize passive thermal rejection

• Improved thermal materials

Advanced Configurations

Optimal designs to maximize specific energy

densities, performance, reliability and safety

• Multifunctionality

• Structure

• Thermal

• Other?

• Improved cell designs

• Advanced packaging concepts

• Advanced fabrication methods to improve

• Utilization

• Specific Energy Density

• Performance metrics

Conclusion

There is a need for significant advancements in energy

storage technologies for future aircraft needs

Higher Specific Energy

Higher Specific Power

Higher Cycle Life

Safety

Reliability

Thermal Management

Overview of Heat Exchanger Technology

Technical Challenges Overview

• The problem: Electric aircraft propulsion

(EAP)requires electric components that produce low

grade heat loss. Managing this heat requires heat

exchangers, which in turn add a weight penalty that

may cancel out the benefits of EAP.

• What advanced materials or manufacturing processed

can make the most lightweight, multifunctional heat

exchangers?

• What other functions could a heat exchanger provide

that might offset its weight penalty? (i.e. structural,

managing heat from another system, etc.)

• What applications of a multifunctional heat exchanger

can produce the most impact?

Possible Application: Small Recuperated Turbine Engine

• On Demand Mobility (ODM) may find benefit in a hybrid solution.

• Fully electric vertical takeoff and landing (VTOL) vehicles are have limited range abilities.

• Hybrid electric may allow the completion of more missions in a day because aircraft will not be on the ground as long or as often charging. This may also lead to a reduction in the number of vehicles required to meet demand, driving down cost.

• Hybrid electric might also allow the service of “megaregions” (bottom right), or people that commute further distances than the range that can be supported by batteries.

• Further, hybrid electric may offer a near term solution as battery technology continues to mature to the energy densities needed for air taxi operations.

Nelson, G.D. and Rae, A., “An Economic Geography of the United States: From Commutes to Megaregions,” PlosOne , Nov. 2016.

The Problem: Gas Turbines lose some efficiency benefit at small

power scales

• Turbine engines 0.450 have roughly 2x the specific power 0.400 of Internal Combustion Turbine engines 0.350 engines at small power scales • However, at small 0.300 power scales they

GOAL

are not as efficient 0.250 (right) Improving Efficiency • Can we improve 0.200 the efficiency of Intermittent internal combustion

SFC (kg/kWh)

turbine engines 0.150 while preserving 0 200 400 600 800 1000 the specific power

Shaft Power (kW)

benefit?

Why recuperation?

• Recuperation uses waste heat from the turbine to heat up air going into the combustor for an efficiency benefit • Recuperators add significant weight to the system.

• Can we design a recuperated turbine engine system without a weight penalty by leveraging: • Advanced materials?

• Additive manufacturing?

• Multifunctionality?

Benefits of Ceramic Matrix Composites

in Propulsion Systems

CMCs are enabling materials for aero - propulsion and other high temperature extreme environment applications SiC/SiC CMCs offer significant advantage over superalloys at 1/3 density 2700º F CMC Coated CMC Components from NASA Programs Jim DiCarlo

Additive Manufacturing of CMCs

Material and Additive Conventional Process Challenges Manufacturing Manufacturing ▪ Property and behavior of ▪ Small series of • Customized parts in starting materials ceramic parts can be small volumes are time manufactured rapidly ▪ Sintering and consuming and and cost-effectively.

densification challenges expensive to produce.

▪ Specific molds are not • Complex shape ▪ Process modeling required.

fabrication issues: mold ▪ Mechanical behavior design, dimensional ▪ Different designs can tolerances, etc..

be optimized (no major ▪ NDE and in-situ damage cost of changes) • Manufacturing of characterization multifunctional parts are ▪ Parts with significant ▪ Material and property challenging.

geometric complexity.

databases Materials and Long term research Efforts in this very processing efforts have now promising field challenges are resulted in various are now quite similar applications. underway.

Applications of Additively Manufactured SiC

• SiC is a lightweight (3.2 g/cc), thermally conductive (~40 w/mK) material with high temperature capability (>1200 ° C).

• Innovative manufacturing development of SiC could enable heat exchangers with up to 50% weight reduction, compared to metals.

• Lightweight heat exchangers can be used to improve the efficiency small of hybrid electric aircraft- such as the ones envisioned for On-Demand Mobility.

• Initial studies have shown that ceramics, such as SiC can be printed, but extensive studies on the material optimization and durability have yet to be explored.

Metals for Additively Manufactured Heat

Exchangers and Heat Sinks

• Due to the multiple properties involved in selecting the material with which to construct the heatsink, sometimes the best material is not one which is necessarily the strongest in any one property.

• Sometimes constraints such as use temperature over - ride otherwise attractive properties.

• In this way, a high performance aluminum alloy may be ideal for certain applications (like a structural heatsink for thermal management of electrical systems) by non - ideal in others (such as a high temperature jet turbine recuperator ).

• Metals often excel where impact resistance and toughness are required with lightweight alloys becoming feasible for lower use temperatures.

• Metals (instead of ceramics) are also useful where both thermal management and mechanical strength are desired in the same part, such as this structural heatsink:

Possible Application: Thermal Structural Management

for Enabling Electrified Aircraft

The Problem: Component inefficiencies produce low - grade waste heat generated in Tilt - Wing Lift+Cruise motors, batteries, and power electronics for electrified aircraft.

Side - by - Side X - 57 Helicopter Ref: Silva, Christopher, et al. "VTOL Urban Air Mobility Concept Vehicles for Technology Development." 2018 Aviation Technology, Integration, and Operations Conference . 2018.

Ref: https://www.nasa.gov/aeroresearch/X - 57/technical/index.html

Need: A Multifunctional Aircraft Skin Panel

• Can a system - level light - weight benefit be shown for a



structurally/thermally optimized aircraft skin panel ?

• Can an efficient path to manufacturability be shown for



a structurally/thermally optimized aircraft skin panel ?

 Aircraft skin panel includes stiffened structure.

Can a system - level light - weight benefit be

shown for a structurally/thermally optimized

aircraft skin panel?

• Heat Exchanger Design Space – Lightweight topologies – e.g. lattice frame materials, branching structures?

• Aircraft Location: wing, fuselage, nacelle • Heat exchanger integrated Into the aircraft skin • Meets structural requirements • Optimized for weight • Demonstrated light - weight benefit at a system - level

Can an effective path to manufacturability be

shown for a structurally/thermally optimized

aircraft skin panel?

• Material Selection • Additive Manufacturing

– High thermal performance – Prototyping – High mechanical – Complex topology performance – Scalability – Low density – Maintaining performance – Manufacturability by – Path to certification advanced additive methods

Q&A and Introductions

• You are welcome to ask questions but please be aware of the guidance/rules

• When speaking, you are welcome (but not mandated) to introduce yourself

and your company/institution if you so choose for the awareness of all of

those participating

Guidance/Rules: • This is an educational brief and includes discussions of general programmatic goals – NASA will not discuss if/how any of these goals are included in a given ongoing or forthcoming solicitation – For any solicitation, please refer to the goals/metrics stated within those requests for proposals (RFPs)/solicitations; proposals must be responsive to the stated requirements of those specific solicitations and not to any other stated or perceived need – Forthcoming solicitations may also contain other guidance, technical needs, and or challenge areas; please review solicitations fully • Because of pending/formulating proposals, NASA will not assess, prioritize, discuss, or answer questions on proposed or ongoing technologies/solutions by those in this forum – Also note that this is an open forum with others in attendance