Electric Commuter Transport Concept Enabled by Combustion

Electric Commuter Transport Concept Enabled by Combustion Engine

Range Extender

Georgi Atanasov, Jasper van Wensveen, Fabian Peter, Thomas Zill

DLRK 2019 • Chart 1

Outlines

DLRK 2019 • Chart 2 Electric 19-Seater Aircraft with Range Extenders

Background and Objectives.

Conceptual-Level Aircraft Sizing of a Hybrid-Electric 19-Seater

Results and Assessment

Conclusions and Outlook

Background and Objectives

A collaborative project between the DLR and Bauhaus Luftfahrt:

� Re-introduction of small regional aircraft with up to 19 passengers.

Approach:

� 19-seater market analysis

� 19-seater aircraft data base for support

� Assessment of feasible concepts

Objectives of this study:

� A conceptual aircraft design that answers the market analysis results


Design Goals

Market research data:

• Extremely short utilization distances of

19-seater aircraft


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Trip Distance from x km up to y km

Design aim:

• 19-seater aircraft with fully electric flight

capability.

• State-of-the-art electric components at

prototype level.

• Certification under CS 23

• Competitive payload-range characteristics

� Market suitable for fully electric flight Cu

mu

lative

sh

are

of

flig

hts

Trip Distance [km]

Propulsion Architecture


Con

Con

Kero

sene

Tank

Gas

Turbine

eMotor Battery

• Classical twin propeller configuration:

o Low-risk, dependable conceptual-level results.

• E-Motors:

o Sized for take-off & all-electric operation.

• Range extender:

o In parallel to e-motors, with a coupling / decoupling device.

o For full IFR mission reserves with kerosene.

o For range flexibility with kerosene.

o Sized for loiter speeds @ 10000ft.

• Batteries:

o Sized for all-electric operation.

o Must not consider mission reserves.

Configurational Aspects


co

n

Propulsion mass directly

supported by the landing gear

2t 2t4t

Favourable mass distribution

for the wing in flight

0%

100%

Po

we

r

Altitude

E-Motor PowerGas Turbine Power

Pressurized cabin complementing

the e-motors‘ lack of power lapse.

Landing gear to wing root due

to space allocation

wikipedia.com

Designation - E19

Conceptual Design Model Calibration


• Refined troughout previous studies

• Dependable for similar configurations

� Used as a base for this study

Aircraft Sizing Model Based on Do228

Uncertainty: E19 configuration is different

BAe Jetstream 31

B1900D

Model Validation and Calibration on Similar to E19 Configurations

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Range [km]

B1900D

B1900D ref. data

BAe JS31

Bae JS31 ref. data

Top-Level Aircraft Requirements (TLARs) & Assumptions


TLAR Value Unit Remarks

MTOM Limit 8618 Kg CS23 Limit

Max Payload 1805 Kg Same as BAe JS31

Min Cruise Altitude 10000 Ft

Ceiling Altitude 25000 Ft Same as BAe JS31

Diversion Mission 100 Nm For IFR flight rules

Approach Speed 109 Kts Similar to BAe JS31

Takeoff Field Length 1440 m Same as BAe JS31

Same technology as the Bae JS31:

• Airframe structure

• Systems

• Gas turbine

• Furnishings & Operator Items

Segment Time [min] Energy [kWh]

Taxi out 3.0 0.8

Take-off 1.1 24.7

Approach & Landing 2.0 6.1

Taxi in 3.0 0.8

Total 9.1 32.4

Allowances

Sizing Results


El. Power TrainTot. Mass Tot. Power Eff.

[kg] [kW] [-]

E-Motors 253 1251 95.0%

Controllers 12 1321 98.0%

Cooling 44 89 -

Power Distr. 66 1321 99.7%

Battery 2018 1352 -

Sizing Model Results Value Unit

Max. Takeoff Mass (MTOM) 8618 kg

Design Fuel (IFR Reserves Only) 192 kg

Maxi. Zero-Fuel Mass 8426 kg

Max. Payload 1805 kg

Operating Empty Mass (OEM) 6621 kg

Operator's Items 475 kg

Manufacturer's Empty Mass 6146 kg

Furnishings 270 kg

Systems 650 kg

Propellers + Range Ext. (incl

Systems)388 kg

Airframe Structure 2446 kg

El. Power Train Budget 2329 kg

State of the Art Technology Assumptions @ Prototype Level

5kW/kg @ 1680rpm

115kW/kg (Siemens)

1 kW/kg (losses)

• 230 Wh/kg

• 690 W/kg

� Effective: 160 Wh/kg

• 90% State of Charge (start of Mission)

• 20% State of Charge (end of Mission)

Battery Pack

E19 Geometry Overview


Parameter Wing HTP VTP

Area [m2] 33.2 8.2 6.1

Aspect Ratio [-] 12.0 5.2 1.5

MAC [m] 1.77 1.27 2.17

¼-Chord Sweep [°] 1.8 3.0 36.0

Rel. thickness [-] 16% / 12% 13% / 12% 13% / 12%

E19 Payload-Range Characteristics


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Range [km]

50%

50% 25%

75%10%

90%

6%

94%

• Mostly electric operation in the typical utilization range

• Extended range capability for airline flexibility

88% of

Missions

E19 Power Profile


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AT

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time [min]

Battery Power

Altitude

Electric Mission (190km)

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GT* + E-Mot Power

E-Motor Power

Altitude

Hybrid Mission (340km)

• 10000ft cruise – too short for higher altitude.

• No pressurization offtakes at this altitude.• Climbs higher and faster to improve time

performance at the bigger distances

Payload-Range Comparison


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B1900D

BAe JS31

Do228

E19Typical

Utiliza-

tion

Parameter Unit Do228 BAe JS31 B1900D E19

MTOM kg 6400 6950 7766 8618

Sref m2 32 25.2 28.8 33

Span m 17 15.9 17.75 20

cLcruise - 0.3 0.55 0.45 0.75

L/Dcruise - 10.0 14.6 12.1 19.4

psfcGT,cruise kg/kWh 0.34 0.32 0.33 0.35

� High MTOM is mitigated by improved L/D

Mission Performance


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L/D

cL

BAe JS31

B1900D

E19

Cruise Points

• E19 � velocity traded for efficiency.

• Penalty most prominent at the longer missions.

• Less affected at the typical utilization range.

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tim

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Mission Distance [km]

E19

JS31

B1900D

Do228

88% of the

missions


Sizing Requirements for the Hybrid Chain

Electric 19-Seater Aircraft with Range Extenders

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[email protected] Payload - LRC

[email protected] Payload - MC

[email protected] Payload

~88% of the

operations

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Emmissions if all 2018 flights were operated by E19

Emmissions if all 2018 flights were operated by the

Do228 at efficient cruise speed

• With renewable energy for recharging, ~70% emissions reduction potential at the 19-seater market

• If current electric mix in Germany is used � a potential of ~45% emissions reduction remains


Conclusions

The conceptual design study conclusions:

• State-of-the-art electric power technology is potetially suitable for the 19-seater market.

• > 70% fuel savings on average are potentially feasible on this market.

• > 40% CO2 emission reduction possible, if battery charging with the German electric mix of today is assumed.

Further efforts needed:

• Operational assessment, including charging during turnaround and life-cycle assessment.



Outlook


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Range [km]

Fully Electric

50% Electric Power

25% Electric Power

10% Electric Power

6% Electric Power

E19 Payload-Range

2x Better

Batteries

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Fully Electric

50% Electric Power

25% Electric Power

12% Electric Power

Payload-Range

10

0%

PE

• New battery technology could improve performance without redesigning the aircraft.

• The approach is scalable to bigger aircraft for similar range performance.


Thank you for your attention!


Documents

Electric Commuter Transport Concept Enabled by Combustion