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Purdue-Wright Senior Design Project Background Presentation

Deliverable I

AAE 45100 Spring 2016

Purdue University

Professor Sullivan

Conor Donahue

David Shultz

Veronica Wiley

Wills Johnston

Aleksandra Dervisevic

Andres Velez-Valencia

Adam Freeburg

Thomas Adamson

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Overview

History of electric aircraft

Constraint and weight analysis, including examples

Electric motor and battery research

Hybrid aircraft examples/past designs

Piper Cherokee analysis

Next steps and schedule for the semester

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History of Electric Aircraft

MIT Monarch

1984
Used batteries charged by pedaling to power the aircraft

Militky MB-E1

1973
First full size manned aircraft to fly solely on electric power.
12 minute flight time

Hugues Duval MC15E Cri-Cri

2010
Fastest electric aircraft (176 mph)

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Modern Electric Aircraft

Pipistrel Taurus G4

Winner of the 2011 Green Flight Competition
200 mile range

NASA LEAPTECH

Converting a Tecnam P2006T
18 Engines utilizing distributed electric propulsion

e-Genius

250 mile range and in work to double that range
60 Decibel takeoff noise.

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Constraint analysis overview

Constraint Analysis:

Used to determine an approximate wing loading (N/m^2) and power loading (W/N) value to be used in the sizing analysis for the electric and gas powered aircraft
Optimal values are chosen from a graph of the wing loading vs power loading for the following stages of flight

Takeoff
Maximum speed
Landing
Ceiling
Rate of Climb
Turns

Pilatus PC-12

Piper Cherokee

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Constraint analysis electric vs ICE, Pilatus PC-12

ICE Electric

*

Takeoff

Max Speed

Landing

Ceiling Rate of Climb

Turns

Takeoff

Max Speed

Landing

Ceiling Rate of Climb

Turns

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Constraint analysis electric vs ICE, Piper Cherokee

ICE Electric

Takeoff

Max Speed

Landing

Ceiling Rate of Climb

Turns

*

Takeoff

Max Speed

Landing

Ceiling Rate of Climb

Turns

*

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Weight sizing analysis overview

Weight Sizing Analysis:

Wing loading (N/m^2) and power loading (W/N) values from constraint analysis are used to find the fuel weight fractions for take-off, climb and best range cruise

Portions of flight where electric propulsion could be most beneficial

Weight fractions are then used to calculate takeoff weight
Gas powered weight sizing gives a baseline - electric weight sizing is compared to find ideal battery density

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Weight Sizing - PC-12 (electric)

Battery energy density approximation for full range aircraft:

Weight sizing targets

Target cruise distance: 2800 km
Target total takeoff weight: 7740 lbs

Taken from baseline weight sizing of PC-12 ICE

Required input to reach targets:

K_batt = 1,190,000 J/N (3240 Wh/kg)
~20 times today’s average battery energy density

Outputs:

Power required: 620 kW

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Weight Sizing - Piper Cherokee (electric)

Battery energy density approximation for full range aircraft:

Weight sizing targets

Target cruise distance: 867 km
Target total takeoff weight: 2900 lbs

Taken from baseline weight sizing of Cherokee ICE

Required input to reach targets:

K_batt = 610,000 J/N (1660 Wh/kg)
~10 times today’s average battery energy density

Outputs:

Power required: 160 kW

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Weight Sizing - Overview

Battery technology needs to significantly increase in order to compete with ICE aircraft.

Ratio of gas to battery energy density today: ~7
Gas still the much more viable option

Using today’s average battery density of 165 Wh/kg, both aircraft could only fly for approximately 30 minutes (Assuming it’s possible to provide the required power)

The sized PC-12 requires 620 kW of power
Sized Piper Cherokee is more reasonable requiring 160 kW

Regarding a hybrid approach, electric would be beneficial to use during takeoffs and landings.

Cruise distances severely limited for all electric passenger aircraft

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Battery Betterment Projections

K batt (for 137 km cruise) = 164.8 Wh/kg (60,480 J/N)
K batt (for 2800 km cruise) = 3240 Wh/kg (1,190,000 J/N)

*Based off Pilatus PC-12 combustion statistics and weight sizing analysis to create an electric weight sizing analysis for similar aircraft

~8% Li-Ion energy density increase per year over the last 30 years (NASA)

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Research: Batteries

Types:
Cylindrical
Pouch

Chemistry	Specific Energy Densities (Wh/kg)	Notes
Li-Ion/Li-Po	100-265	Among most popular, come in various shapes
LiFePO4	90-130	Longer life than Li-Ion, lower energy density
LiSO2	~350 (up to 500 demonstrated)	Common in aerospace, commercialization in progress, ideal for low-cont. current, primary batteries
LiSOCl2	500-700	Ideal for low-cont. current, safety limits civilian applications, primary batteries
Li-Air	>1000	Primary or secondary batteries, still highly developmental

Prismatic

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Electric Motors

JOBY JM2

20.9KW (28.02736 hp)
4kg
Inrunner
$3,200
100-600V
55kw (74.8 hp)

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Electric Motors

EMRAX 228 by Enstroj

55kw (74.8 hp)
12 kg
Outrunner
600V at max power
Expensive, call for price

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Electric Motors

SIMOTICS prototype by Siemens

Not so distant future
260kw (348.7 hp)
50 kg

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Hybrid aircraft examples/past designs

Axter System

Designed as an engine retrofit to help in case of engine failure, allowing for 7 minutes of battery driven flight
Adds 40 hp (30 kW) to combustion engine

Improve takeoff distance
Climb speed
Allow for shorter landing distances by running in reverse
Compensates for engine loss power at high temperature conditions

Can retrofit any plane with Rotax 912 or 914 engines with an Emrax electric motor

Electric Motor Gas Engine

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Hybrid aircraft examples/past designs

Watts Up

Utilizes a Song UL frame with a Honda engine with an electric motor coupled on the same drive pulley
Electric motor used during:

Takeoff
Climb
Other high power required periods while the gas powered engine runs during cruise

Uses 30% Less Fuel

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Hybrid aircraft examples/past designs

Pipistral Panthera Hybrid

4 seater, single propeller, hybrid engine aircraft
145 kW hybrid electric engine
100% Electric powered take-offs and landings

Noiseless during when using 100% electric power

> 1000 nautical mile range

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Hybrid aircraft examples/past designs

Boeing Sugar Volt

154 Commercial Passenger aircraft
Makes use of hFan hybrid engine (turbofan)

Short range flown mostly on electric power
Long range flown mostly on jet fuel

Truss-Braced wing allows for high aspect ratio

5-10% improvement in fuel consumption from wings alone.

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Hybrid aircraft

As can be seen, most hybrid electric aircraft designs use a form of a parallel hybrid engine.

Mission segments may require full use of either gas or electric power, or a combination of both

Analysis of mission segments important to optimize when the aircraft uses electric power, gas power, or both.

Hybrid Engine/Aircraft	Takeoff/Landing	Cruise
Axter	Electric + Gas	Gas
Watts Up	Electric + Gas	Gas
Panthera Hybrid	Electric	Electric + Gas
Sugar Volt	Electric + Gas	Electric or Gas (mission dependant)
Piper Cherokee (planned)	Electric + Gas	Gas

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Piper Cherokee example

Plane	PA-28-140 Cruiser	PA-32-300 Six
Crew	1	1
Passengers	3	5 or 6
Range [nm]	455	774
Ceiling [m]	3,340	5,200
Cruise Speed [Km/h]	200	272
Top speed [Km/h]	230	290
Empty Weight [Kg]	554	811
MTOW [Kg]	975	1542
Assumed pilot weight [Kg]	120	120
Useful load (gas not included) [Kg]	301	611
Engine	Lycoming O-320-E2A	Lycoming IO-540-K1A5
Power [kW]	113	225
Power loading [Kg/hp]	6.5	5.1
Wing loading [Kg/m^2]	65.4	95.2
Fuel tanks [L]	136.3	318
Fuel burn rate cruise [L/h]	75% power: 32 65% power: 28	75% power: 62 65% power: 53

PA-28-140 Cruiser

PA-32-300 Six

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Piper Cherokee example

PA-32

Removable fuel tanks in wings. Extra 50 gallons, or 189 liters.
Without reserve tanks: 129 liters of usable fuel.

Gives us at least two hours of fuel at the 75% thrust burn rate of 62 liters per hour.
Useful load of 611 kg falls to 482 kg.

This is the limit weight we will be using now when determining the best few options for batteries and electric motors.

Best Case

EMRAX 228 engine: 12 Kg. and 50KW (PA-32 needs 225 KW)
LiSOCl2: 500-700Wh/kg becomes 241-337.4KWh,

Assuming no losses two of these engines could run ~ 3hr.
Four engines for 1.5 hrs

PA-32 disposition of extra fuel tanks

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Overarching schedule for the semester

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Detailed schedule for the semester

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Questions?

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Backup Slides

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Constraint Analysis Equations

Takeoff

Maximum Speed

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Constraint Analysis Equations

Landing

Ceiling

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Constraint Analysis Equations

Rate of Climb

Turns

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Sizing Analysis Equations

Climb

Best Range Cruise

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Battery Suggestions

Today’s battery energy density average: 60480 J/N

Battery	Chemistry	Energy Density (J/N)	Cells Needed	Battery Weight
Kokam 460 Series	Li-Ion	68257	175 x
Amicell Li-Po Cells	Li-Po	78609	241 x
Amicell LiSO2 Cells	LiSO2	120612	189 x