Electric Gliders - Nadler

Electric G

Dave Nadler “YO Ele
Robert Mudd

SSA 2012 Convention

Gliders

ectric”

Slide 1

Why Power a Glid

• The Promise of Freedo

From Tows, Landouts,

• Motor Penalties:

• Weight
• Cost and Complexity a
• Decision Altitudes High

Plan for motor out and

• Compromises for Diffe
• Touring Motorgliders v

(electrics are not for To

SSA 2012 Convention Electric Gliders ©

der ?

om !
, Crews…

and Maintenance

her (stop Soaring to Land):
not running situation

erent Missions

vs. Performance MGs
ouring)

© Dave Nadler "YO“ 2012 Slide 2

Why Electric ? Ga

• Reliability (* Jonas De Rese P

• Both for the self-launch

engines, 30 % of the pi
failure after having perf
run at the beginning of

• 30 % of the pilots indic

damage was done to th
having and operating a

• Operational and Mainte

• Air-start time, difficulty,

• Vibration, noise, heat, f

SSA 2012 Convention Electric Gliders ©

as Problems...

PhD thesis at Delft University)

hing and sustainer
ilots have had an engine
formed a successful test
the flight.

cate that some kind of
he aircraft as a result of
an engine.

enance Difficulties:

, sink rate prior starting

fuel, drive belts, etc.

© Dave Nadler "YO“ 2012 Slide 3

Electric Advantag

• Reliable – electric mot

Safety still precludes a

• Fast air-start (Antares
• Typically automated sy
• Low sink rate “engine o

(no cooling radiator) –

• Low vibration and heat
• Negligible density altitu
• Plenty of disadvantage

SSA 2012 Convention Electric Gliders ©

ges

tors usually start !
air-start without field.
~ 10 seconds)
ystems - easy
out not running”

lower decision height
t – low maintenance
ude effect
es too !

© Dave Nadler "YO“ 2012 Slide 4

Electric Power Iss

● Every battery is a trade-off:

● Energy density
● Cost
● Lifetime – Cycles, years
● Max discharge current
● Weight
● Safety
● Memory effects
● Temperature requirements

● Battery Care and Feeding:
Balancing, heating, cooling
Significant complexity & cost.

SSA 2012 Convention Electric Gliders ©

sue: Batteries

© Dave Nadler "YO“ 2012 Slide 5

Energy Density of

• Gasoline: 13 Kw*hr/lb,

gas/electric drive (.93/.
~ 2 kw*hr/lb effective e

• SAFT Lion 300 w*hr/lb

around 1/7th effective

• Nissan Leaf battery ab

Kokam Lion about 90%

• Electric motor weight m

• Experimental batteries

Not yet real...

SSA 2012 Convention Electric Gliders ©

f Batteries

, relative efficiency of
.15) or equivalent:
energy

b as used in Antares*,
energy/weight of gas

bout the same,
%.

makes up only a bit...

s heading > 1kw*hr/lb

© Dave Nadler "YO“ 2012 Slide 6

Enough Math: Glid

• The energy you need to c

weight; same for sustaine

• After you start a gas susta

long time climbing to get h
crossing the woods home

• Level flight takes much le
• Battery is ~2/3 of e-propu
• Why make a e-sustainer ?

energy for a climb ! A pow
inexpensive. If you're goin
batteries, might as well m

SSA 2012 Convention Electric Gliders ©

der Issues

climb depends on aircraft
er or SL.

ainer, you may spend a
high enough before
e.

ess power than climb

ulsion weight & cost

? Batteries need enough
werful electric motor is
ng to spend weight/cost for
make a self-launch.

© Dave Nadler "YO“ 2012 Slide 7

Real Performance

• Distance in level flight

With full charge, and y

• Cruise range specifie
Antares 20E example

• You're low in the boo
Climb 3000 ft using ~
then cruise 70nm saw

• Published numbers a
charge (ie took a tow

• So far, no electrics for

self-launch+reserve or

SSA 2012 Convention Electric Gliders ©

e

specs sound great, But
you will need to climb...

ed as level / sawtooth
e 76 / 103 nm

ondocks:
~1/3 of battery power,
wtooth using ~2/3 battery.

assume you had a full-
w to launch)

long-distance cruising:
r sustainer only !

© Dave Nadler "YO“ 2012 Slide 8

Lange Antares 20E

• High-end of glider perf

• Antares 20E: 56:1 Ma
Typical 9000+ foot clim

• Antares 23E: 60:1 at 7
Higher weight, lower c

• >70 delivered (> total o

SSA 2012 Convention Electric Gliders ©

E and 23E

formance and cost

ax L/D, >800 fpm climb-rate
mb, >7500 at max gross
78 knots, ultimate for WGC
climb altitude and rate

of all other electrics)

© Dave Nadler "YO“ 2012 Slide 9

Taurus Electro 15

• Compared to pure glid

50% to price.

• With recommended op

– 50 lbs heavier than g
– Stated climb 6500 ft,

• Big cockpit, easy to tax

SSA 2012 Convention Electric Gliders ©

5m Side-by-Side

der, gas or electric adds

ptional larger battery:

gas-powered
, or cruise ~ 1 hour

xi

© Dave Nadler "YO“ 2012 Slide 10

FES Configuration

• Simpler than pylon, ret
• No pylon drag engine n
• Drawbacks: Drag from

disturbed flow on fusel

• Retrofit Issues – Mayb

• Weight of non-lifting

• Structural complexity

• Possibly a good solutio

performance sailplane
Currently available on

SSA 2012 Convention Electric Gliders ©

n

trofit existing planes ?

not running, instant on

m prop (prop plus
lage), prop diameter

be not...

parts may preclude retrofit

y (batt), Round nose

on for moderate
es.

LAK-17B and Silent.

© Dave Nadler "YO“ 2012 Slide 11

Alisport Silent Ele

• Nose-mounted propell
• Compared to unpower

– 50% more expensive
trailer, instruments, a

– 25% heavier (160kg-

• Climb 5900 ft, or cruise

SSA 2012 Convention Electric Gliders ©

ectro (LAK FES)

ler 13.5m self-launch
red glider, about:

e (less difference after
and options)
-205kg electric-190kg gas)

e 80 nm

© Dave Nadler "YO“ 2012 Slide 12

LAK-17B FES

• Contemporary 15/18-m
• Climb 3600 ft, or cruise
• Only adds 80 lbs over
• See the LAK-17B in th

SSA 2012 Convention Electric Gliders ©

meter glider
e 62 nm
pure sailplane !
he exhibit hall

© Dave Nadler "YO“ 2012 Slide 13

Who Knows This G

SSA 2012 Convention Electric Gliders ©

Glider ?

© Dave Nadler "YO“ 2012 Slide 14

Have Aliens Invad

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ded ?

© Dave Nadler "YO“ 2012 Slide 15

Who Knows This G

SSA 2012 Convention Electric Gliders ©

Glider ?

© Dave Nadler "YO“ 2012 Slide 16

What happened he

SSA 2012 Convention Electric Gliders ©

ere ?

© Dave Nadler "YO“ 2012 Slide 17

6000 km range ?

SSA 2012 Convention Electric Gliders ©

© Dave Nadler "YO“ 2012 Slide 18

Who Knows This O

SSA 2012 Convention Electric Gliders ©

One ?

© Dave Nadler "YO“ 2012 Slide 19

Questions To Ask

• Climb altitude at your w
• Cruise range sawtooth
• Battery lifetime ?
• Measured performance
• Make sure range meet
• Number planes deliver
• Flight Trial available ?
• Customer references

SSA 2012 Convention Electric Gliders ©

k before buying...

weight ?
h and level ?

e, power & glide ?
ts your needs !
red to customers ?

© Dave Nadler "YO“ 2012 Slide 20

A List of Electric G

• Eric Raymond's SunSe
• Lange Antares 20E an

Schempp-Hirth Arcus E

• Pipstrel Taurus electro
• Silent electric (original
• LAK 17B FES
• Waiex E
• Experimentals: Pipistre

Solar Impulse, Lange H

SSA 2012 Convention Electric Gliders ©

Gliders

eeker, SunSeeker II
nd 23E,
E
o G2, Apis E

and FES)

el G4, Icaré II, eGenius,
H2 and H3, Lazair E

© Dave Nadler "YO“ 2012 Slide 21