aileron spars, smaller fasteners, lighter push-pulls on the
ailerons and rudder, and lighter wing struts. He drilled
holes “in anything that made sense,” and he replaced
the engine instruments and throttle with an integrated
throttle panel that’s part of Yuneec’s motor system. That
panel has four functions: start, stop, throttle, and cruise,
with circuitry to extend battery life. Its 128-by- 64 pixel
LCD shows voltage, current, throttle position, time, and
motor/controller temperature, and it includes alarms for
motor temperature and low battery.
Then he added the rest of the motor system—the motor,
the controller, the batteries, and the charger. The motor
is a direct-drive brushless motor operating at 66. 6 volts,
and it includes an integral motor fan for cooling. The
controller, mounted on the e-Spyder above the batteries,
modulates the power to the engine and has special
circuitry to prolong battery life. It includes a five-second
initial-start operation, along with an automatic cutoff
when battery voltage falls below 59 volts. The lithium-polymer batteries provide between 59 and 75 volts and
40 minutes of operating time, and each produces 30
amp-hours and consists of 54 cells. The charger provides
balanced charging to each cell and shuts down charging
upon fault detection. It uses 230-volt AC input and
includes a 2-by- 4.5-inch data display. Currently, charging
takes three hours per battery, although a one-hour fast
charger is under development.
Peghiny completed the 253-pound e-Spyder in the nick
of time. “Flights nine through 12 were made at Oshkosh,”
he says.
The motor’s controller, (the black box above, with red and blue
wires), monitors the battery cells and power output.
The handset for controlling the
Yuneec electric motor is mounted on
the side of the e-Spyder’s airframe.
The top button on the left is the
on/off switch. Below that are the
disengage (orange) and engage
buttons (green) for the propeller.
The LCD shows: Voltage, amps, rpm,
running time, temperature of the
motor and the actual controller. The
gray slider is the “throttle,” though
Tom says that’s not exactly the correct term. “We need a better
term to describe this function on electric motors.”
IMPROVING THE DESIGN
As a proof of concept, the e-Spyder fulfilled its mission. It
flies at 50 mph and stalls at 25 mph. Response has been
positive, too—the YouTube video of the e-Spyder’s first
flight was viewed more than 14,000 times the first week
it was posted.
Peghiny wants several
enhancements on the next
version ... He envisions
using a new airfoil and
extending the wingspan
from 30 to 33 feet.
Still, Peghiny wants several enhancements on the
next version. He plans to increase the engine-off lift-to-drag ratio from the current 8-to- 1 to 10-to- 1 for a
more robust climb and longer endurance. He envisions
using a new airfoil and extending the wingspan from
30 to 33 feet. He would also create more streamlined
housings for the batteries and controller and enclose
the aft fuselage, and he would seek an exception to
the FAR- 103 empty-weight regulations. With a “fuel
allowance” of an extra 30 pounds, the e-Spyder could
carry one more battery, increasing the flying time
under power to 60 minutes.
Peghiny also wants to evaluate the lifespan of the
aircraft’s batteries. Yuneec says they’re good for 600
cycles, which works out to 400 hours operating time
for two batteries or 600 hours with the three-battery
configuration. Based on the $20,000 price estimate for
the six batteries used in the Yuneec e430 light-sport
aircraft, the operating cost, including reserves, for the
e-Spyder works out to approximately $16.50 per hour
of battery operation, assuming prices remain constant.
The offsetting factor is the fact that maintenance on an
electric motor is considerably simpler than on a piston
engine. The primary maintenance items in the electric
motor are the bearings, which need to be replaced
perhaps every 2,000 hours. The operation reportedly
takes about an hour.
Before the end of the year, Peghiny plans to decide
whether to offer e-Spyder kits for sale. He is currently
evaluating propellers, design improvements, and the
market. “There is a recent addition of a 115-kilogram
(254-pound) class in Europe, which may make the whole
electric ultralight concept more viable,” he says. If he
decides to proceed with the project, he estimates the cost
for a complete, ready-to-assemble kit at between $24,000
and $25,000.
Peghiny says it’s too early to promise anything,
but his eyes light up when he talks of the current
program and the possibility of being in on the early
stages of electric-flight technology. He believes he’s
on the forefront of something new and exciting.
“When I was a kid, dreaming of flying out of the
front door of my mom’s house, it didn’t sound like a
piston engine.”
