18 March 2019 _ PopularMechanics.com
L
ATE LAST YEAR, an airplane
weighing five pounds, with the
wingspan of an albatross, flew the
180-foot leng th of MIT’s duPont
Athletic Center gym.
It had no moving parts.
Instead of propellers or a
jet engine, the plane developed airf low
and lift with electricity. Wires mounted
in front of the wings contain positive
electrodes, and the wings contain negative
electrodes. A strong positive charge sends
ions flow ing back toward the w ings. In the
process, they bump into air molecules,
creating wind—in this case, reaching 200
mph—that flows over the airfoil-shaped
wings. (See illustration below.)
According to Steven Barrett, the
associate professor of aeronautics and
astronautics who led the team that built
the plane, this phenomenon—called ionic
wind—has been known since at least the
1920s but never refined for practical
applications. And using it for flight had
its own distinct challenges, like producing
it with equipment small and light enough
to fit on a fuselage. “We need a light-
weight power converter to create the high
voltages necessary—40,000 volts,” says
Barrett. “And you know, last time people
were interested in this stuff, in the 1960s,
that was only a few years after transistors
were invented. It was not possible to create
a lightweight power converter then.”
Miniaturizing the power converter
was the biggest challenge to building the
plane, but Barrett imagines that in the
longer term, finding batteries with energy
densities high enough that they can be
small enough to fly will be the main dif-
ficulty (as with seemingly every form of
electric transit). “Once we get to the point
where the battery is the constraint, that’s
sort of success in a way, because we’ve put
aside the other problems with the tech-
nolog y,” he says.
So the plane is far from taking on heavy
payloads, and even further from Barrett’s
dream of manned flight. (He was inspired
by the sleek, silent craft in sci-fi classics
like Star Trek.) But in the near term, ionic
wind systems could be installed on the
skin of existing jets and used to smooth
airf low at their tails, where turbulence
creates drag and hinders fuel efficiency.
And even at a low payload capacity, the
solid-state plane could start replacing
drones. Not so much quadcopters, whose
f light characteristics are more akin to
helicopters than airplanes, but winged,
horizontal drones. Barrett imagines
high-flying solar-powered surveillance
missions: Because an ionic wind system
lacks moving parts, it needs almost no
maintenance—a spy drone so powered
could stay in the air indefinitely.
with No Moving Parts
An aircraft rides on wind it makes itself from electrical
potential, pointing the way to a newform of aviation.
/ BY SAM BLUM /
borderline crackpots have
been puzzling over ionic
wind for centuries. Here, a
selection of key happenings.
1750 The Electric Fly
British scientists construct
a pinwheel-like device that
turns when charged, thanks—
unbeknownst to them—to ion
flow. Leading thinkers debate
the cause for centuries.
1929 How I Control Gravitation
Thomas Townsend Brown
publishes “How I Control
Gravitation” about ion wind,
which he interprets as an
interaction between elec-
tricity and gravity. The article
contains grandiose claims
about rounding out Einstein’s
theory of relativity.
1964 The Ionocraft
Popular Mechanics
publishes a story on
Major de Seversky’s
Ionocraft, which
we describe as “the
incredible magic
carpet of the future.”
It goes up and down,
and that’s about it.
2012 Ionic Cooling
Apple is granted a patent for
a method to use an ionic wind
system to cool its devices. Why
no one had done it before: Ionic
wind only flows in a straight
line. Apple’s solution: magnetic
deflectors. Super cool, but so
far not used in any production
Apple products.
2017 Ionic Wind for Foodies
Scientists from Indonesia test
the possibility of using ionic
wind to dry slices of wild ginger,
a local root used in herbal
medicine (not the same ginger
we know). Bonus feature:
The electrical discharge kills
microbes on the plant.
Ions Air Molecules
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