Open Source Soaring
We may all dream of flying silently through the
clouds, but Mike Sandlin has actually created a
set of gliders that allow you to fly with only the
power of gravity.
Using his expertise in building hang gliders,
Sandlin prototyped a slow-flying, ultralight sailplane
that he calls an “airchair.” Airchairs are basically
hang gliders with seats, that steer like an airplane.
Beginning with his Basic Ultralight Glider (Bug) in
the 1990s, Sandlin has pioneered a unique field of
powerless aviation.
Photograph by Floyd Fronius
His airchairs include the biplane Bug series,
monoplane Goat series, and his current creation, the
rudder-steered Pig series. Instead of selling plans
like most small aircraft designers, Sandlin provides
the source CAD drawings free for download.
The airchair is designed to be loaded on top of
a car for quick setup and disassembly. The pilot
launches the glider by rolling down a small incline,
usually at hang-glider launch sites.
Sandlin says his gliders are “intended to provide
open air soaring, forgiving flight characteristics,
convenient transport, simple ‘garage technology’
construction, and a high level of crash safety,” all
major accomplishments for machines that weigh
less than 155 pounds.
The Pig (Primary Instruction Glider) is a biplane
design that features a two-axis control system,
which is much easier for beginner pilots. It’s slow,
but easy to fly, while still maintaining a decent level
of safety for the pilot. Assembly can be accomplished in less than an hour with minimal tools.
Although Sandlin prefers to avoid working with
motors, his design has incorporated a space for a
small pusher motor attachment on the Pig. With a
small motor, the Pig could hop between thermals,
staying airborne for hours on end.
So, when will Pigs fly? As it happens, they’re flying right now, and with Sandlin’s help, you could fly
a Pig of your own!
—Abe Connally and Josie Moores
>> Basic Ultralight Gliders: makezine.com/go/glider
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