MIT and NASA engineers have shared the design of a completely new kind of airplane wing. The radical wing is made of hundreds of tiny identical pieces. The wing can change shape to control the plane's flight. It’s creators say the efficient design may boost aircraft production, flight, and maintenance efficiency.
The wing was tested in a NASA wind tunnel. Typical wing designs have separate moveable surfaces such as ailerons to control the roll and pitch of the plane. However, the new wing can move the whole wing or just sections to give greater precision control over movement.
Tiny pieces come together to form metamaterial
The wing is comprised of both stiff and flexible components. Each of the individual pieces is made from a polymer material when they have been bolted together the pieces from an open lattice framework.
It is overall much lighter than typical aircraft wings and therefore much more energy efficient. The wings research team describe how the plane is made of ‘thousands of tiny triangles of matchstick-like struts’ which results in a framework of mainly empty space.
Infinite shape possibilities
The combined pieces form a “metamaterial” that is stiff like a polymer but extreme light like an aerogel. Traditional wing designs are a compromise of the best shapes of a wing that are required for each different stage of flight from takeoff to cruising. This new wing design could change shape to be in the optimal design for each stage of the flight.
The wing would self-shift its shape according to the different aerodynamic loading conditions. The passive self-moving wing is only achieved through the very careful placement of struts with different amounts of flexibility or stiffness. This allows the wing to bend in specific ways according to its current state. “We’re able to gain efficiency by matching the shape to the loads at different angles of attack,” says Cramer, the paper’s lead author. “We’re able to produce the exact same behavior you would do actively, but we did it passively.”
Easy to manufacture
While this prototype wing was hand assembled by students future iterations could easily be built by a swarm of small, simple autonomous assembly robots. Each individual piece is made using injection molding and a complex 3D mold.
Each piece resembles a hollow cube made up of matchstick-size struts along each edge. One piece takes just 17 seconds to create. “Now we have a manufacturing method,” he says. While there’s an upfront investment in tooling, once that’s done, “the parts are cheap,” he says. “We have boxes and boxes of them, all the same.”
The resulting wing design might dramatically veer away from the familiar tapered hollow tube too. “You can make any geometry you want,” he says. “The fact that most aircraft are the same shape is because of expense. It’s not always the most efficient shape.”
A paper [PDF] describing the development of the wing appears today in the journal Smart Materials and Structures, co-authored by research engineer Nicholas Cramer at NASA Ames in California; MIT alumnus Kenneth Cheung SM ’07 PhD ’12, now at NASA Ames; Benjamin Jenett, a graduate student in MIT’s Center for Bits and Atoms; and eight others.