By fooling around with a wind tunnel in the 1940s, German engineers discovered pivoting an airplane’s wing made it both faster and more efficient. NASA ran with the concept, and developed the AD-1, a plane that could pivot its wing 60 degrees relative to the fuselage. NASA ran test flights for several years but eventually abandoned the concept because its inherent instability required too many costly engineering fixes. NASA
By fooling around with a wind tunnel in the 1940s, German engineers discovered pivoting an airplane’s wing made it both faster and more efficient. NASA ran with the concept, and developed the AD-1, a plane that could pivot its wing 60 degrees relative to the fuselage. NASA ran test flights for several years but eventually abandoned the concept because its inherent instability required too many costly engineering fixes.
Russian expat Ivan Makhonine designed planes with telescoping wings for the French during WWII. When extended, the MAK-101's wings were more stable, more fuel efficient, and slower. The wing would retract for dogfights and acrobatics. A.S. Yakovlev/NASA
Russian expat Ivan Makhonine designed planes with telescoping wings for the French during WWII. When extended, the MAK-101's wings were more stable, more fuel efficient, and slower. The wing would retract for dogfights and acrobatics.
After they occupied France, the Germans wanted to take a MAK-101 prototype and its telescoping-wing technology back to the motherland. But, wily French resistants sabotaged those plans by crashing the prototype into a field. Photographer Unknown
After they occupied France, the Germans wanted to take a MAK-101 prototype and its telescoping-wing technology back to the motherland. But, wily French resistants sabotaged those plans by crashing the prototype into a field.
The Soviets made some of the kookiest planes, like the IS-1, which could morph from a bi-wing plane to a mono-wing plane. Built in 1938, it used the double-stacked wings to generate a lot of lift during take off, and switched to mono-wing at altitude for speed and maneuverability. Photographer Unknown
The Soviets made some of the kookiest planes, like the IS-1, which could morph from a bi-wing plane to a mono-wing plane. Built in 1938, it used the double-stacked wings to generate a lot of lift during take off, and switched to mono-wing at altitude for speed and maneuverability.
This plan-view diagram shows how the IS-1 deployed its lower wing and landing gear. A.S. Yakovlev/NASA
This plan-view diagram shows how the IS-1 deployed its lower wing and landing gear.
As a jet approaches supersonic speeds, air compressing at the front of the wing causes drag. Engineers figured out that sweeping the wing back can disrupt this drag effect. However, at low speeds this sweep causes air to travel along the wing (from root to tip) instead of over it. This makes jets stall, and stalling makes jets crash. Jets with a mechanically adjustable wing angle, like the F-14, solved this problem. CDR David Baranek/US Navy
As a jet approaches supersonic speeds, air compressing at the front of the wing causes drag. Engineers figured out that sweeping the wing back can disrupt this drag effect. However, at low speeds this sweep causes air to travel along the wing (from root to tip) instead of over it. This makes jets stall, and stalling makes jets crash. Jets with a mechanically adjustable wing angle, like the F-14, solved this problem.
The F-14's Soviet counterpart was the MiG-23. Like the F-14, the MiG's wings would be out for low-speed maneuvers and swept back when it was time to enter the Danger Zone. US Department of Defense
The F-14's Soviet counterpart was the MiG-23. Like the F-14, the MiG's wings would be out for low-speed maneuvers and swept back when it was time to enter the Danger Zone.
In the 1930s, the Soviets experimented with variable chord—the distance between the front and back wing edges. The result was the RK-1, whose retractable wing sheaths completely disappeared into the fuselage, leaving a narrow wing that produced less drag. The whole system was controlled manually from the cockpit with steel cables. Photographer Unknown
In the 1930s, the Soviets experimented with variable chord—the distance between the front and back wing edges. The result was the RK-1, whose retractable wing sheaths completely disappeared into the fuselage, leaving a narrow wing that produced less drag. The whole system was controlled manually from the cockpit with steel cables.
While it isn’t great for cruising, long chord gives a plane leverage to take off at a lower speed and a higher angle. The RK-1 performed well, but as WWII intensified, the Kremlin ordered its designer to work on planes that could keep up with German dogfighters. A.S. Yakovlev/NASA
While it isn’t great for cruising, long chord gives a plane leverage to take off at a lower speed and a higher angle. The RK-1 performed well, but as WWII intensified, the Kremlin ordered its designer to work on planes that could keep up with German dogfighters.
To stay out of range of Soviet missiles, the US developed the XB-70 to fly Mach 3 at an elevation of 70,000 feet. The bomber flew so fast and so high that it had to ride its own shock waves to stay aloft, similar to how a planing boat rides its own bow wake. Rotating wing tips allowed the XB-70 to capture more of the shock wave beneath it, and also made the plane more stable while it was skimming through the Stratosphere. US Air Force
To stay out of range of Soviet missiles, the US developed the XB-70 to fly Mach 3 at an elevation of 70,000 feet. The bomber flew so fast and so high that it had to ride its own shock waves to stay aloft, similar to how a planing boat rides its own bow wake. Rotating wing tips allowed the XB-70 to capture more of the shock wave beneath it, and also made the plane more stable while it was skimming through the Stratosphere.
Today pilots use mechanical wing flaps to control a plane’s pitch and roll. The Wright brothers did the same thing on the very first plane in 1903. Rather than mechanical flaps, they twisted the wing itself with pulleys they controlled by rocking their hips back and forth in a cradle. Wilbur Wright
Today pilots use mechanical wing flaps to control a plane’s pitch and roll. The Wright brothers did the same thing on the very first plane in 1903. Rather than mechanical flaps, they twisted the wing itself with pulleys they controlled by rocking their hips back and forth in a cradle.
NASA, the Air Force and Boeing recently resurrected wing twist with the Active Aeroelastic Wing. Most plane wings can change their leading edge shape to make the airflow more efficient. AAW takes this a step further, with the front edge working to actively twist the wing into a maneuver, for faster, tighter aerial acrobatics. The X-53 was a modified F/A-18 with AAW. Jim Ross/NASA
NASA, the Air Force and Boeing recently resurrected wing twist with the Active Aeroelastic Wing. Most plane wings can change their leading edge shape to make the airflow more efficient. AAW takes this a step further, with the front edge working to actively twist the wing into a maneuver, for faster, tighter aerial acrobatics. The X-53 was a modified F/A-18 with AAW.
AAW morphing is subtle, but powerful. This animation of NASA's X-53 test platform shows how creating a twist using both the front and rear wing edges helps with high-speed maneuvers. The flaps are tough to coordinate, however, and using them can be like trying to steer a car with both sets of wheels. NASA Dryden
AAW morphing is subtle, but powerful. This animation of NASA's X-53 test platform shows how creating a twist using both the front and rear wing edges helps with high-speed maneuvers. The flaps are tough to coordinate, however, and using them can be like trying to steer a car with both sets of wheels.
Take off. Rise. Soar. Bank. Turn. Stall. Swoop. Dive. Land.
For each of the different kinds of flying an airplane has to do, there’s an ideal shape and configuration for its wings. Even though bird-like flappability isn’t feasible with struts and steel, engineers since the dawn of aviation have been trying to make wings that change shape.
Sometimes the morphing seems inevitable, like the wing flaps that most planes use to steer. Other cases, like the airfoils that sweep back to a vee and carry our fighter jets to supersonic speeds, could only have come from trial-and-error arms races. And then there are the oddballs, the telescoping, twisting, torquing shapeshifters.
Any engineer can tell you that solving one challenge often means introducing others, sometimes catastrophic. For every morphing wing design that makes it into the aeronautics canon, there are dozens of others that survive only in footnotes, photographs, or the graveyard.
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