Many World War II aircraft are closer than you think.
World War II witnessed technological leaps in aircraft design and performance that recast the nature of air warfare. Wood-and-fabric biplanes were replaced with streamlined, all-metal aircraft. Remote-control guns and pressurized cabins brought forth flying fortresses. Engines became more sophisticated and more powerful, enabling fighter pilots to perform maneuvers that would have been impossible less than a decade earlier.
The National Air and Space Museum’s collection of World War II-era aircraft ranges from propeller-driven trainers, fighters, flying boats, and bombers to the first generation of jet-powered fighters. Visitors to the Museum in Washington, D.C., and to its second location, the Steven F. Udvar-Hazy Center in Chantilly, Virginia, have had the opportunity to view such memorable aircraft as the North American P-51 Mustang, the Grumman F4F Wildcat, and the Douglas SBD Dauntless.
Some of these remarkable aircraft might be closer to you than you realize. Through collaborations with affiliate organizations, the Smithsonian sponsors traveling exhibits and shares artifacts with museums throughout the U.S. and abroad. We’re showcasing seven of these airplanes—including some flown by Germany and Japan—in this issue of Air & Space Quarterly. We recommend, though, that you check with your local museums to confirm these aircraft are currently on display before you and your family begin your own expedition of discovery.
Vought V-173 “Flying Pancake”
Frontiers of Flight Museum in Dallas, Texas
The push to achieve air superiority through innovation yielded some unusual designs during World War II, including the German Horten Ho 229 (a jet-powered, all-wing fighter), the British Hafner Rotabuggy (literally, a flying jeep), and, in the United States, the Vought V-173, more popularly known as the “Flying Pancake.”
The V-173 featured an all-wing design, with its disk-like body serving as the lifting surface. The 16.5-foot-diameter wood propellers were so enormous that the aircraft rested at a 22-degree-upward angle. The idea came from Charles Zimmerman, an aeronautical engineer at the National Advisory Committee for Aeronautics—the predecessor of NASA.
Zimmerman’s design offered unusual benefits. “By having the propellers so very large and spinning at not-inconsiderable velocities as well, you wind up with very large gyroscopic forces,” explained Al Bowers, the former chief scientist at NASA’s Armstrong Flight Research Center in California, in a previous interview with Air & Space/Smithsonian magazine. “So it starts to actually behave a bit more like a helicopter, or in a modern sort of parlance, a V-22 Osprey. V-22 guys would totally relate to the way this particular aircraft operates.” As such, Zimmerman’s design could achieve a zero-roll takeoff with a 30-mph headwind. In essence, it could have levitated from the deck of a moving ship.
Zimmerman turned to private industry to develop the concept further and joined United’s Chance Vought Aircraft Division. Although noted for its conservative approach to aircraft development, Vought built and tested a quarter-scale model of Zimmerman’s design, eventually persuading the U.S. Navy to issue a contract for one V-173 on May 4, 1940.
After 131 hours of flying time, pilots gave the Flying Pancake high marks, noting that, although it had unusual control responses, it could almost hover. “I was able to apply full power, raise the nose as high as it could be held, and have control about all three axes without stalling,” said Boone Guyton, Vought’s chief experimental pilot.
The Navy, however, cancelled the project because of its decision to switch to turbojet engines.
The National Air and Space Museum accepted the aircraft from the U. S. Navy Bureau of Weapons in 1960. In 2004, the V-173 was loaned to the Vought Aircraft Heritage Foundation, where retired Vought employees spent eight years restoring it. The V-173 was then put on display at the Frontiers of Flight Museum—a Smithsonian affiliate that has more than 200 models of World War II aircraft.
The last existing Ki-43-IIb was loaned to the Pima Air & Space Museum in 2008.
Ki-43 Hayabusa (Peregrine Falcon)
Pima Air & Space Museum in Tucson, Arizona
The Nakajima Aircraft Company aptly named the Ki-43 after the Peregrine Falcon (Hayabusa), a bird of prey widely known as a graceful, speedy hunter. The fighter surprised western pilots when they first encountered it because Allied intelligence specialists underestimated the capabilities of Japan’s aircraft industry. Although not as well-known as the Mitsubishi A6M Zero, the Ki-43 was a formidable aircraft, particularly during the early war years. After Allied pilots tangled with Hayabusas in both the China-Burma-India and South-West Pacific Theaters, intelligence teams codenamed the airplane Oscar.
The Ki-43 began as a set of specifications that the Japanese Imperial Army issued to the Nakajima Aircraft Company in 1937. The army needed to replace the nimble Nakajima Ki-27, an open-cockpit fighter, with an aircraft that had more speed (311 mph), better time to climb (16,405 feet in five minutes), and a range of 800 miles. A team led by Hideo Itokawa took only a year to roll out the first prototype. Flight tests began in January 1939. A 925-horsepower engine was selected to power the prototypes.
Although not as well-known as Japan’s A6M Zero, the Ki-43 was a formidable aircraft, particularly during the early war years.
The new fighter flew well, but army test pilots criticized its maneuverability and, for a time, it seemed that Nakajima would abandon the Ki-43. However, the firm decided to salvage the design. Engineers replaced the single-stage supercharger with a two-stage unit to provide greater power at higher altitudes. The most significant change was the addition of combat flaps beneath the wing center section. When the pilot deployed these tapered flaps at speed, they lowered the stall speed, increased lift, and the turning circle of the Ki-43 shrank dramatically.
Test pilots were highly impressed by the modifications, prompting the army to order the Ki-43 into production.
Like many Japanese combat aircraft of World War II, the first Ki-43s lacked protective armor for the pilot and self-sealing fuel tanks. When the firm introduced the Ki-43-II in 1942, Nakajima addressed both shortcomings and incorporated other minor refinements. Engineers also designed other variants including the Ki-43-IIb, which featured a major revision to the oil cooler. In previous models, two radiators cooled the oil. One unit lay inside the cowling ahead of the engine and the other fit around the propeller shaft behind the spinner. In the Ki-43-IIb, a single cooler was placed inside the carburetor duct, after the duct was enlarged to accommodate the new component.
In all, more than 5,900 Hayabusas fought in the skies above China, Burma, India, the Malay Peninsula, New Guinea, the Philippines, many other South Pacific islands, and the Japanese home islands.
In 2008, the National Air and Space Museum loaned this last existing Ki-43-IIb to the Pima Air & Space Museum in Arizona, which is one of the world’s largest non-government funded aerospace museums. The museum is home to nearly 400 historic aircraft, including three other World War II-era aircraft on loan from the Smithsonian: the Nakajima Ki-115a, the Kugisho MXY7-K2, and the Martin PBM-5A Mariner.
The Piper L-4B Grasshopper—seen here flying over an M3 Stuart tank—often flew artillery-spotting missions.
Piper L-4B
Oklahoma National Guard Museum in Oklahoma City
“The Versatile Weapon!” declared a 1943 advertisement for the Piper L-4B. “Their economy of operation, amazing maneuverability, and rugged construction perfectly adapt Piper planes for the rigorous and varied parts that they are playing, and will play, in this great battle for democracy!”
The Pentagon apparently agreed. Between 1941‑45, the U.S. Army Air Forces procured almost 6,000 Piper aircraft. During World War II, the L-4 and its variants—nicknamed the “Grasshopper”—sometimes served as flying ambulances and performed duties including artillery spotting, pilot training, courier service, and front-line liaison.
An estimated 980 L4-B variants were built. Many pilots had trained on the civilian version, the J-3 Cub, before entering the military.
The Grasshopper was a military version of Piper’s beloved J-3 Cub—mechanically identical, except for the additions of a plexiglas greenhouse skylight and rear windows to improve pilot visibility. First built in 1937, the Piper J-3 earned its fame as a trainer. The emergence of the Civilian Pilot Training Program immediately before the U.S. entered World War II spurred sales of the J-3. In 1940, 3,016 Cubs were manufactured and, at the wartime peak, a new J-3 emerged from the factory every 20 minutes. Some 75 percent of all pilots in the Civilian Pilot Training Program were trained on Cubs, many going on to more advanced training in the military.
An estimated 980 L-4B variants (which didn’t have radio equipment) were built. One of them was transferred to the National Air and Space Museum by the U.S. Air Force and is currently on loan to the Oklahoma National Guard Museum in Oklahoma City. Previously called the 45th Infantry Division Museum, the destination is well-known for its 15-acre Thunderbird Park, where more than 60 military vehicles, tanks, aircraft, and big guns are displayed.
A distinctive feature of the Fw-190D-9 was its long nose, which had been extended to accommodate a larger engine.
Focke-Wulf-190D
National Museum of the United States Air Force in Dayton, Ohio.
The Focke-Wulf-190D interceptor was considered by many German pilots to be the finest piston-powered fighter in the Luftwaffe. The aircraft was a variant of the Fw-190A, which first appeared in action over northwestern France in 1941, where it had proved its superiority over Britain’s top fighter, the Supermarine Mk V Spitfire. In late 1943, designers replaced the aircraft’s air-cooled BMW 801-series engine with the more powerful liquid-cooled Junkers Jumo 213 engine that previously had been used exclusively on bombers.
Capable of flying 430 mph at 20,200 feet, the improved performance of the 190D made the aircraft an effective interceptor against the burgeoning fighter-escorted Allied bomber formations. With its robust armaments—two 20mm Mauser MG-151/20 cannon in the wing and two 13mm Rheinmetall MG-131 cannon over the engine—German pilots considered it more than a match for the P-51D Mustang. The D9 variant that entered service in 1944 was even faster than the D1, capable of flying 440 mph at 37,000 feet. Because the larger engine lengthened its nose, a 20-inch section had to be added to the fuselage just forward of the tail. Allied and Luftwaffe pilots immediately dubbed the D9 the “long-nose” (langnasen).
A view from inside the cockpit of the Fw-190, which proved itself to be an effective interceptor against fighter-escorted Allied bombing formations.
But as the war progressed and the U.S. Army Air Forces began hitting aircraft assembly plants and oil refineries, Germany’s fighter force steadily lost effectiveness against daylight bombing raids. By the time the Luftwaffe fighter group JG-6 received 150 D9s in April 1945, only four aircraft could fly at a time.
Over the course of the war, approximately 13,250 fighters and 6,250 fighter-bomber versions of the Fw-190 were manufactured for the Luftwaffe. At least 11 Fw-190s still exist in museums worldwide—four of these are Fw-190Ds, all of which are in the United States.
One of them was donated to the National Air and Space Museum by the U.S. Air Force on June 15, 1960. Since 1975, the Fw-190D has been on loan to the National Museum of the United States Air Force Museum at Wright-Patterson Air Force Base in Dayton, Ohio. Last year, the museum celebrated its 100th anniversary. It has more than 360 aircraft and missiles on display.
The Air Zoo Aerospace and Science Museum put the XP-55 on display in 2006, following extensive restoration work.
XP-55 Ascender
The Air Zoo Aerospace and Science Museum in Kalamazoo, Michigan.
Less than two years before the United States declared war on the Japanese in 1941, the U.S. Army Air Corps sponsored three radical fighter aircraft designs. All of them had pusher configurations—the propellers are placed behind the engines—which offered some advantages over the conventional tractor configuration (the propellers are in front of the engine) such as enhanced pilot visibility and the option to concentrate most of the guns in the nose of the aircraft.
But the similarities between the three fighter concepts ended there. Vultee proposed a twin-boom pusher, the XP-54, and Northrop championed a bobbed-tail flying wing known as the XP-56 Black Bullet. Curtiss-Wright engineers swerved even further from convention: They stuck the engine behind the pilot, mounted a short canard near the nose, and placed two vertical tails at the end of swept wings. The aircraft was designated the XP-55 Ascender (otherwise known as the “Ass-Ender,” in recognition of its backward configuration). Engineers also added a revolutionary propeller jettison system to ensure that the pilot wouldn’t smack into the spinning rear propeller in the event of a bailout. A cluster of four .50-caliber machine guns were fitted into the nose assembly.
Test pilots and engineers judged the Ascender’s performance too poor for an effective combat fighter, but it did demonstrate where future trends in fighter design should not go.
But the XP-55, despite multiple modifications during flight testing, was a failure. The aircraft had a tendency to stall without warning, and it was slow compared to most fighters already in production. Only three XP-55s were ever made. Two of them were destroyed upon crashing. The last remaining prototype was stored at the National Air and Space Museum’s Paul E. Garber Facility in Suitland, Maryland, until it was loaned to the Air Zoo Aerospace and Science Museum in 2001 for restoration and display.
The Air Zoo—which is an affiliate of the Smithsonian Institution—was originally named the Kalamazoo Aviation History Museum when it was founded in 1977. The name was changed in 1999 in recognition of the many airplanes in its collection that have animal nicknames: Gooneybird, Wildcat, and Tigercat, among others. With more than 100 airplanes and spacecraft, Air Zoo is one of the 10 largest nongovernmental aviation museums in the U.S.
The Air Zoo has also become known for undertaking some challenging restoration projects, including a Douglas SBD Dauntless that had been retrieved from the bottom of Lake Michigan and a Waco CG-4A cargo glider that had been rusting in the Michigan woods (it had been used as a makeshift hunting or fishing shed). Compared to those aircraft, the XP-55 was in much better shape. The restoration staff even discovered notes in the airplane’s interior written by the original technicians to remind themselves of the work they had done on it.
The restored XP-55 was unveiled and put on display in 2006.
Martin PBM-5A Mariner
Pima Air & Space Museum in Tucson, Arizona
One of the most successful patrol aircraft of World War II is the PBM (Patrol Bomber, Martin) Mariner. By the end of the war, the Mariner had proven itself even more versatile and capable than its legendary contemporary, the Consolidated PBY Catalina.
The patrol bomber was manufactured by the Glenn L. Martin Aircraft Company, which incorporated several design elements that made it perform better than the PBY, including a deep hull mounting a gull wing, which kept the vulnerable engines out of the salt spray without the use of the Catalina’s parasol wing and its external bracing. An internal bomb bay enabled higher speeds when the aircraft was loaded with ordnance. And the wing floats could retract into wing bays to reduce drag.
The PBM went into service as a patrol aircraft that could not only locate enemy shipping, but also attack it with a 4,000-pound bomb load (or torpedoes in later versions). The aircraft, with its crew of nine, was armed with .50-caliber machine guns individually mounted in the nose and dorsal turrets, as well as in the waist gimbals and tail position.
The massive aircraft proved their value in combat during the Battle of the Atlantic, during which they operated out of bases located in the western Atlantic, ranging from Bermuda to Brazil. Of the 29 submarines sunk by U.S. patrol aircraft during World War II, 10 were by PBMs.
A later version, the PBM-3, spawned a series of variants for specialized missions, including the PBM-3C, which mounted a powerful APS 15 radar and dual .50-caliber machine guns in its three turrets. The PBM-3R transport version, which had its armor and armament removed, supplied distant submarine bases and flew medical evacuation missions.
A PBM-5A George-2 was deployed to locate survivors of an airplane crash in Antarctica, made during an attempt to establish a research base in 1946.
In 1944, the final version, the PBM-5, entered service. One of its most innovative features was the provision for jet-assisted take-off rockets, which enabled much steeper climb angles. These were ideal for making short takeoffs in the fraught ocean conditions often encountered on rescue missions flown for B-29 crews that had to bail out or ditch their bombers.
Only one of the 1,366 Mariners constructed survives intact to the present-day. In 1953, it was retired with 1,326 flight hours and then sold as government surplus to civilian owners before it was donated to the National Air and Space Museum in 1973. The aircraft is on loan and displayed at the Pima Air & Space Museum in Tucson, Arizona.
A6M7 Reisen (Zero)
San Diego Air & Space Museum, California
No other aircraft surpasses the Mitsubishi A6M Reisen (Japanese for Zero Fighter, pronounced “ree-sin,”) as the symbol of Japanese air power during World War II. Nearly 10,500 were manufactured between March 1939 and August 1945—more than any other Japanese aircraft.
Design work on the Reisen began in 1937, when the Japanese navy staff directed the Mitsubishi and Nakajima aircraft companies to submit proposals for a new aircraft to replace the Mitsubishi A5M carrier fighter. Mitsubishi designer Jiro Horikoshi and his team focused on reducing airframe weight as much as possible and used a newly developed aluminum alloy. They also eliminated armor plating and self-sealing fuel tanks. These protective devices weighed hundreds of pounds and could not be incorporated into the aircraft if Mitsubishi hoped to meet the performance requirements specified by the navy. The compromise made the Zero a formidable fighter, but these vulnerabilities would contribute to its undoing.
Since the Reisen was considerably lighter than U.S. fighters, it could climb faster and out-maneuver them. However, as combat experience mounted and training improved, U.S. Navy and Army pilots learned to adapt: They would make a single, straight pass with guns blazing and then continue away from the Zero using superior speed to zoom to safety or circle around at a distance and attack again. Such tactics transformed the Grumman F4F Wildcat (once considered obsolete against the Zero) into a daunting opponent.
Still, the Zero and its variants remained in production throughout the war. By late 1944, following tremendous defeats at Midway, the Philippine Sea, and Leyte Gulf, Japan’s large-deck carrier fleet was almost destroyed. Dive bombers that could operate from small flight decks were urgently needed. When the Navy directed Mitsubishi to redesign the Zero to drop bombs, the A6M7 was born. The centerline fuel tank was replaced with a bomb rack that carried a single 551-pound bomb. The horizontal stabilizer was reinforced to withstand the stress of pulling out from a steep dive.
The National Air and Space Museum acquired its A6M7 in 1962 and transferred it to the to the San Diego Aerospace Museum (now called the San Diego Air & Space Museum) in 1981, where a volunteer crew spent more than 8,500 hours over a three-year period restoring the airplane. It currently remains on exhibit in San Diego.
This article is from the Spring 2024 issue of Air & Space Quarterly, the National Air and Space Museum's signature magazine that explores topics in aviation and space, from the earliest moments of flight to today. Explore the full issue.
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