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Nakajima Ki-43 Hayabusa in Communist Chinese Service

August 16, 2018Republic of China, WW2China, Cold War, Communist, Fighter, Hayabusa, PLAAFLeo Guo

People’s Republic of China (1945-1952)
Fighter – 8+ Operated

An illustration depicting a Hayabusa in Communist service flying. (Encyclopedia of Chinese Aircraft: Volume 2)

Widely known as one of Japan’s most iconic aircraft of the Pacific War, the Nakajima Ki-43 Hayabusa’s service life was not limited to the Second World War. Shortly after the Japanese capitulation, Nationalist and Communist Chinese forces were able to capture stockpiles of firearms, tanks and planes left over by the fleeing Japanese forces. Among these were various models of the Nakajima Ki-43 Hayabusa. These were pressed into service with the Communist Chinese as an advanced combat trainer and fighter. One of the rather obscure chapters of the Hayabusa’s service life was that it was the first plane used by the Communist Chinese in aerial combat.

History

Developed in the late 1930s, the Nakajima Ki-43 Hayabusa (Type 1 Fighter) enjoyed a relatively successful service record in the Second Sino-Japanese War once introduced in 1941. The Japanese 59th and 64th Sentai (Squadrons) were the first two squadrons to receive the new Ki-43-I fighter. With barely any resistance by the Republic of China Air Force (ROCAF), the Ki-43-I helped reinforce Japanese aerial superiority over China, French Indochina, Malaya, and parts of India until the arrival of lend-lease Allied warplanes for China. Throughout the service of the Hayabusa, three major variants were issued to units: the Ki-43-I, Ki-43-II, and Ki-43-III. The Japanese also provided some of these variants to the Manchukuo Imperial Air Force in the Northeast region of China. With the end of the Second Sino-Japanese War, stockpiles of Japanese equipment was up for grabs between the Soviets, Nationalist Chinese, and the Communist Chinese. The Nationalist Chinese forces reoccupied Shanghai near the end of 1945 and captured warplanes formerly belonging to the Japanese. Among these were various models of the Hayabusa which were used to equip the 18th and 19th Squadrons of the ROCAF’s 6th Fighter Group. These Hayabusas were stationed at Shandong in preparation for the Chinese Civil War. Due to a lack of spare parts and adequate mechanics, the two squadrons were disbanded the following May.

The Communist Chinese forces were by no means idle during the immediate few postwar months. Countless guns were captured, with a considerable amount of tanks and planes as well. In October of 1945, the Communist Chinese forces captured their first five Hayabusas during the liberation of Shenyang during the Liaoshen Campaign from the Nationalists. These five captured Nationalist Hayabusas were Ki-43-II models that formerly belonged to the Japanese 4th Training Regiment. The exact model of the planes is unknown. (It is unknown if they are kō, otsu, hei, etc. variants). These five planes would be sent to the recently established Northeast Old Aviation School (东北老航校) after some refurbishing and repairs. In December of the same year, two of these planes were repaired and were planned to be ferried to the Northeast Old Aviation School. Two Japanese ferry pilots now loyal to the Communist Chinese took off from Fengjibao (奉集堡) to fly to Tonghua (通化), one of their destinations. The two Hayabusas and their pilots never made it to Tonghua however, and it is widely speculated that these Japanese pilots were unfamiliar with the geography and ended up getting lost. This is indeed a possibility but there are many other theories. It’s conceivable that the planes suffered from mechanical failure and crashed. Another possibility may be that the pilots were intercepted by ROCAF planes, but there is no proof of this.

Artwork Depicting a Ki-43 flying over Japanese trainers in the Northeast Aviation School. (Illustration by Chen Yingming / 陈应明)

The rest of the Hayabusas were eventually delivered to the Northeast Old Aviation School, where they were used as advanced trainers for fighter pilots. In April of 1948, men belonging to the Northeast Old Aviation school were able to capture an unspecified amount of Hayabusa fighters in the Chaoyang (朝阳镇) Town airport located in Jilin. This was followed by another unspecified batch of Hayabusas captured in Sunjia (孙家) Airport located near Harbin in the Heilongjiang province sometime in June of the same year. Four Hayabusas were recorded to have been repaired by the school from 1947 to 1948. Under the guidance of former Japanese and Manchukuo pilots, many of the Communist Chinese air cadets were soon able to graduate from flying in the two-seater Tachikawa Ki-55 trainer to flying solo in the Hayabusa.

In March of 1948, a number of experienced pilots and instructors were pulled from the school to form a “Combat Flying Wing” (战斗飞行大队). The 1st Squadron would use bombers and transport aircraft while 2nd Squadron would use fighters. Among these would be six Ki-43-II models. The intent of this formation was to combat Nationalist planes, but this wing never saw any combat action.

Considerations were made to use the Hayabusa in the Establishment of the People’s Republic of China parade on October 1st of 1949, but this did not happen. Despite what one may think, the Japanese planes were not withheld from the parade due to political and racial issues, but rather fear of them experiencing mechanical problems during the parade.

Communist Chinese service members standing in front of a captured Hayabusa. (*Encyclopedia of Chinese Aircraft: Volume 2*)

As such, these worn out Hayabusas were grounded. By November of 1949, there were only five examples of the Hayabusa that were still in use. These final five fighters were used by the 7th Aviation School as trainers and teaching aids. By 1952, all of the Hayabusas were finally retired from service. There are no surviving examples of the Communist Chinese Hayabusa, but there is one known photo of the Communist Hayabusa in service.

First Air-to Air Combat of the Communist Chinese Air Force

In the afternoon of October 15th 1947, four Nationalist Chinese P-51D Mustangs belonging to the Shenyang Beiling airfield took off under the leadership of Xu Jizhen (徐吉骧), the co-captain of the squadron. They were tasked with the mission of patrolling the airspace of Harbin (哈尔滨), Jiamusi (佳木斯) and the Sino-Soviet border. Upon crossing the mountains near Mishan (密山), the Mustangs squadron noticed a Tachikawa Ki-55 trainer with Communist Chinese markings belonging to the Northeast Old Aviation School preparing to land at the nearby Tangyuan (汤原) airport. This Ki-55 was piloted by Lu Liping (吕黎平) and an unnamed Japanese instructor. Xu Jizhen immediately dove for the trainer and began firing. The area immediately behind the instructor’s compartment was hit, which resulted in a fire. Watching the attack from the ground, Fang Hua (方华), a veteran Communist soldier, scrambled for a nearby parked Nakajima Ki-43-II Hayabusa and took off. Unfortunately for him, the Hayabusa was not loaded with ammunition so he was unable to engage the Mustangs. However, he was able to lead the Mustangs away from the airfield and evaded their shots until they ran out of ammo. This unfortunate skirmish was the first air-to-air combat experience the Communist Chinese had.

Debunking the Numbers Operated

According to many Western sources, the Communist Chinese Forces only operated five Hayabusas. This is however incorrect. The author believes the reason that these sources mention only five models captured was due to translation errors or simply by overlooking facts. The most likely cause of the misconception is likely due to two facts:

By the end of the Liaoshen Campaign, the Communist Chinese forces had captured five models.
By the time the PLAAF was officially established, there were five models still in service.

What these Western sources may have overlooked however, was the fact that two of the first five models captured crashed during a ferry flight in December of 1945. This leaves only three models operational.

However, a commonly overlooked fact is that the Northeast Old Aviation School was able to capture an unspecified amount of Hayabusas in the Chaoyang (朝阳镇) Town airport located in Jilin sometime in April of 1946. Another unspecified batch of Hayabusas were also captured in Sunjia (孙家) Airport located near Harbin in the Heilongjiang province in June. Due to the unspecified nature of the amount of Hayabusas captured in these two places, it only adds to the difficulty of determining how much Hayabusas were truly captured and operated. But on an inventory check done in April of 1948, a total of six Hayabusas were accounted for serving with the 2nd Squadron. According to this record, that should mean three or more Hayabusas were captured in those two airfields. That should make a total of eight or more Hayabusas when accounting for the two crashed ones. In conclusion, the author believes that a potential total of eight or more Hayabusas were captured, and operated by the Communist Chinese forces to some extent until the retirement of all models in 1952.

Gallery

Communist Chinese Ki-43-II in the colors of the Northeast Old Aviation School by Brendan Matsuyama

Sources

Gang, W., Ming, C. Y., & Wei, Z. (2012). 中国飞机全书 (Vol. 1). Beijing: 航空工业出版社., Gang, W., Ming, C. Y., & Wei, Z. (2009). 中国飞机全书 (Vol. 2). Beijing: 航空工业出版社., Allen, K. (n.d.). PEOPLE’S LIBERATION ARMY AIR FORCE ORGANIZATION., 网易军事. (2016, May 24). 老航校70周年：“鬼子飞行员”在中国当教官., Zhang, X. (2003). Red Wings over the Yalu: China, the Soviet Union, and the Air War in Korea. College Station: Texas A & M University Press., Side Profile Views by Brendan Matsuyama

North American P-51 Mustang in Communist Chinese Service

August 1, 2018Cold War, People's Republic of China, Republic of China, WW2China, Cold War, Communist, Fighter, Mustang, P-51, PLAAFLeo Guo

People’s Republic of China (1948-1953)
Fighter – 39 Operated

The North American P-51 Mustang is considered one of the world’s most iconic warplanes from the Second World War, seeing action in nearly all theaters, as well as the Korean War and many other conflicts thereafter. However, one of the lesser known stories of the Mustang is its service with the Communist Chinese forces who would go on to form the People’s Republic of China shortly after. A total of 39 Mustangs were obtained from the Chinese Nationalist forces either by capture or defection. These Mustangs were used in various roles with the Communists, and nine of them even had the honor of flying over Beijing on October 1st 1949 for a parade to commemorate the establishment of the People’s Republic of China. Although never seeing combat, the Mustangs still had served with the Communist Chinese forces as one of their most advanced fighters until the arrival of Soviet aid.

A photo displaying the rather impressive cache of captured Nationalist planes now in Communist service. In this photo, there are around nineteen P-51 Mustangs visible. (Encyclopedia of Chinese Aircraft: Volume 2）

History

The Republic of China (i.e, Chinese Nationalists under Generalissimo Chiang Kai-shek) was a notable operator of the North American P-51 Mustang during the Second Sino-Japanese War (1937-1945). Since the United States entered the Second World War, plans were made to provide the Republic of China China with modern American warplanes to replace the worn and outdated planes that the Republic of China Air Force (ROCAF) were using. The Mustangs were initially flown by pilots of the Chinese-American Composite Wing (CACW) starting from November 1944. The models they operated were P-51B and P-51C, but later in February 1945, P-51D and P-51K variants were delivered and put to use against the Japanese along with the P-51B and P-51C. At the end of the Second World War, the ROCAF received 278 Mustangs from the USAAF, most of which were P-51D and P-51K models, but also with some F-6D and F-6K photo reconnaissance models. Soon after, the uneasy relationship between the Communist Party of China under the leadership of Mao Zedong and the Nationalist government under the leadership of Jiang Jieshi (Chiang Kai-shek) disintegrated. As such, the civil war between the two parties resumed after nearly nine years of truce. This time however, the Communist forces were more prepared to fight the Nationalist forces. As time went on, the Nationalist forces began losing their hold on mainland China and were forced to retreat to Formosa (Taiwan), but not before many of their soldiers, officers and generals defected, leaving a substantial amount of equipment behind.

The People’s Liberation Army obtained their first Mustang on September 23rd 1948 when Captain Yang Peiguang (杨培光) from the Nationalist 4th Fighter Wing based in Beiping (Beijing) defected with his P-51D to the Communist forces at Siping, Jilin Province. The bulk of the Mustangs which would be captured by the Communist forces were, however, from the Liaoshen Campaign which lasted from September 12th – November 2nd, 1948. With the Communist victory at the Battle of Jinzhou on October 15th, a considerable amount of Nationalist equipment was captured; among these were thirty one Mustangs in various states of repair at the Jinzhou Airfield. Though now with thirty four Mustangs in total, the People’s Liberation Army was not able to press any into service due to many factors; the most important two being the lack of able pilots and the varying states of disrepair that the Mustangs were in.

The city of Shenyang was finally captured by the People’s Liberation Army on October 30th 1948, and on the second day of the city’s capture on October 31st, the Northeast People’s Liberation Army Aviation School sent men to secure the Shenyang Beiling airport, factories, warehouses, personnel, and various other assets formerly belonging to the Nationalists. In November, the Shenyang Beiling airport was officially established as the People’s Liberation Army Air Force Repair Factory Number 5 (中国人民解放军空军第五修理厂). With the establishment of this repair factory, the first machines to be repaired were the Mustangs. The repairs took top priority and the first Mustang was ready for service on December 30th. Since then, thirty six Mustangs were repaired within a span of eighteen to twenty months lasting until 1950.

On December 10th 1948, the People’s Liberation Army was able to capture the Nationalist-held Beiping (Beijing) Nanyuan Airport as part of the Pingjin Campaign. Three Mustangs were found in relatively good condition, and a total of 128 Packard-built V-1650 Merlin engines were captured as well. This boosted the total amount of Mustangs in the People’s Liberation Army to thirty seven, and provided plenty of replacement engines for maintenance. After this, two more Mustangs would fall in the hands of the Communist forces.

On December 29th, Lieutenant Tan Hanzhou (谭汉洲) of the Nationalist 4th Fighter Group defected with his Mustang from Qingdao to Communist held Shenyang. The last Mustang to fall into the People’s Liberation Army’s hands occured on January 14th of 1949 when Lieutenant Yan Chengyin* (阎承荫) from the Nationalist 3rd Fighter Group’s 28th Squadron defected from his home base of Nanjing to Communist held Jinan.

Lieutenant Tan Hanzhou with his Mustang shortly after his defection. (blog.163.com)

Now with thirty nine Mustangs in total, the People’s Liberation Army began to put them to use. Starting from late January 1949, a large number of Mustangs were presented to the Northeast Old Aviation School’s (东北老航校) 2nd Squadron of the 1st Air Group with the purpose of training pilots. On August 15th 1949, the People’s Liberation Army formed their first flying squadron named at the Beiping Nanyuan airfield. The squadron consisted of two Fairchild PT-19 trainers, two de Havilland Mosquito fighter-bombers and six Mustangs. Shortly after the formation on September 5th, this squadron was assigned the task of defending Beiping’s airspace from Nationalist forces. At some point before October, eleven more Mustangs were assigned to this squadron. The squadron saw no combat.

* Mr. Yan later changed his name to Yan Lei (阎磊) after his defection.

Perhaps the most notable use of the Mustangs in Communist Chinese service was on October 1st 1949. By then, the bulk of the Nationalist forces were in discord and in the process of retreating to Formosa (Taiwan). With the Communist victory inevitable, Mao Zedong proclaimed the establishment of the People’s Republic of China. A Soviet-style military parade was held in newly-renamed Beijing’s (Beiping) Tiananmen Square which included sixteen thousand and four hundred soldiers, one hundred and fifty two tanks, two hundred and twenty two cars and seventeen planes were displayed to the public. Of these seventeen planes, nine were Mustangs. The Mustangs flew in groups of threes in a V formation and led the aerial convoy. Once over Tiananmen square, these Mustangs increased their speed and flew past the square and out of sight, they made a turn and reentered Tiananmen square for the back just in time to link up with the two Fairchild PT-19A trainers flying last. Because they re-entered the square so quickly, the spectators were led to believe these were nine different Mustangs, with a total of twenty six planes appearing over Tiananmen square instead of the actual seventeen. This was mentioned in a government made propaganda newsreel. Of these nine Mustangs, at least one was a P-51K model.

After the parade, the Mustangs were once again deployed in a defensive state awaiting possible Nationalist intrusions in Beijing. By November 1949, the People’s Liberation Army Air Force was officially established and a total of twenty two airworthy Mustangs were in service, with nine more awaiting repair. This meant that thirty one Mustangs still survived, with eight written off. It is unknown what precisely happened to these Mustangs but the author speculates that they could have been cannibalized for parts, destroyed in training flights, disassembled to study the structure, or simply scrapped.

One of the only known photos of the two seat P-51D trainer. The canopy seemed to have been removed to make space. (js.voc.com.cn)

On July 26th 1950, the Beijing defense squadron was renamed the “Air Force 1st Independent Fighter Brigade” (空军独立第一歼击机大队). By then, the Soviet Union was supplying the Chinese with more modern equipment and by mid-August, the brigade’s Mustangs were replaced by Soviet Lavochkin La-9 fighters. Once replaced, all Mustangs scattered across the country were collected and given to Aviation School No.7 to train new pilots. With this, Aviation School No.7 modified thirteen Mustangs to be two-seat trainers. This was done perhaps to speed up the training process, and to prevent accidents by rookie pilots without guidance. There is currently one known photo of the two seat trainer.

By September 1953, most Mustangs were retired from training service due to cracks in the landing gear. However, eight of them remained in service with Aviation School No.7 to train Ilyushin IL-10 pilots how to taxi their planes. A few more examples were used as teaching tools to train pilots on identifying plane parts. It is unknown when precisely the Mustang was retired once and for all.

An illustration showing three P-51 Mustangs flying over Beijing on October 1st of 1949. (thepaper.cn)

Surviving PLAAF Mustangs

To this day, only two Mustangs formerly in PLAAF service survive in museums. The first one is a P-51K-10-NT “Red 3032” with the serial number 44-12458. This P-51K is on public display at the Chinese Aviation Museum (中国航空博物馆), sometimes also known as the Datangshan Aviation Museum located in Datangshan, Beijing. It remains in relatively pristine condition as it was in an indoors display and sheltered from the elements. Bomb hardpoints are visible under each of the wings which signifies that this Mustang perhaps once served as a fighter/bomber for the ROCAF.

P-51K-10-NT “Red 3032” on display. It is in rather good condition due to being stored indoors. (George Trussell)

The other surviving PLAAF Mustang is a P-51D-25-NA “Red 3” with the serial number 44-73920. This Mustang can be seen at the China People’s Revolution Military Museum (中国人民革命军事博物馆) in the Haidian District of Beijing. What is notable about this specific plane is that it was one of the nine Mustangs that flew over Beijing on October 1st of 1949 for the Founding of the People’s Republic of China parade. This Mustang was displayed outdoors exposed to nature for the majority of its life until the museum went under renovation when it was finally moved indoors. The Mustang has gone through minimal restoration, as it looks considerably cleaner than when it was displayed outdoors. This Mustang also had bomb hardpoints under its wings.

The P-51D-25-NA “Red 3” in its new indoor display after the museum renovation. It looks considerably cleaner than when it was displayed outdoors. (Wikimedia Commons)

The P-51D-25-NA “Red 3” in its old outdoors display, dust and slight rust can be seen on the machine. (Wikimedia Commons)

Variants Operated

A total of 39 North American P-51D Mustangs were operated by the Communist Chinese forces, and later the People’s Republic of China. Within these Mustangs, an unknown amount were P-51D and P-51K models.

P-51D – An unspecified amount of P-51D Mustangs of various block numbers were operated by the People’s Republic of China. A P-51D-25-NA is confirmed to have been in service as it flew over Beijing as part of the establishment of the People’s Republic of China parade and is now in the China People’s Revolution Military Museum (中国人民革命军事博物馆) in the Beijing.
P-51K – An unspecified amount of P-51K Mustangs of various block numbers were operated by the People’s Republic of China. A P-51K-10-NT is confirmed to have been in service as it is in the Chinese Aviation Museum (中国航空博物馆) in Beijing.
P-51 Trainer – A total of thirteen Mustangs were modified by Aviation School No.7 in 1951 to be two-seat trainers. The instructor sat in the rear while the student pilot was at the front. No surviving examples are preserved to this day.

Note

The author would like to extend his thanks to Mr. Hemmatyar for restoring some of the photos used in this article.

Gallery

P-51K-10-NT “Red 3032” displayed in the Chinese Aviation Museum in Datangshan, Beijing. Illustration by Brendan Matsuyama

P-51D-25-NA “Red 3” displayed in the China People’s Revolution Military Museum in the Haidian District of Beijing. Illustration by Brendan Matsuyama

A PLAAF P-51D/K with a blue rudder. The unit and serial number is unknown. Illustration by Brendan Matsuyama

A rare photograph of a mini P-51 Mustang model with PLAAF markings dated some time in the early 1950s. Two little boys accompany the cutout. This shows how impactful the Mustang was to the initial years of the People’s Republic of China. (eBay)

22 year old Lin Hu (林虎) with his P-51K before taking off to partake in the parade. (gogonews.cc)

A still frame showing three P-51 Mustangs flying over Beijing. (Establishment of the People’s Republic of China Parade)

A line of P-51 Mustangs awaiting inspection with their respective pilots standing at ease. (sohu.com)

A PLAAF Mustang taking off. Note the rocket rails. (Encyclopedia of Chinese Aircraft: Volume 2)

Mechanics and ground crew doing engine work on a Mustang. (Encyclopedia of Chinese Aircraft: Volume 2)

Four Mustangs line up on the Beijing Nanyuan Airfield awaiting to take off for the participation in the 1949 parade. Two Curtiss C-46 Commandos can also be seen in the background. (windsor8.com)

Sources

Gang, W., Ming, C. Y., & Wei, Z. (2009). 中国飞机全书 (Vol. 2). Beijing: 航空工业出版社., 八一战鹰大全（一）—— P-51“野马”战斗机. (n.d.). , Armstrong. (n.d.). 天马行空: 纪念 P-51 野马战斗机升空六十年., 肖邦振, & 李冰梅. (2010). 新中国成立前后国民党空军飞行人员驾机起义探析. 军事史资料., Allen, K. (n.d.). PEOPLE’S LIBERATION ARMY AIR FORCE ORGANIZATION., (2016, December 19).开国大典——1949国庆大阅兵, Side Profile Views by Brendan Matsuyama

Saab 21 / 21R

August 23, 2016Sweden, WW2Fighter, Flygvapnet, SaabMario H Zorro

Sweden (1945)
Fighter / Attack Plane – 298 Built

The Saab J 21 is a peculiar airplane, not only because of its advanced features. This fighter in particular is one of the only two airplanes that were initially powered with a piston-propelled engine, then later modified to incorporate a jet engine using the same airframe and implementing very few modifications. This airplane is also the product of Swedish defence concerns and resourcefulness, as Sweden wanted to keep its neutrality and territorial integrity during WWII, electing to develop a domestic fighter program as access to foreign advanced technology was restricted.

A single-seat, single-engine airplane that later became one of the first-generation jet fighters. Its design is a twin-boom tail pusher configuration. It had two longitudinal booms, attached to the main wing but extending backwards from the middle section of each wing, with the main body placed in the middle. Similar to the Lockheed P-38. This design also implements a rear mounted piston engine, otherwise known as a pusher configuration, which made engine modifications easy.

The piston-propelled version, the J 21 – had the engine, a licensed Daimler-Benz DB 605B, simply fitted at the rear of the main body, behind the cockpit and between the longitudinal booms. The jet version – J 21R – was fitted with air in-takes at both sides of the fuselage, having the engine (a De Havilland Goblin 2 and later a Swedish-licensed version, a Flygmotor RM1) located on the same area as the piston-propelled version and elongating the main body. The fuselage section harbouring the engine was also widened. Another modification was that the elevator was placed at the upper area of the double tail plane. The wing in both configurations was a low-wing, being straight until it met the longitudinal booms, changing into a slightly swept wing from the longitudinal boom to the wing tip. It also received wingtip fuel tanks.

The J 21 could develop speeds up to 645 km/h (400,78 mph), while the jet propelled version could develop speeds up to 800 km/h (497 mph), being a fast aircraft in both configurations. Its firepower (J 21) was equally powerful, as it was armed with a 20 mm cannon, either a Bofors or a Hispano-Suiza HS.404, and 2X 13,2mm Bofors machineguns at the nose, with 2X 13,2mm Bofors machineguns in the wings. The J 21R received an even much more considerable firepower, as it featured a 20mm Bofors cannon, 4X 13.2mm M/39A heavy machine guns, a centreline pod with 8X 13.2mm M/39 machineguns, and wing racks for 10X 100mm, 5X 180mm, or 10X 80mm anti-armour rockets.

Saab J 21 Prototype — Prototype in Service

The J 21 was initially developed with the aim of providing Sweden with good air assets to defend its air space and neutrality, and also with the aim of replacing many of the existing airplanes development. The development began in 1939, under the lead of Frid Wänström, having as basis a Bristol Taurus as an engine, yet it fell into a momentary freeze until 1941, when it was resumed. This freeze was due to Saab’s concentration in the Saab B 17 and B 18 bombers. As the configuration resulted problematic for the pilot’s safety when bailing out, many proposed solutions came, such as blowing the propeller, blowing the entire engine or using a “bomb crutch” to throw the pilot away from the airframe. The solution came with the development and implementation of a Bofors ejection seat, which was tested first on ground and in-flight on a SAAB B 17. The nose landing gear wheel was tested on a steel platform attaching the three undercarriage components, with the structure being towed by a truck during the test programme. In 1943 the first flight of the prototype took place, with units entering in service with the Flygvapnet in 1945. Three prototypes were built during the development process. In 1947 the J 21 evolved into de J 21R when it received the De Havilland Goblin jet engine, but as the J 29 Tunnan was introduced, it replaced the J 21 as the main fighter, performing the J 21 instead ground attack missions, thus designated A 21R.

The J 21 was in service with the Flygvapnet from 1945 until 1954, with 298 fighters built from 1945 to 1949. The J 21R was in service with the Flygvapnet from 1950 until 1956, with 60 units built from 1950 to 1952. Three J 21 are preserved as static displays in museums.

Design

The basic design of the J 21/J 21R was a twin-boom tail pusher propeller, making it one of the most radical operational designs of those times. This scheme proved to be beneficial for two important aspects. First, it benefited both pilot view forward and allowed the armament to be concentrated on the nose, meaning that such combination provided a good firing scope and sight, let alone a good firepower and making maintenance services rather easy. Second, it made possible for the aircraft to be updated thus being able to install a jet engine using the same airframe of the piston-propeller engine version, which was basically the basic airframe.

The only drawback of this layout – mainly with the J 21 piston-propelled engine version – was the risk for the pilot to hit the blades when bailing out, as the engine was placed right behind the cockpit. The solution came with one of the first ejection seats in the world, developed by Saab in 1943, being tested on the ground and on-flight and being a SAAB B 17 the testing platform. Another drawback was that, similar as the earlier versions of the Mustang P 51, the rearward view was rather poor, which could be problematic in a dog-fight. The J 21 featured a characteristic wing, as it was roughly strait from the main fuselage to the tail twin-booms, then being slightly swept back from the tail booms to the wingtips.

The wing was purposed with acquiring laminar flow as far as possible. In regards to the aerodynamics, it was required the airframe to reduce minimum drag and engine cooling drag, so the oil and liquid coolers, along with the duct system for the engine, inside the airfoil contour between the fuselage and the tail booms. Considering the tail boom design, the horizontal elevator was placed between the tail sections, connecting them. The landing gear, meanwhile, was of tricycle configuration and long, which made the J 21 to be a tall aircraft so to keep the propeller away from the ground. The rear gear retracted into the tail booms behind the rear wing spar, but this forced the fuel tank to be placed in the wing centre section. The frontal wheel was located at the nose.

The engine was a Daimler-Benz DB 605B inverted V12 of 1475 hp, which gave the airplane speeds of maximum 645 km/h (400,78 mph), but as the engines were received in poor conditions, improvements and overhauling were required. As a result of the power provided by this engine and the aerodynamic characteristics, the J 21 was deemed good, as it had excellent handling, benign stall characteristics and tight turning circle. The armament also gave this fighter good firing power, with the Swedish pilots being able to compare it with the Mustang P 51D (Sweden received a good number of them) and considering they were a good match for it. But the main drawbacks were that at medium and high altitudes performance tended to decrease, the rearward view was poor, and the controls were heavy to operate, increasing tiring during combat.

The armament of the J 21 consisted of a 20 mm cannon, either a Bofors or a Hispano-Suiza HS.404, and 2X 13,2mm Bofors machineguns at the nose, with 2X 13,2mm Bofors machineguns in the wings. The J 21A-3 was able of carrying unguided rockets (2X 180mm or 8X 80/145mm) and bombs (600kg, 500kg, 250kg or 4X 50Kg).

After World War II, the jet engine technology was becoming the mainstream propulsion system, and the Flygvapnet wanted to catch up and incorporate such technology into its assets. As the development of a new jet propelled fighter would take some time, the J 21 was chosen to be the platform for using an airframe in use with the new technologies back then. As a result, the J 21R was developed and introduced, with the first prototype taking flight in 1947 and then entering service in 1950. This ‘new’ fighter required some structural changes so to cope with the new power plant, like up to 50% of its airframe. First, the main body was slightly prolonged ant widened, so to allow the De Havilland Goblin 2/Flygmotor RM1 engine (that allowed speeds of 800 km/h) and the air intakes, located at each side of the fuselage. In addition, the stabilizer was moved upwards top to the fin, so to allow the engine flow, requiring the tails to be redesigned. The wing leading edge was mover forward and made sharper. Airbrakes were introduced, one upward and other downward flaps placed on the outer wing’s trailing edge. Given the increased speed, the ejection seats were properly modified so to enable ejections at subsonic speeds. And as the propeller was removed, the landing gear was shortened in turn, reducing the height of the airplane. Fuel tanks were fitted in the middle wing and the wingtips, which increased the fuel volume.

The J 21R received an enhanced firing power, as the standard 20mm cannon/4X 13,2mm M/39A heavy machineguns set was added with a centreline external pod carrying 8 additional 13,2mm M/39 heavy machineguns. In addition, the J 21R was fitted with wing racks allowing the airplane to carry 10X 100mm or 5X 180 Bofors rockets, or 10X 80mm anti-armour rockets.

Materializing ‘Armed Neutrality’

The J 21 is, like the J 29 Tunnan, the product of Sweden’s concerns about its own security during WWII, especially in the light of Germany’s invasions of Norway and Denmark in 1940, which were neutral nations by the time. As Sweden considered that its existing air assets wouldn’t be able to successfully contribute to the defence, given their obsolete condition, it considered that new aircraft were necessary. As with the J 29, Sweden faced some problems when trying to acquire some technology due to the restrictions imposed by the conflict, although by sheer luck it was able to receive the Daimler-Benz DB 605B engine, as Germany was trying to hamper the delivery. These circumstances decided the Swedish government to undertake a local rearmament programme and implement a policy of ‘armed neutrality’ to secure the nation’s neutrality. The focus was placed on the development and fabrication of advanced aircraft. As the same concerns prevailed after World War II and into the very earlier days of the Cold War, it was deemed that the resulting technologies from the War needed to be exploited and incorporated, having in mind Sweden to catch up with the newly developed technologies, especially in regards of propulsion. The Saab J 21 became the platform for the Flygvapnet to make the transition from piston-propeller engine to jet engine, while at the same time providing the country with a locally built jet engine fighter, while newer and more advanced aircraft were put into service.

A feat of Swedish Nytänkande

The fact that the J 21 was used as a basis for an almost new jet powered engine fighter is a product of Sweden’s innovative thinking and also of its capacities – out of need, in part – of working with existing resources at the point of maximizing them. While the J 29 Tunnan has the honour of being the first jet fighter exclusively built for that purpose, it is the J 21 the very first jet engine fighter the Flygvapnet operated with, being amongst the very few designs, if not the only one, in being successfully modified as it received two different types of power plants. And while the J 29 Tunnan displaced the J 21 as a fighter, it was able to operate as a good ground attack aircraft until 1956, making this airplane born in the World War II, an early Cold Warrior and the basis for Sweden’s jet fighter industry and operationalization. It simply meant a huge step for the Swedish Air Industry, let alone its Air Force.

Variants of the J 21

J 21A-1 – Fighter version and the very first production series of the J 21. It featured the armament configuration of the 20mm Hispano-Suiza HS.404 cannon and the 13,2mm Bofors/Colt heavy machine guns. In service until 1949. 54 delivered.
J 21A-2 – Fighter version and the second and third production series, featuring enhanced avionics and incorporating a Bofors 20mm gun, with the other armament being the same. It was also equipped with further direction horizon instruments. In service until 1953-1954. 124 delivered.
J/A 21A-3 – Fighter/fighter-bomber version based from modified J 21A-2 airframes. It was equipped with a SAAB BT9 bomb aiming sight and two RATO (Rocket-Assisted Take-off) devices, armed with unguided rockets (2X 180mm or 8X 80/145mm) and bombs (600kg, 500kg, 250kg or 4X 50Kg). 119 delivered.
J 21B – A planned version to be armed with 3X 20mm guns at the nose, a radar in the starboard room, improved aerodynamics and better engines (A Daimler-Benz DB 605E/Rolls-Royce Griffon). It was also intended to feature a pressurized cockpit and a bubble canopy. Cancelled

Variants of the J 21R

J 21RA / A 21RA – First production series powered by a De Havilland Goblin engine. Later reconfigured into ground attack airplanes (A 21RA). Fitted with wingtip fuel tanks to increase the operational range and endurance. Operated until 1953. 30 delivered.
J 21RB / A 21RB – Second production series powered by a Swedish-license made De Havilland Goblin (RM1). It was also reconfigured later into a ground attack airplane (A 21RB), with the nose heavy machineguns changed to a 12.7mm caliber. Fitted with wingtip fuel tanks to increase the operational range and endurance. Operated until 1956. 30 delivered.

Operators

Sweden -The Flygvapnet operated the J21 a time roughly after the end of World War II. It operated with 54 fighters of the J 21A-1 version, 124 The J 21 fighters of the J 21A-2 version, and 119 fighter/bombers of the J 21A-3 version. The J 21 was in service between 1945 and 1954, with X units: F9 Goteborg, F15 Soderhamn, F12 Kalmar, F6 Karlsborg and F7 Såtenäs. In addition, the Flygvapnet operated with 30 fighters of the J 21RA version, and 30 fighters of the J 21RB version. Both were later on modified into ground attack airplanes, being denominated as a result A 21RA and A 21RB. The J 21R was in service from 1950 to 1956, with three units: The F10 Ängelholm, the F7 Såtenäs, and the F17 Kallinge. Three J 21 remain today as museum exhibitions in Sweden.

21 Specifications
Wingspan	11,6 m / 38 ft 0 in
Length	10,44 m / 34 ft 3,02 in
Height	3,97 m / 13 ft 0 in
Wing Area	22.2 m² / 238,87 ft²
Engine	1 Daimler-Benz (SFA) DB 605B inverted V12 of 1475 hp
Maximum Take-Off Weight	4431 Kg / 9,768.6 lb
Empty Weight	3250 kg / 7,165 lb
Loaded Weight	4150 kg / 9,149 lb
Maximum Speed	645 km/h / 400,78 mph
Range	750 Km / 466 miles
Maximum Service Ceiling	11000 m /36,090 ft
Climb Rate	15 m/s (2,950 ft/min)
Crew	1 (pilot)
Armament	1 X 20 mm Hispano-Suiza HS.404 or a Bofors cannon located at the nose. 2 X 13,2 mm Bofors (Colt) heavy machine guns located at the nose. 2 X 13,2 mm Bofors (Colt) heavy machine guns located at the wings. The J 21A-3 fighter/bomber version could carry also 2 X 180mm, or 8X 80/145mm rockets; and 600kg, 500kg, 250kg or 4X 50Kg bombs

21R Specifications
Wingspan	11,37 m / 37 ft 4 in
Length	10,45 m / 34 ft 3 in
Height	2,90 m / 9 ft 8 in
Wing Area	22.3 m² / 260,0 ft²
Engine	1 De Havilland Goblin 2 Turbojet (Svenska Flygmotor RM2B Turbojet)
Maximum Take-Off Weight	5000 Kg / 1,0230 lb
Empty Weight	3200 kg / 7,055 lb
Loaded Weight	N/A
Maximum Speed	800 km/h / 497 mph
Range	720 Km / 450 miles
Maximum Service Ceiling	12000 m /39,400 ft
Climb Rate	17.1 m/s (3,366.1 ft/min)
Crew	1 (pilot)
Armament	1 X 20 mm Bofors cannon located at the nose. 4 X 13,2 mm M/39 heavy machine guns located at the nose, later changed to 12.7mm caliber. 8 X 13,2 mm M/39 heavy machine guns on a centreline pod. Wing racks allowing 10X 100mm, 5X 180mm, or 10X 80mm anti-armour rockets.