While they had been manufacturing Western designs under
license in the 1920s, Japanese aircraft builders had been catching up on the
fine points of aeronautical design. In the early 1930s, they were ready to
proceed with designs of their own.
In February 1934, Imperial Navy air headquarters issued a
9-shi specification calling for a new single-seat fighter. Although
carrier-based capability was virtually implicit in a navy requirement, one of
its chief architects, Lt. Cmdr. Hideo Sawai, had deliberately avoided specific
reference to such characteristics, concerned that it would inhibit the
designers. In contrast to British and American naval aviation planners, Sawai
wanted the manufacturers to produce a high-performance fighter that would bring
Japan up to world standard—the matter of adapting and equipping it for
operations from carrier decks would be dealt with afterward. The specification
called for a maximum speed of 350 kilometers per hour (217 miles per hour) at
3,000 meters (9,840 feet) and the ability to climb to 5,000 meters (16,405
feet) within 6.5 minutes. Armament was to consist of two 7.7mm machine guns,
wingspan would not exceed 11 meters (36 feet), and length no more than 8 meters
(26 1/2 feet).
Among those who sought to meet the requirement was
Mitsubishi’s chief designer, Jiro Horikoshi. After giving cursory consideration
to other configurations, Horikoshi determined that the fighter must be a
low-wing monoplane, with attention paid to the cleanest possible aerodynamics
and to the minimum possible weight. The airframe he designed used stressed-skin
aluminum over a two-spar box-type wing structure of inverted gull form, which
was later altered into a flat center section with dihedral for the outer wing
panels. After considering the possibility of incorporating retractable landing
gear into his design, Horikoshi rejected it on the grounds that the 10 percent
decrease in drag would result in only a 3 percent increase in speed, not enough
to justify the system’s greater weight and complexity. Instead, his monoplane
would have fixed undercarriage, with streamlined fairings over the wheels.
The first Ka-14 prototype, powered by a 550-horsepower
Nakajima Kotobuki 5 nine-cylinder radial engine, was completed in January 1935,
just eleven months after Mitsubishi received the 9-shi specification. During
its first flight tests in February, it reached a speed of 444 kilometers per
hour (276 miles per hour) at 10,500 feet, exceeding both the navy’s requirement
and Horikoshi’s own expectations. Nevertheless, the Ka-14 had a great obstacle
to overcome when it competed with the Nakajima A4N1 biplane in the autumn of
1935, because of the almost insurmountable prejudice in favor of dogfighting
capabilities over all others among senior JNAF officers. The Ka-14’s low wing
loading made it extremely maneuverable for a monoplane, but it still could not
match the maneuverability of the A4N1—until the rules of mock combat were
altered to include climb and dive tactics. That change gave the Ka-14 such an
overall edge that even Minoru Genda, one of the most ardent biplane partisans,
was won over to the new type.
After further development—and an unsuccessful attempt to
interest the army in the design—Mitsubishi was able to put its monoplane into
production as the A5M1 Model 96 carrier fighter in the autumn of 1936. An
improved version with a 610-horsepower Kotobuki 2 KAI 3ko engine, a longer
chord cowling, and a three-blade propeller in place of the two-blade airscrew
entered production in the late spring of 1937 as the A5M2-ko. The outbreak of
war with China on July 7, 1937, lent urgency to the JNAF’s efforts to hasten
the A5M to operational units, and the newly formed 13th Kokutai (Air Group) got
its first monoplanes just four days later.
“Battle of Shanghai”
Initially, the Japanese army advanced quickly, taking Beijing
and Tientsin; but resistance stiffened as it approached Shanghai, and at the
same time Japan’s regular arsenal of biplanes was proving unable to achieve a
decisive degree of air superiority over the mixed bag of Chinese aircraft that
opposed them. The need for such an edge became critical on August 14, when nine
Mitsubishi G3M2s of the Kanoya Kokutai, led by Lt. Cmdr. Shinichi Nitta, left
Matsuyama (Sung Shan) air base near Taipei, Taiwan, crossed the Formosa Strait
and tried to bomb Jienqiao training field near Hangzhou, while another nine
G3Ms led by Lt. Cmdr. Nantaro Asano attacked Guangde airfield. Chinese
intelligence had learned of the coming mission and Colonel Kao Zihang,
commander of the 4th Pursuit Group at Zhoujiakao, had ordered his 21st, 22nd,
and 23rd Squadrons to Jienqiao, where their Curtiss Hawks would refuel and take
off to intercept the raiders.
Kao’s fighters were the last of a long line of classic
biplanes that had begun in 1925 with the P-1 Hawk (the first Curtiss to bear
the name), and which culminated in the F11C-2 Goshawk. Final refinements in the
Goshawk were metal wings and hand-cranked retractable landing gear on the
XF11C-3, inspired by that of the Grumman XFF-1 two-seat fighter. Entering US
Navy service in May 1933, the F11C-3—later redesignated as the BF2C-1
fighter-bomber—joined the Grumman F3F and Polikarpov I-153 as the only
single-seat biplane fighters with retractable undercarriage to achieve quantity
production.
Export versions of both Goshawk variants reverted to wooden
wing structures, the fixed-gear plane being called the Hawk II and the
retractable model the Hawk III. Powered by a 740-horsepower Wright R-1820-F53
radial engine, the Hawk III had a top speed of 240 miles per hour, mounted two
.30-caliber Browning machine guns, and served in the air arms of Thailand and
Argentina as well as China, which imported its first twelve in March 1936.
Another ninety arrived in crates and were assembled at the Central Manufacturing
Company at Hangzhou. The Chinese had seventy-two operational when the Japanese
invaded, as well as fifty Hawk IIs.
August 14 began with Chinese air attacks against the
Japanese army in Shanghai and against supporting naval units offshore, including
Hawks of the 5th Pursuit Group carrying one 250-kilogram bomb each. Lieutenant
Liang Hongwen in plane No. 2401 of the 24th Pursuit Squadron was credited with
hitting the stern of the Japanese light cruiser Idzumo off Nantong, but it
turned out to be a near miss—which was fortunate, since his target was in fact
the British heavy cruiser Cumberland. Two other Chinese bombs fell near the
American heavy cruiser Augusta. Another “international incident” occurred that
afternoon when three Hawks from the 24th attacked the Japanese-occupied Kungda
Textile Factory, but one of their bombs fell on the Nanking Road in the
International Settlement. Meanwhile, Liang came under attack by an aggressively
flown Nakajima E8N1 floatplane from the light cruiser Sendai, and was so badly
shot about that he had to force land and died of his injuries soon after. Next,
five Hawk IIs and nine Hawk IIIs made another attempt to bomb the Kungda
factory, and some also attacked the floatplane, scoring fifteen hits before it
lost them in a cloud.
Poor though the Chinese bombing performance was, it spurred
Vice Adm. Kiyoshi Hasegawa, commander of the Japanese Third Fleet, to order
attacks against their airfields. Due to typhoon weather conditions, however,
the only unit game to defy them was the Kanoya Kokutai with its modern
G3Ms—all-metal twin-engine monoplanes capable of 232 miles per hour and of
mounting three 7.7mm machine guns. They took off at 1305 hours Formosa time,
but storm clouds and poor visibility limited their altitude to 1,641 feet. They
would also have to carry out their mission without fighter escort, but the
Japanese were not overly concerned, arrogantly assuming that they would not
need it against the inept Chinese.
The 4th Group’s Hawk IIIs were still in the process of refueling
at Jienqiao when Nitto’s bombers arrived, strung out due to the weather, which
made it hazardous to fly in formation. Kao, boarding his personal Hawk III
marked IV-I, ordered all fighters to scramble up, ready or not. This had grave
consequences for two of them—Hawk III 2105 of the 21st Pursuit Squadron ran out
of fuel and crashed, mortally injuring Lt. Liu Shufan, and 2106 force landed,
injuring Lt. Chin Anyi. The rest laid into the Japanese, and Colonel Kao, after
silencing two gunners, closed to twenty meters to shoot a G3M, piloted by Petty
Officer 3rd Class Iyoshio Momosaki, down in flames over Banshan. He then
attacked Warrant Officer Fujio Yamashita’s bomber, crippling its left engine
with fourteen hits, along with twenty-one in its right wing, and thirty-eight
to the fuselage before his fuel gave out, compelling him to disengage and force
land at Jienqiao. A third G3M, piloted by Petty Officer 1st Class Yanase
Mitsui, and which was swarmed by 21st Squadron Hawk IIIs flown by Capt. Lee
Guitan, Lt. Wang Wenhua, and Liu Chisheng, went down near Chiaosi.
At 1800 hours Asano’s nine G3Ms arrived over Guangde in V
formation but only scored one bomb hit. As they made for home, they encountered
Capt. Chow Tingfong, commander of the 34th Provisional Pursuit Squadron, who
had been test-flying a Hawk III. Although he had no ammunition, Chow attacked
and managed to break up the formation. As the Japanese flew on, they ran into
the 22nd Pursuit Squadron, and one of its pilots, Lt. Cheng Hsiaoyu, hit the
right engine and wing tank of Warrant Officer Hitoshi Ogawa’s G3M. Ogawa
pressed on for Taiwan but ran out of fuel short of his goal and ditched near
the Keelung harbor lighthouse, where he and his crew were rescued. Yamashita
managed to get his riddled bomber back to Matsuyama on one engine, but its
landing gear collapsed on landing, and it was written off.
Though overlooked in the West, the “Battle of Shanghai” had
multiple significances in aviation annals. In 1940 the Republic of China
pronounced August 14 as “Air Force Day.” Indeed, Colonel Kao had scored his air
arm’s first aerial victories. To his shared kill that day, Liu Chisheng would
add ten more flying Hawks, I-16s, and I-152s, to become China’s ace of aces and
a major general in the Republic of China Air Force. In terms of air strategy,
the Chinese fighters’ success struck a serious blow to Italian general Giulio
Douhet’s widely accepted theory that bombers alone could win wars. Conversely,
the Japanese were rudely awakened to the folly of sending their bombers in
unescorted, and to the critical need for a fighter capable of seizing control
of the sky.
Land-based Japanese navy units, augmented by the air groups
of the light carrier Hosho off Shanghai, were joined on August 15 by the large
carrier Kaga, and both vessels achieved a marginal degree of local air
superiority with their aging Nakajima A2N1 fighters.