Debut in the Chinese Sky, Fighter “Kawasaki” Ki-10
by Vyacheslav Kondrat’ev
translated by George M. Mellinger, Twin Cities Aero Historians

(This article by the estimable Mr. Kondrat’ev, one of Russia’s finest aviation historians, appears to have been published originally in an undetermined Russian magazine, and later scanned and posted to the above website. Our thanks to Ken Glass for calling this article to my attention. I express reservations about some of my translation; my understanding of the Russian engineering vocabulary being absolutely minimal, and of the English equivalents only slightly better. But this should effect only the last part of the article.)

At the beginning of September 1939 the culmination of the battle at the Khalkin-Gol River was already past. The Soviet forces having surrounded and destroyed a portion of the Japanese group which had invaded Mongolian territory forced the enemy to withdraw to the line of the border. But if the Japanese army had suffered heavy losses and was not yet thinking of revenge, the Imperial aviation though it had also suffered heavily in the air battles , was not ready re accept its defeat. And almost daily in the sky above the arena of recent battles littered with burnt-out tanks, there raged sharp air battles.

On one of the first days of fall Senior Lieutenant Fyodor Cheremukhin, a deputy squadron commander of the 22 IAP, took off for a combat patrol. Soon he noticed a group of Japanese aircraft that had appeared from across the river. Giving the sign to his wingmen, Cheremukhin turned his I-16 toward the foe. For him it was far from the first battle and he knew well the outline of the main Japanese fighter the Ki-27 - a cantilevered monoplane with a closed cabin, and a large air-cooled motor. But this time the Soviet pilots met an entirely different machine..An elegant, sharp-nosed biplane, keenly reminding the deputy squadron commander of the old Polikarpov I-3, on which he had some time ago begun his career as a military pilot.

Getting tied up in an aerial carousel quickly showed that the Japanese fighter excelled the Ishak (the I-16) in turning, and was notably inferior to it in speed and climb. our pilots quickly understood that they could better beat them from a distance, and not joining in a close battle, exited to repeat their attack from the vertical.

Soon Cheremukhin managed to get on the tail of one of the Japanese and gave him an aimed burst. From the biplane there issued a plume of white steam.”Damaged the radiator”, the Senior Lieutenant noted to himself, and quickly cut back the throttle so as not to overshoot the opponent. Perhaps the Japanese pilot lost his head or was wounded, but he did not even try to maneuver to escape from the fire, but continued to fly straight ahead, losing altitude and trailing a long trail of steam.

Again aiming carefully, he put a long burst of fie into the motor of the damaged machine. Instead of steam from the Japanese, there was a thick puff of black smoke, went into a steep dive and exploded on the ground.

This, according to F. N. Cheremukhin’s recollection, was the first Soviet meeting with the already outdated Japanese fighter, the Kawasaki Ki-10.

We could begin the history of the design of this aircraft in the mid-1920s, when Japan, like a number of other countries, lagged in the development of aircraft and not having their own schools of aircraft design decided to resort to the help of foreign specialists. Germany provided the greatest possibilities in this regard, having been deprived by the Versailles Treaty of the right to construct military aircraft, but having a great quantity of highly qualified aeronautical engineers. The firm Kawasaki (the full name Kawasaki Kokuki Kogio Kabushiki Kaisha) offered the position of chief designer to the German engineer Richard Vogt.. His touchstone in Japan was the design of the KDA-5 multi-purpose military biplane, adopted for service in 1930 in one- and two-place variants.

At the beginning of 1934 Vogt entered the Imperial Army fighter competition, his new design, an all-metal cantilevered monoplane, the Ki-5. In its aerodynamic qualities this aircraft reached the highest levels in the world. However, the military command judged the machine too revolutionary and on the pretext of a high landing speed declined to acquire it. Vogt, taking offense, soon left Japan and returned to the Fatherland, which following the rise to power of the Nazis began the development of a gigantic aviation program. Joining the firm of Blohm und Voss, he eventually achieved fame for the creation of heavy multi-engine flying boats.

But we return to Kawasaki. During his years of working at this enterprise, the German engineer managed to prepare a group of capable designers, among them his assistant Takeo Doi. He became chief of the construction bureau after the departure of Vogt. From his unfortunate experience with the Ki-5 project Doi drew an important conclusion, it is not necessary to try to run ahead of a locomotive. Therefore, his first creation, in conjunction with designer Isamu Imachi, the Type 95 Fighter, was a conventionally braced biplane of mixed surface construction. However in its interior construction the machine showed an obvious aerodynamic debt to Vogt’s Ki-5.
As a result, Takeo Doi managed to create a completely successful aircraft enjoying good flying characteristics. First taking to the air in February 1935, the Type 95 boasted in testing a maximum speed of 400 kmph, perhaps at that time the best speed for aircraft of biplane construction. All the other flight performance figures were considered satisfactory and the Type 95 emerged victorious from the series of competitions to “fill the vacant office” of army aviation fighter. (the air force did not exist as a separate branch of service in Japan at that time.) The firm received a contract for construction of 320 examples of the aircraft.

In the army the airplane received the designation Ki-10-I (first modification).. The first series Ki-10s began to enter service in December 1935. Military pilots highly valued the speed and climb of the new fighter. However, soon the firm began to receive persistent requests to improve the horizontal maneuverability of the machine. In Japanese aviation the point of view still predominated that a fighter most of all should meet the requirement of high maneuverability for close-in turning battles in the hand-to-hand style of the first world war. Also noted was inadequate stability (yawing), making accurate aiming of fire difficult.

In response to these claims Takeo Doi in fulfillment of the contract, in October 1937 offered a new modification, designated Ki-10-II. to increase maneuverability the span of the upper wing was increased by 51 cm. As a result there was an almost 15% decrease in wingloading. Also to adjust the center of balance, the tail section of the aircraft was lengthened by 35 cm, which rendered the machine more stable.

It is interesting that on account of the increased efficiency of industry, the more surface finish was able to compensate completely for the increased drag. Thanks to this, even with the same motor, maneuverability and take-off and landing performance notably improved, and basic performance figures remained without change. By the end of December 1938, when production of the machine ceased, 290 examples of the Ki-10-II wee produced by the Kawasaki factory in the city of Gifu.

By this time Takeo Doi had already completed design of the fighter monoplane Ki-28 and his former partner Isamu Imachi continued to ‘polish” the construction of the Ki-10. In 1938 he “handed down from the mountain” a total of four modifications distinguishing the form and profile of the wings, unstrutted landing gear, and finally an enclosed cockpit. With the help of these aerodynamic contrivances and addition of a more powerful motor the maximum speed of the machine was able to reach 445 knph. But all this work was in vain. the military command fundamentally changed their view of the tactics of air combat, and did not want even to consider projects for biplane fighters.

By January1937 the Ki-10 had become the main fighter of the Japanese army. Regiments and separate squadrons (In Japanese terms Sentai and Chutai) equipped with these aircraft were based in the home islands, Korea, Taiwan, and the recently occupied Manchuria. In June 1937, the Japanese, intending to seize a portion of Chinese territory on Manchuria’s border staged an incident in China, which unexpectedly for them developed into a bloody eight-year war. At that moment there were more than 200 aircraft concentrated on Manchurian aerodromes, of which 78 were Ki-10s.

Opposing the flying samurai in the region were an approximately equal number of Chinese Curtiss Hawk II fighters of American production. Despite the bravery of the Chinese pilots, the superior training and much more modern equipment quickly led to Japanese domination of the air. In October Soviet fighters began to appear in China and the first groups of volunteers arrived. But by this time the main focus of battle had shifted to the southeast and the region around Shanghai where the Japanese landed a large expeditionary force and began to push deep into the interior of the country. There only naval aviation operated, equipped with the carrier fighter Mitsubishi A5M2. It was mainly against this type that our pilots in China fought their battles.

In January 1938 the Japanese army prepared an offensive in the Xuzhou region. Redeployed there from Manchuria was the 2 Fighter Hiko Daitai (a provisional unit formed conducting for independent operations and generally consisting of two-three squadrons) under the command of Captain Tateo Kato. In their first battle, by their count, the Japanese shot down 12 Chinese aircraft of the loss of only one of heir own. If we believe Japanese accounts, such results continued. Thus on March 8 nine Ki-10s escorting bombers shot down three Chinese Gloster Gladiators without loss. And Lieutenant Kawahara alone shot down four I-15 bis.

On March 25 his success was repeated by Tateo Kato himself. On this day his Daitai again claimed twelve victories. Their own losses: one pilot wounded and two fighters force-landed. A much larger air battle occurred on April 10 over Heifeng. In Japan this battle is considered the greatest success of army aviation during the entire Chinese campaign. Twelve Ki-10s and three very new Ki-27 fighters, which had only just arrived at the front attacked 30 Chinese I-15bis. In spite of the two-fold numeric superiority of the enemy, the Japanese claimed complete victory. The official Japanese history asserts that in this battle 24 Chinese aircraft were destroyed! The Chinese were able to damage the aircraft of Lieutenant Shimokata, who had to make a forced landing deep in the enemy rear. Senior Lieutenant Tanaka landed near by to rescue him. Lieutenant Fukuyama was the only Japanese pilot killed in this battle. Wounded in the chest, he returned to his aerodrome, touched down on the landing strip and died from loss of blood.

During three months of active combat the squadrons fighting in the Ki-10 recorded their score as 86 air victories for a loss of only six pilots. However, these figures call for considerable doubt, as it is known that the Japanese pilots (in truth not only the Japanese) often exaggerated their results by several times. The previously mentioned Captain Tateo Kato was recognized as best Japanese army pilot, having shot down nine Chinese aircraft. None the less, in spite of the victory counts, the battles over Heifeng and Xuzhou marked the beginning of the end of the career of the Ki-10. From May 1938 the next generation Ki-27 monoplane fighter began to replace it.
In May 1939 at the beginning of the Nomonhan Incident, as the Japanese call he battle at the Khalkin-Gol river, there remained in Manchuria a single regiment (33 Sentai) armed with the Ki-10. Initially the high command did not plan to use against the Soviet VVS these clearly already antiquated machines. But by the end of August the first line regiments equipped with the Ki-27 had suffered such losses that they had to throw into the meatgrinder any reserves. On August 26 the 33 Sentai arrived at the front and by the beginning of September their pilots had completed several combat missions. About this, the usually boastful Japanese propaganda did not mention even the slightest successes. Our pilots reported the destruction of no fewer than three biplane fighters. (The Japanese had no other two-winged fighter except the Ki-10 at Khalkin-Gol). The Japanese admitted the loss of one and battle damage to a further four machines of this type.

Eventually the Ki-10 was transferred from the first line units to the deep rear, where they served until the spring of 1942 as local air defense interceptors, and until 1944 in the flying schools. In 1942 the Americans, knowing of the existence of an enemy biplane fighter assigned it the code name “Perry”. But they never met it in the air.

In 1939 an almost undamaged Ki-10-II was captured by the Chinese. Under still unclear circumstances this aircraft ended up in the USSR. here the aircraft was examined from every side and even went to the NII VVS for flight testing. On the base of this work was prepared “Technical description of the aircraft I-95” (At that time in Soviet documentation, all Japanese fighters were designated by the letter I and the factory index number.. The number “95” signified the 95th year of the Meiji era according to the traditional Japanese calendar.)

From the description it was noted that the I-95 is an all-metal biplane with non-retractable landing gear and an open cabin. The powerplant is a German licenced BMW 9 (Japanese name Kawasaki Ha.9-II-Ko) - twelve cylinder, two-row, water cooled, with a centrifugally driven supercharger. Power, produced in NII VVS tests was 800 hp (860 hp according to Japanese sources).The propeller was metal, three-bladed with a pitch adjustable on the ground. The water cooled radiator, with air flow regulating lattice blinds at the front, was located underneath the motor in an enclosed tunnel arrangement. Between the propeller spinner and the motor was located an annular-shaped combined oil reservoir and cooler, of a ribbed appearance.

The fuselage was semimonocoque of overlapping machined Duralumin. Similar technology simplified assembly, but for the lowering of resistance due to friction, joints were puttied and covered with a thick layer of paint and lacquer. As a result, the outer finish was so careful that (Attention modelists - cut the “carving”) that even up close it was impossible to discern the joints between the Duralumin panels. Excluding, of course, the various hatches, and inspection panels and cowling.

The biplane wing structure consisted of the upper, wing, “load-bearing ailerons” (internally balanced?), and the lower, structurally divided into the center and outer sections. The wings were joined by “N” shaped struts of tear-drop shaped cross-section and wire braces. Two Duralumin, flush-riveted longerons served as the main lift elements of both wings. The surfaces were fabric covered, except for the Duralumin leading edges (In the first modification of the Ki-10-I, the wing leading edges were covered with plywood.)
The cantilever tail was of all metal construction. The fin was fully engaged with the fuselage. The surfaces of the fin and stabilizers were Duralumin sheet while the rudder and elevators were fabric covered. There were trim tabs on the elevators. Controls of the elevators and ailerons were rigid rods, and the rudder was controlled by cable.

The undercarriage was of the standard type, split, with oil-spring shock absorbers and mechanically actuated wheel brakes.. The tail strut was self-orienting. All machines were produced with faired wheel spats, but they were usually removed at field aerodromes.
Armament consisted of two 7.7mm caliber, synchronized, “Vickers-Arisaka type 89” machine guns with 450 rounds per gun. The machine guns were located above the motor, and the firing button, very originally, was located not on the control stick but on the throttle lever. The tube of the optical sight (in the technological description designated as OP1) extended through the windscreen.

Flight navigation equipment and air navigation lights made night flight possible. The fighter was provided with an apparatus for oxygen, and commanders’ machines had radio equipment.

During the years 1935-1939 all Ki-10s were finished according to the standards of Japanese army aviation in a very light greenish-gray color. At a distance the color appeared almost white. National markings, a bright red circle - the Hinomaru, were marked only on the wings at that period. On the fuselage and tail surfaces usually were present transverse (rarely - diagonal) bands in white, red, or yellow color in various combinations, signifying membership in this or that unit. Sometimes on the tail a hieroglyph was marked, noting the name of the pilot. In 1939 some aircraft based in Manchuria were finished in a dark camouflage green.

Technical Flight Characteristics
(data in brackets from NII VVS testing)

  Ki-10-I Ki-10-II
Length 7.20 7.55
Wingspan 9.55 10.06
Wing Area 24.39 34.39
Empty Weight Kg 1360 1360
Loaded Weight, Kg 1650 1740 (1883)
Maximum Speed ,kmh 400 400
Service Ceiling, m 10,000 10,000 (9200)
Range, km 1100 1100


Ahead of its time, Richard Vogt’s Ki-5 was the predecessor of the Ki-10.

Ki-10-II undergoing testing at the NII VVS, of its elements of construction
(the stamp on several photos reads “sekretno”).

A Ki-10-I squadron on a Manchurian aerodrome.

Ki-10-I, 1 Sentai, 1938.

Ki-10-I, Manchuria 1939

Ki-10-II of CaptainTateo Kato, 2 HikoDaitai 1938.

Ki-10-II 77 Sentai 1939.