Generally unknown to the outside world, Thailand possesses one of the oldest air forces in the history of military aviation. Its roots go back to February 6, 1911-just seven years after the Wright brothers’ premiere flight-when Charles Van Den Born flew his 37-mph biplane around Bangkok’s Sra Pathum racetrack to the astonishment of an immense crowd. Den Born was among the earliest licensed pilots-the 37th in France; 6th in his native Belgium-and his French Farman IV was the first airplane equipped with ailerons.
Unlike most observers in Europe and America, Siamese Army authorities grasped at once the military potential of manned flight. Just days after Den Born’s exhibition, Prince Chakrabongse Bhuvanath, the Minister of War, dispatched three officers for aeronautic training in France on the 28th. The following November 2, Major Luang Sakdi Salyavudh, Captain Luang Arvudhsikikorn, and Lieutenant Thip Ketudat returned with four Breguet Type R.Uls, three Nieuport IIs, and the ability to fly them. Soon after, Chao Phraya Apai Bhubet (Chum Aphaivong) donated a fourth Breguet to the Ministry of War. With these eight French aircraft, the Ministry of War set up a flight section (“Army Aviation Unit)” in December under the command of General Prince Purachatra Jayakara, Inspector General. Thus, the Royal Aeronautical Service of Siam, as the country was then known, came into being.
The RAS was not a separate air force but organized as a unit of the Army. France’s Breguet had particularly impressed the Thais, because its company president-Henry Breguet-had used this aircraft to successfully complete a pioneer nonstop, cross-country flight from Casablanca to Fes, Morocco, in September 1911. His aesthetically attractive R.U1 may still be seen, suspended from the ceiling of a former church, today’s Musee des Arts et Metiers, in Paris. At 78 mph, the Nieuport monoplane was considered fast for its time. Over the following decades, mostly French aircraft were purchased for the Royal Air Force of Siam.
A favorite was the World War I bomber, Breguet 14, redesignated 14TOE for Theatres Iles Operations Exterieures, exported to Indochina. This version of the big biplane proved so popular with the Thais, they manufactured their own, license-built Breguets throughout the 1920s, when it was to become more numerous than any other type in service. During the next decade, however, French aeronautical development fell behind U.S. and Japanese designs, which became more favored imports. Foremost among them was Mitsubishi’s Ki-21, a large medium-bomber later and better known in the West as “Sally.” Its twin 14-cylinder, Mitsubishi Type 100 Ha-101 radial engines delivered 1,500 hp each to carry a 2,200-pound payload over 1,680 miles at 301 mph, an outstanding performance for 1937. Altogether, 15 Ki-21s were purchased by the Siamese.
The stable Ki-30-another Mitsubishi addition to the Royal Air Force of Siam-was a tough, steady light-bomber with a fixed undercarriage admirably suited for rugged field conditions. The “Nagoya;’ as Thai servicemen referred to it, was moderately fast at 263 mph and could effectively deliver 882 pounds of bombs within a range of 1,066 miles. Its exceptionally long canopy also helped Ann to successfully fulfill reconnaissance missions when and where the exigencies of land warfare demanded. American imports included the ungainly Curtiss BF2C Goshawk, originally designed as a shipboard fighter for the U.S. Navy in early 1933. Irreparable difficulties with its manually operated retractable landing-gear caused withdrawal of the type after just a few months.
Even slower than Mitsubishi’s Nagoya by 38 mph, the Goshawk was unpopular with pilots for its generally sluggish performance, and all specimens were sold off to foreign bidders. Chinese-flown BF2Cs nevertheless scored some “kills” against Imperial Japanese Army aircraft in 1937. Thai pilots found useful the biplane’s capability to carry 500 pounds of droppable stores, but its twin, 7.62-mm Browning machine-guns lacked punch. A better Curtiss design was the almostmodern Hawk 75N. The all-aluminum low-wing monoplane with motorized retractable landing gear was quick at 313 mph, even though its single, 7.62-mm M1919 and one 12.7-mm M2 Browning machine-guns comprised irregular, if scarcely adequate, armament for a fighter of the times.
More abundant were 70 Vought 02U Corsairs, looking every bit their 1927 vintage-“scouts” reminiscent of fugitives from flying circuses or aero squadrons, their tubular steel frames stretched with laminated cloth and braced with wood struts. These open-cockpit biplanes for pilot and observer performed marginally better than their World War I look-a-likes, but the Corsairs obviously belonged to that bygone era. From the same year came Siam’s first aircraft entirely designed and built by Thais, a two-place double-decker christened the Baribatra (after Prince Boripatra Sukumpant, then Minister of Defence) by King Rama VII. A 450-hp Jupiter engine provided the “Bomber Type 2;’ which engaged primarily in goodwill missions to India and throughout French Indochina a maximum speed of 157 mph. Altogether, 12 Baribatras were manufactured.
Two years later, Siam’s second indigenous design appeared in a fighter plane known as the Prajadhipok Its name derived from Phra Bat Somdet Phra Poramintharamaha Prajadhipok Phra Pok Klao Chao Yu Hua, the reigning monarch, more accessible as the Rama VII mentioned above, and mostly notable for having been the only Siamese monarch to abdicate. Although the Prajadhipok’s performance proved no less lackluster than that of its royal namesake, the unremarkable biplane was drafted into service during World War II. The cause of this aircraft’s unwarranted longevity lay in the central problem confronting Thai military aviation; namely, an almost complete reliance on outside sources for equipment abetted by a perpetual scarcity of spare parts. Both the Baribatra bomber and Prajadhipok fighter represented attempts at breaking free from such foreign dependence.
Thai naval aviation began in 1935 with the purchase of two 1,400-ton corvettes from Japan. TheMaeklongand Tachin were each equipped with a Nakajima E4N2 Type 90-2-2 shipboard spotter aircraft. Launched by catapult, the single-float seaplane with twin, wing-mounted outriggers was powered by a 580-hp Nakajima Kotobuki-2, nine-cylinder, radial engine for a cruising speed of just 92 mph over a 633-mile range. Armament for the two-place biplane comprised a fixed, forward-firing, 7.7 mm machine-gun, and one, flexible, 7.7 mm machine-gun in the rear cockpit, plus 66 pounds of bombs. While these characteristics hardly qualified the Nakajima as a high-performance aircraft, it for the first time provided coastal surveillance for the Thai fleet, whose personnel received their flight training from the Royal Siamese Air Force at Don Muang.
Two years later, they were particularly intrigued by a better Japanese spotter plane. The Watanabe E9W1 was something of an innovation, the first successful reconnaissance aircraft designed specifically for operations from a submarine. It was also the first aircraft from Watanabe Tekkojo, the Fukuoka-based Watanabe Ironworks, which went on to build other airplanes throughout World War II and, thereafter, automobiles, until it went out of business as recently as 2001.
While the E9W1’s performance was similar to that of the Nakajima floatplane, it was carried in its own hangar aboard the Imperial Japanese Navy’s largest submarine and could be reassembled and airborne in 2 minutes, 30 seconds. Returning from its mission, personnel dismantled the Watanabe and stowed it away one minute faster. The 372-footlong J3 type submarine from which it operated displaced 2,919 tons, was staffed by 114 crew members, and capable of extended voyages over 16,000 nautical miles at 16 knots.
The Royal Siamese Navy possessed four submarines, but none were capacious enough to store an E9W1, which the Thais envisioned for surface warships, despite some misgivings regarding the aircraft’s less-than-forgiving handling properties. Accordingly, they ordered their own tailor-made version-the WS-103 “S” for “Siam”-from Watanabe, which began production during November 1937.
The first specimen completed its maiden flight in February 1938 to the satisfaction of Siamese naval officers, who took charge of six initial examples the following May. Wings and fuselage were extended for improved stability, and they featured more powerful armament: three Madsen 8-mm machine-guns, one in the fuselage and two mounted in the upper wing, with an additional 7.7-mm machine-gun operated by the observer. The Thai reconnaissance plane was also equipped with a short-wave radio, and some versions had a set of dual controls for use as advanced trainers.
While the WS-103 “S” represented a thoroughly modern, even ultramodern concept, the Royal Siamese Air Force more often had to make do with outdated equipment. Recently turned obsolete was the formerly cutting-edge Martin B-10, enabled by its twin, 755-hp Wright R-182033 (G-102) Cyclone radial engines to outrun every pursuit plane at 213 mph when introduced in 1934, since overtaken by interceptor development, but still capable of carrying 2,260 pounds of bombs. Siam’s Royal Air Force received six of these rapidly aging medium-bombers in 1937. On April 12 of that year, the Army relinquished its hold on the Royal Aeronautical Service, allowing it to become an independent branch of the armed forces, the Kong 7hab Akat Thai (KTAT), or Royal Thai Air Force, as it was henceforward known.
Two years later, “Siam” changed its name to “Thailand;’ a fundamental transformation coinciding with the eruption of war on the other side of the world. German triumph in the West during June 1940 spawned a collaborative French government Thai leaders hoped would be more amenable than past regimes to the uneasy independence of their country. It had been surrounded on almost all sides since 1900 by a single, large colony comprising Cambodia, Laos, and Vietnam. Referred to by outsiders as Indochina, it encompassed 289,577 square miles with a population of 21,599,582. Not content with this vast “protectorate;’ the French began adding to it by laying claims to additional slices of western Siam, which had so far escaped absorption into the imperialist amoeba.
The alarming seizure of these territories had been duly brought to the notice of the League of Nations, whose delegates offered sympathy, but nothing else, in deference to France, then regarded by anti-Nazis everywhere as Hitler’s most effective nemesis, and, therefore, not to be antagonized over distant, colonial quibbles. Hence, the political backdrop for the buildup of Siam’s armed forces and its growing alignment with Imperial Japan.
Thailand’s own Prime Minister Phibun Songkhram, more popularly known as Marshal Phibun, was himself pro-Fascist, and anticipated some kind of mutually amiable accommodation with the new Vichy government. Diplomats on both sides pursued negotiable solutions throughout the summer of 1940, but the French only implied that some minor concessions might be made in the future. By late autumn, further talks appeared fruitless, and Marshal Phibun decided on military action.
His goals were strictly limited to restoring lost areas of Thailand, not expulsion of the foreigners from Southeast Asia. On the contrary, he admired the French and regarded the preservation of their status quo in Indochina as a powerfully civilizing influence. Phibun’s armed forces had been nevertheless preparing for the eventuality of such a campaign since he became Prime Minister in 1932. His 60,000 soldiers were organized into four armies, the largest one being the Burapha Army, which was made up of five divisions supported by a signal’s battalion and one engineer battalion, plus an artillery battalion equipped with more World War I German Krupp field guns than modern British Bofor howitzers.
Standing against these formidable ground forces was a colonial army of 50,000 men, but only 12,000 thousand of them were French. The rest were more or less reliable Cambodians, Laotians, and Vietnamese organized into 41 infantry battalions, two artillery regiments, and a battalion of engineers. While the French tanks were no less antiquated than those operated by their opponents, only 20 5.6-ton Renault FT17s, with 37-mm cannon or 7.92-mm machine-gun, faced 60 1.5-ton Carden Loyd T-27 tankettes and 30 16-ton Vickers A6 medium tanks of the Royal Thai Army’s two motorized cavalry battalions and one armored regiment. Britain’s A6 mounted a three-pounder cannon, but the little tankette fired only one .303-inch machine-gun.
The Armee de /Air was less disadvantaged. It counted somewhat less than 100 machines against 5 air wings of 140 warplanes flown by the Royal Thai Air Force, but its crews were better trained and experienced and its aircraft more modern. The finest fighter in Indochina at the time was the twin-engine Potez 630, although the French possessed them in numbers too small to make much of a difference in any major confrontation with the Thai. A distant second was the admittedly substandard but more plentiful Morane-Saulnier M.S.406.
Far less up to date were four Farman 221s, each powered by quartets of 950-hp Gnome-Rhone 14N, radial engines-two pushing and two pulling-in pairs of nacelles slung under an 188-foot wingspread. The ungainly heavy-bomber was inadequately defended by just three, 7.5mm MAC 1934 machine-guns from dorsal and ventral positions and in a bulbous nose turret, but it could carry 9,240 pounds of pounds over 1,245 miles if unmolested by interceptors or accurate ground fire.
Also on hand were 30 Potez 25 TOE sesquiplane fighter-bombers comparable to World War I predecessors, eight Loire 130 flying boats, and several examples of the Breguet 19 and 27, vulnerable reconnaissance biplanes. Other machines at the Armee de /Air’s disposal were six half-wood-and-aluminum Potez 542 high-wing monoplanes of questionable utility.
Hostilities opened in an aerial campaign when several doddering Vought Corsairs attacked a French patrol ship on December 1, 1940. The Beryl had violated Thai sovereignty by cruising off the Cambodian coast. She not only escaped all 14 bombs hurled at her by the attackers, but claimed one of the 02Us with her antiaircraft guns. Eight days later, a Corsair scored the conflict’s first aerial victory by destroying a Potez observation plane scouting for the French. Another Thai OSU was lost, however, on the 9th, when it was brought down by return fire from a Loire 130. The gunners aboard this particular flying boat proved their exceptional accuracy again on December 12 by knocking another enemy interceptor out of the sky, this one a wholly superior Curtiss Hawk from the Thai’s 70 Squadron.
Marshal Phibun had hoped that the French might be persuaded to relinquish their hold on occupied Thai territory after administering a few, powerful blows. But the disappointing performance of his pilots paralleled events on the ground, and he resigned himself to a longer struggle with an official declaration of war on December 24. After a two-week mobilization period, he ordered the Burapha and Isan Armies to launch joint offensives in early January 1941 against Laos, which was quickly overrun, and Cambodia, where French resistance was heavy.
The Kong Thab Akat Thai meanwhile carried out its first official operation on January 7, when 23 Mitsubishis blasted French targets across Cambodia. The following day, three Curtiss Hawks escorted nine Ki-30 bombers in a raid against the French airfield at Siem Reap. In a daring low-level run, five Thai Goshawks braved heavy concentrated ack-ack to shoot up a line of valuable Potez 630 fighters parked in the open.
Beginning on the 9th, and over the next 48 hours, more Thai warplanes engaged in daylight attacks against the cities of Battambang, Sisofon, Vientiane, and Pakse. Only now did the Armee de lAir make its appearance in the form of a Morane-Saulnier fighter piloted by Captain Tivoliere. He avoided Sergeant Boon Suksabi’s rearward-facing 7.7-mm machine-gun by climbing up from beneath the Nagoya and blasting its 14-cylinder Nakajima Ha-5 kai radial engine. Suksabi and pilot Boonyam Bansuksawat were the first KTAT airmen killed in action, when their Ki-30 crashed and burned near Sisofon.
During the early morning hours of January 10, an antiquated Breguet-19 reconnaissance plane ominously soloed over the Thai capital. By early afternoon, the French struck Bangkok in force. Potez 25 sesquiplanes and Farman heavy-bombers were accompanied by every other aircraft capable of carrying even the smallest payload in an all-out attempt to incinerate the city, built mostly of wood structures. Due to a total lack of any advance warning system, KTAT commanders were taken unaware, and failed to scramble a single fighter, while Thai antiaircraft batteries missed all their targets. The French were far more accurate, creating major damage that left Bangkok in flames. Only a concerted effort undertaken by fire-brigades with the assistance of virtually the entire civilian population prevented complete destruction.
The next day, motivated crews of the Royal Thai Air Force responded by striking the Nakorn-Bat airfield near Siem Reap, where the Farmans were based. The first incoming wave of Vought fighters was intercepted by Moranes of Escadrille 2/595, which shot down two Corsairs in quick succession. Hard on their heels came nine Mitsubishi bombers protected by four Curtiss Hawks. Lieutenant Labussiere halved the number of escorts by scoring a pair of “kills” against them, while Captain Tivoliere-the same pilot who scored the first French aerial victory of the war during the previous day-claimed a Ki-21. Undeterred by these sudden losses, the Thai airmen pressed their attack. A Morane fell in flames under the guns of Sergeant Sangvan, just as Warrant Officer Tongkam destroyed another M.S.406. Labussiere was himself wounded and his aircraft set on fire by Sergeant Blengkam’s accurate marksmanship, but the French pilot escaped with his life from a crash landing.
During this ferocious air battle, French ground crews at NakornBat frantically manhandled most of their heavy-bombers into sheltering caverns used as natural hangars. Before the last big Farman could be moved, however, it was set upon by a trio of Mitsubishis and blown to bits. The other five Ki-21s blasted an antiaircraft battery and cratered the airstrip, rendering it temporarily inoperable. KTAT vengeance resumed on the 15th, when a Martin bomber and five Curtiss Goshawks surprised enemy warplanes on the ground at the Dong Hene airfield. The raiders escaped without loss, leaving behind a pair of Potez 25 TOE bombers and two Morane fighters on the ground in flames, plus a control tower reduced to ruins.
Japanese Aircraft in Royal Thai Air Force and Royal Thai Navy Service During World War II