History of Japanese Fighter in RTAF and RTN


RTAF Nakajima Ki-27 Otsu

RTAF Nakajima Ki-27 Otsu


You would be a bit surprised if you heard that Royal Thai Air Force used to fly the Japanese-made fighter aircraft!

It began during the WWII, when the Imperial Japanese Army (IJA) moved into Thailand as a route to enter Burma. Thailand and Japan later signed an alliance treaty and Thailand also declared the war against the allied force.

During that time Royal Thai Air Force, (RTAF) is the second largest air force in Asia with the total strength of more than 200 fighter aircrafts but American-made Curtiss Hawk or SPAD proved obsolete compare to the mighty Japanese. On the day IJA enters Thailand, even IJA force suffered the most lost in the opening day at pacific, Thai armed force still could not held on.

After the alliance treaty was signed, Japan started to modernize its ally by offer its Japanese designed fighter aircraft. 12 ‘Nakajima Ki-27s’ were bought to equip RTAF fighter squadrons in 1942. (RTAF designation is Fighter Type 12th) Ki-27 is the primary fighter of Imperial Japanese Army Air Force, IJAAF. Allied Force called it ‘Nate’ but RTAF often called it Otsu. Another alias is ‘Sparrow’ due to its small-but-agility characteristic.

One of the most famous air combat of RTAF Ki-27 is “5 vs. 21 dogfights”. It began when 5 Ki-27s of 16th fighter squadron of 85th joint air wings in Lam Pang scrambled to intercept P-51 Mustang and P-38 Lighting from 447th fighter squadron, 14th Air Force, United States Air Force (USAF) in China. All Ki-27s were shot down but managed to bring down 4 P-51s. Later confirmation from USAF told that there were only 8 P-51s and 9 P-38s participated in the battle. One P-51 was downed and some other aircrafts were damaged.

RTAF Nakajima Ki-43 Hayabusa

RTAF Nakajima Ki-43 Hayabusa

Another Japanese fighter who made their way into RTAF is ‘Nakajima Ki-43 Hayabusa’. (RTAF designation is Fighter Type 13th) The first batch of 18 Ki-43s was supplied to RTAF for free in 1943. Another was delivered in the same year when Japanese then Prime Minister Hideki Tojo visited the Grand Palace in Bangkok. The book ‘Buddhist Commander – The Memory of General Nakamura about Thailand during the Greater East Asia War’ wrote by General Aketo Nakamura, Commander of IJA in Thailand captured the moment ….

“…. On 3 July 1943, PM Tojo visited Thailand and Grand Palace. He was very impressed by the elegant and magnificent architecture of the temple. He turned his face to me and says ‘This temple is the greatest eastern culture heritage and a precious treasure. We should station Anti-Aircraft Artillery to defense them.’ I quickly replied that ‘Sir, I have only a platoon of Anti-Aircraft Artillery and when we combine with the small amount of the Thais. We have a duty to defense Bangkok. If the enemy aircraft attack us we do not have a single fighter to fight them’. I gave my worry to him. He didn’t say more and so did I. But soon after PM Tojo went back to Japan I received good news that he sent 21 Hayabusa fighter aircrafts for Thai Air Force. I thank you him with my heart and the Thais are very happy too ….. ”.

All 39 Ki-43s proved to be the backbone of RTAF. In the most famous mission is on 29 November 1944 when Flight Lieutenant Terdsak Vorasap and his brother pilot scramble 7 Ki-43s to intercept 50 B-29s from USAF that about to bomb Bangkok. He managed to shot down one B-29, make him become the first man in the world who could bring down this Superfortress.

Nakajima Ki-43 Hayabusa in the air battle with B-29

Nakajima Ki-43 Hayabusa in the air battle with B-29




Not only fighter, in 1940 RTAF bought 24 ‘Mitsubishi Ki-30s Nagoya’ strike aircraft. (RTAF designation is Attacker Type 2nd) The nickname ‘Nagoya’ was derived from the Japanese city that these aircraft were build. RTAF used this attacker in the Thai-French Indochina war in the beginning of WWII. Ki-30s successfully conducted several of strike missions in the French-colony Phra Tabong province which is now the part of Cambodia.


RTAF Mitsubishi Ki-30s Nagoya

RTAF Mitsubishi Ki-30s Nagoya




At the peak of the war, RTAF also received 10 Nakajima Ki-21s Bomber to equip the bomber squadron. (RTAF designation is Bomber Type 4th). Ki-21s were seen mostly in bombing mission Shan state, Burma. Also RTAF trained its pilot in Tachikawa Ki-36.Royal Thai Navy (RTN) also operated some Japanese aircrafts. 6 Watanabe WS-103S (RTN designation is RTN 1) were bought and become Thailand first seaplane. Another two is 27 Mitsubishi F1Ms and 3 Aichi E13As. (RTN designation is RTN 2 and RTN 3)  All these reconnaissance planes were helped establishing a Royal Thai Navy Air Arm. 

Japanese aircraft were seen in operational for only around 5 years.  After WWII was ended and US approval of the Thailand’s declaration of war is never in effective so Thailand will not loose the war, US request Thailand along with all Asian countries and territories to destroy all Japanese military equipments. RTAF fighter is not an exception even RTAF want to put them in museum. So we can not see the evident of the glory day of Japanese fighter in Thailand. Only one aircraft could manage to survive is Ki-36s that store in RTAF museum in Don Muang Air Force Base. This is one of the only two examples left in the world. (Another aircraft is in China)

RTAF Tachikawa Ki-36

RTAF Tachikawa Ki-36


Today, Thailand and Japan continue to build a close relationship between its armed units. Every year, RTN cadet will receive a scholarship to study in Japan Maritime Self Defense Force Academy. Japan is the familiar face in Cobra Gold, region finest and largest military exercise. This is surely base on the long relationship from Ayutthaya period to the WWII and surely to tomorrow.


RTN Watanabe WS-103S

RTN Watanabe WS-103S


Wings of Siam http://wingsofsiam.pantown.com
Skyman Military Blog http://skyman.bloggang.com
RTAF Aircraft Category http://www.dmbcrtaf.thaigov.net/aircraft/aircraft.html
Wikipedia http://en.wikipedia.org
Royal Thai Navy Air Division http://www.navy.mi.th/flynavy/


3 Responses to History of Japanese Fighter in RTAF and RTN

  1. PeterS says:

    I think Thailand was very lucky that the US “destroyed” the declaration of war.

  2. thaimilitary says:

    Yes. It’s funny do you think? You joint the Japanese but you didn’t lost the war. UK want to put Thailand as a looser but US do not agree. We must say thank to the American for their help at that time. Also thank the Free Thai crop who keep contact with the allied all the time during the war. This is one of the keypoint in Thailand history.^ ^

  3. William Elmore says:

    I am researching information for a book tentatively titled “Combat Biplanes in World War II.” I have identified 130 such types of airplanes including the Watanabe WS-103 which appears to have been the most obscure such airplane. I have been able to put together a fairly good history of the airplane but the specifications of the airplane – such as wing span, length, weights, performance, etc. – seem to be non-existant. l know of no publication or internet site that contains this information. Could you possibly forward what I seek?

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