Curtiss Hawk 75A/Mohawk. Part Six. The Curtiss 75 Hawk in China.

 

The Curtiss Model 75H was a simplified export variant of the Curtiss Model 75 fighter built with fixed landing gear, powered by a Wright GR-1820 radial engine rated at 875 hp. It was used as a demonstrator for various countries, among them, China.
The first Model 75H was completed in June 1937 and was soon shipped to China. On 25th August 1937 it was shown in Nanjing where, Madame Soong Mei-Ling, General Secretary of the Aviation Commission for the Kuomintang Government acquired the demonstrator for $35,000 of the time and gifted it to Colonel Claire Chennault, back then, advisor to the Republic of China Air Force (ROCAF). The Model 75H was interesting for the ROCAF as it was powered by the same engine that the Curtiss Hawk III biplane, the backbone of ROCAF fighter force, so it was familiar to both pilots and ground crew.
After having acquired the aircraft Chennault instructed American technicians to install weapons on the 75H, including one .5-caliber and one .3-inch machine gun in the nose, and one .3-inch fixed machine gun on each wing. He also invited his colleagues Billy McDonald and John Williamson as well as Col. Mao Bangchu and Major Huang Panyang from China to train on the aircraft. 
Apparently, during the Battle of Shanghai Chennault himself flew the 75H on many reconnaissance flights, witnessing various stages of that battle. After the fall of Shanghai, the 75H was passed on to the leader of ROCAF's 17th Squadron, Huang Panyang who also employed the type for recon duties. Later it was passed on to 25th Squadron on 7th May 1938, where its leader Tang Busheng flew it too. During this time, the 75H was flown to Nanjing, under heavy Japanese anti-air fire and, when approaching to its homebase, it suffered a spin when landing, causing several damage beyond repair.

In September 1937, two weeks after the demonstration flight of the 75H, the Chinese Government ordered from Curtiss thirty Model 68 Hawk III biplanes and thirty Model 75M, which was the mass-production variant of the 75H having also a fixed landing gear. Those sixty aircraft arrived disassembled in Guangzhou during the early summer of 1938 and on 9th July 1938 the 25th Squadron received its first 75M in Hengyuang, province of Hunan, under the guidance of Chief Advisor Chennault.
The whole squadron was not fully equipped with the 75M until 5th August 1938. 
It was then discovered that those aircraft were shipped directly from the United States without test flights and they were 20 mph (32 km/h) slower than expected. They were also prone to suffer many mechanical failures. Curtiss urgently dispatched an investigation team to China to handle the situation, which reached to the conclusion that the fighters were in perfect conditions and it was ground personnel's fault for not following maintenance procedures, specially on the mechanical maintenance section, as they did not have good understanding of the functions of the aircraft's components and lacked technical skills.
On 18th August 1938 a force consisting on 27 Japanese fighters attacked Hengyuang and Sqd. Ldr. Tang Busheng faced the enemy with a force consisting on three 75M and seven Polikarpov I-152. During the ensuing fight one 75M was shot down with another one damaged. Sqn. Ldr. Tang was killed in action and the other two 75M were forced to land.
On 24th August the 25th Squadron was rebased to Liuzhou, in the province of Guangxi. Later, on 18th September twenty-four Japanese bombers escorted by a force of twenty-two fighters bombed Liuzhou, destroying one 75M, causing the 25th Squadron to be rebased again, this time to Zhijiang in Hunan. 
From Zhijiang both 25th and 16th Squadrons (this last one was recently equipped with the 75M) performed joint training under Chennault supervision. Later on 7th and 8th November thirty-six Japanese aircraft attacked Hengyand Zhijiang with both squadrons dispatching a total of eight 75Ms to engage them. During this battle two Japanese aircraft were shot down and another one was damaged, with one 75M being destroyed on the ground. 
On 11th January 1939, Sqn. Ldr. Liu Yijun, deputy leader Zhang Mufei , Sqn. Ldr. Zhang Xuecheng, Mu Yuwen and Zhang Yaonan flew five 75M to Chongqing, province of Sichuan, where the 75M were handed over to the 18th Squadron, however, on the return trip the transport where those pilots were travelling back crashed killing all the officers. As a result, both 25th and 16th squadrons were short on personnel and equipment and had to be disbanded. 
After the fall of Wuhan in October 1938, Hengyang was in range of Japanese bombers so it suffered frequent aerial attacks. That's why 16th Squadron, which was recently equipped with the 75M, and under command of Cpt. Yang Hongding, was transferred to Zhijiang. After completing joint training, it was transferred to Yibin, Sichuan during early 1939 to provide aerial defence in Chongqing, the wartime capital of the Republic of China back then. In June 1938 every aircraft and some personnel of 16th squadron was merged into 18th Squadron with the 16th being officially disbanded in August. The 18th squadron was officially established in November 1938, with Cpt. Yang Yibai in command. In January 1939 the unit was transferred to Kunming, province of Yunnan for advanced training and provide aerial defence of the city. In April they took part in the interception of enemy aircraft by a mixed formation led by Hu Zhuangru, the officer academy's fighter squadron leader. In May they were transferred back to Yibin to serve in the night-fighter role in Chongqing. In December 1939 they took part in the Guinan campaign and from January to May 1940 they served as aerial defence alerts in the Kunming area to protect the important Yunnan-Indochina railway. In June 1940 they returned to Chongqing to, once again, protect the capital and serve in aerial defence operations between Chengdu and Chongqing until the end of 1940. 
Shortly after the squadron was disbanded too. The remaining aircraft were transferred to the 11th Squadron, dedicated to the training role in January 1941. 
It was during this year that the remaining units of the ROCAF went to India to receive aircraft provided by the United States. The 75Ms were handed over to the 3rd Squadron, which remained in Chengdu. By 1942 a small number of 75Ms were still in service. Among them at least two were provided by the American personnel who were present in China at the time when the B-25 Mitchell bombers belonging to the famous Doolittle Raid made an emergency landing.

There was another variant that served in China, the Hawk 75Q. This variant featured a retractable undercarriage and was armed with one .5-inch and one .3-inch machine gun in the nose, plus two 23mm Danish-made Madsen cannons in the wings, similar to both the XP-36F and the Hawk 75A-5. It was shipped together with a Curtiss CW-21 light fighter to CAMCO's (China Aircraft Manufacturing Company) facilities in Leiyun, province of Yunnan to be assembled. 
After flight tests it was flown to Chengdu to take part in mock aerial dogfights against the Soviet-made Polikarpov I-153 and I-16 of the ROCAF, proving the 75Q to be superior to both. 
After those testing additional components of the 75A-5 were delivered to Leiyun but they were soon evacuated to Bangalore, India, due to Japanese bombing and their advancing army. 
There, they were handed to Hindustan Aircraft, where they were completed. 
For more information about their fate, check out our previous post about Asian users of the Curtiss Hawk 75.

Sources:
1st https://cwlam2000.epizy.com/caf35.htm (translated and adapted)
2nd  AJ-Press - Monografie Lotnicze 61 - Curtiss P-36 Hawk Part 1 (translated)
3rd https://en.wikipedia.org/wiki/Curtiss_P-36_Hawk

Boeing Stearman Model 75, part three. The Stearman in Asia.

 

The Boeing-Stearman Model 75 is an American biplane-two seater trainer of the 1930s that was employed all around the world in various countries, among the following Asiatic ones:

• China: In 1942 the United States sold China 150 Boeing-Stearman PT-17 primary trainer (Model A75L5) under the Lend-Lease programme. They were to serve in the trainer role at the Kuomintang Air Force School which was moved to the Lak River airport in Punjab, India (actually the closest military installation of the time that we could find there was RAF Lahore).
  After the end of World War 2, in 1946, the Chinese PT-17s flew over the so-called 'Hump Route' (the Himalayas) and returned to Chinese soil to serve as trainers for students at the Jiangqiao Aviation School. 
  In 1947 the Republic of China Air Force (ROCAF) bought twenty-two additional A75L5s, the first two of which were powered by the Lycoming O-435-11 engine which was considered unsuitable by Boeing due to their lack of horsepower. The ROCAF agreed that the remaining 20 aircraft would be powered by the Continental R-680-4 radial engine which yielded 220 hp of power. 
  Mister Yun Duo, who was the director of the Kuomintang Air Force's Third Aircraft Factory located at Taichung, Taiwan, copied the design of the PT-17 in 1947. 
  This copy was commonly known as CJ-1 (from Chinese 'Chū jiào' - meaning 'Primary Trainer-). These CJ-1s were made out of surplus American material left over by the Americans in Taiwan and they were powered by the Continental engine.
  The CJ-1 flew officially for the first time in February 1948 and was quickly followed by a rapid and steady mass production system, where production was supervised by ROCAF's officials.
  A total of 104 CJ-1s were manufactured and sent to various academies on Chinese mainland, most of which were sent back to Taiwan in 1949 when the Kuomintang evacuated to Taiwan and most of the CJ-1s -and surviving PT-17s- were assigned to the Gangshan Air Force Academy to serve as primary trainers. They remained there until 1958 when they were withdrawn from ROCAF's inventory.
  On the other side, it is known that at least one PT-17 was in service with the People's Liberation Army Air Force at Jiangqiao in 1950, but further details are unknown.
  
  
• Iran: According to some sources, the PT-17 was also employed by the Imperial Iranian Air Force in the 1950s, however we couldn't find any reliable source, so the drawing should be considered as speculative.
  
  
• Philippines: In 1937 (though some sources claim it was one year before or even later), the Philippine Army Air Corps (PAAC) acquired an unknown number of the Stearman Model 73L-1 and L-3 (of which a total of 10 machines were manufactured) and 27 Stearman Model 76D-1 and D-3s (AKA BT-1) which makes a total of 37 Stearmans serving with the PAAC.
  This version was armed, as it was equipped with a defensive machine gun at the observer's position and had provision to carry small bombs under the fuselage. In 1941 they were know to be in service with the 1st (School) Squadron at Zablán Field and the 7th Squadron, at Maniquis Field, of the PAAC, however, given the situation of the PAAC, they were very unlikely to have seen any action when Japan invaded the Philippines in December 1941.
  After World War 2, in 1947 with the creation of the Philippine Air Force (PAF), many PT-17s  were acquired to serve at the PAF's school and even some surviving Model 73s were put into service with that same school. They were kept in service until the mid-to-late 1950s.

Sources:

1st en.wikipedia.org/wiki/Boeing-Stearman_Model_75

2nd http://cwlam2000.epizy.com/cafx82.htm (translated)

3rd http://www.stearman.at/boeing_stearman_technical_data.html

Tupolev SB in service with China

 

On 7th July 1937 Japan invaded China sparkling the Second Sino-Japanese War. The Chinese Air Force (CAF) had, at that time just 284 aircraft and was commanded by General Moa Pang-chu who had learned to fly in the USSR. 

On 21st August both China and the USSR signed a non aggression pact, by virtue of which a secret clause was included to send military aid to China. This clause stressed on rebuilding the virtually destroyed Chinese Air Force. The Chinese negotiated a major loan with the USSR to provide China with war materials in exchange for cheap raw resources over the next five years.

During the course of October 1937,  four hundred fifty Soviet pilots and technicians were gathered at Alma Ata (Kazakh SSSR - nowadays Kazakhstan) from where they departed with a first batch of 185 aircraft (115 fighters, 62 bombers and 8 advanced trainers). These aircraft were transported by rail from Alma Ata to Lanzhou (province of Gansu) , where the Chinese railroad ended, following the trace of the old Silk Road. 

Chinese SB 2M-100-As (with old style cowlings) were all built at the GAZ factory No. 125 Imeni Stalina located at Irkutsk, in Siberia. Soviet pilots collected the first batch of bombers from the factory and ferried them from Irkutsk to Suzhou (in Gansu too) via Ulan Bator, Mongolia. Due to a sandstorm, the aircraft had to be grounded for a short time, before resuming the flight from Suzhou to Lanzhou. Many Soviet advisors began to train Chinese crews assigned to the 2nd Group of the CAF, on the SB 2M-100A. The first combat mission was led by Cpt. I.N. Kozlov on 2nd December 1937, when nine SBs attacked Japanese shipping in the East China Sea off the coast of Shanghai. 

A second batch of 31 SB 2M-100A was led by Cpt. Fiodor P. Polynin. These machines were ferried from Irkutsk to Hankou with stopovers at Ürümqi (Xinjiang), Hami (Xinjiang) and Lanzhou. The bombers were manned by Soviet crews until the Chinese were able to master the aircraft. A total of 150 sorties were flown by Soviet volunteers against Japanese airfields, riverine traffic and communications centers during the months of January and February 1938. One such mission took place on 25th January 1938 when 13 SB 2M-100A attacked the Japanese airfield at Nanjing (Jiangsu). 

On 23rd February Cpt. Polynin led a force composed of 28 SB 2M-100As to attack the airfield of Hsinchu, at north-western Formosa (Taiwan). The bombers were armed with ten bombs each and flew most of the distance from Lanzhou to Formosa across it straight at 5.500 m (18.045 ft) of altitude, causing headaches to crew members due to the lack of oxygen. In spite of this problem, the SBs approached Hsinchu from the north achieving total surprise when they dropped their bombs. Japanese anti-air fire proved ineffective and no Japanese fighters were put in the air to intercept the bombers. The SBs arrived back at Lanzhou without any incident after a seven-hour mission. Madame Chiang kai-shek, wife of the Chinese leader, rewarded the Soviet airmen with a banquet and decorations.

All those previously mentioned missions were flown without fighter escort, as the SB 2M-100A was the fastest bomber present on both sides of the Second Sino-Japanese War. These bombers suffered relatively low losses during combat and the biggest threat to them were Japanese raids on SB airfields.

A third Soviet bomber group (the exact number of flown aircraft is unknown) led by Georgy I. Tkhor left GAZ 125 at Irkutsk in late April 1938 and ferried to Lanzhou, this time via Ulan Bator and Dalanzadgad (Mongolia). This group took also part in many missions against the Japanese between the months of June and October 1938.

In late 1939 several SB 2M-103 were also supplied to the CAF. It was at this time when Soviet volunteer airmen began to leave China, as the Soviets became disillusioned and frustrated in spite of the fact that Soviet aid help to strength Chinese resistance against the Japanese. The Soviet aircraft were often misused and crashed when manned by Chinese crews as they lacked experience and therefore didn't follow (or didn't understand) Soviet instructions. The Chinese put the SBs in reserve, instead of flying them into combat.

On 27th December 1939 three SB M-103 of the last Soviet volunteer unit at Hengyang (province of Hunan) flew southwest to support Chinese ground troops at the Battle of Kunlun Pass. They were escorted by the last Gloster Gladiator fighters of 28th Squadron. After the Soviet withdrawal the remaining SB 2M-103s were assigned to the 1st and 2nd Groups of the CAF.

In 1940 a single Tupolev SB constituted the only offensive aircraft the Collaborationist Chinese Army Air Force (CCAAF - AKA Peacebuilding National Army) had. It was joined in September by another SB, piloted by Cpt. Zhang Diqin and manned by Lts. Tang Houlian and Liang Wenhua who defected to Nanjing, and were given substantial reward by the Japanese.

Chinese-manned SBs suffered heavy losses against experimented Japanese pilots. The USSR supplied 100 SB 2M-03 (including some SB 2M-105 -which was one of the last production variant-) in early 1941. These replaced some of the aircraft lost the previous years to accidents and combat. China became the largest foreign user of the SB with a total of 392 aircraft delivered straight from Soviet production lines. On 13th April 1941 Stalin and Japanese foreign minister Yosuke Matsuoka signed a neutrality pact. This resulted in a swift halt in the deliverance of Soviet war material to China, but the SBs were allowed to remain in CAF service. A formation of three SB 2M-103s made three attacks on Japanese troops crossing Dongting Lake (Hunan) and raided Yichang (province of Hubei) in September 1941. 

Chinese SB 2M-103 served well into 1943 and, in some missions, they were escorted by the Curtiss P-40 of the American Volunteer Group, the famous Flying Tigers.

Apparently some few SB survived World War 2 and took part, albeit in limited number and usage, in the last stage of the Chinese Civil War (1945-1949). 

Sources:

Sources:

1st Signal Squadron - Aircraft In action 194 - Tupolev SB in Action

2nd https://en.wikipedia.org/wiki/Tupolev_SB

3rd https://massimotessitori.altervista.org/sovietwarplanes/pages/sb/tapani/chinese/chinese.htm

Junkers Ju.52/3m Various African, Asian & Oceanian Users

 

The Junkers Ju.52/3m was probably the most used German cargo plane in the whole World War 2. Given its versatility, manoeuvrability and handling easiness it attracted many contractors and was widely exported, all around the globe to, among many others, the following countries:

• Australia: The Royal Australian Air Force (RAAF) operated a captured Ju.52/3mg7e which was left abandoned by the retreating Germans in North Africa. It was assigned to the No.450 Squadron RAAF, was repainted in Commonwealth desert colours received the nickname of "Libyan Clipper". It was used as a cargo to transport mail, food, supplies and other types of goods from Cairo and back to the frontlines, performing two or three flights per week. It was also used by Lord Casey, Governor General of Australia to visit the men of the No.450 Squadron in 1943. The fate of the aircraft is not known.
• Belgian Congo: After the fall of Belgium in spring 1940, SABENA (Belgian national airline) continued its African operations in the Belgian Congo, as they had some Ju.52/3m stationed there from before the War. Their operations continued normally inside the Belgian colony and, in many cases they were used as cargo flights in the region for the Allies. SABENA kept their Ju.52/3m in that region until 1946 when they were replaced by the Douglas DC-3.
• Republic of China: Eurasia Aviation Corporation was China's national airline which, although its headquarters were located in Shanghai, its main operation hub was located in Hong Kong. It was founded in 1925 and ten years later, in 1935 they acquired three Ju.52/3m which were the main aircraft of the airline. When the Japanese occupied large portions of China in the mid-1930s, the airline had to cope with many difficulties. One of them was Chiang Kai Shek's personnal airplane. On 7th December 1941 all three of them were parked at Kai Tek airfield, in Hong Kong and were destroyed by Japanese Tachikawa Ki-36 attack bombers.
• Iraq: When the Luftwaffe created the Fliegerführer Irak in May 1941 to assist the regime of Rashid Ali in their war against the British, thirteen Ju.52/3m were assigned to perform transport tasks, however, all but three of them had to return to Greece to prepare the Invasion of Crete. 
  By May 15th there were three Ju.52/3m and two days later, just two. The whole Fliegerführer Irak left the country on 29th May.
• Territory of New Guinea: Between 1955 and 1959, Gibbes Sepik Airways, an airline that operated in New Guinea, bought three Ju.52/3m from Sweden. These aircraft were re-engined with the Pratt & Whitney R-1340 Wasp engine and drove three-bladed propellers. This airline was purchased by Mandated airlines in 1959 and kept the Ju.52/3m in service covering some interal aerial routes until April 1960 when they were written off.

Sources:

1. https://en.wikipedia.org/wiki/List_of_Junkers_Ju_52_operators

2. https://www.awm.gov.au/collection/C957275

3. http://www.adf-serials.com.au/junkers52.htm

4. https://en.wikipedia.org/wiki/Sabena

5. https://en.wikipedia.org/wiki/Eurasia_Aviation_Corporation

6. https://en.wikipedia.org/wiki/Fliegerführer_Irak

7. https://www.goodall.com.au/australian-aviation/junkers%20ju52/junkersju52.html

Mitsubishi A6M 'Zero', part one, foreign users

The Mitsubishi A6M 'Zero' is a Japanese long-range fighter which was manufactured by Mitsubishi Heavy Industries, in Nagoya, Japan. It's considered to have been one of the most capable carrier fighters in the world when it was introduced back in World War II as it had excellent speed ,manoeuvrability and very long range. It was used by many foreign n/ations, albeit every foreign user employed captured exemplars.

• Australia: At the end of the war, a single Zero was given by the TAIU-SWPA (Technical Air Intelligence Unit - South-Western Pacific)  to the No.457 Squadron, Royal Australian Air Force (RAAF) at Clark Field, in Philippines. It was tested by the RAAF.
• Nationalist China: The Republic of China Air Force (ROCAF) operated some captured Zeroes of every variant, A6M2, A6M3 and A6M5 mainly. Most of them were captured after the when war, when the Japanese left China, as most of them belonged to the Japanese 12th, 13th, 14th, 15th and Shanghai Kokutais (Air Groups) which operated from mainland China. They were also part of the Imperial Japanese Air Service's (IJNAS) detachment stationed in Formosa, which were Hao Toko, Takao, Tetshu, Kagi, Toki and Tainan Kokutai. During the last stages of the Chinese Civil War, from 1945 to 1949, the Zeroes were employed by both sides, Communists and Nationalists, but neither of them survived the war or those which did, were scrapped shortly later.
• United Kingdom: Some Zeroes were tested by the ATAIU-SEA (Allied Technical Air Intelligence Unite - South East Asia) after the war. One of them, re-registered as Bi-12 was captured in Malaya and was tested at Tebrau airfield, in Malaya in 1946. However, it seems that most of them  were tested at RAF Seletar, in Singapore.
• Soviet Union: When the USSR took the Sakhalin islands, apparently they captured some Zeroes, of the A6M7 Model 63 variant, which was the last variant to see service. This variant was more focused on ground attack/dive bombing. When it was flown by the Soviet VVS (Soviet Air Force) after the war, it crashed in the second test flight.
• United States of America: During the duration of the conflict the United States captured many exemplars of Zeroes. Those captured during the war, some of them were repainted in US Navy colours and sent to mainland USA to be tested. The ones captured after or during the last stages of the war, were tested by the United States Army Air Force (USAAF), many of them at Clark Field, Philippines. 

Lastly, it seems that there were some reports of A6M2 and A6M5 Zeroes were used as interceptors after the war in 1946-1947 by both the Royal Thai Air Force and the Royal Thai Navy, however, the error seems to be erroneous, as more modern reports indicate that the Zero was never used by Thailand.

Also, it seems that pro-independence Indonesian Guerrillas captured some Zeroes and employed them against Dutch troops in the Indonesian War of Independence from 1945 to 1949. However, even if the reports seems plausible as the Indonesian employed many ex-Japanese aircraft in their National Revolution, we couldn't find any pic of an Indonesian Zero, so we decided not to draw a speculative profile.

Sources:

1. https://en.wikipedia.org/wiki/Mitsubishi_A6M_Zero

2. https://en.wikipedia.org/wiki/List_of_Mitsubishi_A6M_Zero_operators

3. https://captured-wings.wikia.org/wiki/ATAIU-SEA

4. https://web.archive.org/web/20161104191035/http://www.thai-aviation.net/files/Air_Force_Summary.pdf
5. http://www.worldairforces.com/countries/thailand/thl.html

6. https://en.wikipedia.org/wiki/Technical_Air_Intelligence_Unit

7. Signal Squadron - Aircraft In action 59 - Mitsubishi A6M Zero in Action

Messerschmitt Bf.108, part two

The Messerschmitt Bf.108 was widely used across the world. Some of the users were:

• Nationalist China: Apparently Nationalist China had at least one Bf.108B-2 in the ranks of their Air Force at the year 1939. Further information is required and the drawing should be considered as speculative.
• United Kingdom: The Royal Air Force (RAF) interned four Bf.108s at the outbreak of the war and put them into service under the designation of "Messerschmitt Adlon". They became the fastest communication aircraft of the RAF but they were often mistaken for Bf.109s, so they weren't employed very much. After the war, captured exemplars were used until at least 1948.
• Poland: The Polish Air Force used some captured Bf.108 after the war. They served until the very late 1940s.
• USSR: Before the war with Germany, the Soviet Air Force bought some few Bf.108s for evaluation. During the World War 2, many captured exemplars were put into service with the Soviet Air Force.
• United States: The U.S. Army Air Force (USAAF) evaluated some captured exemplars that were shipped to Freeman Army Airfield, in Indiana in September 1945. Apparently some of them served until the foundation of the U.S. Air Force (USAF) and flew for some time with the new American roundel in 1947.

Sources:

1. https://en.wikipedia.org/wiki/Messerschmitt_Bf_108

2. http://www.warbirdalley.com/bf108.htm

3. Wydawnictwo Militaria 149 - Messerschmitt Bf-108 Taifun

4. https://www.militaryfactory.com/aircraft/detail.asp?aircraft_id=347

Vultee P-66 Vanguard

During the late 1930s Vultee Aircraft Division conceived what later would be the Vultee Vanguard from a set of common wings ,aft fuselage and tail assemblies. Four designations were assigned by the company, V-48 for a single-seat fighter, BC-51 for a double-seat basic combat trainer, B-54 for an advanced combat trainer (where BC-54D would be the basic trainer variant). Eventually, the BC-51 became the Army Air Corps BC-3 and the BC-54D became the Vultee BT-13 Valiant.
Therefore, in 1938, Richard W. Palmer, designed the V-48 fighter. It featured a metal-covered, semi-monocoque fuselage and fully retractable landing gear. It was powered by a 1200hp Pratt & Whitney R-1830 radial engine. When the first prototype was being constructed, a decision was taken to lengthen the propeller shaft and install a tight cowling to provide a pointed nose to reduce drag. That way, the first prototype made its maiden flight in September 1939 piloted by Vance Breese. Nicknamed "Vanguard", on the 9th May 1940, when performing a test flight, the prototype collided with a Lockheed Sirius, while landing at Vultee airfield, severing one of the undercarriage legs. However, Breese managed to skillfully land the fighter with little additional damage. The prototype was subsequently rebuilt with the orthodox cowling that was employed in the subsequent exemplars.
Flight testing revealed inadequate cooling, however, measures to modify the cooling ducting were of little avail. The design was re-evaluated and it was reached to the conclusion that the insignificant drag reduce wasn't worth the added weight and ducting problems. The second prototype, named V-48X was modified with a conventional cowl, and the first aircraft was subsequently modified.
It flew for the first time on 11th February 1940 and, as result of flight tests, changes were made to the design including substantially increasing the areas of the horizontal and vertical tail surfaces.
On 6th February 1940 the Swedish government ordered 144 Vanguards which were labelled as the V-48C. The production prototype flew later on 6th September 1940. The model V-48C was similar to the V-48X except for the engine which was a later version of the R-1830 engine with a better high-altittude performance and provision for four 0.30in (7.92mm) machine guns in the wings and two 0.50in (12.7mm) machine guns in the fuselage.
When the aircraft was placed into production in September 1941, the U.S. Government placed an embargo on exporting the aircraft to Sweden. After the attack on Pearl Harbor and the subsequent reorganization of the U.S. Army Air Corps, they were given the designation of P-66. Production ended in April 1942 with around 50 aircraft were retained by the USAAF and used them mainly at pursuit training bases in the Western U.S. assigned to the 14th Pursuit Group in defensive roles. Pilots were impressed by the P-66s handling, however it was considered less than robust and a tendency to ground-loop destroyed more than 15 aircraft in landing accidents.
The British government took possesion of 100 P-66s which named them as Vanguard I with the intention of using them as advanced trainers in Canada. However, they reliquished the aircraft to China where 104 Vanguards, some of them being USAAC's machines, were shipped under lend-lease program. They were originally intended to serve with the 3rd American Volunteer Group (AVG), but plans for additional groups were discarded after the attack on Pearl Harbor.
In late 1942 the Chinese received the machines via India and they were pushed into service with USAAF insignia and serials as well as Chinese markings and Vultee serials on factory models.
It didn't have a distinguished career in China due to problems that began back in transit towards China when some were destroyed in tests in India and others were lost while en route to China. Most of the assembled P-66 were not marked as airworthy and were abandoned in Karachi, with just 12 Vanguards serving in Kunming with the 74th Fighter Squadron, 23th Fighter Group where they barely saw any action at all.
Two Chinese squadrons from the 3rd and 5th Groups, based at An-Su, saw some combat action with the Vanguard from August 1943 onwards. However, many P-66s were shot down on the ground during Japanese attacks and many others were shot down by friendly fire when they were mistaken for the Nakajima Ki-43 and Ki-44. Even if the P-66 had a decent top speed of 340mph (550Km/h), it wasn't a rival for the agile Japanese fighters in high-g maneouvers and they had to employ hit-and-run tactics against the Japanese.
In Chinese service, the P-66 was replaced by the Curtiss P-40 in 1943. Some few P-66s were placed in storage at caves for use in the upcoming civil war against the Chinese communists. However, as late as 1947 they were still in their crates and it's not known that they were using after World War II.

Sources:
1. https://en.wikipedia.org/wiki/Vultee_P-66_Vanguard
2. Salamander Books - The Complete Book of Fighters