Nederlandse Modelbouw en Luchtvaartsite

History

The origin of this aircraft is not at the Curtiss Wright Company, but at the St. Louis Airplane Division, which was acquired early nineteenthirties by Curtiss.
A lightweight aircraft was designed, the CW-19L, a metal two-seater low wing monoplane with a radial engine. This model was intended as private aircraft.
Due to poor economic conditions, there was virtually no market for this aircraft.

In 1937 a military version was released, a trainer with the designation A-19R. This was equipped with a Wright R-975-E3 of 420 hp. 
A number of it were sold to Bolivia, China, Cuba and Ecuador. The light A-19R had a climbing speed of 10 m/s.
This was one of the reasons that in 1938 Curtiss started to develop a fighter version.
At that time there were quite different and, sometimes divergent, opinions on military aviation.
According to the Curtiss Technical Director George Page was a light weight fighter with a high rate of ascent the best defence against bombers.
Such fighters did not fight with other fighters, but would attack in a dive, than climb away quickly and then attack again in a dive and thus there was no need for no armour, etcetera.
The USAAF did have completely different ideas and showed no interest in this type of aircraft.

The new fighter, designated CW-21, was equipped with a Wright R-1820-G5 Cyclone radial engine of 1000 hp, two .50 machine guns and two .303 machine guns. The weight was just 1345 kg.
The result was a climb speed of 24.4 m/s. (4800 ft/min)
Contemporary, the Curtiss P-40 had a climb speed of less than 3000 ft/min and weighed more than twice as much.

The first flight followed on September 22, 1938. China was the first customer, Curtiss had a great interest in the Chinese Central Aircraft Manufacturing Company. In January 1939 the prototype arrived in Rangoon. After lots of discussion in China a contract was finally awarded for three aircraft and 27 sets of components. The prototype was also purchased.
The three CW-21s were shipped to China in May 1940.
After being assembled in Rangoon they were used for some time to protect the Camco plant against Japanese attacks.
Spring 1941, the aircraft were flown to Toungoon where the AVG (American Volunteer Group, with the famous Flying Tigers, were stationed. From there, the CW-21s would be flown to Kunming, the operational base. After a fuel stop in Lashio the aircraft flew on to Kumming. Because of the use of apparently bad fuel all three aircraft suffered severe engine problems and made an emergency landing in the mountains and all three aircraft were lost.

The production of the other aircraft had already started, but because of the rapid Japanese advance, the factory was evacuated to India. The CW-21's were probably lost when the factory was set to fire.

Meanwhile Curtiss claimed further improvements and developments of the CW-21, now for a trainer version, the landing gear was modified to collapse sideways in the wing instead of backwards in a kind of baking.
This trainer, designated CW-23 made the first flight in April 1939 in front of representatives of the U.S. Navy, U.S. Army Air Force and Canada, but no orders were placed, so the project was not pursued.
Further developments of the CW-21, the CW-21A with an Allison engine and the CW-21B, which had the modified undercarriage of the CW-23, but differed very little of the CW-21.
Due to the improved aerodynamics, the speed was higher and the flight range of 15% increased, however, because the weight had increased with more than 100 kg the climbing speed and the ceiling were lower than those of the CW-21.