Curtiss-Wright CW-21B Interceptor

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.

The Curtiss representative Walton visited the Netherlands in 1939 and this resulted in January 1940 in an order for 24 CW-21B's .
The delivery would take place between July and October 1940, so apparently Curtiss had already produced many components.
Even then there were some minor adjustments to be carried out to the aircraft; mounting the machine guns in the wings instead of in the nose and fuselage and these must be of the 7.9 mm calibre instead of the American .303 inch calibre. Also an extra 20 gallon fuel tank had to be added in the wing.
It proofed to be impossible to add both the wing tank and machine guns in the wing. The adjustment for only the installation of the machine guns in the wing would delay the delivery with at least two months.
So this requirement was dropped, but others were an additional armour plate for the pilot and a 16 gallon belly tank.
The Belgian FN would deliver 120 7.9 mm machine guns.

For the purchase, half April 1940 a pro-forma contract was signed for the delivery of 24 aircraft including the supply of six spare engines, six radios and 25% spare parts.
Before the final contract could be signed, the German invasion of the Netherlands took place and the subsequent capitulation was quite fast, so delivery to the Netherlands no longer necessary.

At the end of  May 1940, after consultation between the Minister of Defence and the Minister of Colonies (both in exile), it was decided to pass contract over to the NEIAF.
Curtiss-Wright strongly advised to replace two of the four .303 inch machine guns with two .50 inch machine guns, but this was rejected.
The final new contract was signed in mid-July 1940 and delivery would take place between August and October. The Wright Cyclone GR-1820-G5 engines had to be negotiated separately, but fortunately the delivery of these engines was no problem.

The first aircraft made its first flight in September 1940. In October, this aircraft and the second one underwent a large number of tests.
The empty weight of 1550 kg and the flying weight of 2042 kg, including the engine of almost 600 kg was mainly due to the omission of especially armour.

In February 1941 the first aircraft entered service. The CW-21s were assigned to two newly created divisions in the second section Fighters, later renamed to 2nd Division of Air Group IV (2-VlG.IV) and third division fighters, later renamed to 1st Division Airplane Group V (1-VLG-V), both stationed at Andir, Java.

During the armistice the armaments proved to be too light and the lack of armour appeared to be detrimental. The CW-21B could suffer very little battle damage.

On February 3, 1942 about 9 CW-21B's were already lost during Japanese attacks

Three Curtiss-Wright CW-21B Interceptors of the NEIAF.
[Enclosed photo from BeeldBank NIMH. Click on photo for ordering information]

Curtiss-Wright CW-21B Interceptor.
[Enclosed photo from BeeldBank NIMH. Click on photo for ordering information]

Curtiss-Wright CW-21B Interceptors.
[Enclosed photo from BeeldBank NIMH. Click on photo for ordering information]

Curtiss-Wright CW-21B Interceptor with crew.
[Enclosed photo from BeeldBank NIMH. Click on photo for ordering information]

1/72nd Scale

Kits

• MPM
  • Kit 72073: Curtiss CW-21B Demon
    • Building a model of the CW-21 by Rob de Bie
• Rareplanes
  • Kit 1007: Curtiss CW21 Demon

Modelling add-on

• --
  • Kit --: --.

Decals

• FlevoDecal
  • Set FD72-012 ML KNIL 1939-1942:A set decals containing decal for five different Brewster Buffaloes plus Curtiss Hawk 75, Curtiss CW-21B, Curtiss CW-22, Lockheed Lodestar, Ryan STM; Lockheed 12, Bücker Bu131; Messerschmitt Bf 108  and Martin WH-1 and WH-2.

1/48th Scale

Kits

• --
  • Kit --: --

Modelling add-on

• --
  • Kit --: --.

Decals

• FlevoDecal
  • Set FD48-012 ML KNIL 1939-1942:A set decals containing decal for five different Brewster Buffaloes plus Curtiss Hawk 75, Curtiss CW-21B, Curtiss CW-22, Lockheed Lodestar, Ryan STM; Lockheed 12, Bücker Bu131; Messerschmitt Bf 108  and Martin WH-1 and WH-2.

At the end of February 1942 the NEI Government ordered new national insignia to be used on the Dutch aircraft. From 28 February and on the Dutch flag had to be applied on al Dutch aircraft.
Due to the losses just about five CW-21Bs were left. It is uncertain whether these had the flag applied.

Camouflage scheme of the Curtiss CW-21B Interceptor of RNEIAF with orange triangles applied as national markings.

Camouflage scheme of the Curtiss CW-21B Interceptor of RNEIAF with flags applied as national markings.

Literature.

Websites.

• http://www.go2war2.nl/artikel/207
• Warbird Forum
• World War II: Curtiss CW-21
• Elevon: CW-21