Kingdom of Hungary (1938)
Reconnaissance Aircraft & Light Bomber – 128 Built

The Hungarian Aviation industry was rather small in scope in comparison to many in Europe. Regardless, it managed to introduce a number of domestic development projects. One of these was the Weiss Manfréd from WM 21, a two-seat reconnaissance aircraft of which some 128 were produced during the Second World War.

History

In the years after the First World War, Hungary was strictly forbidden from developing combat aircraft. To overcome this limitation, the Hungarians did what the Germans did and began developing a civil aircraft industry to help gain valuable experience in aircraft design. One of these companies that would emerge during the late 1920s was Weiss Manfréd, from Csepel near Budapest. In 1928 this company began working on the design and construction of gliders and engines.

Due to an initial lack of funds, the Hungarian Air Force was forced to rely on foreign aircraft that were bought in relatively small numbers. For example, by 1937 Hungarians had only around 255 operational aircraft. To help gain more experience, Weiss Manfrédfrom began producing Fokker F.VIII and C.V aircraft under license. When sufficient funds and experience were gained, Weiss Manfrédfrom engineers in 1935 began working on a new reconnaissance biplane design.  They decided on a simple design, reusing some components that were already in production, and it would be a further development of the already produced WM 16 model, which was heavily based on the D version of the Fokker C.V.

When the prototype of the new short-range reconnaissance aircraft, WM 21 “Sólyom” (Falcon) was completed, it was presented to Hungarian Air Force officials, who were generally satisfied with its performance and gave an order for some 36 WM 21 in 1938. At that time, massive funds were being allocated to the development of the aircraft industry. In addition, Hungarian Air Force officials wanted to decentralize aircraft production. For this reason, the WM 21 was to be built by various other companies, including twelve to be built by MÁVAG  and MWG

It was estimated that the production would commence during April and March 1939. It took longer to do so, with the first aircraft being available at the end of 1939. While the aircraft was slowly put into production, the Hungarian Air Force asked for more aircraft to be built.

In Combat

The WM 21 was primarily designed as a reconnaissance aircraft but due to a general lack of other aircraft types, it would be adopted for other roles. Its first combat use was during the so-called Transylvanian Crisis. Namely, in June 1940 Hungarian government demanded that Romania return the Transylvania region to them. Since it looked like war was coming, Hungarian Air Force began relocating its aircraft close to the Romanian border. Thanks to the commencement of negotiations, no war broke out. But by late August the Hungarians ordered a complete mobilization as the negotiation led nowhere.

Germany did not want to lose its vital Romanian oil supply and forced both countries to begin new negotiations under German and Italian supervision. While the negotiations were underway, some smaller air skirmishes occurred. On the 27th of August, a Romanian He 112 attacked a Hungarian Ca 135 aircraft, which was heavily damaged and one crew member was killed. The following day a WM-21 piloted by Captain János Gyenesin, dropped bombs on the Romain Szatmárnémeti airfield in retaliation for the lost airman. On its way back it crash-landed, damaging the aircraft. In the end, Hungary emerged as the victor, gaining large territorial concessions over the Romanians.

When the April War broke out on the 6th of April 1941, between the Kingdom of Yugoslavia and the Axis, the Hungarians joined the offensive. They employed their 1st Air Brigade which had some 60 aircraft. By the 17th of April, the war was over, and the Hungarian Air Force had lost 6 aircraft including one WM 21.

On the 26th of June 1941, the Hungarian town of Kassa was bombed by three aircraft. The circumstance of this incident is not clear even to this day, but the Hungarian government asserted that it was a Soviet attack. The decision was made to declare war on the Soviet Union as a response.  For the initial operation in the war against the Soviets, the Hungarian Air Force allocated 25 bombers (Ju 86 and Ca 135), 18 CR 42 fighters, and the 8th and 10th reconnaissance squadrons each equipped with 9 WM 21.

By 1942 most WM 21’s were allocated for use by training schools and as liaisons. Some would be used in later years for anti-partisan operations. By the end of the war, some WM 21 pilots managed to reach Austria where they hoped to surrender to the Western Allies.

Technical Characteristics 

The WM 21 was a mixed-construction, biplane aircraft, designed to fulfill multiple roles. The fuselage and the wings were of metal construction which was covered in fabric. The lower and the upper wings were connected with each other by one “N” shaped metal strut on each side. In addition, there were two “V” shaped metal brackets that were connected with the fuselage and the upper wing.  Lastly, there were two larger metal struts on each side that connected the landing gears to the top wing.

The landing gear consisted of two fixed road wheels and a rear-positioned landing skid. Partly-covered front wheels were connected to the aircraft fuselage by three large metal bins.

Initially, the WM 21 was powered by an 870 hp Weiss WM K-14A radial piston engine. With this engine, the WM 21 could reach a maximum speed of 320 km/h. Later produced aircraft were equipped with a stronger 1,000 hp WM K-14B engine. With this engine, the maximum speed was increased to 380 km/h.

The pilot and the observer/machine gunner were placed in two separate open cockpits, the front for the pilot, and the rear for the observer.  For better downward visibility the observer was provided with two fairly large glass panels, placed just under him on both fuselage sides.

The WM 21 was armed with two forward-firing 7.92 mm Gebauer machine guns. One additional defensive machine gun was placed in a flexible mount which was installed in the rear cockpit. Additionally, the offensive capabilities of the aircraft could be increased by adding bombs. The bomb bay was placed between the two crew members. To release the bomb the crews would use a release mechanism. The bomb load could consist either of 12 10kg anti-personnel bombs, or 60 1kg incendiary bombs. Later versions increased the bomb load to around 300 kg.

Production and Modifications

The WM 21 was produced in four small series. When the production ended in 1942 some 128 aircraft would be constructed. While designed by Manfred Weiss, this factory produced only 25 aircraft. The MAVAG produced 43 with the 60 being built by MWG. Due to the relatively low production numbers, only one modification of the original aircraft was ever made:

•  WM 21A – Powered with an 870 hp Weiss WM K-14A engine,
• WM 21B – Slightly improved version powered by 1.000 hp  WM K-14B engine

Conclusion

The WM 21 was a Hungarian reconnaissance aircraft that would see service on several different fronts. While initially used in its intended role, it quickly became obsolete and was allocated to secondary missions, as a training aircraft or for liaison missions. Due to a lack of adequate aircraft, some WM 21would even see service as combat aircraft against Partisans forces, mostly in the Soviet Union.

WM-21A Specifications
Wingspan	12.9 m / 42 ft 4 in
Length	9.65 m / 31 ft 8 in
Height	3.5 m / 11 ft 5 in
Wing Area	32.75 m² / 352.53 ft²
Engine	One 870 hp (649 kW) Weiss WM K-14A radial piston engine
Empty Weight	2,450 kg / 5,400 lb
Maximum Takeoff Weight	7,606 kg / 3,450 lb
Maximum Speed	320 km/h / 200 mph
Cruising Speed	275 km/h / 170 mph
Range	750 km / 466 mi
Maximum Service Ceiling	8,000m / 26,245 ft
Climb speed	Climb to 6,000 m (19,700 ft) in 7 minutes and 30 seconds
Crew	One pilot
Armament	Three 7.92mm machine guns Total bomb load of some 100-300kg

Gallery

Credits

• Written by: Marko P.
• Edited by:
• Illustrations by Carpaticus

Sources:

• D. Monday (1984, 2006) The Hamlyn Concise Guide To Axis Aircraft Of World War II, Aerospace Publishing Ltd.
• G. Sarhidai, G. Punka, and V. Kozlik (1996) Hungarian Eagles, Hikoki Publication
• G. Punka (1994) Hungarian Air Force, Squadron Publication
• S. Renner. (2016) Broken Wings The Hungarian Air Force, 1918-45, Indiana University Press
• http://all-aero.com/index.php/56-planes-v-w/15565-weiss-wm-21-solyom