The first night fighters in the Air Force were 60 surplus de Havilland Mosquitoes (J 30) delivered in  1948-49. They became based at Wing F 1 in Västerås, a former bomber wing. The Mosquito was a war product and the Swedish purchases were stricken by a lot of accidents. 23 aircraft, 38 % of the total, were lost beyond repair in crashes during five years, with the loss of life for 16 aircrew. The tolerance of the authorities had reached the end. Before the planned all-weather fighter J 32B could be taken in service, a safer substitute to the J 30 Mosquito had to be provided.

The Air Force had  good experiences of the J 28 de Havilland Vampire fighter. A contract of the delivery of the new design DH 112 NF.2 (Night Fighter Mk 2) Venom, a further development of the Vampire,  was signed with the British manufacturer. Fifty-nine aircraft were delivered and flown home to F 1 in Sweden 1952-53. 

The engines, de Havilland Ghost (RM 2A, 2.270 kp) and the armaments, 20 mm Hispano automatic cannons (4 per aircraft) were manufactured under license in Sweden and shipped to Britain.  Due to modified radar- and radio equipment compared with the RAF Venoms, de Havilland changed the designation NF.2 to NF.51. The Swedish designation became J 33.   

The J 33 had to be modified from the beginning. Problems when flying at high speeds had to be cured with modifications of the fuselage. Disturbances due to poor surface treatment had to be attended to. The Venom was not fitted with ejector seats and the cockpit canopy was  hard to open if it became necessary to bail out. A new, hydraulic opened canopy was designed. The radar equipment was also upgraded.  

The Swedish Venoms were replaced by J 32B Lansen during 1959-60. Four aircraft were kept as target-tugs, operated by Svensk Flygtjänst.  

The preserved J 33 on the photo is displayed at Flygvapenmuseum at Linköping. C/n 12374, Sw AF/n 33025.  

Updated 2010-02-13