Via my dear Sarastro and Letectvi,Pre-1945,
Av.37 was a three seat low-wing reconniassance and photographic monoplane
project,based on Av.36,also powered by two engines
Av.41 was a two-seat fighter biplane project,based on B-34,powered by one
500 hp Avia 12 Ycrs engines,two fixed machine guns and a twin machine gun
for the second crew member
Av.55 was a tanden two-seat high-wing sporting and light monoplane project
of 1930,had a fuselage made of steel tubes, wooden wings with simple V-struts, powered by one 40 or 50 hp Koželuh DFTr engine,span 10m,length 5.85m,height 1.7m, load capacity 14 m". empty weight 220 kg, in flight 420 kg. surface load 30 kg/m". max. speed 135 km/h. cruise 100 km/h. landing 40 km/h, range 300 km,
reach 3500 m. climb rate 180/min