Lebed-XII

32k b/w Lebed-XI at "History of aircraft construction in the USSR" by V.B.Shavrov, Vol.1 p.181;

T
wo-seat reconnaissance biplane, evolved from the German (110k) Albatros through the Lebed-XI as an intermediate variant. Despite its characteristics were far from remarkable, it played substantial role in Russian WWI airforce. The reason is that the only reliable engine of 150hp built in large numbers in Russia was 'Salmson'.
It was not a failure of aircraft designers that they had to rely on drag-inducing radial of 150hp while German aircraft were powered with in-line engines of 200hp and more. But it was Lebedev's failure that he did not provide the engine in proper cowling and fuselage modification to accommodate available engine in the best way he could.
Military Department was satisfied with quality of this aircraft, but its obsolescence became obvious in 1917.
Fuselage had rectangular cross-section, formed by four spars (30X30mm2 pine) and 3mm plywood skin. Such a construction was rigid, simple and reliable, despite heavier than one with bracing-struts and fabric cover. Wing had wooden spars and ribs, enforced by bracing wires. Tailplane was flat, wielded from steel tubes and covered with fabric.
First aircraft were tested with 130hp, later with 140hp Salmson. July 19, 1915 large batch of 225 aircraft were ordered, scheduled for following 2 years. Mass production started in August 1916 - year later! Until March 1, 1919 total 216 aircraft were build and 192 entered service, almost all with 150hp and only few with 140hp Salmson.
Aircraft was suitable for observation/reconnaissance. Having some advantages compared with 'Voisin' family, it was worser than 'Farman-XXX' and 'Anasal', what was revealed during comparison trials.
In practical operation 'Lebed-XII' did show all his nasty sides. It was not easy to fly, in some cases it did not get out of dive. Exhaust gases were send under the fuselage and often found their way to the cockpit, causing fatal fires in several occasions. It specially hard to excuse once the Lebed-XI already was built with exhaust stack going above the wing.
Despite all those troubles, aircraft was used in the Civil War and was on duty until 1924.
PredecessorDevelopment

Lebed-XI

Lebed-XIIbis
Other pieces of the story, from other sources:
Was used also as a bomber with pair under-wing hardpoints for 16kg ( Russian "pood") bombs and another pair for 20 pound bombs. Hardpoints were designed by Kolpakov and Miroshnichenko, tested February 7, 1917.
June 13, 1917 - was found unsuitable for front duties, retained as a trainer;
October 2, 1917 - completely rejected;
214 built.
Different pieces of this page do not fit together. How rejected aircraft could be built in such a substantial amounts? I'll try to find out and make it clear. Later.
References:
  • "History of aircraft construction in the USSR" by V.B.Shavrov, Vol.1 p.181-183;
    More Links...
  • Lebed XII
  • "Lebed XII" at Virtual Aircraft Museum
  • Technical data
    Type Lebed-XII
    Function Reconnaissance
    Year 1915 1916
    Crew 2 2
    Engines 1*140hp Salmson 1*150hp Salmson
    Length 7.9m 7.9m
    Wingspan 13.1m 13.1m
    Wing area 42.0m2 42.0m2
    Empty weight 840kg 862kg
    Loaded weight 1190kg 1212kg
    Wing load 28.4kg/m2 29.0kg/m2
    Power load 8.5kg/hp 8.1kg/hp
    Ground level Speed 125km/h 133km/h
    Ceiling 3000m 3500m
    Climb
    1000m 13.0min 8.5min
    3000m 67.0min 56min
    Armament
    Guns 1-2*mg
    Bombs 52kg
    Modified October 5, 1997
    by Alexandre Savine;
    Back to
    Main Gate