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.
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
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