At the end of the 1940s, Vladimir Dobrynin's engine
design bureau had developed a new air-cooled, twenty-four-
cylinder in-line piston engine, the VD-4K, which
offered a 4,300hp supercharged power output.
Dmitri Markov set about designing a very long-range
strategic bomber with these engines. Starting
from the Tu-80 he began by designing a high-aspect
wing with increased span - now it was 55.94m compared to the 43.83m of the Tu-75
and Tu-80, and wing area was 273.6m2, compared to 162.7m2. Wing aspect
ratio was 11.4:1. This allowed the new aircraft to carry
some forty-four tonnes of fuel which would give it a
range of 12,000km. He streamlined the
fuselage, and provided accommodation for a second
crew which would be needed with the aircraft's twenty-six-
hour endurance capability. Normal crew was eight
so the Tu-85 carried sixteen in a pressurised cabin. The
Tu-85 was fitted with large four-blade propellers, and
it was armed with five turrets each fitted with a pair of
NR-23 cannons which could be remotely controlled by
a gunner, who had a screen to show the arc of fire from
each position a development of the B-29/Tu-4
system.
The Tu-85 was constructed at factory N 156 in 1949
and 1950. When completed, it was brought to
Zhukovski aerodrome, reassembled and readied for
flight. On 9 January 1951, Aleksei Pereliot was in
command as it took off for the first time. In factory
and state tests, it gave excellent results. Although its
empty weight was 55.4 tonnes and its normal take-off
weight seventy-five tonnes, it could take off at 107
tonnes when necessary, allowing it to carry the enormous
fuel load needed to achieve its 12,300km
range with a five-tonne payload, or to increase its
normal five-tonne bomb load to twenty tonnes.
Cruising speed for maximum range was established at
450km/h, but maximum speed was
much higher. At low level, it was measured at 563km/h, and at a level of 10,000m it
reached 665km/h.
But by now, turbine engines were establishing themselves
and offering higher speeds with lower fuel burns.
The Tu-85 was the end of the line for Tupolev's piston-engined,
and also for Soviet, aircraft. Although the
United States would stay with pistons for another five
years, for the Soviet Union, and for Europe, the time
had come to move on.
Only one Tu-85, the prototype was built. It was the
last large Tupolev aircraft without swept wings.
