A-90 Orlyonok

https://en.wikipedia.org/wiki/A-90_Orlyonok

The A-90 Orlyonok (Russian: ???????, English: "Eaglet") is a Soviet ekranoplan
(a ground effect vehicle) that was designed by Rostislav Evgenievich Alexeyev of
the Central Hydrofoil Design Bureau.

The A-90 uses ground effect to fly a few meters above the surface. The Russians
classify it as Ekranoplan Class B - it can achieve an altitude of 3,000 m (9,800
ft), placing between Class A - which is limited to ground effect, and Class C,
which exploits the ground effect only during take-offs and landings.

The Soviet Navy command of the 1960s was very interested in a fast military
transport capable of carrying a large payload. The Central Hydrofoil Design
Bureau was one of the organizations working on this top secret project, about
which little was known until the fall of the Soviet Union.

Chief Designer R.E. Alexeyev designed several prototypes in the 1960s. At the
start of the 1970s, Alexeyev designed a medium-sized Ekranoplan to be used as a
military transport. The new vehicle was named "Orlyonok" ("Eaglet"). The first
flying unit (S-23) was initially tested on the Volga River in the autumn of
1972, and the next year dismantled and transported to the Caspian Sea for
continued testing. In 1975 the S-23 crashed during testing, later proved to be
due to a deficiency in the alloy used for the hull. A different alloy was used
in all subsequent units built.


Role
Ekranoplan

Manufacturer
Central Hydrofoil Design Bureau

Designer
Rostislav Evgenievich Alexeyev

First flight
1972

Introduction
1979

Retired
1993

Primary user
Soviet Navy

Number built
5

The Orlyonok was designed as a transport and also as a beach assault vehicle.
Unlike other Soviet Ekranoplan designs, the Orlyonok was amphibious and was
equipped with wheels for beaching and land based takeoffs.

The layout of the engines on the Orlyonok was unusual and a testament of the
special needs of such an unconventional aircraft. Mounted in the top of the
tail, it featured a massive Kuznetsov NK-12 turboprop, the most powerful
turboprop ever made, which provided cruise power. The nose of the aircraft
mounted two turbofan engines with the intakes on top of the nose and the exhaust
along the side of the fuselage, the thrust of these engines being vectored under
the wings to produce PAR thrust (increased lift and extra propulsion) for
takeoff. Under cruise conditions and in ground effect, the front engines could
be shut off since their power was unnecessary to keep the aircraft aloft; this
also minimized intake of water, salt and low flying birds.

Both takeoff and landing were assisted with large span-length flaps that greatly
increased lift and could capture PAR thrust for increased air pressure. Water
landings were assisted with a hydro-ski that extended out of the belly of the
craft below the main wings.

The front end of the Orlyonok was hinged behind the radome and the whole
assembly could open sideways to speed disembarkation of the infantry it carried,
or of a BTR armoured personnel carrier. The Orlyonok had a built in folding ramp
that allowed it to load and unload vehicles with no external support.

There were plans to resume production of the Orlyonok. The craft would be built
in Petrozavodsk.

Overall only five units were built:

* Non-flying unit for static testing, scrapped
* S-23 flying unit, crashed in 1975
* S-21 rebuilt "S-23", completed in 1978, lost during an accident in 1992
* S-25 completed in 1979
* S-26 completed in 1980

The A-90 entered military service in 1979. Units S-21, S-25 and S-26 remained in
active service at least until 1993.

Specifications (A-90)

General characteristics
Crew: 6
Capacity: 150 personnel
Payload: 28,000 kg (61,730 lb)
Length: 58.1 m (190 ft 7 in)
Wingspan: 31.5 m (103 ft 4 in)
Height: 16.3 m (53 ft 5 in)
Wing area: 304 m² (3,272 ft²)
Max. takeoff weight: 140,000 kg (308,647 lb)
Powerplant: 2 × Kuznetsov NK-8-4K turbofan, 103 kN (23,155 lbf) each
1 × Kuznetsov NK-12MK turboprop, 11,033 kW (NK-12MV) (14,795 ehp)


Performance
Cruise speed: 400 km/h (248.5 mph)
Range: 1,500 km (932 mi)
Service ceiling: 3,000 m (9,842 ft)

Armament

Guns: 2 x 12.7 mm machine guns in twin dorsal turret




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