A-90 Orlyonok

The A-90, known as “Orlyonok,” utilizes ground effect to maintain flight just a few meters above the surface. In the Russian classification, it falls under Ekranoplan Class B, with an operational altitude of 3,000 meters (9,800 feet), positioning it between Class A (limited to ground effect) and Class C (mainly relying on ground effect during takeoffs and landings while behaving like a standard aeroplane in between).

During the 1960s, the Soviet Navy was keenly interested in a high-speed military transport capable of carrying substantial cargo. The Central Hydrofoil Design Bureau was among the organizations involved in this secretive project, the details of which remained hidden mainly until the Soviet Union’s dissolution.

Chief Designer R. E. Alexeyev developed multiple prototypes in the 1960s. In the early 1970s, Alexeyev created a medium-sized ekranoplan for military transport called “Orlyonok” or “Eaglet.” The first flying unit (S-21) underwent initial testing on the Volga River in the autumn of 1972 and was subsequently transported to the Caspian Sea for continued testing the following year. Unfortunately, in 1975, the S-21 crashed during testing, attributed to a deficiency in the alloy used for the hull. Subsequent units incorporated a different alloy.

DESIGN & DEVELOPMENT

In terms of design and development, the Orlyonok was conceived as a transport and a beach assault vehicle, distinguishing it from other Soviet Ekranoplan designs. Notably, it was amphibious and equipped with wheels for beaching and land-based takeoffs.

The unique engine layout of the Orlyonok accommodated its unconventional nature. It featured a massive Kuznetsov NK-12 turboprop engine mounted on top of the tail, providing cruise power. Additionally, the nose of the aircraft housed two turbofan engines with unique intakes and exhaust configurations. Combined with underwing thrust vectoring, these engines generated PAR thrust for takeoff. During cruise and ground effect flight, the front engines could be deactivated to reduce water intake and enhance efficiency.

The Orlyonok utilized large span-length flaps to facilitate takeoff and landing, enhancing lift and harnessing PAR thrust. For water landings, a hydro-ski extended from the belly of the craft beneath the main wings. The Orlyonok also featured a hinged front end that could open sideways to expedite the disembarkation of troops or vehicles, such as a BTR armoured personnel carrier. A built-in folding ramp allowed for vehicle loading and unloading without external assistance.

PRODUCTION HISTORY

Although there were plans to resume Orlyonok production in Petrozavodsk, only four units were ever constructed:

• One non-flying unit for static testing was eventually scrapped.
• S-21, completed in 1972, sustained damage in 1975, was rebuilt as S-23 in 1977, and later lost in 1992.
• S-25, completed in 1979, was retired in 1993 and scrapped around 2000.
• S-26, completed in 1980, was retired in 1993 and is currently on display at the Museum of the Navy in Moscow.

The A-90’s specifications are as follows:

• Crew: 6
• Capacity: 150 personnel or 28,000 kg (61,729 lb).
• Length: 58.1 m (190 ft 7 in).
• Wingspan: 31.5 m (103 ft 4 in).
• Height: 16.3 m (53 ft 6 in).
• Wing area: 304 m² (3,270 sq ft).
• Max takeoff weight: 140,000 kg (308,647 lb).
• Powerplant: 1 × Kuznetsov NK-12MK turboprop engine, 11,033 kW, mounted at the fin/tailplane junction.
• Powerplant: 2 × Kuznetsov NK-8–4K turbofan engines, each generating 103 kN (23,000 lbs) thrust, mounted in the nose.
• Propellers: 8-bladed contra-rotating constant-speed propeller.

In terms of performance:

• Maximum speed: 400 km/h (250 mph, 220 kn).
• Range: 1,500 km (930 mi, 810 nmi).
• Service ceiling: 3,000 m (9,800 ft).

Additionally, the A-90 is armed with 2 x 12.7 mm machine guns in twin dorsal turrets and can fly over land using ground effect, although this is riskier. It can also generate enough lift using standard aerodynamic principles to reach higher altitudes. As a military vehicle, the A-90 has large wheels, enabling it to rapidly offload cargo on land after landing in shallow waters. The entire cockpit and nose can tilt upward to reveal a spacious, windowless cargo area capable of transporting a whole armoured vehicle and a full company of troops. The A-90 boasts an impressive cargo capacity of 61,000 pounds, making it a highly efficient seaplane.