A-90 Orlyonok

Central Hydrofoil Design Bureau
Industry	Aerospace engineering
Founder	Rostislav Evgenievich Alexeyev
Headquarters	Soviet Union

The A-90 Orlyonok () represents a Soviet innovation conceived by Rostislav Evgenievich Alexeyev at the Central Hydrofoil Design Bureau.

Utilizing the ground effect, the A-90 glides mere meters above water surfaces. Russia categorizes it as an Ekranoplan Class B, capable of reaching altitudes up to , situating it between Class A (restricted to ground effect flight) and Class C (which employs ground effect only during takeoff and landing phases).

History

During the 1960s, the Soviet Navy required a rapid military transport with substantial cargo capacity. Under Chief Designer R. E. Alexeyev, the Central Hydrofoil Design Bureau initiated this classified project. Initial prototypes appeared in the 1960s, culminating in the medium-sized ekranoplan dubbed Orlyonok ('Eaglet') in the early 1970s. The first operational model (S-21) underwent trials on the Volga River in 1972 before relocating to the Caspian Sea. Following a 1975 accident caused by a flaw in the hull alloy, later versions incorporated enhanced materials.

Development and design

Conceived as both a transport and amphibious assault craft, the Orlyonok was equipped with wheels allowing it to operate from beaches and perform land-based takeoffs, distinguishing it from other Soviet ekranoplans.

Its design evolved from the SM-6 prototype, which shared a modular configuration. Insights gained from the SM-6 influenced the Orlyonok development. The SM-6 was exhibited at Kaspiysk naval base before being dismantled between 2006 and 2008.

The Orlyonok featured a distinctive engine arrangement tailored for its operational demands: a robust Kuznetsov NK-12 turboprop mounted atop the tail supplied cruise propulsion, while two turbofan engines positioned at the front generated vectored thrust beneath the wings during takeoff (PAR thrust). These forward engines could be deactivated during cruising to minimize water and debris ingestion.

Extended span flaps increased lift during takeoff and landing by harnessing PAR thrust to boost air pressure. For water landings, a retractable hydro-ski extended beneath the main wings.

The forward fuselage section behind the radome was hinged to open sideways, facilitating swift deployment of infantry or BTR armored personnel carriers through an integrated folding ramp, enabling vehicle loading without external assistance.

There were intentions to restart Orlyonok production at Petrozavodsk.

Production

A total of four units were constructed:

One non-operational model for static tests, subsequently scrapped.
S-21 completed in 1972; after damage in 1975, rebuilt as S-23 in 1977; lost in 1992 and dismantled due to prohibitive salvage expenses borne by the Russian Navy.
S-25 finalized in 1979; decommissioned in 1993 and scrapped around 2000.
S-26 completed in 1980; retired in 1993 and currently exhibited at Moscow’s Museum of the Navy.

Operators

External links

References