Military Wiki
Artist's illustration of the KM
Role Ekranoplan
Manufacturer Central Hydrofoil Design Bureau
Designer Rostislav Evgenievich Alexeev
First flight October 16, 1966
Status sunk in 1980
Number built 1

The Caspian Sea Monster, officially «KM» (Korabl Maket, Russian - Корабль-макет Naval Prototype),[1] also known as the "Kaspian Monster", was an experimental ekranoplan, developed at the design bureau of Rostislav Alexeyev.


The KM was designed in 1964—1965. It was a unique by size and payload. The first spy photographs from American spy satellites showed a strange aircraft carrying letters "KM" on its fuselage. CIA disambiguated it as "Kaspian Monster", while it actually meant "Korabl maket" - "prototype ship" in Russian. Chief designer for this aircraft was Rostislav Alexeyev, lead engineer — V.Efimov.[2][3][4][5]

The ekranoplan had wingspan of 37.6 m, length - 92 m, maximum take-off weight - 544 tons. Until An-225 it was the largest aircraft in the world.

KM was designed as a special vehicle for the military and rescue teams. However designing such a machine caused serious difficulties. It was documented as a marine vessel and prior to the first flight a bottle of champagne was broken against its nose. It displayed the Soviet Navy Flag and was assigned to the Soviet Navy, since the ground effect is only possible within several meters from the surface. The new vehicle was, however, piloted by air force test pilots.


KM testing started in 1966 at the Caspian sea near Kaspiysk (Dagestan).

First flight was performed by V. Loginov and Rostislav Alexeyev himself, which was very unusual - most Soviet aircraft designers never piloted their own creations. All works were conducted under patronage of the Ministry of shipbuilding industry.

KM was tested at the Caspian Sea for 15 years until 1980. In 1980, pilot error caused a crash without human casualties. The vehicle was too heavy to be recovered from its watery wrecksite.[6]

Specification (KM)

Data from The Osprey Encyclopedia of Russian Aircraft 1875 - 1995,[7] Russias Ekranoplans:The Caspian Sea Monster and other WiG Craft[8]

General characteristics

  • Length: 92.00 m (301 ft 10 in)
  • Wingspan: 37.60 m (123 ft 4 in)
  • Tail stabilizer span: 37 m (121 ft 5 in)
  • Height: 21.80 m (71 ft 6 in)
  • Wing area: 662.50 m2 (7,131.1 sq ft)
  • Empty weight: 240,000 kg (529,109 lb)
  • Max takeoff weight: 544,000 kg (1,199,315 lb)
  • Powerplant: 10 × Dobrynin VD-7 turbojet, 127.53 kN (28,670 lbf) thrust each


  • Maximum speed: 500 km/h (311 mph; 270 kn)
  • Cruising speed: 430 km/h (267 mph; 232 kn)
  • Range: 1,500 km (932 mi; 810 nmi)
  • Ground effect altitude: 4–14 m (13 ft 1 in–45 ft 11 in)
  • Maximum sea state: 1.2 m (3 ft 11 in)

See also

In media

  • Microsoft Flight Simulator X features KM in some missions.


  1. Liang Yun, Alan Bliault, Johnny Doo; WIG Craft and Ekranoplan: Ground Effect Craft Technology; Page 42 (2009)

    "In Russian KM stands for “Naval Ship Prototype”, not “Caspian Sea Monster” [4]. The craft was 92.3 m overall length, 37.6 m maximum width, 22 m maximum height and weighed 544 t, almost twice that of the Boeing 747 jet airliner models ...

  2. Sergey Komissarov; Russia's Ekranoplans: The Caspian Sea Monster and Other WIG Craft; (2003)

    "As such they promptly attracted the attention of the military and thus have been veiled in secrecy until recently .The book describes in detail the many series of WIGE vehicles developed by various design bureaus, including the Orlyonok, the ..."

  3. National Research Council; Reducing the Logistics Burden for the Army After Next Committee to Perform a Technology Assessment Focused on Logistics Support Requirements for Future Army Combat Systems; Page 68 (1999)

    "The Russians have developed this technology to the point of demonstrating large WIG aircraft, notably the Caspian Sea Monster, which has a maximum takeoff weight of 540 metric tons. This large aircraft has flown at 650 km/h (350 knots) just ..."

  4. Liang Yun, Alan Bliault; High Performance Marine Vessels; Page 89 (2012)

    "NATO called this flying object the “Caspian Sea Monster”. Analysis suggested the craft was actually double the size of a Boeing 747, weighing about 500 t, so that it could possibly accommodate about 900 marine troops (Fig. 3.1)."

  5. Anne H. Cahn; Killing Detente: The Right Attacks the CIA; Page 65 (1998)

    "It depicted "the Great Caspian Sea Monster," purporting to be the largest aircraft in the world, weighing five hundred tons. Like the hovercraft, the ship was to ride on an air cushion at speeds up to 350 miles per hour. Flying only twenty-five to ..."

  6. The Register; In search of the Caspian Sea Monster; Lester Haines; 22 September 2006
  7. Gunston, Bill (1995). The Osprey Encyclopedia of Russian Aircraft 1875-1995. London: Osprey Aerospace. pp. 512–513. ISBN 1855324059. 
  8. Komissarov, Sergey (2002). Russias Ekranoplans:The Caspian Sea Monster and other WiG Craft. Hinkley: Midland Publishing. ISBN 1857801466. 

External links

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