The SM-8 [ekranoplans, or wing-in-ground-effect (WIG) craft] WIG vehicle built in 1967 became the second 1/4th scale analogue of the KM ekranoplan; it reflected the changes introduced into the layout of the KM in the course of its design. The SM-8 became the last in the family of SM experimental flying vehicles, the tests of which furnished results essential for the creation of theory and for evolving the methods of designing and developing new models of heavy WIG vehicles for military and civil applications. The testing of the SM-8 proceeded in parallel with the testing of the KM; the analogue served for checking the methods of testing its bigger stablemate.
The SM-8, having an all-up weight of 8,100 kg (17,860 lb), was powered by one turbojet located in the upper part of the fuselage ahead of the fin. Its air intake was protected from spray by a special U-shaped guard. To emulate the blowing (booster) engines of the KM, the SM-8 was provided with a special nozzle device in the front fuselage intended to direct part of the gases bled from the engine under the wings. The vehicle had a cruising speed of 220 km/h (137 mph).
The construction and testing of the SM series (SM-1 through SM-8) were directly connected with the creation of designs that marked the apex of the Central Hydrofoil Design Bureau’s achievements – the vehicles known as KM, Loon’ and Orlyonok.
In 1963, in response to an order placed by the Navy, construction was started at the ‘Volga’ shipyard near Gor’kiy (now Nizhny Novgorod) of a gigantic WIG vehicle which was designated KM (korahbl’-maket – ‘mock-up ship’, or rather prototype ship). It was a machine of staggering dimensions, the length of the hull exceeding 90 m (295 tt). It was launched in March 1966 and the first flight took place on 18th October of that year. Further testing of the WIG vehicle took place on the Caspian Sea. Its optimum flight altitude in ground effect proved to be 4 to 14 m (13 to 46 tt). At that time the KM (sometimes referred to as KM-1 in Western sources) was the biggest flying vehicle in the world – its weight in one of the flights reached 544 tonnes (1,299,300 Ib)! Small wonder that it was nicknamed ‘Caspian Sea Monster’ in the West (later some Russian journalists, too, deciphered KM as Kaspeeyskiy monstr). This huge machine was powered by 10 Dobrynin VD-7 turbojets with a thrust of 13,000 kgp apiece; of these, two engines located at the fin leading edge served as cruise engines, while the remaining eight engines were mounted in two packages of four on the forward fuselage sides, performing the role of booster engines for power-augmented takeoff. The machine reached a maximum speed of 500 km/h (310 mph), the cruising speed being 430 km/h (267 mph).
The KM had good manoeuvrability, stability and controllability; it could perform tight turns with large bank angles, the wingtip float touching the sea surface. This machine flew for 15 years and earned a reputation for being a very reliable means of transport. Unfortunately, in 1980 the KM crashed due to pilot error. The pilot, who had not been at the controls of the big machine for a long time, overdid the pitching-up at take-off. The machine began to rise steeply. Losing his head, the pilot throttled back abruptly and applied the elevator in a fashion contrary to flight manual. The winged ship started banking to port, impacted the water surface and sank; the crew escaped unhurt.
In the course of its testing the KM underwent a number of modifications some of which were rather substantial. For example, in 1979 the cruise engines placed on the fin were transferred to a pylon mounted over the forward fuselage so as to lessen spray ingestion. The cruise engines were provided with spray deflectors on the intakes.
Orlyonok (Project 904)
A Soviet BTR-60PB eight-wheel armoured personnel carrier is about to roll off the Orlyonok. This view shows the design of the double-hinged loading ramps, the overhead actuating cylinder and the many securing clamps around the hatch perimeter; the latter is natural, considering the high stresses in the area.
This troop-carrier/assault WIG vehicle designed in response to an order from the Navy made its first flight from one of the channels of the Volga river in 1972. After this, disguised as a Tupolev Tu-134 airliner, the prototype was transported on a barge to Kaspiysk (a naval base on the Caspian Sea) to be tested in sea conditions. It was the first WIG vehicle intended for speedy transportation of troops and materiel. Its cargo hold measuring 21 m (68 ft 11 in) in length, 3.2 m (10ft 6 in) in height and 3.0 m (9 ft 10 in) in width made it possible to transport self-propelled vehicles that were on the strength of the Soviet Marines.
The Orlyonok features an aircraft layout. It is an all-metal cantilever monoplane with a fuselage provided with hydrodynamic elements in its lower portion (planing steps, hydroskis etc.); it has low-set wings and a T-tail with a horizontal tail of considerable dimensions. Its powerplant comprises two Kuznetsov NK-8-4K booster turbofans rated at 10,500 kgp (23,148 Ib st) for take-off (provision was made for their eventual replacement with 13,000-kgp/28,660-lb st NK-87 turbofans) and one 15,000-ehp NK-12MK cruise turboprop (a version of the NK-12M used on the Tu-95 bomber) driving AV-90 eight-blade contra-rotating propellers. All the engines are maritime versions of the respective aircraft engines. The booster engines are fitted with special pivoting nozzles and used not only for creating an air cushion on take-off by directing their efflux under the wings (blowing mode) but also for acceleration to cruising speed. The air intakes of the NK-8-4K engines are blended into the contours of the forward fuselage, which reduces drag and helps protect the engines from corrosive sea spray. The cruise engine is located at the junction of the fin and horizontal tail; being placed so high, it is less vulnerable to spray ingestion at take-off and landing and to salt contamination from aerosols whose density depends on the height over the sea surface.
The fuselage of the Orlyonok is of beam-and-stringer construction; it is divided into three sections – forward, centre and aft. The centre fuselage accommodates the cargo hold accessed by swinging the hinged forward fuselage 92° to starboard. The hinged part of the fuselage houses the flight deck, the booster engines and a radar in a ‘thimble’ radome. The aft fuselage houses a compartment for auxiliary power units and accessories required for starting the main engines and operating the vehicle’s electrical and hydraulic systems. Placed dorsally on the hull are a turret with twin cannons, the antenna of a navigation radar, direction finder aerials, communication and navigation equipment aerials. To reduce shock loads in the take-off and landing mode the designers introduced hydroskis shaped as simple deflectable panels. The craft is equipped with a wheeled undercarriage intended for beaching the machine and rolling it along paved taxiways on the shore.
The low-set wings of trapezoidal planform comprising an integral centre section and outer wing panels of torsion-box construction are fitted with flaperons. The lower surface of the wings along the leading edge, closer to the wing tips, incorporates special hinged panels which are deflected 70° during takeoff. The wingtips carry floats doubling as endplates. The wing high-lift devices are used for creating an air cushion which lifts the vehicle out of the water. During take-off the efflux of the jet engines is directed under the wings; the pilot lowers the flaps and leading-edge panels, thus barring the way for the gas tending to escape fore and aft. The increased gas pressure under the wings lifts the machine out of the water. The main part of the wings, with the exception of the flaps and leading-edge panels, is manufactured watertight. The wing is divided into 14 watertight bays, two of which are used for fuel.
The sharply swept T-tail comprises a fin/rudder assembly and large-span stabilisers with elevators.
Here are some basic characteristics and performance figures: the machine measures 58.1 m (190 ft 7 in) in length and 31.5 m (103 ft 4 in) in wing span, the width and height of the hull being 3.8 m (12 ft 6 in) and 5.2 m (17 ft) respectively; it has an all-up weight of 125,000 kg (275,600 Ib) and an empty weight of 100,000 kg (220,500 Ib). The Orlyonok’s maximum speed is 400 km/h (249 mph), the cruising speed being 360 km/h (224 mph). The height of flight over the supporting surface can vary from 0.5 m to 5 m (1 ft 8 in to 16 ft), the optimum height being 2 m (6 ft).
To relieve the crew workload in flight, provision is made for automatic stabilisation of the altitude (by deflecting the flaps), the pitch angle (by deflecting the elevators), the heading (by deflecting the rudder) and the bank angle (by deflecting the ailerons). In addition to the first prototype which crashed in 1975, an initial batch of three Orlyonoks was manufactured; they were adopted for squadron service by the Navy and underwent evaluation from 1979 onwards. Each of the three examples had its own factory designation; these three Project 904 machines were designated 8-21, 8-25 and 8-26 (as can be seen on photos, the machines were serialled 21 White, 25 White and 26 White for the greater part of their service career). In the Navy they were known as the MDE-150, MDE-155 and MDE-160 respectively (MDE presumably means morskoy desahnfnyy ekranoplahn – seagoing transport and assault WIG vehicle). They were taken on charge by the Navy on 3rd November 1979, 27th October 1981 and 30th December 1981 respectively. The Naval Command presumed that the WIG vehicles would demonstrate high effectiveness (considerable speed and ensuing capability for surprise actions, capability for overcoming anti-assault obstacles and minefields) and would ensure the seizure of bridgeheads at a coastline defended by the enemy. There were plans in hand for manufacturing 11 Orlyonok (Project 904) machines during the 12th and 13th five-year plan periods (1981-1990), to be followed by the construction of transport and assault WIG craft of a new type (with a new project number) possessing greater cargo carrying capacity. Preparations were made for establishing a WIG vehicle-operating unit in the Red Banner Baltic Fleet. However, for several reasons these plans did not come to fruition. The Orlyonok WIG craft were doomed never to leave the Caspian Sea.
Initially they were operated by the specially established 236th Squadron of WIG vehicles within the brigade of transport and assault ships of the Red Banner Caspian Flotilla. Later an idea cropped up of transferring the WIG vehicles under the authority of headquarters of the Naval Aviation, but these plans met with much opposition on the part of the latter. An end to these disputes was formally put by Order No. 0256 issued by the Minister of Defence on 12th November 1986 under the terms of which ekranoplans became part of the aviation element of the Navy’s Fleets. The document prescribed that WIG vehicles, as well as aircraft and helicopters, must be regarded as a class of the Naval Aviation’s weaponry. In accordance with directive No. DF-035 dated 21st April 1987 the WIG craft operating unit, renamed 11th Air Group, was formally placed under the command of the Black Sea Fleet, albeit it retained its former base on the Caspian Sea the town of Kaspiysk.
The incorporation of the WIG vehicles into the normal activities of the armed forces was not trouble-free and was not pursued all too vigorously. Much time was spent on repairs and modernisation (albeit the machines were almost brand-new!). There were difficulties with crew training. By 1983 four crew captains had received sufficient training; all of them had previously flown the Beriyev Be-12 Chaika ASW amphibian. Up to 1984 crew training was undertaken in accordance with the ‘Temporary course for training the crews of ekranaplan ships’ prepared by the combat training section of the Navy. Later the manual was reworked with participation of the combat training section of the Naval Aviation.
In 1983 GNII-8 VVS (State Research Institute NO. 8 of the Air Force) joined in the test-pulled up a second time and impacted again, sustaining severe damage. Of the ten crew on board nine persons survived, albeit with injuries, and were eventually rescued. The tenth crew member – a flight engineer – was killed. The crippled Orlyonok drifted 110 km (60 nm) and was eventually blown up – the Russian Navy could not afford the price asked for its retrieval by salvage companies. It was presumed that the crash had been caused by a failure of the automatic stability system, although pilot error is also cited.
After this the remaining WIG complement of the Navy came to include two Project 904 machines (Orlyonok) and one Project 903 craft (Loon’). Quite clearly, for many they were a thorn in their flesh. Gradually, the ekranoplans began to sink into oblivion – there were many other things to think of. The vehicles gradually fell into disrepair to the point of no longer being airworthy. Finally, in 1998 the command of the Russian Navy issued an order requiring the Orlyonok WIG vehicles to be written off on account of their alleged unsuitability for repairs and refurbishment. The Orlyonok served as a basis for several versions intended for civil applications.
In the late 1980s the work of the Central Hydrofoil Design Bureau on WIG vehicles intended for military application led to the creation of a unique machine – a missile strike ekranoplan. Bearing the manufacturer’s designation ‘Project 903′, it was subsequently named Loon’, which means ‘hen-harrier’ (according to some sources, it was initially named Ootka – ‘duck’, but this sounded totally unwarlike and could also be interpreted as ‘canard’, ie, something bogus). This machine with an all-up weight of 380 t (838,000 Ib), a hull length of 73 m (240 ft) and a wing span of 45 m (148 ft) was launched in 1987. Its design was based on the layout which had already been tried and tested on such vehicles as the KM and the Orlyonok, that is to say, the ‘aircraft’ layout – that of a monoplane with wings of trapezoidal planform and aT-tail.
The Loon’, however, differed a lot from its predecessors – the entire powerplant comprising eight 13,000-kgp (28,660-lb st) Kuznetsov NK-87 turbofans was located on the forward fuselage. Thus, the engines served both as booster (blower) engines and cruise engines. This was apparently associated with another special feature of the machine – the placement of its offensive armament. Mounted dorsally on the fuselage were six launch containers for 3M80 Moskit (Mosquito) supersonic anti-shipping missiles (NATO code name SS-N-22) developed under the guidance of Aleksandr Va. Berezniak. During the launch of these missiles there was a risk of the combustion products being ingested by engines previously placed high on the tail unit, which could cause the engines to flame out. Transferring all the engines into the forward fuselage eliminated this danger.
As distinct from the low-wing Orlyonok, the Loon’ had mid-set wings; otherwise, they were similar to those of its predecessor and were of multi-spar metal construction which was made watertight. Placed on the bottom of the hull was a hydroski device intended to cushion the impact when alighting on water.
The Loon’ was equipped with a radar for air and surface targets detection and with a navigation radar, as well as with an ECM suite. The defensive armament consisted of two gunner’s stations borrowed directly from the II’yushin IL-76M military transport, each with a UKU-9K-502 turret mounting two 23-mm (.90 calibre) Gryazev/Shipoonov GSh-23 double-barrelled cannons.
The machine’s performance included a maximum speed of 500 km/h (310 mph), a cruising altitude of 5 m (15 ft) and a range of 2,000 km (1,240 miles). It had an endurance of 5 days when afloat. The vehicle had a crew of 15.
Armed with Moskit anti-shipping missiles, the WIG vehicle flying at ultra-low level at a speed of 350-400 km/h (218-249 mph) could deal a devastating blow to the potential enemy’s naval units and leave the scene unimpeded. According to Russian press reports, ‘the Project 903 ekranoplan No. 5-31 underwent operational testing in 1990-1991′. In the course of this trial operation live missile launches were made from the onboard launch tubes, as testified by available photos. The machine met the design requirements, but it was ill-fated. Initially, in line with the provisions of directive No. 252-73 issued by the Communist Party Central Committee and the Soviet Council of Ministers on 26th March 1980, the programme of warship construction envisaged the completion of four Project 903 machines in the 12th and 13th five-year plan periods (1981-1990); later the planned figures were increased. Plans were in hand for the construction of six Project 903 WIG vehicles up to 1995 and another four machines of this type before 2000, However, in the late 1980s there came a change of heart towards the WIG vehicles in the command of the Navy. In 1989 it was decided to limit the construction of the attack WIG machines to just one example. A decision was taken to convert the second example of the Loon’, then under construction, into a SAR vehicle.
As for the sole example of the Loon’ combat ekranoplan, it was withdrawn from service and is stored in Kaspiysk. According to one document, ‘in order to preserve the missile-armed ekranoplan, the Commander-in-Chief of the Navy took a decision providing for its preservation at the territory of the 11th Air Group and for transforming it into an air base (for storage of the ekranoplan), with one crew complement to be retained at the base’.