Rostislav Evgenievich Alexeyev
Wing-in-ground-effect craft making use of a dynamic air cushion are vehicles operating in close proximity to a supporting surface. This is usually water, but basically it makes no difference whether a WIG craft is operating over water or over land – provided that the ground surface is sufficiently even and flat.
A feature common to an aircraft and a WIG craft is wings generating lift due to aerodynamic forces. However, in the case of the WIG craft this lift is augmented owing to the ground effect created by compression of the ram air stream between the wings and the supporting surface. A higher lift/drag ratio enables a WIG craft to obtain the same lift at lower speeds and lower engine power compared to aircraft. As a result, the WIG craft are, in principle, more fuel-efficient compared to aircraft.
Since large flat areas on land are not a common occurrence, WIG craft are in most cases intended for use over water. Operation from the surface of lakes, rivers or seas of necessity introduces some features of waterborne vessels into the design of WIG vehicles. Historically, a number of WIGs emerged as a kind of attempt to lift water-borne craft out of the water for the purpose of achieving greater speeds, and in many cases WIG craft were built at shipyards. Small wonder that the question is posed sometimes whether one should regard these new craft as very low-flying aircraft or as ships that have lifted themselves out of the water.
It would appear that both definitions might be appropriate, since the concept of WIG vehicles embraces a wide variety of craft featuring quite substantial differences. They may tend to be closer to one or the other of the two extremes, but, generally speaking, they are always something of a hybrid. On the one hand, a WIG vehicle in cruise flight is subjected to aerodynamic forces, much in common with conventional aircraft, while the hydrodynamic forces act on it only during take-off and landing – or rather alighting. On the other hand, WIG craft operating in close proximity to the water surface in a marine environment have to be subjected to the same rules and requirements as conventional marine vessels in terms of traffic safety.
The latter consideration has played an important role when it came to establishing a formal classification of WIG vehicles with a view to adopting rules concerning their certification and safety regulations. Three basic categories have been formally adopted for this purpose.
The first of them (Type A) encompasses vehicles that can be operated only within the height of the surface effect. They usually feature wings of low aspect ratio (up to 1) and are fitted only with a rudder, there being no elevator; the ‘driver’ (or should we say helmsman?) does not have to possess piloting skills and steers the vehicle in much the same way as an ordinary speedboat. In Russian parlance, such vehicles are termed Dynamic Air Cushion Vessels, or WIG vessels (ekranoplan boats). Among Russian designs, such examples may be cited as the Volga-2, Amphistar and Raketa-2.
The second category (Type B) includes vehicles which are capable of leaving the surface effect zone for a short while and making brief ‘hops’. The altitude of such a ‘hop’ shall not exceed the minimum safe altitude of flight for aircraft, as prescribed by International Civil Aviation Organisation (ICAO) regulations (150 m/500 ft). In Russian parlance such vehicles are regarded as WIG craft (ekranoplans) proper; they feature wings with an aspect ratio of up to 3 and are provided with elevators. They are controlled by pilots. Among Russian designs this category is represented by the Orlyonok, KM, Strizh, ESKA-1 etc.
The third category (Type C) covers WIG vehicles capable of flying outside the surface effect zone for a considerable time and of climbing to altitudes in excess of the minimum safe flight altitude for aircraft, as prescribed by ICAO regulations.
This classification subdividing the WIG vehicles into types A, B and C was formulated by Russian organisations and submitted by Russia to the International Marine Organisation (IMO) and ICAO for their consideration. Thanks in no small degree to determined efforts of the Russian side it has proved possible to reach within the framework of IMO an agreement on a number of basic issues pertaining to legal, technical and operational aspects of WIG craft. For the first time international documents were evolved that provide rules for commercial operation of WIG craft and for their safety. These documents represent an important milestone. For the first time they have given an expression at a high level for an international recognition of WIG craft as a new and promising means of maritime transport and provided a legal basis for its further development and commercial operation on international sea routes.
The early research on ground effect and of efforts aimed at creating practicable WIG vehicles dates back to the 1920s and 1930s when work in this field was started in several countries (as is well known, the first self-propelled WIG vehicle was built by T. Kaario, a Finnish engineer, in 1935). The Soviet Union was among these countries. Theoretical and experimental work in this direction was started in the USSR in the 1920s (experimental work by B. N. Yur’yev, 1923). Further work followed in the late 1930s, when a whole set of theoretical studies and experiments in the field of ground effect research was performed by Yakov M. Serebriyskiy and Sh. A. Biyachuyev. The results of this work were published in specialised literature.
In the late 1930s the first steps in practical design of WIG craft in the USSR were made by Pavellgnat’yevich Grokhovsky, an aviation engineer and inventor renowned for his energy and innovative ideas.
However, it is Rostislav Yevgen’yevich Alexeyev (1916-1980), an outstanding scientist and designer, who must be credited with having played a paramount, decisive role in shaping the course of research, design and construction of WIG vehicles in Russia. His was the conceptual approach and design philosophy; he may truly be regarded as the founder of the Russian wingship construction. Alexeyev started his activities as a builder of hydrofoil ships in his capacity of the chief of the Central Hydrofoil Design Bureau (TsKB po SPK – Tsenfrahl’noye konsfrooktorskoye byuro po soodahm na podvodnykh kry/’yakh) set up in Nizhniy Novgorod. An impressive range of highly successful hydrofoil vessels designed under his guidance was developed 4 and put into operational service. Yet, it was precisely his work on WIG craft – work veiled in utmost secrecy for many years – that was destined to become the most prominent and significant part of his creative activities and represented a major contribution to the world’s technical progress.
The Central Hydrofoil Design Bureau has been actively engaged in WIG craft design since the early 1960s. The work was based on the concept of autostabilisation of the wing of a WIG vehicle relative to the interface between the supporting water surface and the air. This concept proved sound and was subsequently incorporated in all WIG projects issued by the design bureau. On its basis a search was initiated for suitable aero-hydrodynamicallayouts; initially, one of these featured two sets of wings arranged in tandem. The first 3-ton (6,600-lb) ekranoplan built in 1961 was fitted with two sets of wings. Research revealed that the tandem layout is practicable only in a very close proximity to the surface and is unable to ensure the necessary measure of stability and safety, once the craft leaves this close proximity. Experiments with one of these tandem-wing machines ended in a crash. R. Alexeyev arrived at the decision to make use of a classic aircraft layout (one set of wings and a tail unit) which was to be subjected to modifications designed to ensure stability and controllability during cruise flight in ground effect. In particular, low-set or mid-set wings of much lower aspect ratio (around 3) were adopted. An important feature was the use of an outsize horizontal tail; it was to be placed sufficiently far aft and high up relative to the main wings so as to minimise the influence of downwash induced by the wings depending on the flight altitude and pitch angle. Ten experimental WIG vehicles featuring this layout were built by the Central Hydrofoil design Bureau, their weight and dimensions growing with every successive machine. These were the machines in the SM series (SM stands for samokhodnaya model’ – self-propelled model), with an all-up weight of up to 5 tonnes (11,000Ib).
Design experience gained by R. Alexeyev in developing these machines enabled him to take a bold decision to initiate the design of gigantic WIG vehicles with an all-up weight of more than 400 t (880,000 Ib). In 1962 the Central Design Bureau was engaged in project work on a combat WIG craft intended for ASW weighing 450 t (990,000 Ib); two years later the design team in Nizhniy Novgorod started designing the T-1 troop transport and assault WIG craft.
It should be noted that the very considerable scope attained by the activities of the Central Hydrofoil Design Bureau was due to the fact that the new means of transport had attracted much interest on the part of the military. As a consequence, for many years this work was highly classified. Thus, construction of WIG vehicles in the Soviet Union got a boost from military programmes. In the opinion of military specialists both in the Soviet Union (and nowadays in Russia) and in the West, large WIG vehicles can be employed for a wide range of missions in the armed forces, notably in the Navy. These include troop transportation, anti-submarine warfare (ASW), anti-shipping strikes with guided missiles etc. The most ambitious projects envisaged the use of WIG craft as flying aircraft carriers! An inherent advantage of WIG vehicles when used in warfare is their ability to remain undetected by enemy radar thanks to the low altitude of their flight; the lack of contact with the sea surface makes them undetectable by acoustic means (sonar devices). WIG vehicles are capable of operating not only over water expanses but also over snow-covered stretches of land and over ice fields. This makes them eminently suitable for use in Polar regions. Their high speed ensures their quick response to the changing battlefield situation, and their high load-carrying capacity enhances their capability for accomplishing various missions and carrying a wide range of weapons.
In assessing the suitability of WIG craft for ASW, one should bear in mind that, owing to their low flight altitude, WIG vehicles cannot be equipped with sonobuoys. However, they possess a wider range of capabilities for making use of a dunking sonar when afloat. Moreover, thanks to their big dimensions they can, in principle, be fitted with ASW weapons normally carried by surface ships, to be used without getting airborne.
WIG vehicles are superior to amphibious aircraft in sea-going capabilities and endurance; they can be armed with more potent missiles possessing longer range. However, they have their limitations associated with the need for target designation from an external source (amphibious seaplanes can provide target designation for their weapons when flying at high altitude).
The projects of an ASW WIG vehicle and the T-1 troop-carrying WIG vehicle never left the drawing board. On the other hand, in 1966 the Design Bureau built, in response to an order from the Navy, the KM WIG craft (KM stands korahbl’-makef – a ‘mock-up’, ie, prototype ship). With its fuselage length of nearly 100 m (330 ft), wing span of nearly 40 m (130 ft) and all-up weight of 430 t (948,000 Ib), this gigantic machine was a unique piece of engineering. In a record-setting flight its weight reached 540 t (1,190,000 Ib), which was an unofficial world record for flying machines at the time. The KM ekranoplan, dubbed ‘Caspian Sea Monster’ in the West, underwent comprehensive testing in the course of 15 years of operation. It marked the completion of a whole range of research and practical design tasks associated with approbation of the WIG concept as a whole and evolving the scientific basis for their design, construction and testing. The results of this work made it possible to create a theoretical and methodological basis for designing and building practicable examples of WIG vehicles.
One of these was the Orlyonok (Eaglet) troop transport/assault ekranoplan with a take-off weight of 140 t (309,000Ib). It was capable of transporting a 20-tonne (44,000-Ib) cargo at a speed of 400 km/h (248 mph) to a distance of up to 1,500 km (930 miles). Three examples of the Orlyonok (Project 904) were delivered to the Navy for evaluation. Their service career proved to be far from an unqualified success. Normal operation was hampered, above all, by circumstances of bureaucratic nature. The WIG machines were operated by the Navy, yet their crews had to include pilots because in certain operational modes they had to be piloted like aircraft. However, neither the Air Force nor the Naval Aviation showed any enthusiasm for these machines and sought to ‘prove’ in every possible way that they could not be regarded as flying machines – unabashed by the fact that provision was made for operating them also out of surface effect and there were plans for long-range ferrying flights at high altitude. Yielding to this pressure, the Navy top brass then decided that WIG craft should be classed as ‘ships with aircraft-like properties’. In turn, the Central Hydrofoil Design Bureau clearly underestimated the ‘aviation’ aspect of 6 the matter and had failed to consult the Air Force on the methods of testing, which gave rise to justifiable complaints. Arrangements required to facilitate operational use of the machines delivered to the Navy suffered setbacks and delays. Series production of WIG craft for the Navy was expected to amount to several dozens of examples, but these plans failed to materialise. Introduction of new types of weaponry in the USSR, following a pattern common to many countries, depended heavily on lobbying on the part of this or that person in the top echelon. The Soviet Minister of Defence, Marshal of the Soviet Union Dmitriy F. Ustinov supported the idea of WIG vehicle construction, but he died in 1985. Sergey L. Sokolov, the new Minister of Defence, influenced by the newly appointed Commander-in-Chief of the Navy V. N. Chernavin , ordered that all the funds available to the Navy be used for the construction of submarines. A crash suffered in 1992 by one of the Orlyonok machines was hardly conducive to improving the atmosphere around their integration into the armed forces. This was further aggravated by the transfer of the WIG machines from ordinary Naval units to the Naval Aviation – airmen were not overly enthusiastic about the new hardware. Deprived of the necessary attention and supplies, the base where the WIG craft were stationed began to fall into decay. Eventually the three surviving machines (two Orlyonoks and one Loon’) were struck off charge on the pretext of difficulties associated with maintenance and repairs. That marked, for the time being, the end of operational use of transport and combat WIG vehicles in the Russian Navy.
There is an episode in the story of the Orlyonok which eloquently bears witness to the character of both the machine and its creator, Rostislav Alexeyev. During one of the test flights Alexeyev was on board. The pilot, who had little experience with this type of vehicles, impacted the machine heavily right on the crest of a wave. The crew did not grasp the situation. Only Alexeyev, who had taken a look from the upper hatch, knew what had happened. Without a word, he took over the controls, gave full throttle to the nose-mounted booster engines and steered the machine to its base which was situated 40 km (25 miles) away. Only then could the crew take a look at the machine. They were stunned by the sight: the vehicle had lost its tail! The rear fuselage complete with the tail unit and main engine had simply broken off on impact and sunk! The fact that the Orlyonok still made it safely back to base bore witness both to the designer’s presence of mind and to the machine’s qualities. However, this episode placed a welcome tool in the hands of Alexeyev’s detractors and those who were intent on closing down the work on WIG vehicles. The episode was followed by ‘administrative measures’ (ie, repercussions) which boiled down to victimising the designer. He was deprived of the possibility to make full use of his creative potential, which affected very adversely the development of the WIG-vehicle construction in the USSR and present-day Russia.
An important stage in the activities of the Central Hydrofoil Design Bureau was marked the creation of the Loon’ (Hen harrier) – a 400- tonne missile carrier armed with Moskit (Mosquito) anti-shipping missiles. It was launched in 1987. Construction of a second example of this machine was envisaged, but the collapse of the Soviet Union drastically affected the programme. The second example, already under construction, was to be completed as a search-and-rescue machine. Accordingly, conversion work was started (progress reports appeared in the press in 1994), but this project, too, stranded for a long time due to various political and economic reasons. Only quite recently was the conversion work resumed and, hopefully, has a prospect of successful completion which would result in creating an unorthodox and highly effective maritime SAR vehicle.
Rostislav Alexeyev died in 1980. Earlier, after the crash of the prototype Orlyonok, he had to relinquish the post of chief of the Central Design Bureau of Hydrofoils, and then of Chief Designer.