The History of Kamov Company

All the World's Rotorcraft

Part I | Part II | Part III | Part IV | Part V

4. The main stages of the creative work of the OKB led by N.I.Kamov

Shipboard operations with the Ka-10 showed the necessity to start the construction of a new rotary-wing machine capable of lifting greater loads and less restricted by weather conditions. It was to have an enclosed cockpit fitted with the necessary equipment and providing normal conditions for the pilot, allowing him to function properly. These requirements were met by the Ka-15 which, like its predecessors, featured the co-axial layout. It was a two-seat helicopter with side-by-side seating for the pilot and a mission equipment operator or a passenger.

The Ka-15 made its first flight on April 14, 1953 at the hands of test pilot D.K.Yefremov. State acceptance trials were completed in 1955, and next year the helicopter entered production at aircraft factory No.99 in Ulan-Ude. The Ka-15 evolved into a number of specialized versions, including the multi-purpose Ka-15M, the UKa-15 dual-control trainer version and the four-seat Ka-18. In each case prototype construction began at factory No.82 in Tushino and was completed at the OKB's own experimental shop near Ukhtomskaya railway station.

The leadership of the Soviet Navy ordered a fly-off between the Ka-15 co-axial helicopter and the Mil Mi-1 single-rotor helicopter, during which both types operated from the cruiser "Mikhail Kutuzov". By virtue of its small size and manoeuvrability the Ka-15 successfully performed take-offs from and landings on the ship's small helipad even in sea state 6 conditions. Conversely, the Mi-1 was considerably hampered by its long tail boom and tail rotor and could not operate when air turbulence and pitching and rolling motion of the ship were present. The results of the fly-off finally convinced the Navy that choosing the co-axial layout for a shipboard helicopter was the right decision.

Kamov Ka-15

Kamov Ka-15
( 1953 )

The ASW version the Ka-15 was fitted with two RGB-N sonobuoys or with the SPARU-55 automatic airborne receiver unit. One of such helicopters dropped sonobuoys in the designated part of a sea, the other received information from them about the presence or absence of a submarine. Once a submarine was detected, a third Ka-15 equipped with the OPB-1R sight and two 50-kg depth charges entered service. The first units equipped with Ka-15 helicopters were formed in 1957-58. In 1958 work commenced on equipping the destroyer "Svetly" (Project 57) with a helipad. In 1960-1961 the Navy took delivery of eight Project 57 ships featuring helipads, support equipment for helicopter operations and accommodation for pilots and maintenance personnel.

The Ka-15 and its versions remained in service for almost 20 years. Between 1958 and 1963, rotor blades of new design were developed, tested and introduced on the Ka-15M and the Ka-18. They were made of composite materials which improved the lift/drag ratio of the rotor and extended the service life of the blades. In 1958-59 test pilot V.V.Vinitsky established two world speed records on the Ka-15M. In 1958 the Ka-18 was awarded a Gold Medal at the World Exhibition in Bruxelles. The Ka-15 marked the beginning of co-axial helicopters operations in the Navy and Civil aviation, the Soviet state airline. As was universally acknowledged, V.B.Barshevsky, M.A.Kupfer, N.N.Priorov, A.J.Vlasenko and D.K.Yefremov made major contribution to the development of the Ka-15.

In 1955, without waiting for the construction work at the production base to be completed, the OKB moved to the vicinity of Ukhtomskaya railway station - to the place of permanent deployment, in military parlance. Over the next five years the engineers accomplished the truly Herculean task of organizing experimental aircraft production. The experimental factory and the design office were well equipped and the specialists were very proficient to fulfil the most complex work involving the use of state-of-the-art technologies. The availability of the flight test facility provided with modern equipment, including rigs for full-size tests and sites for service-life test runs, ensured high quality of testing and speedy completion of the development phase of rotorcraft. Construction of social amenities and facilities for the personnel proceeded in parallel.

Both then and in subsequent years the OKB enjoyed invaluable assistance from research and development establishments of the aircraft industry and of the Ministry of Defence. These included TsAGI (the Central Aero- and Hydrodynamics Institute named after N.Ye.Zhukovskiy), LII (the Flight Research Institute named after M.M.Gromov), NII VVS, TsIAM (the Central Aero Engine Institute), VIAM (the All-Union (later All-Russian) Institute of Aviation Materials), SibNIA (the Siberian Aviation Research Institute named after S.A.Chaplygin), the 30th TsNII MO (30th Central Scientific Research Institute of the Ministry of Defence), NIAT (the State Scientific Research Institute of Aviation Technologies), Nil ERAT WS (the Air Force Scientific Research Institute for Aircraft Operations and Repair), and others. N.I.Kamov paid special attention to recruiting highly qualified personnel for the OKB. At his initiative a branch of the Moscow Aviation Institute was established on the territory of the company in 1963. Skilled personnel and the constantly enhanced scientific, technical and intellectual potential were the foundation of the OKB's achievements in the design of unique rotorcraft.

A major milestone in the history of the naval combat shipboard and carrier-borne aviation was the Ka-25 helicopter. Powered by two GTD-3F turboshaft engines developed by V.A.Glushenkov, the Ka-25 first flew in 1961 with test pilot D.K.Yefremov at the controls. This was the first dedicated combat helicopter designed in our country. The emergence of the Ka-25 was inseparably connected with the creation of the ocean-going Navy and with ensuring a reliable anti-submarine defence. It was designed for destroying atomic submarines. The State acceptance trials of the Ka-25 were completed in 1968.

All in all, 18 different modifications of the Ka-25 were designed and built, i.e. the Ka-25PL basic ASW version, the Ka-25Ts over-the-horizon (OTH) targeting version, the Ka-25PS SAR version, the Ka-25BT mine countermeasures version, the civil Ka-25K flying crane etc. The Ka-25PL was exported to India, Syria, Bulgaria, Vietnam and Yugoslavia. 12 Soviet Navy Ka-25BTs took part in minesweeping operations in the Suez Gulf.

For the Ka-25 the OKB developed a co-axial rotor system which was fully up to the latest achievements of scientific knowledge and to the technologies currently in use in the country. In subsequent co-axial helicopter types only minor changes were made to some elements of the rotor system to improve their design, production technologies and maintainability. The co-axial helicopter's aerodynamically symmetrical layout, coupled with the autopilot, sophisticated avionics suite and good handling qualities, enabled one pilot to fulfil long-endurance combat tasks under any weather conditions.

For the first time, Kamov designers fitted a rotary-wing aircraft with a mission avionics suite and weapons system which allowed the helicopter to navigate above water surface devoid of any reference points and fulfill the task of locating and destroying a submarine, both in manual and automatic mode. They achieved this by skilfully joining the efforts of a large number of cooperating enterprises. During prototype construction the designers - for the first time in OKB history - had to adapt it to the ship. One of the big problems was the fact that space on a ship is extremely limited and every square metre has to be used to the full. The company's specialists were well aware of that - and achieved an excellent result: the Ka-25's take-off weight increased 5-fold compared to that of the Ka-15 for an increase in dimensions by a factor of only 1.6. To reduce the rotor-craft's dimensions for hangar stowage during cruise, the designers created an electromechanical rotor blade folding system. This made the helicopter quite compact; e.g., overall length with the blades folded was only 11.0m.

Even in retrospective, with our present-day knowledge, one cannot help feeling respect for the specialists and leaders who assumed responsibility for the implementation of the shipboard combat helicopter concept. Inevitably, there were sceptics at the time among Ministry of Aviation Industry, Air Force and Navy officials who though it impossible to cut through the interdepartmental bureaucratic red tape. Moreover, critics questioned the soundness of the co-axial helicopter layout. And yet, Kamov and his co-workers succeeded in constructing a rotorcraft that laid the foundation for a large-scale introduction of co-axial helicopters into service.

The Ka-25's flight test programme revealed that each type of warship had its peculiarities as far as pitching and rolling characteristics and airflow over the deck were concerned. Development of methods of helicopter landings on ships of different categories in daytime and at night with the ship under way and at rest, as well as water landing techniques, was accomplished by test pilots V.M.Yevdokimov and N.P.Bezdetnov. They conducted a large amount of test work with a view to evaluating the automatic engine control system, mastering single-engine piloting techniques and making engine-out landings in autorotation mode without a landing run.

The reliability of the Ka-25 during shipboard operations was amply demonstrated during numerous sea and ocean cruises in which Kamov specialists participated. The first ocean cruise of the Ka-25 took place in April-September 1967. The helicopter operated from the flight deck of the "Tobol" mothership, having logged 100 flight hours during the cruise. Deployment of helicopters on ships - both singly and in groups - was subjected to a very stringent testing on ships of various types, including the well-known ASW cruisers "Moskva" and "Leningrad". The Ka-25 passed this test with flying colours.

The Ka-25 ensured the navigation of ships in the Polar North, operating from the nuclear-powered icebreaker "Sibir". As a rule, ice patrol and guidance of ships through icefields was conducted under adverse weather conditions with limited visibility. At the time, this complicated task could only be tackled by the Ka-25 fitted with modern avionics, including a 360 search radar. It should be noted that the Ka-25 was the first extremely compact co-axial helicopter in the world to accommodate a powerful search radar and ensure its effective operation. The Ka-25 is undoubtedly a unique helicopter. Quite a few features put into effect by the OKB's specialists in the process of its design can be described as "a world's first".

Two versions of the helicopter were designed in parallel: the Ka-25PL and the Ka-25Ts. The former is a submarine hunter equipped with weapons, the latter is a reconnaissance platform tasked with seeking out surface targets and designating them to the powerful artillery and rockert weapons placed on ships and at coastal bases. The airframe, rotor system and powerplant of these helicopters were designed with a maximum degree of commonality.

At various stages of construction and development of the Ka-25 the work was led by deputy chief designers N.N.Priorov (design and construction), I.A.Ehrlikh (State acceptance trials and final development), V.N.Ivanov (series production and operation). Yu.A.Lazarenko and Ye.G.Pak were the leading designers, while G.P.Stoletov was the leading engineer responsible for the trials programme.

At its own initiative, the OKB made an attempt to build a civil derivative of the Ka-25 - the Ka-25K intended for cargo and passenger transportation and for flying crane operations. In 1967 the Ka-25K prototype was successfully demonstrated in the static display and in flight at the Le Bourget Air Show. The presentation of a co-axial helicopter - moreover, in such a "heavy" weight category - became an event quite out of the ordinary for the world aviation community, as the comments of helicopter design specialists testified. During refuelling stopovers on the way from Moscow to Paris and back the helicopter invariably became the centre of attention.

The Ka-25K had an operator's cockpit suspended under the forward fuselage for controlling the machine during operations with slung loads. It could replace the remarkably versatile but obsolete piston-engined Mi-4 helicopter, production of which had ended in 1966. Suffice it to say that, having an identical take-off weight, the Ka-25K could transport a 2000kg load compared to 1300kg for the Mi-4. Design work on the Ka-25K was led by deputy chief designer I.A.Ehrlikh; the leading designer was S.V.Mikheyev. Yet, regrettably, this version of the helicopter did not enter service because of a Government decision to place an order in Poland for the design of the PZL W-3 "Sokyl" helicopter in the 6000-7000kg class.

In recognition of their part in the creation of the Ka-25 helicopter intended for onboard single and group deployment as part of warship projects, State Prizes were awarded to N.I.Kamov (in 1972), V.N.Ivanov (in 1972) and Yu.G.Sokovikov (in 1985). Many other members of the OKB staff, including A.I.Vlasenko, A.A.Dmitriyev, G.I.Ioffe, G.I.Karpov, I.G.Mchedlishvili, G.I.Kadykov etc, received Government awards.

The development of helicopter design at home and abroad opened up the prospects of using rotorcraft as a means of transportation of heavy-weight cargoes on the vast territory of the USSR. In the mid-50s, in response to a GOR issued by the Ministry of Defence, the OKB took a revolutionary decision to build an experimental compound helicopter, the Ka-22. Dubbed "Vintokryl" (lit. "screw-wing"), it featured two lifting rotors and two tractor propellers for forward thrust, both mounted at the wingtips. This was an aircraft of a basically new type for our country's aviation, combining the advantages of the helicopter capable of vertical take-off and landing and of the aeroplane possessing greater lifting capacity, range and speed as compared to the helicopter.

N.I.Kamov focused the attention of the Vintokryl's creators on the design of high-speed lifting rotors which would enable the compound aircraft to cruise at 400-450km/h. At high forward speeds the wing was intended to decrease rotor disc loading as much as possible, ensuring low drag factors. This allowed the tips of the main rotor blades to reach the speed of sound and the rotor to work in a mode close to autorotation. N.I.Kamov's decision to retain minimum required rotor disc loading at high speed sufficient for damping rotor oscillations and for ensuring stable rotor behaviour during manoeuvers proved to be of fundamental importance.

Development and construction of the Ka-22 called for a lot of theoretical and experimental work. Under the leadership of S.Ya.Finkel' a whole set of methods was developed to determine the aircraft's parametres, rotor blade configuration, the basic performance characteristics of the rotorcraft and its aerodynamic design, to calculate aerodynamic loads, aerodynamic balancing etc. Special research was made to ensure optimum characteristics in transitional flight modes, to select structural stiffness characteristics of the airframe components, to prevent rotor blade flutter and "ground resonance". Much attention was paid to the problems associated with the compound rotorcraft's stability and controllability. Kamov's engineers succeeded in corroborating the results of theoretical methods of calculation through the use of numerous models, test rigs and special devices, as well as in the process of flight tests. A major contribution to the creation of the Ka-22 was made by S.B.Garshtein, AI.Dreizin, Z.Z.Rosenbaum, A.G.Satarov, E.A.Petrosian, L.A.Potashnik, V.N.Kvokov and other members of the OKB staff, as well as by TsAGI specialists M.K.Speransky, I.O.Faktorovich and E.V.Tokarev.

Work on the unique powerplant and systems of the aircraft was headed by deputy chief designer N.N.Priorov, and deputy chief designer M.A.Kupfer was responsible for the rotor system and the airframe. Yu.S.Braginsky was appointed Ka-22 leading designer and V.B.Al'perovich was the leading engineer of the flight test programme.

Test pilot D.K.Yefremov was the first to put the unusual aircraft into the air on August 15, 1959. First deputy chief designer V.I.Biryulin was responsible for all the work on the compound helicopter. LII staff, including test pilots Yu.A.Garnayev and V.V.Vinitsky, rendered great assistance to the Kamov organization in perfecting the Vintokryl's stability and handling, especially at low transitional flight speeds.

In 1961 an OKB test crew captained by D.K.Yefremov set eight world records on the Ka-22, including the world helicopter speed record (356km/h) and the payload to 2000m altitude record (16485kg); the latter achievement still stands as of this writing. The compound helicopter was impressive by any standards: maximum take-off weight was 42500kg; the cargo cabin was 17.9m long, 2.8m high and 3.1m wide. To get an idea of the magnitude of the task solved by the OKB, suffice it to compare the maximum take-off weight of the Ka-22 and that of the then biggest Kamov helicopter, the Ka-25 (7000kg).

Sadly, the fate of the Ka-22 was sealed by two tragic crashes, the cause of which could not be determined beyond doubt at the time. After that, the Air Force leadership could not overcome the mistrust that had arisen towards this flying machine and never gave the OKB a chance to complete development. Nevertheless, the design, construction and testing of such a complex and large rotorcraft took the company's specialists to a new, higher scientific and technical level.

The year of 1956 saw the beginning of the wide-scale application of helicopters in the Soviet national economy. The need arose for helicopters capable of spreading fertilizers in the fields, orchards and vineyards and of combatting pests and weeds. To this end Ka-15M and Mi-1 helicopters were fitted with agricultural equipment. Operational experience gained with these types revealed the need for a dedicated helicopter with a bigger cargo-lifting capacity for performing a wide range of agricultural duties. This requirement was met by the Ka-26 featuring a modular design with interchangeable mission equipment (the "flying chassis").

In January 1964 the Soviet government issued a directive on the creation of the multi-purpose Ka-26 in two versions: the agricultural version capable of carrying 600-700kg of chemicals and the transport version for carrying passengers over distances of up to 400km. At the time our Civil Aviation already operated the agricultural version of the Mi-2 multi-purpose helicopter. The Kamov OKB was faced with the task to build a more cost-effective aircraft and did so with success. The Ka-26 design effort was headed by deputy chief designer M.A.Kupfer; Yu.I.Petrukhin was the leading designer and V.S.Dordan the leading engineer in charge of the flight tests.

The first circuit flight of the Ka-26 took place on August 18, 1965; the prototype was flown by test pilot V.V.Gromov. The State trials were successfully completed in the autumn of 1967 and production was launched in the town of Kumertau at a factory which had been purpose-built in 1962. The leaders of the OKB and its specialists rendered invaluable assistance in the setting up and development of the new aircraft factory. Their efforts were not wasted - the Kumertau Aircraft Production Association is currently continuing production of helicopters bearing the Kamov emblem, albeit helicopters of a new generation.

Between 1967 and 1970 several modifications of the Ka-26 were designed and tested: a shipboard version, an air ambulance version, a geological survey verson, a "flying crane", a highway patrol version etc. In its basic configuration the helicopter can be fitted with quickly detachable equipment packages, such as: passenger (cargo) cabin, cargo platform, hopper and spraybars for crop-spraying etc, and thus can be converted into any of the required versions within 1.5-2 hours. Due to the Ka-26's unusual modular design the specific versions were not allocated designations of the generally adopted style (i.e., with suffix letters), although they were just as numerous as, for example, those of the Mi-2 helicopter in the same class.

In the Ka-26 helicopter the Kamov OKB made its first large-scale use of parts and subassemblies made from composite materials. These included rotor blades, engine cowlings, the hopper for chemicals etc. The main achievement, however, was the organization of mass production of glassfibre rotor blades which ensured stability of aerodynamic characteristics under varying climatic conditions. Composite rotor blades had 5000-hour service life; in contrast, the metal blades of contemporary helicopter rotors had service life of less than 600-800 hours. The design and production technology of the blades have been patented in five countries outside the former Soviet Union; this know-how formed the basis for the production of improved new-generation rotor blades.

Single-rotor helicopters with a tail rotor are in production in Russia, the USA, France, Germany, Great Britain, Italy and elsewhere. It is an open secret that the helicopter design bureaux of these countries make use of the achievements of their competitors. When designing co-axial helicopters, N.I.Kamov's OKB virtually does not have to borrow from foreign experience, because it is exactly the Kamov OKB that "dictates the fashions" in this field. The company's rotorcraft possess so-called "patent purity". It was not least this circumstance that enabled the Ka-26 as the only Soviet helicopter to be certificated in accordance with US FAR 29 airworthiness regulations. It was also the only Soviet helicopter to be sold abroad on a commercial basis; the Ka-26 was exported to 17 foreign countries. For more than 30 years it has been doing its job with dignity. The total flying hours amassed by the type amount to 2,907,000 hours. In 1980 and 1982 the Ka-26 established five world records.

Although the USSR was a world leader by then as far as the scale of agricultural flying is concerned, its agricultural aircraft inventory (the An-2 aeroplane and helicopters) did not have the potential to increase the total serviced area and reduce the cost of the work. Hence in the early '70s the Ministry of Civil Aviation issued an outline specification for the design - on a competitive basis - of a special aircraft capable of carrying 1500-1800kg of chemicals and reducing work costs by 20-25% as compared to the An-2.

A group of enthusiasts from the the OKB staff suggested that N.I.Kamov take part in the competition with an autogyro of the "flying chassis" type similar to the Ka-26 helicopter. The submitted project of an agricultural autogyro powered by a single turboprop engine with a pusher propeller met the specification. The new-generation autogyro was superior to a new STOL aeroplane in manoeuvrability and flight safety at low speeds and in low-level flight. It posed considerably more modest demands to runways. It had no equals among the contenders as far as cost-effectiveness and flight safety were concerned. Alas, the unusual project never got off the drawing board.

It is no secret that the life cycle of any aircraft type is limited. A moment came when further upgrades of the Ka-25 combat helicopter ceased to give the desired result. Besides, a new helicopter was required to equip the Soviet Navy's aircraft carriers. To meet a Navy specific operational requirement (SOR) the OKB started work in 1970 on a next-generation shipboard combat helicopter which bore the manufacturer's designation Ka-252. The SOR demanded that the rotorcraft has the same overall dimensions as the Ka-25; this was dictated by the confines of deployment on existing ships of various categories. This was no easy task, especially bearing in mind that it was necessary to considerably enhance the effectiveness of the onboard avionics suite and weapons system so as to boost the Navy's ASW capability.

The professional staff of the OKB began painstaking work under the leadership of the experienced chief designer, Doctor of Technical Sciences N.I.Kamov. A born designer, he believed that there were no trilling matters in his work. He was the world's only specialist in the field of helicopter design who succeeded not only in substantiating theoretically the advantages of the co-axial helicopter layout but also in putting it into practice on helicopters designed for various roles. N.I.Kamov and his co-workers' greatest achievement is the development of non-traditional designs and of methods of producing long-life rotor blades made of composite materials.

N.I.Kamov's remarkable personality irresistibly attracted people who, like him, were mad about aviation. The position of the director of the OKB's experimental factory was then held by N.N.Priorov. The flight test facility was headed by V.B.Alperovich, an experienced test pilot. The basic branches of the work were led by the talented deputy chief designers V.I.Biryulin, M.A.Kupfer, V.N.Ivanov, I.A.Ehrlikh and S.N.Fomin.

Research on the aerodynamical and dynamical problems of co-axial helicopters, development and improvement of aerodynamic reseach methods and methods of calculation of stability and controllability characteristics of rotorcraft was the responsibility of the OKB division under E.A.Petrosian. Many workers of this division were world-class specialists; some of them went on to become prominent scientists in their field. A.I.Dreizin and G.V.Yakemenko headed the development of structural strength calculation methods for Kamov hardware, methods of calculating frequency characteristics, loads and stresses in rotor blades, methods of preventing rotor blade flutter and the ground and air resonance. The need to design naval helicopters featuring sophisticated avionics and weapons integrated systems and capable of solving a wide range of combat tasks under any weather conditions (including automatic weapons launch) meant that a dedicated division of the OKB had to be created. Undoubtedly, many company specialists working in other divisions and departments also had a hand in the design, construction and testing of the new helicopter but their influence on the appearance of co-axial helicopters was much smaller.

Thus, a new school of scientific development and practical rotorcraft design emerged under the leadership of chief designer N.I.Kamov. For a long time, one could only make guesses about its potential due to the "black" nature of much of the work conducted in the OKB. Only recently, when the cloak of total secrecy was lifted, did the Kamov school receive the world recognition it deserves.

The first flight of the Ka-27 (Ka-252) combat helicopter took place on December 24, 1973; the helicopter was flown by the chief-pilot of the OKB Ye.I.Laryushin. Sadly, the founder of the company did not live to see this stirring event; he passed away on November 24, 1973. Further work on the helicopter was continued by his co-workers I.A.Ehrlikh, M.A.Kupfer, Yu.G.Sokovikov, Ye.G.Pak, Yu.A.Lazarenko, M.Ye.Nemirovsky, as well as N.I.Kamov's successor Sergei Viktorovich Mikheyev.

N.I.Kamov attached great importance to the preservation of the company's historical heritage. In 1971 he decided to establish a company museum. The museum was officially opened on August 18, 1972; the founder of the company was its first visitor. The museum not only collects and carefully preserves materials on the history of helicopter construction, but also willingly makes them accessible to a wide circle of aviation specialists and enthusiasts. In 1974 the OKB was named after N.I.Kamov. The memory of Nikolai Il'yich Kamov lives on in the rotorcraft built by him, as well as in the newly created helicopters bearing the Kamov logo.

Part I | Part II | Part III | Part IV | Part V

From "OKB Kamov. 50 years" by G.I.Kuznetsov