Мясищев 3M-M4

вали иностранцев, да и в тех случаях их помощь была больше похожа на грабеж с благотвори­ тельными целями. В частности эксплуатацией Ан-225 заинтересовались Европейское Косми­ ческое Агентство и несколько зарубежных фирм. Но денег для достройки второго самолета не дали, а лишь посулили дивиденды в отдален­ ном будущем.

Самолет Ан-225 «Мрия» очень дорог. По некоторым сведениям вся программа его созда­ ния обошлась стране в 4 миллиарда доинфляционных рублей. Недешево стоит и эксплуата­ ция шестимоторного чудовища. Способный пе­ ревозить аналогичные грузы на внешней под­ веске спецвариант Боинга-747 стоит более 100 миллионов долларов. 8 этой обстановке было ясно, что использование «Атлантов» может при­ нести коммерческую выгоду.

Самолету, который вполне было возможно продвинуть на рынок авиационно-транспортных услуг такого типа (а сегодня во всем мире эксп­ луатируется немногим больше десятка самоле­ тов, которые способны перевозить особо круп­

ные грузы) был присвоено наименование «Ат­ лант». Хотя оно использовалось лишь на выс­ тавках и презентациях, но достаточно точно от­ ражало саму идею машины, которая, как и ан­ тичный герой, могла бы держать небо на пле­ чах.

Но общие трудности переходного периода не позволили реализовать потенциал машины. В 1992 году Экспериментальный Машинострои­ тельный завод совместно с Центральным аэро­ гидродинамическим институтом и Научно-про­ изводственным объединением «Сатурн» им. A.M. Люльки начали проектирование на базе «Атлан­ та» комбинированного летательного аппарата «ЗМ-Демонстратор». Он состоит из самолета ВМ-Т и разгонной ступени с двумя криогенными ЖРД Д-57, сконструированными под руковод­ ством Люльки для «лунной» ракеты Н-1.

На спине разгонной ступени могли разме­ щаться воздушно-космический самолет типа «Хогол», «Зенгер» и т.п., экспериментальный гиперзвуковой летательный аппарат или модуль с испытуемым двигателем. С помощью «Демон­

стратора» можно можно было бы не только от­ работать ряд технических новинок, например надежный атмосферный запуск предназначен­ ных для работы в пустоте кислородно-водород­ ных двигателей, но и вести коммерческие за­ пуски небольших спутников, успешно конкури­ руя с американской космической транспортной системой «Пегас» на базе самолетов В-52 и L-1011 или российской с самолетом Ту-160СК.

В 1992 году самолет ВМ-Т был представлен на авиасалоне в Жуковском и. видимо, тогда же были сделаны первые попытки найти финанси­ рование для полномасштабной разработки сис­ темы. Поначалу интерес к теме был достаточно велик, но дело требовало реальных денег. У правительства России их не было, или просто оно не собиралось зарабатывать таким образом, куда ведь проще торговать сырой нефтью. За­ рубежные «спонсоры» тоже не торопятся вкла­ дывать кровные доллары в российские новые технологии. Так печально заканчивается исто­ рия самолета, вписавшего одну из самых ярких страниц в летописи нашей авиации.

SUMMARY

Myasishchev bombers

In February 1946 the Peoples Commissar for the Aviation industry V. M. Chrunichev signed an order disbanding OKB-482 (Experimental and design bureau # 482) led by Vladimir M. Mya­ sishchev. The Designer General was forced to become the head of Moscow Aviation Institute (MAI) aircraft construction department. OKB-482 personnel were mostly transferred to the ll'yushin design bureau although some went to Tupolev, Yakovlev and others.

Following the end of World War Two in May 1945 and the subsequent proclamation of a peacetime plan for Soviet industry, such a decision would seem logical. However the disbanding of OKB-482 was a consequence of severe competition. First of all the aviation industry had to produce new

combat aircraft. The Soviet Union was being prepared for new World War.

Strategic aviation was in the spotlight in the late 1940s. The USSR had gained a new foe, one with nuclear weapons. The Soviet Union at the time possessed neither the A-bomb nor bombers which would be able to reach the primary target.

In the meantime the United States and Great Britain had amassed powerful bomber fleets. The American Strategic Air Command had five wings equipped with the B-36 Peacemaker by the end of the 1940s. Furthermore advanced turbojet strategic bomber designs were already on the drawing boards. So the USSR could thus theoretically be subjected to intercontinental bomber attack while US bases in North America remained out of the range of Soviet bombers.

There was only one design bureau which was in a position to develop a Soviet strategic bomber at that time. It was led by the famous Andrey

| Самолет ВМ-Т взлетает с самым крупногабаритным грузом (вариант 1 П). Архив ЭМЗ им. Мясищева

VM-T aircraft performes takeoff with the largest external cargo. (Version 1GT) (Myasishchev EMZ archives)

ЩНосовая часть ВМ-Т «Атлант». Фото С. Попсуевича

Nose section of VM-T «Atlant». (Photo by S. Popsuyevich)

N. Tupolev. He had his own strong opinions about the Soviet long range aviation equipment. Firstly the Tu-4 bomber, then the Tu-85 piston engined strategic bomber? then another one with more powerful internal combustion

then currently in service. Firstly the Tu-4 comber, then the Tu-85 piston-engined strategic bomber and finally a new jet-powered bomber design would prepare the USSR for a new great war. While the West would be employing new technologies and training the pilots for jet planes, large quantities of Soviet bombers equipped with reliable piston engines would quickly destroy the rebuilt Europe and would scare off an unprepared and war-weary USA.

Being familiar with German jet designs, the I. Stalin personally ordered the development of very high performance bombers to be equipped with modern turbojets. The Government ordered OKB-156 (the Tupolev design bureau) to begin the design of a family of jet bombers. Aircraft Project 88, the future Tu-16 medium bomber, was to be the first of this family. It was however also necessary to build a bomber which would be able to reach the USA over the North Pole, drop an A-bomb and to return home. Stalin personally visited A. N. Tupolev and proposed that he create such a four-jet long range aircraft. Tupolev had been able to study this proposal thoroughly by that time and had declined. This was because Tupolev presumed no other OKB was up to such a task. But the great designer Myasishchev had his own ideas...

Один из самолетов ВМ-Т был в процессе эксплуатации дооснащен штангойтопливозаправщиком. Архив автора

One of VM-T planes was fitted with refuelling probe in service,

(The author's archives)

Long-range Bomber Theoretical Research

V. M. Myasishchev's job at the Moscow Aviation Institute was not an easy one. He had soon been displaced as head of department and was assigned control of one faculty. But Myasishchev did not waste this time. He organised the student design bureau to tackle the serious task of evaluating the feasibility heavy jet aircraft production, Many students and institute engineers became involved in this research. Amongst them was G. N. Nazarov, who knew Myasishchev from his days as an engineer at plant # 256. Concerning to new bomber layout, Nazarov's proposals were similar to his work at the

# 256 OKB-1, where heavy aircraft were designed under the tutelage of Brunolf Baade (the former Junkers designer). One of them was the medium bomber 132 project featuring swept wings and six Jumo-012 turbojets, Active cooperation with TsAGI (the Central Aerohydrodynamic Research Institute) was instituted to assist MAI personnel. A number of different layouts were considered by Vladimir Myasishchev and his colleagues. During the first stage of research two designs were examined in detail. The first featured four or six piston engines and tapered wings. This was one of the last OKB-482 projects and became Aircraft 302. The second layout was a four-engined aircraft with swept wings. The latter design would satisfy the required performance criteria. This latter design thus formed the basis of the project for a strategic long-range aircraft. It was considered and approved by the TsAGI scientific council.

The aircraft was a midwing monoplane with swept wings and tail unit. The fuselage had a high aspect ratio. Having a normal payload of 5 tons (one special bomb product 501) and cruise speed of about 700 km/h at an altitude of 12-14 km, the plane needed an operational range of 6000-6500 km. The maximum payload was 18 tons and take­ off weight was approximately about 150 t. The bomber was to be fitted with four AM-TKRD-03 turbojets being designed by MAP (Aviation Industry

Ministry) OKB-300 (known from 1949 on as the Soyuz (Union) Aviation Engine Scientific-Technical Complex). These engines offered a massive theoretical thrust of 7.5 t but their specific fuel consumption was not inconsiderable either. However the new turbojet design could be put into production very quickly by Soviet industry and the project had high priority. The bomber project was named SDB.

However aero engine industry veterans argued that the TR-3 turbojets created by OKB-165 (now the Lyulka-Saturn Corporation) were more desirable within the Ministry. Soon Myasishchev sent his technical proposal about the SDB bomber to the Aviation Industry Ministry, Perhaps V. M. Chrunichev had grown tired of Tupolev's monopoly by that time. Despite a strong competing bid, on 24 March 1951 the Government order was signed restoring Myasishchev's design bureau. The Myasishchev OKB was assigned Moscow Plant # 23 for experimental and serial production. Tupolev Tu-4 serial production at the plant was halted.

Production Project

According to the Government order all former Myasishchev Bureau designers and engineers had to be returned to the new OKB-482. The design bureau of plant # 23 was additionally staffed with young engineers. The bureau's work was Overseen by Vice-Chairman of the Council of Ministers, Defense Minister Bulganin. The Chairman of the Council of Ministers G. M. Malenkovand Chairman of the Nuclear Power Special Committee L. P. Beria were also personally interested in OKB-482's affairs. This meant that any problems were resolved swiftly in Myasishchev's design office. Usually technical

specifications were produced by the customer — the Soviet Air Force but not in this case. The Myasi­ shchev design bureau alone determined the new bomber's performance parameters. The project was allocated the designation 25 and the bomber was named M.

The first experimental aircraft had to be ready for trials by early 1953. The American firms Boeing, Douglas and Convair had already been working on similar designs for two years when the Myasishchev bomber project was started. Furthermore the Tupolev Design Bureau had begun its Tu-95 project in the summer of 1951. Myasishchev had no time to lose. The general design team was led by the very capable L. L Selyakov.

Many problems had to be overcome. The aircraft's maximum weight exceeded limits. This was partly reduced by new powerful AM-03 engines with a take-off thrust of 8750 kg. The AM-03 however was a thirsty engine and the necessary range of 12000-13000 km could not be attained. Designers had to improve the aerodynamic shape of the aircraft.

The wing was designed under the guidance of G. G. Matveev and Ya. B. Nodelman, The latter having been partly responsible for the wing design of Aircraft 88 (Tu-16). The wing of Aircraft M was a spar-box structure. The main panel splice attach­ ments were located perpendicular to stiffness axis. Being able to deform safely the wing could save weight. The wing was a very complicated structure and, for the first time ever in the USSR, it was designed with computer assistance. Estimations and wing layout were checked using special models created according to relative stiffness parameters.

Plant # 23 had to utilise many new materials and technologies. This was the plant's second technological revolution after Tu-4.

The fuselage was designed by the team led by K. I. Popov. It had two large pressurised compart­ ments. The bureau had some experience in solving such a task. But exiting the cockpit safely at high speed and altitude was a major problem. Together with other bureaus downward ejection seats were produced but trials were not very successful. Since time was short it was decided to try and iron out the bugs in the seats during aircraft plant trials.

The design of the bomb bay was confronted by many problems due to the variety of bomb load dimensions specified. The primary weapon to be carried was one nuclear bomb. Furthermore, the bomber had to carry a number of different con­ ventional bombs ranging from 250 kg to 9000 kg, naval mines, torpedoes and UB-2F Chaika (SeaGull) radio-guided bombs designed by GSNII-642 and the more powerful UVB-5 ones to be used in future.

Despite of its high theoretical performance, the bomber had to be optimised for night attack. Therefore a wide array of navigation equipment was provided for. It incorporated different gyroscopic, gyromagnetic, radio and astronomical systems. Aiming was by means of the RPB-4 radar (Rubidii MM-II (Rubidium)). Produced on the basis of the Rubidii, the radar had a second operational frequency. The RPB-4 had a higher immunity from distortion. The aiming range was around 70 km; large targets could be seen from a distance of 150180 km. Target coordinate determination errors were 75-100 m by range and 2 30' by azimuth. The radar was connected to the OPB-11c bomb-sight.

This significantly increased bombing accuracy. The RPB-4 could be employed at speeds up to 1250 km/h and altitudes from 2 km to 15 km. But bombing speed was limited to 850 km/h because of overstressing concerns with the bomb bay doors. Maximum bomb load could be achieved by using of two FAB-9000 bombs. However the bomb bay did not enable the aircraft to carry bombs normally. So, one bomb was staggered and the doors had to be the faired to accommodate it. Defensive equipment consisted of optical sight stations and the PRS-17 Argon radar sight, situated in the tail gunner's compartment. It could locate targets within a cone section 70. The radar sight was connected to the SRO-2 Chrom-Nickel (Chromium-Nickel) IFF radio station. Being equipped with not only a tail turret but also upper and lower nose turrets, the aircraft had almost no blind spots. The turrets incorporated the TKB-495 artillery systems designed by N. M. Makarov and N. M. Afanaciev from the Tula Design Bureau. The system was adopted in 1953 as the AM-23 cannon after its test programme had been completed.

The combination of a fuselage filled with new equipment, complicated powerplants and sweptwing structural strength problems meant that the gestation period of the M bomber was long. With the addition of many experimental units and details, Product IM was built. The central part of the fuselage ncorporating the wing centre section now had realistic dimensions.

The undercarriage was designed under the guidance of L. L. Selyakov and under the direct supervision of G. I. Archangelsky. Four different layouts were considered. The best performance was ascribed to a bicycle layout but this Had not yet

been developed sufficiently. Theoretically this layout suffered from a lack of stability during landing, insufficient taxiing manoeuverability, High probability of forward landing gear shimmy, high probability of skid after landing and difficulty in reaching the necessary takeoff angle of attack.

But OKB-21 Designer General Alexeev had employed such a bicycle layout in his 1-215 fighter. The 1-215 was the flying testbed for the Type 150 Bomber Undercarriage being designed by OKB-1 of Plant # 256 under guidance of B. Baade. Furthermore Alexeev suggested other designers should study his experience.

Together with Lll (Flight research institute), a special flying lab was built on the basis of a Tupolev Tu-4 bomber. It could test different arrangements of aft landing gear for the M bomber. In the end each main landing gear featured a shock strut with pivoted bogie beam and equipped with four wheels. Skid detectors were used to avoid tyres burst during landing. The auxiliary gear incorporated two bearers situated at wing tips. They would retract into tip fairings, The fairings accommodated flutter counterweights. To attain the necessary angle of attack right before takeoff, the forward landing gear was equipped with a constant force-loaded hydraulic actuator. This moved the forward part of the bogie beam up simultaneously with the aircraft's increa­ sing lift while the aircraft was still supported by the aft undercarriage. The forward gear had a steering mechanism, turning the first pair of wheels to pro­ vide ground handling for the plane. To reduce take­ off distance and landing StUM rocket assisted takeoff units (RATO) and parabrakes respectively were fitted. In the end, the StUM RATO was used in experimental service only.

Being familiar with the 150 Bomber design, Myasishchev used hydraulic boosters for the M bomber control system. They met all requirements in reducing loads on the control stick and pedals. This was very important in high speed flight. These boosters were complex and heavy, which meant more time was needed for development.

A special device was created at Plant # 23 to test and develop the boosters. It was then used as a part of the bomber's flight simulator. Additionally the Tu-4 flying lab was adapted to work out the problems. Again time was running out and unimpro­ ved boosters had to be fitted. Despite the prospect of serious problems, Myasishchev hoped make im­ provements during the plant evaluation programme.

Trials

Construction for of the M bomber for flying and static tests began in 1952 at Plant # 23. All the constituent elements of the first experimental aircraft (bu. # 4300101) had been completed by the end of November. The first B-52 had begun test flights in the USA by that time. The design bureau had to hurry. The new bomber's structural units were transported by river to the Plant # 23 flight station at Zhukovsky. Trials were to be undertaken there. It was situated on property of the Ul. The aircraft was assembled at Zhukovsky, while the test pilots were preparing with flight simulator and the bicycle gear flying lab. When ground runs had been completed the M bomber was ready for its first flight. It was made from Zhukovsky on 20 January 1953 in the hands of F. F. Opadchiy. The crewmembers were: A. N. Gratsiansky—co-pilot; A. I. Pomazunov—navigator; 1.1. Richlov—W/O; G. A. Nefedov — flight engineer. Besides them, the leading engineers I. N. Kvitko and A. I. Nikonov were also aboard. The flight only lasted ten minutes but the first problems were noted. Insignificant slip appeared because of rudder overbalancing. The cause was confirmed in the third flight when F. N. Gratsiansky had tried to switch the control off. Different structural improvements were performed after each test flight.

The first serious trouble appeared inevitably on the thirteenth. Maximum speed at different altitudes had to be defined. The aircraft was maintaining altitude when leading engineer Kvitko reported elevator sections were moving like scissors. F. F. Opadchiy decreased thrust and the malfunction disappeared. After the flight, the elevators were redesigned and they featured aluminium strengtheners to eliminate elevators splitting into sections. However, during the next flight one elevator disintegrated. The stabiliser and the rudder were damaged. The crew performed an emergency landing using the remaining elevator. The causes of the incident were insufficient control rod stiffness and errors in elevator strength analysis. When an elevator control system was introduced, improvements resulted in a maximum speed about 847km/h. The bomber's range was 8100 km with a payload of 51 and 6500 km with the maximum load. Neither the Customer or OKB-23 were inclined to further increase the aircraft's range. Furthermore, during the first experimental M trials intense shimmy vibration in the forward landing gear occurred. Following the recommendations of TsAGI engineers, a shimmy damper and smaller wheels were fitted.

The M bomber prototype made 28 (65 flying hours) tesl flights, according to plant evaluation programme. Despite many problems it was a success. On 19 September, 1953 the Central Committee of CPSU (Communist Party of the Soviet Union) and Council of Ministers of the USSR placed an order. It was made, as usual, before the plant test programme finished. The order committed Plant

# 23 to begin M bomber serial production, building three aircraft in 1954 and eight the next year. The remaining plan for 1955 had yet to be specified. The Aviation Industry Ministry order and documents of Gosplan (State Planning Committee) increased the design bureau's financing significantly.

The second aircraft (bu. # 4300102) started test flights on 23 December 1953. It flew for the first time with a crew commanded by В. К. Galitsky. The first prototype had a normal takeoff weight of 131800 kg. Its maximum weight was 181500 kg, when the theoretical maximum take-off weight was supposed to 155000 kg. When building the second aircraft the designers tried to achieve reductions in maximum weight. The fuselage was shortened by one metre. The undercarriage design was changed. A combination of flap area and angle increase improved the takeoff and landing characteristics. Furthermore, new strength standards were adopted. The reduction of maximum load values allowed the creation of more flexible aircraft structural units. Many fittings were redesigned but the bomber retained its full specified armament, which took up part of the weight saved.

On 15 April the first aircraft was delivered for official state evaluations. It had to take part in 1st of May parade before the evaluations started. It was then that the most dangerous incident occurred, just as the plane was preparing for the parade.

The aircraft was completing its takeoff run in hands of M. L. Gallay, when a light "whoosh" was heard in the fuselage. At that moment the third engine shutdown occurred. Hydraulic pressure in the standby accumulator dropped to zero and the observer reported there was fuel stream under the tail. Gallay decided to continue takeoff because of the high speed but the plane began significant snaking after it. The rudder appeared to be moving from side to side and this resulted in the snaking. The pilot could not counteract the turns by banking to avoid wing collision with ground because of the very low altitude. When the necessary altitude had been reached the aircraft turned and began landing... When the plane was running down the runway the hot engine exhausts acted upon the spilled fuel. An explosion could occur but the engines had to operate. The wheel brakes' hydraulics were being fed from the engine pumps only because of the failure of the standby accumulator. At last the bomber stopped, having run into one of the old airframes lying around the edge of the airfield.

All the damage was quickly repaired and the M bomber was seen at the 1st of May military parade. On the 4th of May the official state evaluation programme began. It passed without serious incident. Although the aircraft had not demonstrated the necessary range, it was adopted by Soviet Air Force under designation M-4.

In service

M-4 bomber serial production was begun at Plant # 23 in 1954. The first production batch incorporated three aircraft: the two prototypes and the first production aircraft serialled 4300103. The second batch included five planes, but plant vete­ rans say the planes were built one by one. Further batches incorporated only one aircraft. It allowed various design improvements to be introduced quickly, without any production problems.

The first serial M-4 differed from the prototypes only in the lack of cartridge cases collectors under the tail turret and a different aerial layout. Production M-4s received a full avionics set but armament was reduced. Mine, torpedo and guided bomb capability was canceled. After approval these aircraft flew in accordance with the official state evaluations pro­

gramme and they were used for pilots training which was carried out at plant # 23 flight station in Zhukovsky.

Initially, new bombers had to be flown by 22nd Guards Donbass Heavy Bomber Division under guidance of General Slivka. The Division Incorpo­ rated the 101st Sevastopol Heavy Bomber Regiment and 203rd Orel Heavy Bombardment Regiment, (according to other sources there were also 121st and 230th TBAPs (Heavy Bombardment Air Regiments)). The division was based at town of Engels. Nuclear bombs had become main arma­ ment of the M-4 and thus all production aircraft were fitted with the necessary equipment. Firstly, the M-4s were equipped with the RDS-4 Tatyana 42 kt nuclear bombs. On 12 August 1953 the first Soviet thermonuclear bomb was successfully tested at the Semipalatinsk firing ground. The weapon tested was the 400 kt RDS-6s. This design proved to be flawed and another bomb was adopted. Product 37 was tested successfully at Semipalatinsk on 22 November 1955. This bomb became the main weapon in the Soviet long-range bomber inventory. Its power was equal 1,6 Mt. Later Soviet thermo­ nuclear bombs had a destructive power 3Mt and more. Furthermore, M-4 bombers could be equip­ ped with different conventional bombs.

The 22nd Division's main preoccupation was a northerly one. In case of the war the division had to reach the USA across the North Pole and to destroy targets in the Great Lakes region. Unfortunately, production M-4s had a heavier structure than that of the prototypes. Consequently their range did not exceed 8000 km with a bomb load of 5 t. Nevertheless the M-4 was considered a serious deterrent at the time. There were 33 M-4 bombers built. The bomber's production run was limited (slightly more, than 10 planes in a year) because of the insufficient capacity of Plant # 23. Furthermore, Khrushchev's rocket boom was beginning... Some M-4s subsequently taking part in different test and improvement programmes.

Each regiment in the 22nd Division had two squadrons equipped with M-4s and one squadron with Tu-16 bombers. The Tu-16s were used as trainers for M-4 crews and for weather recon­ naissance, among other tasks. Usually, each crew flew two night missions per week, the flights lasting about 10 hours. M-4 crews were reckoned to have about 1200 flight hours per year. Formation flights at extreme northerly latitudes, bombing with the assistance of a radio bombsight and other missions were performed.

The M-4 was a difficult aircraft to control and a number of design malfunctions remained. The cockpit was cramped and the heating system did not function properly: it was very cold at high altitudes. Takeoff, landing and the first turn were very hard to carry out. Designers and test pilots at the Myasishchev OKB invented various techniques and procedures to make life easier.

Amongst them were procedures for the calculation of correct elevator angle at takeoff. This was made after two crashes in 1955 when M-4s had stalled because of design peculiarities. There was a technique for a shortened takeoff run to allow delivery flights direct from Plant #23*s small airfield, thus obviating the need to transport subassemblies to Zhukhovsky for final assembly. Furthermore it enabled the bombers to use other main military air fields for emergency landings. Until then only Engels, Shaulyai, Semipalatinsk, Seryshevo and Ukrainka airbases were cleared for M-4 service.

Booster control was still unreliable. Between 1956 and 1958 seven disasters occurred in 22nd Division, all of them due to booster problems. This resulted in the temporary withdrawal of the M-4

38

from frontline service. Plant # 23 created a team of engineers to carry out these difficult improve­ ments in the field. Later all 22nd Division bases had teams of plant representatives. When M-4 bombers were again declared airworthy, pilots were trained to be prepared for booster failure. In the case of a malfunction, the pilot needed to control the aircraft with trim tabs. Some skilled fliers could adjust control so finely that the plane could fly itself without any interference. M-4 crews were highly experienced. As a rule, the crew commander had the rank of major, being a 1st class pilot, the co­ pilot normally being equally experienced.

Despite problems the M-4 continued in service. But the main drawback of insufficient range was yet to be solved. Serial production of RD-3M-500

iurbojet was begun in the mid 1950s as AM -3 turbojet improved version. The new engine had a maximum thrust of 9500 kg and at cruise of 7650 kg. Further­ more, the emergency mode of

0500kg thrust was introduced at ihe expense of the turbine's first stage nozzle inlet gas tempera­ ture increasing. But there were severe precautions: ambient tem­ perature should be no more than -15 (C, maximum flight time after emergency mode use was three nours. Emergency mode could be

.ised in case of one engine shut­ down only. Having operated at this mode the engine was remo­ ved and was sent to overhaul.

RD-3M-500 turbojets had an operational life before the first overhaul of 1000 hours and general one of 1600 hours.

The first serial aircraft (bu.

# 4300103) was fitted with new engines in 1956. It was found that the type's performance showed improvement over bombers equipped with AM-3 turbojets. However the flight range was still ess than 12000 km. During overhaul in Ryazan M-4 bombers were fitted with RD-3M-500 engines and newly built aircraft were equipped with the same.

These engines were later upgraded for longer operational life and higher adaptability in manufacture and

service. They were designated RD-3M-500A. Despite their best efforts with improved power,

the Myasishchev design bureau finally concluded that the M-4"s only chance of increasing range lay with in-flight refuelling. The drogue and cone air refueling system was proposed. The Council of Ministers issued an order to study the system on 17 August 1953. Research was led by G. I. Archangelsky. The leading designer was L S. Blinkin. Optimal refuelling plots were estimated by D. F. Orochko and the system was designed and evaluated with assistance of OKB-21, the Zvezda plant design bureau and the Lll.

When refuelling air-to-air the tanker extended its cone and had to maintain direction, speed at

Сергей Мороз

Щ Створки грузолюка ЗМ после дора­ ботки. Фото А. Андреева

ЗМ cargo bay doors after rebuilding. (A. Andreev)

about 400 km/h and an altitude of around 7000 m. The oomber approached the cone to a distance of less than 1 m and then shot the refueling probe at the с one with compressed air. If the aim was correct, the cone lock engaged the probe and refueling commenced. It was necessary to strictly maintain formation. To disengage from the tanker the M-4 decelerated and its probe separated from the cone due to tension in the refueling hose.

To evaluate the air-to-air refuelling system a modded II-28 was used as a flying lab. Furthermore two serial M-4 bombers were redesigned. The first was fitted with an air refueling probe and fuel feed pipe-lines (the a/c bu. # 5301518). The second bu # 5301619) was fitted with an additional fuel tank (3500I) and the KAZ air refueling system. It incorporated a winch with refueling hose, a pump with a fuel flow of 2250 e/min and a special razor mechanism to clip the extended hose away in case of winch failure.

Test pilots Gallay and Stepanov flew the first trials but these were not successful. Trials performed by Opadchiy were unsuccessful too. As soon as the active aircraft had taken its position aft of the cone, it began to move around. The young pilot N. I. Goryainov was the first to perform the mission in the much flown IL-28LL flying lab. He had waited for the cone to calm itself in the airflow before he engaged it. Ten successful dockings were completed on the next flight. Night trials were also undertaken. To locate the tanker, the bomber was fitted with an additional radio station and radio compass A headlight was introduced to illuminate Ihe cone, later on other lamps were also fitted. The system was named Konus (Cone) and the Soviet Air Force adopted it after its successful evaluation. A new version of the Myasishchev bomber had been prepared for serial production by that time, thus the remaining M-4 bombers only were fitted with KAZ. These aircraft were designated M-4II. (Sometimes the designation was changed to M-41 in certain documents). Tankers were able to carry a bomb load and some retained nuclear capability.

All M-4s were gradually equipped with KAZ. M-4 tankers were allocated to two squadrons as part of the 22nd TBAD. These aircraft were redesigned in the early 1960s. They were stripped of bomber equipment and part of the bomb bay was riveted closed. This resulted in a better aerodynamic performance and longer operational life than that of the M-4 bomber. Tanker squadrons were stationed at Shaulyai (Baltic region) and Serishevo (the Far East). According to Soviet military thinking in the 1970s, if necessary each airbase would receive a wing of 3M bombers to attack the USA using the Northern route and Western Europe or targets in Pacific, Japan, Taiwan or China.

Improvements

On 19 March 1952 the Central Committee of CPSU and Council of Ministers of the USSR placed an order for a new heavy bomber to be created by OKB-23 on the basis of the M plane. The order called for improved altitude and range performance. The project was designated the number 28.

This new aircraft project featured four VD-5 turbojets with thrust of 13000 kg. The layout was