Even in our time, it is not that impressive, it is stunning. Especially if you get inside. Emotions from feeling inside this huge apparatus are overwhelming simply because you understand that it could not just fly, but also with benefit. In general, delight.
Yes, nowadays, huge planes are not new. Already got used to it. But the helicopter ... Even so: Helicopter. But - in order.
It all started back in the distant 1959 year, when the interests of the national economy and the armed forces came together, who needed to transport all-in-one cargo weighing more than 20 t with the help of vertical take-off and landing aircraft and Mil Design Bureau, which did not consider the then-heavy Mi-6 to be the pinnacle of progress .
In the same years, the design of such helicopters was carried out at the largest American firms, but it didn’t go further than the preliminary design stage.
On the contrary, Mil OKB was able to present convincing arguments in the reality of building a superheavy helicopter, and on May 3 1962 was followed by a decision of the USSR Council of Ministers to develop a B-12 with a cargo cabin similar to that of a giant An-22 aircraft designed by OKB O.K. Antonov.
The helicopter was supposed to transport various types of military equipment weighing up to 25 t, including the latest strategic ballistic missiles 8K67, 8K75 and 8K82 to any, the most inaccessible parts of our country.
The project was headed by a group headed by Deputy Chief Designer N. T. Rusanovich, in 1968, it was replaced by M. N. Tishchenko. GV Remezov became the lead designer. The leading flight test engineers were D.T. Matsitsky and V.A. Izakson-Elizarov.
The majority of domestic and foreign authoritative experts believed that it was most rational to use a longitudinal scheme for a heavy-duty helicopter. To study the features of this scheme, the Flight Station of Plant No. 329 received the Army Yak-24 and the Boeing-Vertol V-44 helicopter acquired in the USA. They investigated the problems of mutual influence of screws and the distribution of power between them, determining the required power of the engines in flight modes, estimated the possibility of flight with a slip, etc. In parallel, the designers of the Design Bureau M.L. Mil created the first B-12 project, in which the longitudinal propeller-driven Mi-6 groups were located connected by a synchronizing shaft with overlapping main screws. Because of the danger of the five-lobed mainframes snagging, they were positioned with minimal overlap.
In this regard, the fuselage was quite cumbersome and longer than required for tactical and technical requirements. An analysis of the features of the longitudinal pattern showed that it leads to low values of the dynamic ceiling, speed and climb rate, the inability to continue flying with the failure of two engines and a sharp deterioration in flight performance on the dynamic ceiling and with increasing outdoor temperature, as well as a number of other undesirable consequences. Therefore, the longitudinal scheme had to be abandoned.
By the decision of M. L. Mile, the study of other schemes began. And in 1962, the OKB specialists decided to return to the idea of “doubling” the propeller-powered Mi-6 groups, but not along the longitudinal, but along the transverse scheme.
Full-scale test stand of the final version of the B-12 helicopter
In April, 1965 was followed by a Council of Ministers decree on the construction of the first experimental helicopter. The company M. L. Mile significantly strengthened the production and experimental bases, replenished the staff with new employees, and at the Saratov Aviation Plant preparations were started for the release of the first military series of five B-12 helicopters. At the end of the same year, a military customer investigated the possibility of placing 12 types of heavy military equipment on a full-scale B-36 model. In April, the State Commission finally approved the full-scale mockup for 1966, and the assembly of the first prototype began.
At the beginning of the summer of 1967, the first flight model was declared ready for flight testing.
The B-12 was a four-engine transport-paratrooper twin-screw transverse scheme. The motor groups from the Mi-6 were mounted on the ends of the truss consoles. The diameter of the finished rotors was insufficient for this helicopter, which required forcing the initial power units.
In the design bureau P. A. Solov'eva, a special modification of the D-12F serial engine, hp 25, was created for B-6500. Wings with a narrowing of less than one had a small transverse V angle to improve the helicopter's flight characteristics. An intermediate gearbox was installed in the center section, providing a break in the transmission shaft. The transmission shaft synchronized the rotation of the three-meter overlapping main rotors and transferred power from one gearbox to another with roll control and in case of failure of one or even two engines on one side. Fuel was placed in the wing and outer outboard fuel tanks.
The fuselage of the B-12 was made in the shape of a semi-monocoque and resembled inside, in the figurative expression of one of the foreign experts, like a giant Gothic cathedral. Its front part was occupied by a double deck cabin. On the ground floor there were two pilots, a flight engineer and a borter electrician, on the top floor there was a navigator and a radio operator.
Cargo bay, view from the entrance to the cockpit
General plan of the first floor of the cockpit
Places of the first and second pilots
Airborne workplace
Flight engineer seat
Second floor - Astrootsek
Workplace navigator
Radioman's place
Supernovae for the 60s of the last century. This is a vertical viewing camera for landing in poorly lit areas.
Passenger seats. For example, for accompanying persons
In the rear part of the fuselage, there was a power ramp and side flaps, which, when opened, formed an opening for the entry of self-propelled equipment and loading various loads with the help of powerful electric winchs and hoists. The central part of the fuselage was occupied by a large cargo compartment measuring 28,15 x 4,4 x 4,4 m. It could accommodate 196 soldiers or 158 wounded.
The helicopter was equipped with modern flight-navigation systems, allowing to perform flights in adverse weather conditions. Significantly simplify the piloting of the B-12 should have been a four-channel autopilot and an automatic support system for a given rotor speed.
27 June 1967. Test pilot V.P. Koloshenko for the first time raised B-12 into the air from the factory site in Panki.
From December 1967, systematic elevations of B-12 began. He made a flight from the factory site to the flight test station cost centers. The entire program of factory tests was completed in a month without complications, which was largely due to very good theoretical preparation and experimental testing of the entire project. The dynamic system did not need to be refined, since when creating the B-12, units of the power plant and carrier system from the Mi-6 helicopter were used in operation.
In the autumn of 1968, the first stage of joint state tests began at the Flight Research Institute. They passed safely in strict accordance with the program. The modifications concerned mainly the equipment of the helicopter.
In addition to the specially designed autopilot AP-44, an experienced autopilot VUAP-2 was installed, which was later replaced by the AP-34B1, radar station Lotsia, suspended fuel tanks, etc.
In addition, instead of the all-metal blades from the Mi-12, new blades of a composite structure were tested on B-6 (steel spar with fiberglass bow and tip with foil honeycomb core).
22 February 1969. During state tests, the crew of V.P. Koloshenko set an absolute world record of carrying capacity, lifting 31 cargo to the height of 2350 m, and 6 of August of the same year recorded a new outstanding achievement of the Soviet helicopter industry: crew V.P. Koloshenko on B-12 lifted 40,2 cargo to the height of 2250 m.
This record has not been closed so far, and it is unlikely that in the coming decades there will be a rotorcraft capable of competing with the giant created by the Mil Design Bureau M. Mil.
In total, seven world records were set on the B-12. For the creation of the heavy helicopter B-12, the Design Bureau M. L. Mile was awarded for the second time the Prize of I. I. Sikorsky, awarded by the American Helicopter Society for outstanding achievements in helicopter technology.
B-12 successfully passed all the planned factory tests, performed 122 flight and 77 hangings, during which the calculated flight data and the reliability of the systems were fully confirmed.
The helicopter showed good flight characteristics both with the autopilot turned on and off, high handling characteristics in the autorotation mode, low vibration and noise levels, and comfort of the pilot cabin.
The helicopter demonstrated the ability to continue flying in the event of the failure of two engines, the possibility of a significant increase in payload during take-off.
Despite the fact that compared to its predecessor, the B-12 cargo compartment volume increased by 7,2 times, its specific weight characteristics turned out to be at the level of Mi-6 indicators. Long-haul flight Moscow-Akhtubinsk-Moscow in 1970 ended the first stage of the joint state tests B-12.
At the end of October 1970, the State Commission recommended launching it into mass production.
In May-June 1971, the B-12 was successfully demonstrated at the 29th International Salon aviation and astronautics in Le Bourget, where he was recognized as the "star of the salon." Then followed demonstration flights in Paris, Copenhagen and Berlin.
"Before the engineering achievement, which is the Mi-12 helicopter, you can take off your hat," said the son of the great founder of the serial helicopter industry, I. I. Sikorsky, Sergei Sikorsky, vice president of Sikorsky Corporation. - The development of technology teaches us that in its assessment it is impossible to use a superlative degree. The Mi-12 helicopter is one of the exceptions that prove the rule. We are talking about a helicopter in superlatives ... "
Unfortunately, despite the successful completion of the first stage of state trials and the “Parisian triumph”, the B-12 debugging was delayed. Assembled in 1972 on the pilot production cost center, the second copy of the B-12 stood for a year in the workshop awaiting engines.
Only 28 March 1973, he made the first ascent into the air, and the next day he was overtaken to the flight station to continue state tests. The second copy was different from the first, which took place at this time bulkhead and fault detection, more rigid controls and reinforced tail pillars.
The crew of the second helicopter was headed by test pilot GV Alferov. The doubler flew successfully, but the customer unexpectedly refused to accept the B-12 to the second stage (phase “B”) of state tests.
In 1974, all the work on fine-tuning two experimental machines was stopped. The first copy of the B-12 remained at the "perpetual storage" at the plant, and the second was transferred to the Air Force Museum in Monino.
There were several reasons for this. The main thing was that the task for which B-12 was created, the provision of mobile basing of strategic ballistic missiles, had lost relevance by the end of 60's. The customer has changed the concept of missile deployment.
Some types of missile systems for which B-12 was developed were unsuccessful and were decommissioned (for the same reason, the large An-22 series planned for production was sharply reduced).
Other similar types of military goods did not need so urgently in such an expensive means of delivery as a helicopter. In addition, the Saratov plant, which was preparing to manufacture B-12, at the time of the decision to launch the giant into the series turned out to be tightly loaded with the manufacture of another type of product. And to top it all, under the circumstances, the OKB was not interested in introducing the B-12, as this could prevent the development of a new promising heavy helicopter of the third generation, the Mi-26, which is slightly inferior to the twin-screw giant in terms of capacity, but -economic indicators.
To say that the work was done in vain, it is impossible. The development of B-12 allowed, at a minimum, to prove the feasibility of using the method of doubling screw-motor groups to increase the capacity of rotary-wing aircraft.
Flight technical characteristics of the helicopter В-12:
Dimensions:
main rotor diameter - 35 m
length - 37 m, width - 34
height - 12,5 m
Helicopter weight:
empty - 69 100 kg
normal takeoff - 97 000 kg
maximum take-off - 105 000 kg
The power plant - 4 GTE D-25VF power 6500 hp / 4847 kW.
The maximum speed of the helicopter is 260 km / h, cruising - 240 km / h.
Practical ceiling - 3 500 m.
Practical range - 500 km, distillation - 1000 km.
Crew car - 6 people.
Passenger capacity - 196 people.
The normal payload is 20 000 kg of cargo, the maximum load is up to 25 000 kg.
Source:
Mikheev, V. R. Moscow Mil Moscow Helicopter Plant. 50 years.