As the creator of combat gyroplanes, Nikolai Kamov became the main supplier of rotary-wing aircraft for the ships of the Soviet fleet
Predecessor and successor: Ka-15 against the background of the Ka-25PL. Photo from the site
The first experience of using Ka-10 coaxial deck helicopters, developed by Nikolai Kamov's OKB-2, convinced the fleet that it needed such machines. But a rotary-wing aircraft with a crew of one person and a small payload could only perform the functions of a liaison, and in some situations - a reconnaissance. A vehicle of greater carrying capacity was required, which would become one of the elements of the anti-submarine defense system, and could also serve as a rescuer, reconnaissance officer, and so on. In a word, the fleet needed a universal deck helicopter, and, in the opinion of the naval command, only Kamov could give it.
The sailors' logic is not difficult to understand. Mil OKB, although it worked very actively, was engaged in single-rotor machines, which were distinguished by their large dimensions. Whether you want it or not, such helicopters need a tail boom, which means that more space for its landing and storage is also needed. And the Kamov coaxial machines were significantly smaller: their limiting dimensions were actually determined by the diameter of the main rotor, and it was, by definition, less than the diameter of the same propeller of single-rotor machines.
In addition, Mikhail Mil was attacked by the army, which demanded rotary-wing aircraft for themselves. And the fleet, accustomed to the fact that its orders, if they overlap with the army, are carried out on a leftover principle, could not count on the speedy fulfillment of their helicopter orders. And the newly formed - and just at the insistence of the fleet! - Kamov design bureau was not engaged in any other machines. And I was not going to study. Because General Designer Nikolai Kamov made his main stake on machines with a coaxial design.
Coaxial ridge of Nikolai Kamov
Why did Nikolai Kamov, who quite successfully worked on the creation of gyroplanes and after the war, created the project of a single-rotor helicopter "YurKa", in the end made a bet on coaxial machines? There is no unequivocal answer to this question and cannot be: only the general designer himself could give it, but not a word is said about this in his manuscript "The Creation of the First Soviet Helicopter". Most likely, a set of reasons led to the final choice of Kamov's scheme, which can be described in more detail.
Ka-15, during state tests, lands on the deck of the ship. Photo from the site
On the one hand, there was a purely hardware reason: Nikolai Kamov needed a helicopter theme that would put him on an equal footing with the former deputy for the plant at Ukhtomskaya, and by that time the quite successful and influential aircraft designer Mikhail Mily. By the end of the 1940s, he had already brought his first serial Mi-1 helicopter to state tests, and it was clear that it would not be possible to overtake him in the field of single-rotor machines. And working with coaxial helicopters was the very opportunity to find a niche in which Kamov had no competitors.
On the other hand, the coaxial scheme, despite its rarity, has a number of significant advantages over a single-rotor one. Yes, it is more difficult and more dangerous from the point of view that the lower screw is located in the area of the upper airflow. Yes, the builders of such helicopters have to decide what to do with the main threat - the overlap of the ends of the blades of the upper and lower propellers. Yes, such helicopters have increased drag and a noticeably higher height than single-rotor helicopters. But on the other hand, they are at least 15% more efficient, since the engine power is not taken away to control the tail rotor. They are much more compact: the same Ka-15 was twice as short as the Mi-1, due to the absence of a tail boom. They have no cross-links in control: the first serial Kamov Ka-8 helicopter was much easier to control than the same Mi-1. Coaxial helicopters have the best maneuverability, since they do not need any controls other than coaxial propellers - and no time is wasted on their engagement and response. So when flying in tight airspace, with many obstacles, with a deck trying to slip out from under the landing gear, coaxial helicopters have no competitors.
And thirdly, as far as one can guess, it was important for Nikolai Kamov, like any inventor with a generous talent, to find his way in aircraft construction and say his own truly new word. In the field of single-rotor helicopters
scheme he had no such chance. But to return to the origins - it is enough to recall the first helicopter by Igor Sikorsky, built according to a coaxial scheme - it made sense. And it is Kamov who owns, in particular, the copyright certificate for an invention called "Helicopter rotor", which eventually entered into wide practice under the name "column of coaxial propellers". And in total, there are dozens of such testimonies received by the general designer of OKB-2 personally or in collaboration with colleagues - and almost all of them relate to the coaxial scheme.
The Ka-15 civilian four-seater modification - the Ka-18 helicopter - in civilian livery at the airfield of the Flight Test Complex in Zhukovsky. Photo from the site
Perhaps there were some other, purely personal or smaller reasons that ultimately led Nikolai Kamov to choose a coaxial scheme as the ridge of his design bureau. As the famous aerodynamic scientist Leonid Wildgrube joked, one of those scientists who made a colossal contribution to the development of the Soviet school of helicopter aerodynamics, "the coaxial scheme owes all its shortcomings to Nikolai Kamov." Indeed, no one in the world has studied the mechanics and design of the coaxial scheme so deeply and closely, and no one has built such a number of successful coaxial helicopters.
The Ka-15 was designed to be very compact
But back to the history of the creation of the Ka-15. After the order of the fleet for the development of this helicopter was received, the preliminary design and the tactical and technical assignment of the customer were agreed, work on the direct design of the machine was launched at OKB-2. One of Nikolai Kamov's closest associates, Vladimir Barshevsky, described in detail how they passed in his memoirs, in his book "A View from the Inside of the KB". In particular, he describes the situation in which Kamov's design bureau began work on the first large-scale deck helicopter of the Soviet Navy:
“At the beginning of October 1951 N. I. Kamov was summoned to the Kremlin. Three hours later, he returned very upset and said that besides him, A. N. Tupolev, S. K. Ilyushin, N. N. Bratukhin and M. L. Miles. The task of urgent creation of transport helicopters was discussed. Mil reported on the project for a twelve-seat Mi-4, and Kamov - on the Ka-14-2 project (a heavy longitudinal transport and landing helicopter capable of lifting 30-40 infantrymen in full gear. - Author's note). The production time for the machines was set at one year. Nikolai Ilyich objected that he needed at least two years. L. P. Beria was very dissatisfied with his answer. The next day, only M. L. Mile and … A. S. Yakovlev and persuaded them to take on the task, promising unlimited help. Already on October 5, a government decree was issued on the creation of single-rotor and longitudinal transport helicopters for 12 and 24 people, respectively. Mil OKB was transferred to plant number 3, Bratukhin's OKB was disbanded, and OKB-2 was transferred to Tushino, where Mil was previously based. Thus, our project was actually transferred to Yakovlev.
The Mi-4 helicopter began spinning the main rotor in April 1952, in May 1953 the state tests were completed, and at the end of the year the first production aircraft were produced in Saratov. Yak-24 made its first flight on July 3, 1952. At the beginning of 1953 it was transferred for state tests, only in April 1955 it completed them and in August it was shown at the parade in Tushino. Kamov was right: you cannot make such a car in a year, but it is dangerous to disagree with the high authorities.
In the meantime, we were again moving to an uncomfortable base, where it was necessary to build the Ka-10 military series and develop the Ka-15 by order of the Ministry of Aviation Industry No. 1040 dated October 23, 1951.
Helicopter Ka-15 on the helipad of the legendary icebreaker "Ermak" during tests in Murmansk. Photo from the site
This move, which demonstrated the dissatisfaction of the "top" with the obstinacy and excessive independence of Kamov, was another blow of fate, which the designer and his subordinates survived with their inherent resilience. Work on the creation of the Ka-15 continued, and soon the machine began to take on more and more complete outlines. Vladimir Barshevsky recalls:
“The Ka-15 helicopter intended for ships was designed very compact. Its length was almost half that of the Mi-1. It is not easy to place in a small volume all the equipment needed to search for submarines. We were looking for the optimal layout of the helicopter with engineers V. I. Biryulin and B. Yu. Kostin, since the Chief Designer was at the state tests of the Ka-10 in Riga. Nikolai Ilyich Kamov, returning, looked through a dozen of the options we had invented, immediately chose the simplest and, in our opinion, the worst. It was the familiar wheeled chassis layout. According to him, firstly, with the float landing gear, we have already had time to work hard on the Ka-8 and Ka-10, but wheels are still needed to move on the ground; secondly, landing on the ground on floats from the autorotation mode is an almost inevitable presence of a hood and, thirdly, even the Ka-10 during takeoff and landing was insured by specially trained people, otherwise the machine could enter into “earth resonance”, because damping in the cylinders was insufficient."
And so it happened that the first serial deck-based multipurpose helicopter of the Soviet Navy - and the first multipurpose civilian helicopter of the coaxial scheme - acquired conventional landing gear rather than floats. However, later, while working on the Ka-15M, this car was put on floats in one of the variants, but this modification did not become the main one.
Ka-15 on floats while boarding the ship. The machine is marked "Aeroflot", but at the same time it is equipped with a submersible sonar station with a winch on the left side, that is, it is an anti-submarine modification. Photo from the site
Who lifted the tag into the air
Almost two years were spent by Nikolai Kamov and the employees of his design bureau, as well as the workers of the experimental enterprise, to bring the new machine to embodiment, so to speak, in metal - and wood, since the design of the blades of both propellers was wood-metal. On April 14, 1953, the first prototype of the Ka-15 helicopter, intended for life tests, took off. In his cockpit sat test pilot of the Kamov design bureau Dmitry Efremov.
This man played such a big role in the fate of the first serial helicopters of Nikolai Kamov that he is worthy of a detailed story. A Muscovite, he began his journey to the skies at the Bauman Aero Club in 1941 and immediately after the outbreak of the war was sent to study at the Saratov Military Aviation Glider School. Since 1943, Efremov fought as part of the training air-glider regiment of the Airborne Forces, delivering ammunition, weapons and reconnaissance and sabotage groups on heavy gliders. After the war, he remained to serve as a pilot in the airborne units, but in 1948 he was demobilized due to tuberculosis. It was not easy to find a job at that time of the mass demobilization of soldiers and officers who had won their own, but Dmitry Efremov was lucky to get a job practically in his specialty: he began working as a mechanic at Nikolai Kamov's design bureau.
As the general designer later recalled, Dmitry Efremov learned to fly helicopters under the guidance of chief pilot Mikhail Gurov, one of the closest associates of Nikolai Kamov and a pilot who stood at the origins of the design bureau. At first, the mechanic, who had already grown to become a minder, began to trust the "hovering" in the experimental Ka-10 machine on a retaining cable. Then he got the opportunity to control the helicopter, which moved back and forth along two cables fixed at the ends on the ground - this was the so-called "trelle" simulator invented by Gurov.
Test pilot Dmitry Efremov controls the Ka-10 helicopter, the third prototype. Photo from the site
As a result, in September 1949, Kamov, who noticed the persistent minder-pilot, appointed him a test pilot by his order - and he made the right decision. He recalled the people who knew Dmitry Efremov, he was a real test pilot, that is, not only a pilot, but also an engineer and a designer who created a method for balancing the coaxial rotor scheme. All the first large-scale OKB-2 helicopters, from the Ka-15 to the Ka-25, passed through his hands. Unfortunately, Efremov became the chief pilot of the Kamov "firm" under tragic circumstances. On October 8, 1949, Mikhail Gurov died during the next test flight on the Ka-10, and since there were few test pilots in the design bureau, Efremov was instructed to fly over Ka-10 No. 3.
Dmitry Efremov quickly proved himself to be an attentive pilot, able not only to notice everything that happens to the car, but also to assess the reasons for such behavior. It is enough to give just one example. In April 1949, Efremov was tasked with preparing a Ka-8 helicopter for training hovering on a leash. During the approach, due to unreliable locking of the ball joint nut, the thrust connecting the lead of the upper blade with the swashplate was disconnected, and the blades were skewed. So, in an explanatory note on the fact of the accident, the pilot simply described what he felt and did, and also quite accurately recreated the details of the emergency, describing in detail that the vanes converged in the right hemisphere, and why, in his opinion, it happened.
Thus, the former military glider pilot showed the most important qualities of a tester: a good reaction and the ability to see and remember the essential moments of an emergency situation. And also the ability to calmly do everything to avoid a catastrophe - if it is possible in principle. Alas, once it turned out to be completely impossible: Dmitry Efremov, chief pilot of OKB-2 Nikolai Kamov, died on August 28, 1962 during the disaster of the Ka-22 rotorcraft, which happened during the transfer of the car from Tashkent to Moscow as part of acceptance tests.
But then, on April 14, 1953, everything was still ahead: the development of the Ka-15 to state tests, and new machines, and the last flight in life. Now the main thing was different: to teach how to fly a new rotorcraft, which was so awaited in the Navy.
A Ka-15 helicopter on the deck of a fishing vessel, where such machines were used as reconnaissance agents for a game. Photo from the site
Price for the right to be first
The process of fine-tuning the Ka-15 was very difficult. As Nikolai Kamov's OKB specialists later admitted, many of the dangerous phenomena accompanying the coaxial scheme, which was poorly studied at that time, simply did not appear at the G8 and Ten due to their relatively small size. But on the "tag" with all of them had to literally fight, bearing not at all figurative losses.
Combat Ka-15 of the Black Sea Fleet at one of the Crimean airfields. Photo from the site
First of all, it was necessary to deal with all kinds of vibrations that literally pursued these machines. First, we dealt with the vibrations of the rotor and the column of coaxial propellers. Then, the reasons for the vibrations of the helicopter itself, both longitudinal and "ground resonance" (associated vibrations of the blades and the fuselage, arising, as a rule, on the ground), were found out and eliminated. Then I had to spend a lot of energy - and, alas, human lives - on eliminating the causes of the overlap of the blades, which is almost inevitable for coaxial helicopters … accumulated a lot.
Nevertheless, in May 1955, the state tests of the new vehicle, which took less than a month, were completed quite successfully, and the military tests, which were carried out on single and group-based cruisers, soon came to an end. On the cruiser "Mikhail Kutuzov", in particular, comparative tests of the Mi-1 and Ka-15 helicopters were carried out. The main conclusion was obvious: the long tail boom of the Mi-1 practically excludes the possibility of using this helicopter on a ship when rolling.
The serial Ka-15 helicopter was put into production at the Ulan-Uda Aviation Plant in April 1956. And in March next year, new vehicles began to arrive in combat units. Unfortunately, they did not last long: due to the entire complex of "childhood diseases" of the Ka-15, several major accidents occurred with the participation of this machine, and in May 1963, the flights of these helicopters in the Navy were banned. After that, the remaining helicopters were gradually transferred to civil aviation, where the Ka-15 continued to fly until the second half of the 1970s.
After being fired from the Navy, the Ka-15s were actively used in the Soviet DOSAAF. Photo from the site
Despite the relatively short service life of these helicopters, their creation and operating experience served as an excellent basis for the development and implementation of other rotary-wing aircraft from the Nikolai Kamov Design Bureau in the fleet. After all, as noted by the participants in the state tests, as a result, the flight performance characteristics of the "tag" turned out to be higher than the design ones. The vehicle carried a commercial cargo of 210 kg with a take-off weight of 1410 kg and an engine power of 280 hp. (The Mi-1 took 255 kg with a weight of 2470 kg and a power of 575 hp), and the handling characteristics inherent in a coaxial helicopter and the compactness of the machine made it possible to perform takeoffs and landings from very limited areas. This is what allowed the Ka-15, and then the modifications of the Ka-15M and Ka-18 that appeared (a purely civilian four-seater modification of the helicopter, capable of performing, among other things, the functions of an ambulance) to remain in service in the civilian fleet for two decades.
The Ka-18 differed from the Ka-15 in its large cockpit size, which was even adapted to accommodate medical stretchers. Photo from the site
During this time, they managed to prove themselves everywhere: in army exercises, and in polar expeditions, and in whaling fleets, and as an agricultural one. In the fleet, the Ka-15 also performed many tasks: it was an anti-submarine helicopter (since the carrying capacity of the "tag" did not allow to equip it with both detection and destruction means, they were used in groups of three vehicles, each of which carried its own part of an ASW), auditioned for the role target designator for the KSShch anti-ship cruise missile complex, acted as an observer and a communications helicopter. In total, 375 Ka-15 helicopters were produced, including prototypes, which made it the first large-scale helicopter in the history of the Nikolai Kamov Design Bureau - and the first large-scale carrier-based helicopter in the Soviet Navy.
The performance characteristics of the Ka-15 helicopter
Fuselage length - 6, 26 m
Main rotor diameter - 9, 96 m
Fuselage width - 2.85 m
Height - 3.35 m
Engine - 1 AI-14V, piston, air-cooled
Power, kW - 1 x 188
Maximum speed -155 km / h
Cruising speed - 120 km / h
Ferry range - 520 km
Practical range - 278 km
Service ceiling - 3500 m
Static ceiling - 600 m
Empty weight - 968 kg
Takeoff weight - 1370 kg
Maximum takeoff weight -1460 kg
Payload mass - 300-364 kg
Flight duration - 2.5 hours
