NASA Ames Research Center conducted wind tunnel tests on the K-16B.
The sole Kaman K-16B is resting in the New England Air Museum, Hartford, Connecticut.
Kaman K-16B tilt-wing STOL research aircraft
Engines: 2 x GE T-58-2A, 1024 hp Wing span: 34 ft Length: 38 ft 4 in Height: 19 ft 3 in Normal gross: 9295 lb Design max speed SL: 211 kt Deign max speed 15,000ft: 215 kt Max ROC: 6000 fpm Vertical climb: 400 fpm Service ceiling: 36,000 ft Hover ceiling: 2400 ft Range w/1000lb fuel: 205 nm Max range speed: 130 kt TO to 50 ft 12,000 lb: 514 ft Mean aerodynamic chord flap extended: 112.1 in Prop Airfoil: NACA 16-500 Prop diameter: 14 ft 10 in Prop blade chord: 18 in Flapping hinge radius: 9.2% Blade pitch range: 15-45 deg Max wing tilt: 50 deg Wing flap deflection: 60 deg Rotor blade flap collective: 13 deg max Rotor blade flap cyclic: +/- 25 deg
Formed in 1945 by Charles H. Kaman as Kaman Aircraft Corporation to develop a special servo-flap control system for helicopter rotors and “synchropter” lntermeshing twin rotor system, with aim of eliminating anti-torque tail rotor. K-125A built in 1947; K-190 in 1948; K-225 built in small numbers as YH-22 from 1949. HOK-1 delivered in quantity to U.S. Navy and Marines during 1950s; HTK-1 to Navy as trainer/ambulance, and also adopted as remote-controlled drone. By late 1960s well over 200 H-43 Huskie turbine-powered rescue helicopters were serving with the USAF. H-2 Seasprite naval rescue and utility helicopter first flown July 1959, retaining servo-flap system, though on a conventional main rotor. Seasprite developed in many versions, early production models using a single turboshaft engine and later models with twin turboshafts; experiments included stub wings serving as sponsons and gunship version with Minigun chin turret among other weapons. In the late 1960s much subcontracting undertaken, together with development of Rotorchute and allied devices. Became Kaman Group in 1965 with extended activities, with Aerospace subsidiary subsequently taking the present name Kaman Aerospace Corporation as part of Kaman Group. Current programs include producing upgraded SH-2Fs as SH-2G Super Seasprites for antisubmarine/ anti-shipping, over-the-horizon targeting, SAR, mine countermeasures, vertrep and other roles, for delivery to Royal Australian Navy, Royal New Zealand Navy, Egypt, and U.S. Navy Reserve; production of K-MAX “Aerial Truck” single-seat, turboshaft-powered and twin intermeshing rotor external-lift helicopter (first flown December 1991); and subcontract work on Boeing airliners and for various military aircraft including AH-1, C-17, Comanche, F-22, and V-22.
1995: Old Windsor Rd, PO Box 2, Bloomfield, Conneticut 06002, USA. In 2000 Kaman Aerospace was se¬lected by MD Helicopters (MDHI) to be the sole supplier of fuselages for its line of single-engine helicop¬ters, including the MD600N, MD520N, MD530F and the MD500E. The agreement is worth a reported $100 million.
One of the more original KA Kalinin designs was the experimental K-12 or VS-2 (Russian: Калинин К-12 (ВС-2)) tailless aircraft, which had its origins in a request made on July 4, 1932 by the VVS RKKA to the Kharkov Experimental and Serial Aeronautical Construction Factory (JAZOSS) within the framework of the process of modernization which began in February.
It was necessary to replace the Polikarpov R-5. The technical requirements for the new model were dictated by the NII VVS as a multifunctional aircraft for military purposes under the name VS-2, an acronym for V oickovoi Samoliot -2 or Military Aircraft -2.
The K-12 was designed as a light bomber, reconnaissance aircraft, photographic reconnaissance and even light transport aircraft and ambulance. The required speed had to exceed 250 km/h at an altitude of 3,000 meters and the radius of action was 350 km.
By April 1933, the first conceptual drawings of the model were delivered in three versions with the use of three power plants: M-22, M-49 and M-52.
These versions included a traditionally designed aircraft, a twin tailcone structure aircraft, and a third that was close in outline to a flying wing, but featured a small-area horizontal tail surface, located close to the fuselage, thus which was known as the “short tail version”.
Kalinin convinced the head of the NII VVS VK Lavrov to choose the last variant. In his opinion, this variant should have the greatest maneuverability and the best defensive composition due to the absence of firing dead zones. The works began with the tests of some models in the wind tunnel of the Kharkiv Aviation Institute.
After an initial analysis at the NII VVS, the VS-2 project was not approved. It was argued that the project was incomplete and the aircraft overloaded. The use of the M-52 engine according to the data provided by the TsAGI would not be included in the experimental construction plan and the rupture of the crankcase during the tests required important modifications, so it was not feasible to project any aircraft on the basis of that power plant.
The only interesting thing according to the VVS leadership was the flying wing scheme. At that time, both in the USSR and abroad, this scheme attracted aircraft manufacturers, but only the most daring faced it. Too many technical aspects had to be taken into account and, despite the fact that the calculations showed that such a configuration would bring important advantages in terms of speed, manoeuvrability and defensive ease, the risk was too great.
In September 1933 JAZOSS submitted a second VS-2 variant for study. By then the project had already received the K-12 index in the KB. This project was also close to the concept of a flying wing, but kept the tail unit. The engines were located on the sides of the fuselage, inserted into the leading edge of the cantilever wings. The wings had a rectangular shape in the center plane, with trapezoidal consoles with arrows on the leading edge and the trailing edge straight, following the line of the center plane.
Single spar stabilizers were attached to either side of the fuselage, just aft of the wing trailing edge. To reduce the landing speed, Northrop – type surfaces were placed along the entire length of the wingspan. The wing leading edge featured two section slats, the outer ones featured automatic operation and the inner ones were pilot controlled. Aerodynamic surfaces were also located on the surface of the intrados, which were extended during landing, increasing the wing surface by 15-20%.
This version would lead to the definitive variant without a tail and with trapezoidal wing consoles, with vertical surfaces used as rudders located at the ends.
The civil version of the model was calculated for 11 passengers and a postal variant accommodated six. The plane could be disassembled to be transported in rail cars.
The novelty and complexity of the project forced a detailed analysis of the data presented. At that time in the USSR there was no experience in similar configurations or theoretical bases that would allow comparing the calculations presented. For these reasons, the analysis of the TsAGI and a group of renowned specialists who had to study the material presented were requested.
During the analysis of this proposal, a series of criteria were issued, which prevented an effective assessment of the calculations presented. The selection of the model geometry was considered to lack a theoretical basis. The selection of the shape and surface of the empennages and the aerodynamic characteristics of the machined surfaces of the wing had not been calculated. The static coefficients were not presented with the project, nor were wind tunnel tests carried out to confirm the correct selection of this composition. On the other hand, the performance calculations were presented without a specific definition of the propeller to be used, so it is impossible to verify them.
Problems were found in the calculation of the balance and weight of the aircraft, its payload capacity, fuel and oil and many other aspects, so it was considered that the results of the calculations presented did not correspond to reality. It was pointed out that the aerodynamic calculations for the M-22 and M-52 engines had been made on the basis of the same weight, which was not true.
As a result of the analysis, the report considered that the conceptual project presented by the JAZOSS with two M-22 engines was prospective for both military and civilian use, for which reason it was concluded that it could be approved in general, excluding the dimensions and position of the empennages and ailerons, which still needed to be tested in the wind tunnel. The installation of the M-22 engines in the VS-2 was considered temporary, until the M-52 engines were ready. The presentation of a landing gear on skis was also established as a condition for the state tests.
Another report, presented on October 29, 1933, clearly highlighted that this new project had too many little-studied aspects such as its general configuration, the wing without tail, the Northrop planes and the slats. There were no clear calculations of their independent behavior and even less of their work together. It was also written that according to the opinion of the specialists the new scheme would not bring any gain from the aerodynamic point of view. Answering concerns about stability and landing would still require a lot of testing in the wind tunnel. For all these reasons it was proposed to build only a model on a smaller scale with purely experimental objectives.
Lastly, the report presented by Ilyushin considered that the military scheme of the model should not be approved. It was still necessary to work with the loads, meet the requested technical requirements and demonstrate the feasibility of the installation selected for the flight control bodies.
The Kalinin K-12 was conceived as a tailless aircraft in a flying wing configuration with wingtip empennages of mixed construction.
The oval section fuselage featured three sections that were bolted together. The structure was conceived of welded steel tubes covered in fabric. The navigator and gunner positions in the tail featured steel and duralumin cladding.
The midplane featured two spars made of chrome-molybdenum alloy steel tubes. The wing nerves were made of 10 х 8.5 mm steel tubes. The forward region of the midplane, between the leading edge and the spar and the rear, from the spar to the trailing edge, were constructed of duralumin and stainless steel. The central area, near the engines and the fuselage, were covered with fabric.
The wing consoles, with R-11 profile and trapezoidal shape, also had a double spar structure made of wood. The covering was plywood. The vertical and horizontal tail surfaces were made of fabric-coated steel tubes. The three-section ailerons were located along the entire length of the wingspan. The central section was used as elevons.
The power nacelles occupied the entire wing chord on the intrados and served as shelter for the main landers. The main landers on the prototype were fixed and used low-pressure wheels to allow them to operate over unprepared runways. These landers lacked depreciation. In winter operations the train had to be replaced by one of skis with hydraulic amortization.
The K-12 was powered by two M-22 engines produced at Factory No.19 with 2.8 meter diameter metal propellers. The starting of the engines was carried out by means of compressed air or with an external starting system. The use of Townend rings allowed proper cooling of the engines. During the tests, no abnormal heating was observed in the cylinder heads. The use of this hood, which could be easily removed, made it possible to facilitate technical intervention actions.
The fuel system consisted of 4 tanks located symmetrically in the wing, with a total capacity of 900 kg. The oil capacity was 90 kg.
The Kalinin K-12 was designed for a crew of three. The pilot was located in the high cabin located in the central area of the fuselage. In the nose was the gunner navigator with a turret armed with machine guns. The navigator’s cabin had double control and at least conceptually it should allow flight operation, despite the fact that in practice the instrumentation there was very poor. At the end of the tail section was located a defensive turret operated by the gunner. The cockpit and fuel tanks could be covered with removable armor.
Kalinin K-12 cockpit
The aircraft in its bomber configuration was capable of carrying 500 kg of bombs inside the fuselage. Defensive armament consisted of two 7.62mm ShKAS machine guns operated by the navigator and tail gunner.
In order to check the theoretical calculations, Kalinin decided to build, in addition to the scale models for the aerodynamic tests, a 1:2 scale glider of the VS-2. This 9 meter wingspan glider was built in Kharkiv in 1934 and air tested by pilot VO Borisov.
Construction of the scale glider
The first flight presented problems. After the glider broke free from the tug the pilot was unable to control the model and the glider inverted. The pilot launched (or was launched) from the glider, which once lightened, hovered smoothly and landed on the back. After the repairs, the causes of the problem were established and a new test was carried out, which this time passed without problems. The pilot VO Borisov successfully carried out about 100 flights, aimed at checking the real behavior in different flight regimes.
The builder AV Kovalienko next to the scale glider built in 1934
The transfer the new location in Voronezh also added to development delays. Only at the beginning of 1936 was the construction workshop able to begin work on the full-size aircraft.
In June 1936 the K-12 plane left the workshops for the factory test airfield and a month later the test pilot VO Borisov made the first flight. The factory tests requested were carried out without difficulties. This aircraft in the colors of the “Fire Bird” (Zhar Ptitsa) took part in the festivities for the day of the Soviet Air Forces on August 18, 1937 over Tushino. At that time, the state tests began at the NII VVS.
Kalinin K-12 during state testing
Third rank military engineer Samarin was selected as the person responsible for the tests. Borisov was chosen as the pilot by the factory. The engineer Nersisyan, the captain Shaurov and the technician Androsov also participated. The main objective of the tests was to define the flight properties of the VS-2 2M-22 aircraft and its performance, as well as to study the characteristics of the flying wing system in relation to its stability and flight control.
At the end of 1936 the aircraft was flown by PM Stefanovski , who issued a completely negative assessment of the model. The particular characteristics of the configuration brought as a consequence that the pilots during the tests were conducted with suspicion and it was considered that the VS-2 was a dangerous device. This played a not insignificant role in the future of the model.
The VS-2 2M-22 accumulated 62 flights with a total of 33 flight hours, including 12 hours in 16 flights made at the NII VVS. In them it was shown that the model was stable in flight and responded favorably to the controls. Stability problems were noted during single-engine flights and during takeoff and landing operations due to ineffective wingtip empennages. Big problems were observed due to the lack of retracting of the landing gear. The tests could not be fully developed.
Problems prevented flights with overloads, combat manoeuvres, weapons tests, dynamic stability, and manoeuvrability.
In the conclusions it was noted that the VS-2 2M-22 aircraft with a flying wing scheme was considered purely experimental. For this reason, the objective of the tests had been directed to the definition of its stability and control properties of tailless aircraft, which at that time were considered the main questions in relation to this configuration.
The data obtained in the flights were not considered sufficient to be able to answer the questions, but they did give the possibility of obtaining some fundamental conclusions for the future development of aircraft in this configuration.
The VS-2 2M-22 aircraft showed good flight conditions. Horizontal flight could be maintained at speeds of 120 – 200 km/h and in this range stability was acceptable. The plane could glide at speeds between 115 and 120 km/h. It took off easily after a not very long run and at a fairly low speed, over 100 km/h. The takeoff trajectory had a tendency to be carried out in a circle. The landing speed was also low, close to 77 km/h. The airplane was considered statically stable under conditions of center of gravity location at 27% of length with rudders locked. With free rudders the plane was not stable.
The effectiveness of the vertical wingtip planes was considered poor, particularly in take off and landing operations and single-engine operations. It was proposed to eliminate these surfaces and replace them with a conventional empennage.
The effectiveness of the ailerons on landing was diminished due to their use as elevators, which was considered unnecessary. It was proposed to work on increasing the effectiveness of these surfaces.
The absence of suspension on the landers made landing difficult. The plane tended to jump after touchdown. Sometimes these jumps were so great that the pilot was forced to give up the throttle again and go up to make a new turn over the aerodrome. It was recommended to add oleo-pneumatic amortization systems. In the same way, it was decided to modify the tail skid to provide it with orientation in order to improve the operation on land.
Flying the plane from the navigator’s cockpit was impossible due to the lack of completeness of the navigation equipment.
The maximum speed obtained of 219 km/h was lower than that of the planes of the time. This was explained by the poor aerodynamic quality of the structure, which had many exposed surfaces and the already obsolete M-22 engines. The advantages of the tailless configuration were affected by the large size of the fuselage.
The defensive capability of the VS-2 was generally superior to that of any tailed aircraft. This model was characterized by the simplicity of the solution to the problem of defense of the rear and upper hemispheres. Despite this, the VS-2’s armament left a lot to be desired. The firing points did not guarantee the total defense of the aircraft and the defense of the aircraft against attacks from below was not guaranteed in any way. The protection of the firing positions was considered deficient.
The cockpit was valued very well. Visibility during the flight and take off was quite good. In the cabin in summer it was quite hot, even after lowering the glass on the left. The teams on the blackboard had a good distribution, with the exception of the variometer, which was very low and it was difficult to see the status.
The overall assessment of the aircraft in the NII VVS report signed by Filin and Markov highlighted that the VS-2 2M-22 (K-12) aircraft was of great interest as an experiment in creating a flying wing configuration aircraft in a military configuration. It was considered that this scheme presented advantages in relation to the conventional system in terms of visibility, cleanliness for defence and take-off and landing operations at low speeds.
However, in the version presented, the VS-2 had very poor performance and poor weapons, so it was impossible to consider it a modern military aircraft. The model was considered experimental.
It was recommended to return the plane to its builders in order to improve all the problems. It was proposed to GUAP make these changes and begin factory tests for March 1, 1938. Then submit it for carrying out the full program of state tests.
On December 8, 1937, V. Smushkievich signed the NII VVS report and requested to insert into the experimental construction plan for 1938 the development of an experimental aircraft on the VS-2 scheme with technical requirements and armament in correspondence with a modern military aircraft. The possibility of serial production will be evaluated only after the completion of the state tests.
For two months the plane was overhauled, installing more powerful M-25 engines with variable-pitch metal propellers and electrically-operated retractable landing gear. The weapons were also modified. With these modifications the maximum speed increased to 420 km/h. After finishing the factory tests, the improved aircraft was delivered in April 1938 to the evaluation commission, which approved its serial production.
The K-12 “Zhar Ptitsa” demonstrated at the Tushino air parade was the only aircraft built. On April 1, 1938 K. A. Kalinin was arrested. According to the opinion of the Military Collegium of the Supreme Court of the USSR, he was accused of being an “enemy of the people” and shot. It has been speculated that the builder could have sold information to John Northrop about his studies on the subject of flying wings and also that he had relations with German espionage, but none of these theories have been proven.
The leadership of the aviation industry decided to cancel all the works of this builder, including the destruction of 10 copies that had started production at the Voronezh factory and were at different stages of completion. The lone K-12 was also destroyed after removing all useful equipment and constructive elements. An important part of the project documentation disappeared.
Kalinin K-12 Powerplant: 2 × Shvietsov М-22 480 hp Wingspan: 20.90 m Wing area: 72.70 m² Length: 10.30m Height: 3.65m Empty weight: 3070 – 3210 kg Normal take off weight: 4200 kg Wing loading: 57.8 kg/m² Power load: 4.38 kg/hp Fuel capacity: 900 kg Oil capacity: 90 kg Speed at sea level: 211 km/h Maximum speed at 3000 m: 228 km/h Cruising speed: 189 km/h Practical range: 1100 km Practical ceiling: 7170 m Landing run: 700 m Take-off run: 700 m Armament: two 7.62 mm ShKAS machine guns Bomb load: 500 kg. Accommodation: 3
The K-7 was an exceptionally large experimental bomber of 1933, having two faired underslung tandem-wheel landing-gear units and six engines. Designed by World War I aviator Konstantin Kalinin, the K-7 was one of the biggest aircraft built before the jet age. As originally designed the K-7 was to have engines in the undercarriage sponsons. As completed the bomber had gun positions, the bomb load and an internal staircase as well as two large wheels in each massive sponson.
It was powered by seven engines, six pulling on the wing leading edge and one pushing at the rear. The K-7 was one of the first metal aircraft with a twin-boom layout. The K-7’s control surfaces were all deflected by the use of large trim tab surfaces mounted on struts. The K-7’s very brief first flight showed up instability and serious vibration caused by the airframe resonating with the engine frequency. The solution to this ‘flutter’ was thought to be to shorten and strengthen the tail booms, little being known then about the natural frequencies of structures and their response to vibration. On the 11th flight, during a speed test, the port tailboom vibrated, fractured, jammed the elevator and caused the giant aircraft to plough into the ground. The K-7 was said to have had a pilot, 18 crew members and one passenger when it crashed, killing all but five crew. Undaunted by this disaster, Kalinin’s team began construction of two further K-7s in a new factory, but the project was abandoned.
Engine: 7 x M34F, 550kW Max take-off weight: 38000 kg / 83776 lb Empty weight: 24400 kg / 53793 lb Wingspan: 53.0 m / 173 ft 11 in Length: 28.0 m / 91 ft 10 in Wing area: 454.0 sq.m / 4886.81 sq ft Max. speed: 234 km/h / 145 mph Cruise speed: 180 km/h / 112 mph Ceiling: 4000 m / 13100 ft Range: 3030 km / 1883 miles Crew: 12 Passengers: 128
The K-5 had an enclosed two-seat crew cabin forward of the wing leading edge and an eight-seat passenger cabin. 260 built were produced from 1930, before production terminated in 1934. Installed powerplants included the 335kW M-15 (Bristol Jupiter built under licence), 358kW M-22 introduced in 1931, and the M-17F of 544kW in final series aircraft. Widely used on passenger services within the Soviet Union, some K-5s were still flying in 1940.
Engine: 1 x M-22, 355kW Max take-off weight: 4000 kg / 8819 lb Empty weight: 2500 kg / 5512 lb Wingspan: 20.5 m / 67 ft 3 in Length: 15.9 m / 52 ft 2 in Wing area: 56.3 sq.m / 606.01 sq ft Max. speed: 190 km/h / 118 mph Cruise speed: 150 km/h / 93 mph Ceiling: 4500 m / 14750 ft Range: 800 km / 497 miles Crew: 2 Passengers: 6
Ukrovozdukhput manufactured aircraft to the designs of K. A. Kalinin, who patented the elliptical wing planform in 1923. One of his best-known designs was the 1928 Kalinin K-4 single engined cabin monoplane, produced as a transport or air ambulance.
Konstantin Alexeyevich Kalinin (Russian: Константин Алексеевич Калинин) was born on December 29, 1899 in Warsaw. His father, a retired military man, died when he was only three years old. He completed his first studies at a local seminary.
During the 1905 disturbances in Russia, the young Kalinin was accused of distributing revolutionary bulletins, for which he was detained for four months. After being released he continued his teacher studies.
Between 1909 and 1912 Kalinin studied at the Odessa Higher Military Artillery School and after graduation was assigned to Vladivostok. A year later he would get married and have his first contact with aviation. Near the barracks where he was, was one of the first aviation units of the Russian Empire and these planes greatly impressed the young man, who requested to be transferred to a flight school, but was not allowed.
At the beginning of World War I Kalinin served as an artillery officer, but by February 1916 his dream of aviation came true when he was allowed to enter the Gatchina Military Flight School, graduating in December. The recently graduated pilot was assigned to the 26th Aviation Corps stationed on the Romanian front, where he flew reconnaissance missions in Farman and Voisin biplanes, receiving the Imperial Orders of Saint Stanislav, Saint Anne and Saint Vladimir.
After the October Revolution Kalinin joined the Red Army, serving as a pilot during the civil war and joining the ranks of the Communist Party in 1920. On June 1 of 1920, Kalinin entered the Moscow Aviation Technical School, created by Professor N. Ye. Zhukovski in 1919 and for the month of October, due to his excellent results, he validated the first year. By March 1921, Kalinin became head of the scientific-technical section of the school.
In 1922, his membership within the Communist Party was suspended on charges of sympathizing with the counterrevolutionary bands of the Ukrainian nationalist Petlyura and of party inactivity, but he was reinstated in June at the request of a member of the VS school party committee, Ilyushin, but in November he left the institution.
Kalinin moved to Kiev, where he started working at ” Remvozdux-6 ” aircraft repair factory as head of production. This factory, created in 1920, was dedicated to the repair of Red Army aircraft, mostly licensed model aircraft used during the First World War. Since his arrival, Kalinin grouped under his direction a design group made up of a technician (DL Tomashevich), two designers and two students linked to practical work: AT Rudenko and AN Gratsianski.
Determined to continue his studies at the end of 1922 Kalinin entered the Kiev Polytechnic Institute, where a year later he would be elected secretary of the Aviation Scientific Society. By 1923 he patented an elliptical wing of his own design, which would later be used on his civilian models. His graduation project in 1925 was the K-1 (RBZ-6) transport aircraft. Kalinin personally participated in the first flight of the K-1 and ended up graduating as a mechanical engineer. From that moment on he became one of the most renowned Soviet aircraft builders of the interwar period.
In 1926 Kalinin was transferred to Kharkov , where he was selected as chief designer of the UkrVozduxPut company, which was in charge of managing flights on local lines. Under his direction there were two designers, three specialists in wing configuration, fuselages and propellers, and two technicians.
The basis for his new KB was established in the aircraft repair shops of the UkrVozduxPut, which at that time was engaged in the repair of German Dornier aircraft used by Soviet-German airlines. This workshop had 25 workers and two German specialists on its payroll.
On September 17, 1926, these workshops, together with Kalinin’s team, would become the Kharkov Aviation Factory and would lay the foundations of the Kharkov Aviation Institute (JAI) , by creating classrooms for the preparation of workers. The Kharkiv Institute of Technology also created an aviation department for the preparation of engineers, which some time later would be transferred to the JHA.
Later, an aerodynamic laboratory was built where a 2-meter wind tunnel was installed in which Kalinin’s second model, the K-2, would be tested.
KA Kalinin in the second half of the 30s.
The work of the Soviet specialists in the UkrVozduxPut soon created problems with the Germans, which came to a head when the German model Dornier Mercur found a competitor in the domestic model K-2.
The leadership of the UkrVozduxPut was divided, with the supporters of the foreign model winning. As a result, Kalinin’s group was decremented, new specialists from Kiev were brought back, and development of the K-2 was halted.
In these circumstances, the Ukrainian government took action on the side of Kalinin. Soon the pro-German leadership of the UkrVozduxPut was removed from their posts, the Dornier Mercur was not bought and the K-2 was built and tested. Despite the fact that the K-2 did not show superiority in relation to the K-1 and was not produced, it served to prepare the mechanisms of the industry and was soon followed by more successful models such as the K-4 of 1928 (39 built) and the 1929 K-5(260 built), which managed to lay the foundations for national civil aviation, which meant the end of German dependence.
After some civilian models, Kalinin began the development of military models with the gigantic K-7 bomber, which would be destroyed during tests in 1933. Two improved models, one as a bomber and one as an airliner, began construction in Voronezh, but were abandoned in 1935. Later military aviation development was continued with the K-12 (VS-12) tailless bomber.
Kalinin ‘s KB was transferred to the Voronezh Aviation Factory (Factory No.18) where development of the K-12 continued. The new model had been ordered for production but the evaluation in the tests led to its configuration being considered as lacking in perspective and the development was abandoned (dragging with it other aircraft with a similar configuration such as the Moscaliov SAM-7).
In April 1938 he would be arrested on the charge of “enemy of the people” and shot in the Voronezh prison on October 22. His construction bureau was liquidated.
KA Kalinin’s career in aviation lasted only 13 years, in which he designed 16 models. Most of Kalinin’s designs were high-wing, elliptical-shaped, braced monoplanes with a tubular steel structure and wood and fabric covering, characteristic of his time.
