Aviation of World War II
Soviet Gyroplanes in WW II
The construction of the first domestic autogyro KASKR-1 was started in 1928 under the guidance of engineers Nikolai Kamov and Nikolai Skrizhevsky. In 1929, a car piloted by pilot Mikheev, with designer Kamov on board, took off.
Double autogyro had an aircraft-type fuselage, a small wing, a power plant with a pulling propeller. The autorotating rotor - braced type, four-bladed - was located above the front cockpit. The blades were attached to the hub using vertical and horizontal hinges. The design of each included a steel tubular spar, a set of wooden ribs, plywood and canvas sheathing. In the future, a similar design was used on all domestic autogyros and the first helicopters, including the Mi-1, Mi-4.
The main rotor axis was fixed. Longitudinal and transverse control of the apparatus was carried out using aircraft controls: ailerons, elevators and rudders.
The takeoff weight of the device is 930 kg. Subsequently, a more powerful engine of 230 hp was installed on the KASKR-2 autogyro, which made it possible to obtain a maximum speed of 110 km / h. The minimum had an amazing value - 35 km / h! These two types of gyroplanes performed 79 test flights.
The A-7 gyroplane became even more advanced Kamov's apparatus. The design of the machine began in 1931 in the section of special designs of TsAGI. The design team was headed by N.I. Kamov. This creative team also included M.L. Mil.
A-7 was created according to the terms of reference of the Air Force and was intended for adjusting artillery fire, communications and close reconnaissance. It was also envisaged to use the machine from the ships of the Navy. It was a winged autogyro with a mechanical spin-up of the main rotor before takeoff, which was carried out from the engine with the help of a transmission.
The fuselage of the truss structure had two cockpits: the pilot's and the observer's. The low-lying wing folded up at the junction with the center section, which, in combination with the folding blades, ensured the convenience of transporting and storing the apparatus in hangars and on ships.
The A-7 had a tricycle landing gear with a nose wheel and an auxiliary tail support. The landing gear was equipped with hydraulic damping.
The three-bladed main rotor was located above the fuselage in front of it. The blades were distinguished by the care taken in manufacturing and balancing. Steel spar of elliptical section had three joints. The tail stringer of the blade was cut in three places to ensure that the blade deformation in the plane of rotation was acceptable in flight. The aircraft-type propeller power plant included a fixed-pitch wooden propeller and an M-22 air-cooled engine.
The designer paid special attention to the streamlined aerodynamic contours of the airframe. The landing gear and main rotor mounts, as well as the wheels, were covered with fairings.
Small arms included a front fixed mount with a PV-1 machine gun for synchronous firing through the propeller rotation plane (500 rounds of ammunition) and a rear turret with a Degtyarev machine gun (12 magazines). Bomb armament provided the suspension of two 250 kg bombs or four 100 kg each.
The autogyro had a transceiver station 13 SK-3, later replaced by RSI-3. For planned photography, a PO1TE 1B camera was installed.
Tests of the A-7 began in 1934. During them, the following flight data were confirmed: takeoff weight - 2300 kg, crew - 2 people; engine power - 480 hp; full load - 800 kg, maximum speed - 221 km / h; flight duration - 4 hours; take-off run - 28 m, run - 18 m.
For comparison, the data of the Sierva Avra C-40 gyroplane, built in 1938 under the guidance of the first inventor of this apparatus, the Spanish engineer Juan de la Cierva: takeoff weight - 885 kg; crew - 2 people; engine power - 175 hp; full load - 272 kg; maximum speed - 193 km / h.
In early 1941, Narkomles and Aeroflot organized an expedition to the foothills of the Tien Shan to prove the possibility of using gyroplanes in forestry and agriculture. The mountain slopes were covered with thousands of hectares of orchards, which suffered from an insect pest - apple moth. The autogyro coped with such tasks as well, if not better than the aircraft. Firstly, the rotorcraft did not need large areas for takeoff and landing; secondly, the air flow from the rotor directed the flow of pesticides straight down, and the efficiency of their application increased. The expedition spent a month in the foothills of the Tien Shan, and even the central press noted the results of its excellent work. The Pravda newspaper wrote about the experiment with a pollinating autogyro:
“Participants of the aviation chemical expedition of the timber industry trust of the USSR People's Commissariat of Forests have recently returned to Moscow. The expedition conducted an experience of using a Soviet autogyro designed by engineer Nikolai Kamov to control pests of fruit trees in South Kyrgyzstan. Piloted by pilot Vladimir Karpov, the A-7 went up steeply and, tacking along steep mountain slopes, quickly reached areas inaccessible to aircraft. The device easily maneuvered in narrow valleys, descended into bowl-shaped mountain tracts, turned around at the bottom and rose again. 32 flights were performed by an autogyro ... "
Back in the spring of 1940, on the initiative of N. I. Kamov, the first plant of rotary-wing aircraft in the USSR was created at the Ukhtomskaya station. Subsequently, it was from this small enterprise that the Ukhtomsk Helicopter Plant grew, which today bears the name of its creator. Kamov was appointed director of the plant and chief designer, and M. L. Mil became his deputy. In the middle of 1940, the plant began building five A-7-Za military gyroplanes. Pilot Kositz began their tests.
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With the beginning of the Great Patriotic War, five A-7-Za formed a separate gyroplane squadron - the first part of the rotorcraft in the Red Army Air Force. Kamov himself recalled the actions of his autogyros in battles against the Nazi invaders:
“The gyroplane detachment, organized by the Main Artillery Directorate, operated as part of the 24th Army in the area of the city of Yelnya and was based at one time at the airfield in the village of Podopkhay. The pilots of the detachment under the command of Senior Lieutenant Trofimov made a number of sorties to correct artillery fire and behind enemy lines to the partisans. The flights were carried out day and night.
Night flights were especially difficult. This was our first experience, and in war, as they say, one does not hesitate for a long time. As soon as the gyroplanes arrived at their location, the very next day, the command ordered to prepare for a combat mission at night. Flights were made in complete darkness. There was no talk of any lamps, at least "bats". The front-line airfield was only twenty kilometers from the front line. A few days before the arrival of the gyroplanes, the Germans spotted the airfield and nine "Messers" bombed it to smithereens. The commander of the fighter regiment, which was at this airfield, was constantly wary of another German raid. Therefore, as soon as the autogyro taxied out of cover to spin the propeller before takeoff, fuss began around the car and swearing was heard: “Take off soon !!! Don't freak out!" etc. At night, takeoffs and landings were carried out in complete darkness - only by the sound of the engine it was possible to determine where the car was and what was happening to it. If it buzzes, then it's intact ... "
Kamov knew all this not from the stories of pilots and technicians. He visited the front together with his deputy M. L. Mil. The main task of the designers at the forefront was the repair of gyroplanes damaged in battle.
In early October, the gyroplane squadron will relocate to the east. Two cars flew over to the 43rd Army. Two of those remaining in the A-7-Za unit were sent to Moscow for repairs, and on the third squadron commander Trofimov was instructed to urgently deliver a report to the headquarters of our troops in Gzhatsk. In a report signed by the leadership of the 24th Army, it was reported that the Germans had made a breakthrough at the junction of the 24th and 43rd armies. The flight was carried out in complete darkness, which protected the low-speed vehicle from the attacks of German fighters. But landing in such conditions was very difficult to perform. The pilot at dusk mistook the forest for the ground cover of the airfield and parachuted onto it from a height of 10 meters. The autogyro was seriously damaged, but Trofimov survived, and the package with the report was delivered on time. This episode was the last in the combat career of the rotary-winged reconnaissance and spotter A-7-Za designed by N. I. Kamov.
With the threat of the capture of Moscow, the plant was evacuated from Ukhtomskaya to the village of Bilimbay, Sverdlovsk Region. Here Kamov and his associates repaired the surviving A-7s. But the chief designer was already thinking about a new rotary-wing machine - the "jumping" autogyro AK (artillery spotter), the design of which began just before the war. This gyroplane with an MV-6 engine (225 hp) had main rotor control like on modern helicopters - with the help of a swashplate that changes the cyclic pitch of the blades. In difficult conditions of evacuation, the construction of the machine turned out to be impossible. The plant in Bilimbay was redesigned for the repair of automotive and aviation equipment, and N.I. Kamov was able to start design work only after the war, he no longer returned to gyroplanes, completely switching to the creation of helicopters.
Autogyro over the Mannerheim Line
It is traditionally believed that Soviet gyroplanes were first used in combat operations in August 1941 near Yelnya. But it's not. The baptism of fire of domestic rotorcraft occurred a little earlier - during the "winter" war with Finland.
On December 19, 1939, by order of the then head of the Air Force Directorate AD Loktionov, an experimental group of gyroplanes was created under the Directorate of the Chief of Artillery of the Red Army. The group received only two devices. Both of them were experienced—A-7 and its understudy A-7bis. The entire personnel of the group - both flight and technical - were taken from plant No. 156.
Both vehicles allocated to the group were well-deserved. A-7 was designed in the department of special designs of TsAGI under the leadership of N. I. Kamov. Brigade No. 3, which he led, was engaged in the creation of a heavy military autogyro. Similar work has been carried out since the end of 1931. A-7 was not the first military autogyro in our country. Before him, the A-4 (A. M. Cheremukhin) and A-6 (V. A. Kuznetsov) were designed as military ones. A-4s were even released in a small series - 13 pieces, of which 10-11 ended up in military units.
But both the A-4 and A-6 were light vehicles, intended mainly for communications. Kamov's gyroplane was supposed to become a combat vehicle. Its main purpose is to conduct close reconnaissance and adjust artillery fire. It could also be used for communication, and could also support troops on the battlefield with machine gun fire and small bombs. It was the first Soviet autogyro with weapons. He carried three machine guns: one synchronous in the front of the fuselage and two on a pivot mount at the shooter. Beams of bomb racks were located under the wings. Chemical weapons were also envisaged, which were then actually tested in February-April 1936.
The A-7 prototype was built at the TsAGI Experimental Design Plant (ZOK) in April 1934. On September 20, the pilot S. A. Korzinshchikov made his first flight on it. Factory tests were completed already in 1935, in the same year he was evaluated as a spotter at the training ground near the Fruktovaya station. In 1936, the A-7 passed state tests, and in 1938, special artillery tests at the Luga training ground near Leningrad. At the same time, he was involved in the operation to rescue the Papaninites, but he did not manage to make a single flight from the Yermak icebreaker, on which he was stationed - the polar explorers had already been evacuated. In total, by the end of 1939, the A-7 had flown about 90 hours.
The A-7bis, a stand-in for the A-7, was newer. It was manufactured by plant number 156 (the same ZOK after renaming) in May 1937. The understudy differed from the A-7 in the horizontal tail and the design of the rotor boar. Due to various changes, it was about 100 kg heavier. This reduced the maximum speed from 200 to 194 km / h, and the service ceiling from 4800 to 3600 m. The A-7bis managed to pass factory, state and special artillery tests at the Totsk training ground near Saratov. The autogyro flew about 80 hours.
Packaged gyroplanes were sent from Moscow to Leningrad by rail. The assembly was carried out at the Leningrad plant No. 47. The A-7bis had to change the engine (M-22.480 hp). The old radio stations 13-SK were removed and mounted by more modern RSR-3.
On the A-7, during the second test flight, the front ski (gyroplanes had a three-wheeled landing gear, and the wheels were changed to skis on the occasion of winter) hit the propeller. The ski itself, the screw, the motor mount were broken and the skin of one of the main rotor blades was damaged. The investigation showed that the cause of the accident was incorrect adjustment of the ski braces. A-7 had to be abandoned in Leningrad. The composition of the experimental group was reduced to one machine.
This single A-7bis flew to a field airfield on Lake Kauk-Järvi. The 1st separate corrective air squadron was located there on SSS (ZS) aircraft. An experienced group actually joined this detachment and made combat missions with it. A-7bis was used as a regular spotter aircraft. In terms of speed, of course, it was significantly inferior to the CCC, but it was significantly superior in maneuverability and takeoff and landing qualities. Heavy artillery fire was corrected from the autogyro.
In the conditions of complete air supremacy achieved over the small number of Finnish aircraft, even in the daytime, the slow-moving A-7bis was not particularly threatened by enemy fighters. We never had to fight off the Finnish Bulldogs and Gontlits. The Finns also did not have a well-organized air defense system. During the entire time of participation in the war, the autogyro had several minor breakdowns, but did not receive any combat damage. At the front, the A-7bis often flew with an overload of up to 2300 kg (with a nominal take-off weight of 2245 kg).
In total, the gyroplane made 20 sorties, flying a total of 11 hours and 14 minutes. After the signing of the armistice, both cars - both the A-7bis and the A-7, which had stood all this time at plant No. 47, were returned to Moscow. A-7bis then participated in a number of experimental programs aimed at determining the possibilities of its application in civil aviation. And in the Great Patriotic War, other gyroplanes, improved A-7-Za, already participated, a small series of which was released in the spring of 1940.