Zveno / Link
The TB-3 bomber was used by engineer V.S.Vakhmistrov in 1930-1940 during the development of the aviation project "Link", based on the use of a carrier aircraft carrying from one to five fighters to increase their range. The complex "Zveno-SPB" (composite dive bomber), created for this project, also took part in the first period of the Great Patriotic War.
During the early years of flight, it was evident that no one aircraft could embody all desired flight characteristics. Long range and high speed seemed to require different designs. The problem of providing aircraft with fuel while in flight is a very important one. It is well known that dirigibles and large bombing iplanes are almost completely at the mercy o the small, easily maneuverable, pursuit planes, and that it is almost essential that in every bombing expedition the dirigible or large bombing planes must be accompanied by an escort of pursuit planes for purposes of defense. However, the small weight carrying capacity of these small fast planes permits them to carry only two or three hours fuel and thus limits their range of operation to such a considerable degree' that it is impossible to conduct a bombing expedition any great distance into the enemy territory.
One solution was aerial refuelling, which allowed aircraft to receive fuel while in flight and today is common for many large air forces. It is the equivalent of refuelling your car by connecting it to a tanker truck while driving down the highway at high speed. In 1917, a pilot in the Imperial Russian Navy, Alexander P. de Seversky [aka Alexander Prokofiev-Seversky], proposed increasing the range of combat aircraft by refuelling them in flight. De Seversky soon emigrated to the United States and became an engineer in the War Department. He applied for and received the first patent [US1728449A] for air-to-air refuelling in 1921.
The transfer of the fuel from the large airplane to the smaller airplane remained a challenging task. Some schemes involved the somewhat cumbrous operations of passing a line from one aircraft to the other, making a connection to a refuelling hose and passing the hose back again for connection to a refuelling coupling. Others involved the larger aircraft simply towing the smaller aircraft, as was eventually done with considerable success with transport aircraft [typically with two engines] towing larger gliders [with no engines]. Or the larger aircraft might simply carry the smaller vehicle, an architecture that eventually produced the air-launched cruise missiles of the Cold War.
For "Link", TB-1 and then TB-3 bombers were used as carriers of fighter aircraft. To them I-4, I-5, I-Z and I-16 fighters were suspended. The first successful flight took place on December 4, 1931. The pilots: airstrikes - A.I.Zalevsky, the second pilot - A.R.Sharapov. At the I-4 - V.P.Chkalov and A.F.Anisimov. This initial variant, called "Link-1", consisted of a heavy bomber TB-1, carrying two I-4 fighters on the wings. In September 1933, I-4 fighters were replaced by I-5, and the new version was called "Link-1a". Pilots were Stefanovsky, who piloted the carrier, as well as Kokkinaki and Grosd, who piloted the fighters.
In the version called "Link-2", TB-1 was replaced by TB-3, and the number of fighters was increased to 3, one of which was now located on the fuselage. In August 1934 the flight of a new version took place. In order to achieve greater takeoff power from the upper fighter, tail and horizontal tail systems were removed - but this did not give the desired result.
In the new version called "Link-3", the I-5s were replaced by I-Z monoplanes concerning the landing gear during take-off and landing, and therefore, for landing purposes, fixed on a "floating" vertical fastening. To fix the "dangling" aircraft the mechanism of attraction and rigid fixation of the suspension after take-off was invented - the timely use of this mechanism required from the pilot not just ability - but flair.
In one of the test flights, the pilot Korotkov, apparently, prematurely pulled the handle on himself, being afraid of being late again, as on take-off. Closely closed rear stop jumped out, "Zet" immediately moved to a large angle of attack. One wing stopper could not stand the load and broke. A skew appeared, which tore the stop of the other wing. The fighter crashed into the plane TB-3, and his propeller was shattered. Mastery of the pilot of the carrier allowed avoiding a general catastrophe, but the pilot of the emergency fighter landing was lost.
In order to avoid further such fatal accidents, in the variant "Link-5" (the variant "Link-4" was canceled), it was decided not to take off and sit down with a suspended fighter. Now one fighter (also I-Z) was clinging to the TB-3 carrier under the fuselage after its take-off. The first test took place on March 23, 1935, with the participation of Stefanovsky, who piloted the carrier, and Stepanchyonok, who piloted the fighter, showing the feasibility of such an option.
The four-meter frame constructed for this purpose in the retracted position was located between the chassis along the fuselage of the carrier aircraft. Being released to receive the fighter, it was installed vertically, dropping much lower and ahead of the wheel. The frame ended in a crossbeam. The fighter on top of the fuselage, in front of the pilot's cabin, had a hook with a lock from the bomb holder. The process of connecting planes took place in such a sequence. In the air, above the airfield, the fighter very accurately approached the bomber, got attached to the released farm, hooked on his hook for a crossbar - mooring. Then the frame with the help of special mechanical devices was pulled up to the fuselage of TB-3, the wings of the fighter, rested against the carts of the wheels of the carrier aircraft. Launch was carried out in the reverse order.
Due to the fact that one fighter under the fuselage was not enough for a reliable cover for the bomber carrying it, and with the fact that in this version the fighter could not carry a bomb load exceeding the usual weight, it was decided to return to the suspension of a pair of fighters under the wings.
In the new version called "Link-6" was used rigid pyramidal fastening of fighters, which were used as I-16 type 5. Two such fighters rolled on their own wheels under the planes of the carrier aircraft and attached to it with the aid of locks of bomb holders. Then they cleaned their chassis, and "Link-6" rose into the air. The first flight took place in August 1935. Stefanovsky (TB-3), as well as Budakov and Nikashin (I-16) took part in the flight.
As early as November 20, 1935, an aircraft carrier flew with five fighters, known as "Aviamatka". In this variant, during takeoff and landing, two I-16 fighters were under the wings, two I-5s on the wings, and one I-Z hooked and uncoupled under the fuselage already in flight. During the test, the aircraft carrier was piloted by Zalevsky, and the fighters by Stefanovsky, Nikashin, Altynov, Suprun and Stepanchonok.
In July 1937, the variant "Link-SBP" was tested, where the SPB means - Composite Dive Bomber, who later took a real part in the war. In the first flight of this flying aircraft carrier, Stefanovsky (TB-3), as well as Nikolev and Taborovsky (I-16s) took part. And already in 1938 Vakhmistrov, introduced the Commission "Link-SBP" in the following version: carrier - Tupolev TB-3-4AM-34FRN; two fighter aircraft - Polikarpov I-16 type 5, carrying two 250 kg of the FAB-250 bomb.
Throughout 1938, work was carried out to refuel fighters on a carrier, with the goal of creating an air carrier carrying eight I-16 fighters capable of refueling from an aircraft carrier without landing on land. According to this version, it was assumed that the aircraft carrier would take off with two fighters under the wings, while the remaining six fighters would be attached to it already in the air. The project of a carrier with eight fighters was never implemented.
Later, in November 1939, a variant with three I-16 fighters attached to the aircraft carrier TB-3 in the air was tested. The variant was called "Link-7".
Battle baptism of the "Link-SPB" took place on July 26, 1941, when after a number of failures of conventional bombers, unsuccessfully trying to bomb the Charles Bridge on the Danube, it was decided to use aircraft carriers and to check was given the mission to bomb the "SPB" oil storage in Constanta. The task was successfully completed - the target was hit without loss, during the air strike, the fighter-bombers disconnected from the cargo of bombs from the carriers at a distance of 40 km from the target, and after the defeat the targets returned to the airfield in Odessa, where they refueled and returned to Evpatoria on their own.
In connection with the successful demonstration of the Sven-SPB capabilities, on August 10, 1941, an air strike was carried out for the main purpose - the Charles I [Chernovodsk] Bridge on the Danube, through which, in addition to the troops, the Ploiesti-Constanta oil pipeline also passed. For this, the fighters were additionally equipped with a 95 liter fuel tank, to get an additional 35 minutes flight. The attack was carried out by three carriers, but in one of them there was a breakdown, and he was forced to go back, the rest fired bombers 15 kilometers from the Romanian coast. Fighter bombers made a successful attack at a peak from a height of 1800 m and returned without loss.
The repeat flight took place two days later - on August 13, 1941, this time there were no vehicle failures and the fighter-bombers could significantly damage the bridge. The fighters attacked the Romanian infantry near Sulin on the way back, returned without loss. Fighter bombers made a successful attack at a peak from a height of 1800 m and returned without loss.
on August 13, 1941 Sovinformburo reported: "As already noted in the Soviet Information Bureau's evening report of August 11, Soviet pilots destroyed the Romanian railway bridge across the Danube River near the station. Chernovod, which is 60 kilometers west of the port of Constanta. The significance of the brilliantly executed by Soviet pilots operation on the bombing of the Chernivodsky Bridge is enormous. Through this bridge, all the railway communication between the main centers of Romania and the entire Romanian Black Sea coast passed ... Oil storage on the Black Sea coast can not now be replenished with fuel, since simultaneously with the bridge the oil pipeline laid under the lower deck of the bridge was destroyed ... "
Later the planes of the "Link" attacked the crossing of the Dnieper and the German columns in the fighting at Perekop. Bombing in the group stopped in the autumn of 1941 due to the high wear of the engines of the bombers "Link" and the gradual increase in the number of Pe-2. The remaining TB-3 of the same modification, the release of which was discontinued as far back as 1937, was considered expedient to use as transport.
On June 18, 1945, three TB-3 aircraft were included in the air column of the Victory Parade, but the flight of the column was canceled due to heavy rain and low clouds.
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