In June of 1938 ended the state tests of the aircraft maintenance DB-3 with engines M-85 (factory designation TSKB-54) and machine-gun armament. The emergence of such aircraft was an echo of the concept of the use of bombers in those years. The limited range of fighter planes, not allowing them to accompany bombers on the full range, led to the creation of a new class aircraft cruisers. Weapons TSKB-54, with the exception of machine guns possessed insufficient field of view of sight and which have an impact on directional stability, passed the tests, but the plane returned to the factory for modifications and the following year went on the test. However, before adopting it did not come.
In 1938 the Ilyushin long-range bombers were equipped with three air armies. In December of the same year, the BBC held a conference to exchange experience in the operation of bombers. The representative of the Monino aviation brigade (1-AON) noted that the two-year operation of the DB-3 though, and confirmed compliance characteristics of the aircraft tactical-technical requirements but the car proved extremely difficult to operate, had many manufacturing defects. This was especially true of the aircraft of the 18th of the plant. There were leaks and cracked fuel tanks, often brakes failed and destroyed elements of the main landing gear. For the latter reason only in the summer of 1938 slammed three cars.
The first serious test of the DB-3 was the war with finami winter 1939/40 year, revealed hidden flaws bomber. First of all, noted the low reliability of the engines M-87 compared to M-25, M-62 and M-103, which often led to accidents.
The disadvantages attributed too much running on wheels that reached up to 800 — 1000 m take-off weight 8500 — 9500 kg. to Reduce the run could only be possible by installing new variable-pitch propellers — VISH-23. No better was the case with non-retractable skis, which are constantly frozen to the snow in the Parking lots and even at bus stops. Practice has shown the expediency of the operation of the aircraft on wheels with the rolled snow.
Finnish fighter pilots quickly discovered the “dead zone” DB-3 and preferred to carry out attacks back hem. Then under the leadership of a Junior officer of the 21st, dbap, Bobko produced, in addition to Lugovoi (which had a field of fire 60° from the vertical), the fourth ventral machine-gun fast otvalilsya Finns from attacks from below.
But the biggest challenge for ground staff became heated engines at temperatures down to -50°C. the Winter was very harsh, as if specially prepared for the test of man and technology. However, the experience of the Finnish war later in full and not taken into account.
A special place among the modifications of the DB-3 is stratospheric bombers. The first of these was the project SIDE-17, developed before the war to KB-29 under the leadership of N. N. Kashtanova. The pressurized cabin with the boost from the superchargers installed on the engine, turned on and the power circuit of the fuselage. Thus for life support crew to the heights of 8 — 10 km in the case of lumbago pressurized cabin with bullets of 12.7 mm caliber (the crew worked without individual oxygen masks) required the installation of more powerful engines M-88. But soon from the concept of stratospheric bombers refused, and that was the reason for the termination of work on the SIDE-17.
In the course of the war to the idea of the pressurized cabin of the Il-4 was back again. March 16, 1943, test pilot V. K. Kokkinaki made the first flight on high-altitude reconnaissance-bomber, the Il-4TK with motors M-88B equipped with turbochargers TK-3. Integrated pressurized cabin ventilation type for the pilot and Navigator was to provide a long flight in relative comfort at altitudes of about 11 km and Then decided that high altitude will be protection from enemy fighters. However, above 9300 m the plane did not rise. For fine-tuning the machine needed time. By mid-1943, when the Soviet air force was practically dominated by the sky, stratospheric bomber has lost its relevance.
The silts above the sea
The advent of the torpedo bomber DB-ZT was preceded by a failure with a specialized machine T-1, developed at TSAGI. Unlike Tupolev aircraft, torpedoes weighing up to 940 kg were placed not in gruzootseke and podunajska cachedtitle T-18. Depending on the task the plane was able to drop low-altitude torpedoes 45-36-an from a height of about 30 m at speeds of 240 — 260 km/h and altitude 45-36-AV, with altitudes of 250 — 400 m — at all speeds. With this purpose, the last manned parachute, and after landing and unhooking the parachute, the torpedo was moving in the mode of circulation in a spiral to the goal. Low-altitude torpedo was carried out using sights PTN-4 PTN-5, and altitude — using OPB-1m. if necessary, the torpedo could use a normal bomber weapons and to carry out setting MIN.
DB-3T passed state tests in the first half of 1938 and was issued as a separate series.
In the prewar years were still dominated by views that the naval aircraft must be amphibious if not, at least, can be based on water as on land equipment still does not provide the necessary safety of flight over water. In this regard, created a float torpedo bomber DB-3ТП. In the same 1938 he commissioned a series of 15 such machines. However, after state tests confirmed the earlier assessment of a significantly reduced flight performance (although complying with the requirements) have been forced to stop further work.
In the prewar years, the personnel mentoring regiments were preparing for war at sea, but in 1941 their task has changed dramatically. Instead of fighting enemy ships with torpedoes Prime targets for “sludge” steel columns of Nazi troops. Sometimes they are used for setting minutes the Situation changed in 1942, when the crews of the DB-3T, and then the Il-4T is being increasingly used for torpedo attacks on enemy ships.
Il-4
The first case of combat use of the torpedo in the USSR, recorded July 29, 1942, the day a pair of DB-3F from the 24th of mtal (senior captain I. Y. Garbuz and driven by B. S. Gromov) sank two transports with a total displacement of about 20 kt near the coast of Norway (Porsanger-Fiord).
7 October of the following year Il-4T of the 5 th guards MTAP of the black sea fleet of the combined impact of two high-rise (captain V. I. Minakov and Lieutenant Tokarev) and three low-altitude (captain Pavlov and Lieutenant A. R. Kovtun and Alexei) torpedoes sank a tanker of the enemy.
One of the successful pilots of the Northern fleet was G. D. Popovich (76th ARS). At the expense of his crew recorded three transports with a total displacement of 20 thousand tons and a patrol boat. The latest victory, the pilot has won in 1945, sinking a Japanese destroyer. May 11, 1944 the outfit of the six Il-4T 5th MTAP sank the German tanker with a displacement of 6000 tons and damaged a patrol boat off the coast of Northern Norway.
One of the first cases of successful torpedoing in the Baltic sea occurred on 19 October 1942 In the day the crew of captain C. A. Balabina from the 1st MTAP sank the patrol boat. Subsequently, at the expense of his crew recorded three more transport, a gunboat and a destroyer-type Jaguar. In 1943, krakerstva torpedo in the Baltic sea has gone beyond the Gulf of Finland. But, apparently, this year the greatest brunt of the fighting ships of the enemy lay on the lend-lease bombers A-20.
Successfully operated the mine and torpedo aircraft in the sea of Japan. After completing 68 sorties, the crews DB-ZF and Il-4T sunk transports and five destroyer-type “Kamikaze” with a total displacement of 35 tons
DB-ZF — deep modification of the “trucker”
Aviators are still learning new bomber, and in the CDB began its most substantial upgrade. Serious changes were undergone by the airframe, landing gear and fuel system. First of all, the improved aerodynamic shape of the car, changing the nose of the fuselage, increased the wing area while reducing the relative thickness of the profile. Due to the reduction of the ailerons managed to increase the area of the landing flaps, which in combination with the increased angle of deflection reduced landing speed, and mileage. At the same time. through the use of new technological processes, simplify the Assembly as individual units and machine as a whole. Metal fuel tanks replaced the soft with the filling system of neutral gas from the onboard tank.
It was expected that the plane with the engines M-88 can reach speeds of 485 — 500 km/h at 7000 m. However, in practice all turned out differently. On the first machine, by the way, as on TSKB-26, the fuselage made of wood, and engines left the old — M-87B. After the first stage of state tests, which ended in September, the car was returned to the factory for installation of M-88, but the test he did not survive due to defects in the oil system. Had experienced and the first production vehicles to temporarily put M-87В.
In June 1940, on state tests received DB-ZF with new small plants: the upper MV-3 and MV the bottom-2 (instead of the top lukovoy SU and PU). MV-3 provided the best maneuverability of the gun with less effort, and MV-2 optical crank the sight of strengthened the defence against attacks from the fighters from below. Tests showed that maximum speed of the aircraft with retracted MW-3 decreased from 425 to 415 km/h, and when the battle position of the upper installation speed does not exceed 410 km/h Range when flying at an altitude of 4,000 m with a speed of 340 km/h was reduced from 2950 to 3060 km has Deteriorated, and other parameters, but the defenses of the machine increased.
A month later, the state tests have received an advanced DB-3F. In this riveting wing and fuselage performed wpoty. Changed the contours of the front part of the canopy pilot, making them more fluid and improved the styling of the plexiglass nose of the fuselage Crutch has become retractable, which increased the sectors of fire from installation of MV-2.
On engines installed a new hood with a larger output section that provided the best thermal conditions of the engine and the cooler moved to the front edge of the wing. The planes were painted dark green above and below light blue paint.
Torpedo bomber Il-4T
Tests showed that the handling characteristics remained unchanged, However, when the rotation of the upper machine gun setup of MV-2 to the side the plane started to “walk” through the course, creating a roll up to three degrees, easy paronomasia rudder.
Many troubles deliver more “raw” motors M-88, forcing them instead to continue the acquisition of combat vehicles already tested M-87В.
The beginning of the great Patriotic war the main long-range aircraft became DB-ZF (renamed by that time, Il-4). Intended for bombing attacks in the deep rear of the enemy Il-4 from the first days of the war, as, indeed, his predecessor, was brought to deter the advancing Nazi troops, mainly in the daytime. The solution to unusual problems without escort fighters resulted in heavy losses from both flak and enemy fighters.
For example. 22 Jun 70 DB-3F ‘ 96, dbap made its first sortie, the airfield has not returned 22 cars, of which more than half were shot down by the enemy, and the rest made a forced landing at other airfields. After this departure a quarter of the fleet was under repair.
The next day during the attack on the convoy of the enemy in the Cap-the Birch of the nine DB-3F 212, dbap lost eight. 24th June the bombardment of the airfield Vilna of nine cars of ‘ 96, dbap lost five. Such is the price of misuse of military equipment due to the confusion and chaos of the initial phase of the war.
But this was not the only cause of large losses. The first sortie confirmed the ineffectiveness of the top infantry unit of bombers. Moreover, not all aircraft had a machine gun to protect the lower hemisphere. Engineering service long-range aviation had urgently installed on the DB-3 additional firing points and to enter into the fourth crew member — air gunner. But improving one, downgraded another. Increased flying weight of the plane, and the alignment has shifted back, reducing the already inadequate longitudinal stability margin. Even the setting of the lower machine-gun point, not really increased firepower of the aircraft. In December 1941 the head of the 10th government of the Department of the air force Bibikov wrote in NCAP “the Plane DB-3F armed with a ShKAS machine guns, can not reflect the attacks of enemy fighters, armed with heavy machine guns of 12.7 mm and cannons. Please give it to Your plants urgently to install Berezina machine gun caliber 12.7 mm in the turret MV-3”.
First on the list for improvement were 40 cars out of 51 ad (Sasovo) and 42nd ad (Rasskazovo), carried out military work for the special task of the high command.
In 1942, as part of the long-range aviation on DB-ZF set two 650-liter drop tanks and two additional oil tank that increased the range 450 — 480 km. On this sample by may 1942, the factory teams and technical personnel of the regiments converted several hundred combat vehicles.
Exploitation of Il-4 and combat conditions showed a large variation in the fuel consumption due to incorrect adjustment of carburettors, which reduced the range. No flame arresters on the exhaust pipes of engines unmasked planes at night, and the blue colouring on the lower surface of the machine strongly reflected the light from the spotlights. Outdated guns did not provide the required defense in a dogfight.
Twice the Mountain of the Soviet Union A. I. Molodchy said: “the Machine is (Il-4) was already not what it used to be. And, unfortunately, things didn’t change for the better. Many of the parts and assemblies made of substitute materials. One time released from the aircraft with a wooden cabin mate, and this continued up until the cab began to fall off during takeoff and especially during landing. Of course, we understand that evacuated the aviation industry cannot yet give the aircraft the best quality, so was glad — if only to fly…
The autopilot on the aircraft there (on separate machines set Approx. ed.) and by their nature, Il-4 is unstable, every second tries to hit a roll to go off course, to lift up or lower the nose. You need to constantly turn the steering wheel, to run the plane in a given mode… the Il-4 even without bombs a day in good visibility it is not easy to lift into the air. Takeoff was considered one of the most difficult elements of the flight”.
As already noted, the plane was allowed a maximum bomb load of 2,500 kg, but in practice this was rarely used. The rise was very complicated and unsafe, especially in the case of failure of one of engines. Yes, and engines for continuous operation in afterburner was spent pretty quickly, and the new engines lacked. Since the summer of 1942 Il-4 to produce steel with swept consoles that slightly increased the longitudinal stability margin.
Until the end of 1941 engine plant No. 19 issued 412 engine M-82, virtually no business lying in the warehouses. At the same time, the motors M-88 and M-87 was not enough not only to replace obsolete, but for new aircraft. In early 1942, the 126th plant attempted to improve the flight characteristics of the DB-3F by replacing the M-88 is more powerful M-82. This was facilitated by the supply disruptions 88’s engines caused by the evacuation of industry to the East of the country.
Flight tests were conducted on three machines. The first departure on 10 February showed a strong release of motor oil. Debugging dragged on for almost two months, and only on 5 April began testing.
For engines not found standard screws AV-5 and instead had to put the bushing screws VISH-22 with the blades VISH-21 with a diameter of 3.4 m. the Speed-endings of the blades “surrogate” screws reached the sound, which reduced their cravings. Flight characteristics though it turned out lower than estimated but exceeded the similar parameters of production aircraft. When increased to 8850 kg (vs 8033 kg) normal flight weight (mostly due to fuel) the range is increased to 900 km, maximum speed — 45 km/h. Improved takeoff performance and climb rate.
In conclusion, the report mentioned the need to install M-82 in production aircraft. But due to the unsatisfactory work of system of cooling of oil, mismatch wheels, increased chassis loads. the lack of depreciation of engines and the inconvenient location of its units, the aircraft is not recommended for serial production
Besides these, there were other modifications of the aircraft, however, the amount of journal publication does not dwell on them.
Over the years of mass construction of domestic plants produced nearly 6,000 of the DB-3 and Il-4. The production of Il-4 was completed in 1945 with the release of the last four cars at the factory number 126. Production engine M-88B stopped at the end of 1947, but their Assembly of the remaining backlog lasted more than three years. In fact, since 1947, began a write-off of aircraft, which accelerated after the development of the industry of production of the Tu-4. Despite the huge number of built long-range bombers, none of them survived until our days. And stored in museums and erected on pedestals restored from enthusiasts found the remnants of war
N. VASILIEV
On the night of 8 August 1941 from the airfield Cahul, located on the island of Ezel (Saaremaa) in the Baltic sea, flew three groups of 15 bombers DB-ZT of the Baltic fleet. Aboard each plane were eight stokilogrammovye high-explosive bombs. To Berlin had to go through the 1760 km, of which 1400 over the sea at an altitude of 7000 m out of sight of land and the same back. That night in Berlin for the first time over the past two years howled air RAID siren. The Germans, not believing in the capabilities of Soviet aviation, reported on the RAID of British bombers. However, soon the whole world heard the TASS report about the RAID of Soviet aircraft, razveyatsya the myth of the invincibility of Germany.