Aviation of World War II
High Speed Bomber
Pe-2I is an experienced two-seater daytime dive bomber. The official tactical and technical requirements of the Air Force for a high-speed dive bomber for 1944 provided for a bomb load of up to 2500 kg with its flight range of up to 1500 km and "the possibility of performing a combat mission by groups of bombers in the absence of fighter cover in the face of active opposition from enemy fighters". The most striking representative of this trend was the British Mosquito bomber, which was generally devoid of defensive weapons. However, Myasishchev, foreseeing the negative attitude of the leadership of the Soviet Air Force to the idea of an unarmed bomber, did not dare to completely abandon defensive weapons. In this regard, Vladimir Mikhailovich decided to leave two firing installations on the new version of the dive bomber: fixed by the pilot and the navigator, remotely controlled in the tail cock of the aircraft. Fortunately, many years of work on the DEU (remote electrified installation) were coming to an end.
Structurally, the Pe-2I was a cantilever all-metal monoplane with a mid-wing location, the area of which was increased by 1.2 m² (mainly due to sagging in the front of the center section). The design of the detachable wing parts did not differ much from the serially produced ones and did not require serious alterations of stands and technological equipment. VK-107A engines were installed in the nacelles, developing a power of 1500hp. from. at an altitude of 4500 m. Compared to the Pe-2F, the motors were displaced forward by 200 mm. The propellers were three-bladed, of the VISH-107TL5 type, with a diameter of 3.1 m. Individual exhaust pipes of the motors were placed in four rows - two rows on top and one on the side surfaces of the hoods. Fifteen fuel tanks held a maximum of 1844 liters of fuel, which increased the practical range to 2275 km. The shift of the wing of the new profile to the middle position and the increase in the fuselage (by 1 m in length and by 300 mm in width) made it possible to place the FAB-1000M43 in the bomb bay (with a trimmed stabilizer). The landing gear of the aircraft was made according to the Pe-2 type, but with the same wheel dimensions, the struts of the main landing gear were reinforced taking into account the increased take-off weight.
The stabilizer, as well as on ordinary "pawns", was carried out mobile. Experimental Pe-2I did not have braking grids and a dive machine. Fifteen fuel tanks held a maximum of 1,844 kg of fuel and were located in the center section, consoles, the middle of the fuselage and engine nacelles. All tanks were sealed. Oil tanks with a capacity of 160 liters were located in the engine nacelles. Water radiators were mounted in the nose of the center section, while oil coolers and suction pipes were mounted in the nose of the consoles. Unlike the serial Pe-2, the air outlet from the radiator tunnels was carried out downward, under the wing. At the exit from the tunnels, electromechanically controlled dampers were installed, which ensured effective regulation of the water temperature (the blinds on the serial "pawns" did not work well). The aircraft had a neutral gas system.
The aircraft crew consisted of two people - a pilot and a navigator. The well-shaped cockpit canopy provided the pilot with a comfortable landing and excellent visibility. The fixed UB-20 cannon (on the prototypes, the 12.7 mm UBK machine gun was retained instead of it) was placed under the pilot's seat, which excluded his glare during night shooting - the flame from the shots covered the nose of the aircraft. The remotely controlled UBK machine gun was installed in the tail spinner and provided firing angles upwards - 18°, downwards - 12° and left-right - 16 ° each. Its cartridge box held a tape with 100 rounds. The electromechanical system provided tracking by the machine gun barrel of the sighting line. Although the firing angles of the mobile unit were relatively small, given the high speed of the bomber, they were calculated to provide satisfactory rear protection. When catching up, an enemy fighter could line up for an attack in a relatively small corner sector. However, military experts were skeptical about the estimated estimates and preferred to wait for the results of air battles with captured German fighters.
Protection of the aircraft crew from enemy fire included an armored backrest, a headrest and an armored pilot's seat, as well as two vertical plates that covered the navigator, that is, it did not radically differ from that used on the serial Pe-2. Additional defensive capabilities were provided by two DAG-10 aircraft grenade holders, which proved their effectiveness at the front.
Pe-2I, second experienced
At the end of May 1944, the State Defense Committee adopted decree No. 5947, according to which the plant No. 22 was instructed to produce a small series (5 vehicles) Pe-2I by October 15, 1944. However, this decree was not fulfilled. The main reasons were, firstly, the reluctance of the leadership of the NKAP and the plant to reduce the volume of production of conventional Pe-2 and, secondly, the difficulties in mastering the serial production of VK-107A engines, which were primarily intended for Yak-9U fighters.
In January 1944, by order of the NKAP No. 22, the construction of the third copy of the Pe-2I in the version of a heavy fighter was ordered. The use of very powerful offensive weapons was envisaged: it was planned to install two NS-45 cannons in the ventral battery with a stock of 45 rounds per barrel. In November 1944, a cannon carriage and a stand for debugging the entire installation were manufactured and sent to Moscow to plant number 482. The chief designer decided not to build a third prototype aircraft, but to mount a battery on the lead serial Pe-2I. However, immediately after its manufacture, this machine became the object of the picky attention of the military representatives of plant number 22, who revealed a lot of defects on it and demanded their elimination. None of the released Pe-2Is was brought to a combat readiness state until June 1945 and was not paid for by the Air Force, so all further work on the fighter version gradually came to a standstill.
OKO - Opytnyy konstruktorskiy otdel - Experienced design department
NKAP - Narodnyy komissariat aviatsionnoy promyshlennosti - People's Commissariat of Aviation Industry
DEU - Distantsionnaya elektrifitsirovannaya ustanovka - Remote electrified installation
VISH - Vint izmenyayemogo shaga - Variable pitch screw
Pawn - Peshka - Nickname of Pe-2 in VVS
Marshal Novikov's instruction about the need to strengthen the defensive armament of the new bomber forced the specialists of the Air Force Research Institute to revise its concept in accordance with the wishes of the Air Force leadership. As a result, a new version of the bomber appeared, which received the designation Pe-2M. Unlike the Pe-2I, it again became a three-seater, with a gunner-radio operator located in the rear fuselage, and armament, according to the scheme, repeating the usual "pawns". The DEU, which did not live up to expectations, was liquidated, and in return for it, a VU-5-20 mobile installation with a UB-20 cannon and an ammunition load of 200 rounds was mounted in the back of the navigator's cab. The gunner-radio operator also received a UB-20 cannon with 200 rounds on a LUS-20 hatch mount. Both turrets had an electromechanical drive, which made it easier to aim the weapon at the target, since it was very difficult to manually operate a three-pound installation (recall also about the oncoming air flow, which creates a fair amount of resistance). The third UB-20 cannon with 120 rounds of ammunition was placed motionless under the pilot's seat, like in serial Pe-2I. The normal bomb load of the aircraft increased to 1000 kg. To place the "uncut" FAB-1000 M43 bomb on the internal suspension, it was necessary, for the umpteenth time, to slightly increase the dimensions of the cargo compartment.
In terms of the complex of flight performance, the Pe-2M was noticeably ahead of the serial "pawns", although it lagged behind the Pe-2I. The reinforced defensive armament of the aircraft removed the main remark of the customers. At the same time, the leadership of the NKAP and the chief designer of OKO-22 believed that the changes made were not so fundamental and did not require state testing of a new version of the machine. Therefore, the second series of "super pawns" at factory No. 22 was laid down already in February 1945, taking the Pe-2M project as a prototype. However, the prospects for the deployment of mass production of this option soon faded noticeably. With great difficulties, by June 1945, the Kazan plant was able to build only 4 machines. The war in the West is over, the requirements for the quality of aviation equipment began to rise steadily. In this regard, the lead serial Pe-2M aircraft (plant No. 1/1002) was transferred to the Air Force Research Institute for state tests with the participation of specialists assigned to the "pawns": lead engineer lieutenant colonel Gribakin and lead pilot lieutenant colonel Khripkov.
During the tests, Khripkov received a maximum speed of 630 km / h at the second altitude limit. The time to climb 5000 m increased by 1.8 minutes compared to the Pe-2I, and the flight range decreased by 225 km. Such was the payment for enhanced defensive weapons. By the way, Jeffrey De Havilland and his “right hand” Walker estimated the loss of speed of the Mosquito V.IV in the case of the introduction of mobile shooting installations of the order of 48 km / h, twice the amount paid by the designers of OKO-22.
In connection with the introduction of a third crew member, an increase in the mass of armor and weapons, the Pe-2M turned out to be noticeably heavier than its predecessor and ceased to meet strength standards for a number of indicators. The landing gear and wheels no longer "held" the twelve-ton machine. It became more difficult to leave the aircraft in the air, since the installation of the VU-5-20 seriously interfered with the reset of the lantern. Defects in the VK-107A engines continued to annoy. They worked out 47-54 hours in the air, after which they began to "shoot with connecting rods" with enviable regularity. Leaks in water and oil coolers, as well as various seals, were considered almost normal. Other failures were noted, including those of new mobile weapons installations. Mechanized gun mounts turned out to be heavy, inert and poorly controlled. By the end of the state tests of the Pe-2M, "at the very top" a fundamental decision had already been made to stop the production of all variants of "pawns". Therefore, the conclusion of the test report was evasive:
"1. The daytime bomber Pe-2M with 2VK-107A presented for state tests meets the modern requirements for this type of aircraft according to flight performance data ... 5. Due to the large number of defects identified during the tests and listed in the conclusions of this act, the aircraft did not pass the test and is subject to return to the chief designer Comrade Myasishchev V.M. for fine-tuning and elimination of defects ... "
None of the four Pe-2Ms built was ever adopted by the Air Force. All these machines were subsequently transferred to factories No. 26 and no. 482 for experimental work.
High Altitude Fighter
A. Putilov, the chief designer of the aircraft factory No. 22 for the Pe-2 aircraft, was an enthusiastic person. He perfectly remembered that the "pawn" was originally created as a high-altitude fighter, and decided to bring it in this version to mass production. Formally, no one canceled such a task: after all, back in 1941, the Council of People's Commissars ordered the Petlyakov Design Bureau to produce five Pe-2s in the version of a high-altitude fighter with pressurized cabins and transfer them to state and military tests. However, the introduction of a bomber modification at four factories (a fifth was also planned, in Kharkov), and then the war confused all the cards.
Only in the second half of 1942. Putilov, who replaced Isakson as chief designer (Petlyakov, as is known, died in a crash in January 1942), was able to start implementing old ideas again. In December 1942, OKB-22 received an official "go-ahead" from the NKAP for the construction of a high-altitude twin-engine fighter. The deadlines, as always in the war, were very tight: the first flight was planned for the end of February next year.
At the end of January 1943, a model of the Pe-2VI fighter with M-105PD engines (superchargers by V.A. Dollezhal) was presented to the commission of the Air Force Research Institute. Actually, she was shown a mock-up of a pressurized cabin (single-seat, only for the pilot), a propeller group with an M-105PD on an experimental Pe-2 (serial number 12/138), a remotely controlled defensive installation DEU-1 with a UBK machine gun, an almost finished airframe of the Pe-2 aircraft -2VI without motors, as well as drawings and diagrams. The wing area of the aircraft was going to be increased by 2.5 sq.m in the future. The commission approved the layout, making a number of minor changes.
By May 1943, after overcoming numerous discrepancies and difficulties, the Pe-2VI (serial number 15/161) was ready to fly. It should be noted that by this time the M-105PD engines could not be brought up, so they often failed and did not provide the required altitude. Putilov decided to equip the second copy of the machine with another version of the power plant - M-82NV engines with TK-3 turbochargers. The design bureau already had experience in creating a Pe-2 with these engines: the day before, an experimental aircraft of the head. number 19/31.
In the first flights of the Pe-2VI with the M-105PD, defects in the pressurized cabin were revealed, in which the temperature quickly increased and the windows fogged up already on taxiing. However, Putilov hoped to quickly cope with the shortcomings, but for now he reported "upstairs": a high-altitude fighter, created on the basis of the Pe-2, was already flying. The result of the report was stunning.
At that time, the fleet aviation was in great need of a long-range twin-engine fighter to cover the northern convoys, light forces operations in the Black Sea, etc. Six months after the production of the Pe-3bis ceased production, the reconnaissance regiments of the KA Air Force also needed to be replenished, since the serial version of the Pe-2 "scout" was inferior to the "troika" in terms of flight range. As always, the planes were needed "yesterday". Therefore, on May 28, 1943, the GKO, by its decree, ordered Plant No. 22 to start serial production of ... Pe-3 fighters from next month. No pressurized cabins, no remote-controlled machine guns, no Dollezhal superchargers: use only mass-produced motors and equipment. Having familiarized himself in detail with the tactical and technical requirements, Putilov realized that he was actually ordered to organize the construction of the Pe-2I of the 1941 model, but with the M-105PF engines.
It was ordered to remove the machine gun and the armor of the gunner-radio operator from the serial Pe-2, placing a 500-liter fuel tank in the vacant place. In place of the bomb bay, two ShVAK cannons with 160 rounds per barrel should have been mounted. The UBK machine gun with 150 rounds remained in the nose fairing, while the ShKAS had to be placed in the tail.
And then Putilov allowed himself to disagree with the task. He believed that in the form in which the fighter was ordered, he no longer met the requirements of the time (note that the Air Force ordering department, formulating the requirements for a twin-engine fighter for 1943, wanted to get a much more modern aircraft with a maximum speed of 650 km / h, flight range of at least 2000 km and armament, which included two guns of 23 mm (or 37 mm) caliber and three to five heavy machine guns). According to the chief designer, one should have relied on the Pe-2VI, and not at all on the outdated Pe-3.
But he underestimated the consequences of his move. The people's commissariat had a big "tooth" on Putilov: in the course of serial production, the flight performance of the Pe-2 generally deteriorated due to an increase in flight weight and a decrease in the quality of production performance. So, the maximum speed of the "pawns" of some series in 1943 decreased to 480-490 km / h. Despite the tremendous work done, the plane could not be forced to fly on one engine without descending, although in the hands of experienced test pilots a brand new machine, just off the assembly line, still kept "on the horizon", and even then at an altitude of no more than 1000 m. Patched combat aircraft, with engines that had worked for 40-50 hours, often overhauled, could no longer do this. And then Putilov with his "high-altitude" and a dissenting opinion ...
The patience of the leadership of the NKAP ran out, and a new chief designer for the Pe-2 aircraft V.M. Myasishchev. Having familiarized himself with the state of affairs, he, in essence, supported Putilov's point of view regarding the inexpediency of restoring Pe-3 production. However, he reacted with coolness to the "high-altitude" of his predecessor, transferring the work of fine-tuning the Pe-2VI to the LII, and later to the aircraft engine plant No. 26, where it safely "died out" by the end of the year. Soon, instead of the Pe-3, the plant received the task of launching mass production of the Pe-2 with M-82 engines. But this decision turned out to be not entirely justified: after the production of a small series of machines, which were distinguished by an abundance of defects in the propeller group, the plant stopped their construction in the fall of 1943. And then the question of the Pe-3 again surfaced ... Myasishchev could no longer object - he had this time, too, was "a stigma in a cannon."