VI-100

In 1938, the development of the high-altitude fighter VI-100 began. The aircraft was to be equipped with powerful weapons and fly at an altitude of 10,000 m at a speed of 630 km / h. The work was carried out under the leadership of Vladimir Mikhailovich Petlyakov . The prototype fighter made its first flight on December 22, 1939 . The machine was equipped with two M-105 engines, the pilot was located in the front pressurized cabin , and the navigator-bombardier and radio operator gunner were in the rear pressurized cabin. Two ShVAK guns and two ShKAS machine guns were installed in the nose of the fuselage , and a ShKAS machine gun, remotely controlled by a radio operator gunner, was located in the rear. The first prototype “VI-100” could carry two K-76 cartridges in the internal compartment, each of which had 24 artillery shells of a caliber of 76 mm or two K-100 cartridges with 96 bombs weighing 2.5 kg each. For the second prototype “VI-100” (understudy), it was possible to install external holders for two bombs weighing 250 kg or 500 kg.

After completion of factory tests on April 10, 1940, two cars were transferred to state tests at the Air Force Research Institute . During the tests, the second car was in an emergency and received severe damage. Based on the test results of the first aircraft, a conclusion was made about the aircraft's compliance with the requirements of the technical specifications and recommendations were made on how to improve (increase the keel area, change the stabilizer installation angle, etc.) before building a pilot batch of VI-100 aircraft, as well as on creating a VI-100 dive bomber .

Given the need for a quick replacement of the main front-line SB bomber, the command of the Red Army Air Force decided to start serial production in June 1940 on the basis of the VI-100 dive bomber PB, which later received the designation Pe-2 .

In 1935 ÷ 1940 in the USSR, special attention was paid to creating a high-altitude fighter capable of destroying enemy aircraft of any purpose flying at an altitude of up to 10-12 km. The analysis of military operations and the prospects for the development of military aviation, as well as the corresponding calculations, showed that the general tendency to increase the speed and altitude of flight of bombers makes it extremely difficult to intercept them, even with a well-functioning air surveillance, warning and communication service. In particular, the brigade commander P. P. Ionov in his book: “Fighter Aviation” (published in 1940 for the command staff of the Red Army Air Force) summarizing the experience of combat operations of fighters and evaluating the promising areas of development and combat work of this kind of aviation wrote: “ The higher the enemy’s flight height, the farther from the front line he can be intercepted by fighters. And we know that the heights of possible and probable flights of bombers are growing from year to year. We also know that the increase in the speed of transmitting messages about the flight of the enemy and the speed of departure of the fighters lags relatively relative to the increase in the speed of flight of the bombers, in this regard, the bandwidth of tactical surprise increases (that is, the distance from the front to the line of interception of bombers by fighters,) ... the flight altitude of modern military aircraft reaches 9000 ÷ 11000 m single-engine and twin-engine aircraft and up to 8000 m for four-engine. The difference between the “ceilings” of aircraft for various purposes is increasingly decreasing, especially between single-engine and twin-engine. "The combat altitude of aircraft in the coming years may be increased, that is, it will reach the stratosphere (over 11,000 m) ." Thus, the need of the Red Army Air Force for a high-altitude fighter, with the main purpose of carrying out the interception of high-flying high-speed targets, was theoretically justified ... [TsAGI 1994-2 (21)]

By the end of the 1930s. In the Soviet aviation industry, a personnel problem arose due to the acute shortage of repressed qualified designers. Therefore, on the initiative of L.P. Beria, in Moscow, a design institution was urgently formed in the NKVD system of the USSR - the "Special Technical Department" (STO) of the "closed type", which was supposed to form the Central Design Bureau Aviation - TsKB-29 , which was to combine several independent design bureaus for the design of promising combat aircraft. The main staff of TsKB-29 was supposed to be recruited from among the arrested "enemies of the people." The building of the former KOSOS TsARI was determined as the location of TsKB-29.

The organization in the USSR of such institutions, using convicted specialists for scientific and design work, has been practiced since the late 1920s, with the involvement of specialists in various sectors of the economy arrested in the "Industrial Party" case. In particular, a design bureau was formed from the composition of aviation industry workers at plant No. 39, in which the I-5 fighter was designed in record time.

In the summer of 1938, V. M. Petlyakov, who was arrested at the beginning of November 1937, was charged with the following: - " wrecking delay in finalizing the heavy bomber ANT-42 " - they unexpectedly offered to return to design work in the Special Technical Department (STO) of the NKVD.

In the middle of 1938 , immediately after the formation of a team of designers and engineers (50 specialists in total), under the leadership of V.M. Petlyakov , in a special design bureau of the NKVD ( SKB-29 ), they began to develop a high-altitude fighter with a long flight range and powerful weapons, under the symbol " 100 ". ^{[1] [2]} .

Almost simultaneously, besides the Design Bureau of V.M. Petlyakov - the prison department of the STO NKVD, the task for the development of a high-altitude fighter (VI) was issued by the Design Bureau: A.I. Mikoyan and M.Gurevich, P.O. Sukhoi, A. S Yakovlev and Polikarpov. For successful VI design, all involved design bureaus were provided with all the necessary arsenal of available funds. By this time, several types of high-altitude motors were completed in the USSR and their development tests were carried out, in particular: AM-35A with a single-speed supercharger equipped with rotary blades, M-105 with turbochargers TK-2 and M-105PD with a two-stage supercharger developed by V A. Dollezhal. [TsAGI_1994-2 (21)]

In accordance with the developed tactical and technical requirements, the terms of reference for the design of the VI determined: practical ceiling of 12500 m; maximum flight speed at an altitude of 10,000 m - 630 km / h; range from 1400 km in the normal version, up to 2400 km in the reload version. The aircraft was to be equipped with powerful and effective offensive and defensive weapons. It was believed that a VI designed to intercept enemy bombers should be made multi-seat, since it is difficult for a single-seat car pilot in an aerial battle with bombers flying at high altitude to simultaneously control the aircraft, shoot, monitor the air situation and maintain radio communications. In addition, for the successful interception of high-altitude targets, the fighter required not only high speed, but also an increased radius of action, which made it possible to expand the intercept range and carry it out already at distant approaches to the guarded object. The main feature of the development of a fighter with a large design altitude was associated with the solution to the problem of ensuring the required power of the VMU at high altitudes. [TsAGI_1994-2 (21)]

During the design process for the “VI-100,” the aerodynamic configuration of the airframe, which was very common at that time, was adopted — a free-standing twin-engine monoplane with two keel tail units, a three-leg landing gear with a tail wheel retractable in flight. The paramount importance was attached to ensuring high performance aerodynamic and weight perfection of the aircraft. The smoothness of the contours of the parts of the airframe was combined with the minimum possible number of structural elements protruding into the stream. To reduce aerodynamic drag, the water radiators of the engine cooling system were “recessed” in the wing, and the oil radiators of the engines were arranged in the lower tunnels of the engine nacelles. Safe performance of all aerobatics was ensured by a tenfold safety margin of all-metal glider parts. The number and type of motors are determined taking into account the requirements for maximum speed, altitude and payload. For the power plant, the “ M-105 ” engines, the latest in those times, with VISH-42 propellers were selected, each motor is equipped with two TK-2 turbocompressors installed along the sides of the engine nacelles and included in their structural power scheme. Weight and dimensions of the machine (wing area 40.7 m ² , normal take-off weight - 7200 kgf, reloading - 8000 kgf). For the first time in the practice of Soviet aircraft construction, two fuselage pressurized cabs (GK) were equipped. The wing was composed of high-speed aerodynamic profiles such as TsAGI “B” and “BS”, which, in comparison with other profiles — at small angles of attack had the highest critical Mach numbers (in order to reduce the influence of wave drag), and created significantly lower aerodynamic torques. This allowed to significantly reduce the weight of the wing structure, while ensuring its strength. A similar aerodynamic layout of the tail unit - significantly facilitated the construction of the tail of the fuselage, perceiving forces from the tail. The used aerodynamic profiles for bearing surfaces contributed to: a significant reduction in the mass of the structure, achievement of a high maximum horizontal flight speed, high dive speed with good stability in this flight mode. But the selected aerodynamic profiles had a low bearing capacity, which significantly reduced the maneuverability and takeoff and landing characteristics of the machine. The fuselage - developed under the guidance of A. I. Putilov - had a streamlined, cigar-shaped, round cross-section. Technologically, it consisted of three mating units (sections). According to its structural and power scheme, each section was close to the “monocoque” type - with a working, relatively thick (1.5–2 mm) skin. The main longitudinal power elements of each fuselage section were four spars at the ends of which butt assemblies were installed. Stringers to reinforce the casing were used very limitedly. The frames were arranged with a relatively large step - 0.3–0.5 m. For the first time in the practice of Soviet aircraft construction, the fuselage was equipped with pressurized cabins. The bow and stern HA were included in the power schemes of the design of the bow and tail sections of the fuselage. To reduce the aerodynamic drag, the pilot’s nose GL was mated with the navigator’s lump GL and the shooter by means of a light (not power) fairing (gargrot). The layout of the aircraft "100" was performed at a very high aerodynamic level, which was noted by military experts. At altitudes up to 10 km, a pressure corresponding to an altitude of 3.7 km was maintained in the main crew, which increased the crew’s performance during long flights at high altitudes. The cabins provided a relatively good overview. In the front of the main aircraft there was a pilot (pilot-crew commander), in the rear - a navigator-bombardier (had duplicated control of the aircraft) and a gunner-radio operator. In the bow of the fuselage, in front of the main gun was a small-gun battery (two ShKAS machine guns and two ShVAK guns ). In the rear part of the fuselage, the layout of a defensive rifle installation (1-machine gun ShKAS) was provided - remotely controlled by a radio operator-gunner (this firing point was established during flight tests). In the central part of the fuselage, a cargo compartment was made to accommodate bomber weapons designed to destroy air and ground targets, consisting of: two cartridges containing 24 76-mm artillery shells in each (the height of the detonation of shells was set on the ground before the flight), or 96 2.5 kg bombs. The use of fighter artillery shells, grenades or fragmentation bombs against the formation of bombers was then considered a promising area in the development of aviation weapons. In Italy, tests of this type of weapon were conducted. For the first time in Soviet aircraft manufacturing practice, electromechanisms were widely used, which was considered very promising. [TsAGI_1994-2 (23)]

The fuselage - developed under the guidance of A. I. Putilov - had a streamlined, cigar-shaped, round cross-section. Technologically, it consisted of three mating units (sections). According to its structural and power scheme, each section was close to the “monocoque” type - with a working, relatively thick (1.5–2 mm) skin. The main longitudinal power elements of each fuselage section were four spars at the ends of which butt assemblies were installed. Stringers to reinforce the casing were used very limitedly. The frames were arranged with a relatively large step - 0.3–0.5 m. The bow and stern pressure cabs were included in the power schemes of the design of the bow and tail sections of the fuselage. To reduce aerodynamic drag, the pilot’s nasal pressurized cabin was interfaced with the navigator’s lumped pressurized cabin and the shooter by means of a light (not power) fairing (gargrot).

For the first time in the practice of Soviet aircraft construction, two GKs were included in the power scheme of the fuselage structure.

The crew members' working capacity was enhanced by the equipment of two pressurized cabs (lead developer - M.N. Petrov), supplied with compressed air from turbochargers, and providing constant pressure in the cockpit, starting from a height of 3700 m and up to a ceiling of 10,000 m.

The wing is formed by a center-wing rectangular in plan and two detachable consoles, trapezoidal in plan, having a very small sweep angle along the leading edge, according to the structural power scheme - a two-spar one, with a frequent set of stringers and ribs, with a lining thickness of 0.6 ÷ 0.8 mm. The ailerons are made split, the flap flaps are of the Schrenk type.

The chassis was designed under the leadership of T.P. Saprykin - a three-leg with a tail wheel. The main landing gear supports are two-post, retractable into the engine nacelles by turning back. Tail support landing gear - retracted into the fuselage.

On the VI, for the first time in the practice of Soviet aircraft construction, electro-remote control units, leading developers L. A. Yengnaryan and I. M. Sklyansky, were widely used.

As part of a powerful onboard offensive armament, it is planned to install in the bow of the fuselage: two 20-mm ShVAK aviation cannons (ammunition - 300 rounds per barrel) and two ShKAS 7.62-mm machine guns (900 rounds ammunition per barrel). To protect the rear hemisphere, it was planned to install one stationary ShKAS machine gun in tail coca with an ammunition of 700 rounds.

In the cargo fuselage compartment, the suspension of a new type of weapon was initially envisaged - the K-76 projectile cartridge (ammunition - 40 three-inch artillery (non-feathered) shells), for dropping shells on the enemy aircraft. The shells were detonated using a remote tube. In a later version, the suspension of the K-100 cartridge was envisaged (ammunition - 96 bombs of 2.5 kg caliber). At that time, bomber weapons for hitting air targets were considered quite promising.

To use the VI as a dive bomber, it was possible to suspend two external bombs of 250 kg or 500 kg caliber on the external holders.

All design documentation went beyond the bounds of the OTB, signed by its head (State Security Major V. Kravchenko), direct developers and leading specialists, instead of personal signatures, put their number stamps on the documents.

The established tight deadlines for the design of the VI determined the beginning of its flight tests in 1939, taking into account the extremely intense mode of operation in the OTB system: 11-12 hours a day, without days off, without any exemptions.

At the beginning of 1939, V. Petlyakov’s brigade was transferred to the building of TsOSI COSOS on ul. Radio, where she started the shop work.

At the final stage of the design of the VI-100, military experts began to pay more and more attention to the possibility of using it as a dive bomber, the need for which at that time was felt more and more urgently. As a dive bomber, additional requirements were put forward for the “VI-100”: with a take-off weight of about 9,200 kg, carry up to 1,000 kg of bombs on external suspensions and hit ground targets with dive with high accuracy. In this regard, for the use of “VI-100” as a dive bomber, the possibility of external underwing suspension of two bombs was provided, in versions: 2 × 100 or 2 × 250, or 2 × 500 kg. Soon, the components of the purpose of the “100” aircraft (high-altitude fighter and dive bomber) began to be regarded as equivalent. [Shavrov_1988 (165,166)]

In May 1939, a full-scale model of “VI-100” was presented to the commission under the chairmanship of the head of the Air Force Research Institute, Major General of Aviation A. I. Filin. Military experts noted a deep study of the main issues of the tactical and technical requirements for the aircraft, in the conditions of not quite formed ideas about the nature of the future war and the conditions for the use of high-altitude fighter and dive bomber.

In July 1939, the mock commission, with minor comments, approved the VI-100 mockup, after which the production of the prototype and its understudy began.

In 1939, the Design Bureau of V. M. Petlyakov, earlier than the other Design Bureau, completed the detailed design of the high-altitude fighter "VI-100", which was the first Soviet multi-purpose combat aircraft (high-altitude fighter and dive bomber), with pressurized cabins. The construction of two copies (the first prototype and its “understudy”) was carried out at the Moscow plant number 156

At the end of 1939, the Soviet delegation of military specialists got acquainted with the latest German air force combat aircraft, which did not include large formations of long-range high-altitude high-speed bombers. At the beginning of World War II, this was confirmed during the combat use of German aircraft in Poland and France. On this basis, at the level of the military leadership of the USSR, it was concluded that the need for the Red Army Air Force in the specialized high-altitude fighter "VI-100" is relatively low - the development of high-altitude fighters I-26 and I-301 were stopped. At the same time, the demand for a mass, high-speed, front-line diving bomber has sharply increased. [TsAGI_1994-2 (24)]

December 22, 1939 . At the LII aerodrome in Zhukovsky, test pilot P. M. Stefanovsky first took off the first prototype of the “VI-100” and launched the factory test program of the aircraft in the form of a high-altitude fighter. The first prototype “VI-100” could carry two K-76 cartridges in the internal compartment, each of which had 24 artillery shells of a caliber of 76 mm or two K-100 cartridges with 96 bombs weighing 2.5 kg each, and also an external suspension of a bomb load weighing up to 1000 kg.

Constructive innovations entailed a lot of defects discovered during testing: in the first flight, a structural defect of the shock absorbers of the landing gears appeared - having discovered the errors in the calculations, it was quickly eliminated; finalization of the power plant was required: at altitudes above 5000 m, the performance of the oil cooling system was insufficient; starting from a height of 6000 m, the water temperature in the engine water cooling system exceeded the maximum allowable. During the flight factory tests of “VI-100”, the engines, oil pumps and other equipment were replaced twice, but it was not possible to realize the specified altitude and speed characteristics, including the rate of climb at high altitudes: at the “run of the site” at an altitude of 6600 m, the highest speed reached - 538 km / h; a machine with a normal flight weight of 7265 kg gained a height of 1000 m in 6.8 minutes.

During the period of factory tests from December 22, 1939 to April 10, 1940, for 122 days the “VI-100” was under repair and completion (after an emergency landing “on the stomach” due to the non-release of the ski chassis) and for 11 flying days, completed a total of 23 flights.

In the spring of 1940, tests began on the second prototype - the VI-100 understudy, which was slightly different from the first prototype ... As on the first prototype, the understudy provided for the possibility of installing two wing supports for the external suspension of two bombs weighing 250 kg or 500 kg each. (the maximum mass of the external bomb load is up to 1000 kg), but in the fuselage cargo compartment, instead of cartridges, an internal suspension of the bomb load weighing up to 600 kg is provided. [Shavrov_1988 (165,166)]

On April 10, 1940, after completion of the factory tests, two VI-100 prototypes were transferred to state tests at the Air Force Research Institute .

On April 11, 1940, the first experimental “VI-100” passed state tests at the Air Force Research Institute of the Red Army, the crew was tested by a crew consisting of: Major Major Stefanovsky and navigator Major Nikitin.

The second experimental “VI-100” - “understudy”, according to the program of state tests, was tested by captain A. M. Khrinkov and navigator P. I. Perevalov. The “understudy” was slightly different from the first instance: in addition to cartridges, an internal suspension of air bombs of 25 ÷ 100 kg caliber was provided.

In the 11th flight, due to a violation of the tightness of the gas system (gasoline getting into the pressurization supercharging line) and sparking of the switch contacts, a fire broke out in the pilot's cabin ... Blinded by smoke A. Khrinkov was forced to make an emergency landing, exceeding the vertical speed - the car Kapotiruyu and received significant damage, the crew was injured ...

According to the results of tests of the first aircraft, taking into account the positive feedback from test pilots, a conclusion was made on the compliance of the aircraft with the requirements of the technical specifications and recommendations were made on how to refine (increase the keel area, change the angle of the stabilizer , etc.) before constructing a pilot batch of VI-100 aircraft, as well as recommendations on the creation of a dive bomber based on the VI-100. They didn’t have time to complete the fully state flight tests of the VI-100 ...

State tests were continued at the first experimental “VI-100” after its refinement: to increase the directional stability, the area of ​​vertical plumage was increased by about a third of the area (from 0.77 to 1 m ² ). The longitudinal stability characteristics of the machine were considered unsatisfactory, and to improve them, it was recommended to increase the sweep angle along the leading edge of the wing consoles, which was subsequently implemented on the PB-100 (Pe-2). With the landing flaps fully extended, it was impossible to land the “VI-100” at “three points” - there were not enough rudders, so it was prescribed to partially release the flaps at the landing, and it was recommended to change the stabilizer angle for serial machines.

The wing surface, formed by a set of high-speed, pointed-nosed aerodynamic profiles of type TsAGI “B” in airborne and type TsAGI “VS” in end sections, had minimal aerodynamic drag at high flight speeds close to maximum, but at low speeds and angles of attack close to landing - the machine became very "strict" in control - with roll and glide - an asymmetric flow stall developed sharply on the wing surface, with a tendency to stall the machine onto the wing. The high-speed aerodynamic profiles implemented in the aerodynamic configuration of the wing, at high flight speeds and corresponding small angles of attack, compared with non-high-speed profiles, had similar lift coefficients, with significantly lower aerodynamic drag coefficients - providing a significant reduction in wing drag at large speeds and their corresponding small angles of attack. But at large angles of attack and low speeds that correspond to the conditions of landing the plane, when the pilot creates a certain roll and glides with an asymmetrical flow around the wing — a set of high-speed profiles on the wing surface — an asymmetric flow stall developed sharply, leading to an additional dangerous heeling moment . The mechanization of the trailing edge of the wing — takeoff and landing flaps — like Schrenk in the fully extended position — did not allow the pilot to land the “VI-100”, at “three points” —the elevator did not have enough travel to compensate for the arising diving moment, therefore it was prescribed when landing, release the flaps in an intermediate position, and for serial cars it is recommended to change the angle of the stabilizer.

During state tests, 34 flights were completed, the total flight time was 13 hours 25 minutes. In general, the aircraft, taking into account the identified shortcomings - met all the requirements of the technical specifications with the exception of the maximum speed requirement. At different altitudes, the speed shortfall was 10–20 km / h. The general conclusion on testing the aircraft "100" was favorable, in particular, it was noted:

" 1. Aircraft" 100 "is the most successful solution to the problem of creating an armed vehicle with a sealed cabin. It is necessary to build a pilot series of aircraft" 100 " ...

“ 3. In order to use the high aerodynamics of the“ 100 ”aircraft, it is advisable to create a dive bomber on its base without a pressure cockpit. It is necessary to build an experimental series. Present the model of this aircraft for approval by June 1, 1940 ... "

By this time, the leadership of the USSR aviation industry was tasked with the urgent replacement of the outdated main front-line bomber of the Red Army Air Force - SB, with a new generation diving bomber. As a result, in the test report "VI-100", the head of the Red Army Air Force 2nd rank commander Y. Smushkevich wrote: " The act is approved as amended by the conclusion: the aircraft" 100 "in the dive version is recognized as expedient for serial construction ."

On May 1, 1940, the VI-100 participated in the air part of the parade on Red Square, its creators watched it while on the roof of the Kosos TsAGI building - their then prison. By mistake, P. Stefanovsky forgot to remove the chassis, but fortunately for everyone it was "worth it."

At the end of May 1940, Petlyakov, who pleaded guilty during interrogations in Butyrka at the end of 1937, was sentenced: 10 years in camps, 5 years of defeat in rights and complete confiscation of property.

At the end of May 1940, V. M. Petlyakov was entrusted with an urgent task - for a month and a half - to remake the “VI-100” as a variant of the three-seater high-speed dive bomber “PB-100”, without a main gun and a military missile, with powerful defensive weapons, with speed 550 km / h at an altitude of 5 km. An extremely tight deadline was determined - in September 1940, the PB-100 was to be submitted for state tests. In this regard, the VI-100 state test execution program was interrupted ... Initially, it was planned to release a military series of 10-15 vehicles, but subsequently they did not return to the issue of mass production of the VI-100. [TsAGI_1994-2 (24)]

On June 4, 1940, it was decided to “re-profile” the high-altitude fighter into a dive bomber, and only 1.5 months were allotted to the drawings for the new aircraft.

Since July 1940, Petlyakov’s OKB operating in the OTB system has completely switched to developing a machine in the form of a front-line, high-speed diving bomber under the designation “PB-100”, which received the Pe-2 military designation in serial production, and actually inherited from its predecessor "VI-100" flight tactical characteristics of the fighter. [Shavrov_1988 (164,165,166)] [TsAGI_1994-2 (21)]

Data Source: ^[3]

Specifications

• Crew : 3 people
• Length : 12.69 m
• Wing span : 17.15 m
• Height : 3.95 m
• Wing Area: 40.50 m²
• Empty weight: 5172 kg
• Normal take-off weight: 7260 kg
• Powerplant : 2 × PD M-105 with TK-2
• Engine power: 2 × 1100 l. with.

Flight characteristics

• Maximum speed:
  • At the ground: 455 km / h
  • At an altitude of 6000m: 535 km / h
• Practical range: 1,400 km
• Practical ceiling : 12,200 m
• Rate of climb : 588 m / min

Armament

• Shooting and cannon: two 20 mm ShVAK guns and two 7.62 mm ShKAS machine guns
• Bombs : 1000 kg

• V. B. Shavrov. The history of aircraft designs in the USSR. 1938 ÷ 1950 2nd edition, revised, Moscow, Mechanical Engineering. 1988, pp. 168 ÷ 174. [Shavrov_1988 (168 ÷ 174)]
• Aircraft manufacturing in the USSR 1917 ÷ 1945 Book 2. Publishing house of TsAGI department, 1994 p. 21, 53 ÷ 56. [TsAGI_1994-2 (21, 53 ÷ 56)]

• Ivanov, S.V. Pe-2 // War in the Air. - M .: LLC "ARS", 2004. - No. 113.
• Kotelnikov, V. R. Diving Pe-2 bomber / V. R. Kotelnikov, A. N. Medved, D. B. Khazanov // Aviation and astronautics yesterday, today, tomorrow: Popular Science magazine. - 2004. - No. 5-6.