Heavy Fighter First flight: 1943 Ilyushin

In accordance with the concept of the successful use of the Il-2 as a fighter for transport and bomber aircraft of the Luftwaffe, in May 1943 a decision was made to build a fighter version of the Il-2 attack aircraft. In the Resolution of the GKOK No. 3336 of May 17, 1943, it was indicated that: "To combat enemy bombers and fighters, it is necessary to turn part of the Il-2 aircraft into fighters with a limited dive speed, for which to reduce the flight weight of the Il-2 by removing bomb load, PC, ShKAS machine guns, to transform it from a two-seater to a single-seater and improve its aerodynamic properties ... "

Fulfilling the decision of the State Defense Committee, SV Ilyushin already in July 1943 presented for state tests a modified Il-2I aircraft in the version of a bomber fighter. It was a single-seat Il-2 aircraft with an AM-38F engine, converted from a conventional serial two-seat attack aircraft. Its wing was reinforced by changing the cutting of the wood sheathing sheets, increasing the area of ​​their gluing and riveting the sheathing to the upper flanges of the side members. ShKAS machine guns, bomber armament of internal bomb compartments and attachments to the wing of the launching beams of rocket projectiles were removed from the Il-2I aircraft. The hatches for the machine guns and the cutouts for the bomb bays were sealed. The Il-2I aircraft was armed with only two VY cannons with 150 rounds of ammunition. Two bombs weighing 250 kg each could be suspended on the outer bomb locks of the aircraft.

During tests, the Il-2I aircraft with a normal flight weight of 5383 kg reached a maximum horizontal speed of 415 km / h at an altitude of 1300 m, i.e., with practically the same flight weight, but with a more powerful engine, it could not exceed the speed of an experienced single-seat aircraft IL-2. Apparently, it was the lack of thoroughness of finishing the outer surface of the production Il-2 aircraft that affected it. Nevertheless, at an altitude of up to 4000 m, the speed of the Il-2I aircraft significantly exceeded the maximum speed of the enemy bombers Junkers Ju-87 and Heinkel He-111, which were widely used in the war. Air combat tests showed that at an altitude of up to 4000 m, the Il-2I freely attacks Ju-87 and Non-111 bombers, as well as enemy transport aircraft from all directions from behind when the latter flew along a broken route with turns, providing the ability to conduct an aimed defensive bombers fire.

The act on state tests of 09/28/1943 stated that:

"... 2) Flight data of the IL-2I in comparison with the two-seat IL-2 has been improved: the maximum speed at the ground is 6 km / h more (401 km / h instead of 395 km / h), at the border altitude at 10 km / h; ceiling at 1200 m (6500 m instead of 5300 m); takeoff run at 115 m (275 m instead of 390 m).

3) Improvement of flight data was due to weight reduction by 760 kg.

4) In terms of piloting technique, the Il-2I aircraft is similar to the aircraft produced in 1941-42.

5) Removal of PC, ShKAC and internal bomb racks for suspension of small aerial bombs and chemical ampoules reduced the aircraft's combat value as an attack aircraft and excluded the possibility of its use to destroy enemy manpower ...

6) Il-2I aircraft can be used to combat only certain types of enemy bombing and transport aircraft having relatively low speeds (He-111, Fw-200, Ju-87, Ju-52) at altitudes below 4000 m, however, Fw-200 aircraft can evade Il-2I attacks by gaining altitude due to better climb rate. The Il-2I can attack the faster Ju-88 and Do-215 bombers only by accident, since the latter, due to their higher speed, always have the opportunity to get away from the Il-2I.

7) The Il-2I aircraft cannot actively combat enemy fighters ... "

That is, the Il-2I as a fighter for bombers and transport aircraft clearly failed, and lost all the main qualities of a pure attack aircraft.

In this regard, in the statement of approval of the report on state tests of the Il-2I, the Commander-in-Chief of the Air Force of the Spacecraft A.A. Novikov imposed a resolution: "... to consider that the further construction of the Il-2I in the fighter version and the installation of the AM-42 engine (GKO decree No. 3336 of 05/17/43) on the IL-2 fighter version is inexpedient."

Heavy Fighter First flight: 1944 Ilyushin

The emergence of a new, more powerful AM-42 engine made it possible to return to the development of a heavy fighter to combat the latest high-speed bombers and enemy fighters. The Il-1 single-seat armored fighter of low and medium altitudes with an estimated maximum flight speed of about 600 km/h made it possible to conduct an active offensive air battle with the latest enemy fighters Bf-109 G-2 and FW-190A-4.

In accordance with the GKO decree, the Il-1 fighter was designed for the new AM-42 liquid-cooled engine with a takeoff power of 1471 kW (2000 hp), developed at the A.A. Mikulin Design Bureau and since May 1943, driven by an experienced heavy attack aircraft-bomber Il - AM-42. As in the IL-2I, the pilot, engine, engine cooling and lubrication systems, fuel tanks had to be protected in armor, reliably protecting them from being hit by bombers' defensive weapons.

S.V. Ilyushin did not share the concepts of an armored fighter, the design of the Il-1 was carried out from the standpoint of ensuring not only the specified flight performance of the fighter, but also the possibility of using this aircraft in the future as a high-speed and maneuverable attack aircraft.

When designing the Il-1 fighter, the main task was to ensure the highest aerodynamic perfection of the aircraft. It was achieved by using a new wing on the Il-1 with an increased specific load compared to the Il-2I and, accordingly, a smaller area than its own. The wing was composed of high-speed aerodynamic profiles with different relative width in span - the maximum in the center section, where the wheels of the main landing gear were removed, and the minimum on the detachable part of the wing. The main attention was paid to improving the shape of the armored hull, naturally, without unduly complicating the technology of its manufacture. This was achieved by a new arrangement of water and oil coolers for the engine cooling and lubrication systems, which were completely housed in the armored hull behind the front spar of the center section). The radiators were cooled with outside air coming through two air intakes at the junction of the center section nose with the fuselage on the right and left sides of the armored hull through channels that bend around the engine. After cooling the radiators, the air escaped through a slot on the lower surface of the armored hull, the value of which was adjusted depending on the operating mode of the engine with a special armored vehicle. Thanks to this layout solution, the contours of the armored hull were made smoother than on the Il-2, and the more aerodynamically advantageous scheme for blowing the radiators made it possible to reduce their size and resistance. The shapes of the cockpit canopy and other parts of the aircraft were also improved. For the IL-1, an original kinematic scheme was developed for cleaning the main aircraft supports backward along the flight to the center section with the wheels turning by 86 ° during the cleaning process, which made it possible to sharply reduce the midsection and drag of the landing gear fairings in comparison with the IL-2I. A simple and reliable kinematic scheme for turning the wheels with a single thrust, developed for the Il-1, was later used repeatedly on OKB aircraft, including such as the Il-28 and Il-76. The tail wheel was also made retractable. The blowing of the IL-1 models in the TsAGI wind tunnels confirmed the high aerodynamic perfection of the new aircraft: its drag at maximum speed was approximately 1.3 times lower than that of the IL-2I. The Il-1 fighter had a metal wing and tail and a wooden tail section of the fuselage. Its armament consisted of two 23 mm VYa cannons mounted in the wing consoles outside the zone swept by the propeller, on special steel mountings. Each gun had 150 rounds of ammunition.

To protect the tail of the aircraft from attacks of enemy fighters, a cassette was installed in the tail section of the fuselage, which housed 10 AG-2 aviation grenades. After dropping, these grenades first parachuted and then exploded, hitting the attacking enemy aircraft. The Il-1 fighter had no bomb armament, but if necessary, with an overload flight weight, it could carry 200 kg of bombs on an external sling.

May 19, 1944 test pilot V.K.Kokkinaki made the first flight on the Il-1 fighter. In the process of carrying out factory flight tests on the Il-1 aircraft with a normal flight weight of 5320 kg, the maximum horizontal flight speed of 580 km / h at an altitude of 3260 m was achieved.In terms of its speed characteristics in the range of heights from the ground and up to 4000 m, the Il-1 armored fighter significantly surpassed the FW-190A-4 fighter widely used in the Luftwaffe and was practically not inferior to the enemy's mass fighter, the light Bf-109G-2. According to V.K.Kokkinaki, the Il-1 fighter performed all aerobatics softly and easily. The plane completed a full turn in the horizontal plane at an altitude of 1000 m in 20 s, and the Bf-109G-2 fighter in 22 ... 23 s. With a combat turn in 13 ... 14 s, the Il-1 fighter gained an altitude of 900 m.However, thanks to the increased power of Soviet fighter aviation, which had won strategic air supremacy, by the middle of 1944 the need for a combat aircraft of this type had already disappeared, therefore, state tests IL-1 was not handed over.

Photo	Description
	Drawing Il-1
	Il-1 on tests

Bibliography

• Aircraft of the Ilyushin Design Bureau / Edited by G.V. Novozhilova /
• History of aircraft designs in the USSR, 1938-1950. /V.B. Shavrov /

January 02, 2020
Il-10, with an onboard gunner, which had the same wing as the Il-1, had 365 kg more empty weight. (The odd numbers of the aircraft were occupied by fighters and subsequently the Il-1 aircraft was assigned the index 10). At the same time, the ground speed of the attack aircraft was 18 km / h less, at an altitude of 29 km / h.
However, this is purely during testing, where, as you know, the designers go to make the plane as light as possible. The presence of the shooter himself, his weapon, ammunition and armor protection significantly reduces the flight data of the aircraft, while the probability of hitting the shooter himself is much greater than the predicted possibility of hitting his target. (The probability of a shooter being hit by German fighter jets in one attack was about 2 to 2.5 times higher than the ability to shoot down an attack aircraft he was protecting under the same conditions, and 3 to 4.5 times higher than the probability of a German fighter being destroyed by return air fire. arrow.)
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January 02, 2020
Percentage of meetings of Il-2 attack aircraft with Luftwaffe fighters during combat missions in the period 1944 - 1945. on average, it was no more than 10-15% of the total number of sorties of groups. The probability of a shooter being hit by German fighters in one attack was about 2 - 2.5 times higher than the ability to shoot down an attack aircraft he was protecting under the same conditions, and 3 - 4.5 times higher than the probability of a German fighter being destroyed by return fire from an aerial gunner ... And although by the end of the war the expediency of having a gunner raised great doubts (attack aircraft were reliably covered by fighters from enemy attacks and the very likelihood of encounters with enemy fighters was minimal), the second crew member was retained both on the Il-10 and on the already modern prototype Il-102 ( where it is true that the arrow-operator has already solved broader problems).
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