Aviation of Word War II
A further development of the Yak 1M airframe and powered by the M-105 PF engine VISh-105 SV propeller combination, the Yak 3 was the smallest and lightest combat fighter to see large scale production and use during World War II. The Yak 3 was also the first Russian fighter with a superior performance to contemporary Luttwatle fighters in use on the Eastern Front. At this stage of the war. the Soviet Union was out producing Lultwaffe aircraft in both quantity and quality. The excellent power loading of 4.83 Ib/hp allowed exceptional performance for the Yak 3s relatively low power. A Yak 3 could complete a full 360° turn within 18.5 seconds, something the Lultwaffe pilots could only dream of!
Further attempts to improve the Yak fighter began during the summer of 1942 when K.V. Sinelshchikov was assigned the task of redesigning the Yak to improve endurance, fire power, and combat capabilities. With all modifications directed toward decreasing weight and improving performance a standard Yak 1M fuselage was used as the Yak 3 prototype, which had been fitted with a newly designed wing with a reduced span from 32 feet 9.75 inches to 30 feet 2.5 inches. Original intentions had been to mate the new M-107 powerplant with an anticipated 1500 to 1600 hp, in the event the new engine did not materialize and the M-105PF was retained. A number of aerodynamic refinements were introduced, such as a recounted red oil cooler intake and a one piece frameless windscreen which provided the pilot with excellent all-round visibility. The production version received an enlarged oil cooler under the fuselage resulting in removing the front oil cooler from beneath the nose. The first production batches were equipped with the Yak 1M standard armament of an engine mounted 20mm cannon, and a single 1 2.7mm Berezin UB machine gun in the port upper engine decking, but main production aircraft received an additional similar machine gun in the starboard decking.
Prototype flight trials began during early 1943 in Moscow with high-speed flight trials far exceeding expectations. 410 mph at 9.840 ft and 422 mph at 12.140 ft with low level characteristics being particularly pleasing. The loss of the prototype due to a structural failure during aerobatics delayed full State Acceptance until October of 1943. but demands from front line pilots for a more efficient fighter forced the Red Air Force to introduce the fighter into Service before completion of State Acceptance.
The Yak 3 saw action for the first time in June of 1943 at the end of the German OPERATION ZITADELLE in the Kursk area, and pilot's comments were enthusiastic about the combat value of the new weapon. The Yak 3 provided a real challenge to the Messerschmitt Bf 109F and G and the Focke Wulf Fw 190A Ideally suited for low altitude combat operations, light stick pressure produced fast and accurate snap rolls and all maneuvers could be performed precisely and smoothly. But it demanded careful handling at low speeds, stalling speed was high and the Yak-3 tended to drop a wing during the landing approach unless speed was kept up. It tended to swing on take off and landing, and ground loops were not uncommon among green pilots.
Large scale production of the Yak 3 was begun at GAZ 115 and GAZ 286 during the spring of 1944, only reaching front line fighter regiments in quantity during the summer of 1944. Technical and structural problems had delayed development for some time. The undercarriage in particular was considered unreliable on hard field conditions.
A total of 4560 Yak-3 was built during 1944 - 1945.
* Forcing of the engine during 10 minutes.
** On speed making 90 % from maximal.
The Yak-3P (cannon) with three B-20 cannons of 20 mm caliber was a modification of the serial Yak-3 aircraft with a VK-105PF2 engine and differed from it mainly in armament.
Instead of a ShVAK motor cannon with a supply of 120 rounds and two synchronous UBS machine guns with a supply of 150 rounds each, the Yak-3P was equipped with one B-20M motor cannon (120 rounds) and two synchronous B-20S (130 rounds each) . In this regard, the layout of weapons installations has changed. The mass of weapons and ammunition became 11 kg less than that of the serial Yak-3P, the mass of weapon mounts remained practically unchanged. Fire control for all three points on the aircraft was pneumoelectric and was carried out by two combined systems. Pneumatic reloading has been introduced for the motor gun instead of a mechanical one. Experimental cannons B-20 in synchronous and motor versions passed state tests at the Research Institute of the Air Force and were adopted by the GKO decree of October 10, 1944.
The mass of a second salvo for the Yak-3P is 3.52 kg/s; for comparison: Me-109G-6 had 2.74 kg / s, Me-110 - 2.85 kg / s, FW-190A-8 - 3.44 kg / s, Spitfire IX - 3.10 kg / s, "Aerocobra" P-39Q-10 - 3.18 kg / s. When firing from B-20 cannons in the entire range of speeds and with all evolutions, the Yak-3P behaved stably. The impact on the aiming of the fire had little effect.
The middle parts of the ribs were also reinforced on the aircraft; locks were installed on additional chassis shields; improved gasoline meters with a scale increased to 160° were installed; the Venturi tube was moved from the water radiator tunnel to the wing fairing; radio receiver RSI-4A was replaced by RSI-6M.
The modification was made by OKB A.S. Yakovlev by the decree of the State Defense Committee of December 29, 1944. This decree provided for the development of two copies of the Yak-3P by January 15, 1945 and the organization of their serial production from February 1945. March 23 to April 9, 1945 (pilot V. G. Ivanov, chief aircraft engineer I. A. Kolosov, armament - A. G. Aronov). 37 flights were made with a total duration of 17 hours 39 minutes.
According to the results of state tests, it was noted that an aircraft with three B-20 guns is needed for the Air Force.
At the same time, an attempt to install B-20 guns on La-7 ended in failure due to the low reliability of these guns. Of the three aircraft (serial numbers 45214414, 45214415, 45214416) that took part in the tests, none of them managed to achieve the required indicator of 5000 shells fired from one aircraft without failures. For all three aircraft, failure occurred after a little more than 3,000 rounds had been fired. Reliability indicators were achieved only with the installation of NS-23 guns on the aircraft.
The Yak-3P was serially built at factories N 292 in Saratov and N 31 in Tbilisi from April 1945 to mid-1946. From August 1, 1945, all Yak-3P VK-105PF2 were produced with only three guns B-20. A total of 596 Yak-3Ps were built.
Comparative Analysis of Designs and FTD of Soviet and German Fighters that Took Part in the WWII
Flight Technical Data - FTD
The final milestone in the development of the Yak-1 design was the Yak-1M, which appeared in mid-1943 and was renamed Yak-3 when it was launched into series. The main differences from the previous modifications: metal spars and wing ribs were used instead of wooden ones, which gave tangible weight savings. The wing itself is reduced in span and area, and the stabilizer and keel are also slightly reduced. Instead of one oil cooler located under the engine, two smaller sizes are installed, transferred to the root of the wing. The linen covering of the aft fuselage was replaced with plywood. The outlines of the cockpit canopy have become smoother and smoother. The takeoff weight of the vehicle dropped to 2690 kg.
The M-105PF-2 engine (hereinafter - VK-105PF-2, since since 1944 the engines in the USSR were given new designations according to the initials of their developers: VK - Vladimir Klimov), boosted to 1250 hp. at an altitude of 2000 meters. The armament consisted of a ShVAK motor-gun and one (in the first 197 copies), and then two synchronous UBS heavy machine guns.
The aircraft was produced in large series since March 1944. A total of 4,200 aircraft were built, but some of them were already built after the end of the war.
Due to a decrease in take-off weight, improved aerodynamics and an increase in engine power, the Yak-3 had the highest flight performance of all Yakovlev fighters that took an active part in the Great Patriotic War. Its specific power load was 2.12 kg/l with (like the Bf 109F-4), the maximum speed reached 644 km/h at an altitude of 4000 m, the rate of climb at the ground was 22 m/s, and the minimum turn time was 21 s. These numbers can certainly be considered outstanding. According to its flight data, the Yak-3 was superior to the later modifications of the Messerschmitt, with the exception of speed at high altitudes.