Yakovlev Yak-3

Yakovlev Yak-3 is considered one of the best World War 2 fighters, invariably praised by those who flew it in combat for its remarkable performance.

The Germans also treated it with respect, which is perhaps best illustrated by Generalleutnant Walter Schwabedissen’s remark: The Yak-3 was a tough nut to crack for our pilots. It outperformed our machines in speed, maneuverability and rate of climb.
The emergence of Yak-3 was a compromise between the need to improve the Yak-1’s characteristics and the limitations of Soviet aircraft industry and its outdated technologies. The basic design concept took those shortcomings into account, which allowed a rapid launch of mass production of this inexpensive fighter. This in turn would provide frontline units with timely deliveries of new equipment to recoup combat losses.
The key to Yak-3’s success was not the use of a new powerplant (in those days hard to come by in the USSR), but rather squeezing every bit of performance out of the M-105PF engine, which resulted in a five percent increase in power output. In combination with some serious weight shedding, the Yak-3 had a significantly better performance than the Yak-1. At altitudes up to 5,000 m (which is where most of the air combat over Eastern Front took place), Yak-3 outperformed both the Bf-109 and Fw-190 in rate of climb and maneuverability. Unlike the Yak-1, the new fighter could also stay with the enemy in a dive.

Yak3   zdj1

Its advantages notwithstanding, the Yak-3 also had some serious drawbacks, which affected its modernization potential and limited the scope of combat application of the machine. Its main weakness was a rather modest fuel capacity, which limited the fighter’s range making it unsuitable for long-range combat patrols (with twenty percent fuel reserves, the Yak-3’s endurance was just about 45 minutes). Also, because of its “short legs”, the fighter had to be based fairly close to the frontline. Although the Yak-3’s armament did provide enough punch to combat enemy fighters, it was insufficient against bombers. There were more problems to overcome if the machine were ever to be equipped with a more powerful engine, once such became available. It quickly became obvious that such a modification would never be possible due to short landing gear struts and lack of space for installation of more efficient water and oil radiators that a new powerplant would require.

Yak3   zdj2

Origins of the design
The history of the Yak-3 design (not to be confused with the experimental I-30 aircraft built in 1941 and armed with three cannons – the first design to have received the designation) dates back to the fall of 1942 and the emergence of the Yak-1M Moskit (Mosquito) – a light-weight version of the Yak-1, powered by the M-106P engine (the M-105PF and M-107A engines were also considered as powerplants for the new design).
In its early iteration the Moskit project was based on the Yak-1 airframe and retained its characteristic hump behind the cockpit, but fairly soon the design underwent radical changes. The new fighter was originally designed around a stock Yak-1b fuselage, which was modified to accommodate a BS gun and a new coolant radiator ducting. Mated to the fuselage was the Yak-9 wooden wing with its duralumin main spar and four load-bearing ribs, which featured reduced wingspan and wing area (9.2 m and 14.7 m2, respectively). Since the new design was much lighter, the resultant wing loading was the same as in the Yak-9 carrying identical armament. Elimination of aileron counterbalance provided additional 10 kg in weight saving. In addition, the Yak-1M wing was split along the aircraft’s longitudinal axis, which facilitated removal of damaged panels and made their ground transport a lot easier.
The overall design of the landing gear was the same as on the Yak-1, but its shock absorbers featured a greater stroke, so some of the components were adopted from Yak-7. Retractable tailwheel and tailplane were unmodified Yak-1 units. There were some minor modifications to flight control mechanisms, which included lowering the rudder pedals by 50 mm and relocating the elevator control cables. Armament was limited to a single MP-20 cannon firing through the propeller hub (120 rounds of ammunition) and a fully synchronized BS machine gun (200 rounds) mounted on the portside above the engine. The BS gun was equipped with a simple iron ring sight. According to design calculations, the aircraft’s all up weight should not have exceeded 2,650 kg and its supercharged M-105PF engine was expected to propel the fighter to 630 – 640 km/h.

 Yak3   zdj3