|A LaGG-3 before take off|
|National origin||Soviet Union|
|Designer||V. P. Gorbunov|
|Built by||21 (Gorky), 31 (Taganrog/Tbilisi), 23/153 (Leningrad/Novosibirsk)|
|First flight||28 March 1940|
|Primary user||Soviet Union|
|Developed into||Lavochkin La-5|
The Lavochkin-Gorbunov-Gudkov LaGG-3 (Лавочкин-Горбунов-Гудков ЛаГГ-3) was a Soviet fighter aircraft of World War II. It was a refinement of the earlier LaGG-1 and was one of the most modern aircraft available to the Soviet Air Force at the time of Germany's invasion in 1941. Despite its wooden construction, it was both overweight and underpowered. At one point in the war, on average 12 LaGG-3s were being completed daily and 6,528 had been built in total when Factory 31 in Tbilisi switched production to the Yak-3 in 1944.
The prototype of the LaGG-3 was called the I-301 and was designed by Semyon A. Lavochkin, Vladimir P. Gorbunov and Mikhail I. Gudkov. The prototype was later renamed the LaGG-1 and production aircraft were called the LaGG-3. The prototype was designed and produced by the GAZ-301 factory in Khimki to the North West of Moscow. The design was approved for production in January of 1940 and in the prototype's name the I- prefix stood for istrebitel "destroyer" and the number signified the design bureau responsible (which in this case was the GAZ-301 factory). The I-301 was a single-seat, low-wing monoplane, with a semi-monocoque fuselage, and skinned with birch veneer and plywood.
The I-301 airframe was partially made of "delta wood": a material composed of very thin (0.35–0.55 mm) layers of birch or pine wood veneer, and a phenol-formaldehyde resin known as VIAM-B-3, which together were baked at high temperatures and pressures. Delta wood was used for critical parts of the airframe. This novel construction material had tensile strength comparable to that of non-hardened aluminum alloys and only 30% lower than that of precipitation hardened D-1A grade duralumin. It was also incombustible and completely invulnerable to rot, with service life measured in decades in adverse conditions. During production of the prototype, it was discovered that the adhesive used in delta wood caused skin irritation and safety procedures needed to be devised for workers.
The full wooden wing (with plywood surfaces) was analogous to that of the Yak-1. The only difference was that the LaGG's wings were built from two spars. The fuselage was of similar construction to the MiG-1.
The I-301 was armed with one axial mounted MP-6 23 mm autocannon designed by Ya. Taubin which fired through a hollow propeller shaft in the "vee" between the engine cylinders and two synchronized 12.7 mm (0.50 in) Berezin UBS machine guns in the cowl. The MP-6 had 81 rounds of ammunition while the Berezin UBS had 230 rounds per gun. The MP-6 was abandoned after the prototype due to excessive recoil forces that damaged engine fittings. The I-301 used a Klimov M-105P engine of 780 kW (1,050 hp) a licensed derivative of the Hispano-Suiza HS 12Y with a two-speed two-stage supercharger. At 2,968 kg (6,543 lb) it was heavier than its competitors the Yak-1 and MiG-1, which meant its ceiling of 9,800 m (32,000 ft) was less than both. The I-301 took to the air for the first time on 30 March 1940 and by 12 June 1940 the manufacturer's tests were completed. The test pilot, A. Nikashin, reported that the fit and finish of the prototype was very good, it handled well, was maneuverable, and could be mastered by pilots of average ability.
On 14 June 1940 state acceptance trials began and it reached 510 km/h (320 mph) at sea level, 584 km/h (363 mph) at 4,700 m (15,400 ft), and climbed to 5,000 m (16,400 ft) in 5.85 minutes. Later, the I-301 reached 604 km/h (375 mph) at 4,950 m (16,250 ft) with its radiator doors shut making it the fastest M-105P powered aircraft. The I-301 had a fuel capacity of 340 L (90 US gal) carried in three self-sealing fuel tanks between the wing spars in the wing's center-section giving it a range of 600 km (373 mi). During testing the state specification was increased to a maximum range of 1,000 km (620 mi) and fuel capacity was increased to 450 L (119 US gal). Aircraft with this fuel capacity were designated as LaGG-3's while the prototype was re-designated as the LaGG-1. The test flights revealed 114 faults that needed to be fixed but the project was given high priority so most of these faults were to be addressed in production aircraft.
On 29 June 1940 the LaGG-3 was accepted for production and the first plant to build LaGG-3's was Plant No.23 in Leningrad and was tested in December 1940. As soon they were built, the first aircraft were sent to their units in Soviet Asia. The LaGG-3 proved immensely unpopular with pilots. It was somewhat hard to control as it reacted sluggishly to stick forces. In particular, it was difficult to pull out of a dive, and if the stick was pulled too hard it tended to fall into a spin. As a consequence, sharp turns were difficult to perform. Moreover, pilots reported several imperfections: badly made hydraulic systems, broken connecting rods, oil leaks, engine overheating, rapid engine wear and loss of power. Other faults included defective landing gear, tail wheel failure, poor quality cockpit glass, poorly finished cowling panels, and poor quality delta wood panels due to rushed production as a result of the German invasion. The quality of aircraft varied widely from factory to factory.
As reports of these problems came back to Lavochkin's Experimental Design Bureau (OKB) in February 1941 no less than 2,228 modifications were ordered to be introduced into the series. Actually, despite the military's doubts, the Soviet government ordered 66 series of the Lavochkin fighter, which underwent a host of successive improvements in engines, propeller, and armament. The airframe was lightened as well. The LaGG team re-examined the design and pared down the structure as much as possible. Moreover, automatic slats were added to the wings to improve climb and maneuverability on the 35th Series and further weight was saved by installing lighter armament (the first four series were equipped with one axial Berezin machine gun firing through a hollow propeller shaft, two more synchronized cowl mounted Berezin machine guns with 200 rounds per gun and two synchronized 7.62 mm (0.3 in) ShKAS machine guns above and to the rear of the cowling with 325 rounds per gun; from 8th Series the axial Berezin was replaced by a 20 mm (0.79 in) ShVAK, coupled with a port Berezin in the cowling. But the improvement was slight and, thus, without an alternative powerplant, when the LaGG-3 was first committed to combat in July 1941, it was effective against bombers but it was completely outclassed by the Messerschmitt Bf 109 F.
In combat, the main advantage of the LaGG-3 was the strength of its airframe and the fact that it did not easily catch fire, despite the extensive use of wood. However, the laminated wooden panels did tend to shatter when hit by high explosive rounds and Soviet pilots nicknamed the plane Lakirovanny Garantirovanny Grob, or "guaranteed varnished coffin".
On the whole, pilots disliked the type. Pilot Viktor M. Sinaisky recalled:
It was an unpleasant customer! Preparing the LaGG-3 for flight demanded more time in comparison with other planes. All cylinders were ... to be synchronized: God forbid you should change the gas distribution! We were strictly forbidden to touch the engine ... [T]here were constant problems with [the] water-cooled engines in winter... [T]here was no anti-freeze liquid [and y]ou couldn't keep the engine running all night long, so you had to pour hot water into the cooling system ... in the morning. ... [P]ilots didn't like flying the LaGG-3 – a heavy beast with a weak ... engine... [T]hey got used to it ... [but] we had higher losses on LaGG-3 than on I-16s.
Later in 1941, the LaGG-3 appeared with an internally balanced rudder, retractable ski landing gear for the winter, retractable tailwheel and plumbed for drop tanks. The result was still not good enough. Even with the lighter airframe and revised supercharged engine, the LaGG-3 was underpowered. However, despite its limitations, some Soviet pilots managed to reach the status of ace flying the LaGG-3. G. I. Grigor'yev, from 178th IAP, was credited of at least 11 air victories plus two shared. But pictures of his LaGG-3 "Yellow 6", in November–December 1941, show 15 "stars", so his score was probably higher. Experiments with fitting a Shvetsov M-82 radial engine to the LaGG-3 airframe finally solved the power problem and led to the Lavochkin La-5 and La-7.
|I-200/MiG-3||630 km/h (390 mph)||615 km/h (382 mph)|
|I-26/Yak-1||586 km/h (364 mph)||560 km/h (348 mph)|
|I-301/LaGG-3||604 km/h (375 mph)||549 km/h (341 mph)|
Data from Jane's Fighting Aircraft of World War II
Aircraft of comparable role, configuration, and era
Media related to Lavochkin LaGG-3 at Wikimedia Commons