La-5 fighter appeared due to the modification of LaGG-3 to the new air-cooled engine M-82 A.D. Shvetsov, who at that time was not in demand. Due to its significantly greater power in comparison with the M-105P, the LaGG-5 fighter acquired those qualities that he so lacked: the speed and rate of climb increased significantly, and vertical maneuverability improved. The new aircraft was created in the spring of 1942, the GKO Decree was issued on August 6, and after 2 days the NKAP order No. 683, according to which the new fighter became known as La-5 – “Lavochkin-5” and after testing it, under the La-5 brand, immediately launched into the series.
Along with improving reliability, the most important area for improving La-5 was weight loss. Replacing the electric start of the motor with an air one saved 20 kg, improved gluing quality – another 20 kg, removing cargo in the tail — 15 kg, then “cleaned” the pipelines and control wiring. As a result, the take-off weight was reduced from 3370 kg in the experimental vehicle to 3200 kg in a series.
Progressive technological processes were introduced, which allowed increasing the pace of La-5 production. For example, at first, the La-5 bonnets had to be manually knocked out, but on July 1, 1942, the first dies were handed over, ensuring the daily production of parts for 2 aircraft, and by the end of the month they organized a new section with a daily output of 6 sets. The same thing happened with casting and hot stamping. Throughout the glider, work was underway to replace the delta wood with regular wood. Ultimately, only power frames, plumage spars, and plating in specially loaded zones were made of the “delta”. Without loss of strength, it was possible to reduce the weight of the aircraft and its cost.
Engine. The plant guaranteed the operating time of the M-82A before repair 100 hours, but in reality, the resource was less. Due to the deterioration of the fit of the piston pairs and rings, oil accumulated in the combustion chambers of the lower cylinders, the engine smoked and filled the entire fuselage. But if not all the accumulated oil was ejected through the exhaust pipes, a hard blow occurred on the compression stroke and, as a result, a break in the connecting rod or destruction of the cylinder head. The VG-12 candles used on the M-82 stood for 5 hours each, and during intense battles, one La-5 required 14 candles per day. The problem lay in the unsuccessful shape of the cylinder heads: the candles were constantly in the oil, from which they were soaked, and lead from leaded gasoline settled on the soot.
Initially, the La-5 M-82A Flight Operations Manual permitted the take-off mode (1700 hp) off the ground for 5 minutes. Experienced aircraft in this mode accelerated to 600 km / h, and at face value (1400 hp) only to 515 km / h. But if the pilot was fond of and did not turn off the afterburner on time, the new motor jammed after 10 minutes, and the worked one did not stretch the allowed 5 minutes. The combatant pilots constantly reported that some of the La-5s of their group had not returned from departure due to a motor failure in battle. Tests conducted at LII confirmed the objectivity of the claims, and it was forbidden to use afterburner in battle. Without it, the speed at the ground dropped to 505-510 km / h, from 600 to 580 km / h the speed at the 2nd border of altitude decreased, and the climb time of 5000 m increased from 5.2 minutes in an experienced aircraft to 6.0.
The first La-5s, like LaGG-3, had no slats and were distinguished by a tendency to stall on the wing. GKO Decree No. 1895ss of June 7, 1942, obliged to introduce mechanization of the leading edge of the wing on LaGG-3 and La-5 from July 1, but by the end of the first ten days of July, only 7 LaGG-3 and 8 La-5 were able to do this. Only by August, all planes began to produce with slats.
In the summer of 1942, work was done on La-5 to improve the fit of hatches and chassis flaps. They ensured the synchronization of the release of the right and left slats, they were better fitted and lightened. We envisioned the release of flap flaps on a bend, reducing its radius and runtime. According to the results of the research TsAGI changed the design and installation of the Pitot tube. Modified the electrical system.
On July 24, the order of the NKAP and the Air Force No. 559a / s / 032 on the use of armor on fighters was issued. First, an armored back was installed on La-5, and tank protection was also introduced. Then, by GKO decree No. 2359ss of October 1, 1942, frontal bulletproof glass was introduced. Also, the same document determined the use of the red illumination of the reticle on the La and Yak fighters, the button electro-pneumatic release of guns of the Me-109 type instead of a tight mechanical trigger.
By order of the NKAP No. 605s dated August 8, from August 10, on each La-5, it was required to install an RSI-4 radio receiver, and on every third – a transmitter, as well as an RPK-10 radio meteorological station. Although it was not possible to meet the deadlines (for 2 days!), The matter nevertheless moved forward, and Soviet fighters began to receive radio navigation and communications.
By the end of 1942, La-5 began to be launched in Gorky with a substantially modified nose: the double skin finally disappeared, the fuselage became lighter, and the labor intensity decreased. By that time, on the rear frame of the movable part of the lantern, on the recommendation of TsAGI, they placed a stacker, smoothing the step between the cabin and the garrott. The kinematics of the tail support were also changed, now its wheel was pulled higher, and the wings did not protrude beyond the contour of the tail.
In December 1942, La-5 began production at Plant No. 31 in Tbilisi, where LaGG-3 production continued. By the end of the year, this plant built 22 new fighters and handed over 5 more at the beginning of the next.
The first aviation regiments that had this fighter in service appeared on the front in the fall of 1942 near Stalingrad.
La-5 quickly gained recognition. The pilots liked not only its high characteristics and powerful weapons (two ShVAK cannons), but also the air-cooled motor, which had greater survivability than the liquid-cooled motor, and at the same time as protection from enemy fire from the front hemisphere.
The first production version of the La-5 with the M-82A engine was discontinued in the summer of 1943.
- Crew 1 pers.
- Wing span, m 9.76
- Wing Area, m² 17.50
- Aircraft Length, m 8.67
- Engine: M-82A 1700 hp
- Masses and loads, kg:
- Empty 2800
- Norm take-off 3230
- Maximum speed at the ground, km / h 509
- Max. speed at an altitude of 6250m, km / h 580
- Max. rate of climb, m / min 833
- Practical ceiling, m 9500
- Practical range, km 1190