Fighter La-5FN: flight performance

2024 Author: Henry Conors | [email protected]. Last modified: 2024-02-12 02:55

During the Great Patriotic War, fighter planes made a significant contribution to the cause of victory. Despite the fact that the German air force was equipped with such powerful combat vehicles as the Messerschmitt Bf 109G and the Focke-Wulf FW 190A, Soviet aviation dominated the skies. Wehrmacht air vehicles were significantly inferior to the product of the designers of the USSR, which was the La-5FN fighter.

What was the German aviation inferior to?

The Soviet fighter La-5FN, when maneuvering vertically and horizontally, was much better than the main German fighter "Messerschmitt" Bf 109G, because after several turns it could go into the enemy's tail and produce aimed fire. This was possible even with almost the same speed performance as these two rival models.

The La-5FN fighter left absolutely no chance of victory for the German Focke-Wulf FW 190A. This model was inferior even in speed. Appeared inIn the armed forces of the Wehrmacht, the FW190A-8 fighter in terms of maneuverability had no advantages over the La-5FN, which had high speed characteristics and good maneuverability, which, together with the experience of the pilot, ensured the victory of the Soviet aircraft in an air battle. According to the instructions issued by the German command to the flight personnel, the Soviet La-5FN fighter was considered the most dangerous enemy, in the battle with which the Wehrmacht pilots were required to be exceptionally attentive and collected.

Beginning of creation

In 1941, designer S. A. Lavochkin carried out the modernization of the LaGT-3 aircraft - a fighter, which at that time had already ceased to meet all the requirements. There was an urgent need for a new model capable of withstanding modern air combat. LaGG-3 was taken as a basis.

It was decided to use the ASh-82FN propeller group with a power of 1700 hp in the new machine. and synchronized twenty-millimeter guns ShVAK. At one time, designers such as A. I. tried to equip their aircraft with this engine. Mikoyan, S. V. Ilyushin, V. M. Petlyakov and A. S. Yakovlev. But best of all, he took root in the S. A. aircraft. Lavochkin.

Initially, the ASh-82FN engine did not fit into the fuselage of the aircraft, since it was developed for the M-105 model. But the designers managed to equip their product with a two-row radial engine, so that the design, geometry and dimensions of the LaGG-3 airframe adopted as the basis remained unchanged.

Thanks to the ASh-82FN engine, the La-5FN fighter received improved maneuverability and speed, which was especially reflected in the quality of deep turn and vertical maneuvering. The presence of 20 mm ShVAK cannons in the Soviet La-5 made it possible for pilots to take an offensive rather than a defensive position in air battles with German vehicles.

Application in new engine design

The forced Shvetsov ASh-82F engine began to be used in such fighters as the La-5F (which was reflected in the abbreviation of the aircraft) and La-5FN. The abbreviation of the latter indicates that it belongs to the forced models with direct fuel injection.

According to legend, equipping this Soviet fighter with a powerful engine was caused by Stalin's dissatisfaction with the technical capabilities of the ASh-82 in afterburner mode. They were enough for a few minutes. At the direction of Stalin, one such engine was launched in this mode and worked until it failed. The recorded time showed a large motor resource - it exceeded 50 hours.

For combat fighters, these are good indicators. In the design of the La-5FN aircraft, this engine gave power of 1750-1850 hp. and maintained the afterburner mode for at least ten minutes. With a large supply of fuel, the period of such a regime could be extended.

Testing

The La-5FN fighter is one of the modifications of the La-5 aircraft. In the spring of 1942, in Lyubertsy, they underwent a comprehensive test, after which their design was approved. Testingrepresented an impromptu dogfight between the La-5FN and the captured Bf 109G-2. After the battle, conclusions were drawn: the Soviet fighter is ideal for operating at low and medium altitudes, which were the main ones for the aviation of the Eastern Front.

In April of this year, the State Defense Committee gave permission to start mass production, which resulted in the release of several modifications of the La-5, among which was the La-5FN fighter. The photo below shows the design features of this aircraft.

What flights was it intended for?

Air combat at low altitude is considered the main task for which the La-5FN fighter was designed, the design and controllability of which made it the best model in Soviet aviation of those times. The effectiveness of the ailerons and rate of climb of the La-5FN surpassed the performance of the German FW 190A-8, which was much heavier and had low acceleration characteristics. But the enemy fighter had the ability, during dive maneuvers at high speeds, to make a combat turn to attack the La-5FN fighter.

The controllability of the Soviet machine provided that by diving at high speeds it evaded attacks and itself moved into position for an attack in a gentle climb. This was possible, since the La-5FN had a better rate of climb compared to the FW 190A-8, which made it possible to overtake a German fighter on a steep slope. Among the recommendations that were given to pilots by instructors in flight schools in the event of a collision in the sky with the FW 190A-8, there was a ban on prolonged maneuvering and slowing down. In addition, pilots should remember that the aircraft is not designed to perform a long afterburner, since the engine power is designed for less than forty minutes.

Permissible speed

The aircraft could develop speed at cruising power and afterburner. They had different allowable parameters and differed for ground and sea levels.

The La-5FN fighter above sea level in afterburner could reach speeds of up to 520 km/h.
At cruising power at this level, the speed was 409 km/h.
Afterburner was allowed above ground level at a kilometer distance. The speed was 540 km / h. It was also acceptable for cruising power, but already at an altitude of 2400 meters.
For a distance of 5 thousand meters, cruising power increased to 560 km/h.

The design of the engine, which was equipped with the La-5FN fighter, was not adapted for afterburner at a distance exceeding two kilometers. This is due to the peculiarities of the air channel of the throttle, the flow area of which did not provide maximum motor power.

Fighter La-5 FN. Features

The aircraft was highly appreciated by both Soviet and German and British aviation specialists. The La-5FN fighter aircraft was considered the best among all analogues of the Eastern Front.

the cockpit was designed for only one pilot;
fighter weightwas 3290 kg;
dimensions (length and size of the wing) - 8.67 x 9.8 meters;
wing area - 17.5 sq. m;
load per wing per square meter was 191kg;
the design was equipped with one M-82FN engine with a power of 1750 hp;
at an altitude of 6250 meters, the car developed a flight speed of up to 634 km/h;
practical ceiling (maximum altitude) for a fighter - 10750 meters;
average rate of climb - 16.6 m/s;
tanks are designed for 460 liters;
oil weight - 46 kg;
two 20mm ShVAK guns were equipped with La-5FN;
fighter capable of withstanding a bomb load of up to 100 kg;
the aircraft was intended for distances not exceeding 930 km.

Fighter La-5FN. Device

The design of this aircraft is characterized by direct injection of fuel into the cylinders.
Instead of exhaust manifolds in the aircraft, individual pipes were used, of which there were seven pieces on each side.

The top of the hood contained a special air intake.
The fuselage fairing was lowered, the shape of the canopy was also changed (they were designed according to Yakovlev A. S. Yak-9).
The use of the instrument panel made it possible to fly at night and in bad weather conditions.
A number of improvements have been made,which touched on the internal sealing and thermal insulation of the La-5FN cabin. The fighter received an improvement in overall aerodynamics.
To improve visibility, the aircraft was equipped with a new canopy, which, especially for an emergency, was supplemented with an easily removable sliding part.
The design was equipped with a tail wheel. It could retract during flight, and orient itself when taxiing.
Two-spar wings had plywood skin and contained automatic duralumin slats, which with the help of landing flaps, if necessary, could deviate by 60 degrees.
Birch veneer was used in the production of the fuselage and keel. It was from several layers, which were pasted over with a canvas.
A welded motor mount made of steel pipes was intended for mounting the ASh-82FN double-row radial engine. The engine itself was located in a tank, which was constructed from easily removable duralumin panels. This provided free access to the motor during its repair or maintenance.

What was the plane sheathed with?

Most variants of combat aircraft of the La-5 model had an all-wood construction, which was constantly improved. Despite the fact that the tree had fire resistance, the strength of this material was not enough. In the La-5FN model, the developers paid special attention to protecting the pilot and engine. The tree was replaced with duralumin and iron, which ensured uninterrupted and reliable operation of the motor even with shrapnel hits. Fuelthe tanks were not armored, and this made them very vulnerable in the event of an attack. The wooden wing spar was replaced with a metal one. For the safety of the pilot and fuel tanks, armored glass began to be used in the production of the fighter, the thickness of which for the frontal part of the cockpit was 57 mm. An armored headboard (68 mm) was made from this material. The armored back was made of 0.7 cm thick steel.

Arrangement of the cockpit

The upper hemisphere of the cabin provided good visibility and all-round visibility. Forward visibility was limited. This is due to the low landing of the pilot. The operation of the engine left a large plume of exhaust gases behind the aircraft. The pilot used a high- altitude oxygen system, which was a diaphragm direct-flow economizer (the idea was taken from the German economizer system).

If earlier the propeller pitch, radiators, blinds, trimmers and other things were controlled by various hand rods - levers, which was a disadvantage, since during the battle the pilot was distracted when moving the rods to speed up, then in La-5FN everything was automated. The pilot could easily control all units of the propeller group, fire and control the operation of the guns, without looking up from the battle. Only the power plant was controlled by levers, everything else was done by automation.

How does takeoff happen?

During the launch of a fighter jet, its engine exhibits acceptable power fluctuations. A short distance is provided for the takeoff run of the aircraft. When taking off, the tail of a fighterrises slowly. Piloting is difficult at the moment because the clearance from the propeller to the ground is small.

Causes of stalls

Any aircraft has its own characteristics and disadvantages when flying. One of the last is stalling. The La-5FN fighter is not without this drawback. Stall characteristics have been analyzed and taken into account by specialists in the creation of the next, more advanced generations of aircraft. Reasons for stalling:

Reduce speed. When retracting the landing gear and flaps, the slats are released at a speed of 200-210 km/h. As the speed decreases, the effectiveness of the ailerons decreases. Fighter skidding or braking at 180 km/h causes it to roll over the wing, as it is difficult for the pilot to dampen the roll at this speed. Stalling can also occur with landing gear and flaps extended if the pilot continues to pull the lever towards himself as the fighter enters the maximum angles achievable for him.
Performing sharp turns. With the rapid deployment of the La-5FN, the air flow on the wing is stalled. As the speed increases, the reduction in aileron effectiveness is more pronounced. When the fighter accelerates to 320 km / h and reaches a height of 2400 meters, at which a full turn is performed for 30 seconds, the design of the machine receives an overload of 2, 6G. If there is a need to perform sharp movements with the ailerons, then it is natural for the handle in the cockpit to move in the direction of rotation.

To prevent the plane from crashing, there are appropriateinstructions on how long it takes to complete a turn at a certain altitude. So, for 2400 meters, 28 seconds are provided, and at a kilometer altitude, the turn should be completed in 25 seconds.

Flight stability

The fighter is characterized by high stability in any position of the landing gear, flaps and during climbing. The effort on the handle is negligible. They increase as the aircraft makes a deep turn. The rudder direction is considered satisfactory, but it may decrease as a result of the low speed at which the La-5FN fighter is moving. The controllability of guns in such conditions is simple. When the rudder is deflected, the nose of the aircraft is raised or lowered. These oscillations, also known as the Dutch pitch, are corrected by the movement of the rudder.

Flight end

The value of 200 km/h was considered optimal for the speed at which the La-5FN fighter was descending. Landing was carried out at three points. Its implementation was simple on a flat surface. Otherwise, it was difficult to keep the car on the run. The cause of the difficulties was uneven braking of the wheels. Very often, a fighter nods when landing, as a result of which the propeller could be damaged, since this aircraft had a limited distance between it and the ground. Significantly complicated the holding of the fighter pilot and strong gusts of side wind. In such situations, it was impossible to cope using only the steering wheel. Therefore, when landing, they often resorted to wheel braking.

Despiteexisting problems in the design, the La-5FN fighter was one of the best models of Soviet aviation technology, which, among its analogues, provided domestic aircraft with a dominant position in the skies of wartime and made a significant contribution to the cause of victory.