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A Few Words About Six Levers

Features of control of Soviet and German fighters during the Second World War

Denis Belov

As you know, the history of the Great Patriotic War is replete with a wide variety of legends and myths. Some of them disappear or are forgotten over time, but instead of them others immediately appear, sometimes opposite in meaning. In the old days, the generally accepted opinion in our country was the complete technical superiority of the new Soviet fighters, put into service before the war, over enemy vehicles. In the 90s, the pendulum swung in the opposite direction and began to extol the enemy's technique.

How do you find the truth among these mutually exclusive points of view? If it is quite simple to compare the graphs of changes in the maximum speed or rate of climb, then some other criteria are much more difficult to evaluate and compare. Let's try to figure out what usually remains "behind the scenes" - the control features of Soviet and German aircraft. The importance of this parameter is undoubted, because the less the pilot is distracted by the control of the propeller-driven group, trims, flaps, etc., the more attention he can pay to the air situation, and accordingly, his chance of noticing the enemy and attacking in time increases, or he can safely escape from -under the blow.

The magazine "Airhobby" No. 1 -1993 published an article "La-5 through the eyes of the Luftwaffe", with a report from the German test pilot Hans-Werner Lerche on the tests of the captured La-5FN. In particular, it said: “Control of the pitch of the propeller, radiators, blinds, trimmers, etc. - manual with the help of various rods. This leads to distraction of the pilot's attention and a decrease in flight performance during air combat. " Then there was an editorial comment: "(for example, for a sharp increase in flight speed, the pilot of the La-5 had to move six levers in succession - approx." Air hobby ")".

Let's try to figure out what the fighter pilot of the 40s of the last century had to regulate during the battle?

The most important parameter that determines the characteristics of an aircraft, in addition to engine boost (gas) and propeller speed, is the position of the propeller blades relative to the incoming air flow, called the propeller pitch. Most fighters of that time used variable pitch propellers (VISH).

What is VISH for? Engine power is controlled by the carburetor throttle valve controlled by the throttle lever. However, the power also depends on the resistance to rotation of the screw. If it is "heavy" (that is, with a lot of resistance), then, despite giving full throttle, the engine will not reach its rated speed and it will not be possible to obtain rated power. The speed and power can be changed not only by throttling the motor, but also by changing the external load on the shaft - by "lightening" and "tightening" the screw.

For flight at maximum speed, climb, takeoff, etc., it is advantageous to set the maximum allowable rpm, since maintaining them, the engine gives the propeller full power. But there is no need to maintain maximum rpm when flying at not full power, since the engine, operating at low power with high rpm, has a large specific fuel consumption, and the propeller has a reduced efficiency, since its blades operate with very low angle of attack.

Step control on Soviet Yak, MiG and La fighters was carried out using an automatic constant speed controller (RPO). Thus, the pilot did not have the need to manually change the propeller pitch by moving the handle, this was done by the RPO, and the pilot only set the required rpm. The exception was the dive mode. To achieve the highest speed, it is necessary to dive with full throttle, setting the speed below the nominal by 200-400 rpm. To reduce the speed, on the contrary, remove the throttle and "lighten" the screw.

RPO was a hydraulic mechanism. The change in the angle of the blades was carried out due to the oil pressure taken from the engine crankcase and pumped into the propeller hub by a special pump. *

On the German Bf 109 fighter, automatic "step-gas" control was also used, but its VDM propeller had not a hydraulic, but an electric mechanism for changing the setting angle of the blades.

Which system is better? The clear advantage of electric step control was its non-susceptibility to spinning and higher resistance to damage - the generator and electrical wiring are less vulnerable than the oil system. In addition, the hydraulic control of the variable pitch propeller was analog, the control action changed continuously, but with some delay, which led to a small overshoot. The control actions on the blades in the electrically controlled system had a shorter time delay.

Air battles were fought, as a rule, at maximum engine power. In this mode, the maximum thrust taken from the propeller was achieved at the maximum permissible engine speed, that is, with a completely "lightweight" propeller. The pilot moved the RPO handle forward all the way and no longer cared about changing the pitch: the RPO itself kept the RPM in a given mode (with the exception of the RPM spinning). The German pilots did the same.

Therefore, the statement, which is found here and there, that on Soviet aircraft, unlike German ones, the pilots had to constantly manually control the propeller pitch is incorrect.

On the Focke-Wulf FW 190, a hydraulic step control system was installed, included in a unified automatic engine control system (the so-called "command post" - Kommandogerat). Kommandogerat also regulated the on / off at a given height of the second stage of the supercharger and the operation of the fuel (altitude) corrector. In fact, the FW 190 pilot controlled all the parameters of the propeller group with only one throttle stick.

Aircraft engines during the Second World War, as a rule, were equipped with forcing systems (temporary increase in power). But if on our cars the inclusion of the afterburner consisted only in increasing the boost, then on German cars, starting from 1942-43, various additional systems (MW-50, GM-1) were often used, which injected a water-methanol mixture or nitrous oxide into the engine cylinders. Moreover, they were included with a number of restrictions. Failure to comply with these modes led to engine failure, but even with normal operation, fuel consumption increased sharply, and the engine life significantly decreased. In addition, when the additional systems were turned on, the motor went to the forced mode not instantly, but after 30-60 seconds.

On German aircraft, the use of the altitude corrector and the switching of the supercharger stages were automated. It is because of a malfunction of the supercharger control system (possibly due to a microcrack in the aneroid box of the barometric altitude indicator) that the captured Bf 109F-2 during tests at the Air Force Research Institute did not show real characteristics at high altitudes, misleading our specialists. Subsequently, similar systems began to be used by the Allies, although not on all machines. Until the end of the war, Soviet pilots turned on the second speed of the supercharger manually, following the readings of the altimeter.

The next most important parameter is the motor temperature. Without a doubt, control here was more convenient on German aircraft - already from 1941, automatic radiator flap control began to be used on the Bf 109F. Later, similar devices appeared on the British "Spitfires" and on some American fighters. And the pilot of the Yak-1, Yak-7 or LaGG-3 had to do it manually, which is really inconvenient. Inexperienced pilots often overheated the engine without opening the radiator flaps in time.

Only from the summer of 1944, automatic temperature control devices ART-41, copied from the German model, appeared on Yakovlev's fighters, but on Lavochkin's machines with air-cooled motors, the pilot still had to manually maintain the temperature regime.

This is what a fighter pilot, a veteran of the Patriotic War, says about this D.A. Alekseev: “You do something during the whole flight, every minute you work. Everything is mechanical, on rods. During the flight, the pilot constantly adjusted the cooling of the engine, these are the louvers in front, and even the side flaps. Plus - an oil cooler, there was also a flap. You go to the set - you twist it for cooling, if you go down - twist it back, you keep the heat ”. When it's already here to watch the air ... **

There is a statement that the automatic control of the radiator increases the maximum speed of the aircraft, since fully open doors reduced the speed of the aircraft by 30-35 km / h. However, the automatic regulator also opens the radiator flaps when the engine is running at maximum power. In fact, automatic flap control reduces the load on the pilot, reduces the risk of overheating, but it will not add speed.

The engine cooling system used on the FW 190A, F, and G fighters stands apart. It was a 12-blade fan rotated from a crankshaft with an overdrive. At low speeds, it improved cooling, but there was no cooling regulation. At a constant number of fan revolutions at high speeds, the flow was decelerated, which reduced the maximum speed; moreover, part of the engine power was spent on rotating the fan.

The issue with oil cooling was also resolved in a very peculiar way. The oil system of the FW 190 A / F / G differed from the usual ones not only in the arrangement and design of the units, but also in the principle of operation. There were no oil cooler flaps regulating the temperature. Oil from the engine went into the tank, and from it into the radiator, located in a ring-like manner inside the front of the engine hood around the entire perimeter, forming a common unit with the front armor rings of the hood. The oil was cooled by a fan, which simultaneously cooled the engine.

Of course, the armor to some extent protected the oil cooler and oil tank from combat damage, but 3-5 mm armor protection can hardly be called reliable, and the affected area has increased several times compared to a conventional oil cooler. As a result, the air-cooled engine was deprived of one of its main advantages - reliability, and the weight of the armored rings and the fan with the drive negated the advantages over the conventional cooling system with tilting flaps.

Without a doubt, two radiators recessed into the lower plane of the Bf 109 wing were a good solution - they created minimal aerodynamic drag, and if one of them was damaged, the pilot could turn it off with a special shut-off valve and continue the flight. The "box" of the radiator, located under the fuselage of Yakovlev's fighters, created more resistance, and during a forced landing without a landing gear, the radiator would inevitably fail.

Let's talk about trims and flaps. Criticizing Lavochkin for the use of rods and cables in the La-5FN control system, they usually "forget" about the method of flap control on the Bf 109. This system can hardly be called perfect even for its time: on the left hand side there were two wheels on board the cockpit, one of which was with using a chain drive, it controlled the flaps (for full release it was necessary to make four turns), the other controlled the angle of the stabilizer.

The trim control on many airplanes of that time was similar, but flaps were already released and retracted by pneumatic, hydraulic or electric drive. This archaic system existed unchanged on all modifications of the Messerschitt from 1936 to 1945.

For comparison, on the FW 190, the stabilizer angle, flaps, extension and landing gear retraction were controlled electrically, and the flaps had three fixed positions (0 °, 10 °, 60 °), each of which was set by simply pressing one of the three corresponding buttons.

Let us now return to the beginning of our article and see how true the statement of the "Air Hobby" magazine about the need to move six levers in sequence to increase the speed of the La-5 fighter is true. Here is an excerpt from the "INSTRUCTIONS TO THE FLYER ON OPERATING THE AIRCRAFT La-5 WITH M-82 MOTOR", published in 1942:

Summing up our brief overview, we can conclude that the control of Soviet fighters in general was somewhat more difficult than German ones (especially - FW 190). However, this complexity was not so significant as to have a serious impact on the outcome of air combat.

* Approx. admin. - For a long time it was not possible to complete the epic with the simplification of the M-82FN engine control. Back in 1942, one La-5 was equipped with an experimental M-82A engine with an 82-VG hydraulic unit for combined propeller pitch and gas control, which replaced 2 levers. The old control was not only inconvenient, but also led to excessive fuel consumption - even an experienced pilot could not always clearly correlate the optimal positions of the "gas" and the propeller pitch. Ground testing of joint management at plant No. 21 was delayed due to the lack of specialists, and the car was transferred to the LII. Flights on it began only in the summer of 1943. The unit had many shortcomings, but all of them were removable. It was more difficult to link the 82-VG and the R-7 speed controller. For this, it was necessary to improve not only the control, but also the motor itself. The reference M-82F with "82-VG" began to be tested in August 1943, and at the beginning of the next year, the experienced M-82FN was converted under joint control, with which La-5 No. 392116161 passed State tests in July. Since August 1944, the 82-VG unit was introduced into the series.

** The same Alekseev (see the link) about control in air combat - "Everything was limited by the temperature of the cylinder heads - 220 ° C. If you managed not to exceed the temperature of the heads, that is, the engine did not overheat, then at least spend the whole flight on the "handles all the way." grabbed and went to the “pretzel” to “write out.” And, until he got out of the fight, he didn’t take his other hand off the handle. And normally, nothing happened to the engine. that during the battle I was not distracted by anything in the cockpit. One battle, I remember 10-12 minutes, like this, at full throttle, we were “spinning”. "

and on the echelon - "... the transparency of the lantern was normal, but when you look through it towards the sun, the" plex "glare gave, and this interfered, because the most dangerous enemy attack was from the sun Sometimes the closed lantern fogged up, which is dangerous for the same reason for the reduced view. Well, I was the wingman in most of the sorties. The wingman is the shield of the pair, therefore, the first attack of the enemy is on me. I was the first to see the enemy. So I used it - I opened the flashlight. As for comfort, I can say that then they simply did not think about it. All the flight you do something, every minute work. Everything is mechanical, on rods. During the flight, pilot constantly

When meeting with an enemy, in order to achieve maximum flight speed, you must:

1. Remove the altitude corrector sector.

2. When the flight altitude is more than 3500 m, turn on the second speed of the supercharger.

3. Give full throttle, while the number of revolutions per minute should be equal to 2400.

4. Close the canopy, which will increase the speed by 10 km / h.

5. Close the hood flaps and the oil cooler flap to the “downstream” position (when fully opened, the maximum speed decreases by 30-35 km / h).

6. Switch on the afterburner (use the afterburner continuously at Рк equal to 1140 mm Hg, no more than 5 minutes is allowed).

7. Monitor the thermometer readings, not allowing the cylinder head temperature to rise above 215 ° C, and the oil temperature above 125 ° C.

Items 4 and 5 are optional, because the lamp could have been closed in advance, and the hood and radiator flaps were already installed "downstream". It is not necessary to use the altitude corrector when patrolling at low and medium altitudes, and when climbing, the blower must be turned on once. On later models La-5F and FN, the restrictions on the use of the afterburner were removed.

What remains? Give full throttle, having previously lightened the screw with the RPO knob and monitor the temperature. In general, no "six levers". And the pilot of the Yak before the battle, in general, did only one operation - he simultaneously moved the boost and RPO handles forward to the stop. And that's it!

Summing up our brief overview, we can conclude that the control of Soviet fighters in general was somewhat more difficult than German ones (especially - FW 190). However, this complexity was not so significant as to have a serious impact on the outcome of air combat.

* Approx. admin. - For a long time it was not possible to complete the epic with the simplification of the M-82FN engine control. Back in 1942, one La-5 was equipped with an experimental M-82A engine with an 82-VG hydraulic unit for combined propeller pitch and gas control, which replaced 2 levers. The old control was not only inconvenient, but also led to excessive fuel consumption - even an experienced pilot could not always clearly correlate the optimal positions of the "gas" and the propeller pitch. Ground testing of joint management at plant No. 21 was delayed due to the lack of specialists, and the car was transferred to the LII. Flights on it began only in the summer of 1943. The unit had many shortcomings, but all of them were removable. It was more difficult to link the 82-VG and the R-7 speed controller. For this, it was necessary to improve not only the control, but also the motor itself. The reference M-82F with "82-VG" began to be tested in August 1943, and at the beginning of the next year, the experienced M-82FN was converted under joint control, with which La-5 No. 392116161 passed State tests in July. Since August 1944, the 82-VG unit was introduced into the series.

** The same Alekseev (see the link) about control in air combat - "Everything was limited by the temperature of the cylinder heads - 220 ° C. If you managed not to exceed the temperature of the heads, that is, the engine did not overheat, then at least spend the whole flight on the "handles all the way." grabbed and went to the “pretzel” to “write out.” And, until he got out of the fight, he didn’t take his other hand off the handle. And normally, nothing happened to the engine. that during the battle I was not distracted by anything in the cockpit. One battle, I remember 10-12 minutes, like this, at full throttle, we were “spinning”. "

and on the echelon - "... the transparency of the lantern was normal, but when you look through it towards the sun, the" plex "glare gave, and this interfered, because the most dangerous enemy attack was from the sun Sometimes the closed lantern fogged up, which is dangerous for the same reason for the reduced view. Well, I was the wingman in most of the sorties. The wingman is the shield of the pair, therefore, the first attack of the enemy is on me. I was the first to see the enemy. So I used it - I opened the flashlight. As for comfort, I can say that then they simply did not think about it. All the flight you do something, every minute work. Everything is mechanical, on rods. During the flight, pilot I constantly adjusted the cooling of the engine, these are the blinds in front, and even the side flaps, large and small. Plus - an oil cooler, there was also a flap. You go to the set - you turn on the cooling, if you go down - you turn it back, you keep the heat. Plus - the rudder and rudder trim tabs the depths us. Plus - you look around with all your eyes, which means "snake" and rolls, you also work with your hands and feet. And also - the propeller pitch, altitude corrector, throttle sectors. Not a single second of rest. And suddenly a respite is "formed", then you try to adjust the radio ... "

Bibliography

  • "Aviamaster" / №8 2006 /