The summer breeze tickled the grass on the airfield's airfield. After 10 minutes, the plane climbed to an altitude of 6,000 meters, where the temperature overboard dropped below –20 °, and the atmospheric pressure became twice as low as at the surface of the Earth. In such conditions, he had to fly hundreds of kilometers in order to then engage in a battle with the enemy. Combat turn, barrel, then - immelman. Frenzied shaking when firing cannons and machine guns. Overloads are somewhat "the same", combat damage from enemy fire …
Aircraft piston engines of the Second World War continued to work in any, sometimes the most severe conditions. To understand what is at stake, turn a modern car upside down and see where the fluid from the expansion tank will flow.
The question about the expansion tank was asked for a reason. Many of the aircraft engines simply did not have expansion tanks and were air-cooled, dumping excess cylinder heat directly into the atmosphere.
Alas, not everyone adhered to such a simple and obvious path: half of the fleet of WWII fighters had liquid-cooled engines. With a complex and vulnerable “water jacket”, pumps and radiators. Where the slightest hole from a shrapnel could be fatal to the plane.
The emergence of liquid-cooled motors was an inevitable consequence of the pursuit of speed: a decrease in the cross-sectional area of the fuselage and a decrease in the drag force. Sharp-nosed swift "Messer" and slow-moving I-16 with a blunt wide nose. Like that.
No not like this!
First, the rate of heat transfer depends on the temperature gradient (difference). The cylinders of air-cooled motors during operation were heated up to 200 °, while the max. the temperature in the water cooling system was limited by the boiling point of ethylene glycol (~ 120 °). As a result, there was a need for a bulky radiator, which increased drag, leveling the apparent compactness of water-cooled motors.
Further more! The evolution of aircraft engines led to the emergence of "double stars": 18-cylinder air-cooled engines of hurricane power. Placed one behind the other, both cylinder blocks received a fairly good airflow, at the same time, such an engine was placed within the fuselage section of a conventional fighter.
Water-cooled engines were more difficult. Even taking into account the V-shaped arrangement, placing such a number of cylinders within the length of the engine compartment seemed very problematic.
Finally, the efficiency of the air-cooled motor has always been somewhat higher, due to the absence of the need for power take-off to drive the pumps of the cooling system.
As a result, the fastest fighters of World War II were often not distinguished by the grace of the "sharp-nosed Messerschmitt." However, the speed records they set are amazing even in the age of jet aircraft.
Soviet Union
The winners flew fighters of two main families - Yakovlev and Lavochkin. “Yaks” were traditionally equipped with liquid-cooled motors. "La" - air.
At first, “Yak” was the leader. One of the smallest, lightest and most agile fighters of the Second World War, the Yak proved to be ideally suited to the conditions of the Eastern Front. Where the bulk of air battles took place at altitudes less than 3000 m, and their maneuverability was considered the main combat quality of fighters.
By the middle of the war, the design of the Yaks had been perfected, and their speed was not inferior to American and British fighters - much larger and more technically sophisticated machines with engines of fantastic power.
The record among Yaks with a serial engine belongs to Yak-3. Various modifications of the Yak-3 developed a speed of 650 … 680 km / h at an altitude. The figures were achieved using the VK-105PF2 engine (V12, 33 liters, takeoff power 1290 hp).
The record was the Yak-3 with the experimental VK-108 engine. After the war, it reached a speed of 745 km / h.
Ahtung! Ahtung! In the air - La-5.
While the Yakovlev Design Bureau was trying to solve with the capricious VK-107 engine (the previous VK-105 by the middle of the war had exhausted its reserves of increasing power), the La-5 star rose rapidly on the horizon. The new fighter of the Lavochkin Design Bureau, equipped with an air-cooled 14-cylinder "double star".
In comparison with the lightweight, “budget” Yak, the mighty La-5 became the next stage in the careers of the famous Soviet aces. The most famous pilot of the La-5 / La-7 was the most successful Soviet fighter Ivan Kozhedub.
The pinnacle of the Lavochkin's evolution during the war years was the La-5FN (forced!) And its even more formidable successor La-7 with ASh-82FN engines. The working volume of these monsters is 41 liters! Takeoff power 1850 HP
It is not surprising that the "blunt-nosed" Lavochkin were in no way inferior to the Yaks in their speed characteristics, surpassing the latter in take-off weight, and as a result - in firepower and aggregate combat characteristics.
The speed record for fighters of its family was set by the La-7 - 655 km / h at an altitude of 6000 m.
It is curious that the experienced Yak-3U, equipped with an ASh-82FN engine, developed a higher speed than its “sharp-nosed” brothers with liquid-cooled motors. Total - 682 km / h at an altitude of 6000 m.
Germany
Like the Red Army Air Force, the Luftwaffe was armed with two main types of fighter: "Messerschmitt" with a liquid-cooled engine and "Focke-Wolf" air-cooled.
Among Soviet pilots, the most dangerous enemy was considered the Messerschmitt Bf 109, conceptually close to the light maneuverable Yak. Alas, despite all the Aryan genius and new modifications of the Daimler-Benz engine, by the middle of the war the Bf.109 was completely outdated and required immediate replacement. Which had nowhere to come from. And so the war was overshadowed.
In the Western theater of operations, where air battles were fought mainly at high altitudes, heavier fighters with a powerful air-cooled engine became famous. It was much more convenient and safer to attack the orders of strategic bombers on the heavily armored Focke-Wolves. They, like a knife in butter, plunged into the orders of the "Flying Fortresses", destroying everything in their path (FW.190A-8 / R8 "Shturmbok"). Unlike light "Messerschmitts", whose engines died from one hit of a 50-caliber bullet.
Most of the Messerschmitts were equipped with 12-cylinder Daimler Benz engines of the DB600 line, extreme modifications of which developed take-off power in excess of 1500 hp. The fastest serial modifications reached a maximum speed of 640 km / h.
If everything is clear with the Messerschmitts, the following story happened with the Focke-Wolfe. The new radial-powered fighter performed well in the first half of the war, but by the beginning of 1944 the unexpected happened. The German super-industry has not mastered the creation of new radial air-cooled engines, while the 14-cylinder BMW 801 has reached the “ceiling” in its development. Aryan uber designers quickly found a way out: originally designed for a radial engine, the Focku-Wolfe fighter ended the war with liquid-cooled V-engines (the aforementioned Daimler-Benz and the stunning Jumo-213).
Equipped with the Jumo-213 Focke-Wolves, the D modifications have reached great heights, in every sense of the word. But the success of the "long-nosed" FW.190 was by no means connected with the radical advantages of the liquid cooling system, but with the banal perfection of the new generation engines, in comparison with the outdated BMW 801.
1750 … 1800 HP on takeoff. Over two thousand "horses" when injected into the cylinders with Methanol-Wasser 50!
Max. the speed at high altitudes for the Focke-Wulfs with an air-cooled engine ranged around 650 km / h. The last of the FW.190s with a Jumo 213 engine could briefly develop speeds of 700 km / h or more at high altitudes. Further development of the Focke-Wolf, Tank-152 with the same Jumo 213 turned out to be even faster, developing 759 km / h at the border of the stratosphere (for a short time, using nitrous oxide). However, this outstanding fighter appeared in the last days of the war and its comparison with honored veterans is simply incorrect.
United Kingdom
The Royal Air Force flew exclusively on liquid-cooled engines. This conservatism is explained not so much by loyalty to tradition as by the creation of the extremely successful Roll-Royce Merlin engine.
If you put one "Merlin" - you get "Spitfire". Two - Mosquito light bomber. Four Merlin - strategic Lancaster. A similar technique could have been used to obtain a Hurricane fighter or a Barracuda carrier-based torpedo bomber - more than 40 models of combat aircraft for various purposes.
Whoever said anything about the inadmissibility of such unification and the need to create highly specialized equipment, sharpened for specific tasks, such standardization only benefited the Royal Air Force.
Each of the listed aircraft could be considered the standard of its class. One of the most powerful and elegant fighters of the Second World War, the Supermarine Spitfire was in no way inferior to its peers, and its flight characteristics each time turned out to be higher than that of its counterparts.
The extreme modifications of the Spitfire, equipped with an even more powerful Rolls-Royce Griffin engine (V12, 37 liters, liquid cooling), had the highest rates. Unlike the German "wunderwaffe", the British turbocharged engines had excellent altitude characteristics, could produce over 2000 hp for a long time. ("Griffin" on high-quality gasoline with an octane rating of 150 produced 2200 hp). According to the official data, "Spitfire" Subseries XIV developed a speed of 722 km / h at an altitude of 7 kilometers.
Hawker tempest
In addition to the legendary Merlin and the lesser known Griffin, the British had another 24-cylinder supermotor, the Napier Saber. The Hawker Tempest fighter equipped with it was also considered one of the fastest fighters of British aviation at the final stage of the war. The record he set at high altitude was 695 km / h.
USA
“Captains of Heaven” used the widest range of fighter aircraft: Kittyhokes, Mustangs, Corsairs … But in the end, all the variety of American aircraft was reduced to three main engines: Packard V-1650 and Allison V-1710 water cooled and monstrous "double star" Pratt & Whitney R-2800 air-cooled cylinders.
The 2800 index was assigned to it for a reason. The working volume of the "double star" was 2800 cubic meters. inches or 46 liters! As a result, its power exceeded 2000 hp, and in many modifications it reached 2400 … 2500 hp.
The R-2800 Double Wasp became the fiery heart for the Hullcut and Corsair carrier-based fighters, the Thunderbolt fighter-bomber, the Black Widow night fighter, the Savage carrier-based bomber, the A-26 Invader land-based bombers and B-26 "Marader" - about 40 types of combat and transport aircraft!
The second Allison V-1710 engine did not gain as much popularity, nevertheless, it was used in the construction of the mighty P-38 Lightning fighters, also in the family of the famous Cobras (the main fighter of the Lend-Lease). Equipped with this engine, the P-63 "Kingcobra" developed at an altitude of 660 km / h.
Much more interest is associated with the third Packard engine V-1650, which, on closer inspection, turns out to be a licensed copy … of the British Rolls-Royce Merlin! The enterprising Yankees only equipped it with a two-stage turbocharging, which made it possible to develop a power of 1290 hp. at an altitude of 9 kilometers. For such heights, this was considered an incredible great result.
It was with this outstanding engine that the fame of the Mustang fighters was associated. The fastest American fighter of the Second World War developed at an altitude of 703 km / h.
The concept of a light fighter was genetically alien to the Americans. But the creation of large, well-equipped aircraft was hampered by the basic equation of aviation. The most important rule, according to which it is impossible to change the mass of one element, without affecting the rest of the structural elements (provided that the initially specified performance characteristics are preserved). Installing a new cannon / fuel tank will inevitably lead to an increase in wing surface area, which, in turn, will cause a further increase in the mass of the structure. The "weight spiral" will wind until all the elements of the aircraft increase in mass, and their ratio becomes equal to the initial one (before the installation of additional equipment). In this case, the flight characteristics will remain at the same level, but everything rests on the power of the power plant …
Hence - the Yankees' fierce desire to create super-powerful motors.
The Ripablik P-47 Thunderbolt fighter-bomber (long-range escort fighter) had a take-off mass twice that of the Soviet Yak, and its combat load exceeded the load of two Il-2 attack aircraft. By equipping the cockpit “Thunderbolt” could give odds to any fighter of its time: autopilot, multichannel radio station, oxygen system, urinal… 3400 rounds were enough for a 40-second burst of six “Browning” 50 caliber. With all this, the clumsy-looking "Thunderbolt" was one of the fastest fighters of the Second World War. His achievement is 697 km / h!
The appearance of "Thunderbolt" was not so much the merit of the aircraft designer Alexander Kartvelishvili, as the super-powerful double star "Double Wasp". In addition, the production culture played a role - due to the competent design and high build quality, the drag coefficient (Cx) of the thick-fronted Thunderbolt was less than that of the sharp-nosed German Messerschmitt!
Japan
The samurai fought the war solely on air-cooled engines. This has nothing to do with the requirements of the Bushido code, but just an indicator of the backwardness of the Japanese military-industrial complex. The Japanese entered the war in a very successful Mitsubishi A6M Zero fighter with a 14-cylinder Nakajima Sakae engine (1130 hp at altitude). With the same fighter and engine, Japan ended the war, hopelessly losing air supremacy by early 1943.
It is curious that, thanks to the air-cooled motor, the Japanese Zero did not have as low survivability as it is commonly believed. Unlike the same German "Messerschmitt", the Japanese fighter could not be disabled by hitting one stray bullet in the engine.
