During our broadcast on airplanes, a question was asked about aircraft diesel engines. The topic is completely non-ethereal, since there is not much to argue about, but there are interesting moments that have been continued in our days.
Because - here it is, an aviation diesel engine.
In general, only two countries have reached the sensible use of diesel in aviation. Germany and the Soviet Union. God himself commanded the first, since Diesel was German and all developments after his death remained in Germany, but the USSR is a separate and complex issue.
In fact, both countries began to develop the diesel theme not from a good life. There were problems with the motors, the Germans still had a shortage of oil, we had no technology for its normal processing. High-octane gasolines were an unfulfilled dream for the USSR; they fought the entire war on imported high-octane fuel.
Actually, the essentially different problems of the oil plan gave rise to interest in diesel engines. And it was from what.
A huge advantage of a diesel engine was considered the ability to work not on gasoline, but, as they would say now, on alternative fuels. That is, kerosene and diesel fuel. Yes, kerosene of that time could normally be charged into a diesel engine, and the engine chewed it perfectly. Even modern diesel engines are quite capable of using kerosene as a winter fuel in very low temperatures, it is only necessary to add cetane-enhancing additives.
Kerosene was not as flammable as aviation gasoline, and there had been no problems with its distillation from oil since 1746.
The downside is the large mass of the diesel engine compared to the gasoline counterpart.
The result was a situation in which it was a sin not to try to develop motors for aircraft that will run on the fuel that is easier to drive out. It makes sense, isn't it? Especially when there are developments. The Germans shared their recipes in a very friendly way, and work in the USSR also began to boil.
Each country went its own way.
As the work progressed, it became clear that a diesel engine was not an engine for a fighter jet. He came out too unhurried, unable to respond to the demand to quickly increase the turnover. However, this is still relevant now.
Therefore, the Soviet (let's start with us) designers immediately assigned a niche for long-range and heavy bombers for aircraft diesel. Firstly, the planes themselves were large and were not intimidated by the mass of the engine, and secondly, the efficiency, which means the range were the determining factors.
Unlike the Germans, our designers were tasked with removing the maximum possible power of 1300-1500 hp from diesel engines, which was a somewhat fantastic figure. At that time, the country could not create a gasoline engine of such power, but here a diesel engine …
But it was precisely on motors of this power that would be able to accelerate a bomber weighing 13-15 tons to an acceptable speed of 400 km / h and provide a range of 2500-3000 km that Soviet designers were focused on.
Andrei Dmitrievich Charomsky must be considered the main diesel operator of the country.
Under his leadership, the CIAM team (Central Institute of Aviation Motors named after PI Baranov) developed a 900 hp AN-1A diesel engine, which at low (up to 2500 m) altitudes was absolutely not inferior to gasoline engines. The AN-1A became the basis for further development of these engines, having successfully passed tests on the TB-3D bomber.
Then Charomsky was arrested as a pest, and on the basis of the AN-1A they developed two motors, the M-40 (work was carried out at the Kirov plant in Leningrad under the leadership of V. M. Yakovlev) and M-30 ("Sharaga" at the plant number 82 in Moscow under the leadership of S. I. Zhilin and A. G. Takanaev).
The work was carried out in the "top secret" mode, it reached the point of insanity: military representatives, being from another department, could not get access to the motors to control the quality of products. The permits were issued personally by the People's Commissar of the Aviation Industry A. I. Shakhurin.
The development of both engine models was carried out in the direction of maintaining the working volume, cylinder bore and piston stroke in the direction of increasing take-off power and engine altitude. The altitude of the motors was to be provided by two-stage turbochargers, TK-88 on M-40 and TK-82 on M-30. Four turbochargers were installed on each engine.
By 1940, the engines were not finished, but there was little need for them either. Diesel was viewed exclusively as a political engine capable of providing a round-the-world flight of a record aircraft under the control of M. M. Gromov. There was such a project.
The flight did not take place, since they could not achieve the required service life of 100 hours from both engines. Plants and designers were given the task to conduct bench tests by August 1940, and by autumn to install motors on the TB-7 and DB-240 (future Er-2) aircraft for flight tests.
Let's be honest, diesels are overestimated. One gets the impression that the Soviet aviation leadership was expecting some kind of miracle from the engines, since in 1941 a commission met at the Air Force Research Institute, which determined the requirements for a new aircraft under the forced M-40F diesel engines, a bomb load of as much as 6,000 kg !!!
The aircraft being developed was supposed, according to the commission (led by Major General Filin), to carry one FAB-2000 bomb in the bomb compartment, and two (!) On the external sling!
It is difficult to say what was going on in the soul of the designer Eromolaev, but I do not think that everything was radiant there with happiness. For only when 4 ASh-82F engines (1700 hp) were installed on the Pe-8 in 1944, only then the Pe-8, in exceptional cases and over short distances, was able to take 6,000 kg of bombs.
And then 1941 …
Plus, without waiting for the start of testing, Shakhurin's department (NKAP) issued a task to Voronezh aircraft plant No. 18 with an order for the construction of 90 Er-2 aircraft with M-40F diesel engines in 1941, and 800 machines in 1942.
It is clear that all these plans were destroyed by the war. But it is better this way, because they were able to bring the motors to flying condition just before the start of the war.
Only on July 23, 1941, the head of the LII NKAP M. M. Gromov approved the act on testing the Er-2 aircraft with M-40F engines. On tests, the aircraft with diesel engines showed a speed of 448 km / h at an estimated 480 km / h. After the elimination of numerous shortcomings, the machines were given the green light, but the war began, bringing with it the end of diesel aviation.
We are talking about the famous raids on Berlin in August 1941. 8 TB-7 aircraft with M-30 engines were to take part in the operation on August 10. In fact, seven cars took part in the raid, since the eighth crashed during takeoff. Of the remaining seven, ONE (!) Plane returned to its airfield in Pushkin. The rest, alas, were forced to sit in different places precisely because of the failures of the M-30 engines.
Well, as usual with us, all the shortcomings of diesel engines, to which the leadership of the NKAP willingly turned a blind eye to the Berlin fiasco, "suddenly" came to light and became a sufficient reason for the almost complete curtailment of the diesel program. True, at first it was decided to reject the M-40F, and the M-30 was "banned" a little later.
Ermolaev fought for his plane to the last. On August 5, 1941, he addressed a letter to the People's Commissar of the aviation industry, Shakhurin:
"Taking into account the special need of our defense in long-range bombers, we consider it necessary to continue the work of our plant on the creation of aircraft - long-range bombers and we ask you … to give the team of our plant the opportunity to finish the refinement of the Er-2 2M-40F aircraft."
However, the fate of the M-40F was practically decided by the unsuccessful raid of the TB-7 on Berlin. In addition, Kharkov was lost, but even before the loss of the city, the Kharkov Tractor Plant was transferred to the production of V-2 diesel engines and T-34 tanks. And in the fall of 1941, it became impossible to carry out work on the M-40F in Leningrad, since the Germans began a blockade.
If we turn to the historical documents, we can see that the complete set of documentation for diesels by the Ermolaev Design Bureau was transferred to Voronezh in the first half of 1941. However, Plant # 18 assembled aircraft, not engines. Therefore, it was simply unrealistic to quickly establish production of the M-40F in Voronezh. And in 1942, the evacuation of this plant began.
In general, by the beginning of the war, about 200 aircraft diesels of both brands were produced in the USSR. First of all, the motors were installed on TB-7, and secondly, on Er-2. The results were disappointing: during the tests, only 22% of the M-40 engines and 10% of the M-30 engines were able to operate for more than 50 hours, while approximately every third diesel engine failed without having served even 10 hours.
In fact, the aircraft diesel program was curtailed, the released Er-2 was transferred to the AM-35 and AM-37.
But Ermolaev and Charomsky did not give up. They really wanted the Air Force to get a long-range bomber. And in 1943, they presented the Er-2 with M-30B engines to the court.
The letter "B" in the name of the engine meant that the supercharging was carried out in a combined way: in addition to the two left turbochargers, Charomsky supplied the diesel with a drive supercharger borrowed from the AM-38 engine. This ensured stable operation of the motor at high flight altitudes.
The empty weight of the vehicle increased to 10325 kg (which is almost one and a half tons more than that of the Er-2 2AM-37), and the maximum take-off (calculated) - up to 17650 kg. The composition of the crew did not change and included a pilot, navigator, gunner and gunner-radio operator.
The tests were carried out in February 1943 by the Air Force Research Institute. The aircraft was tested by engineer-lieutenant colonel N. K. Kokorin and pilots colonel Alekseev and major Lisitsin. According to the pilots' estimates, the aircraft was easy to fly in almost all modes. Its maximum speed, compared to the version with AM-37, decreased to 429 km / h, but the calculated maximum flight range exceeded the originally set for Er-2 and reached a fantastic 5500 km.
The bomber became more tenacious, because kerosene ignited in the cold air extremely reluctantly. The total weight of the armor reached 180 kg, while the pilot received a 15-mm armored back. The upper turret was equipped with an electric drive, which made the shooter's work easier. Now a 360 ° turn was done in just 6 seconds.
In a letter to the head of the Air Force Research Institute, Lieutenant General P. A. Loskutov, dated June 1, 1943, Ermolaev indicated that the new version of his bomber was twice as large as the Il-4 in terms of the number of bombs delivered to the target. In addition, Er-2 had an advantage over Ilyushin's aircraft in flight speed - both at the ground and at altitude. In particular, with a flight range of 3,000 km, the IL-4 could carry 1,000 kg of bombs, and the Er-2 2M-30B could carry 2,000 kg.
There were, however, also disadvantages. Low rate of climb, long takeoff distance, inability to fly without loss of altitude on one engine. The car turned out to be overweight, the engine power was again lacking.
However, there was also such a remark:
“Maintenance of M-ZOB engines by ground personnel in winter and summer is easier than servicing gasoline engines due to the absence of an ignition system and carburetors in the presence of reliably working injection equipment. The fuel equipment (TN-12 fuel pump and TF-1 injectors) installed on the M-ZOB worked reliably and had no defects during the entire test period."
In general, it should be admitted that they could not make a normally working aviation diesel engine in the USSR. Er-2 never took a place in the ranks of combat aircraft, since several dozen equipped with M-30 Er-2 did not make so many sorties during the war.
It cannot be said that all the work was in vain, since the M400 (M-50F-3) engine with a capacity of 800 hp became the follower of the M-30. with. and M-401 (turbocharged) with a capacity of 1000 liters. with. These engines moved from heaven to water and were installed on high-speed vessels "Zarya", "Raketa", "Voskhod" and "Meteor".
The diesel engine on Soviet bombers, alas, did not play any significant role.
Now let's see what the Germans had.
And the Germans had Junkers. Professor Hugo Junkers.
After the end of the First World War, Junkers switched to work on transport and passenger aircraft. With the expansion of production at Junkers in 1923, Junkers Motrenbau GmbH was established, where work began on the creation and production of aircraft engines, including diesel engines.
Junkers has been working on the aircraft diesel for 20 years and has achieved the best results with the Jumo.205 engine.
But the first real aircraft diesel was the Jumo 204, a 740 hp twelve-cylinder diesel engine. This diesel engine was installed on Junkers G24 aircraft and was successfully operated until 1929.
The Jumo 204 diesel proved to be a successful engine that was used on other aircraft as well. The list consists of very famous models: Junkers F.24kay, Junkers Ju.52, Junkers Ju.86, Junkers G.38, Blohm & Voss BV.138.
But the best diesel aircraft engine really can be considered the Jumo.205, the development of which began in 1932. It was one of the few successful diesel aircraft engines in the world. Jumo.205 became the basis for the creation of a whole family of diesel engines.
The engine showed itself excellently under constant load, however, it reacted to a sharp increase or decrease in revolutions, like Soviet motors, with a drop in power or could even stall. Plus, the Jumo.205 could not be called a high-altitude engine: over 5000 meters, engine power dropped sharply by 20-22% and even more.
The engine was used on the following aircraft models: Blohm & Voss BV.138, Blohm & Voss Ha.139, Blohm & Voss BV.222, Dornier Do.18, Dornier Do.26, Junkers Ju.86.
In fact, Junkers diesels were installed on those aircraft that were guaranteed against encounters with enemy fighters. Patrol ocean and sea flying boats, scouts and so on. That is, aircraft that did not require vigorous maneuvering, but required the maximum flight range.
However, despite the excellent economy and, accordingly, excellent range, Jumo.205 diesels did not live up to expectations. They worked well under constant and prolonged load, but they did not tolerate the change in speed, which was required for combat maneuvering. This shortcoming has not been fully overcome.
Plus the Jumo.205 engines required extremely skilled maintenance by specially trained personnel. And if the Luftwaffe could still solve this, then attempts to "land" the Jumo.205 and make the engine a tank engine failed completely. Precisely because the engine was unnecessarily demanding in terms of maintenance.
Despite a decent list of aircraft, several dozen of the total were equipped with diesel engines. And although in the end the interest of the Luftwaffe in diesel engines faded away, Junkers continued to work on improving the Jumo.205 aircraft diesel engine and in 1939 released a high-altitude version - Jumo.207 with two centrifugal superchargers: the first with an exhaust drive, the second with a mechanical drive. and with an intercooler.
The peak of development of Junkers aircraft diesel engines was a truly monstrous thing called Jumo.224. This engine was, in fact, a rhombus of four Jumo.207 engines. 24-cylinder, 48-piston, two-stroke, liquid-cooled diesel engine with opposite piston movement.
This nightmare weighed 2,600 kg and, according to calculations, should have produced 4,400 hp. on takeoff and 3,500 hp. at an altitude of 15 km. The engine was not assembled even for testing, they did not have time. The photos that have come down to us are prototypes.
This, if I may say so, the design was very interested in our engineers after the end of the war. Studies and tests were carried out, but Jumo.224 is the subject of a separate article, but here I will only say that a memo was submitted to the Deputy Minister of the Aviation Industry, Major General IAS M. M. Lukin, in which, after describing the engine and analyzing the capabilities, the following conclusions were made:
Soviet engineers were familiar with the forerunners of Jumo.224, since Jumo.4 and Jumo.205 were purchased and studied in the 30s in the USSR, so our specialists perfectly understood and soberly evaluated their strengths in the production of such motors.
It so happened that the diesel still migrated from heaven to earth. But the reason for this was elementary technical progress, which gave rise to turbojet engines, which eventually replaced both gasoline and diesel engines.
Two countries have been able to build aircraft diesel engines, each with something to be proud of. Diesel was an interesting engine for long-range aircraft, it could well carry transport and passenger aircraft. Perhaps it was the initial mistake - to install diesel engines on combat aircraft, but there is nothing you can do about it.
It cannot be said that we have achieved the same success as the Germans. The designers of the two countries followed different routes, German engineers, perhaps, achieved great success, but: Diesel left them everything. Our engineers went their own way, and Charomsky and his students passed it more than worthily.
