In the mid-thirties, the development of active-rocket artillery shells (ARS) began in Germany. Already in 1936, Dr. Wolf Trommsdorff made an original design for such an ammunition. He proposed to build a projectile based on a ramjet engine (ramjet). According to the calculations of the scientist, such an ammunition was supposed to show outstanding combat characteristics.
Theoretical basis
V. Trommsdorff's project was based on the developments of a group of gas dynamics scientists led by Klaus Osvatic. In the early thirties, they proposed and calculated new versions of a ramjet engine with a tubular body and a central body passing through the entire internal cavity.
V. Trommsdorff became interested in such ramjet designs and found practical use for them. After a certain refinement, the engine with new units could become a full-fledged ARS for use in barrel artillery.
In October 1936, the first documentation on this proposal was sent to the Armaments Directorate. The command showed interest, and the scientist received his own laboratory for conducting experiments.
E-series start
The first years were spent on additional research and design. It was only in 1939 that V. Trommsdorff carried out the first firing using an experienced 88 mm E1 projectile. It is curious that the first model of the ARS with a ramjet engine was seriously different in design from the later ones.
The E1 received a hollow cylindrical body with a frustoconical head fairing. The opening in the fairing served as an air intake; in the central part of the body was placed a holding device with a checker of powdered fuel. A nozzle was provided in the bottom part. The warhead was absent due to the lack of sufficient volumes. The product weighed 4.7 kg, of which 0.3 kg was fuel.
The muzzle velocity did not exceed 800 m / s. On the trajectory, due to the operation of the ramjet engine, the product gained speed and accelerated to 910-920 m / s. The tests confirmed the fundamental possibility of creating an ARS with a ramjet engine.
In 1942, as part of the development of new designs, the E1 projectile was again used for testing. Instead of charging solid fuel, a container for liquid fuel with a nozzle was placed in it. The mixture of diesel fuel and carbon disulphide again confirmed the possibility of acceleration from its own engine.
Caliber growth
The first versions of the Trommsdorf APC used compressed fuel and were similar in design to the original E1. The development of the line at first was carried out only by scaling the original design and its corresponding modifications. At the same time, there was an increase in the main characteristics.
So, in 1940, they tested the APC E2 - an enlarged 105-mm version of the basic product. ARS weighed 9.6 kg and carried 900 g of solid fuel. On the trajectory, its speed reached 1050 m / s. Soon, an E3 shell of 122 mm caliber appeared with similar flight data.
In 1942-44. tested several variants of the 150 mm projectile under the designation E4. Apparently, the APC E1 scheme had certain drawbacks, because of which it had to be abandoned in favor of a more efficient one. According to the search results, the most successful was K. Osvatich's scheme with an oblong central body passing through the entire structure of the projectile and its ramjet engine.
Product E4
The resulting E4 had a cylindrical body. The cone of the central body protruded through the frontal air intake. The latter was longer than the main body and had a variable cross-section. The body and the central body were connected using a set of blades set at an angle and giving the projectile rotation. The body contained a tank for a mixture of diesel fuel and carbon disulfide (according to other sources, only for carbon disulfide), as well as nozzles for removing fuel into the combustion chamber.
The shell with a diameter of 150 mm and a length of 635 mm weighed 28 kg. The warhead was absent, although in one of the variants of the project a small volume was provided for a charge of limited power.
An experienced cannon sent him flying at a speed of 930 m / s. Then the ramjet engine provided acceleration up to 1350-1400 m / s. According to various sources, tests of the E4 projectile with such characteristics took place only at the end of 1944 or at the beginning of 1945.
New series
In 1943 W. Trommsdorff completed work on the first large-caliber ARS intended for high-power artillery. It was a 210 mm C1 shell. In its design, it largely resembled the E4 product, but there were significant differences.
For C1, a cylindrical body (possibly a narrowing of the bottom) with leading belts was created, inside which a large central body with anterior and posterior cones was placed. In the body there was a tank for diesel fuel - this time they refused carbon disulfide. With a mass of 90 kg, the projectile carried 6 kg of fuel. The warhead was again absent due to the overly dense layout.
When firing from existing 210-mm guns, the C1 projectile could accelerate in flight to 1475 m / s. During the tests, it was possible to execute a shot at a distance of 200 km. However, the shooting accuracy left much to be desired.
Superguns for superguns
At the final stage of the war in Germany, the GR.4351 solid-propellant rocket projectile was developed for the 280-mm Krupp K5 railway gun. Dr. Trommsdorff set about developing an alternative to this ammunition. His ARS with a ramjet was supposed to surpass all other projectiles in terms of firing range.
The 280 mm ammunition was developed on the basis of the C1 and called the C3. It had a similar design, but was larger and heavier. With a length of 1.35 m, it weighed 170 kg and carried 16.3 kg of diesel fuel. For the first time in Trommsdorff's projects, a projectile received a warhead. However, the charge weighed only 9 kg - just over 5% of the total mass of the ARS.
The calculated maximum speed of the C3 exceeded 1850 m / s. The firing range is about 350 km. With the help of such a projectile, Germany could attack different targets at a great depth of enemy defense. However, the promising ARS never made it to the test. The project came too late and did not have time to reach the landfill within a reasonable time frame.
Based on the design of the C3 projectile, it was proposed to create several new ammunition with higher characteristics. The C-series was also planned to include the APC in calibers 305, 380 and 405 mm. They were supposed to deliver a charge of 15 to 53 kg over a distance of hundreds of kilometers.
In my dreams there was a 508-mm projectile with a nuclear warhead. Also, based on the existing ramjet designs, it was proposed to create several missiles with different flight ranges and combat loads. However, the outcome of the war was a foregone conclusion, and all these projects had no chance of reaching even a full-fledged design.
Post-war period
In 1945, V. Trommsdorff's laboratory was in the Soviet zone of occupation. German specialists headed by a doctor ended up in KB-4 at the Research Institute "Berlin". Together with Soviet scientists, they had to complete the development of existing projects and bring them, at least, to testing.
KB-4 under the leadership of N. A. Sudakova successfully completed the 280-mm ARS project and manufactured models for blowing in a supersonic wind tunnel. There is no information on further work. Perhaps at this stage, Soviet scientists and the military considered the idea of an ARS with a ramjet engine unpromising and abandoned further work.
According to some sources, in 1946 Wolf Trommsdorff died in a plane crash, but this is not true. In the mid-fifties, the scientist and his colleagues went home. In 1956, a symposium was held in Munich dedicated to German developments during the war in the field of jet propulsion. One of the speakers was Dr. Trommsdorff, who spoke about all his projects since E1.
However, the scientist was unable to continue work on his ARS projects. Shortly after the symposium, V. Trommsdorff died of a long illness. His developments on the topic of ramjet engines interested scientists and designers, and some of them were even used in real projects.
Nevertheless, the idea of an ARS with a ramjet engine did not receive support and was actually forgotten for several decades. Later, from time to time, various projects of projectiles with an unusual propulsion system were proposed, but none of these projects reached full implementation. A number of different-purpose missiles with ramjet engines turned out to be more successful.
Thus, for Hitler's Germany, V. Trommsdorff's projects - like many other developments - turned out to be a useless waste without a real result. All useful developments and technologies, even those requiring long and complex development and improvement, went to the winners. Although they did not copy and use the German projects in their original form.
