German scientist and designer Alexander Martin Lippisch is primarily known for his numerous and not always successful projects in the field of aviation. At the same time, he managed to work in other areas. So, at the very end of 1944, A. Lippisch and his colleagues at the Luftfahrtforschungsanstalt Wien (LFW) Institute presented the German command with an interesting concept of an active-rocket artillery shell.
Origins and ideas
It should be recalled that the development of active-rocket projectiles (ARS) in Nazi Germany started back in 1934 and a few years later gave real results. Early projects involved equipping the ARS with its own powder engine. It provided additional acceleration after exiting the barrel and increased the firing range.
Already in 1936, the original version of the ARS was proposed by the designer Wolf Trommsdorff. He planned to use a ramjet engine (ramjet) together with the tail compartment with a powder checker. The idea of a direct-flow ARS received support from the military, and in a few years the engineer managed to create samples suitable for testing. Nevertheless, V. Trommsdorff's project did not give real results. His ARS were never able to get to the front.
In 1944, the LFW remembered the idea of an ARS with a ramjet engine, and immediately began to study it. In the shortest possible time, the pros and cons of such products were identified, the development paths were determined, and the first prototypes were created and tested. By the end of the year, the project documents were submitted to the command.
Projectile family
A. Lippisch's report actually revealed the issues of creating a whole family of ARS with different design features. According to the LFW project, it was possible to create eight variants of the projectile with various advantages. The eight concepts were based on several basic ideas - they were combined in different ways with different results.
Calculations showed that a ramjet for a projectile can have a different design. It could use liquid or powder fuels. Good characteristics made it possible to obtain the simplest coal powder - a cheap and affordable fuel. Various flammable liquids have been studied. The possibility of creating a combined propulsion system with components on liquid and solid fuels was not excluded.
The first version of the ARS was a simple blank with an internal channel forming a ramjet engine. In the center of this cavity there was a channel for a coal powder checker. To eject such a projectile from a cannon, a special pallet was required to be put on the bottom with a nozzle.
For stabilization in flight, the ARS could be rotated around its axis by means of the rifling of the barrel or with the help of stabilizers deployed in flight. An option was also offered with ridges or blades on the head fairing.
The presence of a through channel and a pallet complicated the design and made it difficult to operate the APC. To exclude it, LFW developed a new version of the ammunition architecture. It provided for the abandonment of the traditional bottom nozzle and the use of a different ramjet layout.
This version of the ARS had to consist of two parts. The main body was a body of revolution with a closed bottom part without a nozzle. A cavity for liquid or powder fuel, as well as means for its supply, was provided inside. The head fairing received a frontal air intake, and channels or cavities were provided inside it. The fairing was put on the body with a gap.
Through the intake hole, air was supposed to get inside the projectile and ensure the combustion of fuel in its cavity. The gaseous products of combustion under the pressure of the incoming air had to enter the cavity of the fairing, and then exit through the annular gap, which acts as a nozzle.
Such a complex ramjet design had several advantages. Blowing the projectile with hot gases improved aerodynamics and could give some gain in flight range. The fairing could be moved along the APC axis, changing the width of the nozzle gap and, accordingly, the ramjet thrust. The possibility of creating controls for this gap was not excluded.
Inside the main body of the ARS with a separate fairing, it was possible to place a powder checker, powdered coal or a tank with liquid fuel. Several options were considered for storing and supplying fuel to the chamber.
Of particular interest are the ARS options, which are more like missiles. In the head part of such a product, it was proposed to place a ramjet engine running on liquid fuel, and in the tail - a conventional solid propellant rocket. With the help of the latter, the launch was carried out with a guide, and the liquid ramjet engine was supposed to provide acceleration in flight.
For obvious reasons, most of the internal volume of ARS should have been occupied by the ramjet and its fuel. However, there was some room inside the case to accommodate the explosive charge and the fuse. At the same time, the available volumes in different projects differed, which could affect the combat qualities of the products.
Expected finale
Using a set of basic ideas and combining them in different ways, A. Lippisch proposed eight basic architectures for a rocket-assisted projectile. All of them had certain features, advantages and disadvantages. Continuing research work, the LFW institute could develop the proposed ideas and build on their basis real ammunition for artillery.
It is known that when working on new ARS, scientists have carried out some research and testing. In particular, based on the results of such work, the optimal fuel options were determined. Whether ready-made shells were built and whether they were tested is unknown. Well-known factors interfered with such work.
Perhaps the continuation of work on the ARS could lead to real results and even ensure the rearmament of the German army. However, the report on the new project came too late. The command was reported about it only at the very end of 1944, when the outcome of the war for Germany was obvious.
For the remaining months before the surrender, the LFW Institute was unable to complete a single promising project in the field of aviation or artillery. Many samples of weapons and equipment that previously seemed promising remained on paper. After the war and moving to the USA, A. M. Lippisch focused on aviation technology and did not return to the artillery theme.
Unnecessary project
The overly daring projects of A. Lippisch and V. Trommsdorff did not in any way affect the combat capability of the Wehrmacht. Even their most successful developments did not advance beyond the field tests, and in practice did not come to the introduction of ARS with a ramjet engine. Moreover, these ideas were never developed further. Apparently, the experts of the winning countries got acquainted with the work of the LFW - and dismissed them as useless.
In the post-war period, all leading countries have their own active-rocket projectiles in service. These were products with solid propellant rocket engines. Also, simpler shells with a bottom gas generator have gained a certain distribution. The ramjet engines were never able to gain a foothold in the field of artillery shells.
However, the concept has not been forgotten. Last year, the Norwegian industry presented a draft 155-mm ARS with a solid-propellant ramjet. In the near future, it should be tested, after which the issue of launching production and procurement can be resolved. It is not known whether this projectile will be able to reach exploitation and not repeat the fate of A. Lippisch's developments.
