Missiles travelling at high speeds in the supersonic range require very fast and very effective controlling methods to be able to reach the target with high precision. Additionally, high temperature loads are challenging not only the structure of the body but also the requirements of the onboard-systems e.g. seeker dome sensors and guiding systems. Therefore, missile technologies and design methods were developed or improved for 3.5 years at various institutes of the DLR. The work focused on the requirements defined by the needs of an efficient controlling method and thermal loads which are making high demands on single components. These components of interest were engine, seeker-dome, development of new materials, and the aerodynamic design of inlets and control elements.
In the frame of the project two possible methods for controlling missiles have been investigated in the Institute of Aerodynamics and Flow Technologies in the department of high speed configurations. One of the two methods is the control of missiles with grid fins. Here, the rear of the body is equipped with grid fins that can be stowed by folding them down against the missile body. The grid fins consist of a lamellae construction, which owe their simplicity some advantages: they are stable due to their structure, produce only very small hinge moments, and have a nearly constant centre of pressure. Above all this, they produce a four times higher lift in comparison to conventional control fins and are herewith much more effective. Within the project different grid fin configurations were tested in the Mach number range of 0.3 <= M <= 6 in the Transonic Wind Tunnel Facility (TWG) and the Ludwieg Tube (RWG) of the DLR-Göttingen. The focus of the investigation was the efficiency of the fins and the development of a tool for the design and optimisation of isolated grid fins („FastGRIDS“).
The second control method under investigation was the so-called Side Jet Control. Here, a jet is being issued under high pressure from a cartridge perpendicularly to the flow direction that can be used to control the body. During the project extensive studies have been conducted in the Ludwieg tube (RWG), in which the influence of different jet configurations on the efficiency of the side jet control was tested. The measurements were associated with numerical simulations with the DLR-TAU-code so that selected cases were simulated under the same conditions as in the wind tunnel and were used to validate the code.
Another focal point was the investigation of unsteady phenomena on missiles during manoeuvring flight. In manoeuvring flight a body is moving with transonic speeds and under high angles of attack and roll. This provides the body with large asymmetric aerodynamic loads due to vortices produced along the body and which are interacting with the body, fins or control surfaces. The aim of this project was the application and further development of technologies for the experimental investigation of unsteady procedures on a missile in manoeuvring flight. An according missile was manufactured and tested under free rolling conditions in wind tunnel studies in the Transonic Wind Tunnel Facility of the DLR Göttingen (TWG).