Hitting a new high

A European missile has achieved the world record hypersonic speed of mach 7, according to European defence firm EADS.

Known as the E1, the missile’s speed is the culmination of a 10-year research project to produce a weapon that could hit Scud-like rocket warheads in their launch-and-boost phase.

The ultimate goal of the project, a collaboration between the German and Swedish governments and EADS, is the development of a missile capable of achieving mach 13.

Such a missile would be fired by a UAV or manned aircraft towards the target, a tactical ballistic rocket about to be launched.

The missile flew 1 mach faster than its US rival, known as the Compact Kinetic Missile, which is being developed for an anti-tank role.

Peter Gleich, chief missile systems engineer in EADS defence and security systems, said that the new speed of mach 7 lent itself to other applications.

‘The missile would be used to shoot down incoming enemy missiles and hit radar stations. At Mach 7 it is good for air interception of sea skimmer missiles and air defence radar. If a radar tracks you in your aircraft, you could hit the installation before an enemy missile can be launched.’

The test missiles have been fired from northern Germany and recovered from the North Sea. EADS researchers are now investigating problems such as vibration, unstable aerodynamics, and the huge G-forces on the directional fins.

Gleich explained that flying at hypersonic speeds was like constantly hitting a wall of solid air, meaning the missile structure has to be very stiff and able to cope with extremely high temperatures.

As a result the E1 is made of carbon fibre, Kevlar and other artificial materials, which can cope well with the high temperatures of hypersonic flight. It contains only a small number of metal components.

With such high forces acting on the missile, changing direction can also be very difficult. Normally a missile uses fins to change direction but at hypersonic speeds shockwaves along the leading edge of any surface can cause instability.

So the EADS team has tested various designs for missile direction control. One of these involved using small rockets for what is called lateral thrust control. Another solution is fins that are not solid but instead have a tennis racket-like surface, called grid fins.

The advantage of these is that the location of the highest pressure point against the fin is closer to the actuator, which turns the fin. This means less force is needed to move the fin when it is encountering air resistance at high mach speeds, which can also induce G-forces.

As a result of these forces very good computer control is necessary to cope with the impact on the flightpath when making even the smallest directional change.

The next stage of the project is to secure more funding to continue the work. Gleich said that there were no plans to co-operate with the US, despite the common goal.