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Monday, January 26, 2009

navy Turbocharges it Missiles

HsadThe Navy is developing a new type of rocket engine to make missiles faster and more deadly.

A while back, we reported on the "killer zombie" QF-4 Phantom. It's an obsolete jet, resurrected as an unmanned drone for test-firing missiles. Now we know a bit more about the super-fast weapon fired by the killer zombie.

The Higher Speed Antiradiation Demonstrator (HSAD) is another project to upgrade the AGM-88 HARM missile, used to knock out enemy air defense radar. HARM is a modular weapon, with separate warhead, seeker, controls and propulsion. That means different elements can be upgraded separately. HSAD replaces the existing rocket motor with a "turbocharged" version.

The program has been quietly progressing since 2002, when the Navy decided to develop a missile based on new propulsion technology. Work is being carried out at the Naval Air Warfare Center Weapons Division at China Lake, CA.

The goal is to test a new propulsion system that can provide "additional range and average velocity to a next generation Anti-Radiation Missile," Jerry Kong, the Navy's HSAD program manager, tells Danger Room. To make it happen, his team is building a hybrid propulsion system called an "Integral Rocket Ramjet" -- also known as a "ram-rocket."

Ordinarily, ramjets use high-speed airflow as natural compressors for jet engines. It's a turbocharger, in effect. Kong's crew is putting together a rocket that uses its combustion chamber as a ramjet, producing a significantly increased thrust. In theory, it's simple enough. But getting the engineering right has taken a while. This really is rocket science, after all.

The IRR has the high speed and ability to start from zero velocity of a rocket with the added endurance of an air-breathing ramjet. On paper, a ram-rocket should be able to generate about twice the total thrust of a rocket. "Higher speed and range for an anti-radiation missile is important as it increases the survivability of strike aircraft," says Kong.

If a surface-to-air radar locks on to your aircraft, then your survival may depend on knocking the radar out before its missiles can hit you. Some Russian-built SAMs are huge and have a speed of mach 5 or more , so being the "fastest gun" can be a matter of life or death.

The Navy is vague about details of just how good HSAD is, suggesting only a performance of mach 3+ with a range of 100 miles. But HSAD's contractor indicates that HSAD will have "twice the range of the current HARM at two to three times the average velocity as HARM." This suggests more like mach 4+ and 150+ miles. (They quote average speed because HARM spends some its flight gliding after the rocket burns out; HSAD will have a longer burn time.)

However, HSAD itself is not a finished product or even a prototype. The result of the HSAD program is a technical data package which should prove that the ram-rocket works. This will then be taken up and developed into end products, which may be some years off.

The Air Force have also taken an interest in HSAD, and the technology might also be incorporated into all sorts of other missiles to give them greatly enhanced speed and range.

"This capability would be useful to many future weapon systems and is being studied for applications in air-to-air, air-to-ground and ground-to-ground weapon systems," says Kong.

In principle, the integrated rocket ramjet could improve the performance of all sorts of missiles. And as HSAD shows, it's possible to add it on to existing systems. Increased range is generally useful, and increased speed improves the chances of an anti-aircraft weapon. History suggests that in the longer run, it might spread even further: early satellite launches (including Sputnik and the U.S. Explorer 1) were carried out using modified military ballistic missiles. Ram-rockets may start out on radar-killing missiles, but ultimately the technology is likely to find to way into all sorts of places.

[Photo: Ares]

By David Hambling EmailJanuary 26, 2009 | 9:39:00 AMCategories: Ammo and Munitions, Missiles