Stewart Penney/BELFAST
Shorts Missile Systems (SMS) is closing on a solution to eliminate an adverse pressure wave when the Starstreak missile is fired from the Boeing AH-64 Apache attack helicopter.
Tests by the US Army have revealed problems with debris from the missile's packaging and a pressure wave created by the first stage rocket motor. Starstreak was designed as a high velocity surface-to-air missile, but its primary use on the AH-64 will be air-to-air.
SMS vice-president for sales and marketing Allister McQuoid says that the wingtip boxes which contain the air-to-air missiles will be modified "using a smart way" to diffuse the motor's plume.
McQuoid adds this "may or may not" be supplemented with a change to the chemistry of the first- stage motor to alter the initial impulse and resultant shockwave without affecting the flight profile. This modification has been tested by motor supplier Royal Ordnance, says McQuoid. The second-stage motor will be unaltered.
The problem of debris, which could be ingested by the engines, will be countered by using softer plastic to manufacture the sabots that cover Starstreak's three darts, while the cap on the front of the missile will be reshaped to fall away from the aircraft (Flight International, 9-15 June). Firings by the US Army have used standard rounds with a flat plate covering the end of the missile launch tube.
McQuoid says that, despite these changes, the missile will be 85-95% common with those in-service with British Army air defence units.
More US tests are due in September when the M3-plus 5km (3 miles)-range weapon will be evaluated against the Raytheon Stinger.
Questions remain over the need for an Apache air-to-air missile because of the limited threat, but McQuoid says the missile can also be used against ground targets, including armoured vehicles.
Apache modifications to integrate Starstreak include upgrading the Target Acquisition and Designation System (TADS) to fire a low-power laser at the rear of the missile and darts. The laser provides steering information to the missile and does not illuminate the target. A TADS upgrade would improve interception probability at the missile's maximum range.
Source: Flight International
