FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1989
1989 - 1130.PDF
The Hughes/Raytheon AAAM contender (above and below) features integral rocket-ramjet propulsion conferring high velocity with long range. It uses both active and passive seekers for autonomy from launch aircraft The AAAM competitors are required to make their missiles compatible with Sparrow launchers, and the missiles are only 12ft long. This is how Hughes/Raytheon AAAMs would look on an F-14 proposed a more radical design which combines active radar and EO guidance for full "fire-and-forget" capability, and is powered by an integral rocket /ramjet rather than a solid-propellant rocket. This missile would be mounted on an aircraft in the normal manner, and a Hughes/Raytheon drawing shows eight on an F-14D—two under each wing, one on either side of the lower fuselage just below the inlets, and two in tandem on the centreline. Although this team has released less written information of its proposed weapon, it has issued a detailed drawing of the missile's internal arrangement, including the integral rocket/ramjet propulsion system. On the Hughes/Raytheon AAAM design, the inlet is mounted beneath the fuselage and just ahead of the low-set wings. Directly above is a large tank which houses the liquid fuel which is injected into the ramjet com bustion chamber. Air-breathing powerplants are more complex than solid rockets, but are more efficient as a result of using air rather than an oxygen-bearing compound in the propellant charge, to support combustion. Tit for tat One published report has suggested that, although the Hughes/Raytheon missile will have a lower acceleration than that of the rival GD / Westinghouse design, the air- breathing missile will be faster at ranges beyond about two-thirds of maximum. The GD/Westinghouse team claims that its rocket sustainer "expands the high-altitude envelope, where air-breathing missiles cannot operate". Given that the ramjet- powered Talos SAM used by the US Navy in the 1960s and early 1970s was credited with a ceiling of more than 85,000ft (26,000m), the question remains of just how high a ceiling this team has in mind. Another surprise in the Hughes/ Raytheon design is the use of a single pair of wings, rather than the cruciform configuration which is a feature of most other present-day designs. Like a manned aircraft, the missile will have to bank as it turns, a technique known in the missile industry as "twist and steer". First used in the early 1940s on the world's first air-to-air guided missiles—the Henschel Hs 298 and the Ruhrstahl X-4—the tech nique saw little post-war service other than on a few early air-to-air missiles built in the 1950s, such as the Sispre C-7 and Matra's R510 and 511, and on the Bristol/Ferranti Bloodhound SAM. The feature which has made "twist and steer" attractive for AAAM is its efficiency. Less energy is wasted by banked turns than by the skidding turns which result from the use of conventional cruciform surfaces. The guidance system is based around a reprogrammable computer. An imaging seeker (probably an IR device) is mounted at the tip of a radome covering the antenna of the active-radar seeker. A short section of the fuselage just forward of the fuel tank is occupied by the warhead. This is teamed with adaptive fuzing to ensure optimum triggering distance against targets of all types. Under present plans, full-scale develop ment of the winning design should begin in 1992. This is expected to run for four years, ending in 1996. The US Navy intends to buy 4,000 rounds to arm the F-14D, F/A-18, and the new A-12 Advanced Tactical Aircraft. The USAF has its own plan to develop a new air-to-air missile, an improved version of the AIM-120A AMRAAM, and currently claims to have no requirement for a missile in the class of AAAM. Congress is sceptical, however, and would like to see AAAM made a joint USAF/USN programme. 32 FLIGHT INTERNATIONAL, 22 April 1989
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
