Graham Warwick/ST LOUIS

McDONNELL DOUGLAS (MDC) unveiled the first upgraded F-18E/F Super Hornet on 18 September, revealing design features incorporated to reduce the radar signature. Improved survivability is a design goal of the F-18 upgrade, along with increased range and payload and greater growth capacity.

Mike Sears, F-18 general manager, says that the reduction in radar cross-section is similar to that achieved in moving from the F-18A/B to the C/D, despite the E/F being 25% larger. Efforts to control signature have been focused on the nose and tail aspects, he says.

Low observability has been balanced with affordability, Sears says, adding: "This is not intended to be an invisible aircraft. It is not a silver bullet." The US Navy plans to buy 1,000 F-18E/Fs beginning in 1997, at an average flyaway unit cost of $36.4 million (in 1990 dollars).

The most obvious design change for stealth is the move to larger, rectangular, inlets for the more-powerful, 97kN (22,000lb)-thrust-class, General Electric F414 turbofans. The engine inlets are angled downwards and outwards to direct the radar-return "spikes" away from the nose-on aspect.

Less obvious is the use of fixed, airframe-mounted, radial vanes forward of the engine, to prevent radar energy reaching the rotating fan. Other stealth-design features of the F-18E/F include serrated edges on the main landing gear and engine-access doors, diamond-shaped, laser-drilled, metal screens covering all apertures, coatings and other surface treatments.

US Navy F-18 programme director Capt. Joe Dyer says, that analysis shows that the E/F is beating its low-observability target by a "good margin". He confirms that the aircraft's initial electronic-warfare suite will consist of the Hughes ALR-67(V)3 radar-warning receiver, Raytheon ALE-50 towed decoy and Tracor ALE-47 "smart" chaff/flare dispenser.

The first flight of development-aircraft E-1, a single-seat F-18E, is scheduled for early December and two aircraft will have been flown by the end of 1995. These will be used for early operational assessment, says Dyer. All seven flight-test aircraft, including two F-18F two-seaters, will have been flown by late 1996, MDC says. Three structural-test airframes will also be produced by early 1997.

The development programme is on schedule and on budget, and the aircraft is some 450kg under its specification weight, says Sears. The E/F has 33% fewer parts and the man-hours required for fabrication and assembly are about 12% under budget, he says.

MDC showed the F-18E/F's versatility when it displayed E-1 carrying six different under wing weapons: the AGM-88 high-speed anti-radar missile; AGM-84D Harpoon anti-ship missile; AGM-84H standoff land-attack missile (expanded response); GBU-29 joint direct-attack munition; AGM-154 joint standoff weapon; and AGM-65E Maverick air-to-surface missile.

Source: Flight International