The sunset could be farther off than thought for the F/A-18E/F Super Hornet, the mainstay of the U.S. Navy’s carrier-based fighter fleet. With initial operational capability of the F-35C Joint Strike Fighter that will eventually replace the F/A-18 now planned in early 2019, Boeing and partner Northrop Grumman are proposing an “Advanced Super Hornet” upgrade designed to operate until 2030 and beyond.
This summer, Boeing conducted test flights of an F/A-18F Super Hornet demonstrator with conformal fuel tanks (CFTs) built by Northrop Grumman, a centerline enclosed weapons pod (EWP) and “signature enhancements” for increased stealth. The external modifications, matched with an upgraded F414-GE-400 engine, an upgraded Raytheon APG-79 active electronically scanned array (AESA) radar and other improvements, substantially increase the range and reduce the radar signature of the Navy’s Block II Super Hornet.
The upgrade package readies the F/A-18 for the “anti-access, area denial” threat environment of the future, Boeing contends, and offers the Navy an affordable, low-risk solution that contrasts with the expensive F-35. It would also make the EA-18G Growler electronic warfare variant of the fighter more effective.
Boeing (Stand 1606) and Northrop Grumman (Stand 2051) self-funded the demonstration using a Super Hornet leased from the Navy. The modified demonstrator made its first flight on August 5 in St. Louis and conducted a series of test flights at both the Boeing Defense facility next to Lambert St. Louis International Airport and the Patuxent River, Maryland, Naval Air Station. In late August, Boeing test pilot John Tougas and weapon systems officer John Simmons flew the aircraft at St. Louis for reporters and visiting delegations from Brazil and Denmark. The F/A-18E/F figures in fighter competitions in both countries.
The aim of the test flights was to validate the aerodynamics and radar signature performance of the non-operating or “dry” CFTs designed by Northrop Grumman, which already produces the F/A-18’s aft/center fuselage section and vertical tails at its El Segundo, California facility. The prototype CFTs weighed 1,500 pounds; production fuel tanks would weigh 870 pounds and carry 3,500 gallons of fuel. The centerline EWP built by Boeing, also a non-operating prototype, weighed 2,050 pounds. The production pod would weigh 900 pounds and carry a mix of weapons, including AIM-120 air-to-air missiles, laser-guided munitions and bombs, weighing up to 2,500 pounds.
Greater Mission Radius
Tests have shown the CFTs installed on the upper fuselage increase the Super Hornet’s mission radius by up to 130 nm, for a total radius exceeding 700 nm. The CFTs add no drag to the aircraft at subsonic speed; at transonic or supersonic speeds they produce less drag than a centerline fuel tank, Boeing said. Enhancements to the aircraft’s radar cross section, including the EWP, produced a 50-percent improvement in its frontal low-observable (LO) signature. “We have worked very hard to make sure that the CFTs were not a negative contributor to the [radar] signature,” said Paul Summers, Boeing Super Hornet and Growler director.
CFTs on the Growler would provide equivalent mission performance in terms of range and performance, but with 3,000 pounds less fuel, compared to an EA-18G fitted with two 480-gallon external fuel tanks, three jamming pods and two AGM-88 HARM anti-radiation missiles. Summers said the removal of the external fuel tanks would enable the ALQ-99 tactical jamming pods and their planned replacement system in 2020, the Next Generation Jammer, to have an unobstructed field of regard for jamming. “Historically, the fuel tanks tend to block some of the radiation coming off of the airplane,” he said.
Next year, Boeing plans to incorporate an internally mounted Lockheed Martin infrared search-and-track system under a Super Hornet nose as part of a “multi-ship/multi-spectral” demonstration of data sharing with the Navy, involving an E-2D Hawkeye airborne early-warning aircraft. Participating aircraft will share data from multiple sensors using Rockwell Collins’ tactical targeting network technology (TTNT) waveform, which supports high data-rate, long-range communications.
The Advanced Super Hornet package includes a “next-generation cockpit” featuring an 11- by 19-inch main touchscreen display developed by Elbit Systems that replaces other, smaller multifunction displays. The large area display also figures in Boeing’s F-15SE Silent Eagle export fighter.
Some or all of the upgrades could be retrofitted or included as forward fit options on the Super Hornet. Mike Gibbons, Boeing’s F/A-18 and EA-18G program vice president, said the cost of developing the entire set, including an upgraded GE Aviation F414-GE-400 engine, would be “less than a billion dollars” and could be done by 2020. He estimated that the package would add 10 percent to $50 million flyaway cost of a Super Hornet.
Separate to the Boeing effort with Northrop Grumman, GE Aviation and the Navy have spent $100 million over 10 years developing elements of an F414-GE-400 “enhanced engine” upgrade, involving changes to the combustor and high-pressure turbine. Tests indicate the enhanced engine would provide 3 percent lower fuel consumption, increased time on wing and optionally 20 percent more thrust.
“You could run [the engine] at today’s thrust level–22,000 pounds–with new materials and get a significant increase in time-on-wing because it’s more durable,” said Daniel Meador, of GE Aviation military systems operations. “If the customer needed an improvement in capability, they could do that, the hardware is already there. They could change the Fadec [full-authority digital engine control] software and get a 20-percent increase in thrust. You would see today’s excellent durability at a higher temperature.”
Boeing and GE Aviation contend that the enhanced engine would save the Navy $5 billion in scheduled and unscheduled maintenance visits and reduced fuel consumption over the life of the Super Hornet, which in itself would pay for the entire set of proposed upgrades. Meador said GE is conducting component testing of the enhanced engine, and is prepared for a detailed design and qualification effort. The company hopes the Navy will include the enhanced engine as a program of record in its 2016 program objective memorandum.
GE Aviation currently has a performance-based logistics contract to sustain the F414-GE-400 engine at NAS Jacksonville, Florida. “We would propose that a -400 [engine] would come in when it needs to come in. You would have a separate line that would replace the parts and the modules there and it would come out as an enhanced engine,” said Meador. The company would be able to retrofit about 300 engines per year, its current service rate, he said.