After years of courting from afar, Boeing seems to finally have caught the U.S. Navy's attention—and support—for a series of upgrades for the F/A-18E/F designed to improve its stealthiness and keep it relevant against threats well beyond 2030.

With 25 hr. of flight time on new, stealthy F/A-18 fuel tanks and more upgrade trials planned, the company has shed any pretense of targeting the Defense Department.

“This is no longer something we consider to be just an international play,” says Paul Summers, Boeing's F/A-18 and EA-18G director. The upgrades “fit the domestic market better right now,” adds Mark Gammon, program manager for Super Hornet and Growler advanced capabilities.

The upgrade project began under the nebulous F/A-18E/F “International Roadmap” moniker, a 2010 rollout of a menu of improvements for the twin-engine fighter. The company briefed the capabilities to foreign customers, showcased them at air shows abroad and simply kept the Navy in the loop—as a courtesy, officials say. Until now, Boeing executives have been quick to correct any suggestion that Super Hornet improvements were ultimately trained on its largest Super Hornet customer, the Pentagon. But the strategy of shopping them around the globe was clearly to whet the Navy's appetite.

The ultimate prize for Boeing would be to unseat the F-35C as the Navy's future fighter. The service's interest coincides with its cautious support of the F-35C project. While the Marine Corps plans to declare initial operational capability (IOC) by December 2015, and the Air Force a year later, the Navy is more measured with its intention for an IOC in 2019. Boeing officials stopped short of suggesting the Advanced Super Hornet—with its optional engine upgrade, frontal-aspect stealth improvements and situational awareness adds—could be an alternative to Lockheed Martin's F-35C. But the upgrades target a threat in 2030 and beyond, well into the sweet spot for which the F-35C is designed to operate. “We based our design on [a] good enough [approach],” aimed at value rather than incorporating higher levels of all-aspect stealth, says Mike Gibbons, vice president of the Super Hornet and Growler programs for Boeing.

Though the Navy is not yet funding the upgrades, it is onboard with the concept. The service is allowing Boeing to lease one of its new Super Hornets for demonstration flights and is requesting some specific design tweaks—like improved fuel load in stealthy fuel tanks. Officials on the Super Hornet industry team suggest funding for at least some of the upgrades, such as the engine enhancement, could come as early as the 2016 budget, which will be drafted next summer.

Lockheed Martin has yet to conduct ship trials with the carrier variant; the company was forced to redesign its tailhook, which bounced over the wire during taxi tests. So flight testing for some of the Advanced Super Hornet components, started Aug. 5 on the company dime, come as the Navy is still open to options.

The entire array of upgrades could be developed for less than $1 billion, says Gibbons. If the service were to buy new F/A-18E-Fs with the upgrades, the flyaway cost would be roughly $56 million, or 10% higher than the most recent flyaway price—$51 million—in the third multiyear buy as cited by the company (this includes the aircraft, both engines and electronic-warfare gear).

Modifying existing aircraft is an option, though the kit and installations would cost slightly more than the 10% cited for new-builds, Gibbons says. Plumbing and wiring would need to be installed to support the conformal fuel tanks (CFT) and external weapons pod. The Navy owns 491 of 563 Super Hornets planned and 90 of 135 Growlers, and Pentagon support could prompt more commitments from export customers.

Though not discussed by company officials, Boeing is likely to heavily incentivize the Navy's interest in new-build aircraft in an effort to impel the service to pursue the strategy used by the Royal Australian Air Force of delaying F-35 purchases in favor of ongoing F/A-18E/F gap-filler buys.

“We didn't chase this specific set of technologies because of the F-35,” Gibbons told reporters during an Advanced Super Hornet briefing. “Affordability is the key differentiator for us.”

Based on recently announced low-rate, initial production contracts 6 and 7, the F-35C cost is estimated at $137.7 million and $132.9 million, respectively (AW&ST Aug. 5/12, p. 30). Included in this tally are the price of the airframe, engines and retrofits expected to be added to the aircraft based on the findings of ongoing flight testing. Ultimately, the average F-35A is expected to cost $80-90 million, Air Force Lt. Gen. Christopher Bogdan said last year; the C is likely to be slightly higher due to unique equipment and a notably smaller anticipated buy.

Summers says the Navy can avoid about $5 billion of cost into the 2040s if it opts for the F414 engine upgrade alone, owing to its expected efficiencies; General Electric is in direct talks with the Navy on options. Meanwhile, the CFTs—about 24 ft. long by 4 ft. wide—have shown “very little drag” on the aircraft between Mach 0.6 and 0.84, says John Murnane, head of Northrop Grumman's CFT program. He says the performance is better than a clean aircraft in transonic or supersonic operations. Though the Growler electronic-attack aircraft will operate as a standoff asset, the Navy is considering adding CFTs onto the platform for improved range.

With more than $100 million of GE investments in various components of the upgraded engine over the past decade, the program is ready for an official start next year, says Dan Meador, manager of Navy and Marine Corps programs for GE. Company officials say the shrouded blisk fan hardware is finished and testing is set for fourth-quarter 2013. The high-pressure compressor and turbine have also been demonstrated. The company hopes to garner Navy funding to continue trials and move forward with qualification work. Meador suggests that the improvements can be added as the engines are rotated for depot maintenance; GE handles such work on about 300 engines annually.

The company expects a 50% reduction in scheduled and unscheduled shop visits, improved resistance to foreign object damage, 20% more thrust and 3% lower fuel consumption than the current F414.

The first upgrades to be flight tested are the aerodynamic qualities and radar-cross-section performance of the two conformal, top-mounted CFTs as well as a low-observable, centerline-mounted internal-carriage weapons pod. Boeing has leased a Navy Super Hornet fresh off the production line until the end of October for these trials. The demonstrator aircraft also includes about 100 lb. of radar-absorbing or scattering coatings at specific locations.

For flight-testing purposes, the prototype Advanced Super Hornet CFTs are nonfunctioning and weigh about 1,500 lb., simulating the production tank at a low-fuel state, says Summers. The objective tanks, being developed with funding from and to be built by Northrop Grumman, would weight 870 lb. and the two together would carry 3,500 lb. of fuel, 500 lb. more than the CFTs envisioned only a few years ago in the International Roadmap. The additional fuel was added at the request of the Navy, Summers says.

Likewise, the prototype external weapons pod being flown on the Super Hornet demonstrator is nonfunctioning. It weighs about 2,050 lb. The objective version, built by Boeing, would weigh 900 lb., and carry about 2,500 lb. of weapons in various loadout configurations.

The upgrades designed for low observability—including the CFTs, weapons pod and a redesigned radar blocker for the engine inlet—will deliver a 50% improvement over the current Super Hornet's frontal-aspect low observabilty, Gibbons says.

Both flew in a short flyby demonstration Aug. 27 at Boeing's fighter production facility in St. Louis; the event was attended by media as well as onlookers from Brazil and Denmark, both potential customers for the Super Hornet and its upgrade program.

The aircraft is now being prepared for four flight trials at NAS Patuxent River, Md. Two are slated to include operations with the CFTs only, and the remaining two are set to include at least one, but up to four, externally mounted Raytheon AGM-154 Joint Standoff Weapons (JSOW). The Navy selected the weapon with which to conduct these tests. The goal of these flights is to validate the signature work already performed at Boeing's near-field radar chamber and to run similar radar cross-section analyses of the aircraft loaded out with JSOW.

Boeing has begun conceptual work to determine if weapons pods could also be mounted on each wing of the Super Hornet to increase the internal carriage payload, Summers says.

Boeing's current Super Hornet backlog allows for work through 2016, so the pressure is on to obtain Navy backing to avoid having to underwrite the cost of keeping the production line open.

Tap on the icon in the digital edition of AW&ST for a video of the F/A-18E/F demonstrating new conformal fuel tanks and a weapons pod designed to optimize frontal aspect stealth qualities, or go to See Boeing's briefing on the Advanced Super Hornet's features at:

Super Hornet Upgrade Options
Improvement How It’s Done
50% Frontal Radar Cross-Section Reduction Conformal fuel tanks carrying a total of 3,500 lb. of fuel also produce 260-mi. range improvement while carrying medium load of external weapons Centerline weapon pod carrying up to 2,500 lb. of payload 100 lb. of radar-absorbing/scattering materials New radar-blocker design for engine inlet, including new radar-scattering material
F414 Engine Enhancement 10% higher airflow in same size engine 50% reduction in shop visits 3% lower fuel consumption at current thrust Optional 20% thrust increase Three-stage fan with all-blisk designHigh-pressure compressor stages reduced to 6 from 7Shrouded blisk in Stage 1 fanHigh-efficiency 3-D aerodynamic design tools used for both compressor and fan
Improved Situational Awareness 11 X 19-in. touchscreen cockpit displaysLow-profile, internally mounted infrared search-and-tracking sensor
Source: Boeing