A prototype of an advanced F-18 Super Hornet has undergone extensive flight testing by Boeing and its partner, Northrop Grumman, to demonstrate its capabilities.

The testing, which involved 21 flights by the prototype, were funded by the companies and took place earlier this month at St. Louis and at Patuxent River, Md.

The aircraft features conformal tanks, a centerline pod containing weapons, and some signature improvements, which can also be retrofitted on existing Block II Super Hornets, Boeing said.

"We continually insert new capabilities into today's highly capable, already stealthy Super Hornet, and the Advanced Super Hornet is the next phase of this technology evolution," said Debbie Rub, Boeing Global Strike vice president and general manager. "Boeing and our industry partners are investing in next-generation capabilities so warfighters have what they need when they need it, and so the customer can acquire it in a cost-effective manner."

Boeing said improvements to the aircraft's radar signature, including the enclosed pod, resulted in a 50 percent reduction compared with the U.S. Navy's stealth requirement for the current Super Hornet variant.

The tests also showed the conformal fuel tanks increased the fighter's combat radius by up to 130 nautical miles. With the conformal fuel tanks, the Advanced Super Hornet has a combat radius of more than 700 nautical miles.

"We invested in conformal fuel tank research and development so we could offer our domestic and international customers the most capable and sophisticated F/A-18 possible," said John Murnane, F/A-18 program manager at Northrop Grumman Aerospace Systems, which produced the tanks. "Given the challenge of developing the CFT in a short period of time, the success of the first prototype flight is an incredible achievement for our team."

The tanks, which are added to the upper fuselage of the aircraft, hold as much as 3,500 pounds of additional fuel. Northrop said they feature a stealthy, low-drag design.

Northrop Grumman produces about 40 percent of the work content for F/A-18 and about 50 percent for the electronic warfare variant, the EA-18G. It manufactures the center and aft fuselage and vertical tails for both aircraft and the airborne electronic attack subsystem for the EA-18G.

The enclosed weapons pod on the prototype was designed and built by Boeing.

"The improvements will ensure that the Advanced Super Hornet outpaces enemy aircraft and defenses through 2030 and beyond, especially when that enemy tries to deny access to a specific area, such as skies over international waters near its assets," Boeing said.

In addition to Boeing and partner Northrop Grumman, GE Aviation and Raytheon are involved in the Advanced Super Hornet program. Boeing said both those companies are investing in more advanced technologies for the Advanced Super Hornet. Those technologies include internal Infrared Search and Track, an enhanced engine and a next-generation cockpit.