The Lockheed F-94 Starfire was the United States Air Force's first operational jet-powered all-weather interceptor aircraft. It was a development by Lockheed of the twin-seat T-33 Shooting Star trainer aircraft. The F-94C Starfire was significantly modified from the early F-94 variants; in fact, it was initially designated F-97, but it was decided to treat it as just a new version of F-94. Initially, USAF interest was lukewarm, so Lockheed funded development themselves by converting two F-94B airframes to YF-94C types for evaluation. To improve performance, a totally new wing was fitted, much thinner than the previous one and a swept tail surface. The J33 engine was replaced by a more powerful Pratt & Whitney J48, a license-built version of the afterburning Rolls-Royce Tay which dramatically increased power, giving a dry thrust of 6,350 pounds-force (28.2 kN) and with afterburning approximately 8,750 pounds-force (38.9 kN) of thrust. The fire control system was upgraded to the new Hughes E-5 with AN/APG-40 radar in a much larger nose. The guns were removed, replaced with an all-rocket armament mounted in a ring around the nose radome. The rockets were loaded into flip-up panels on the sides of the nose, and fired by opening four panels just behind the radome. According to test pilot Tony LeVier, the F-94C was capable of supersonic flight.