page_title: Lockheed F-104 Starfighter
section_title: Airframe
hierarchical_section_title: Lockheed F-104 Starfighter / Design / Airframe
caption_attribution_description: A formation of two U.S. Air Force Lockheed F-104A-15-LO Starfighters (s/n 56-0769 and 56-0781) in flight.
context_page_description: The Lockheed F-104 Starfighter is a single-engine, supersonic interceptor aircraft which was extensively deployed as a fighter-bomber during the Cold War. Created as a day fighter by Lockheed as one of the Century Series of fighter aircraft for the United States Air Force, it was developed into an all-weather multirole aircraft in the early 1960s and produced by several other nations, seeing widespread service outside the United States.
  After a series of interviews with Korean War fighter pilots in 1951, lead designer Kelly Johnson opted to reverse the trend of ever-larger and more complex fighters and produce a simple, lightweight aircraft with maximum altitude and climb performance. On 4 March 1954, the Lockheed XF-104 took to the skies for the first time, and on 26 February 1958 the production fighter was activated by the USAF. Only a few months later it was pressed into action during the Second Taiwan Strait Crisis, when it was deployed as a deterrent to Chinese MiG-15s and MiG-17s.
context_section_description: The Starfighter's airframe was all-metal, primarily duralumin with some stainless steel and titanium. The fuselage was approximately two and a half times longer than the airplane's wingspan. The wings themselves were centered on the horizontal reference plane, or along the longitudinal centerline of the fuselage, and were located substantially farther back on the fuselage than most contemporary designs. The aft fuselage was somewhat elevated from the horizontal reference plane, resulting a somewhat "lifted" tail, and the nose was "drooped"; this caused the aircraft to assume a slight "nose-up" attitude in level flight, which allowed the plane to fly at an angle of attack experiencing the minimum amount of drag through the air. As a result, the pitot tube, air inlet scoops, and engine thrust line were all canted slightly with respect to the longitudinal centerline of the fuselage.
  The F-104 featured a radical wing design. Most jet fighters of the period used a swept-wing or delta-wing, which provided a reasonable balance between aerodynamic performance, lift, and internal space for fuel and equipment. The Lockheed tests, however, determined that the most efficient shape for high-speed supersonic flight was a very small and thin, straight, mid-mounted, trapezoidal wing. Much of the data on the wing shape was derived from testing done with the experimental unmanned Lockheed X-7, which used a similar-shaped wing. The leading edge of the wing was swept back at 26 degrees, with the trailing edge swept forward by a slightly smaller amount.
  The new wing design was extremely thin, with a thickness-to-chord ratio of only 3.36% and an aspect ratio of 2.45. The wing's leading edges were so thin (.016 in, 0.41 mm) that they presented a cut hazard to ground crews: protective guards had to be installed on the edges during ground operations maintenance. The thinness of the wings required fuel tanks and landing gear to be placed in the fuselage, and the hydraulic cylinders driving the ailerons were limited to 1-inch (25 mm) thickness in order to fit.
  The small, highly loaded wing resulted in an unacceptably high landing speed, even after adding both leading- and trailing-edge flaps. As a result, the aircraft designers developed a boundary layer control system, or BLCS, of high-pressure bleed air, which was blown over the trailing-edge flaps to lower landing speeds by more than 30 knots (56 km/h; 35 mph) and help make landing the airplane safer. Flapless landings, however, would be without the BLCS engaged, as flaps in the "land" position were required for its operation. Landing without the BLCS engaged was only done in emergencies and could be a harrowing experience, especially at night.
  The stabilator (fully moving horizontal stabilizer) was mounted high atop the fin to reduce inertia coupling. Because the vertical fin was only slightly shorter than the length of each wing and nearly as aerodynamically effective, it could act as a wing-on-rudder application, rolling the aircraft in the opposite direction of rudder input. To offset this effect, the wings were canted downward at a 10° negative-dihedral (anhedral) angle. This downward canting also had the effect of improving roll control during high-g maneuvers commonly used in air-to-air combat.
  The fuselage had a high fineness ratio, i.e. was slender, tapered towards the sharp nose, and had a small frontal area. The tightly packed fuselage contained the radar, cockpit, cannon, fuel, landing gear, and engine. The fuselage and wing combination provided low drag except at high angle of attack (alpha), at which point induced drag became very high. The F-104 had good acceleration, rate of climb, and top speed, but its sustained turn performance was poor. A "clean" (no external weapons or fuel tanks) F-104 could sustain a 7-g turn below 5,000 feet with full afterburner, but given the aircraft's prodigious fuel consumption at that altitude and relatively small fuel capacity, such a maneuver would dramatically reduce its time on station.
caption: Lockheed F-104A
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