Editing Lockheed F-104 Starfighter (section)

==Design==

===Airframe===
The Starfighter's airframe was all-metal, primarily [[duralumin]] with some stainless steel and titanium.<ref name="Dobrzyński2015p107">Dobrzyński 2015, p. 107.</ref> The fuselage was approximately two and a half times as long as the airplane's wingspan. The wings were centered on the horizontal reference plane, or along the longitudinal centerline of the [[fuselage]], and were located substantially farther aft on the fuselage than most contemporary designs. The aft fuselage was elevated from the horizontal reference plane, resulting a "lifted" tail, and the nose was "drooped". This caused the aircraft to fly nose up, helping to minimize [[drag (physics)|drag]]. As a result, the [[pitot tube]], air inlet scoops, and engine thrust line were all canted slightly from centerline of the fuselage.<ref name="Upton2003p21">Upton 2003, p. 21.</ref>

The F-104 featured a radical wing design. Most jet fighters of the period used a [[swept-wing]] or [[delta-wing]], which balanced aerodynamic performance, lift, and internal space for fuel and equipment. The Lockheed tests determined that the most efficient shape for high-speed [[supersonic]] flight was a very small and thin, straight, mid-mounted, [[trapezoidal wing]].<ref name="Bowman2000p28"/> Much of the data on the wing shape was derived from testing done with the experimental unmanned [[Lockheed X-7]], which used a wing of a similar shape.<ref name="Upton2003pp21–22">Upton 2003, pp. 21–22.</ref> The leading edge of the wing was swept back at 26 degrees, with the trailing edge swept forward by a slightly smaller amount.<ref name="Dobrzyński2015p107"/>

[[File:Lockheed F-104A-15-LO 060928-F-1234S-008.jpg|thumb|left|[[Lockheed Corporation|Lockheed]] F-104A|alt=Two F-104s flying in formation]]

The new wing design was extremely thin, with a thickness-to-[[chord (aircraft)|chord]] ratio of only 3.36% and an [[aspect ratio (wing)|aspect ratio]] of 2.45.<ref name="Pace1992p13">Pace 1992, p. 13.</ref> The wing's leading edges were so thin ({{convert|.016|in|mm|abbr=on|disp=semicolon}})<ref name="Pace1992p13"/> that they were a hazard to ground crews. Hence, protective guards were installed on them during maintenance.<ref name="pacificaviationmuseum">{{cite web|url=https://www.pearlharboraviationmuseum.org/pearl-harbor-blog/lockheed-f-104-starfighter/|title=Lockheed F-104 Starfighter: The Zipper.|access-date=10 May 2020|archive-date=7 January 2020|archive-url=https://web.archive.org/web/20200107092022/https://www.pearlharboraviationmuseum.org/pearl-harbor-blog/lockheed-f-104-starfighter/|url-status=dead}}</ref> The thinness of the wings required fuel tanks and [[landing gear]] to be placed in the fuselage, and the [[hydraulic cylinder]]s driving the ailerons were limited to {{convert|1|in|mm|adj=on}} thickness to fit.<ref name="Davies2014p8">Davies 2014, p. 8.</ref>

The small, highly loaded wing caused an unacceptably high landing speed, even after adding both leading- and trailing-edge [[flap (aircraft)|flaps]]. Thus, designers developed a boundary layer control system, or BLCS, of high-pressure [[bleed air]], which was [[blown flap|blown]] over the trailing-edge flaps to lower landing speeds by more than {{convert|30|kn}}, and help make landing safer.<ref name="Davies2014p11">Davies 2014, p. 11.</ref><ref name="Upton2003p22">Upton 2003, p. 22.</ref> Flapless landings 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.<ref name="Bowman2000p122">Bowman 2000, p. 122.</ref>

The [[stabilator]] (fully moving horizontal stabilizer) was mounted 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° [[Dihedral (aircraft)#Anhedral|negative-dihedral]] (anhedral) angle.<ref name="Bowman2000p28">Bowman 2000, p. 28.</ref> This downward canting also improved roll control during high-G maneuvers, common in air-to-air combat.<ref name="Pace1992p13"/>

The fuselage had a high [[fineness ratio]]. It 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-force|g]] turn below 5,000 feet with full afterburner. 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.<ref name="Bashow1986p24">Bashow 1986, p. 24.</ref>

===Engine===
[[File:F104Engine.JPG|thumb|alt=close-up of aircraft engine exhaust|Detail of F-104G's [[General Electric J79|GE J79]] turbojet exhaust (red coloring added by [[Technik Museum Sinsheim]], Germany)]]

The F-104 was designed to use the General Electric J79 turbojet engine,<ref name="Donald1997p578">Donald 1997, p. 578.</ref> fed by side-mounted intakes with fixed [[inlet cones]] optimized for performance at [[Mach (speed)|Mach]]&nbsp;1.7 (increased to Mach&nbsp;2 for later F-104s equipped with more powerful J79-GE-19 engines).<ref name="Davies2014p10">Davies 2014, p. 10.</ref> Unlike some supersonic aircraft, the F-104 did not have variable-geometry inlets; instead at high Mach numbers excess air was bypassed around the engine. This bypass air also helped cool the engine. Its thrust-to-drag ratio was excellent, allowing a maximum speed well in excess of Mach&nbsp;2. Available thrust was actually limited by the geometry of the inlet scoop and duct; the aircraft was capable of even higher Mach numbers if the aluminum skin of the aircraft were able to withstand the heating due to air friction. Furthermore, speeds above Mach&nbsp;2 quickly overheated the J79 engine beyond its thermal capabilities, which resulted in the F-104 being given a design airspeed limitation of Mach&nbsp;2.<ref name="Upton2003pp24–25">Upton 2003, pp. 24–25.</ref>

The engine consisted of a 17-stage compressor, an [[accessory drive]] section, an annular combustion chamber, a three-stage turbine, and an afterburner. The most powerful version of the J79, the J79-GE-19, was rated at {{convert|52.8|kN|abbr=on}} dry thrust and {{convert|79.6|kN|abbr=on}} with afterburner. Bleed air from the compressor's 17th stage was used for a number of purposes: the BLCS, cabin pressurization and air conditioning, hot-air jet rain removal, fuel transfer, canopy and windshield defogging and defrosting, pressure for the pilot's [[pressure suit|anti-G]] suit, pressurization and cooling of the nose-mounted radar equipment, and purging of gas from the M61 autocannon. The accessory drive ran two hydraulic pumps, two variable-frequency generators, the generator for the tachometer, and pumps for engine fuel and oil.<ref name="Dobrzyński2015pp108,112,114">Dobrzyński 2015, pp. 108, 112, 114.</ref><ref name="Upton2003p30">Upton 2003, p. 30.</ref>

===Armament===
The basic armament of the F-104 was the {{convert|20|mm|abbr=on}} M61 Vulcan autocannon. As the first aircraft to carry the weapon, testing of the Starfighter revealed issues with the initial version of the M61: the [[Gatling gun|Gatling]]-mechanism cannon suffered problems with its [[linked ammunition]], being prone to misfeed and presenting a [[foreign object damage]] (FOD) hazard as discarded links were occasionally sucked into the engine. A linkless ammunition feed system was developed for the upgraded M61A1 installed in the F-104C; the M61A1 has subsequently been used by a wide variety of American combat aircraft.<ref name ="f_106_delta_dart_m61">{{cite web|url=https://www.f-106deltadart.com/weapons_20mm_cannon.htm|title=M61A1 GAU 4 20-MM Vulcan Cannon|access-date=12 July 2017}}</ref>

[[File:F-104 Waffenschacht.jpg|thumb|alt=F-104G with open weapons bay showing M61 cannon|Open weapons bay of a [[German Air Force]] F-104G exposing the [[M61 Vulcan|M61 cannon]]|left]]
The cannon, mounted in the lower part of the port fuselage, was fed by a 725-round drum behind the pilot's seat. With its firing rate of 6,000 rounds per minute, the cannon would empty the drum after just over seven seconds of continuous fire.<ref name="militaryfactory">{{cite web|url=http://www.militaryfactory.com/aircraft/detail.asp?aircraft_id=113|title=Lockheed F-104 Starfighter Single-Seat High-Speed Fighter / Interceptor Aircraft|access-date=13 July 2017|date=18 June 2017}}</ref> The cannon was omitted in all the two-seat models and some single-seat versions including reconnaissance aircraft, with the gun bay and ammunition drum typically replaced by additional fuel tanks.<ref name="FrickerJackson1996p47">Fricker and Jackson 1996, p. 47.</ref>

Two AIM-9 Sidewinder air-to-air missiles could be carried on the wingtip stations, which could also be used for fuel tanks. The F-104C and later models added a centerline pylon and two underwing pylons for bombs, rocket pods, or fuel tanks; the centerline pylon could carry a [[nuclear weapon]].<ref name="militaryfactory"/> A "catamaran" launcher for two additional Sidewinders could be fitted under the forward fuselage, although the installation had minimal ground clearance and so rendered the seeker heads of the missiles vulnerable to ground debris. The two F-104S variants added a pair of fuselage pylons beneath the intakes for conventional bomb carriage and an additional pylon under each wing, for a total of nine.<ref name="the_aviationist">{{cite web|url=https://theaviationist.com/2009/04/21/f-104-versions-explained/|title=Italian F-104 versions explained|date=21 April 2009|access-date=13 July 2017}}</ref>

Early Starfighters were also capable of carrying and launching a single [[MB-1]] (AIR-2A Genie) rocket-powered nuclear missile using an extending trapeze launcher. This configuration was tested on a single aircraft but was not adopted for service use; however, NASA later used it for launching test rockets.<ref name="Davies2014p15">Davies 2014, p. 15.</ref>

===Avionics===

[[File:Radar dish of a F-104 Starfighter.JPG|thumb|alt=Museum display of an exposed F-104 radar dish|NASARR [[radar]] on F-104]]
The initial USAF Starfighters had a basic RCA AN/ASG-14T1 ranging radar, [[tactical air navigation system]] (TACAN), and an AN/ARC-34 UHF radio. The AN/ASG-14 fire control system used a {{convert|24|in|adj=on}} pencil-beam radar antenna with two independent sights: one optical and one infrared. Early versions of the radar had a range of approximately {{convert|20|mi}} in search mode, with later models reaching up to {{convert|40|mi}}; the scan pattern was spiral, covering a 90-degree cone. Search mode was usable only above {{convert|3000|ft}} due to ground return effects below that altitude. Track mode was usable within {{convert|10|mi}} of the target, which narrowed the scan to 20 degrees and initiated a strobe sweep between {{convert|300|and|3000|yd}} in auto-acquisition mode. The radar also had a third, receive-only mode useful for locking onto sources of interference from [[electronic countermeasures]] (ECM).<ref name="Davies2014p13">Davies 2014, p. 13.</ref>

In the late 1960s, Lockheed developed a more advanced version of the Starfighter, the F-104S, for use by the Italian Air Force. Similarly to the F-104G, Lockheed produced two main variants of the F-104S: an all-weather interceptor (''caccia intercettore'', CI) and a strike aircraft (''caccia bombardiere'', CB). The CI variant received a FIAR/NASARR F15G radar with AIM-7 Sparrow guidance capability; however, the new missile-guidance [[avionics]] came at the expense of the M61A1 Vulcan cannon, which was removed to make room. The CB variant was equipped with a FIAR/NASARR R21G-H radar and a radar altimeter for low-level strike missions, retaining the cannon as its only air-to-air weapon.<ref name="Dobrzyński2015p51">Dobrzyński 2015, p. 51.</ref>

As part of the ''Aggiornamento Sistema d'Arma'' (ASA), or "Weapons System Upgrade" in the mid-1980s, both variants were given an ALQ-70/72 ECM and a FIAR/NASARR R-21G/M1 radar with [[frequency hopping]] and [[look-down/shoot-down]] capability. The new radar and guidance systems enabled the aircraft to carry the new AIM-9L Sidewinder infrared-guided missile (replacing the older AIM-9B) as well as the AIM-7 Sparrow and the [[Selenia Aspide]] radar-guided missiles.<ref name="Dobrzyński2015p52">Dobrzyński 2015, p. 52.</ref>

===Ejection seat===
[[File:Martin-Baker Mk.7 Ejection seat - F-104 photo 2.jpg|thumb|upright=0.6|alt=Martin-Baker Mk.7 ejection seat removed from an F-104G|A [[Martin-Baker Mk.7]] ejection seat from an F-104G]]
Early Starfighters used a downward-firing [[ejection seat]] (the [[Stanley Aviation|Stanley]] C-1), out of concern over the ability of an upward-firing seat to clear the "T-tail" [[empennage]]. This presented obvious problems in low-altitude escapes, and 21 USAF pilots, including test pilot Captain [[Iven Carl Kincheloe Jr.]], failed to escape from their stricken aircraft in low-level emergencies because of it. The downward-firing seat was replaced by the Lockheed C-2 upward-firing seat, which was capable of clearing the tail, but still had a minimum speed limitation of {{convert|90|kn|mph km/h|abbr=on|0}}.<ref name="Upton2003p35">Upton 2003, p. 35.</ref> Many export Starfighters were later retrofitted with [[Martin-Baker Mk.7]] "zero-zero" (zero altitude and zero airspeed) ejection seats.<ref>[http://www.ejectionsite.com/frame_sg.htm "Ejection seats of the F-104."] ''ejectionsite.com.'' Retrieved: 6 February 2008</ref>

===Production assembly===
The Starfighter was designed for production rates of up to 20 airplanes per day from a single assembly line. The entire aircraft was designed for modular assembly and disassembly. The two principal fuselage sections were split along the vertical centerline and completely assembled in two separate halves. All equipment, including wiring and plumbing, was installed inside the two halves before being joined. The wings were then attached with ten bolts plus a [[Aircraft fairing|fairing]].<ref name="Upton2003pp16-19">Upton 2003, pp. 16–19.</ref>