Lockheed XF-104
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The Lockheed XF-104 Starfighter was a single-engine, high-performance,
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interceptor Interceptor may refer to: Vehicles * Interceptor aircraft (or simply "interceptor"), a type of point defense fighter aircraft designed specifically to intercept and destroy enemy aircraft * Ford Crown Victoria Police Interceptor, a police car * ...
prototype A prototype is an early sample, model, or release of a product built to test a concept or process. It is a term used in a variety of contexts, including semantics, design, electronics, and Software prototyping, software programming. A prototyp ...
for a
United States Air Force The United States Air Force (USAF) is the air service branch of the United States Armed Forces, and is one of the eight uniformed services of the United States. Originally created on 1 August 1907, as a part of the United States Army Signal ...
(USAF) series of lightweight and simple fighters. Only two aircraft were built; one aircraft was used primarily for
aerodynamic Aerodynamics, from grc, ἀήρ ''aero'' (air) + grc, δυναμική (dynamics), is the study of the motion of air, particularly when affected by a solid object, such as an airplane wing. It involves topics covered in the field of fluid dyn ...
research and the other served as an armament testbed, both aircraft being destroyed in accidents during testing.Bowman 2000, p. 33. The XF-104s were forerunners of over 2,500 production
Lockheed F-104 Starfighter The Lockheed F-104 Starfighter is an American single-engine, supersonic air superiority fighter 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 fi ...
s. During the Korean War, USAF fighter pilots were outclassed by MiG-equipped Soviet pilots. Lockheed engineers, led by Kelly Johnson, designed and submitted a novel design to the Air Force, notable for its sleekness, particularly its thin wings and missile-shaped fuselage, as well as a novel pilot ejection system. Flight testing of the XF-104s began with the first flight in March 1954, encountering several problems, some of which were resolved; however, performance of the XF-104 proved better than estimates and despite both prototypes being lost through accidents, the USAF ordered 17 service-test/pre-production YF-104As. Production Starfighters proved popular, both with the USAF and internationally, serving with a number of countries, including
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,
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, and Japan.


Development


Original requirement

Clarence L. "Kelly" Johnson, chief engineer at Lockheed's
Skunk Works Skunk Works is an official pseudonym for Lockheed Martin's Advanced Development Programs (ADP), formerly called Lockheed Advanced Development Projects. It is responsible for a number of aircraft designs, beginning with the Lockheed P-38 Lightn ...
, visited
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in December 1951 and talked to fighter pilots about what sort of aircraft they wanted. At the time, U.S. Air Force pilots were confronting the MiG-15 "Fagot" in their
North American F-86 Sabre The North American F-86 Sabre, sometimes called the Sabrejet, is a transonic jet fighter aircraft. Produced by North American Aviation, the Sabre is best known as the United States' first swept-wing fighter that could counter the swept-wing So ...
s, and many of the pilots felt that the MiGs were superior to the larger and more complex American design. The pilots requested a small and simple aircraft with excellent performance.Bowman 2000, p. 26. One pilot in particular, Colonel
Gabby Gabreski Francis Stanley "Gabby" Gabreski (born Franciszek Stanisław Gabryszewski; January 28, 1919 – January 31, 2002) was a Polish-American career pilot in the United States Air Force who retired as a colonel after 26 years of military service. He wa ...
was quoted as saying; "I'd rather sight with a piece of chewing gum stuck on the windscreen" and told Johnson that radar "was a waste of time".Bowman 2000, p. 26. On his return to the U.S., Johnson immediately started the design of just such an aircraft realising that an official requirement would soon be published. In March 1952, his team was assembled, and they sketched several different aircraft proposals, ranging from small designs at 8,000 lb (3.6 t), to fairly large ones at 50,000 lb (23 t). The L-246 as the design became known remained essentially identical to the "Model L-083 Starfighter" as eventually delivered.Bowman 2000, p. 32.


Tender of performance

The design was presented to the Air Force in November 1952, who were interested enough to create a new proposal, inviting several companies to participate. Three additional designs were received: the
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AP-55, an improved version of its prototype
XF-91 Thunderceptor The Republic XF-91 Thunderceptor (originally designated XP-91) is a mixed-propulsion prototype interceptor aircraft, developed by Republic Aviation. The aircraft would use a jet engine for most flight, and a cluster of four small rocket engines ...
; the
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NA-212, which would eventually evolve into the
F-107 The North American F-107 is North American Aviation's entry in a United States Air Force tactical fighter-bomber design competition of the 1950s. The F-107 was based on the F-100 Super Sabre, but included many innovations and radical design ...
; and the Northrop N-102 Fang, a new
General Electric J79 The General Electric J79 is an axial-flow turbojet engine built for use in a variety of fighter and bomber aircraft and a supersonic cruise missile. The J79 was produced by General Electric Aircraft Engines in the United States, and under lice ...
-powered design.


Selected design

Although all were interesting, Lockheed had an insurmountable lead and was granted a development contract in March 1953.Bowman 2000, p. 32. Test data from the earlier
Lockheed X-7 The Lockheed X-7 (dubbed the "Flying Stove Pipe") was an American unmanned test bed of the 1950s for ramjet engines and missile guidance technology. It was the basis for the later Lockheed AQM-60 Kingfisher, a system used to test American air def ...
unmanned ramjet/rocket program proved invaluable for aerodynamic research since the XF-104 would share the general design of the X-7's wing and tail.Upton 2003, p. 13. Experience gained from the
Douglas X-3 Stiletto The Douglas X-3 Stiletto was a 1950s United States experimental jet aircraft with a slender fuselage and a long tapered nose, manufactured by the Douglas Aircraft Company. Its primary mission was to investigate the design features of an aircraf ...
was also used in the design phase of the XF-104.Bowman 2000, p. 27. Over 400 surplus instrumented artillery rockets were launched to test various airfoils and tail designs; from which the camera film and telemetry were recovered by parachute.Upton 2003, p. 14.


Prototypes

The wooden
mock-up In manufacturing and design, a mockup, or mock-up, is a scale model, scale or physical model, full-size model of a design or device, used for teaching, demonstration, design evaluation, promotion, and other purposes. A mockup may be a ''protot ...
was ready for inspection at the end of April, and work started on two prototypes late in May. The J79 engine was not yet ready, so both prototypes were instead designed to use the
Wright J65 The Wright J65 was an axial-flow turbojet engine produced by Curtiss-Wright under license from Armstrong Siddeley. A development of the Sapphire, the J65 powered a number of US designs. Design and development Curtiss-Wright purchased a license f ...
, a licensed built version of the
Armstrong Siddeley Sapphire The Armstrong Siddeley Sapphire is a British turbojet engine that was produced by Armstrong Siddeley in the 1950s. It was the ultimate development of work that had started as the Metrovick F.2 in 1940, evolving into an advanced axial flow de ...
. Construction of the first prototype XF-104 ( US serial number ''53-7786'',
Buzz number Buzz number is a term applied to the large letter and number combination applied to United States Air Force military aircraft in the years immediately after World War II, through the early 1960s. This moniker evolved from aircrew speculation that ...
FG-786) began in summer 1953 at Lockheed's
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factory. This aircraft was powered by a non-
afterburning An afterburner (or reheat in British English) is an additional combustion component used on some jet engines, mostly those on military supersonic aircraft. Its purpose is to increase thrust, usually for supersonic flight, takeoff, and combat ...
Buick Buick () is a division of the American automobile manufacturer General Motors (GM). Started by automotive pioneer David Dunbar Buick in 1899, it was among the first American marques of automobiles, and was the company that established General ...
-built Wright J65-B-3 turbojet. The first prototype was completed by early 1954, and started flying in March. The total time from award of the contract to first flight was only one year, a very short time even then, and unheard of today, when 10–15 years is more typical.Upton 2003, p. 13. Construction of the second prototype (s/n ''53-7787'') proceeded at a slower pace.


F-104 production

Official approval of the XF-104 design led to a contract for 17 YF-104A service test aircraft and a production run of over 2,500 aircraft built both in the United States and under license worldwide. Visible changes from the XF-104 to production versions of the Starfighter include a longer fuselage (to accommodate the
J79 The General Electric J79 is an axial-flow turbojet engine built for use in a variety of fighter and bomber aircraft and a supersonic cruise missile. The J79 was produced by General Electric Aircraft Engines in the United States, and under lice ...
engine and extra internal fuel) and a forward-retracting nose landing gear (except two-seat versions) to increase clearance for the downward-ejecting seat. A ventral fin for increased stability was added during the YF-104A test program. Inlet shock cones and a fuselage spine fairing between the canopy and fin that housed fuel piping were further added features.Bowman 2000, p. 32.Upton 2003, p. 38. Production aircraft would also feature a redesigned fin structure using
stainless steel Stainless steel is an alloy of iron that is resistant to rusting and corrosion. It contains at least 11% chromium and may contain elements such as carbon, other nonmetals and metals to obtain other desired properties. Stainless steel's corros ...
spars The United States Coast Guard (USCG) Women's Reserve, also known as the SPARS (SPARS was the acronym for "Semper Paratus—Always Ready"), was the women's branch of the United States Coast Guard Reserve. It was established by the United States ...
to eliminate the flutter problem.Upton 2003, p. 45. Since the internal fuel capacity was low limiting the useful range of the aircraft, extra capacity was provided on later versions by lengthening the forward fuselage.


Design

In order to achieve the desired performance, Lockheed chose a minimalist approach: a design that would achieve high performance by wrapping the lightest, most
aerodynamically Aerodynamics, from grc, ἀήρ ''aero'' (air) + grc, δυναμική (dynamics), is the study of the motion of air, particularly when affected by a solid object, such as an airplane wing. It involves topics covered in the field of fluid dyn ...
efficient
airframe The mechanical structure of an aircraft is known as the airframe. This structure is typically considered to include the fuselage, undercarriage, empennage and wings, and excludes the propulsion system. Airframe design is a field of aerospa ...
possible around a single powerful engine. The emphasis was on minimizing drag and
mass Mass is an intrinsic property of a body. It was traditionally believed to be related to the quantity of matter in a physical body, until the discovery of the atom and particle physics. It was found that different atoms and different elementar ...
.Bowman 2000, p. 29.


Wing design

The XF-104 had a radical wing design. Most supersonic jets use a swept or
delta Delta commonly refers to: * Delta (letter) (Δ or δ), a letter of the Greek alphabet * River delta, at a river mouth * D ( NATO phonetic alphabet: "Delta") * Delta Air Lines, US * Delta variant of SARS-CoV-2 that causes COVID-19 Delta may also ...
wing. This allows a reasonable balance between aerodynamic performance,
lift Lift or LIFT may refer to: Physical devices * Elevator, or lift, a device used for raising and lowering people or goods ** Paternoster lift, a type of lift using a continuous chain of cars which do not stop ** Patient lift, or Hoyer lift, mobile ...
, and internal space for fuel and equipment. However the most efficient shape for high-speed,
supersonic Supersonic speed is the speed of an object that exceeds the speed of sound ( Mach 1). For objects traveling in dry air of a temperature of 20 °C (68 °F) at sea level, this speed is approximately . Speeds greater than five times ...
flight had been found to be a small, straight, mid-mounted,
trapezoid A quadrilateral with at least one pair of parallel sides is called a trapezoid () in American and Canadian English. In British and other forms of English, it is called a trapezium (). A trapezoid is necessarily a Convex polygon, convex quadri ...
al wing of low aspect ratio and high
wing loading In aerodynamics, wing loading is the total mass of an aircraft or flying animal divided by the area of its wing. The stalling speed of an aircraft in straight, level flight is partly determined by its wing loading. An aircraft or animal with a ...
. The wing was extremely thin, with a thickness-to- chord ratio of only 3.4%. The
leading edge The leading edge of an airfoil surface such as a wing is its foremost edge and is therefore the part which first meets the oncoming air.Crane, Dale: ''Dictionary of Aeronautical Terms, third edition'', page 305. Aviation Supplies & Academics, ...
s of the wing were so thin (0.016 in/0.41 mm) and so sharp that they presented a hazard to ground crews, and protective guards had to be installed during ground operations. The thinness of the wings meant that fuel tanks and
landing gear Landing gear is the undercarriage of an aircraft or spacecraft that is used for takeoff or landing. For aircraft it is generally needed for both. It was also formerly called ''alighting gear'' by some manufacturers, such as the Glenn L. Martin ...
had to be contained in the fuselage. The
hydraulic Hydraulics (from Greek: Υδραυλική) is a technology and applied science using engineering, chemistry, and other sciences involving the mechanical properties and use of liquids. At a very basic level, hydraulics is the liquid counter ...
actuators An actuator is a component of a machine that is responsible for moving and controlling a mechanism or system, for example by opening a valve. In simple terms, it is a "mover". An actuator requires a control device (controlled by control signal) an ...
driving the
ailerons An aileron (French for "little wing" or "fin") is a hinged flight control surface usually forming part of the trailing edge of each wing of a fixed-wing aircraft. Ailerons are used in pairs to control the aircraft in Flight dynamics, roll (or ...
were only one inch (25 mm) thick to fit into the available space and were known as
Piccolo The piccolo ( ; Italian for 'small') is a half-size flute and a member of the woodwind family of musical instruments. Sometimes referred to as a "baby flute" the modern piccolo has similar fingerings as the standard transverse flute, but the so ...
actuators because of their resemblance to this musical instrument. The wings had electrically driven leading and trailing edge flaps to increase lift at low speed. The XF-104 did not feature the
Boundary Layer Control System Blown flaps, or jet flaps, are powered aerodynamic high-lift devices used on the wings of certain aircraft to improve their low-speed flight characteristics. They use air blown through nozzles to shape the airflow over the rear edge of the wing, d ...
of the production aircraft.Bowman 2000, p. 28.


Tail fin

After extensive
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testing, the
stabilator A stabilator is a fully movable aircraft horizontal stabilizer. It serves the usual functions of longitudinal stability, control and stick force requirements otherwise performed by the separate parts of a conventional horizontal stabilizer and el ...
was mounted at the top of the fin for optimum stability and control about the pitch axis.Bowman 2000, p. 28. Because the vertical tail fin was only slightly shorter than the length of each wing and nearly as aerodynamically effective, it could act as a wing on
rudder A rudder is a primary control surface used to steer a ship, boat, submarine, hovercraft, aircraft, or other vehicle that moves through a fluid medium (generally aircraft, air or watercraft, water). On an aircraft the rudder is used primarily to ...
application (a phenomenon known as "
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"). To offset this effect, the wings were angled downward to give 10° anhedral. The rudder was manually operated and supplemented by a small
yaw damper A yaw damper (sometimes referred to as a stability augmentation system) is a system used to reduce (or damp) the undesirable tendencies of an aircraft to oscillate in a repetitive rolling and yawing motion, a phenomenon known as the Dutch roll. ...
surface mounted at the bottom of the fin.Bowman 2000, p. 28.


Fuselage

The
fuselage The fuselage (; from the French ''fuselé'' "spindle-shaped") is an aircraft's main body section. It holds crew, passengers, or cargo. In single-engine aircraft, it will usually contain an engine as well, although in some amphibious aircraft t ...
of the XF-104 had a high
fineness ratio In naval architecture and aerospace engineering, the fineness ratio is the ratio of the length of a body to its maximum width. Shapes that are short and wide have a low fineness ratio, those that are long and narrow have high fineness ratios. A ...
, i.e., tapering sharply towards the nose, and a small frontal area of . The fuselage was tightly packed, containing the
cockpit A cockpit or flight deck is the area, usually near the front of an aircraft or spacecraft, from which a Pilot in command, pilot controls the aircraft. The cockpit of an aircraft contains flight instruments on an instrument panel, and the ...
,
avionics Avionics (a blend word, blend of ''aviation'' and ''electronics'') are the Electronics, electronic systems used on aircraft. Avionic systems include communications, Air navigation, navigation, the display and management of multiple systems, ...
, cannon, all internal fuel, landing gear, and engine.Bowman 2000, p. 29. The air intakes, designed by Ben Rich, were of fixed geometry without inlet cones, since the J65-powered aircraft was incapable of Mach 2 performance. They were similar to those of the
F-94 Starfire The Lockheed F-94 Starfire was a first-generation jet powered all-weather, day/night interceptor of the United States Air Force. A twin-seat craft, it was developed from the Lockheed T-33 Shooting Star trainer in the late 1940s. It reached ope ...
, being mounted slightly away from the fuselage, with an inner splitter plate for the
boundary layer In physics and fluid mechanics, a boundary layer is the thin layer of fluid in the immediate vicinity of a bounding surface formed by the fluid flowing along the surface. The fluid's interaction with the wall induces a no-slip boundary condi ...
bleed air. The combination of these features provided extremely low drag except at high
angle of attack In fluid dynamics, angle of attack (AOA, α, or \alpha) is the angle between a reference line on a body (often the chord line of an airfoil) and the vector representing the relative motion between the body and the fluid through which it is m ...
, at which point
induced drag In aerodynamics, lift-induced drag, induced drag, vortex drag, or sometimes drag due to lift, is an aerodynamic drag force that occurs whenever a moving object redirects the airflow coming at it. This drag force occurs in airplanes due to wings or ...
became very high.


Ejection seat

The XF-104 featured an unusual downward-ejecting
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seat. It was feared that contemporary ejection seat designs would not have enough explosive power to clear the high "T" tail assembly. In the event of the seat not firing, it was possible to manually release the lower fuselage hatch and then exit the aircraft via gravity. The F-104 series aircraft would later convert to upward-ejecting seats but the fuselage hatch was retained as a useful maintenance feature.Bowman 2000, p. 33.


Operational history


Testing and evaluation


First flights

The first XF-104 (Lockheed 083-1001, s/n ''53-7786'') was transported to
Edwards AFB Edwards Air Force Base (AFB) is a United States Air Force installation in California. Most of the base sits in Kern County, but its eastern end is in San Bernardino County and a southern arm is in Los Angeles County. The hub of the base is Ed ...
amidst high secrecy during the night of 24–25 February, where Lockheed test pilot
Tony LeVier Anthony W. LeVier (February 14, 1913 – February 6, 1998) was an American air racer and test pilot for the Lockheed Corporation from the 1940s to the 1970s. Early life Born Anthony Puck in Duluth, Minnesota, his father died while he was still ...
was to do the initial testing.Bowman 2000, p. 32. On 28 February 1954, the XF-104 made a planned hop of about five feet off the ground during a high-speed taxi, but its first official flight took place on 4 March. During that flight, the landing gear did not retract, and LeVier landed after a low-speed flight of about 20 minutes.Jenkins and Landis 2008, p. 168. Adjustments and further flights discovered that the problem was low pressure in the hydraulic system. Bad weather kept the XF-104 on the ground until 26 March, when further flights were carried out with the landing gear retracting normally. The second prototype (Lockheed 083-1002, s/n ''53-7787''), fitted with the afterburning J65 from the start, first flew on 5 October. Since it was to be the armament test bed, it was fitted with the 20 mm (.79 in)
M61 Vulcan The M61 Vulcan is a hydraulically, electrically, or pneumatically driven, six-barrel, air-cooled, electrically fired Gatling-style rotary cannon which fires rounds at an extremely high rate (typically 6,000 rounds per minute). The M61 and its ...
cannon and was equipped with an AN/ASG-14T-1 fire control system.Upton 2003, p. 38. XF-104 #2 achieved a top speed of Mach 1.79 at on 25 March 1955, piloted by Lockheed test pilot J. Ray Goudey. This was the highest speed achieved by the XF-104.Bowman 2000, p. 29.


Performance

XF-104 #1 was subsonic in level flight when powered by the non-afterburning J65, but Mach 1 could be easily exceeded during a slight descent. In July 1954, the J65-B-3 was replaced by the afterburning J65-W-7 turbojet. With this engine installed, the performance of the XF-104 was greatly improved. Maximum level speed was Mach 1.49 at , and an
altitude Altitude or height (also sometimes known as depth) is a distance measurement, usually in the vertical or "up" direction, between a reference datum and a point or object. The exact definition and reference datum varies according to the context ...
of could be attained in a zoom climb, while Mach 1.6 could be attained in a dive. The first XF-104 was accepted by the USAF in November 1955.


Firing tests

Initial aerial firing tests with the Vulcan cannon on the second aircraft were successful, but on 17 December, there was an explosion during a firing burstBowman 2000, p. 35. and the J65 engine suffered severe
compressor stall A compressor stall is a local disruption of the airflow in the compressor of a gas turbine or turbocharger. A stall that results in the complete disruption of the airflow through the compressor is referred to as a compressor surge. The severity of t ...
s. Tony LeVier immediately shut down the engine and glided back to make a successful
deadstick landing A deadstick landing, also called a dead-stick landing, is a type of forced landing when an aircraft loses all of its propulsive power and is forced to land. The "stick" does not refer to the flight controls, which in most aircraft are either ful ...
at
Rogers Dry Lake Rogers Dry Lake is an endorheic desert salt pan in the Mojave Desert of Kern County, California. The lake derives its name from the Anglicization from the Spanish name, Rodriguez Dry Lake. It is the central part of Edwards Air Force Base as its ...
. An investigation later showed that one of the 20 mm cannon rounds had exploded in the
breech Breech may refer to: * Breech (firearms), the opening at the rear of a gun barrel where the cartridge is inserted in a breech-loading weapon * breech, the lower part of a pulley block * breech, the penetration of a boiler where exhaust gases leav ...
, blowing the bolt out the rear of the gun and through the structure into the forward fuselage fuel cell. Jet fuel had run into the gun bay, and leaked out of the compartment door seals and into the left engine air intake. The engine immediately flooded with fuel, causing the compressor stalls.


Crashes

XF-104 ''53-7786'' was lost in a crash on 11 July 1957 when it developed an uncontrollable fin flutter while flying chase for F-104A flight tests. The entire tail group was ripped from the airframe, and Lockheed test pilot Bill Park was forced to eject. Fin flutter was a known problem and the aircraft had been limited to speeds of no more than Mach 0.95 at the time of the accident. Tony LeVier had attempted to have the aircraft removed from flight status and placed in a museum, arguing that its performance was not suitable for chase duties.Bowman 2000, p. 35.Upton 2003, p. 45.Pace 1992, p. 22. XF-104 ''53-7787'' was lost on 14 April 1955 after accumulating over 1,000 flying hours when test pilot
Herman Salmon Herman Richard Salmon (July 11, 1913 – June 22, 1980), nicknamed "Fish", was a barnstormer, air racer, and test pilot for the Lockheed Corporation. Biography Early life Salmon was born in 1913 in Milwaukee, Wisconsin, to Pennsylvania-bo ...
was forced to eject during gun firing trials at . The gun malfunctioned during a test firing, and severe vibrations began to build up which knocked loose the ejection hatch below the cockpit.
Cabin pressure Cabin pressurization is a process in which conditioned air is pumped into the cabin of an aircraft or spacecraft in order to create a safe and comfortable environment for passengers and crew flying at high altitudes. For aircraft, this air is ...
was lost with Salmon's
pressure suit A pressure suit is a protective suit worn by high-altitude pilots who may fly at altitudes where the air pressure is too low for an unprotected person to survive, even breathing pure oxygen at positive pressure. Such suits may be either full-pr ...
inflating and covering his face so that he could not see. Recalling LeVier's harrowing experience with the exploding cannon shell the previous December, Salmon believed that the same thing had happened to him and that he had no option but to eject. He later found out that he could have saved ''53-7787'' by bringing it down to a lower
altitude Altitude or height (also sometimes known as depth) is a distance measurement, usually in the vertical or "up" direction, between a reference datum and a point or object. The exact definition and reference datum varies according to the context ...
and waiting for his pressure suit to deflate. With the loss of the armament
testbed A testbed (also spelled test bed) is a platform for conducting rigorous, transparent, and replicable testing of scientific theories, computational tools, and new technologies. The term is used across many disciplines to describe experimental rese ...
, Lockheed engineers were forced to find an alternative, and armament trials were continued on a modified
Lockheed F-94C Starfire The Lockheed F-94 Starfire was a first-generation jet powered all-weather, day/night interceptor of the United States Air Force. A twin-seat craft, it was developed from the Lockheed T-33 Shooting Star trainer in the late 1940s. It reached ope ...
.Pace 1992, p. 20. The two XF-104s amassed an approximate total of 2,500 flight hours.


Testing conclusions

Flight testing proved that performance estimates were accurate and that even when fitted with the low powered J65 engine, the XF-104 flew faster than the other
Century Series The Century Series is a popular name for a group of US fighter aircraft representing models designated between F-100 and F-106 which went into full production. They included the first successful supersonic aircraft designs in the United State ...
fighters being developed at the time. The XF-104's ceiling at was higher than predicted, and it exceeded estimated speed and drag figures by two to three percent. It was noted however that the low thrust of the J65 engine did not enable the full performance potential of the type to be realized. A number of minor problems surfaced, but were readily fixed. The
yaw damper A yaw damper (sometimes referred to as a stability augmentation system) is a system used to reduce (or damp) the undesirable tendencies of an aircraft to oscillate in a repetitive rolling and yawing motion, a phenomenon known as the Dutch roll. ...
of the XF-104 was found to be ineffective and the rudder did not positively center; these problems were corrected by revising the rudder control system.Pace 1992, p. 20. The unpowered rudder did not provide adequate directional control at high air speeds, which problem was fixed by using hydraulic power on all subsequent versions of the F-104; and some concern was expressed over poor subsonic maneuverability at higher altitudes.Pace 1992, p. 20. During a later interview, Kelly Johnson was asked about his opinion on the aircraft. "Did it come up to my designs? In terms of performance, yes. In terms of engine, we went through a great many engine problems, not with the J65s but with the J79s." For his part in designing the F-104 airframe, Johnson was jointly awarded the
Collier Trophy The Robert J. Collier Trophy is an annual aviation award administered by the U.S. National Aeronautic Association (NAA), presented to those who have made "the greatest achievement in aeronautics or astronautics in America, with respect to im ...
in 1958, sharing the honor with General Electric (engine) and the U.S. Air Force (Flight Records).Greenfield, Art
"Collier Trophy winners, 1950–1959."
''National Aeronautic Association''. Retrieved: 26 June 2011.


Specifications (XF-104)


See also


References

;Notes ;Bibliography * Bowman, Martin W. ''Lockheed F-104 Starfighter''. Ramsbury, Marlborough, Wiltshire, UK: The Crowood Press Ltd., 2000. . * Drendel, Lou. ''F-104 Starfighter in action (Aircraft No. 27)''. Carrollton, Texas: Squadron/Signal Publications, 1976. . * Jenkins, Dennis R. and Tony R. Landis. ''Experimental & Prototype U.S. Air Force Jet Fighters.'' North Branch, Minnesota: Specialty Press, 2008. . * Kinzey, Bert ''F-104 Starfighter in detail & scale''. Blue Ridge Summit, Pennsylvania: TAB books, 1991. . * Pace, Steve. ''F-104 Starfighter: Design, Development and Worldwide Operations of the First Operational Mach 2 Fighter''. St. Paul, Minnesota: Motorbooks International, 1992. . * Pace, Steve. ''X-Fighters: USAF Experimental and Prototype Fighters, XP-59 to YF-23''. St. Paul, Minnesota: Motorbooks International, 1991. . * Reed, Arthur. ''F-104 Starfighter – Modern Combat Aircraft 9''. London: Ian Allan Ltd., 1981. . * Upton, Jim. ''Warbird Tech - Lockheed F-104 Starfighter''. North Branch, Minnesota: Specialty Press, 2003. .


External links


XF-104 page
on USAF National Museum site
First flight of the XF-104
on YouTube.



''Flight International''.

on Vectorsite.net {{USAF fighters F-104, X
Lockheed F-104 The Lockheed F-104 Starfighter is an American single-engine, supersonic air superiority fighter 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 fig ...
1950s United States experimental aircraft Single-engined jet aircraft XF-104 Mid-wing aircraft