Lockheed XF-104 Starfighter

Last updated

XF-104 Starfighter
Lockheed XF-104 (modified).jpg
First prototype XF-104 53-7786
Role Interceptor prototype
Manufacturer Lockheed Corporation
Designer Clarence L. "Kelly" Johnson
First flight4 March 1954
Number built2
Variants Lockheed F-104 Starfighter
Lockheed NF-104A
Canadair CF-104
Aeritalia F-104S
CL-1200 Lancer/X-27

The Lockheed XF-104 Starfighter was a single-engine, high-performance, supersonic interceptor prototype for a United States Air Force (USAF) series of lightweight and simple fighters. Only two aircraft were built; one aircraft was used primarily for aerodynamic research and the other served as an armament testbed, both aircraft being destroyed in accidents during testing. [1] The XF-104s were forerunners of over 2,500 production Lockheed F-104 Starfighters.

Contents

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 Jordan, Turkey, and Japan.

Development

Original requirement

Clarence L. "Kelly" Johnson, chief engineer at Lockheed's Skunk Works, visited Korea 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 Sabres, 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. [2] One pilot in particular, Colonel Gabby Gabreski 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". [2]

An original Johnson sketch Kelly sketch.jpg
An original Johnson sketch

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. [3]

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 Republic AP-55, an improved version of its prototype XF-91 Thunderceptor; the North American NA-212, which would eventually evolve into the F-107; and the Northrop N-102 Fang, a new General Electric J79-powered design.

Selected design

Although all were interesting, Lockheed had an insurmountable lead and was granted a development contract in March 1953. [3] Test data from the earlier Lockheed X-7 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. [4] [5] Experience gained from the Douglas X-3 Stiletto was also used in the design phase of the XF-104. [6] 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. [7]

Prototypes

The wooden mock-up 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, a licensed built version of the Armstrong Siddeley Sapphire. Construction of the first prototype XF-104 (US serial number 53-7786, Buzz number FG-786) began in summer 1953 at Lockheed's Burbank, California factory. [8] This aircraft was powered by a non-afterburning Buick-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. [5] Construction of the second prototype (s/n 53-7787) proceeded at a slower pace. [8]

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. [9]

Visible changes from the XF-104 to production versions of the Starfighter include a longer fuselage (to accommodate the J79 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. [3] [10] [11] Production aircraft would also feature a redesigned fin structure using stainless steel spars to eliminate the flutter problem. [12] 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. [9]

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 efficient airframe possible around a single powerful engine. The emphasis was on minimizing drag and mass. [13]

Wing design

The XF-104 had a radical wing design. Most supersonic jets use a swept or delta wing. This allows a reasonable balance between aerodynamic performance, lift, and internal space for fuel and equipment. However the most efficient shape for high-speed, supersonic flight had been found to be a small, straight, mid-mounted, trapezoidal wing of low aspect ratio and high wing loading. The wing was extremely thin, with a thickness-to-chord ratio of only 3.4%. [14] The leading edges 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 had to be contained in the fuselage. The hydraulic actuators driving the ailerons were only one inch (25 mm) thick to fit into the available space and were known as Piccolo 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 of the production aircraft. [15]

Wooden mock-up Xf-104 mock-up.jpg
Wooden mock-up

Tail fin

After extensive wind tunnel testing, the stabilator was mounted at the top of the fin for optimum stability and control about the pitch axis. [15] 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 application (a phenomenon known as "Dutch roll"). 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 surface mounted at the bottom of the fin. [15]

Fuselage

The fuselage of the XF-104 had a high fineness ratio, i.e., tapering sharply towards the nose, and a small frontal area of 25 sq ft (2.3 m2). [16] The fuselage was tightly packed, containing the cockpit, avionics, cannon, all internal fuel, landing gear, and engine. [13] 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, being mounted slightly away from the fuselage, with an inner splitter plate for the boundary layer bleed air. The combination of these features provided extremely low drag except at high angle of attack, at which point induced drag became very high.

Ejection seat

The XF-104 featured an unusual downward-ejecting Stanley B 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. [1]

Operational history

Testing and evaluation

Tony LeVier poses on an XF-104. Note the wingtip tanks Lockheed XF-104 060928-F-1234S-001.jpg
Tony LeVier poses on an XF-104. Note the wingtip tanks

First flights

The first XF-104 (Lockheed 083-1001, s/n 53-7786) was transported to Edwards AFB amidst high secrecy during the night of 24–25 February, where Lockheed test pilot Tony LeVier was to do the initial testing. [3] 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. [17] During that flight, the landing gear did not retract, and LeVier landed after a low-speed flight of about 20 minutes. [8] Adjustments and further flights discovered that the problem was low pressure in the hydraulic system. [8] Bad weather kept the XF-104 on the ground until 26 March, when further flights were carried out with the landing gear retracting normally. [8]

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 cannon and was equipped with an AN/ASG-14T-1 fire control system. [10] XF-104 #2 achieved a top speed of Mach 1.79 at 60,000 feet (18,000 m) on 25 March 1955, piloted by Lockheed test pilot J. Ray Goudey. This was the highest speed achieved by the XF-104. [8] [13]

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 41,000 ft (12,000 m), and an altitude of 55,000 ft (17,000 m) 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. [8]

M61 Vulcan Vulcan1.jpg
M61 Vulcan

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 burst [9] and the J65 engine suffered severe compressor stalls. Tony LeVier immediately shut down the engine and glided back to make a successful deadstick landing at Rogers Dry Lake. An investigation later showed that one of the 20 mm cannon rounds had exploded in the breech, 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. [18]

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. [9] [12] [19]

XF-104 53-7787 was lost on 14 April 1955 after accumulating over 1,000 flying hours [9] [20] when test pilot Herman Salmon was forced to eject during gun firing trials at 50,000 ft (15,000 m). 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 was lost with Salmon's pressure suit 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 and waiting for his pressure suit to deflate. With the loss of the armament testbed, Lockheed engineers were forced to find an alternative, and armament trials were continued on a modified Lockheed F-94C Starfire. [21] The two XF-104s amassed an approximate total of 2,500 flight hours. [8]

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 fighters being developed at the time. The XF-104's ceiling at 60,000 ft (18,000 m) was 7,000 ft (2,100 m) higher than predicted, and it exceeded estimated speed and drag figures by two to three percent. [22] 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. [9]

XF-104 s/n 53-7786 with early models of the F-100, F-101, F-102 and F-105 Century.jpg
XF-104 s/n 53-7786 with early models of the F-100, F-101, F-102 and F-105

A number of minor problems surfaced, but were readily fixed. The yaw damper 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. [21] The unpowered rudder did not provide adequate directional control at high air speeds, with the problem being 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. [21]

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." [23] For his part in designing the F-104 airframe, Johnson was jointly awarded the Collier Trophy in 1958, sharing the honor with General Electric (engine) and the U.S. Air Force (Flight Records). [24]

Specifications (XF-104)

XF-104 3-view Lockheed XF-104 Starfighter drawing.jpg
XF-104 3-view

Data fromBowman and Drendel. [1] [25]

General characteristics

Performance

Armament

See also

Related development

Aircraft of comparable role, configuration, and era

Related lists

Related Research Articles

<span class="mw-page-title-main">Lockheed P-80 Shooting Star</span> Fighter aircraft; first jet fighter in United States operational service

The Lockheed P-80 Shooting Star was the first jet fighter used operationally by the United States Army Air Forces (USAAF) during World War II. Designed and built by Lockheed in 1943 and delivered just 143 days from the start of design, production models were flying, and two pre-production models did see very limited service in Italy just before the end of World War II. Designed with straight wings, the type saw extensive combat in Korea with the United States Air Force (USAF) as the F-80.

<span class="mw-page-title-main">Lockheed F-104 Starfighter</span> 1956 fighter aircraft family by Lockheed

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 fighter aircraft for the United States Air Force (USAF), 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.

<span class="mw-page-title-main">McDonnell XF-88 Voodoo</span> Prototype fighter aircraft

The McDonnell XF-88 Voodoo was a long-range, twinjet fighter aircraft with swept wings designed for the United States Air Force. Although it never entered production, its design was adapted for the subsequent supersonic F-101 Voodoo.

<span class="mw-page-title-main">Republic XF-91 Thunderceptor</span> Experimental interceptor aircraft

The Republic XF-91 Thunderceptor 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 for added thrust during climb and interception. The design was largely obsolete by the time it was completed due to the rapidly increasing performance of contemporary jet engines, and only two prototypes were built. One of these was the first American fighter to exceed Mach 1 in level flight.

<span class="mw-page-title-main">McDonnell XF-85 Goblin</span> Experimental parasite fighter

The McDonnell XF-85 Goblin is an American prototype fighter aircraft conceived during World War II by McDonnell Aircraft. It was intended to deploy from the bomb bay of the Convair B-36 bomber as a parasite fighter. The XF-85's intended role was to defend bombers from hostile interceptor aircraft, a need demonstrated during World War II. McDonnell built two prototypes before the Air Force (USAAF) terminated the program.

<span class="mw-page-title-main">Century Series</span> Group of US fighter aircraft between designations F-100 and F-106

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 States Air Force's service, which remained in active service well into the 1970s and 1980s with the Air Force Reserve and Air National Guard. Three later variants, the QF-100, QF-102, and QF-106, also continued in service, primarily as aerial target drones, until the late 1990s. The F-104G stayed in service with the Italian military until 2004. The NASA airborne science program maintains a group of F-104G in airworthy condition for use as test platforms and chase aircraft.

<span class="mw-page-title-main">Northrop YF-23</span> Prototype fighter aircraft for the US Air Force Advanced Tactical Fighter program

The Northrop/McDonnell Douglas YF-23 is an American single-seat, twin-engine, supersonic stealth fighter aircraft technology demonstrator designed for the United States Air Force (USAF). The design was a finalist in the USAF's Advanced Tactical Fighter (ATF) competition, battling the Lockheed YF-22 for a production contract. Two YF-23 prototypes were built.

<span class="mw-page-title-main">Lockheed YF-12</span> American prototype interceptor aircraft

The Lockheed YF-12 was an American Mach 3+ capable, high-altitude interceptor prototype, developed and manufactured by American aerospace company Lockheed Corporation.

<span class="mw-page-title-main">Douglas X-3 Stiletto</span> Experimental aircraft to test sustained supersonic flight

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 aircraft suitable for sustained supersonic speeds, which included the first use of titanium in major airframe components. Douglas designed the X-3 with the goal of a maximum speed of approximately 2,000 mph (3,200 km/h), but it was seriously underpowered for this purpose and could not even exceed Mach 1 in level flight. Although the research aircraft was a disappointment, Lockheed designers used data from the X-3 tests for the Lockheed F-104 Starfighter which used a similar trapezoidal wing design in a successful Mach 2 fighter.

<span class="mw-page-title-main">Lockheed YF-22</span> Prototype fighter aircraft for the US Air Force Advanced Tactical Fighter program

The Lockheed/Boeing/General Dynamics YF-22 is an American single-seat, twin-engine fighter aircraft technology demonstrator designed for the United States Air Force (USAF). The design was a finalist in the USAF's Advanced Tactical Fighter competition, and two prototypes were built for the demonstration/validation phase of the competition. The YF-22 won the contest against the Northrop YF-23, and the design was developed into the Lockheed Martin F-22 Raptor. The YF-22 has a similar aerodynamic layout and configuration as the F-22, but with differences in the position and design of the cockpit, tail fins and wings, and in internal structural layout.

<span class="mw-page-title-main">Republic XF-103</span> Cancelled American military plane project of the 1940s-1950s

The Republic XF-103 was an American project to develop a powerful missile-armed interceptor aircraft capable of destroying Soviet bombers while flying at speeds as high as Mach 3. Despite a prolonged development, it never progressed past the mockup stage.

<span class="mw-page-title-main">Convair XF-92</span> Experimental interceptor aircraft

The Convair XF-92 was an American, delta wing, first-generation jet prototype. Originally conceived as a point-defence interceptor, the design was later used purely for experimental purposes and only one was built. However, it led Convair to use the delta-wing on a number of designs, including the F-102 Delta Dagger, F-106 Delta Dart, B-58 Hustler, the US Navy's F2Y Sea Dart as well as the VTOL FY Pogo.

<span class="mw-page-title-main">North American F-107</span> 1956 prototype fighter aircraft

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, based on the F-100 Super Sabre. It incorporated many innovations and radical design features, notably the over-fuselage air intakes. The competition was eventually won by the Republic F-105 Thunderchief, and two of the three F-107 prototypes ended their lives as test aircraft. One is on display at the National Museum of the United States Air Force and a second at Pima Air and Space Museum.

<span class="mw-page-title-main">Lockheed CL-1200 Lancer</span> American fighter proposal

The Lockheed CL-1200 Lancer was a late 1960s company-funded proposal for a fighter aircraft based on the Lockheed F-104 Starfighter. The CL-1200 was conceived and marketed mainly for and to non-US military services, as an export product. As such it would have competed with combat-proven designs like the Dassault Mirage III, McDonnell Douglas F-4 Phantom II, Mikoyan-Gurevich MiG-21, and Northrop F-5E Tiger II. The CL-1200 competed unsuccessfully against proposed fourth generation designs, under the US government's Lightweight Fighter program, which would eventually result in the General Dynamics F-16 and Northrop F-17 Cobra.

<span class="mw-page-title-main">Wright J65</span> Turbojet aircraft engine

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.

<span class="mw-page-title-main">Republic XF-84H Thunderscreech</span> Experimental turboprop aircraft

The Republic XF-84H "Thunderscreech" was an American experimental turboprop aircraft derived from the F-84F Thunderstreak. Powered by a turbine engine that was mated to a supersonic propeller, the XF-84H had the potential of setting the unofficial air speed record for propeller-driven aircraft, but was unable to overcome aerodynamic deficiencies and engine reliability problems, resulting in the program's cancellation. Its name, Thunderscreech, is a reference to its extremely loud supersonic propeller.

<span class="mw-page-title-main">Aeritalia F-104S Starfighter</span> Italian fighter aircraft

The Aeritalia F-104S Starfighter was a licensed production Italian version of the Lockheed F-104 Starfighter, which served in the Italian Air Force, and was its mainstay from the late 1960s until the beginning of the 21st century. The F-104S also served in the Turkish Air Force until the mid-1990s. The F-104S was the final development of the Starfighter line.

<span class="mw-page-title-main">Lockheed NF-104A</span> Astronaut training aircraft conversion

The Lockheed NF-104A was an American mixed-power, high-performance, supersonic aerospace trainer that served as a low-cost astronaut training vehicle for the North American X-15 and projected Boeing X-20 Dyna-Soar programs.

<span class="mw-page-title-main">Northrop N-102 Fang</span> Type of aircraft

The Northrop N-102 Fang was a fighter aircraft design created by Northrop Corporation and proposed to the United States Air Force in 1953. The Fang was explicitly designed as a ”light” or “lightweight fighter” in direct response to what Northrop saw as the ever-increasing weight, size, complexity, and cost of Western fighter designs. While the Fang was ultimately overlooked in-favor of the Lockheed F-104 Starfighter, Northrop’s interest in the lightweight fighter concept would ultimately come to fruition with the F-5 Freedom Fighter, itself spawning a moderately successful fighter family.

References

Notes
  1. 1 2 3 4 Bowman 2000, p. 33.
  2. 1 2 Bowman 2000, p. 26.
  3. 1 2 3 4 Bowman 2000, p. 32.
  4. ↑ Reed 1981, p. 10.
  5. 1 2 Upton 2003, p. 13.
  6. ↑ Bowman 2000, p. 27.
  7. ↑ Upton 2003, p. 14.
  8. 1 2 3 4 5 6 7 8 Jenkins and Landis 2008, p. 168.
  9. 1 2 3 4 5 6 Bowman 2000, p. 35.
  10. 1 2 Upton 2003, p. 38.
  11. ↑ Gunston, W. L., ed. "F-104: Holder of the Absolute Records for Speed and Altitude." Flight International, 30 May 1958, p. 743. Retrieved: 29 June 2011.
  12. 1 2 Upton 2003, p. 45.
  13. 1 2 3 Bowman 2000, p. 29.
  14. ↑ "F-104: Holder of the Absolute Records for Speed and Altitude". Flight International. 30 May 1958. Archived from the original on 14 May 2013. Retrieved 6 July 2011.
  15. 1 2 3 Bowman 2000, p. 28.
  16. ↑ Upton 2003, p. 17.
  17. ↑ Pace 1992, p. 17.
  18. ↑ Gunston. W. L., ed. "Starfighter: Lockheed's Mach 2 Fighter for the U.S.A.F." Flight International, 20 April 1956, p. 442. Retrieved: 28 June 2011.
  19. ↑ Pace 1992, p. 22.
  20. ↑ Kinzey 1991, p. 6.
  21. 1 2 3 Pace 1992, p. 20.
  22. ↑ Kinzey 1991, p. 4.
  23. ↑ Reed 1981, p. 13.
  24. ↑ Greenfield, Art. "Collier Trophy winners, 1950–1959." Archived December 11, 2008, at the Wayback Machine National Aeronautic Association. Retrieved: 26 June 2011.
  25. ↑ Drendel 1976, p. 10.
  26. ↑ Lednicer, David. "The Incomplete Guide to Airfoil Usage". m-selig.ae.illinois.edu. Retrieved 16 April 2019.
Bibliography
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.