Misplaced Pages

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114-544: The Republic F-84 Thunderjet is an American turbojet fighter-bomber aircraft. Originating as a 1944 United States Army Air Forces (USAAF) proposal for a "day fighter", the F-84 first flew in 1946. Although it entered service in 1947, the Thunderjet was plagued by so many structural and engine problems that a 1948 U.S. Air Force review declared it unable to execute any aspect of its intended mission and considered canceling

228-416: A i r + m ˙ f ) V j − m ˙ a i r V {\displaystyle F_{N}=({\dot {m}}_{air}+{\dot {m}}_{f})V_{j}-{\dot {m}}_{air}V} where: If the speed of the jet is equal to sonic velocity the nozzle is said to be " choked ". If the nozzle is choked, the pressure at the nozzle exit plane

342-705: A Mikoyan-Gurevich MiG-15 in Korea, although by this time the F-80 (as it was redesignated in June 1948) was already considered obsolete. Starting with the P-80, Lockheed's secret development work was conducted by its Advanced Development Division, more commonly known as the Skunk works . The name was taken from Al Capp 's comic strip Li'l Abner . This organization has become famous and spawned many successful Lockheed designs, including

456-701: A nuclear weapon , the Mark 7 nuclear bomb . Modified F-84s were used in several unusual projects, including the FICON and Tom-Tom dockings to the B-29 Superfortress and B-36 bomber motherships, and the experimental XF-84H Thunderscreech turboprop . The F-84 nomenclature can be somewhat confusing. The straight-wing F-84A to F-84E and F-84G models were called the Thunderjet. The F-84F Thunderstreak and RF-84F Thunderflash were different airplanes with swept wings. The XF-84H Thunderscreech (not its official name)

570-592: A turbojet -powered replacement for the P-47 Thunderbolt piston-engined fighter aircraft . The initial attempts to redesign the P-47 to accommodate a jet engine proved futile due to the large cross-section of the Thunderbolt's fuselage . Instead, Kartveli and his team designed a new aircraft with a much-slimmer fuselage housing an axial compressor turbojet engine in the rear fuselage, and an air intake in

684-487: A distinctive framed canopy (also retrofitted to earlier types), and the ability to carry a single Mark 7 nuclear bomb . The F-84G entered service in 1951, although deliveries were slowed by shortages of engines. Production continued until July 1953 with 3,025 F-84Gs delivered, with 789 going to the USAF and 2,236 to US allies as part of US military aid. The F-84G was retired from the USAF in mid-1960. Typical of most early jets,

798-585: A gas turbine to power an aircraft was filed in 1921 by Frenchman Maxime Guillaume . His engine was to be an axial-flow turbojet, but was never constructed, as it would have required considerable advances over the state of the art in compressors. In 1928, British RAF College Cranwell cadet Frank Whittle formally submitted his ideas for a turbojet to his superiors. In October 1929 he developed his ideas further. On 16 January 1930 in England, Whittle submitted his first patent (granted in 1932). The patent showed

912-542: A landing field, lengthening flights. The increase in reliability that came with the turbojet enabled three- and two-engine designs, and more direct long-distance flights. High-temperature alloys were a reverse salient , a key technology that dragged progress on jet engines. Non-UK jet engines built in the 1930s and 1940s had to be overhauled every 10 or 20 hours due to creep failure and other types of damage to blades. British engines, however, utilised Nimonic alloys which allowed extended use without overhaul, engines such as

1026-508: A leafy texture. Lockheed ranked tenth among United States corporations in the value of wartime production contracts. All told, Lockheed and its subsidiary Vega produced 19,278 aircraft during World War II, representing six percent of war production, including 2,600 Venturas , 2,750 Boeing B-17 Flying Fortress bombers (built under license from Boeing ), 2,900 Hudson bombers, and 9,000 Lightnings. During World War II, Lockheed, in cooperation with Trans-World Airlines (TWA), had developed

1140-488: A problem. Thanks to the thick straight wing the Thunderjet rapidly reached its Mach 0.82 limitation at full throttle and low altitude. The aircraft had sufficient power to fly faster, but exceeding the Mach limit at low altitudes resulted in a violent pitch-up and structural failure causing the wings to break off. Above 15,000 ft (4,600 m), the F-84 could be flown faster but at the expense of severe buffeting. However,

1254-643: A prototype for the civil market, but folded in 1920 due to the flood of surplus aircraft deflating the market after World War I . Allan went into the real estate market while Malcolm had meanwhile formed a successful company marketing brake systems for automobiles. On December 13, 1926, Allan Loughead, John Northrop , Kenneth Kay and Fred Keeler secured funding to form the Lockheed Aircraft Company ( spelled phonetically to prevent mispronunciation) in Hollywood. This new company used some of

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1368-459: A second generation SST engine using the 593 core were done more than three years before Concorde entered service. They evaluated bypass engines with bypass ratios between 0.1 and 1.0 to give improved take-off and cruising performance. Nevertheless, the 593 met all the requirements of the Concorde programme. Estimates made in 1964 for the Concorde design at Mach 2.2 showed the penalty in range for

1482-411: A significant impact on commercial aviation . Aside from giving faster flight speeds turbojets had greater reliability than piston engines, with some models demonstrating dispatch reliability rating in excess of 99.9%. Pre-jet commercial aircraft were designed with as many as four engines in part because of concerns over in-flight failures. Overseas flight paths were plotted to keep planes within an hour of

1596-523: A similar standard to the F-84D. Despite the resultant improvements, both the F-84B and F-84C were withdrawn from service during 1952. The structural improvements were factory-implemented in the F-84D, which entered service in 1949. Wings were covered with thicker aluminum skin, the fuel system was winterized and capable of using JP-4 fuel, and a more powerful J35-A-17D engine with 5,000 lbf (22.24 kN)

1710-544: A slate of his own choosing, since he was the largest investor. His board nominations included former Texas Senator John Tower , the onetime chairman of the Armed Services Committee , and Admiral Elmo Zumwalt Jr ., a former Chief of Naval Operations. Simmons had first begun accumulating Lockheed stock in early 1989 when deep Pentagon cuts to the defense budget had driven down prices of military contractor stocks, and analysts had not believed he would attempt

1824-405: A small helicopter engine compressor rotates around 50,000 RPM. Turbojets supply bleed air from the compressor to the aircraft for the operation of various sub-systems. Examples include the environmental control system , anti-icing , and fuel tank pressurization. The engine itself needs air at various pressures and flow rates to keep it running. This air comes from the compressor, and without it,

1938-448: A testament to its long takeoff rolls. F-84 lore stated that all aircraft were equipped with a "sniffer" device that, upon passing takeoff safety speed , would look for the dirt at the end of the runway. As soon as the device could smell the dirt, the controls would turn on and let the pilot fly off the ground. In the same vein, it was suggested a bag of dirt should be carried in the front landing gear well. Upon reaching takeoff safety speed,

2052-513: A turbojet application, where the output from the gas turbine is used in a propelling nozzle, raising the turbine temperature increases the jet velocity. At normal subsonic speeds this reduces the propulsive efficiency, giving an overall loss, as reflected by the higher fuel consumption, or SFC. However, for supersonic aircraft this can be beneficial, and is part of the reason why the Concorde employed turbojets. Turbojet systems are complex systems therefore to secure optimal function of such system, there

2166-512: A turbojet engine is always subsonic, regardless of the speed of the aircraft itself. The intake has to supply air to the engine with an acceptably small variation in pressure (known as distortion) and having lost as little energy as possible on the way (known as pressure recovery). The ram pressure rise in the intake is the inlet's contribution to the propulsion system's overall pressure ratio and thermal efficiency . The intake gains prominence at high speeds when it generates more compression than

2280-494: A turbojet is high enough at higher thrust settings to cause the nozzle to choke. If, however, a convergent-divergent de Laval nozzle is fitted, the divergent (increasing flow area) section allows the gases to reach supersonic velocity within the divergent section. Additional thrust is generated by the higher resulting exhaust velocity. Thrust was most commonly increased in turbojets with water/methanol injection or afterburning . Some engines used both methods. Liquid injection

2394-487: A two-stage axial compressor feeding a single-sided centrifugal compressor . Practical axial compressors were made possible by ideas from A.A. Griffith in a seminal paper in 1926 ("An Aerodynamic Theory of Turbine Design"). Whittle later concentrated on the simpler centrifugal compressor only, for a variety of practical reasons. A Whittle engine was the first turbojet to run, the Power Jets WU , on 12 April 1937. It

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2508-497: Is a call for the newer models being developed to advance its control systems to implement the newest knowledge from the areas of automation, so increase its safety and effectiveness. Lockheed Corporation The Lockheed Corporation was an American aerospace manufacturer . Lockheed was founded in 1926 and merged in 1995 with Martin Marietta to form Lockheed Martin . Its founder, Allan Lockheed , had earlier founded

2622-413: Is a component of a turbojet used to divert air into the intake, in front of the accessory drive and to house the starter motor. An intake, or tube, is needed in front of the compressor to help direct the incoming air smoothly into the rotating compressor blades. Older engines had stationary vanes in front of the moving blades. These vanes also helped to direct the air onto the blades. The air flowing into

2736-523: Is greater than atmospheric pressure, and extra terms must be added to the above equation to account for the pressure thrust. The rate of flow of fuel entering the engine is very small compared with the rate of flow of air. If the contribution of fuel to the nozzle gross thrust is ignored, the net thrust is: F N = m ˙ a i r ( V j − V ) {\displaystyle F_{N}={\dot {m}}_{air}(V_{j}-V)} The speed of

2850-573: Is modelled approximately by the Brayton cycle . The efficiency of a gas turbine is increased by raising the overall pressure ratio, requiring higher-temperature compressor materials, and raising the turbine entry temperature, requiring better turbine materials and/or improved vane/blade cooling. It is also increased by reducing the losses as the flow progresses from the intake to the propelling nozzle. These losses are quantified by compressor and turbine efficiencies and ducting pressure losses. When used in

2964-589: Is more commonly by use of a turboshaft engine, a development of the gas turbine engine where an additional turbine is used to drive a rotating output shaft. These are common in helicopters and hovercraft. Turbojets were widely used for early supersonic fighters , up to and including many third generation fighters , with the MiG-25 being the latest turbojet-powered fighter developed. As most fighters spend little time traveling supersonically, fourth-generation fighters (as well as some late third-generation fighters like

3078-507: The DC-10 ) strongly opposed the bill and they feared the government would steer contracts to Lockheed to insure loan payments. Admiral Hyman G. Rickover condemned the bill saying it represented "a new philosophy where we privatize profits and socialize losses." The New York Times editorial board held that the Nixon administration was violating its own free enterprise principles by advocating for

3192-633: The Esquadra 91 (91st Squadron), carrying out bomb, rocket and gun attacks against separatist forces. In 1966, after Rhodesia's Unilateral Declaration of Independence , and the imposition of the Beira Patrol by the British Royal Navy to attempt to stop the flow of fuel to Rhodesia via the port of Beira, Mozambique , a detachment of eight F-84s was sent from Luanda to Mozambique to guard against potential clashes with British forces, with

3306-621: The F-111 and Hawker Siddeley Harrier ) and subsequent designs are powered by the more efficient low-bypass turbofans and use afterburners to raise exhaust speed for bursts of supersonic travel. Turbojets were used on Concorde and the longer-range versions of the Tu-144 which were required to spend a long period travelling supersonically. Turbojets are still common in medium range cruise missiles , due to their high exhaust speed, small frontal area, and relative simplicity. The first patent for using

3420-704: The Gloster Meteor , entered service in 1944, towards the end of World War II , the Me 262 in April and the Gloster Meteor in July. Only about 15 Meteor saw WW2 action but up to 1400 Me 262s were produced, with 300 entering combat, delivering the first ground attacks and air combat victories of jet planes. Air is drawn into the rotating compressor via the intake and is compressed to a higher pressure before entering

3534-588: The Heinkel HeS 3 ), or an axial compressor (as in the Junkers Jumo 004 ) which gave a smaller diameter, although longer, engine. By replacing the propeller used on piston engines with a high speed jet of exhaust, higher aircraft speeds were attainable. One of the last applications for a turbojet engine was Concorde which used the Olympus 593 engine. However, joint studies by Rolls-Royce and Snecma for

Republic F-84 Thunderjet - Misplaced Pages Continue

3648-540: The Imperial Japanese Army . At the beginning of World War II, Lockheed – under the guidance of Clarence (Kelly) Johnson , who is considered one of the best-known American aircraft designers – answered a specification for an interceptor by submitting the P-38 Lightning fighter aircraft, a twin-engined, twin-boom design. The P-38 was the only American fighter aircraft in production throughout

3762-565: The L-049 Constellation , a radical new airliner capable of flying 43 passengers between New York and London at a speed of 300 mph (480 km/h) in 13 hours. Once the Constellation (nicknamed Connie ) went into production, the military received the first production models; after the war, the airlines received their original orders, giving Lockheed more than a year's head-start over other aircraft manufacturers in what

3876-527: The North American XB-70 Valkyrie , each feeding three engines with an intake airflow of about 800 pounds per second (360 kg/s). The turbine rotates the compressor at high speed, adding energy to the airflow while squeezing (compressing) it into a smaller space. Compressing the air increases its pressure and temperature. The smaller the compressor, the faster it turns. The (large) GE90-115B fan rotates at about 2,500 RPM, while

3990-488: The Rolls-Royce Welland and Rolls-Royce Derwent , and by 1949 the de Havilland Goblin , being type tested for 500 hours without maintenance. It was not until the 1950s that superalloy technology allowed other countries to produce economically practical engines. Early German turbojets had severe limitations on the amount of running they could do due to the lack of suitable high temperature materials for

4104-424: The Tu-144 , also used afterburners as does Scaled Composites White Knight , a carrier aircraft for the experimental SpaceShipOne suborbital spacecraft. Reheat was flight-trialled in 1944 on the W.2/700 engines in a Gloster Meteor I . The net thrust F N {\displaystyle F_{N}\;} of a turbojet is given by: F N = ( m ˙

4218-545: The "Lockheed Loan". Even after its adoption, a further controversy developed when the Emergency Loan Guarantee Board set up by the Executive branch to oversee the loan refused to allow Congress' General Accounting Office to examine its records. They argued that the office was attempting "interference in the decision-making process" amounting to an effort to "bully" and "harass" the board. This claim

4332-603: The 1970s. Drowning in debt, in 1971 Lockheed (then the largest US defense contractor) asked the US government for a loan guarantee, to avoid insolvency. Lockheed argued that a government bailout was necessary due to the company's value for U.S. national security. On May 13, 1971, the Richard Nixon administration sent a bill titled "The Emergency Loan Guarantee Act" to Congress requesting a $ 250 million loan guarantee for Lockheed and its L-1011 Tristar airbus program. The measure

4446-461: The 1970s. In late 1975 and early 1976, a subcommittee of the U.S. Senate led by Senator Frank Church concluded that members of the Lockheed board had paid members of friendly governments to guarantee contracts for military aircraft. In 1976, it was publicly revealed that Lockheed had paid $ 22 million in bribes to foreign officials in the process of negotiating the sale of aircraft including

4560-549: The Constellation obsolete. However, the design proved underpowered. The company sought to purchase Convair in 1946, but the sale was blocked by the SEC . In 1943, Lockheed began, in secrecy, development of a new jet fighter at its Burbank facility. This fighter, the Lockheed P-80 Shooting Star , became the first American jet fighter to score a kill. It also recorded the first jet-to-jet aerial kill, downing

4674-799: The F-104 Starfighter, the so-called Deal of the Century. The scandal caused considerable political controversy in West Germany , the Netherlands , Italy, and Japan. In the US, the scandal led to passage of the Foreign Corrupt Practices Act , and nearly led to the ailing corporation's downfall (it was already struggling due to the poor sales of the L-1011 airliner). Haughton resigned his post as chairman. In

Republic F-84 Thunderjet - Misplaced Pages Continue

4788-467: The F-80 revealed that while the Shooting Star had a shorter takeoff roll, better low altitude climb rate and superior maneuverability, the F-84 could carry a greater bomb load, was faster, had better high altitude performance and greater range. As a compromise, the USAF in 1949 committed US$ 8 million to implement over 100 upgrades to all F-84Bs and F-84Cs, most notably reinforcing the wings to

4902-477: The F-84C was virtually identical to the F-84B, and suffered from the same defects. A 1948 review of the F-84 program discovered that none of the F-84B or F-84C aircraft could be considered operational or capable of executing any aspect of their intended mission. The program was saved from cancellation because the F-84D, whose production was well underway, had satisfactorily addressed the major faults. A fly-off against

5016-746: The F-84D and F-84E were more suitable, and so the F-84E-equipped 27th Fighter Escort Group was sent to the Far East aboard the aircraft carrier Bataan , which arrived in Japan on 30 November 1950. After maintenance, the F-84s moved to Taegu airfield (known as K-2), flying its first operational missions on 7 December 1950. The aircraft were initially tasked with escorting the B-29 Superfortress bombers. The first Thunderjet air-to-air victory

5130-681: The German side of the border and the pilot successfully ejected. Portugal received its first F-84s in January 1953, with 25 new build F-84Gs later supplemented by USAFE stocks and from other European operators, with deliveries eventually reaching 125 F-84Gs. They were the Força Aérea Portuguesa 's first operational jet fighters. Two squadrons were formed in Portugal, operating the F-84 in both air-defense and ground attack roles, with

5244-612: The Lockheed Aircraft Company to Detroit Aircraft Corporation . In August 1929, Allan Loughead resigned. The Great Depression ruined the aircraft market, and Detroit Aircraft went bankrupt. A group of investors headed by brothers Robert and Courtland Gross, and Walter Varney , bought the company out of receivership in 1932. The syndicate bought the company for a mere $ 40,000 ($ 858,000 in 2023). Ironically, Allan Loughead himself had planned to bid for his own company, but had raised only $ 50,000 ($ 824,000), which he felt

5358-765: The Poseidon and Trident nuclear missiles. Lockheed developed the F-104 Starfighter in the late 1950s, the world's first Mach 2 fighter jet. In the early 1960s, the company introduced the C-141 Starlifter four-engine jet transport. During the 1960s, Lockheed began development for two large aircraft: the C-5 Galaxy military transport and the L-1011 TriStar wide-body civil airliner. Both projects encountered delays and cost overruns. The C-5

5472-579: The Thunderjet also equipping an aerobatic display team, the Dragões . In 1960, the two operational F-84 squadrons were disbanded and the remaining F-84s transferred to training units. In 1961, however, an uprising against Portuguese rule began in Angola , and as a result, 25 F-84Gs were refurbished by OGMA and sent to Angola, with the first aircraft arriving at Luanda in August that year. There, they formed

5586-416: The Thunderjet's takeoff performance left much to be desired. In hot Korean summers with a full combat load, the aircraft routinely required 10,000 ft (3,000 m) of runway for takeoff even with the help of RATO bottles (two or four of these were carried, each producing 1,000 lbf (4.4 kN) of thrust for 14 seconds). All but the lead aircraft had their visibility obscured by the thick smoke from

5700-706: The U-2 (late 1950s), SR-71 Blackbird (1962) and F-117 Nighthawk stealth fighter (1978). The Skunk Works often created high-quality designs in a short time and sometimes with limited resources. In 1954, the Lockheed C-130 Hercules , a durable four-engined transport, flew for the first time. This type remains in production today. In 1956, Lockheed received a contract for the development of the Polaris Submarine Launched Ballistic Missile ( SLBM ); it would be followed by

5814-475: The US, and converting F-80 squadrons already in theater. The F-84 flew a total of 86,408 missions, dropping 55,586 tons (50,427  metric tons ) of bombs and 6,129 tons (5,560 metric tons) of napalm , and firing 22,154 rockets. The USAF claimed F-84s were responsible for 60% of all ground targets destroyed in the war. Notable F-84 operations included the 1952 attack on the Sui-ho Dam . During

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5928-464: The aircraft decreases the efficiency of the engine because it has been compressed, but then does not contribute to producing thrust. Compressor types used in turbojets were typically axial or centrifugal. Early turbojet compressors had low pressure ratios up to about 5:1. Aerodynamic improvements including splitting the compressor into two separately rotating parts, incorporating variable blade angles for entry guide vanes and stators, and bleeding air from

6042-1502: The aircraft returning to Angola when the threat of military action receded. Attrition of the F-84s was heavy, and by 1973, only five F-84s remained operational, with the last examples withdrawn from use that year, although the F-84G nominally remained in Portuguese service until October 1975. The Republic of China Air Force received surplus F-84Gs from the USAF from 1953, and during the Second Taiwan Strait Crisis in 1958, its F-84s engaging in air-to-air combat against People's Liberation Army Air Force MiG-15s and MiG-17 fighters, with losses on both sides. The Republic of China replaced its Thunderjets with F-100s from later that year. Notes: The costs are 1950 estimates and have not been adjusted for inflation. Data from Thunderjets in Korea General characteristics Performance Armament Related development Aircraft of comparable role, configuration, and era Turbojet Turbojets have poor efficiency at low vehicle speeds, which limits their usefulness in vehicles other than aircraft. Turbojet engines have been used in isolated cases to power vehicles other than aircraft, typically for attempts on land speed records . Where vehicles are "turbine-powered", this

6156-547: The aircraft took to the air, the USAAF placed an additional order for 25 service test YP-84As and 75 production P-84Bs (later modified to 15 YP-84A and 85 P-84B). Meanwhile, wind tunnel testing by the National Advisory Committee for Aeronautics revealed longitudinal instability and stabilizer skin buckling at high speeds. The weight of the aircraft, a great concern given the low thrust of early turbojets,

6270-1073: The aircraft's structure was not thoroughly studied. This proved problematic later. After the creation of the United States Air Force by the National Security Act of 1947 , the "Pursuit" designation was replaced with "Fighter", and the P-84 became the F-84. The F-84B, which differed from the YP-84A only in having faster-firing M3 machine guns (later F-84s also had provision to carry eight 5 in (130 mm) High Velocity Aircraft Rockets (HVAR) underwing), became operational with 14th Fighter Group at Dow Field , Bangor, Maine , in December 1947. Flight restrictions followed immediately, limiting maximum speed to Mach 0.8 due to control reversal , and limiting maximum acceleration to 5.5  g-force (54 m/s) due to wrinkling of

6384-570: The airspeed was sufficiently easy to control to make safe dive bombing from 10,000 ft possible. The top speed limitation proved troublesome against Soviet Mikoyan-Gurevich MiG-15s in Korea. Slower than the MiG, the F-84 was also unable to turn tightly with a maximum instantaneous-turn load of only 3 gs followed by rapid loss of airspeed. One F-84E pilot credited with two MiG kills achieved his second victory by intentionally flying his aircraft into pitch-up . The MiGs chasing him were unable to follow

6498-399: The combat radius from 850 mi (740 nmi; 1,370 km) to over 1,000 mi (870 nmi; 1,600 km). One improvement to the original F-84 design was rocket racks that folded flush with the wing after the 5-inch HVAR rockets were fired, which reduced drag over the older fixed mounting racks. This innovation was adopted by other US jet fighter-bombers. Despite the improvements,

6612-410: The combustion chamber. Fuel is mixed with the compressed air and burns in the combustor. The combustion products leave the combustor and expand through the turbine where power is extracted to drive the compressor. The turbine exit gases still contain considerable energy that is converted in the propelling nozzle to a high speed jet. The first turbojets, used either a centrifugal compressor (as in

6726-432: The combustor and pass through to the turbine in a continuous flowing process with no pressure build-up. Instead, a small pressure loss occurs in the combustor. The fuel-air mixture can only burn in slow-moving air, so an area of reverse flow is maintained by the fuel nozzles for the approximately stoichiometric burning in the primary zone. Further compressed air is introduced which completes the combustion process and reduces

6840-661: The company should be allowed to go into bankruptcy citing the recent decision to leave Penn Central railroad to that fate, and the fact that the airbus program at issue was commercial rather than military. Naval scholar Thomas Paul Stanton notes that the opposition to the bill held it was "the beginning of the socialization of the American aircraft and aerospace industry." Proponents responded by claiming "this socializing process had taken place many years before", and some witnesses before Congress discounted "the very notion of 'free enterprise'." Treasury Secretary Connally pointed to

6954-421: The compressor enabled later turbojets to have overall pressure ratios of 15:1 or more. After leaving the compressor, the air enters the combustion chamber. The burning process in the combustor is significantly different from that in a piston engine . In a piston engine, the burning gases are confined to a small volume, and as the fuel burns, the pressure increases. In a turbojet, the air and fuel mixture burn in

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7068-401: The compressor is passed through these to keep the metal temperature within limits. The remaining stages do not need cooling. In the first stage, the turbine is largely an impulse turbine (similar to a pelton wheel ) and rotates because of the impact of the hot gas stream. Later stages are convergent ducts that accelerate the gas. Energy is transferred into the shaft through momentum exchange in

7182-536: The compressor stage. Well-known examples are the Concorde and Lockheed SR-71 Blackbird propulsion systems where the intake and engine contributions to the total compression were 63%/8% at Mach 2 and 54%/17% at Mach 3+. Intakes have ranged from "zero-length" on the Pratt & Whitney TF33 turbofan installation in the Lockheed C-141 Starlifter , to the twin 65 feet (20 m) long, intakes on

7296-566: The entirety of American involvement in the war, from Pearl Harbor to Victory over Japan Day . It filled ground-attack, air-to-air, and even tactical bombing roles in all theaters of the war in which the United States operated. The P-38 was responsible for shooting down more Japanese aircraft than any other U.S. Army Air Forces type during the war; it is particularly famous for being the aircraft type that shot down Japanese Admiral Isoroku Yamamoto 's airplane. The Lockheed Vega factory

7410-455: The faltering economy and worries about unemployment while testifying "the time has come within the United States when we have to look at things differently. Free enterprise is just not all that free." Questions arose whether letting Lockheed fail would be bad for the market due to decreased competition or good by screening out inefficient competitors and mismanagement. Lockheed's competitors, McDonnell Douglas and General Electric (collaborators on

7524-432: The fuselage skin. To compound the problem, parts shortages and maintenance difficulties earned the aircraft the nickname, "Mechanic's Nightmare". On 24 May 1948, the entire F-84B fleet was grounded due to structural failures in the aircraft's wings. The F-84C featured a somewhat more reliable J35-A-13C engine of the same power as the A-15-C used by the F-84B, and modified fuel and electrical systems. Beyond these modifications,

7638-475: The high-temperature materials used in their turbosuperchargers during World War II. Water injection was a common method used to increase thrust, usually during takeoff, in early turbojets that were thrust-limited by their allowable turbine entry temperature. The water increased thrust at the temperature limit, but prevented complete combustion, often leaving a very visible smoke trail. Allowable turbine entry temperatures have increased steadily over time both with

7752-444: The in-service rates for the F-84E remained poor with only half of the aircraft operational in April 1950. This was primarily due to a severe shortage of spares for the Allison engines. The expectation was that F-84Es would fly 25 hours per month, accumulating 100 hours between engine overhauls. The actual flight hours for Korean War and NATO deployments rapidly outpaced the supply and Allison's ability to manufacture new engines. The F-84E

7866-441: The introduction of superior alloys and coatings, and with the introduction and progressive effectiveness of blade cooling designs. On early engines, the turbine temperature limit had to be monitored, and avoided, by the pilot, typically during starting and at maximum thrust settings. Automatic temperature limiting was introduced to reduce pilot workload and reduce the likelihood of turbine damage due to over-temperature. A nose bullet

7980-401: The jet V j {\displaystyle V_{j}\;} must exceed the true airspeed of the aircraft V {\displaystyle V\;} if there is to be a net forward thrust on the airframe. The speed V j {\displaystyle V_{j}\;} can be calculated thermodynamically based on adiabatic expansion . The operation of a turbojet

8094-401: The late 1980s, leveraged buyout specialist Harold Simmons conducted a widely publicized but unsuccessful takeover attempt on the Lockheed Corporation, having gradually acquired almost 20 percent of its stock. Lockheed was attractive to Simmons because one of its primary investors was the California Public Employees' Retirement System (CalPERS), the pension fund of the state of California. At

8208-407: The loan. (Later, historian Stephen J. Whitfield viewed the passage of the loan guarantee as a support for the argument that America was shifting away from Lockean liberalism. ) Following a fierce debate, Vice President Spiro T. Agnew cast a tie-breaking vote in favor of the measure on August 2, 1971. President Nixon signed the bill into law on August 9, 1971 - which became colloquially known as

8322-698: The new XP-84—known to Republic as the Model AP-23. Since the design promised superior performance to the Lockheed -built P-80 Shooting Star and Republic had extensive experience in building single-seat fighters, no competition was held for the contract. The name "Thunderjet" was chosen to continue the Republic Aviation tradition started with the P-47 Thunderbolt, while emphasizing the new method of propulsion. On 4 January 1945, even before

8436-583: The new aircraft had to use the General Electric TG-180 axial turbojet which entered production as the Allison J35 . These specifications proved to be too ambitious, however, and the radius requirement was reduced to 705 mi (613 nmi; 1,135 km) and the armament suite was reduced to six .50-caliber or four .60-caliber machine guns in order to reduce weight. On 11 November 1944, Republic received an order for three prototypes of

8550-464: The nose and one in each wing root), and having the provision for wingtip fuel tanks holding 226  US gal (188  imp gal ; 860  L ) each. Due to delays with delivery of jet engines and production of the XP-84A, the Thunderjet had undergone only limited flight testing by the time production P-84Bs began to roll out of the factory in 1947. In particular, the impact of wingtip tanks on

8664-554: The nose of the fuselage, with air ducts running from the nose to the engine and taking up much of the fuselage volume. Fuel was mainly stored in tanks in the thick, but laminar flow airfoil, unswept wings. On 11 September 1944, the USAAF released General Operational Requirements for a day fighter with a top speed of 600 mph (520  kn ; 970  km/h ), a combat radius of 850 mi (740  nmi ; 1,370  km ), and armament of either eight .50 in (12.7 mm) or six .60 in (15.2 mm) machine guns. In addition,

8778-402: The opposite way to energy transfer in the compressor. The power developed by the turbine drives the compressor and accessories, like fuel, oil, and hydraulic pumps that are driven by the accessory gearbox. After the turbine, the gases expand through the exhaust nozzle producing a high velocity jet. In a convergent nozzle, the ducting narrows progressively to a throat. The nozzle pressure ratio on

8892-654: The pilot would dump the dirt under the wheels, fooling the sniffer device. The Thunderjet had a distinguished record during the Korean War . After the entry of the People's Republic of China into the war in October 1950, the US Fifth Air Force requested that a wing of F-84s be sent to Korea. While the F-84B and F-84C could not be deployed overseas because their J35 engines had a service life of only 40 hours,

9006-467: The program. The aircraft was not considered fully operational until the 1949 F-84D model and the design matured only with the definitive F-84G introduced in 1951. In 1954, the straight-wing Thunderjet was joined by the swept-wing F-84F Thunderstreak fighter and RF-84F Thunderflash photo reconnaissance aircraft . The Thunderjet became the USAF's primary strike aircraft during the Korean War , flying 86,408 sorties and destroying 60% of all ground targets in

9120-410: The ramifications of the Lockheed loan guarantee soon resurfaced in late 1975 with discussions on possible aid to New York City during its fiscal crisis . Lockheed finished paying off the $ 1.4 billion loan in 1977, along with about $ 112.22 million in loan guarantee fees. The Lockheed bribery scandals were a series of illegal bribes and contributions made by Lockheed officials from the late 1950s to

9234-496: The rockets. F-84s had to be pulled off the ground at 160 mph (140 kn, 260 km/h) with the control stick held all the way back. Landings were made at a similar speed. For comparison, the North American P-51 Mustang landed at approximately 120 mph (100 kn, 190 km/h). Despite the "hot" landing speeds, the Thunderjet was easy to fly on instruments and crosswinds did not present much of

9348-535: The same technology originally developed for the Model S-1 to design the Vega Model . In March 1928, the company relocated to Burbank, California , and by year's end reported sales exceeding one million dollars. From 1926 to 1928 the company produced over 80 aircraft and employed more than 300 workers who by April 1929 were building five aircraft per week. In July 1929, majority shareholder Fred Keeler sold 87% of

9462-483: The similarly named but otherwise-unrelated Loughead Aircraft Manufacturing Company , which was operational from 1912 to 1920. Allan Loughead and his brother Malcolm Loughead had operated an earlier aircraft company, Loughead Aircraft Manufacturing Company , which was operational from 1912 to 1920. The company built and operated aircraft for paying passengers on sightseeing tours in California and had developed

9576-468: The supersonic airliner, in terms of miles per gallon, compared to subsonic airliners at Mach 0.85 (Boeing 707, DC-8) was relatively small. This is because the large increase in drag is largely compensated by an increase in powerplant efficiency (the engine efficiency is increased by the ram pressure rise which adds to the compressor pressure rise, the higher aircraft speed approaches the exhaust jet speed increasing propulsive efficiency). Turbojet engines had

9690-521: The takeover since he was also at the time pursuing control of Georgia Gulf . Merger talks between Lockheed and Martin Marietta began in March 1994, with the companies announcing their $ 10 billion planned merger on August 30, 1994. The headquarters for the combined companies would be at Martin Marietta headquarters in North Bethesda, Maryland . The deal was finalized on March 15, 1995, when

9804-446: The temperature of the combustion products to a level which the turbine can accept. Less than 25% of the air is typically used for combustion, as an overall lean mixture is required to keep within the turbine temperature limits. Hot gases leaving the combustor expand through the turbine. Typical materials for turbines include inconel and Nimonic . The hottest turbine vanes and blades in an engine have internal cooling passages. Air from

9918-548: The thrust from a turbojet engine. It was flown by test pilot Erich Warsitz . The Gloster E.28/39 , (also referred to as the "Gloster Whittle", "Gloster Pioneer", or "Gloster G.40") made the first British jet-engined flight in 1941. It was designed to test the Whittle jet engine in flight, and led to the development of the Gloster Meteor. The first two operational turbojet aircraft, the Messerschmitt Me 262 and then

10032-465: The time, the New York Times said, "Much of Mr. Simmons's interest in Lockheed is believed to stem from its pension plan, which is over funded by more than $ 1.4 billion. Analysts said he might want to liquidate the plan and pay out the excess funds to shareholders, including himself." Citing the mismanagement by its chairman, Daniel M. Tellep , Simmons stated a wish to replace its board with

10146-412: The turbines would overheat, the lubricating oil would leak from the bearing cavities, the rotor thrust bearings would skid or be overloaded, and ice would form on the nose cone. The air from the compressor, called secondary air, is used for turbine cooling, bearing cavity sealing, anti-icing, and ensuring that the rotor axial load on its thrust bearing will not wear it out prematurely. Supplying bleed air to

10260-408: The turbines. British engines such as the Rolls-Royce Welland used better materials giving improved durability. The Welland was type-certified for 80 hours initially, later extended to 150 hours between overhauls, as a result of an extended 500-hour run being achieved in tests. General Electric in the United States was in a good position to enter the jet engine business due to its experience with

10374-500: The two companies' shareholders approved the merger. The segments of the two companies not retained by the new company formed the basis for L-3 Communications , a mid-size defense contractor in its own right. Lockheed Martin also later spun off the materials company Martin Marietta Materials . The company's executives received large bonuses directly from the government as a result of the merger. Norman R. Augustine who

10488-581: The violent maneuver and one crashed into the ground. Luckily for the F-84E pilot, the aircraft did not disintegrate but the airframe did suffer heavy warping. The F-84 was a stable gun platform and the computing gunsight aided in accurate gunnery and bombing. Pilots praised the aircraft for Republic's legendary ruggedness. Pilots nicknamed the Thunderjet "The Lead Sled". It was also called "The Iron Crowbar", "a hole sucking air", "The Hog" ("The Groundhog"), and "The World's Fastest Tricycle", "Ground Loving Whore" as

10602-433: The war as well as eight Soviet-built MiG fighters . Over half of the 7,524 F-84s produced served with NATO nations, and it was the first aircraft to fly with the U.S. Air Force Thunderbirds demonstration team. The USAF Strategic Air Command had F-84 Thunderjets in service from 1948 through 1957. The F-84 was the first production fighter aircraft to utilize inflight refueling and the first fighter capable of carrying

10716-762: The war, the F-84 became the first USAF fighter to utilize aerial refueling . In aerial combat, F-84 pilots were credited with eight MiG-15 kills against a Soviet-claimed loss of 64 aircraft. The total losses were 335 F-84D, E and G models. According to the USAF FY1953 statistical digest, during the Korean war, 305 F-84s were lost, including 249 in combat missions and 56 non-combat losses. Air battle over Merklín - A notable incident occurred on 10 March 1953, when two Czech MiG 15 fighters intercepted two US Air Force F-84Es that were claimed to have strayed from German to Czechoslovakian airspace and shot one down. It crashed on

10830-664: The world in 1937. Subsequent designs, the Lockheed Model 12 Electra Junior and the Lockheed Model 14 Super Electra expanded their market. The Lockheed Model 14 formed the basis for the Hudson bomber, which was supplied to both the British Royal Air Force and the United States military before and during World War II . Its primary role was submarine hunting. The Model 14 Super Electra were sold abroad, and more than 100 were license-built in Japan for use by

10944-534: The world speed record of 612.2 mph (532.0 kn; 985.2 km/h) set the day before by a British Gloster Meteor . The effort to break the speed record delayed the test program with the second prototype. The 15 YP-84As, which were delivered to Patterson Field (present-day Wright-Patterson Air Force Base ) for service tests from January 1947, differed from XP-84s by having an upgraded J35-A-15 engine, carrying six 0.50 in M2 Browning machine guns (four in

11058-456: Was an experimental turboprop version of the F-84F. The F-84F swept wing version was intended to be a small variation of the normal Thunderjet with only a few different parts, so it kept the basic F-84 number. Production delays on the F-84F resulted in another order of the straight-wing version; this was the F-84G. In 1944, Republic Aviation 's chief designer, Alexander Kartveli , began working on

11172-695: Was at the time CEO of Martin Marietta received an $ 8.2 million bonus. Both companies contributed important products to the new portfolio. Lockheed products included the Trident missile , P-3 Orion maritime patrol aircraft , U-2 and SR-71 reconnaissance airplanes , F-117 Nighthawk , F-16 Fighting Falcon , F-22 Raptor , C-130 Hercules , A-4AR Fightinghawk and the DSCS-3 satellite. Martin Marietta products included Titan rockets , Sandia National Laboratories (management contract acquired in 1993), Space Shuttle External Tank , Viking 1 and Viking 2 landers,

11286-593: Was built in any number (141 aircraft) was the Vega first built in 1927, best known for its several first- and record-setting flights by, among others, Amelia Earhart , Wiley Post , and George Hubert Wilkins . In the 1930s, Lockheed spent $ 139,400 ($ 2.29 million) to develop the Model 10 Electra , a small twin-engined transport. The company sold 40 in the first year of production. Amelia Earhart and her navigator, Fred Noonan , flew it in their failed attempt to circumnavigate

11400-718: Was built to vague initial requirements and suffered from structural weaknesses, which Lockheed was forced to correct at its own expense. The TriStar competed for the same market as the McDonnell Douglas DC-10 ; delays in Rolls-Royce engine development caused the TriStar to fall behind the DC-10. The C-5 and L-1011 projects, the canceled U.S. Army AH-56 Cheyenne helicopter program, and embroiled shipbuilding contracts caused Lockheed to lose large sums of money during

11514-433: Was denied by Comptroller General Elmer B. Staats , and efforts were made by Senator William Proxmire to get Treasury Secretary John Connally to testify due to the suspicion that the loan guarantee was in jeopardy. The editorial board of The New York Times blasted the situation, citing it as another argument against the propriety of the loan guarantee and the precedent it set for other failing companies. The debate around

11628-400: Was easily foreseen as the post-war modernization of civilian air travel. The Constellation's performance set new standards which transformed the civilian transportation market. Its signature tri-tail was the result of many initial customers not having hangars tall enough for a conventional tail. Lockheed produced a larger transport, the double-decked R6V Constitution , which was intended to make

11742-399: Was fitted. It had been discovered that the untested wingtip fuel tanks contributed to wing structural failures by inducing excessive twisting during high-g maneuvers. To correct this, small triangular fins were added to the outside of the tanks. The F-84D was phased out of USAF service in 1952 and left Air National Guard (ANG) service in 1957. The first effective and fully capable Thunderjet

11856-463: Was growing so quickly that the USAAF had to set a gross weight limit of 13,400  lb (6,100  kg ). The results of this preliminary testing were incorporated into the third prototype, designated XP-84A , which was also fitted with a more powerful J35-GE-15 engine with 4,000 lbf (17.79 kN) of thrust. The first prototype XP-84 was rolled out in December 1945, but availability of suitable engines delayed flight testing. The first prototype

11970-518: Was hotly debated in the US Senate. The chief antagonist was Senator William Proxmire (D-Wis), the nemesis of Lockheed and its chairman, Daniel J. Haughton. Some of the debate in Congress developed over what conditions should be attached to the bailout. Senator Alan Cranston demanded that the management be forced to step down, lest it set a precedent rewarding wasteful spending. Others argued that

12084-424: Was liquid-fuelled. Whittle's team experienced near-panic during the first start attempts when the engine accelerated out of control to a relatively high speed despite the fuel supply being cut off. It was subsequently found that fuel had leaked into the combustion chamber during pre-start motoring checks and accumulated in pools, so the engine would not stop accelerating until all the leaked fuel had burned off. Whittle

12198-538: Was located next to Burbank's Union Airport which it had purchased in 1940. During the war, the entire area was camouflaged in case of enemy reconnaissance. The factory was hidden beneath a huge burlap tarpaulin painted to depict a peaceful semi-rural neighborhood, replete with rubber automobiles. Hundreds of fake trees, shrubs, buildings, and even fire hydrants were positioned to give a three-dimensional appearance. The trees and shrubs were created from chicken wire treated with an adhesive and covered with feathers to provide

12312-494: Was scored on 21 January 1951 at the cost of two F-84s. The F-84 was outmatched by the swept-wing Soviet Mikoyan-Gurevich MiG-15 , which was both faster and more manoeuvrable, and the MiG counter-air mission was soon given to the F-86 Sabre . The F-84 switched to the ground attack role at which it excelled. The number of units operating the F-84 over Korea gradually increased, both by bringing over Air National Guard Groups from

12426-640: Was tested on the Power Jets W.1 in 1941 initially using ammonia before changing to water and then water-methanol. A system to trial the technique in the Gloster E.28/39 was devised but never fitted. An afterburner or "reheat jetpipe" is a combustion chamber added to reheat the turbine exhaust gases. The fuel consumption is very high, typically four times that of the main engine. Afterburners are used almost exclusively on supersonic aircraft , most being military aircraft. Two supersonic airliners, Concorde and

12540-563: Was the F-84E model which entered service in 1950. The aircraft featured the J35-A-17 engine, further wing reinforcement, a 12 in (300 mm) fuselage extension in front of the wings and 3 in (76 mm) extension aft of the wings to enlarge the cockpit and the avionics bay, an A-1B gunsight with AN/APG-30 range-finding radar, and provision for an additional pair of 230 US gal (190 imp gal; 870 L) fuel tanks to be carried on underwing pylons. The latter increased

12654-654: Was too small a sum for a serious bid. In 1934, Robert E. Gross was named chairman of the new company, the Lockheed Aircraft Corporation, which was headquartered at what is now the airport in Burbank, California . His brother Courtlandt S. Gross was a co-founder and executive, succeeding Robert as chairman following his death in 1961. The company was named the Lockheed Corporation in 1977. The first successful construction that

12768-461: Was transferred to Muroc Army Air Field (present-day Edwards Air Force Base ) where it flew for the first time on 28 February 1946 with Major Wallace A. "Wally" Lien at the controls. It was joined by the second prototype in August, both aircraft flying with J35-GE-7 engines producing 3,750 lbf (16.68 kN). On 8 September 1946, the second XP-84 set a US national airspeed record of 607.2 mph (527.6 kn; 977.2 km/h), but failed to match

12882-485: Was unable to interest the government in his invention, and development continued at a slow pace. In Germany, Hans von Ohain patented a similar engine in 1935. His design, an axial-flow engine, as opposed to Whittle's centrifugal flow engine, was eventually adopted by most manufacturers by the 1950s. On 27 August 1939 the Heinkel He 178 , powered by von Ohain's design, became the world's first aircraft to fly using

12996-534: Was withdrawn from USAF service in 1956, serving with the Air Force Reserve until 1957 and lingering with ANG units until 1959. The final straight-wing F-84 was the F-84G, intended as a stop-gap until the swept wing F-84F entered service, but ordered in large numbers to build-up NATO air forces. It introduced a refueling boom receptacle in the left wing, autopilot , Instrument Landing System , J35-A-29 engine with 5,560 lbf (24.73 kN) of thrust,

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