Misplaced Pages

#772227

56-524: In 1958, the Douglas Aircraft Company proposed a short-range, four-engined jet airliner to fill the gap below its new DC-8 intercontinental, known internally as the Model 2067 . Intended to be marketed as DC-9, it was not directly related to the later twin-engined Douglas DC-9 . Pratt & Whitney (P&W) had offered its JT8A turbojet for the airliner, but Douglas preferred to go with

112-488: A McDonnell Douglas DC-9 stuck in the dirt a few feet off the runway 's edge. The first officer on the TWA aircraft heard a loud bang, now known to have been a compressor stall induced by ingestion of exhaust from Delta 379 as it was passed. Believing a collision had occurred, the copilot aborted the takeoff. Because of its speed, the aircraft overran the runway, injuring 11 of the 29 passengers, one of whom died four days later as

168-573: A globe. This logo was later adopted by McDonnell Douglas in 1967, and became the basis of Boeing 's current logo after their merger in 1997. Douglas Aircraft designed and built a wide variety of aircraft for the U.S. military, including the Navy, Army Air Forces, Marine Corps, Air Force, and Coast Guard. The company initially built torpedo bombers for the U.S. Navy, but it developed a number of different versions of these aircraft, including reconnaissance planes and airmail aircraft. Within five years,

224-638: A government-owned factory in Marietta, Georgia . World War II was a major boost for Douglas. Douglas ranked fifth among United States corporations in the value of wartime production contracts. The company produced almost 30,000 aircraft from 1942 to 1945, and its workforce swelled to 160,000. The company produced a number of aircraft including the C-47 Skytrain, the DB-7 (known as the A-20, Havoc or Boston),

280-438: A known deficiency of this type of engine. The 1977 loss of Southern Airways Flight 242 , a McDonnell Douglas DC-9-9-31 , while penetrating a thunderstorm cell over Georgia , was attributed to compressor stalls brought on by ingestion of large quantities of water and hail . The stalls caused blades to clash with stationary vanes in both of its Pratt & Whitney JT8D-9 turbofan engines. The stalls were so severe as to cause

336-432: A major incident occurred when a compressor surge caused a structural failure in the intake. The hammershock which propagated forward from the compressor was of sufficient strength to cause an inlet ramp to become detached and expelled from the front of the intake. The ramp mechanism was strengthened and control laws changed to prevent a re-occurrence. A compressor stall contributed to the 1994 death of Lt. Kara Hultgreen ,

392-669: A momentary power drop barely registered by the engine instruments to a complete loss of compression in case of a surge, requiring adjustments in the fuel flow to recover normal operation. Compressor stalls were a common problem on early jet engines with simple aerodynamics and manual or mechanical fuel control units , but they have been virtually eliminated by better design and the use of hydromechanical and electronic control systems such as full authority digital engine control . Modern compressors are carefully designed and controlled to avoid or limit stall within an engine's operating range. There are two types of compressor stall: Rotating stall

448-426: A result of the incidence spike, thus causing stall cell "rotation" around the rotor. Stable local stalls can also occur which are axi-symmetric, covering the complete circumference of the compressor disc, but only a portion of its radial plane, with the remainder of the face of the compressor continuing to pass normal flow. A rotational stall may be momentary, resulting from an external disturbance, or may be steady as

504-422: A result of the injuries. In December 1991 Scandinavian Airlines Flight 751 , a McDonnell Douglas MD-81 on a flight from Stockholm to Copenhagen, crashed after losing both engines due to ice ingestion leading to compressor stall shortly after takeoff. Due to a newly installed auto-throttle system designed to prevent pilots reducing power during the takeoff climb, the pilot's commands to reduce power on recognising

560-401: A stable manner up to a certain pressure ratio. Beyond this value the flow will break down and become unstable. This occurs at what is known as the surge line on a compressor map . The complete engine is designed to keep the compressor operating a small distance below the surge pressure ratio on what is known as the operating line on a compressor map. The distance between the two lines is known as

616-633: A turbofan engine, which would have a greater fuel efficiency than a turbojet. P&W then proposed the JT10A, a half-scale version of its newly developed JT8D turbofan. Development of the new design began in April 1959, using the core of the JT8. Douglas shelved the model 2067 design in 1960, as the targeted US airlines preferred the newly offered Boeing 727 . In 1960, the United States Navy selected

SECTION 10

#1732772820773

672-529: A wholly owned subsidiary of McDonnell Douglas, with Douglas' son, Donald Wills Douglas Jr. , as president. Later, former McDonnell president David S. Lewis became chairman of Douglas Aircraft. His successful turnaround of the division allowed him to become president of McDonnell Douglas in 1969. Meanwhile, Douglas' space and missiles division became part of a new subsidiary called McDonnell Douglas Astronautics Company. McDonnell Douglas later merged with its rival Boeing in 1997. Boeing merged Douglas Aircraft into

728-413: Is a compressor bleed system that automatically dumps away unwanted air to prevent compressor stalling. Other methods of stall prevention may include an anti-stall tip treatment of the casing. The Rolls-Royce Avon turbojet engine was affected by repeated compressor surges early in its 1940s development which proved difficult to eliminate from the design. Such was the perceived importance and urgency of

784-410: Is a local disruption of airflow within the compressor which continues to provide compressed air, but with reduced effectiveness. Rotating stall arises when a small proportion of airfoils experience airfoil stall , disrupting the local airflow without destabilising the compressor. The stalled airfoils create pockets of relatively stagnant air (referred to as stall cells ) which, rather than moving in

840-834: The Allison Engine Company offered to the Air Force its TF41 turbofan, a license-built version of the RB.168-25R Spey . The USAF selected the more powerful TF41 for the A-7D, as did the USN, for its similar A-7E. The Grumman F-14 Tomcat with the TF30-P-414A was underpowered, because it was the Navy's intent to procure a jet fighter with a thrust-to-weight ratio (in clean configuration) of 1 or better (the US Air Force had

896-852: The Boeing Commercial Airplanes division, and retired the Douglas Aircraft name after 76 years. The last Long Beach -built commercial aircraft, the Boeing 717 (third generation version of the Douglas DC-9), ceased production in May 2006. By 2011, the Boeing C-17 Globemaster III was the last aircraft being assembled at the Long Beach facility; the final C-17 was assembled in late 2015. However,

952-478: The Douglas DC-2 , followed by the famous DC-3 in 1936. The wide range of aircraft produced by Douglas included airliners , light and medium bombers , fighter aircraft , transports, reconnaissance aircraft, and experimental aircraft. The company is most famous for the "DC" (Douglas Commercial) series of commercial aircraft, including what is often regarded as the most significant transport aircraft ever made:

1008-779: The Douglas DC-3 , which was also produced as a military transport known as the C-47 Skytrain or "Dakota" in British service. Many Douglas aircraft have long service lives. During World War II , Douglas joined the BVD ( Boeing - Vega -Douglas) consortium to produce the B-17 Flying Fortress . After the war, Douglas built another Boeing design under license, the B-47 Stratojet turbojet -powered bomber, using

1064-610: The SBD Dauntless dive bomber , and the A-26 Invader . Douglas Aircraft suffered cutbacks at the end of the war, with an end to government aircraft orders and a surplus of aircraft. It was necessary to cut heavily into its workforce, letting go of nearly 100,000 workers. The United States Army Air Forces established 'Project RAND' (Research ANd Development) with the objective of looking into long-range planning of future weapons. In March 1946, Douglas Aircraft Company

1120-625: The U.S. Navy . The DTs were taken from the assembly lines at the company's manufacturing plants in Rock Island, Illinois , and Dayton, Ohio , to be modified. The modified aircraft known as the Douglas World Cruiser (DWC), also was the first major project for Jack Northrop who designed the fuel system for the series. After the prototype was delivered in November 1923, upon the successful completion of tests on 19 November,

1176-620: The 1950s. Douglas moved from producing air-to-air rockets and missiles to entire missile systems under the 1956 Nike missile program and became the main contractor for the Skybolt air-launched ballistic missile program and the Thor ballistic missile program. Douglas also earned contracts from NASA, most notably for designing the S-IVB stage of the Saturn IB and Saturn V rockets. In 1967,

SECTION 20

#1732772820773

1232-652: The Army commissioned Douglas to build four production series aircraft. Due to the demanding expedition ahead, spare parts, including 15 extra Liberty L-12 engines, 14 extra sets of pontoons, and enough replacement airframe parts for two more aircraft were chosen. These were sent to airports along the route. The last of these aircraft was delivered to the U.S. Army on March 11, 1924. The four aircraft left Seattle , Washington, on April 6, 1924, flying west, and two of these returned there on 28 September to great acclaim, while one plane had been lost under fog conditions, and another

1288-652: The Davis-Douglas Company. An early claim to fame was the first circumnavigation of the world by air in Douglas airplanes in 1924. In 1923, the U.S. Army Air Service was interested in carrying out a mission to circumnavigate the Earth for the first time by aircraft , a program called "World Flight". Donald Douglas proposed a modified Douglas DT to meet the Army's needs. The two-place, open cockpit DT biplane torpedo bomber had previously been produced for

1344-401: The Douglas' former logo is preserved on the facility though no longer used by Boeing. 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 the phenomenon ranges from

1400-732: The F-111 is a larger and less-maneuverable aircraft. Though the F-14A entered service with the Navy powered by the Pratt & Whitney TF30, by the end of the decade, following numerous problems with the original engine, the Department of Defense began procuring General Electric F110-GE-400 engines and installed them in the F-14A Plus (later redesignated to F-14B in 1991), which entered service with

1456-632: The F-111F had the TF30-P-100. RAAF F-111Cs were upgraded with the unique P-108 version, using a P-109 engine mated to a P-107 afterburner. The F-111 Engine Business Unit (later taken over by TAE) at RAAF Base Amberley became the world experts on the TF-30 in the years after the USAF retired their fleet and achieved extraordinary increases reliability of the TF-30. The TF30 proved itself to be well-suited to

1512-641: The JT10A, designated TF30-P-1, to power the proposed Douglas F6D Missileer , but the project was canceled in April 1961. Meanwhile, the TF30 had been chosen by General Dynamics for its entrant in the TFX competition for the United States Air Force and USN, which was selected for production as the F-111 . The version of the TF30 for the F-111 included an afterburner. The F-111A, EF-111A and F-111E used

1568-702: The TF30-P-3 turbofan. The F-111 had problems with inlet compatibility, and many faulted the placement of the intakes behind the disturbed air of the wing. Newer F-111 variants incorporated improved intake designs and most variants featured more powerful versions of the TF30 engine. The F-111E was updated to use TF30-P-103 engines, the F-111D included the TF30-P-9/109, the FB-111A used the TF-30-P-7/107, and

1624-772: The Tomcat into an upright or inverted spin, from which recovery was very difficult. The F-14's problems did not afflict TF30 engines in the USAF and RAAF F-111s to nearly the same extent. The F-111, while technically designated as a "fighter," was actually used as a ground attack aircraft and tactical bomber. A typical ground strike mission is characterized by less abrupt changes in throttle, angle of attack and altitude than an air-to-air combat mission. While it can still involve hard and violent maneuvers to avoid enemy missiles and aircraft, these maneuvers are generally still not nearly as hard and violent as those required in air-to-air combat, and

1680-489: The company was building about 100 aircraft annually. Among the early employees at Douglas were Ed Heinemann , "Dutch" Kindelberger , Carl Cover , and Jack Northrop , who later founded the Northrop Corporation . The company retained its military market and expanded into amphibian airplanes in the late 1920s, also moving its facilities to Clover Field at Santa Monica, California . The Santa Monica complex

1736-569: The company was struggling to expand production to meet demand for DC-8 and DC-9 airliners and the A-4 Skyhawk military attack aircraft. The company was also struggling with quality and cash flow problems and DC-10 development costs, as well as shortages due to the Vietnam War . Under the circumstances, Douglas was very receptive to an offer from McDonnell Aircraft Corporation . On April 28, 1967, after almost four years of merger talks,

Pratt & Whitney TF30 - Misplaced Pages Continue

1792-442: The compressor finds a working equilibrium between stalled and unstalled areas. Local stalls substantially reduce the efficiency of the compressor and increase the structural loads on the airfoils encountering stall cells in the region affected. In many cases however, the compressor airfoils are critically loaded without capacity to absorb the disturbance to normal airflow such that the original stall cells affect neighbouring regions and

1848-518: The conditions that induced the stall remain, the return of stable airflow will reproduce the conditions at the time of surge and the process will repeat. Such a "locked-in" or self-reproducing stall is particularly dangerous, with very high levels of vibration causing accelerated engine wear and possible damage, even the total destruction of the engine through the breaking of compressor and stator vanes and their subsequent ingestion, destroying engine components downstream. A compressor will only pump air in

1904-480: The destruction of the engines, leaving the flight crew with no choice but to make an emergency landing on a public road, killing 62 passengers and another eight people on the ground. On December 6, 1997, an Antonov 124 transport plane was destroyed when it crashed immediately after takeoff from Irkutsk-2 Airport in Russia. Three seconds after lifting off from Runway 14, at a height of about 5 metres (16 ft),

1960-638: The engine that Rolls-Royce licensed the compressor design of the Sapphire engine from Armstrong Siddeley to speed development. The engine, as redesigned, went on to power aircraft such as the English Electric Lightning fighter, English Electric Canberra bomber, and the de Havilland Comet and Sud Aviation Caravelle airliners. During the 1960s development of the Concorde Supersonic Transport (SST)

2016-409: The engine. Reports of jets of flame emanating from the engine are common during this type of compressor stall. These stalls may be accompanied by an increased exhaust gas temperature, an increase in rotor speed due to the large reduction in work done by the stalled compressor and – in the case of multi-engine aircraft – yawing in the direction of the affected engine due to

2072-400: The first female carrier-based United States Navy fighter pilot . Her aircraft, a Grumman F-14 Tomcat , experienced a compressor stall and failure of its left engine, a Pratt & Whitney TF30 turbofan , due to disturbed airflow caused by Hultgreen's attempt to recover from an incorrect final approach position by executing a sideslip ; compressor stalls from excessive yaw angle were

2128-508: The fleet in 1988. These engines solved the reliability problems and provided nearly 30% more thrust, achieving a 1:1 dry thrust to weight ratio with a low fuel load. The subsequent F-14D, a combination of both remanufactured/upgraded F-14As and new manufacture F-14Ds, also used F110-GE-400 engines. Source: Source: Data from The Engines of Pratt & Whitney: A Technical History. Comparable engines Related lists Douglas Aircraft Company The Douglas Aircraft Company

2184-405: The flow direction, rotate around the circumference of the compressor. The stall cells rotate with the rotor blades, but at 50 to 70% of their speed, affecting subsequent airfoils around the rotor as each encounters the stall cell. Propagation of the instability around the flow path annulus is driven by stall cell blockage causing an incidence spike on the adjacent blade. The adjacent blade stalls as

2240-405: The improved A-7B and A-7C. In 1965, the USAF selected the A-7D as a replacement for its fast-jet F-100 and F-105 supersonic fighter-bombers in the close air support role. Though the USAF had wanted the TF30, Pratt & Whitney was unable to meet the production timetable, because its facilities were already committed to producing other engines. Instead of producing the TF30 under license for P&W,

2296-418: The limit of its pressure rise capabilities or is highly loaded such that it does not have the capacity to absorb a momentary disturbance, creating a rotational stall which can propagate in less than a second to include the entire compressor. The compressor will recover to normal flow once the engine pressure ratio reduces to a level at which the compressor is capable of sustaining stable airflow. If, however,

Pratt & Whitney TF30 - Misplaced Pages Continue

2352-431: The loss of thrust. The appropriate response to compressor stalls varies according to the engine type and situation, but usually consists of immediately and steadily decreasing thrust on the affected engine. While modern engines with advanced control units can avoid many causes of stall, jet aircraft pilots must continue to take this into account when dropping airspeed or increasing throttle. A compressor anti-stall system

2408-472: The more "jet age" style F4D Skyray in 1951. Douglas also made commercial jets, producing the Douglas DC-8 in 1958 to compete with the new Boeing 707 . Douglas was a pioneer in related fields, such as ejection seats , air-to-air missiles , surface-to-air missiles , and air-to-surface missiles , launch rockets, bombs, and bomb racks. The company was ready to enter the new missile business during

2464-626: The motto "First Around the World – First the World Around". Douglas initially used a logo that combined two letter Ds with two wings extended outwards, and two Ds placed back to back to form a heart as a reference to the Clan Douglas . After the success of the DWC, the company adopted a logo that showed three airplanes circling a globe. The logo eventually evolved into an aircraft, a missile, and

2520-461: The number 3 engine surged. Climbing away with a high angle of attack , engines 1 and 2 also surged, causing the aircraft to crash some 1,600 metres (5,200 ft) past the end of the runway. It struck several houses in a residential area, killing all 23 on board, and 45 people on the ground. On November 6, 1967, TWA Flight 159 , a Boeing 707 on its takeoff roll from the then-named Greater Cincinnati Airport , passed Delta Air Lines Flight 379,

2576-528: The requirements of a high-speed low-altitude strike aircraft with a relatively long operational range, and F-111s in all guises would continue to use TF30s until their retirement. In 1964, the subsonic LTV A-7A Corsair II won the US Navy's VAL competition for a light attack aircraft to replace the Douglas A-4 Skyhawk . The A-7A used a non-afterburning variant of the TF30, which would also power

2632-566: The same goals for the F-15 Eagle and F-16 Fighting Falcon ). However, due to reliability issues with the intended Pratt & Whitney F401 engines and the intent to incorporate as many of the systems of the failed Navy version of the F-111, the F-111B , into the project, it was deemed that the initial production run of F-14s utilize the F-111B's powerplant. The F-14A's thrust-to-weight ratio

2688-477: The stalled region rapidly grows to become a complete compressor stall. Axi-symmetric stall , more commonly known as compressor surge ; or pressure surge , is a complete breakdown in compression resulting in a reversal of flow and the violent expulsion of previously compressed air out through the engine intake, due to the compressor's inability to continue working against the already-compressed air behind it. The compressor either experiences conditions which exceed

2744-550: The surge margin on a compressor map. Various things can occur during the operation of the engine to lower the surge pressure ratio or raise the operating pressure ratio. When the two coincide there is no longer any surge margin and a compressor stage can stall or the complete compressor can surge as explained in preceding sections. The following, if severe enough, can cause stalling or surging. Compressor axially-symmetric stalls, or compressor surges, are immediately identifiable, because they produce one or more extremely loud bangs from

2800-403: The two companies merged as McDonnell Douglas Corporation . The two companies seemed to be a good match for each other. McDonnell was a major defense contractor, but had almost no civilian business. Douglas' commercial contracts would allow McDonnell to withstand any downturns in procurement. Conversely, McDonnell had enough revenue to help solve Douglas' financial problems; soon after the merger

2856-630: Was an American aerospace and defense company based in Southern California . Founded in 1921 by Donald Wills Douglas Sr. , it merged with McDonnell Aircraft in 1967 to form McDonnell Douglas , where it operated as a division. McDonnell Douglas merged with Boeing in 1997. The company was founded as the Douglas Company by Donald Wills Douglas Sr. on July 22, 1921, in Santa Monica, California , following dissolution of

SECTION 50

#1732772820773

2912-460: Was announced, McDonnell bought 1.5 million shares of Douglas stock to help Douglas meet "immediate financial requirements". The merged company was based at McDonnell's facility in St. Louis, Missouri . It adopted a modified version of Douglas' logo. Donald Wills Douglas Sr. became honorary chairman of the merged company, a post he would hold until his death in 1981. Douglas Aircraft Company continued as

2968-670: Was forced down over the Atlantic and sank (the DWC prototype was then rechristened, and joined the other two in completing the North American leg of the flight). After the success of this flight, the Army Air Service ordered six similar aircraft as observation aircraft. The success of the DWC established the Douglas Aircraft Company among the major aircraft companies of the world and led it to adopt

3024-561: Was granted the contract to research on intercontinental warfare. Project RAND later become the RAND Corporation . Douglas continued to develop new aircraft, including the successful four-engined Douglas DC-6 (1946) and its last propeller-driven commercial aircraft, the Douglas DC-7 (1953). The company had moved into jet propulsion, producing its first for the U.S. Navy — the straight-winged F3D Skyknight in 1948 and then

3080-612: Was similar to the F-4 Phantom II ; however, the new fuselage and wing design provided greater lift and a better climb profile than the F-4. The TF30 was found to be ill-adapted to the demands of air combat and was prone to compressor stalls at high angle of attack (AOA), if the pilot moved the throttles aggressively. Because of the Tomcat's widely spaced engine nacelles, compressor stalls at high AOA were especially dangerous because they tended to produce asymmetric thrust that could send

3136-430: Was so large, the mail girls used roller skates to deliver the intracompany mail. By the end of World War II, Douglas had facilities at Santa Monica, El Segundo , Long Beach , and Torrance, California , Tulsa and Midwest City , Oklahoma, and Chicago, Illinois . On November 30, 1928, the company was reorganized as the Douglas Aircraft Company. In 1934, Douglas produced a commercial twin-engined transport plane ,

#772227