Misplaced Pages

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78-434: The design originally called for an engine of 7,500  lbf (33 kN) thrust at sea level static conditions without afterburner and 10,900 lbf thrust with afterburner. A more powerful model 9,500/13,700 lbf thrust version was intended to replace the earlier engines in the various airframes. In total, thirteen different variations were planned. The projected need for the higher-power engines led BuAer to place

156-509: A radar -operated tail turret designed by Westinghouse, soon removed in favor of electronic countermeasure equipment. Although some bombing missions would be carried out early in the Vietnam War , most bombing would be carried out by more manoeuvrable aircraft, and the Skywarrior would serve mostly as a tanker and electronic warfare support aircraft. Prior to the initial operational capability of

234-403: A US Air Force program decided to modify an A-3 for F-15 radar tests, and the only available airframe was stored at Naval Air Station Alameda since the fleet shutdown. Hughes added that aircraft to the bailment, and ferried the aircraft to Van Nuys for modifications. An entire nose section was removed from a stricken F-15B at AMARC at Davis-Monthan AFB , Arizona and grafted onto the front of

312-545: A contract for the production of two flight-capable prototypes and a single static airframe to the company. Douglas sourced significant portions of the aircraft, including responsibility for the turbojet engines, radar , tail-mounted turret , electrical generators and various other secondary systems, from the Westinghouse Electric Corporation ; this heavy reliance on Westinghouse allegedly caused some discomfort to Douglas. In particular, development of

390-466: A former A-3 bombardier/navigator himself, made the final decision to retire the type. Being the heaviest aircraft to take off from a carrier, the Skywarrior was prone to accidents. "Ultimately, of 283 Skywarriors of various models built, around 120 (42%) were destroyed or crippled in accidents and combat. In 67% of accidents, at least one crew member died." Of these losses, 7 were in Vietnam, of which 2 were

468-534: A higher-power J40-WE-12 non-afterburning version developing 9,500 lbf (42 kN) thrust, with better fuel consumption, was proposed for the A3D, and an afterburning version (J40-WE-10) developing 13,700 lbf (61 kN) thrust was proposed for the fighter projects. Both versions were accepted and became the engines the airframes were designed to use. The lower-powered early development models were now intended to be used only for ground and initial flight testing until

546-418: A percent) can safely be neglected. The 20th century, however, brought the need for a more precise definition, requiring a standardized value for acceleration due to gravity. The pound-force is the product of one avoirdupois pound ( exactly 0.45359237 kg) and the standard acceleration due to gravity , approximately 32.174049 ft/s (9.80665 m/s ). The standard values of acceleration of

624-571: A redesign to accept the J71 engine after the loss of six aircraft and four pilots. The decision to move the Demon to the J71 had occurred long before the initial production batch emerged and with the development of a suitable afterburner for the J71 being protracted, BuAer decided to accept the early aircraft with Westinghouse J40-WE-22A and -22 engines. This decision came under Congressional review in 1955 and drew sharp criticism from Congress. Time Magazine called

702-483: A requirement to develop a long-range, carrier-based attack plane that could deliver either a 10,000 lb (4,500 kg) bomb load or a nuclear weapon . The envisioned aircraft was intended to be operated from the planned United States -class " supercarriers ," which were significantly larger than the USN's existing carriers, thus the specification set a target loaded weight of 100,000 lb (45,000 kg). Additionally,

780-478: A result, J40-WE-6 engines without afterburners had to be used for initial testing, causing delays in flight test programs. Early on even the low-powered versions of the engine were considered unusable because of reliability problems. The A3D would prove successful with alternate engines, but the F3H-1 was relegated to subsonic performance using the lower-powered engine and continued to be subsonic even after substitution of

858-464: A second source production contract with Ford Motor Company, Lincoln Mercury Division for both J40-WE-10 and J40-WE-12 engines. The higher-powered versions proved to have a flawed compressor design and lacked a suitable control system. This left the Navy with only the earlier, lower-power engines. These were eventually used for early flight testing, but proved to be largely unusable. A particularly notorious use

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936-479: A side-by-side arrangement with the pilot's station on the port side having full flight controls. On initial variants, a third crew member, who also acted as a gunner for the twin tail-mounted 20mm cannon that briefly equipped the original bomber version of the A3D/A-3A (removed and replaced by ECM equipment), sat behind the pilot in an aft-facing seat. The third crewman station had the sextant for celestial navigation and

1014-494: A similar mission. The EA-3B carried a crew of seven, with flight crew of three in the cockpit and an Electronic Warfare Officer and three electronic systems operators/evaluators in the converted weapons bay. It offered unique electronic reconnaissance capabilities in numerous Cold War-era conflicts and the Vietnam War. A handful of EA-3Bs remained in service long enough to participate in the first Gulf War in 1991 . The Skywarrior

1092-542: A small number of TA-3B aircraft for training Naval Flight Officers in the Vigilante's radar and navigation systems. The Skywarrior's strategic bombing role faded after 1964, briefly being complemented by the A3J Vigilante. Soon afterward, the Navy abandoned the concept of carrier-based strategic nuclear weaponry for the successful Polaris missile-equipped Fleet Ballistic Missile submarine program and all A-5As were converted to

1170-494: Is a unit of mass ; nor should these be confused with foot-pound (ft⋅lbf), a unit of energy , or pound-foot (lbf⋅ft), a unit of torque . The pound-force is equal to the gravitational force exerted on a mass of one avoirdupois pound on the surface of Earth . Since the 18th century, the unit has been used in low-precision measurements, for which small changes in Earth's gravity (which varies from equator to pole by up to half

1248-462: Is approximately equal to the force unit (pound-force). This is convenient because one pound mass exerts one pound force due to gravity. Note, however, unlike the other systems the force unit is not equal to the mass unit multiplied by the acceleration unit —the use of Newton's second law , F = m ⋅ a , requires another factor, g c , usually taken to be 32.174049 (lb⋅ft)/(lbf⋅s ). "Absolute" systems are coherent systems of units: by using

1326-464: The Allison J71 engine. The J40 program was terminated in 1955, by which time all the aircraft it was to power were either grounded, cancelled or redesigned to use alternative engines. The J40's failure was among those that affected the most military programs. The program failure was primarily due to lack of investment in research and experimental resources by Westinghouse, leaving them unable to resolve

1404-479: The EKA-3B model could readily swing between performing strike, refuelling, and electronic warfare duties as required. Numerous other models of the type were developed, leading to the type being used for aerial reconnaissance and as a trainer aircraft as well. Production of the type ceased in 1961. The Skywarrior had a 36° degree swept wing and two Pratt & Whitney J57 turbojet engines. Early prototypes had used

1482-682: The U.S. Navy's Polaris-armed Fleet Ballistic Missile submarines , the A-3 was the Navy's critical element in the U.S. nuclear deterrent. Squadrons were established in two Heavy Attack Wings (HATWINGs), with one wing initially established at Naval Air Station North Island , California before relocating to Naval Air Station Whidbey Island , Washington in December 1957 while the other wing was initially established at Naval Air Station Jacksonville , Florida before relocating to Naval Air Station Sanford , Florida. The wing at NAS Whidbey Island would disestablish in 1959 but

1560-423: The Westinghouse Electric Corporation , including its early Westinghouse J40 turbojet engines, which failed to meet promises and were replaced by the rival Pratt & Whitney J57 engine by mid-1953. On 28 October 1952, the prototype XA3D-1 performed the type's maiden flight . On 31 March 1956, the Skywarrior entered squadron service with the Navy. Initially used in the nuclear-armed strategic bomber role,

1638-570: The Westinghouse J40 engine proved to be incapable of meeting development schedules or performance promises; Heinemann later commented that "the first thing we learned was that the J40 was not powerful enough". Even prior to the first flight being conducted, Douglas was considering switching to rival manufacturer Pratt & Whitney 's J57 engine, which was heavier, but allowed the overall aircraft to be lighter as it used less fuel. On 28 October 1952,

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1716-530: The kilogram-force , a unit of force whose use has been deprecated since the introduction of SI. Douglas A-3 Skywarrior The Douglas A-3 Skywarrior is a jet-powered strategic bomber that was developed and produced by the Douglas Aircraft Company . It was designed by Douglas on behalf of the United States Navy , which sought a carrier -capable strategic bomber. In July 1949, Douglas

1794-620: The slug . A slug has a mass of 32.174049 lb. A pound-force is the amount of force required to accelerate a slug at a rate of 1 ft/s , so: 1 lbf = 1 slug × 1 ft s 2 = 1 slug ⋅ ft s 2 {\displaystyle {\begin{aligned}1\,{\text{lbf}}&=1\,{\text{slug}}\times 1\,{\tfrac {\text{ft}}{{\text{s}}^{2}}}\\&=1\,{\tfrac {{\text{slug}}\cdot {\text{ft}}}{{\text{s}}^{2}}}\end{aligned}}} In some contexts,

1872-530: The strategic bombing mission. The USN had a growing awareness that it could operate in a broader role than had been previously possible, and that the strategic bomber fleet operated by the United States Air Force (USAF) was unable to reach large parts of the world, a lesser limitation to forward deployed USN aircraft carrier groups and their air wings. In January 1948, the Chief of Naval Operations issued

1950-412: The 1970s. During World War II , the United States Navy (USN) began to explore the concept of operating jet-powered aircraft from its aircraft carriers . Success encouraged further development of the concept; early in the post-war years, officials within the USN began to investigate the use of jet power as a potential means of operating larger carrier-based aircraft that would be capable of performing

2028-579: The A-3. ) In contrast, the US Air Force's B-66 Destroyer, not subject to the weight requirements for carrier operations, was equipped with ejection seats throughout its service life. The documented history of mechanical failures in the A3D/A-3 showed a rate well above average. Originally, the Skywarrior bombers were assigned to all attack carriers, which included the World War II-era Essex class and

2106-587: The April 1949 edition of the Naval Aviation Confidential Bulletin by Lieutenant Commander Neil D. Harkleroad of the Bureau of Aeronautics Power Plant Division, "The engine has been operating successfully to date." As of that writing, the 50-hour flight substantiation test was to have been accomplished by June 1949 and the 150-hour qualification test by December 1949. The J40 was designed to deliver twice

2184-549: The J40-WE-6, was to power the Douglas A-3D Skywarrior twin-engine carrier-based bomber. The J40-8 was only a little over 40 inches (1,000 mm) in diameter but 25 feet (7.6 m) long, with accessories and including the afterburner. It weighed almost 3,500 pounds (1,600 kg), the -6 being almost 7 feet (2.1 m) shorter and about 600 pounds (270 kg) lighter, because it did not have an afterburner. In 1949,

2262-464: The Navy's grounding of all Westinghouse-powered F3H-1 Demons a "fiasco", with 21 unflyable planes, that could be used only for Navy ground training at a loss of $ 200 million. One high point of the J40 was the 1955 setting of an unofficial time-to-climb record, in a Demon, of 10,000 feet (3,000 m) in 71 seconds. A replacement engine could not be easily fitted into the grounded Demons, as the fuselage had to be redesigned and enlarged. When this redesign

2340-561: The RA-5C Vigilante reconnaissance variant. Many A-3Bs were converted to a combination tanker-electronic warfare aircraft. Skywarriors saw some use in the conventional bombing and mine-laying role (A-3B) during the Vietnam War from 1964 through 1967, often to deliver Mk84 2,000 pounds (910 kg) bombs. The A-3 found subsequent service in the tanker (KA-3B), photographic reconnaissance (RA-3B), electronic reconnaissance (EA-3B), and electronic warfare (ERA-3B, EKA-3B) roles. For most of

2418-445: The Skywarrior had been designed to carry larger and bulkier bombs than it ever would in service due to the rapid improvements made in weapons technology. Despite this, at the Navy's insistence, the aircraft was qualified for an 'overload' payload capacity of 84,000 lb (38,000 kg), the testing of which would establish a weight-related record for carrier operations. Because of its cumbersome size, and less-than-slender profile, it

Westinghouse J40 - Misplaced Pages Continue

2496-399: The Skywarrior was designated A3D (third Attack aircraft from Douglas Aircraft). In September 1962, the new Tri-Services designation system was implemented and the aircraft was redesignated A-3 . Where applicable, pre-1962 designations are listed first, post-1962 designations in parentheses. The U.S. Air Force ordered 294 examples of the derivative B-66 Destroyer, most of which were used in

2574-677: The Southeast Asia area. With 12 camera stations the RA-3B was well equipped to perform cartographic mapping of areas where no detail maps existed. With IR gear installed, the RA-3B was used at night to monitor the movement of troops down roads and trails in Laos. Other locations included Det Tango at Don Muang Royal Thai Air Force Base in Bangkok, Thailand, Det Southpaw at RAAF Base Townsville , Australia, as well as work out of Osan Air Base , South Korea. During

2652-593: The Thunderbird assets to the contract, prepping them for ferry at Deer Valley airport, and relocating them to Mojave, California and Tucson, Arizona for long-term storage. In December 1996, Raytheon bought the aerospace units of Hughes Aircraft Company. Hughes Aeronautical Operations, now a part of Raytheon Systems, continued to operate the A-3s from their base at Van Nuys Airport , California. These aircraft have participated in several military air shows, telling visitors that

2730-519: The US Navy decided to end logistic support for the civilian operated testbeds. Rather than abandon the A-3, Hughes, Westinghouse and Raytheon agreed to acquire the remaining A-3s and spares from the Navy, allowing their test fleets to continue to operate and saving the US Navy the cost of storage and disposal. As the plan matured, two other contractors, Thunderbird Aviation and CTAS also elected to participate in similar agreements, with eleven A-3s spread between

2808-406: The USN sought for this bomber to possess greater speed and range than its existing North American AJ Savage fleet. A total of eight aircraft manufacturers produced responses to the specification, but all except Douglas Aircraft Company and Curtiss-Wright would drop out, declaring that there was no means that the requirements could be met within the 100,000 lb weight limitation. Uncertainty over

2886-466: The USN's existing carriers. Heinemann had reasoned (correctly) that as technology developed, the size and weight of nuclear weapons would substantially decrease, which increased the rationale for designing a more compact bomber. However, figures such as USAF general Hoyt Vandenberg ridiculed Heinemann's proposal as "making irresponsible claims". During this period, the USN and USAF were vigorous rivals, each seeking to maintain funding for its projects at

2964-600: The Vietnam War, EA-3Bs of Fleet Air Reconnaissance Squadron 1 (VQ-1) flew from Da Nang Air Base in South Vietnam, providing continuous electronic reconnaissance capability over the area, including the Ho Chi Minh Trail and all the way north to Haiphong harbor. This was known as VQ-1 Det.B. The aircrew and ground support personnel were temporarily assigned from their home base at Naval Air Station Atsugi , Japan and after 1970, Naval Air Station Agana , Guam. After Det B

3042-546: The Vietnam War, the A-3 attack aircraft were modified to KA-3B tankers while some were modified into a multi-mission tanker variant, the EKA-3B, which was a real workhorse for the carrier air wing. Electronic jamming equipment was added without removing tanker capability so the EKA-3B could jam enemy radar while waiting to refuel tactical aircraft. Eventually, the EKA-3B was replaced by the smaller dedicated Grumman KA-6D Intruder tanker, which although it had less capacity and endurance,

3120-533: The XJ54, also failed to find a United States market. The J57 would also replace, for the U.S. Navy, the disastrous Westinghouse J40 that never fully materialized in acceptable form Westinghouse Electric Corporation established the Westinghouse Aviation Gas Turbine Division (AGT) in 1945. Along with General Electric , Westinghouse had extensive experience in turbine design that put them in

3198-450: The aircraft. Racks and equipment were installed in the cabin, and the aircraft was used by Hughes and the USAF for F-15 software development. In 1994, Westinghouse decided to terminate their agreement with the Navy, and Thunderbird added their aircraft to the Thunderbird bailment. In 1996, Thunderbird Aviation went into receivership, and Hughes, through mutual cost savings to the government, added

Westinghouse J40 - Misplaced Pages Continue

3276-433: The defensive electronic counter measures equipment. Later electronic reconnaissance variants could accommodate a crew of seven with the flight crew consisting of a pilot, co-pilot and navigator plus four electronic systems operators occupying stations in the former bomb bay in the spacious fuselage. Efforts to reduce weight to make the aircraft suitable for carrier operations had led to the deletion of ejection seats during

3354-539: The design process for the Skywarrior, based on the assumption that most flights would be at high altitude. A similar arrangement with an escape tunnel had been used on the F3D Skyknight . Aircrews began joking morbidly that "A3D" stood for "All Three Dead". (In 1973, the widow of a Skywarrior crewman killed over Vietnam sued the McDonnell Douglas Aircraft Company for not providing ejection seats in

3432-448: The emergence of effective ballistic missiles led to this mission being deprioritized by the early 1960s. Throughout the majority of its later service life, the Skywarrior was tasked with various secondary missions which included use as an electronic warfare platform, tactical reconnaissance aircraft, and high-capacity aerial refueling tanker. It was among the longest serving carrier-based aircraft in history, having entered service during

3510-429: The engines, lying almost flat, and its vertical stabilizer was hinged to starboard. Capacious internal fuel tanks provided long range. The early A-3 variants had a crew of three: pilot, bombardier/navigator (BN) and crewman/navigator (aka: third crewman). An unusual cockpit configuration was incorporated with the three crew sitting under a framed canopy. In the raised compartment, the pilot and bombardier/navigator sat in

3588-501: The expense of the other in a time marked by drastically declining defense budgets; specifically, USAF officials frequently voiced their open opposition to the construction of the United States -class carriers. In late 1948, both Douglas and Curtiss-Wright were awarded preliminary design contracts to further develop and refine their proposals. While Douglas managed to maintain the take-off weight at 68,000 lb, Curtiss were unable to meet

3666-499: The five operators. The fleet spares from ASO (Aviation Supply Office) were distributed between the contractors evenly, and warehouses were emptied all over the US. Due to misunderstandings and reorganizations within the US Navy, the worldwide ASO assets were scrapped, not getting to the contractors. In early 1993, CTAS decided that they no longer had use for their aircraft, and Hughes had several programs needing additional assets. In early 1994,

3744-410: The high-powered J71 could not restore its performance. The F3H-1N Demon single-engine jet fighter was initially a severe disappointment, due to the unreliability of the J40 and the difficulties of flying the much heavier airframe with the lower-powered J40-WE-22A engines. The airframe design had assumed the higher-powered J40-WE-10 would be the power plant. These first production Demons were grounded for

3822-469: The high-powered engines became available. Development of the big engine was protracted. The all-important 150-hour qualification test that was to have been accomplished in December 1949 was not completed until January 1951, a year behind schedule. The afterburner was particularly troublesome – the afterburning version of the engine, the J40-WE-8, did not pass its 150-hour qualification until August 1952. As

3900-464: The higher-power Allison J71. It has been stated, that although considered failures, the F3H-1 could have been competitive with early supersonic Air Force's Century Series fighters had the original engines delivered on their design specifications. In fact, the Demon that emerged from development was a missile-armed all-weather fighter over 8,000 lb (3,600 kg) heavier than the XF3H-1 had been, and even

3978-409: The immediate-postwar Midway class. The Skywarrior could carry up to 12,000 lb (5,400 kg) of weaponry in the fuselage bomb bay , which in later versions was used for sensor and camera equipment or additional fuel tanks. An AN/ASB-1A bomb-director system was initially installed, later replaced by a revised AN/ASB-7 with a slightly reshaped nose. Defensive armament was two 20mm cannons in

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4056-424: The intended Westinghouse J40, a powerplant that proved to be disastrous and was subsequently canceled. The turbojets could be supplemented by a provision for twelve 4,500  lbf (20  kN ) thrust JATO bottles. The aircraft had a largely conventional semi- monocoque fuselage, with the engines in underwing nacelles. Flight controls were hydraulic, and for storage below deck, the A-3's wings folded outboard of

4134-459: The issues with the various models of the engines. In 1953 Westinghouse worked with Rolls-Royce to offer engines based on the Avon , which had similar performance but matured into an excellent design of even higher output. Westinghouse was out of the aircraft engine business by 1965 when their 6,200 lbf (28 kN) thrust, scaled-down version of the 12,000 lbf (53 kN) Avon 300-series engine,

4212-514: The lead over established aviation engine manufacturers, who had little experience with these entirely new design concepts. While most early engines in the US were redesigned versions of British jets, the J30 was the first truly American-designed turbojet to run, and saw use in the McDonnell FH Phantom . The enlarged J34 was obsolete when introduced, but moderately successful. A new design following

4290-465: The mid-1950s and withdrawn from use in 1991. Throughout its service, the Skywarrior was the heaviest operational aircraft to operate from an aircraft carrier , which contributed to its nickname of " Whale ". The Skywarrior is one of only three U.S. Navy attack aircraft to enter service in the strategic bomber role. The first was its predecessor, the North American AJ Savage . Its successor,

4368-431: The more generous 100,000 lb target during this phase, and thus were eliminated from consideration. During April 1949, the USN's critics succeeded in getting the United States -class carriers cancelled; this outcome validated Heinemann's decision to focus on a design that could operate from the navy's smaller Midway -class aircraft carriers . During July 1949, the USN, recognizing the suitability of Douglas' design, awarded

4446-453: The performance and requirements of both engines and bombs were major contributing factors towards this climate of negativity. Ed Heinemann , Douglas' chief designer, later to win fame for the A-4 Skyhawk , fearing that the United States class was vulnerable to cancellation, proposed a significantly smaller aircraft of 68,000 lb (31,000 kg) loaded weight, capable of operating from

4524-478: The plane continued to be valuable for its load capacity compared to corporate jets, and its performance compared to small airliners. On 30 June 2011, the last flyable EA-3B, BuNo 144865 / FAA registration N875RS, a Raytheon aircraft, arrived at Naval Air Station Pensacola, Florida for retirement and display at the National Naval Aviation Museum . Note: under the original Navy designation scheme,

4602-399: The prototype XA3D-1 performed the type's maiden flight ; flown by George Jansen , this initial test flight was carried out with a high degree of secrecy. Early on, the aircraft was found to handle particularly well in flight, in part due to the attention Heinemann and the design team had paid to the hydraulically -boosted control surfaces. On 16 October 1953, the first YA3D-1 , powered by

4680-590: The rapid industry progress was needed. The J40 represented a big opportunity for Westinghouse to become a prominent player in the turbojet engine market. The U.S. Navy showed great confidence in the company when it bet the success or failure of a new generation of jets on Westinghouse over three other engine companies. It was in June 1947 that the Navy's Bureau of Aeronautics contracted for its development. The prototype engine first ran in November 1948. According to an article in

4758-499: The result of combat. The A-3 had been used as a civilian operated testbed for many years before the type's retirement from US Navy, with Hughes Aircraft Company using the type as a testbed for developing the weapons system for the General Dynamics–Grumman F-111B and Grumman F-14 Tomcat , with Westinghouse and Raytheon also using the A-3 as a testbed. On the retirement of the type from US Navy service in 1991,

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4836-497: The rival J57 engine, made its first flight. Considerable development problems, largely associated with the original J40 engines, had delayed the introduction of the Skywarrior until 31 March 1956. The A-3 was, by far, the largest and heaviest aircraft ever designed for routine use on an aircraft carrier, though ironically it was the smallest proposal among other proposals that could only be deployed on even larger carriers not yet in service. As had been predicted by Heinemann early on,

4914-452: The slug as the unit of mass, the "gravitational" FPS system (left column) avoids the need for such a constant. The SI is an "absolute" metric system with kilogram and meter as base units. The term pound of thrust is an alternative name for pound-force in specific contexts. It is frequently seen in US sources on jet engines and rocketry, some of which continue to use the FPS notation. For example,

4992-525: The squadrons which had made up the wing would later transition to the EKA-3B variant, eventually forming the nucleus for the Navy's Grumman EA-6B Prowler community, while the wing at NAS Sanford would convert to the A3J Vigilante (later A-5A) in the nuclear heavy attack mission, followed by conversion to the RA-5C and transition to the reconnaissance attack mission. The Vigilante wing would also continue to retain

5070-1619: The standard gravitational field ( g n ) and the international avoirdupois pound (lb) result in a pound-force equal to 32.174 049   ⁠ ft⋅lb / s ⁠ (4.4482216152605 N). 1 lbf = 1 lb × g n = 1 lb × 9.80665 m s 2 / 0.3048 m ft ≈ 1 lb × 32.174049 f t s 2 ≈ 32.174049 f t ⋅ l b s 2 1 lbf = 1 lb × 0.45359237 kg lb × g n = 0.45359237 kg × 9.80665 m s 2 = 4.4482216152605 N {\displaystyle {\begin{aligned}1\,{\text{lbf}}&=1\,{\text{lb}}\times g_{\text{n}}\\&=1\,{\text{lb}}\times 9.80665\,{\tfrac {\text{m}}{{\text{s}}^{2}}}/0.3048\,{\tfrac {\text{m}}{\text{ft}}}\\&\approx 1\,{\text{lb}}\times 32.174049\,\mathrm {\tfrac {ft}{s^{2}}} \\&\approx 32.174049\,\mathrm {\tfrac {ft{\cdot }lb}{s^{2}}} \\1\,{\text{lbf}}&=1\,{\text{lb}}\times 0.45359237\,{\tfrac {\text{kg}}{\text{lb}}}\times g_{\text{n}}\\&=0.45359237\,{\text{kg}}\times 9.80665\,{\tfrac {\text{m}}{{\text{s}}^{2}}}\\&=4.4482216152605\,{\text{N}}\end{aligned}}} This definition can be rephrased in terms of

5148-484: The supersonic North American A-5 Vigilante initially supplanted the A-3 in the strategic bomber role (1961-1963) but was then converted to the tactical strike reconnaissance role. A modified derivative of the Skywarrior, the B-66 Destroyer , served in the United States Air Force , where it was operated as a tactical bomber, electronic warfare aircraft, and aerial reconnaissance platform up until its withdrawal during

5226-428: The term "pound" is used almost exclusively to refer to the unit of force and not the unit of mass. In those applications, the preferred unit of mass is the slug, i.e. lbf⋅s /ft. In other contexts, the unit "pound" refers to a unit of mass . The international standard symbol for the pound as a unit of mass is lb. In the "engineering" systems (middle column), the weight of the mass unit (pound-mass) on Earth's surface

5304-549: The thrust of engines currently in service, allowing the J40-WE-8 with afterburner to power many of the new Navy carrier-based fighters with a single engine. These included the Grumman XF10F Jaguar variable-sweep wing general-purpose fighter, the McDonnell F3H Demon and Douglas F4D Skyray interceptors. Growth to over 15,000 lbf (67 kN) of thrust in afterburner was projected. A version without afterburner,

5382-556: The thrust produced by each of the Space Shuttle 's two Solid Rocket Boosters was 3,300,000 pounds-force (14.7  MN ), together 6,600,000 pounds-force (29.4 MN). The value adopted in the International Service of Weights and Measures for the standard acceleration due to Earth's gravity is 980.665 cm/s , value already stated in the laws of some countries. This value was the conventional reference for calculating

5460-521: The variable-sweep wing and the control systems. The J40 engine issues were of secondary importance during the prototype flight trials. Data from Flight. Related lists Pound (force) The pound of force or pound-force (symbol: lbf , sometimes lb f , ) is a unit of force used in some systems of measurement , including English Engineering units and the foot–pound–second system . Pound-force should not be confused with pound-mass (lb), often simply called "pound", which

5538-422: Was awarded the contract to produce its design, having bested eight other aircraft companies' submissions. Unlike rival designs, which had aimed for a 100,000 lb (45,000 kg) maximum take-off weight, the Skywarrior was developed for a 68,000 lb (31,000 kg) take-off weight, facilitating its use from the navy's existing Midway -class aircraft carriers . Large portions of the aircraft were produced by

5616-413: Was deployed in greater numbers within the carrier's air wing. Two additional Naval Reserve units were established in the early 1970s as air refueling squadrons, VAQ-208 and VAQ-308 , at Naval Air Station Alameda , California. Both units operated aircraft with electronic warfare equipment removed and were redesignated as KA-3Bs. VAK-208 and VAK-308 were decommissioned in the early 1990s. The EA-3 variant

5694-726: Was disestablished, VQ-1 provided detachments of two EA-3B aircraft that deployed with Western Pacific and Indian Ocean (WESTPAC/IO) bound aircraft carrier battle groups up until the late 1980s when it was replaced by the Lockheed ES-3A Shadow . In addition, a version of the A-3B was modified into the RA-3B and used in Vietnam as a photo reconnaissance aircraft. Heavy Photographic Squadron 61 (VAP-61) at Naval Air Station Agana, Guam and sister squadron VAP-62 at Naval Air Station Jacksonville, Florida furnished crews and flew out of Da Nang AB performing mapping and intelligence gathering flight over

5772-461: Was done to accommodate the J71, the wing area was also enlarged to counter the increased weight of the all-weather aircraft. The F4D Skyray that had been designed to more easily accept different engines emerged in production powered by the Pratt & Whitney J57 . The A3D emerged with non-afterburning J57 engines as well. The F10F-1 program was cancelled primarily due to unsolvable aerodynamic issues with

5850-612: Was in the McDonnell F3H-1N Demon , which proved to be dangerously underpowered with the smaller engines. The design was quickly grounded after repeated incidents caused by flying the now overweight airframe and a number of engine failures that led to the loss of the aircraft. A government investigation of the F3H-1N program issue failed to determine if pilots had been lost due solely to the engine issues. The grounded airframes were either scrapped or used for ground training. The F3H-2N used

5928-413: Was nicknamed "The Whale". By the end of the 1950s, it was becoming clear that the nuclear mission of the Skywarrior would be passed onto ballistic missiles ; however, its high weight clearance and size meant that the aircraft would be useful in various other capacities. Accordingly, large numbers of Skywarriors were retrofitted as aerial refuelling tankers or as electronic warfare platforms; notably,

6006-460: Was used in critical electronic intelligence (ELINT) roles operating from aircraft carrier decks and ashore supplementing the larger Lockheed EP-3 . Its last service was as an ELINT platform during Desert Storm. The EA-3B variant was modified for electronic intelligence against the Warsaw Pact . Missions were flown around the globe beginning in 1956, with the U.S. Air Force EB-47 Stratojet flying

6084-442: Was withdrawn from USN service during September 1991, the last examples of the type being retired on 27 September 1991. U.S. Navy RDT&E units, notably Naval Air Systems Command ( NAVAIR ) activities at Naval Air Station Point Mugu and NAWS China Lake , attempted to retain their A-3 testbeds. These ambitions were ultimately unsuccessful when Vice Admiral Richard Dunleavy , as Deputy Chief of Naval Operations for Air Warfare and

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