125-745: The Vickers-Armstrongs V-1000 was a proposed jet-powered cargo aircraft that was designed to meet a requirement issued by the British Ministry of Supply which sought a strategic transport for the Royal Air Force (RAF) to support its strategic bomber fleet, particularly the V-bombers . The design bears many similarities to the Vickers Valiant , one of the V-bombers, but also featured substantial changes. In addition to its military application, both
250-551: A Boeing 737-200 that suffered catastrophic cabin failure mid-flight, was primarily caused by the aircraft's continued operation despite having accumulated more than twice the number of flight cycles that the airframe was designed to endure. For increased passenger comfort, several modern airliners, such as the Boeing 787 Dreamliner and the Airbus A350 XWB , feature reduced operating cabin altitudes as well as greater humidity levels;
375-535: A MoS spokesperson spoke in-depth on the V-1000 and its termination, observing that the programme had taken "long than was hoped to overcome some of the programs of meeting the specification", as well as highlighting the role played by the Britannia in substituting for the intended V-1000 fleet. It was also noted that the civil version was also not intended to be developed due to BOAC having no requirement for it. In addition to
500-506: A bleak future; an order for Britannias, to be built in the same factory, was seen as providing a neat solution for all concerned. By November 1955, press rumours regarding the major shifts in RAF transport policy and the fate of the V-1000 were prolific and of a negative tone. On 11 November 1955, the cancellation of the V-1000 order was announced at a press conference held by the MoS. During the conference,
625-444: A cabin altitude of 24,800 ft (7,600 m) (5.5 psi (0.38 bar)); Gemini used an altitude of 25,700 ft (7,800 m) (5.3 psi (0.37 bar)); and Apollo used 27,000 ft (8,200 m) (5.0 psi (0.34 bar)) in space. This allowed for a lighter space vehicle design. This is possible because at 100% oxygen, enough oxygen gets to the bloodstream to allow astronauts to operate normally. Before launch,
750-460: A cabin altitude of 6,000 ft (1,829 m). Despite this, its cabin altitude was intentionally maintained at 6,000 ft (1,829 m). This combination, while providing for increasing comfort, necessitated making Concorde a significantly heavier aircraft, which in turn contributed to the relatively high cost of a flight. Unusually, Concorde was provisioned with smaller cabin windows than most other commercial passenger aircraft in order to slow
875-567: A cabin atmosphere of 14.5 psi (1.00 bar) for the Space Shuttle orbiter and the International Space Station . An airtight fuselage is pressurized using a source of compressed air and controlled by an environmental control system (ECS). The most common source of compressed air for pressurization is bleed air from the compressor stage of a gas turbine engine; from a low or intermediate stage or an additional high stage,
1000-425: A higher altitude than other newly designed civilian aircraft. Russian engineers used an air-like nitrogen/oxygen mixture, kept at a cabin altitude near zero at all times, in their 1961 Vostok , 1964 Voskhod , and 1967 to present Soyuz spacecraft. This requires a heavier space vehicle design, because the spacecraft cabin structure must withstand the stress of 14.7 pounds per square inch (1 atm, 1.01 bar) against
1125-610: A higher pressure than for the 8,000 ft (2,438 m) altitude of older conventional aircraft; according to a joint study performed by Boeing and Oklahoma State University , such a level significantly improves comfort levels. Airbus has stated that the A350 XWB provides for a typical cabin altitude at or below 6,000 ft (1,829 m), along with a cabin atmosphere of 20% humidity and an airflow management system that adapts cabin airflow to passenger load with draught-free air circulation. The adoption of composite fuselages eliminates
1250-531: A large slice of the global demand for civil aircraft for the foreseeable future. Meanwhile, the Royal Air Force (RAF) had been pursuing development of a new generation of strategic bombers : the Vickers Valiant , the Avro Vulcan , and the Handley Page Victor . Armed with nuclear weapons and powered by jet engines, those aircraft would be entering service during the 1950s as the V-bombers . The first of
1375-706: A lengthy series of questions in the House that went on for weeks. John Peyton characterised it as "this disappointing and retrograde decision". Deputy Leader of the Labour Party George Brown asked "does not this decision mean that the American companies, the Douglas and the Boeing, will, in effect, be so far ahead of us in the next development of the pure jet that we shall have 10 or 20 years to make up at some stage afterwards?",
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#17328517662471500-403: A lengthy statement by Paul Williams , who pointed out that weight had indeed increased, but Rolls-Royce had addressed this by increasing power to offset this effect. He also noted that the aircraft had a built-in margin of safety due to its larger wing. He described the entire issue as "one of the most disgraceful, most disheartening and most unfortunate decisions that has been taken in relation to
1625-455: A manual back-up control system. All exhaust air is dumped to atmosphere via an outflow valve, usually at the rear of the fuselage. This valve controls the cabin pressure and also acts as a safety relief valve, in addition to other safety relief valves. If the automatic pressure controllers fail, the pilot can manually control the cabin pressure valve, according to the backup emergency procedure checklist. The automatic controller normally maintains
1750-535: A manufacturer of large aircraft at its main factory at Brooklands in Surrey. In the interwar period , the company produced the Wellesley , designed by Rex Pierson using the geodetic airframe principle of structural engineer Barnes Wallis . This would later evolve into the famous Wellington bomber , a mainstay of RAF Bomber Command and RAF Coastal Command during World War II . The Cold War -era Valiant V bomber
1875-413: A military transport, being procured for the RAF, and as a commercial airliner, that BOAC would be expected to order. Such a move would mean increased financial support for the program as well as improved access to development and testing resources. According to aviation author Derek Wood, Sir George Edwards , who headed the design, viewed the military variant "as a stepping stone to the civil version", which
2000-666: A number of limited-capacity "Empire routes" that the Boeing could not service, and turned to Vickers for a solution. The result was the Vickers VC10 , with additional power and a smaller fuselage that dramatically improved " hot and high " performance. Although the VC10 was successful in this role, most of the airports for which it had been designed were soon improved sufficiently for the Boeing 707 and Douglas DC-8 to be able to serve them comfortably after all. The VC10 lost its competitive edge, and sold only in limited numbers. The cancellation led to
2125-451: A prediction that proved astonishingly accurate. Air Commodore Arthur Vere Harvey expressed concerns of the industry in general, while William Robson Brown questioned the wisdom of cancelling at such a late date given that £2.3 million had been invested in the project. In response, the Minister of Supply, Reginald Maudling, noted that it was extremely unlikely that other airlines would order
2250-436: A pressure loss incident would be to perform a rapid descent. The designed operating cabin altitude for new aircraft is falling and this is expected to reduce any remaining physiological problems. Both the Boeing 787 Dreamliner and the Airbus A350 XWB airliners have made such modifications for increased passenger comfort. The 787's internal cabin pressure is the equivalent of 6,000 ft (1,829 m) altitude resulting in
2375-436: A pronounced dihedral to keep them clear of the jet exhaust. The elevators were split into four separate sections while the rudder was divided into three separately-controlled pieces. The fuselage consisted of a stringer -skin structure supported by large numbers of light section frames; these frames were attached to Z-section stringers which were in turn rivetted to the skin. A semi-circular spine -like reinforcing beam
2500-514: A scaled-up version of the de Havilland Comet . The wing differed considerably from the Comet; the outer wing, which housed integral fuel tanks on the VC7 and flexible fuel bags on the V-1000, was swept at 28 degrees, while the leading edge of the inner wing, where the engines and air intake were located, was more highly swept at 38 degrees. The engines, buried within the wings, were placed further outboard than
2625-459: A sea-level cabin altitude when cruising at 41,000 ft (12,497 m). One study of eight flights in Airbus A380 aircraft found a median cabin pressure altitude of 6,128 ft (1,868 m), and 65 flights in Boeing 747-400 aircraft found a median cabin pressure altitude of 5,159 ft (1,572 m). Before 1996, approximately 6,000 large commercial transport airplanes were assigned
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#17328517662472750-652: A six-abreast configuration for up to 120 equipped troops. Some of the design features of the VC7 would go on to influence the Vickers VC10 . In particular, the wing arrangement with the various high-lift devices, such as the curved Kuchemann-style wingtips adopted, proved useful in the "hot and high" roles the VC10 would later fill. Additionally, the VC10 was powered by the Conway, albeit in a higher-powered version with much greater bypass ratio. Data from Vickers Aircraft since 1908 General characteristics Performance Vickers-Armstrongs Vickers-Armstrongs Limited
2875-463: A total of six emergency exits. The floor of the main cabin was to be constructed so that it could withstand up to 75lb/sq ft in the center sections while the outer sections were to support up to 150lb/sq ft. On the military version, a total of five positions were to be provided in the cockpit; the intended crew would have been a pair of pilots, a flight engineer , navigator, and signaller. The main cabin would have been furnished with rear-facing seats in
3000-541: A type certificate to fly up to 45,000 ft (13,716 m) without having to meet high-altitude special conditions. In 1996, the FAA adopted Amendment 25-87, which imposed additional high-altitude cabin pressure specifications for new-type aircraft designs. Aircraft certified to operate above 25,000 ft (7,620 m) "must be designed so that occupants will not be exposed to cabin pressure altitudes in excess of 15,000 ft (4,572 m) after any probable failure condition in
3125-615: A whole suite of military products. Armstrong Whitworth were notable for their artillery manufacture at Elswick and shipbuilding at a yard at High Walker on the River Tyne . 1929 saw the merger of the acquired railway business with those of Cammell Laird to form Metropolitan Cammell Carriage and Wagon (MCCW) ; Metro Cammell. In 1935, before rearmament began, Vickers-Armstrongs was the third-largest manufacturing employer in Britain, behind Unilever and ICI . In 1956 Dorothy Hatfield became
3250-485: Is a process in which conditioned air is pumped into the cabin of an aircraft or spacecraft in order to create a safe and comfortable environment for humans flying at high altitudes. For aircraft, this air is usually bled off from the gas turbine engines at the compressor stage, and for spacecraft, it is carried in high-pressure, often cryogenic , tanks. The air is cooled, humidified, and mixed with recirculated air by one or more environmental control systems before it
3375-462: Is distributed to the cabin. The first experimental pressurization systems saw use during the 1920s and 1930s. In the 1940s, the first commercial aircraft with a pressurized cabin entered service. The practice would become widespread a decade later, particularly with the introduction of the British de Havilland Comet jetliner in 1949. However, two catastrophic failures in 1954 temporarily grounded
3500-404: Is rare but has resulted in a number of fatal accidents . Failures range from sudden, catastrophic loss of airframe integrity (explosive decompression) to slow leaks or equipment malfunctions that allow cabin pressure to drop. Any failure of cabin pressurization above 10,000 ft (3,048 m) requires an emergency descent to 8,000 ft (2,438 m) or the closest to that while maintaining
3625-473: Is typical for older jet airliners. A design goal for many, but not all, newer aircraft is to provide a lower cabin altitude than older designs. This can be beneficial for passenger comfort. For example, the Bombardier Global Express business jet can provide a cabin altitude of 4,500 ft (1,372 m) when cruising at 41,000 ft (12,497 m). The Emivest SJ30 business jet can provide
3750-713: The Douglas DC-6 , the Douglas DC-7 , and the Constellation to have certified service ceilings from 24,000 to 28,400 ft (7,315 to 8,656 m). Designing a pressurized fuselage to cope with that altitude range was within the engineering and metallurgical knowledge of that time. The introduction of jet airliners required a significant increase in cruise altitudes to the 30,000–41,000 ft (9,144–12,497 m) range, where jet engines are more fuel efficient. That increase in cruise altitudes required far more rigorous engineering of
3875-695: The VC10 jet airliner, which was used in RAF service as an aerial refuelling tanker until 2013. Vickers-Armstrongs was one of the few British manufacturers of marine diesel engines , notably for Royal Navy S , T-class and Estonian Kalev -class submarines during World War II. After the Great War Vickers needed to diversify when the military contracts ended. Between WWI and the Second World War they introduced ranges of target and sporting rifles and shotguns,
Vickers V-1000 - Misplaced Pages Continue
4000-615: The Vickers machine gun of 1912 used in World War I from Vickers Limited. There were other Vickers machine guns aside from the regular water-cooled model (known universally as the "Vickers"): the Vickers-Berthier (VB) machine gun used by the Indian Army , the Vickers "K" .303 aircraft machine gun developed from it, and the Vickers "S" 40 mm aircraft gun. An unusual machine gun also made
4125-492: The chemical oxygen generators fitted to most planes cannot supply sufficient oxygen. In jet fighter aircraft, the small size of the cockpit means that any decompression will be very rapid and would not allow the pilot time to put on an oxygen mask. Therefore, fighter jet pilots and aircrew are required to wear oxygen masks at all times. On June 30, 1971, the crew of Soyuz 11 , Soviet cosmonauts Georgy Dobrovolsky , Vladislav Volkov , and Viktor Patsayev were killed after
4250-574: The de Havilland Comet , the world's first jet-powered commercial transport aircraft, the Vickers Viscount , the world's first turboprop -powered commercial airliner, and the Bristol Britannia , a turboprop-powered aircraft capable of conducting routine transatlantic flights . All of those designs had their origins in the specifications laid out by the wartime Brabazon Committee . With those aircraft, Britain appeared to be on track to capturing
4375-433: The fuselage ; this stress is proportional to the difference in pressure inside and outside the cabin. In a typical commercial passenger flight, the cabin altitude is programmed to rise gradually from the altitude of the airport of origin to a regulatory maximum of 8,000 ft (2,438 m). This cabin altitude is maintained while the aircraft is cruising at its maximum altitude and then reduced gradually during descent until
4500-419: The inner ear and sinuses and this has to be managed carefully. Scuba divers flying within the "no fly" period after a dive are at risk of decompression sickness because the accumulated nitrogen in their bodies can form bubbles when exposed to reduced cabin pressure. The cabin altitude of the Boeing 767 is typically about 7,000 ft (2,134 m) when cruising at 37,000 ft (11,278 m). This
4625-413: The minimum sector altitude (MSA), and the deployment of an oxygen mask for each seat. The oxygen systems have sufficient oxygen for all on board and give the pilots adequate time to descend to below 8,000 ft (2,438 m). Without emergency oxygen, hypoxia may lead to loss of consciousness and a subsequent loss of control of the aircraft. Modern airliners include a pressurized pure oxygen tank in
4750-608: The serial number XD662 , along with a structural test frame. in March 1953, it was revealed that the Vickers design had been selected as the winner of the MoS competition. In June 1954, the Secretary of State for Air William Sidney, 1st Viscount De L'Isle announced that a production order for the military variant, designated as the V-1000 , was to be placed for the RAF. Detailed development work on
4875-882: The 1980s. Vickers-Armstrong also built the VA-3 hovercraft . The company was also known for its tank designs, starting with the widely used Vickers 6-Ton . It also produced the influential, if never actually produced, Independent A1E1 tank. One of the company's most important designs was the Valentine Infantry Tank, produced in the thousands in World War II. The military vehicle manufacturing interests were divested into Vickers plc , and would later pass to Alvis Vickers , now part of BAE Systems Land and Armaments . Notable Vickers-Armstrongs military vehicles include; Vickers formed its Aviation Department in 1911. The aircraft interests of Armstrong Whitworth were not acquired in
5000-427: The British aircraft industry in recent years." Woods attributes the cancellation as being the result of a lack of understanding of the air transport industry within the British government of the era. Debate on the issue continued, and the V-1000 continued to come up in debate as late as 1957. The V-1000 was an all-metal jet-powered aircraft, having adopted a conventional monoplane configuration and broadly resembling
5125-460: The Comet worldwide. These failures were investigated and found to be caused by a combination of progressive metal fatigue and aircraft skin stresses caused from pressurization. Improved testing involved multiple full-scale pressurization cycle tests of the entire fuselage in a water tank, and the key engineering principles learned were applied to the design of subsequent jet airliners. Certain aircraft have unusual pressurization needs. For example,
Vickers V-1000 - Misplaced Pages Continue
5250-419: The Comet, as well as being physically far larger as an aircraft. The strict and detailed requirements of the specification required extensive testing, such as the heavy use of wind tunnels to cover short-field operations in addition to high-speed cruising flight, while structural and system demands took Vickers into uncharted territories and new entirely new fields. While much of the knowhow had been derived from
5375-510: The Comet. One of the then-innovative features to be used by the V-1000 was its adoption of the Rolls-Royce Conway engine, the world's first turbofan engine. During takeoff, the Conway's power was to have been boosted by water - methanol injection, of which the aircraft was to carry 550 gallons within the inner wing root. Additionally, uprated versions of the Conway engine were under development, which would have been available for use on
5500-572: The Ministry and Vickers also intended to use the same basic design as the VC7 , a six-abreast trans-Atlantic jet airliner for British Overseas Airways Corporation (BOAC). In 1955, by which point the prototype was already largely complete, the Ministry of Supply decided to terminate the V-1000 project in mid-development. By that time, the design had garnered interest from airlines, and had led to re-designs being conducted by competing US manufacturers, influencing
5625-493: The MoS declared that the demand for strategic airlift was immediate, and chose to purchase several Britannias to fill this role. This selection had coincided with political pressure to bolster employment in Northern Ireland , where much of the production of the Comet 2 was to have been conducted under licence by Short Brothers . The Comet 2's cancellation, along with the aborted Supermarine Swift fighter, had left Short's with
5750-524: The RAF. If it had entered commercial service as envisioned, it would have been the first turbofan -equipped airliner to serve long-haul routes. The VC7 proved to be of concern to aircraft manufacturers in the United States, where both Boeing and Douglas were in the process of designing their own jet transports to a very similar requirement from Strategic Air Command . Both companies had responded with designs sized for 2+3 seating (the original 707 design
5875-415: The V-1000. The flying controls of the wing consisted of multiple flaps , the inner set of which being single-slotted and the outer pair being double-slotted, two-section independently operated ailerons , and multi-section dive brakes set across various locations of the upper and lower wing surfaces. The tail surfaces were conventional and adopted a similar shape to that used for the wing; the tailplanes had
6000-507: The V-bombers to enter service was the Valiant. Noting the favourable performance attributes of the Valiant, both the Ministry of Supply (MoS) and Vickers became interested in a prospective transport derivative, as a potential long-range successor to the smaller Comet. The RAF had also noticed a demand for a suitable transport aircraft capable of accompanying the V-bombers on deployments to any part of
6125-424: The VC7 and V-1000; accordingly, the same airframe was to be used for both the civil and military variants. A key innovation of the V-1000 was its intended use of the Rolls-Royce Conway , which was the first production bypass engine, offering both increased range and improved fuel economy. Rolls-Royce Limited was already developing the Conway engine, having performed its first running in 1950, and had demonstrated
6250-413: The VC7 to be made available, including forecasts of its unit price and delivery dates. After reviewing this information, Thomas announced that he would not purchase the VC7 due to its weight increases impacting its performance; according to Woods, the real reason was BOAC wanting to avoid having to support another British aircraft programme in addition to its existing commitments. Many of BOAC's objections to
6375-460: The VC7 was more interesting. Both companies undertook expensive re-designs of their projects to compete, enlarging the fuselage to match the VC7's 3+3 layout and increasing the overall size and weight of their aircraft. When they were re-introduced to the markets in this larger form, the US firms fared considerably better; after an initial order from Pan American Airways , orders started rolling in from around
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#17328517662476500-412: The VC7 were influenced by the Conway engine, which was still in development at that time. Amongst the detracting claims made where that the enclosed engines in the wing would be unable to accept higher powered fan engines; Woods notes that the successful application of such improvements to the military Victor proves that this was entirely possible. Following the cancellation announcement, Mauldling stated to
6625-474: The VC7, as "everyone concerned accepts that we cannot launch an aircraft of this category into the markets of the world unless we first have a home purchaser who will buy and operate it, which is not so in this case." He declined to offer continued financial support to Vickers for the civilian model for this reason; he also claimed that development had been lagging and weight had increased to offset performance. These later claims were attacked several weeks later in
6750-438: The Valiant and there were elements of the design, such as the engines' internal mounting inside the wings, showed this ancestry, areas such as the structure had dramatic differences, the integrity of the cabin and engine bay conforming to fail-safe principles, unlike the preceding Comet. The finalised design for the V-1000 was enlarged beyond that which the RAF had expected; this was so that commonality could be maximised between
6875-452: The Valiant's Rolls-Royce Avon turbojet engine would be necessary. In October 1952, the MoS formally released Air Specification C.132D for the jet-powered transport. Various firms responded with their own submissions to meet the requirement Handley Page offered the HP.97 , which featured a two-level layout that moved the passenger seating above the wing of a design otherwise almost identical to
7000-507: The Valiant's shoulder-mounted wing, which would have left many rows windowless, and also meant that it had long landing gear that BOAC considered unsuitable. Originally designed in the late 1940s, the VC5 attracted little interest and was soon dropped in favour of a more advanced submission by Vickers. Amongst the differences between the VC5 and the VC7 were a larger 12 ft 6 in (3.81 m) fuselage with six-abreast seating for 131 passengers,
7125-536: The Victor. BOAC rejected the design, which led to the more highly modified HP.111 , which was similar in layout but had a modern six-abreast single-deck fuselage . Avro started with their Vulcan design, keeping its tailless delta wing and mating it with a new fuselage, producing the Avro Atlantic (Avro Type 722). As the name implies, the design was specifically intended to offer trans-Atlantic range. Avro boasted that
7250-496: The airframe was designed to endure. Aloha 243 was able to land despite the substantial damage inflicted by the decompression, which had resulted in the loss of one member of the cabin crew; the incident had far-reaching effects on aviation safety policies and led to changes in operating procedures. The supersonic airliner Concorde had to deal with particularly high pressure differentials because it flew at unusually high altitude (up to 60,000 ft (18,288 m)) and maintained
7375-452: The bleed air that is directed to the ECS is then expanded to bring it to cabin pressure, which cools it. A final, suitable temperature is then achieved by adding back heat from the hot compressed air via a heat exchanger and air cycle machine known as a PAC (Pressurization and Air Conditioning) system. In some larger airliners, hot trim air can be added downstream of air-conditioned air coming from
7500-446: The cabin altitude (a representation of the air pressure, see below ) stays above 12,500 ft (3,810 m) for more than 30 minutes, or if the cabin altitude reaches 14,000 ft (4,267 m) at any time. At altitudes above 15,000 ft (4,572 m), passengers are required to be provided oxygen masks as well. On commercial aircraft, the cabin altitude must be maintained at 8,000 ft (2,438 m) or less. Pressurization of
7625-404: The cabin pressure matches the ambient air pressure at the destination. Keeping the cabin altitude below 8,000 ft (2,438 m) generally prevents significant hypoxia , altitude sickness , decompression sickness , and barotrauma . Federal Aviation Administration (FAA) regulations in the U.S. mandate that under normal operating conditions, the cabin altitude may not exceed this limit at
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#17328517662477750-420: The cabin pressure would be automatically maintained at about 6,900 ft (2,100 m), (450 ft (140 m) lower than Mexico City), which is about 790 hPa (11.5 psi) of atmosphere pressure. Some aircraft, such as the Boeing 787 Dreamliner , have re-introduced electric compressors previously used on piston-engined airliners to provide pressurization. The use of electric compressors increases
7875-474: The cabin vent valve accidentally opened before atmospheric re-entry. The aircraft that pioneered pressurized cabin systems include: In the late 1910s, attempts were being made to achieve higher and higher altitudes. In 1920, flights well over 37,000 ft (11,278 m) were first achieved by test pilot Lt. John A. Macready in a Packard-Le Père LUSAC-11 biplane at McCook Field in Dayton, Ohio . The flight
8000-420: The cargo hold is also required to prevent damage to pressure-sensitive goods that might leak, expand, burst or be crushed on re-pressurization. The principal physiological problems are listed below. The pressure inside the cabin is technically referred to as the equivalent effective cabin altitude or more commonly as the cabin altitude . This is defined as the equivalent altitude above mean sea level having
8125-466: The cockpit, giving the pilots more time to bring the aircraft to a safe altitude. The time of useful consciousness varies according to altitude. As the pressure falls the cabin air temperature may also plummet to the ambient outside temperature with a danger of hypothermia or frostbite . For airliners that need to fly over terrain that does not allow reaching the safe altitude within a maximum of 30 minutes, pressurized oxygen bottles are mandatory since
8250-618: The company possessed a major yard on each coast of Britain; the Naval Construction Yard of Vickers at Barrow-in-Furness in Cumbria and the Naval Yard of Armstrong Whitworth at High Walker on the River Tyne . Vickers-Armstrongs was one of the most important warship manufacturers in the world. These interests were renamed as Vickers-Armstrongs Shipbuilders in 1955, changing again to Vickers Limited Shipbuilding Group in 1968. The Barrow yard
8375-448: The conventional cockpit instruments were all mounted outside the chamber, visible through five small portholes. The first attempt to operate the aircraft was again made by Lt. John A. McCready, who discovered that the turbine was forcing air into the chamber faster than the small release valve provided could release it. As a result, the chamber quickly over pressurized, and the flight was abandoned. A second attempt had to be abandoned when
8500-495: The delta wing offered good takeoff performance without the need for flaps or slats that conventional wings would require, while also offering a high cruising speed. Various versions were offered with 2+2 to 3+3 seating, with the added oddity that the seats faced to the rear of the aircraft. The initial submission made by Vickers was designated as the VC5 , which was essentially a slightly-stretched Valiant bomber with windows. It retained
8625-560: The design of the Boeing 707 and Douglas DC-8 . The V-1000 is one of the great "what-ifs" of British aviation, and its cancellation was the topic of considerable debate in the House of Commons . We have handed to the Americans, without a struggle, the entire world market for big jet airliners. During the early 1950s, Britain's civil aircraft industry was releasing and manufacturing a number of competitive and innovative aircraft designs. They include
8750-578: The design's military prospects having turned sour, civil opportunities for the type in the form of the VC-7 had also become clouded. According to Wood, Reginald Maudling , the Minister of Supply , believed in the VC7 and of its value to BOAC. In addition, beyond BOAC, other airlines were interested in operating the VC7. Gordon McGregor , the President of Trans-Canada Air Lines , travelled to Britain to lobby in favour of
8875-481: The design, such as necessitating the use of double-slotted flaps to achieve the short field performance sought, along with the integration of a rear-mounted sizable hydraulic freight elevator for self-loading operations. Crucially, it was recognised that, in order for the aircraft to be economically viable against competing aircraft powered by turboprop engines and traditional piston engines , an engine capable of more thrust and superior specific fuel consumption than
9000-496: The development of larger bombers where crew were required to move about the cabin. The first bomber built with a pressurised cabin for high altitude use was the Vickers Wellington Mark VI in 1941 but the RAF changed policy and instead of acting as Pathfinders the aircraft were used for other purposes. The US Boeing B-29 Superfortress long range strategic bomber was first into bomb service. The control system for this
9125-543: The effect of progressive metal fatigue as the fuselage undergoes repeated stress cycles coupled with a misunderstanding of how aircraft skin stresses are redistributed around openings in the fuselage such as windows and rivet holes. The critical engineering principles concerning metal fatigue learned from the Comet 1 program were applied directly to the design of the Boeing 707 (1957) and all subsequent jet airliners. For example, detailed routine inspection processes were introduced, in addition to thorough visual inspections of
9250-472: The electrical generation load on the engines and introduces a number of stages of energy transfer; therefore, it is unclear whether this increases the overall efficiency of the aircraft air handling system. They do, however, remove the danger of chemical contamination of the cabin , simplify engine design, avert the need to run high pressure pipework around the aircraft, and provide greater design flexibility. Unplanned loss of cabin pressure at altitude/in space
9375-464: The entire crew of Apollo 1 during a 1967 ground test. After this, NASA revised its procedure to use a nitrogen/oxygen mix at zero cabin altitude at launch, but kept the low-pressure pure oxygen atmosphere at 5 psi (0.34 bar) in space. After the Apollo program , the United States used "a 74-percent oxygen and 26-percent nitrogen breathing mixture" at 5 psi (0.34 bar) for Skylab , and
9500-420: The exact stage depending on engine type. By the time the cold outside air has reached the bleed air valves, it has been heated to around 200 °C (392 °F ). The control and selection of high or low bleed sources is fully automatic and is governed by the needs of various pneumatic systems at various stages of flight. Piston-engine aircraft require an additional compressor, see diagram right. The part of
9625-575: The first female engineering apprentice at Vickers-Armstrongs (Aircraft), Brooklands , followed in 1958 by Janet Gulland who was the first female graduate apprentice at the company. In 1960 the aircraft interests were merged with those of Bristol , English Electric and Hunting Aircraft to form the British Aircraft Corporation (BAC). This was owned by Vickers, English Electric and Bristol (holding 40%, 40% and 20% respectively). BAC in turn owned 70% of Hunting. The Supermarine operation
9750-471: The fuselage, and in the beginning not all the engineering problems were fully understood. The world's first commercial jet airliner was the British de Havilland Comet (1949) designed with a service ceiling of 36,000 ft (11,000 m). It was the first time that a large diameter, pressurized fuselage with windows had been built and flown at this altitude. Initially, the design was very successful but two catastrophic airframe failures in 1954 resulting in
9875-400: The improved fuel consumption of the engine; by 1951, the Conway was being developed for a thrust output of 13,000 lb; enough to serve as the powerplant for the V-1000. However, as the V-1000 design was enlarged beyond its original dimensions, the development of a more powerful model of the Conway was necessitated, contributing to delays on the overall project. Construction of the prototype
10000-462: The jet age before them. The VC7 had been cancelled by this point, and a study demonstrated it would be too costly to restart the line. Instead, BOAC ordered the Boeing 707 in October 1956, ironically in a special model to be powered by the Conway. Contrary to BOAC's worries, the Conway proved to have an almost flawless development cycle, and on several occasions outstripped the development of the models it
10125-457: The majority of newly designed commercial aircraft. Aircraft manufacturers can apply for a relaxation of this rule if the circumstances warrant it. In 2004, Airbus acquired an FAA exemption to allow the cabin altitude of the A380 to reach 43,000 ft (13,106 m) in the event of a decompression incident and to exceed 40,000 ft (12,192 m) for one minute. This allows the A380 to operate at
10250-439: The maximum operating altitude of the aircraft. This mandatory maximum cabin altitude does not eliminate all physiological problems; passengers with conditions such as pneumothorax are advised not to fly until fully healed, and people suffering from a cold or other infection may still experience pain in the ears and sinuses. The rate of change of cabin altitude strongly affects comfort as humans are sensitive to pressure changes in
10375-651: The merger and later passed to the Hawker Aircraft group. In 1928 the Aviation Department became Vickers (Aviation) Ltd and soon after acquired Supermarine Aviation Works , which became the Supermarine Aviation Works (Vickers) Ltd and was responsible for producing the revolutionary Spitfire fighter. In 1938, both companies were re-organised as Vickers-Armstrongs (Aircraft) Ltd , and a new 'art deco' headquarters designed by architect C. Howard Crane
10500-571: The metal fatigue cracks that destroyed the Comets were initiated by the small radius corners on the Comet 1's almost square windows. The Comet fuselage was redesigned and the Comet 4 (1958) went on to become a successful airliner, pioneering the first transatlantic jet service, but the program never really recovered from these disasters and was overtaken by the Boeing 707. Even following the Comet disasters, there were several subsequent catastrophic fatigue failures attributed to cabin pressurisation. Perhaps
10625-421: The most prominent example was Aloha Airlines Flight 243 , involving a Boeing 737-200 . In this case, the principal cause was the continued operation of the specific aircraft despite having accumulated 35,496 flight hours prior to the accident, those hours included over 89,680 flight cycles (takeoffs and landings), owing to its use on short flights; this amounted to more than twice the number of flight cycles that
10750-614: The most successful of which were their small-bore .22 rimfire target rifles. These were serious competitors to the Birmingham Small Arms equivalent products, and Vickers .22 target rifles were at the top of the major competitions' results for more than a decade. Initially these rifles were named solely for Vickers, but, after the 1927 amalgamation with Armstrongs, they became Vickers Armstrongs' products. See reference Vickers and Vickers-Armstrongs Martini target rifles and Sporting guns Cabin pressurization Cabin pressurization
10875-624: The new company. Westland bought out Vickers interest along with other partners in 1970. Vickers formed a subsidiary, the Airship Guarantee Company, under the direction of Cdr Dennis Burney solely for the purpose of producing the R100 airship for the government. Between 1911 and 1970, just over 16,000 aircraft were built under the Vickers name; together the 11,462 Wellington and 846 Warwick aircraft (which were structurally similar) make up over 75% of this total. Vickers became renowned as
11000-414: The outer skin, mandatory structural sampling was routinely conducted by operators; the need to inspect areas not easily viewable by the naked eye led to the introduction of widespread radiography examination in aviation; this also had the advantage of detecting cracks and flaws too small to be seen otherwise. Another visibly noticeable legacy of the Comet disasters is the oval windows on every jet airliner;
11125-528: The packs if it is needed to warm a section of the cabin that is colder than others. At least two engines provide compressed bleed air for all the plane's pneumatic systems, to provide full redundancy . Compressed air is also obtained from the auxiliary power unit (APU), if fitted, in the event of an emergency and for cabin air supply on the ground before the main engines are started. Most modern commercial aircraft today have fully redundant, duplicated electronic controllers for maintaining pressurization along with
11250-440: The passengers for routine flights. In 1921, a Wright-Dayton USD-9A reconnaissance biplane was modified with the addition of a completely enclosed air-tight chamber that could be pressurized with air forced into it by small external turbines. The chamber had a hatch only 22 in (560 mm) in diameter that would be sealed by the pilot at 3,000 ft (914 m). The chamber contained only one instrument, an altimeter, while
11375-429: The pilot discovered at 3,000 ft (914 m) that he was too short to close the chamber hatch. The first successful flight was finally made by test pilot Lt. Harrold Harris, making it the world's first flight by a pressurized aircraft. The first airliner to enter commercial service with a pressurized cabin was the Boeing 307 Stratoliner , built in 1938, prior to World War II , though only ten were produced before
11500-489: The preceding Comet to reduce cabin noise and avoid the rear fuselage encountering the jet blast. Finally, while the fuselage section looks similar to other "narrow body" airliners, albeit featuring a more rounded ogive -shaped nose similar to the Comet's (a design feature also copied on the Sud Aviation Caravelle ), the V-1000 and VC7 were both designed for a six-abreast layout, and thus had a much larger diameter than
11625-444: The press that the decision had been made due to both BOAC and the RAF being unwilling to order the type, leaving him without any alternative. BOAC declared that they were perfectly happy with the Britannia for their trans-Atlantic routes, and would remain so until an enlarged de Havilland Comet 4 arrived in a few years. In the end, BOAC's decision would quickly be reversed when it became clear that their competitors were going to enter
11750-453: The pressure was kept at slightly higher than sea level at a constant 5.3 psi (0.37 bar) above ambient for Gemini, and 2 psi (0.14 bar) above sea level at launch for Apollo), and transitioned to the space cabin altitude during ascent. However, the high pressure pure oxygen atmosphere before launch proved to be a factor in a fatal fire hazard in Apollo, contributing to the deaths of
11875-499: The pressurization system". In the event of a decompression that results from "any failure condition not shown to be extremely improbable", the plane must be designed such that occupants will not be exposed to a cabin altitude exceeding 25,000 ft (7,620 m) for more than 2 minutes, nor to an altitude exceeding 40,000 ft (12,192 m) at any time. In practice, that new Federal Aviation Regulations amendment imposes an operational ceiling of 40,000 ft (12,000 m) on
12000-464: The project started following the issuing of the Specification in October 1952, however it was soon recognised that the V-1000 would be substantially more difficult to develop that any previous transport aircraft that had been operated by the RAF as neither the ministry nor industry were experienced in the development of jet aircraft of this scale before. As a concept, the aircraft was more complex than
12125-441: The project was receding; according to Wood, the RAF were having second thoughts about the project. The Air Staff, seeking to reduce expenditure due to pressure from HM Treasury , noted the V-1000 to be one of the most expensive ongoing projects, and thus came to favour its cancellation. By reallocating the budget that had assigned to the V-1000 to other projects, it would have the effect of avoiding their cancellation instead. Around
12250-460: The project's continuation. However, BOAC Chairman Miles Thomas was not as keen on the VC7; the airline had suffered considerable financial hardship due to the crashes of multiple de Havilland Comets , which it had invested heavily in, and BOAC had already committed itself to the improved Comet 4 and had secured permission to procure several Britannias as well. Upon hearing of the V-1000's termination, Thomas called for an up-to-date specification for
12375-399: The proper cabin pressure altitude by constantly adjusting the outflow valve position so that the cabin altitude is as low as practical without exceeding the maximum pressure differential limit on the fuselage. The pressure differential varies between aircraft types, typical values are between 540 hPa (7.8 psi ) and 650 hPa (9.4 psi ). At 39,000 ft (11,887 m),
12500-410: The rate of decompression in the event of a window seal failing. The high cruising altitude also required the use of high pressure oxygen and demand valves at the emergency masks unlike the continuous-flow masks used in conventional airliners. The FAA, which enforces minimum emergency descent rates for aircraft, determined that, in relation to Concorde's higher operating altitude, the best response to
12625-475: The same atmospheric pressure according to a standard atmospheric model such as the International Standard Atmosphere . Thus a cabin altitude of zero would have the pressure found at mean sea level, which is taken to be 101,325 Pa (14.696 psi; 29.921 inHg). In airliners , cabin altitude during flight is kept above sea level in order to reduce stress on the pressurized part of
12750-595: The same time, the Air Staff declared that the requirement for the transport to be capable of the same speed and altitude performance as the V-bombers was unnecessary. They also questioned the need to support the V bomber fleet at long distances, given the ever-shrinking state of the British Empire . These changes in attitude may have also been due to government pressure for the RAF to procure the turboprop-powered Bristol Britannia to equip Transport Command . During late 1955,
12875-441: The supersonic airliner Concorde had a particularly high pressure differential due to flying at unusually high altitude: up to 60,000 ft (18,288 m) while maintaining a cabin altitude of 6,000 ft (1,829 m). This increased airframe weight and saw the use of smaller cabin windows intended to slow the decompression rate if a depressurization event occurred. The Aloha Airlines Flight 243 incident in 1988, involving
13000-405: The total loss of the aircraft, passengers and crew grounded what was then the entire world jet airliner fleet. Extensive investigation and groundbreaking engineering analysis of the wreckage led to a number of very significant engineering advances that solved the basic problems of pressurized fuselage design at altitude. The critical problem proved to be a combination of an inadequate understanding of
13125-442: The use of composite airframes has aided the adoption of such comfort-maximizing practices. Pressurization becomes increasingly necessary at altitudes above 10,000 ft (3,048 m) above sea level to protect crew and passengers from the risk of a number of physiological problems caused by the low outside air pressure above that altitude. For private aircraft operating in the US, crew members are required to use oxygen masks if
13250-517: The vacuum of space, and also because an inert nitrogen mass must be carried. Care must also be taken to avoid decompression sickness when cosmonauts perform extravehicular activity , as current soft space suits are pressurized with pure oxygen at relatively low pressure in order to provide reasonable flexibility. By contrast, the United States used a pure oxygen atmosphere for its 1961 Mercury , 1965 Gemini , and 1967 Apollo spacecraft , mainly in order to avoid decompression sickness. Mercury used
13375-408: The war interrupted production. The 307's "pressure compartment was from the nose of the aircraft to a pressure bulkhead in the aft just forward of the horizontal stabilizer." World War II was a catalyst for aircraft development. Initially, the piston aircraft of World War II, though they often flew at very high altitudes, were not pressurized and relied on oxygen masks. This became impractical with
13500-412: The wings having been relocated to a low-mounted position, the addition of slotted flaps, and the overall size of the wing being considerably larger. As envisioned, the VC7 would not only be capable of flying the traditional Empire routes but also the increasingly prestigious North Atlantic market . In January 1953, Vickers received an order for the production of a flight-capable prototype, later given
13625-572: The world, carrying a mix of personnel and cargo needed for such deployments, while having similar speed and range capabilities to the bomber force. Vickers received a request from the MoS for submissions of the Valiant transport derivative. At the same time, the British Overseas Airways Corporation (BOAC) was also interested in a potential commercial airliner from Vickers; thus, the company was naturally excited that it would be possible to develop an aircraft that would serve as both
13750-399: The world. The better range that the VC7 offered took longer to address, and at one point was solved by incorporating the Conway into those designs. In mid-1955, it was acknowledged that the V-1000 would have a higher all-up weight of 248,000lb, instead of the 230,000lb figure that had been originally forecast, negatively impacting the aircraft's performance. By this time, political support for
13875-402: Was nationalised and became part of British Shipbuilders in 1977, was privatised as VSEL in 1986 and remains in operation to this day as BAE Systems Submarines . Meanwhile, the Naval Yard at High Walker on the River Tyne passed to Swan Hunter in 1968, was nationalised and became part of British Shipbuilders in 1977, was privatised still as Swan Hunter in 1986 but closed down during
14000-419: Was 2+2), providing more limited passenger capabilities than the VC7. Additionally, the VC7's wing design offered a number of advanced features and increased wing area that greatly reduced take-off run and allowed it to operate from a wider selection of airports, while at the same time offering longer ranges. When the US companies approached airlines with their plans, they found that they were constantly rejected as
14125-664: Was a British engineering conglomerate formed by the merger of the assets of Vickers Limited and Sir W G Armstrong Whitworth & Company in 1927. The majority of the company was nationalised in the 1960s and 1970s, with the remainder being divested as Vickers plc in 1977. It featured among Britain's most prominent armaments firms. Vickers merged with the Tyneside -based engineering company Armstrong Whitworth , founded by William Armstrong , to become Vickers-Armstrongs. Armstrong Whitworth and Vickers had developed along similar lines, expanding into various military sectors and produced
14250-449: Was another Vickers product. Military aircraft with the Vickers brand: Vickers also competed for contracts with designs such as: Vickers was a pioneer in producing airliners , early examples being converted from Vimy bombers. Post-WWII, Vickers went on to manufacture the piston-engined Vickers VC.1 Viking airliner, the Viscount and Vanguard turboprop airliners and (as part of BAC)
14375-626: Was bought by the then field engineers, and continues today as UK Calibrations Limited based in Kidderminster . The Vickers Stitcher was still being manufactured in India as recently as 2005. The steelmaking division became part of British Steel Corporation and the remaining interests were divested as the public company Vickers plc , whose various components were later split. The Vickers name ceased to exist in 2003 when Rolls-Royce renamed its acquisition Vinters Engineering . Vickers-Armstrongs inherited
14500-597: Was built at its Brooklands factory in Surrey although the former Supermarine and Vickers works continued to brand their products under their former names. In 1960 the aircraft interests were one of the founding companies merged to form BAC. The hovercraft activities of Vickers-Armstrongs were merged with those of the Westland Aircraft company (including those of Saunders-Roe ) to form the British Hovercraft Corporation in 1966 with Vickers holding 25% of
14625-451: Was closed in 1963 and the Vickers brand name for aircraft was dropped by BAC in 1965. Under the terms of the Aircraft and Shipbuilding Industries Act 1977 BAC was nationalised to become part of British Aerospace (later BAE Systems ). The Aircraft and Shipbuilding Industries Act also led to the nationalisation of Vickers' shipbuilding division as part of British Shipbuilders . This division
14750-553: Was designed by Garrett AiResearch Manufacturing Company , drawing in part on licensing of patents held by Boeing for the Stratoliner. Post-war piston airliners such as the Lockheed Constellation (1943) made the technology more common in civilian service. The piston-engined airliners generally relied on electrical compressors to provide pressurized cabin air. Engine supercharging and cabin pressurization enabled aircraft like
14875-522: Was internally designated as the VC7 . Working in direct cooperation with BOAC throughout the studies performed for the project, Vickers came to quickly recognise that producing a suitable aircraft would not be a straightforward matter of simply pairing the Valiant's wings onto a new fuselage suitable for transport duties. Amongst the changes required would be an entirely new structure, the adoption of roomy and pressurised cabin , and more powerful engines. RAF requirements also provided some complications for
15000-496: Was meant to power. As had been pointed out at the time, the VC7's performance from limited airfields was considerably better than that of the Boeing 707, which required long runways and extensive ground support. This limited the BOAC 707s to high-volume routes between larger well-equipped airports in Europe and North America. BOAC was also under strong political pressure to offer jet service on
15125-414: Was performed at Vickers' facility at Wisley Airfield , Surrey ; flight trials would have also been based there. By November 1956, over £4 million had been spent on the V-1000 project; the first prototype had also reached 80 per cent completion. It had been estimated that the VC7 would have been in operational service as early as 1959, the same year in which the first V-1000s were projected to be delivered to
15250-458: Was possible by releasing stored oxygen into the cockpit, which was released directly into an enclosed cabin and not to an oxygen mask, which was developed later. With this system flights nearing 40,000 ft (12,192 m) were possible, but the lack of atmospheric pressure at that altitude caused the pilot's heart to enlarge visibly, and many pilots reported health problems from such high altitude flights. Some early airliners had oxygen masks for
15375-554: Was privatised as Vickers Shipbuilding & Engineering in 1986, later passing to GEC as part of Marconi Marine and survives to this day as part of BAE Systems Submarines . Vickers Container and Packaging Machinery Division, including the Vickers Stitcher and Vickers Hardness Machine business, was bought by Fords Industrial Products, part of Barry Wehmiller in 1986. In 1991 the Vickers Hardness Machinery business
15500-634: Was the Vickers Higson . Vickers produced larger weapons such as the Ordnance QF 2-pounder gun used on tanks. In 1948 Vickers bought the Australian business of Charles Ruwolt Ltd for £750,000 following Ruwolt's death in 1946. During World War II Ruwolt's firm produced armaments for the Australian Government, including field artillery such as mortars and howitzer cannon. After the 1927 merger,
15625-439: Was to traverse the full length of the fuselage for strength and to stiffen the structure. The entirety of the fuselage was to be pressurised , including its two underfloor cargo holds; the only exceptions being far end of the tail and the landing gear bays. A total of eighteen semi-circular windows, similar to those used on the earlier Vickers Viscount , were to be set into the fuselage along with front and rear entrance doors and
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