The Short SA.4 Sperrin was a British jet bomber design of the early 1950s, built by Short Brothers and Harland of Belfast. It first flew in 1951. From the onset, the design had been viewed as a fall-back option in case the more advanced strategic bomber aircraft in development to equip the Royal Air Force's nuclear-armed V bomber force, experienced delays; as their usefulness as an interim bomber aircraft did not emerge, a pair of flying prototypes were instead used to gather research data on large jet aircraft and to support the development of other technologies, such as several models of jet engines. The two aircraft completed were retired in the late 1950s and scrapped sometime thereafter; the Air Ministry issued a specification on 11 August 1947 B.14/46 for a "medium-range bomber landplane" that could carry a "10,000 pound bomb to a target 1,500 nautical miles from a base which may be anywhere in the world", with the stipulation it should be simple enough to maintain at overseas bases. The exact requirements included a weight of 140,000 lb.
The B.35/46 specification required that the laden weight would be under 100,000 lb, the bomber have a cruising speed of 500 knots and that the service ceiling would be 50,000 ft. This request would become the foundation of the Royal Air Force's V bombers, Britain's airborne nuclear deterrent. At the same time, the British authorities felt there was a need for an independent strategic bombing capability—in other words that they should not be reliant upon the American Strategic Air Command. In late 1948, the Air Ministry issued their specification B.35/46 for an advanced jet bomber that would serve as a successor to the Avro Lincoln, the then-standard heavy aircraft of RAF Bomber Command, that it should be the equal of anything that either the Soviet Union or the Americans would have. The exact requirements included that the laden weight would be under 100,000 lb, the ability to fly to a target 1,500 nautical miles distant at 500 knots with a service ceiling of 50,000 ft and again that it should be simple enough to maintain at overseas bases.
A further stipulation that a nuclear bomb, weighing 10,000 lb and measuring 30 ft in length and 10 ft in diameter, could be accommodated. This request would be the foundation of the V bombers. However, the Air Ministry accepted that the requirement might prove to be difficult to achieve in the time-scale required and prepared for a fall-back position by re-drafting B.14/46 as an "insurance" specification against failure to speedily develop the more advanced types that evolved into the Vickers Valiant, Avro Vulcan and Handley Page Victor, as this was to be a less ambitious conventional type of aircraft, with un-swept wings and some sacrifice in performance. The only significant performance differences between B.14/46 and the more advanced B.35/46 were a lower speed of 435 knots and a lower height over the target of 35,000 to 45,000 ft. According to aviation authors Bill Gunston and Peter Gilchrist, the specification's ignorance of a swept wing was odd for the era, had been made in order to allow the prospective bomber to be delivered more quickly.
A total of four firms submitted tenders to meet the B.14/46 specification, Shorts' submission was selected as it had been judged to be superior. The selection of Shorts was "astonishing" according to Bill Gunston and Peter Gilchrist, noted that their submission, while being a sound design, had been subject to luck. Under this requirement, the Air Ministry placed a contract for two flying prototypes and a static airframe with Shorts; the design was known by the company designations of SA.4 and SA.4. As the Sperrin was considered to be a possible production aircraft early on, a decision was taken for the two prototypes to be constructed upon production jigs. Bill Gunston and Peter Gilchrist commented that, if a subsequent production order had been issued, an initial operational squadron could have been equipped by late 1953. Many design elements of the Sperrin had more in common with aircraft of the Second World War than those of the new jet age; the design was straightforward in most aspects, with the exceptions of the flight controls and the unusual engine arrangement: The engines were mounted in pairs in nacelles mid-wing, one engine being stacked above the other, for a total of four engines.
VX-158 had the distinction of being the first aircraft to receive production Rolls-Royce Avon engines. The airframe was built of light aluminium alloys, principally the 75ST alloy; the Sperrin employed a traditional straight wing, although the wing's fixed leading edge was swept and featured curved fillets at the junction with the engine nacelles. The trailing edge had simple flaps inboard of the nacelles and large ailerons outboard. Both the flaps and air brakes were operated hydraulically, an independent system for emergency actuation was present. Up to 6,170 imperial gallons of fuel could be
A trade fair is an exhibition organized so that companies in a specific industry can showcase and demonstrate their latest products and services, meet with industry partners and customers, study activities of rivals, examine recent market trends and opportunities. In contrast to consumer fairs, only some trade fairs are open to the public, while others can only be attended by company representatives and members of the press, therefore trade shows are classified as either "public" or "trade only". A few fairs are hybrids of the two, they are held on a continuing basis in all markets and attract companies from around the globe. For example, in the U. S. there are over 10,000 trade shows held every year, several online directories have been established to help organizers and marketers identify appropriate events. Modern trade fairs follow in the tradition of trade fairs established in late medieval Europe, in the era of merchant capitalism. In this era and craft producers visited towns for trading fairs, to sell and showcase products.
From the late eighteenth century, industrial exhibitions in Europe and North America became more common reflecting the technological dynamism of the Industrial Revolution. In the late 19th century, the concept of annual industry-wide trade shows gained traction, spreading from European manufacturing centers to North America. By the 20th century, specialized companies came into existence to manage the trade-show industry, permanent trade show grounds or convention centers were established as venues that featured a rotating calendar of trade shows. In the 21st century, with the rapid industrialization of Asia, trade shows and exhibitions are now commonplace throughout the Asian continent, with China dominating the exhibitions industry in Asia, accounting for more than 55 per cent of all space sold in the region in 2011. Trade fairs play important roles in marketing as well as business networking in market sectors that use them. People will seek to meet people and companies at their own level in the supply chain, as well as potential suppliers and potential buyers.
There will be a central trade show floor with booths where people exhibit their goods or services, throughout the day there will be seminars for continuing education on matters relevant to the industry, like best practices and regulation. There will be some shared meals with keynote speakers, social events in the evenings. Booths range from simple tables to elaborate constructions. Trade fairs involve a considerable investment in time and money by participating companies; the planning includes arranging meetings with other attendees beforehand and resources to follow up on opportunities that are created at the fair. Costs include space rental, booth design and construction of trade show displays, telecommunications, travel and promotional literature and items to give to attendees. In addition, costs are incurred at the show for services such as electrical, booth cleaning, internet services, drayage; this local spending on logistics leads cities to promote trade shows as a means of local economic development, as well as providing opportunities for local businesses to grow, attract new businesses to come.
Agricultural show Buyers Market of American Craft County fair Lead retrieval List of world's fairs Rodeo State fair World's fair Media related to Trade fairs at Wikimedia Commons Trade show at Encyclopædia Britannica
The Saunders-Roe SR. N5 was a medium-sized hovercraft which first flew in 1964, it has the distinction of being the first production-built hovercraft in the world. A total of 14 SR. N5s were constructed. While Sauders-Roe had developed and produced the type, an additional seven vehicles were manufactured by Bell Aerosystems under licence in the United States, designated as the Bell SK-5. A number of SK-5s were operated by the US military, this includes a number which became Patrol Air Cushion Vehicles, saw action in Vietnam; the SR. N5 was subsequently developed into "stretched" variant, designated as the SR. N6 and went on to be produced in greater numbers The first SR. N5 started sea trials in April 1964. At least two of the Bell-built SK-5s were placed into civilian service. San Francisco and Oakland Helicopter Airlines operated the SK-5 for scheduled passenger services in the San Francisco Bay Area during the mid 1960s as a supplement to its helicopter airline service. Four SR. N5s entered service with the Interservice Hovercraft Trials Unit at RNAS Lee-on-Solent for trials and operational missions.
Given the military aircraft serial numbers XT492, XT493, XT657 and XW246, these were deployed in the UK, Thailand, Aden and Belgium. Two were subsequently converted to SR. N6s. Vessel XT 492 is prominently featured in the final of the 1971 Dr. Three Bell SK-5s saw service with the United States Navy and another three with the United States Army in Vietnam during the late 1960s; the Sultanate of Brunei and the Canadian Coast Guard had one SR. N5 each
The Saunders-Roe SR. N6 hovercraft was a larger version of the earlier SR. N5 series, it incorporated several features that resulted in the type becoming the one of most produced and commercially successful hovercraft designs in the world. While the SR. N2 and SR. N5s operated in commercial service as trials craft, the SR. N6 has the distinction of being the first production hovercraft. In comparison to the SR. N5, the SR. N6 was stretched in length; some models of the craft were stretched further, enabling an greater capacity. Experience gained in the development of the SR. N6 has been attributed as contributing towards the design and production of the largest civil hovercraft to be produced, the SR. N4. Several major design features of the SR. N6 appeared on both the SR. N4 and further hovercraft designs by Saunders-Roe and its successor, the British Hovercraft Corporation. In late 1964, Saunders-Roe commenced design work on multiple hovercraft designs. N4 and studies into a prospective 2,000 ton freighter, there was interest in developing its existing smaller hovercraft range.
In particular, the firm had observed customer demand for a model of the SR. N5 that would be capable of carrying a much greater payload. According to Saunders-Roe's own projections, an increase of the craft's payload by 110 per cent would only reduce performance by 10 per cent as the increased payload was in part offset by the expanded cushion area, which meant that cushion pressure would not need to be increased instead; the first craft to be lengthened in this manner, in effect becoming the first SR. N6, was the ninth SR. N5 to have been produced. Following three months of work to adapt the craft to the new configuration, this first prototype was launched for the first time on 9 March 1965. Portions of the SR. N6's development were performed in conjunction with Hovertravel, a newly-formed operating company located near Sauders-Roe's East Cowes facility. In June 1965, following an initial series of trials, the SR. N6 prototype was delivered to operated by Scandinavian Hovercraft Promotions of Oslo, Norway under the name'Scanhover'.
The SR. N6 had been designed in such a fashion that it could be extended from its initial 36 seat capacity to 58 without having to perform a major redesign or incurring high building costs. Work on the stretched SR. N6 was headed by Ray Wheeler, the Chief Designer of the British Hovercraft Corporation - which Saunders-Roe had by merged into. Many components and systems remained unchanged, including the expensive Bristol Gnome turboshaft engine; the most substantial change on the stretched craft, beyond the increased length, was the adoption of a twin-propeller configuration, done in order to reduce tip speed and thus noise. Hovertravel produced their first stretched SR. N6, achieved with engineering support from the BHC, by converting an existing damaged SR. N6 and two SR. N5s; the Saunders-Roe SR. N6 is a medium-sized hovercraft designed for passenger service; the initial models of the type were capable of accommodating up to 38 passengers, greater than the maximum capacity of 18 that could be carried by the smaller SR.
N5. The SR. N6 was subsequently further stretched to accommodate a further 20 passengers. By increasing the capacity to 58 seats, the SR. N6 Mk.1S became the first hovercraft to be capable of transporting a typical coach load of people. In a military configuration, the SR. N6 is capable of carrying up to 55 equipped troops, or alternatively up to 6 tons of equipment; the SR. N6 was powered by a single marinised model of the Bristol Gnome turboshaft engine; the Gnome engine was an expensive component for operators, leading to some establishing their own internal overhaul facilities and making arrangements with other Gnome operators, including the Royal Navy, to reduce costs from relying on costly services from Rolls-Royce Limited. Around 20 per cent of the operating costs of the type have been attributed to maintenance of the 4 ft flexible skirt, which lasted for up to 500 hours, while similar cost levels have been reported for fuel. Early on, the SR. N6 was outfitted with an improved skirt, featuring fingers and forward puff ports, which resulted in improved forward control and reduced skirt wear.
The endurance of the fingers would be progressively improved over time, issues with salt spray negatively affecting both the engine and propeller were encountered early on. An initial experience of some components having short overhaul lifespans or being unreliable was encountered during early days. During the early years of not only the SR. N6 but other hovercraft as well, the hovercraft skirt remained an unresolved area of difficulty during this era; the SR. N6 was piloted from a forward-seated position at the front of the main passenger cabin; the pilot would exercise control over the direction of the craft via a series of control surfaces, located behind the variable pitch propeller. Early on, pilots were aviators whic
Handley Page Victor
The Handley Page Victor is a British jet-powered strategic bomber and produced by the Handley Page Aircraft Company, which served during the Cold War. It was the third and final V-bomber to be operated by the Royal Air Force, the other two being the Avro Vulcan and the Vickers Valiant; the Victor had been developed as part of the United Kingdom's airborne nuclear deterrent. In 1968, it was retired from the nuclear mission following the discovery of fatigue cracks, exacerbated by the RAF's adoption of a low-altitude flight profile to avoid interception. A number of Victors were modified for strategic reconnaissance, using a combination of radar and other sensors; as the nuclear deterrence mission was given to the Royal Navy's submarine-launched Polaris missiles in 1969, a large V-bomber fleet could not be justified. Many of the surviving Victors were converted into aerial refuelling tankers. During the Falklands War, Victor tankers were used in the airborne logistics operation to refuel Vulcan bombers on their way to and from the Black Buck raids.
The Victor was the last of the V-bombers to be retired, the final aircraft being removed from service on 15 October 1993. In its refuelling role, it was replaced by the Lockheed Tristar; the origin of the Victor and the other V bombers is linked with the early British atomic weapons programme and nuclear deterrent policies that developed in the aftermath of the Second World War. The atom bomb programme formally began with Air Staff Operational Requirement OR.1001 issued in August 1946, which anticipated a government decision in January 1947 to authorise research and development work on atomic weapons, the U. S. Atomic Energy Act of 1946 having prohibited exporting atomic knowledge to countries that had collaborated on the Manhattan Project. OR.1001 envisaged a weapon not to exceed 24 ft 2 in in length, 5 ft in diameter, 10,000 lb in weight, suitable for release from 20,000 ft to 50,000 ft. At the same time, the Air Ministry drew up requirements for bombers to replace the existing piston-engined heavy bombers such as the Avro Lancaster and the new Avro Lincoln which equipped RAF Bomber Command.
In January 1947, the Ministry of Supply distributed Specification B.35/46 to aviation companies to satisfy Air Staff Operational Requirement OR.229 for "a medium range bomber landplane capable of carrying one 10,000 lb bomb to a target 1,500 nautical miles from a base which may be anywhere in the world." A cruising speed of 500 knots at heights between 35,000 ft and 50,000 ft was specified. The maximum weight when loaded ought not to exceed 100,000 lb; the weapons load was to include a 10,000 lb "Special gravity bomb", or over shorter ranges 20,000 lb of conventional bombs. No defensive weapons were to be carried, the aircraft relying on its speed and altitude to avoid opposing fighters; the similar OR.230 required a "long range bomber" with a 2,000 nautical miles radius of action at a height of 50,000 ft, a cruise speed of 575 mph, a maximum weight of 200,000 lb when loaded. Responses to OR.230 were received from Short Brothers and Handley Page. As a result, realising that the majority of targets would not require such a long range, a less demanding specification for a medium-range bomber, Air Ministry Specification B.35/46 was issued.
This demanded the ability to carry the same 10,000 lb bomb-load to a target 1,500 nmi away at a height of 45,000–50,000 ft at a speed of 575 mph. The design proposed by Handley Page in response to B.35/46 was given the internal designation of HP.80. To achieve the required performance, Handley Page's aerodynamicist Dr. Gustav Lachmann and his deputy, Godfrey Lee developed a crescent-shaped swept wing for the HP.80. Aviation author Bill Gunston described the Victor's compound-sweep crescent wing as having been "undoubtedly the most efficient high-subsonic wing on any drawing board in 1947"; the sweep and chord of the wing decreased in three distinct steps from the root to the tip, to ensure a constant critical Mach number across the entire wing and a high cruise speed. The other parts of the aircraft which accelerate the flow, the nose and tail, were designed for the same critical mach number so the shape of the HP.80 had a constant critical mach number all over. Early work on the project included tailless aircraft designs, which would have used wing-tip vertical surfaces instead.
The profile and shaping of the crescent wing was subject to considerable fine-tuning and alterations throughout the early development stages to counter unfavourable pitching behaviour in flight. The HP.80 and Avro's Type 698 were chosen as the best two of the proposed designs to B.35/46, orders for two prototypes of each were placed. It was recognised, that there were many unknowns associated with both designs, an order was placed for Vickers' design, which became the Valiant. Although not meeting the requirements of the specification, the Valiant design posed little risk of failure and could therefore reach service earlier; the HP.80's crescent wing was tested on a ⅓-scale glider, the HP.87, a modified Supermarine Attacker, given the Handley Page H
The Saunders-Roe SR. N1 was the first practical hovercraft; the concept has its origins in the work of British engineer and inventor Christopher Cockerell, who succeeded in convincing figures within the services and industry, including those within British manufacturer Saunders-Roe. Research was at one point supported by the Ministry of Defence. In order to test the theories and overall concept, it was decided that the construction of a full-scale craft, designated as the SR. N1. On 11 June 1959, it performed its first flight in front of the public; the SR. N1 participated in the test programme for four years prior to its retirement, by which point it had served its purpose in validating the concept and further hovercraft had been developed. In less than four years following the SR. N1's maiden flight, multiple hovercrafts were being designed and produced by several companies in the United Kingdom, as well as in Japan by Mitsubishi Shipbuilding & Engineering under a license given by Westland Aircraft.
During the 1950s, British manufacturing firm Saunders-Roe was diversifying in various new fields and product lines. In particular, the firm held an intense interest in developing advanced watercraft, such as its commissioning of a two-year study into the potential production of nuclear submarines for freight delivery purposes and the development of an advanced amphibious beach survey vessel, known as WALRUS. During this time, British engineer and inventor Christopher Cockerell had been exploring his own concepts on how to produce more efficient fast-moving watercraft, involving multiple technologies such as inflatable air cushions, pump-jets and centrifugal fans. Having tested and found substance to his theories during the early 1950s, Cockerell proceeded to approach various aircraft companies and shipbuilders, but had difficult gaining their backing, in part due to a lack of understanding of the technologies involved. Undeterred, his work soon attracted the attention of Lord Mountbatten, the First Sea Lord of the Royal Navy, who arranged for a demonstration of his model to Admiralty representatives and patent officials in 1956.
One of the Admiralty observers, Ron Shaw, was impressed by the concept and provided valuable support. The work was classified as an official secret for over four years, but neither the Royal Air Force, Royal Navy, or British Army gave the project any serious interest. Shaw and Cockerell approached Saunders-Roe, who agreed to study the concept and produce a report on it if they were issued with a contract; this arrangement would be the foundation of a long-lasting partnership between Cockerell and Saunders-Roe to develop and sell this new form of transport. In August 1957, an initial contract to perform theoretical and experimental analysis of the concept was awarded to Saunders-Roe; the firm's chief of aerodynamic research, John Chaplin, promptly met with Cockerell and became enthusiastic about the project. Finding the existing experimental data and methodology to have been sound, Chaplin favourably reported back to the Saunder-Roe's chief engineer. Following a series of wind tunnel, tow tank, free-flight tests, alongside use of a new two-dimensional test rig as well as use of the original research, the firm published two reports in May 1958.
These reports confirmed the validity of Cockerell's theories and data in addition to noting the considerable potential of the hovercraft concept. While there was no expressed military need for such an aircraft, it was impossible for the Ministry of Defence to finance further development. On 17 April 1958, Cockerell had his first meeting with the NRDC to present his idea. On the following day, the NRDC board confirmed its decision to support the project, soon noting that it would be the organisation's biggest project to date; the NRDC promptly issued Saunders-Roe with a authorisation to proceed. In 1959, a specialised subsidiary of the NDRC, named Hovercraft Development Limited, for which Cockerell was appointed as technical director to handle the contract with Sauders-Roe and built up a patent portfolio. Although led by Chaplin, Cockerell had considerable involvement in the ongoing design process. Saunders-Roe determined that, in addition to more theoretical work, a test programme involving a large-scale radio-controlled model would be necessary to provide sufficient data to make progress, produced a proposal to this effect on 4 September 1958.
In October 1958, the second stage of the contract was awarded, enabling advanced research into the development of the proposed air cushion and the corresponding principles, such as intake design, directional stability, control. It was at this point that the first pair of manned models were proposed, of which Model A was selected to proceed with. Development of the craft was not straightforward, having posed several challenges and difficulties that needed to be overcome from the onset. Early on, one criticism of the Model A was that the single annular peripheral jet e