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96-415: Turbojet engines consist of a compressor at the front, a burner area, and then a turbine that powers the compressor. In order to reach worthwhile compression ratios , compressors consist of multiple "stages", each further compressing the air leaving the previous one. One common problem with early jet engines was the phenomenon of "surging" or compressor stall . Stalls could occur when the approaching airflow

192-417: A basis for the creation of Swiss . By preventing the complete collapse of Swissair, the other airline-related businesses of the group were likewise spared collapse. Following another federal repayable funding commitment of one billion francs, each of the 26 long-haul aircraft ( MD-11s and A330s ) and 26 medium-haul aircraft ( A321s , A320s and A319s ) were able to be transferred to Crossair / Swiss at

288-706: A bigger mismatch of flow areas/density changes and blade angles. Two approaches were followed: slowing the blade speeds at the front of the compressor by splitting it into two separately rotating parts (spools) or making stators variable on the first few stages as well as the inlet vanes. A disadvantage is significant mechanical complexity as each stator blade has to be independently rotated to the desired angles. Two spools need more bearings and turned out to be heavier. Bleed valves, two or three spools and variable stators are all used together on modern engines to cope with rotating stall during starts and at low speeds and to allow surge-free fast accelerations. Rolls-Royce considered

384-786: A company that initially used older Swissair aircraft to fly to holiday destinations. As the first European customer, Swissair bought the Douglas DC-7 C which enabled the company to provide non-stop flights to the United States. For shorter-range routes, the Convair Metropolitan was used. In 1957, the Far East was added to the route network. Direct flights to Tokyo had intermediate stops in Athens , Karachi , Bombay , Bangkok and Manila . That same year, Swissair helped Aristotle Onassis form

480-474: A compression ratio of 6.5 or lower. The petrol-paraffin engine version of the Ferguson TE20 tractor had a compression ratio of 4.5:1 for operation on tractor vaporising oil with an octane rating between 55 and 70. Motorsport engines often run on high-octane petrol and can therefore use higher compression ratios. For example, motorcycle racing engines can use compression ratios as high as 14.7:1, and it

576-555: A disc, made up the aft rotor assembly. The efflux from the turbojet expanded through the (inner) turbine annulus, thus providing power directly to the fan blades located in the outer annulus. A full-length cowl, an annular exhaust system and a bucket thrust-reverser were fitted for the Convair 990. The unique feature of the CJ805-23 was the transonic single stage fan. NACA had done significant research on multistage transonic compressors during

672-441: A dynamic compression ratio similar to an engine with lower compression but earlier intake valve closure. Swissair Swissair ( German : Schweizerische Luftverkehr-AG ; French : S.A. Suisse pour la Navigation Aérienne ) was the national airline of Switzerland between its founding in 1931 and bankruptcy in 2002. Swissair was formed from a merger between Balair and Ad Astra Aero . For most of its 71 years, it

768-414: A given mass of air–fuel mixture due to its higher thermal efficiency . This occurs because internal combustion engines are heat engines , and higher compression ratios permit the same combustion temperature to be reached with less fuel, while giving a longer expansion cycle, creating more mechanical power output and lowering the exhaust temperature. In petrol (gasoline) engines used in passenger cars for

864-616: A national referendum held on 6 December 1992, Swiss citizens rejected taking part in the European Economic Area (EEA). This referendum was a significant disservice to Swissair, an airline with a tiny domestic market: its planes were not allowed to take up passengers during intermediate landings in EEA countries (e.g., Zürich-Frankfurt-New York), and Swissair was not allowed to offer tickets for sections that fully lie in EEA member countries (e.g., Zürich-Frankfurt-Paris). See also freedoms of

960-557: A new version with a relatively short fan cowl and thrust reverser, compared to the full-length cowling on the 990. Rolls-Royce quickly built and tested an aft-fan demonstrator Avon to compete with the greater thrust and lower specific fuel consumption of the CJ805-23. In the end, the Caravelle was instead re-engined with the Pratt & Whitney JT8D turbofan. The CJ805 program was not a commercial success, and GE lost approximately $ 80 million on

1056-528: A powerful, lightweight design 2,000 lb lighter than its 2-shaft competitor for the B-58, the J57 engine, and GE began considering it as the basis for a high-power engine for commercial use. In 1952, Chapman Walker's design team at GE built a one-off prototype of a jet engine designed specifically for transatlantic airliners. It used a single-stage fan powered by the same turbine shaft as the main engine compressor, as opposed to

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1152-610: A quality airline and from the fact that the political neutrality of Switzerland allowed the company to fly to exotic and lucrative destinations in Africa, the Middle East, South America and the Far East. In geographic terms, the central position of Switzerland in Europe helped it generate revenue from transfer passengers. By the early 1970s, Swissair was becoming known as "the flying bank", appealing to

1248-487: A serious issue. There was already a lawsuit, by residents around Newark airport, concerning the noise from existing propeller-driven aircraft such as the Lockheed Super Constellation , Boeing Stratocruiser and Douglas DC-7 C. One way to reduce this problem is to mix cold air into the jet exhaust, which was accomplished on early engines with the addition of scalloped nozzles. This solution was also adopted for

1344-453: A similar pressure ratio for their JT-3D turbofan. Although not an overhung design, the CJ805-23 transonic fan did not require any inlet guide vanes. There was, however, a series of structural vanes to help support the fan casing. With additional changes, fuselage stretches, and the addition of anti-shock bodies , the new airliner emerged as the Convair 990. However, by this time the project had suffered several delays, allowing new versions of

1440-683: A wider European market. Finally, after deregulation, Swissair tried to expand beyond its home market; after the Alcazar project was cancelled, Swissair aimed to be a major force in European aviation. In the mid-1990s, Swissair initiated the disastrous "Hunter Strategy", a major expansion programme devised by the US consulting firm McKinsey & Co . Using this strategy, Swissair aimed to grow its market share by acquiring small airlines rather than entering into alliance agreements. Swissair decided to acquire 49.5 per cent of

1536-464: Is a polytropic value for the ratio of specific heats for the combustion gases at the temperatures present (this compensates for the temperature rise caused by compression, as well as heat lost to the cylinder) Under ideal (adiabatic) conditions, the ratio of specific heats would be 1.4, but a lower value, generally between 1.2 and 1.3 is used, since the amount of heat lost will vary among engines based on design, size and materials used. For example, if

1632-415: Is common to find motorcycles with compression ratios above 12.0:1 designed for 95 or higher octane fuel. Ethanol and methanol can take significantly higher compression ratios than gasoline. Racing engines burning methanol and ethanol fuel often have a compression ratio of 14:1 to 16:1. In a piston engine , the static compression ratio ( C R {\displaystyle \mathrm {CR} } )

1728-447: Is done to increase fuel efficiency while under varying loads. Variable compression engines allow the volume above the piston at top dead centre to be changed. Higher loads require lower ratios to increase power, while lower loads need higher ratios to increase efficiency, i.e. to lower fuel consumption. For automotive use this needs to be done as the engine is running in response to the load and driving demands. The 2019 Infiniti QX50

1824-457: Is the static compression ratio : the ratio of the volume of the cylinder when the piston is at the bottom of its stroke to that volume when the piston is at the top of its stroke . The dynamic compression ratio is a more advanced calculation which also takes into account gases entering and exiting the cylinder during the compression phase. A high compression ratio is desirable because it allows an engine to extract more mechanical energy from

1920-409: Is the first commercially available car that uses a variable compression ratio engine. The static compression ratio discussed above — calculated solely based on the cylinder and combustion chamber volumes — does not take into account any gases entering or exiting the cylinder during the compression phase. In most automotive engines, the intake valve closure (which seals the cylinder) takes place during

2016-518: Is the ratio between the volume of the cylinder and combustion chamber when the piston is at the bottom of its stroke , and the volume of the combustion chamber when the piston is at the top of its stroke . It is therefore calculated by the formula C R = V d + V c V c {\displaystyle \mathrm {CR} ={\frac {V_{d}+V_{c}}{V_{c}}}} where V d {\displaystyle V_{d}} can be estimated by

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2112-538: Is used. This can reduce efficiency or damage the engine if knock sensors are not present to modify the ignition timing. Diesel engines use higher compression ratios than petrol engines, because the lack of a spark plug means that the compression ratio must increase the temperature of the air in the cylinder sufficiently to ignite the diesel using compression ignition . Compression ratios are often between 14:1 and 23:1 for direct injection diesel engines, and between 18:1 and 23:1 for indirect injection diesel engines. At

2208-725: The Curtiss Condor beginning in 1934. Nelly Diener , the first flight attendant in Europe, became world-famous. She was killed after just 79 flights in a crash near Wurmlingen, Germany, on 27 July 1934. The cause of the crash was material fatigue . In 1936, Douglas DC-2s were acquired, and London was added to the route network. In 1937, the bigger Douglas DC-3 was bought. In the same year, both founding fathers died: Walter Mittelholzer died while mountaineering in Steiermark , Austria, and Balz Zimmermann succumbed to an infectious disease. On 27 August 1939, days before World War II broke out,

2304-685: The Magadino Plains in Ticino . Operations were suspended in August 1944, when a Swissair DC-2 was destroyed in Stuttgart during an American bombing raid. On 30 July 1945, Swissair was able to resume commercial aviation. In 1947, the rise of shareholder capital to SFr 20 million (equivalent to SFr 95.61 million or US$ 105.06 million in 2021) enabled long-haul flights to New York, South Africa, and South America with Douglas DC-4s . The modern Convair 240 ,

2400-477: The Pratt & Whitney designs that were using a separate power shaft to run the fan. The GE design proved to be difficult to start and operate and was not developed further. In 1955 Jack Parker took over GE's Aircraft Gas Turbine division. He hired Dixon Speas to begin interviewing executives at airlines to try to get a sense of the future market. Parker asked Speas to interview not the CEOs, but executives that might be

2496-401: The cylinder volume formula: V d = π 4 b 2 s {\displaystyle V_{d}={\tfrac {\pi }{4}}b^{2}s} where Because of the complex shape of V c {\displaystyle V_{c}} it is usually measured directly. This is often done by filling the cylinder with liquid and then measuring the volume of

2592-447: The 1950s. Using this data, GE decided to design and test a high-pressure ratio single stage transonic fan. Much to their amazement the unit more than met the design target, including that of high efficiency. A modified version of this research unit was subsequently incorporated into the CJ805-23 aft fan. With no experience of transonic fan design and little time available, Pratt & Whitney had to resort to using 2 fan stages to produce

2688-549: The CEO by the time GE was ready to enter the civilian jet engine market. Parker, Speas and Neil Burgess, who ran the J79 program, spent a month meeting with American Airlines , Delta , United , KLM , Swissair and SAS . The meetings demonstrated that those airlines that were flying propeller aircraft across the Atlantic were all looking to replace them with jets. Around the same time, Convair

2784-575: The CJ805. Several airlines asked Convair for a larger version of the 880 with potential transatlantic range. Such a design would be larger to hold more seating, as well as having to carry more fuel. To power it, a more powerful engine would be needed. By this time, the Rolls-Royce Conway was entering service, and the Pratt & Whitney JT3D was following close behind. These designs both had twin-spool compressors, as opposed to using variable stators, and

2880-713: The CV-990s during that time. Swissair was the second European airline to offer service to the People's Republic of China , introducing service to Beijing and Shanghai in 1975. In the same year, Swissair was the launch customer for the DC-9-51. In 1977, Swissair was the launch customer for the third DC-9 type, the DC-9-81 variant, now called the MD-80. Armin Baltensweiler had travelled to a meeting of

2976-554: The Czechoslovak operator CSA purchased a Ford Trimotor in 1930. The Orion was the fastest commercial aeroplane of its time and was put to use on the "Express Line", Zürich - Munich - Vienna . This led Lufthansa to ask Heinkel for a model that could top Orion's speed, leading to the Heinkel He 70 . The first trans-Alpine route was introduced in 1933: Zürich- Milan . For the first time in Europe, flight attendants were employed aboard

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3072-678: The DC-4 on transatlantic routes. In 1948, the airport in Dübendorf, which had served as the base of Swissair, was relocated to Zürich-Kloten. Military aviation continued in Dübendorf. The next year, Swissair plunged into a financial crisis due to a sudden devaluation of the British pound because fares, except for traffic to the United States, were calculated in British currency. At that time, traffic to England made up 40 per cent of Swissair's revenue. In June 1950, Walter Berchtold, manager of Swiss Federal Railways,

3168-514: The DC-8 and 707 to lock up major sales. In the end, Convair sold only 102 880s and 990s in total, losing $ 600 million on the program. There was only one other customer for the 805-23. In 1961, Sud Aviation approached GE to pitch them on the idea of adapting the Rolls-Royce Avon powered Caravelle to the 805-23, producing a flying technology showcase for both companies. For this role they introduced

3264-546: The French investments. For the first time, the board began to consider scenarios for phasing out its existing participation in other airlines as Swissair looked to withdraw from its foreign investments. In January 2001, Bruggisser was summarily dismissed. Moritz Suter, the founder of Crossair, was nominated as the new CEO of SAirLines and thus all Group airlines, including Swissair. After only 44 days in charge, Suter resigned. In March 2001, two studies by consultants were presented to

3360-678: The McDonnell-Douglas directorial board in St. Louis to convince them to further stretch the fuselage of the DC-9-51. Baltensweiler was called the "Father of the MD-80". In 1979, Swissair was the first company to order the Airbus A310 and the jumbo jet variant with a stretched upper deck, the Boeing 747-300 . Later on, the Fokker 100 short-range aircraft and the three-engined MD-11 were aircraft for which Swissair

3456-646: The SAirGroup were handed over to the liquidation firm of Jürg Hoss and ceased operations on 31 March 2002. Crossair was renamed Swiss International Air Lines , or Swiss for short, and took over Swissair's intercontinental routes on 1 April 2002, officially ending 71 years of Swissair service. An investigation by the Zurich branch of Ernst & Young into factors behind the grounding revealed that "...in contradiction to representations made by SAir Group, not just 14.5 million Swiss Francs, but around CHF50 million were available at

3552-693: The Swiss Federal Government. The final Swissair flight landed in Zürich from São Paulo on 1 April 2002. On 1 April 2002, a former regional subsidiary Crossair renamed itself Swiss International Air Lines and took over most of Swissair's routes, planes , and staff. Swissair Group still exists and has since been liquidated. Swiss International Air Lines was taken over by the German airline Lufthansa in 2005. On 26 March 1931, Swissair – Schweizerische Luftverkehr AG (English: Swissair – Swiss Air Transport )

3648-477: The US Pullman railway cars . Two adjacent seats were moved towards each other and formed a lower berth. The wall panel could be folded downward, forming the upper berth in which the other person could sleep. A year later, a tourist class cabin was introduced on intra-European flights. In 1953, Swissair, with the city of Basel , founded a charter company called Balair , reusing the name of one of its predecessors,

3744-418: The addition of a completely separate fan system at the rear of the engine, powered by a new turbine stage. The system was essentially a bolt-on extension to the existing design and had almost no effect on the operation of the original engine. Each turbine blade was an integral part of a "blucket", the outboard section of which was a fan rotor blade. Running freely on a stub shaft, a series of buckets, mounted on

3840-440: The air . Like other airlines based in smaller countries, Swissair was now under significant pressure. More and more national airlines have affiliated themselves with airline alliances to maintain a worldwide market presence. But to be interesting for American alliance partners, an airline must have a critical size in terms of passenger numbers. To meet that goal, in 1993, an alliance between Swissair, KLM, SAS, and Austrian Airlines

3936-472: The airspace over Germany and France was closed. Swissair was forced to suspend service to Amsterdam, Paris, and London. Two days later, the Swissair service was closed completely. Of 180 employees, 131 had to serve in the army. Despite the war, some routes were later re-introduced, such as Munich, Berlin , Rome , and Barcelona . In 1940, an invasion of Switzerland was feared, and Swissair moved their operations to

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4032-526: The bank's acronym, "UBS", as the United Bandits of Switzerland . Two large bridge loans from the Swiss government were required to finance the continuation of flight operations. This notwithstanding, with the resumption of flight service, it was necessary for flight crews to carry large sums of cash to purchase fuel at foreign airports. On 1 October 2001, Project "Phoenix" was announced, under which parts of

4128-761: The banks, with some hotels expelling the crew, and having them return home at their own expense. All tickets sold were voided. 4 October 2001 saw demonstrations by former Swissair employees before the UBS presentation held in Glattbrugg, and the following day saw demonstrations in Bern 's Federal Square. At around the same time, SAirGroup's stake in Crossair was sold to the Swiss banks UBS and Credit Suisse . Furthermore, Crossair took over various assets of former Swissair, including its employees, aircraft, and most European routes. Swissair and

4224-410: The board, which showed the financial difficulties of SAirGroup. At this point, the directors resigned, with only Mario Corti , the former CFO of Nestlé , remaining. From April to August 2001, the group's Moody's credit rating was gradually downgraded from A3 to B1 (it was downgraded further to B2 on September 18th). The buying spree created a major cash flow crisis for parent company SAirGroup and

4320-663: The company struggled with severe turbulence: a currency crisis, collective chaos, an air traffic controllers' strike, the October War and the first oil crisis were weathered without significant damage. In the same year, the regional representative of Swissair in Buenos Aires was kidnapped by the Montoneros . After 38 days in captivity, he was released after the payment of SFr12.35 million (equivalent to SFr29.69 million or US$ 32.63 million in 2021) ransom. The airline also phased out

4416-495: The company's disposal on the morning of October 2, 2001". The report further stated that "Without the administrative inadequacies connected with the release of an escrow account , an additional CHF 73 million would have been available. Thus, overall some CHF 123 million would have been available at SAirGroup, SAirLines and Swissair." Former Crossair executive André Dosé, who also served as the first CEO of successor airline Swiss International Air Lines , stated in 2004 that this meant

4512-441: The competing Douglas DC-8 and Boeing 707 was a higher cruise speed. This demanded more engine power from a lighter design, which naturally led to a design like the J79. To gain experience with the engine in a civil setting, GE equipped a Douglas RB-66 with the new engine and flew simulated civil aviation routes out of Edwards Air Force Base . As development progressed, the 707 began to enter service, and noise complaints became

4608-561: The compression phase (i.e. after bottom dead centre , BDC), which can cause some of the gases to be pushed back out through the intake valve. On the other hand, intake port tuning and scavenging can cause a greater amount of gas to be trapped in the cylinder than the static volume would suggest. The dynamic compression ratio accounts for these factors. The dynamic compression ratio is higher with more conservative intake camshaft timing (i.e. soon after BDC), and lower with more radical intake camshaft timing (i.e. later after BDC). Regardless,

4704-549: The cylinders. Engines using port fuel-injection typically run lower boost pressures and/or compression ratios than direct injected engines because port fuel injection causes the air–fuel mixture to be heated together, leading to detonation. Conversely, directly injected engines can run higher boost because heated air will not detonate without a fuel being present. Higher compression ratios can make gasoline (petrol) engines subject to engine knocking (also known as "detonation", "pre-ignition", or "pinging") if lower octane-rated fuel

4800-485: The desire to partner with Air France instead. During the European airline deregulation transition, Jeffrey Katz served as CEO of Swissair from 1997 to 2000, a period of increased fuel prices and industry overcapacity . In the summer of 2000, SAir's CEO Philippe Bruggisser came under public pressure as the press published the group's financial situation. Swissair and Sabena were each losing one million francs per day, and another million were lost every day at LTU and

4896-459: The dynamic compression ratio is always lower than the static compression ratio. Absolute cylinder pressure is used to calculate the dynamic compression ratio, using the following formula: P cylinder = P atmospheric × CR γ {\displaystyle P_{\text{cylinder}}=P_{\text{atmospheric}}\times {\text{CR}}^{\gamma }} where γ {\displaystyle \gamma }

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4992-462: The end of that year, kerosene prices had doubled , and fuel costs had increased from 12% to 16% of total costs. Swissair was the first to order the Airbus A310 designed with a two-man cockpit for more traffic-tight short distances and on shorter medium distances, and accepted options for 10 more units. Another Boeing 747 was ordered. Dublin was added to the route network as a new destination, but service to Beirut had to be discontinued in mid-July due to

5088-689: The end of the winter schedule of 2001/02. On Easter Monday, 1 April 2002, the last flight of Swissair, flight SR145 from São Paulo, landed in Zürich. A 71-year-long chapter of Swiss aviation history thus came to an end. Between 1931 and 2002, Swissair transported more than 260 million passengers. The SwissairGroup (the name change from SAirGroup to SwissairGroup was announced in 2001 but never officially implemented) still existed as 'SAirGroup in Nachlassstundung' ( German : Swissair in Administration ) for several years until all assets were liquidated, including

5184-594: The engine's problems. GE quickly gained a reputation for standing behind their products that endures to this day. The work on the 805 also had several spin-off products. Among them was another aft-fan design, the General Electric CF700 used in the Dassault Falcon 20 business jet, which was developed from the General Electric J85 in the same way as the J79 was adapted to the 805. Their fan technology

5280-579: The expense of the core business of Swissair: commercial aviation. Due to a 12-day global flight ban for the DC-10 imposed by the US Federal Aviation Administration after the crash of American Airlines Flight 191 on 25 May 1979, a sizable portion of the long-haul fleet was on the ground. On October 7, after landing in Athens, a DC-8 overran the runway and caught fire , killing 14 passengers. By

5376-468: The federal government, cantons, municipalities, the Swiss Federal Railways, and the Swiss postal services, took over 30.6% of the shares and enabled Swissair to get a credit of 15  million Swiss Francs to purchase the airline's first two Douglas DC-6 B airliners for delivery in 1951. By that act, Swissair became Switzerland's national flag carrier . The new pressurised aircraft was to replace

5472-545: The first European airline to do so, Swissair signed in 1989 a cooperation treaty with Delta Air Lines and Singapore Airlines to create the alliance "Global Excellence". In 1990, together with SAS, Austrian Airlines and Finnair , the "European Quality Alliance" was founded. The last alliance was later renamed "The Qualiflyer Group". Because of the weak economy, the Gulf War and its aftermath, and rising operational costs, many airlines lost money in 1990 and 1991. Additionally,

5568-459: The first Swissair plane with a pressurised cabin, was used for short and medium-range flights starting in late 1948. The first Swissair DC-4 flight to New York was routed via Shannon , Ireland, and Stephenville, Newfoundland , on 2 May 1947. However, it ended in Washington, D.C. , due to fog at New York's LaGuardia Airport . The total elapsed time was 20 hours and 55 minutes. The public, including

5664-511: The first morning flights. During the morning, fuel suppliers refused to fuel the waiting aircraft. At 15:45 CEST , CEO Mario Corti announced a cessation of flight operations due to the security risks caused by the crossing of the Flight Duty Regulations. This led to the cancellation of over 230 flights, and thousands of passengers, as well as flight crews, were stranded around the world. Flight crew corporate credit cards were blocked by

5760-530: The grey-blue ones of the Swiss Women's Army Corps , so Berchtold introduced ones in a modish marine blue. Swissair initiated a veritable fashion competition among European airlines. In 1952, the cabin layout on northern trans-Atlantic routes was changed to one with a first and a tourist (economy) class. The first-class cabin had comfortable chairs in which one could sleep, given the name "Slumberettes". Those sleeping chairs were soon succeeded by beds, modelled after

5856-424: The grounding was not necessary and that Swissair could have likely continued flying until the financing for a successor airline would have been finalized, a view he reiterated in a 2021 interview. In his 2004 statement, Dose voiced the view that Corti and then-CFO Jacqualyn Fouse had lost oversight of Swissair's finances, accounting for this mismatch in perception of available funds. Mario Corti vehemently rejected

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5952-430: The group sought a payment delay. The Swiss federal authorities were willing to pay back half of the loan, so they secured the continuation of service. 2 October 2001 saw an increased necessity for strong liquidity, as all suppliers insisted on cash payments of outstanding invoices following a request for payment delay announced the day before. The company's cash reserves filed on that day were barely sufficient to carry out

6048-434: The invention of special devices to make the compressor work. The compressor worked well near its maximum speed, known as "design", with a fixed area convergence from entry to exit to go with the design values of compression/density and with fixed blade angles set to give low pressure losses. At low speeds the much lower compression didn't squeeze the air enough to get through the now too-small exit. The velocity triangle combined

6144-674: The large hidden assets and the huge liquidity Swissair had. Second, "flying bank" was the designation for a corporate group that cared more about financial management than about flying aeroplanes. With the beginning of deregulation and liberalisation in the late 1970s, airlines felt growing financial pressure. In 1978, Moritz Suter founded a regional airline named Crossair , which put Swissair under additional stress. To counter these changes, Swissair invested their large financial reserves into takeovers and into flight-related trades like baggage handling, catering, aircraft maintenance, and duty-free stores. This strategy diversified economic risks at

6240-465: The lower end of 14:1, NOx emissions are reduced at a cost of more difficult cold-start. Mazda's Skyactiv-D , the first such commercial engine from 2013, used adaptive fuel injectors among other techniques to ease cold start. The compression ratio may be higher in engines running exclusively on liquefied petroleum gas (LPG or "propane autogas") or compressed natural gas , due to the higher octane rating of these fuels. Kerosene engines typically use

6336-437: The lower speed of the front, low-pressure, spool made it easy to power a fan. The problems RR and P&W had addressed with the two-spool system had been solved on the J79 with the variable stators, so in relative terms, the single compressor rotational speed was much faster than the low-pressure stage of these other engines. This meant it was not suitable for direct connection to a fan stage. Instead, GE solved this problem with

6432-530: The new Greek airline, Olympic Airways . While competitors first looked at turboprop aeroplanes to replace their piston-engined craft, Swissair introduced jet aeroplanes. Together with SAS, Swissair bought Douglas DC-8s , which were delivered beginning in 1960. For medium and short-range routes, the Sud Aviation Caravelle was purchased. The aircraft were maintained in concert with SAS, and manuals for operation and maintenance were co-written. Swissair

6528-466: The notion that Swissair and SAirGroup bank accounts together held more than 14 million Swiss francs in a public statement after the Ernst & Young report came out. On 5 October, commercial flights on most routes were gradually resumed thanks to a federal emergency loan of over CHF 450 million. This occurred, in part, to ensure Switzerland's continued accessibility as a business location and to establish

6624-438: The now too-slow entry air with the blade speed and gave a stalling angle. One common solution used on early engines, and widely used today, was to give the air extra escape holes to speed up the entry air, i.e. the use of "bleed air" which is allowed to escape from openings near the middle of the compressor stages and vented overboard. The bleed valves close as the engine RPM increases towards operational speeds. Another solution

6720-495: The older and smaller DC-9. In addition, modern, fuel-saving aircraft, such as five new Boeing 747s with extended upper decks and two DC-10-30s with a longer range, were ordered. With the connection of Zurich Airport to the national railway network, bus delivery services from Zürich were discontinued. Air passengers were already able to check their luggage at the rail station. The route network was expanded with service to Jakarta, but flights to Tehran and Baghdad had to be suspended after

6816-477: The ongoing liberalisation of the industry strengthened competition. Consequently, Swissair lost 99 million Swiss Francs in the first half-year and could not pay dividends to its shareholders. In 1991 and 1992, Swissair had to utilise financial reserves to cushion significant losses from the commercial aviation sector. On 1 January 1991, commercial aviation in Europe was completely liberalised, and existing capacities led to aggressive competition among airlines. In

6912-808: The outbreak of the Iran-Iraq war. By the end of 1980, Swissair was represented in 196 cities. New representations or points of sale were opened in Luxembourg, Ulm, Ottawa, Raleigh, Westchester, Valparaíso, Jubil, Sanaa, and Salisbury/Harare. Under the name Swissôtel , the hotels Président in Geneva, International in Zürich, Drake in New York, and Bellevue Palace in Bern were administratively combined. Regarding further liberalisation of Europe's airline market, Swissair focused more on commercial aviation and extended its partnerships. As

7008-403: The past 20 years, compression ratios have typically been between 8:1 and 12:1. Several production engines have used higher compression ratios, including: When forced induction (e.g. a turbocharger or supercharger ) is used, the compression ratio is often lower than naturally aspirated engines . This is due to the turbocharger or supercharger already having compressed the air before it enters

7104-533: The political turmoil in Lebanon. Swissair was able to outperform the competition in a year that experts deemed to be the worst in the history of civil aviation. In contrast to other airlines, which began to offer a second-tier executive class , the proven cabin division into first and economy classes was maintained. The short-haul fleet was renewed with the MD-81 (DC-9-81) introduction. This type of aircraft partially replaced

7200-412: The program with only a few hundred engines produced in total. In service, the design proved fragile, but these problems led to the program's ultimate success for the company. During the time they were talking to airline CEOs, in 1956 the company hired the former head of American Airlines' maintenance department, John Montgomery, to run the production lines. Montgomery gathered comments from the industry on

7296-407: The same year, the first Boeing 747-200 jumbo jet was acquired, and in the next year, the first McDonnell Douglas DC-10-30 followed. Both types shaped the long-haul fleet until the 1990s. Again, the specifications of both aircraft were developed in collaboration with SAS. Also in 1972, Switzerland introduced a prohibition of night flights, which led to the cessation of cheaper night fares. In 1973,

7392-468: The short and medium-range routes, and, after convincing Douglas , which soon merged with McDonnell Aircraft to create McDonnell Douglas , ultimately merged with Boeing , offered a stretched variant: the DC-9-32. For the first time, Swissair was the launch customer of an aircraft type. In 1971, Armin Baltensweiler took over as president of the directorial board and ran the enterprise for over two decades. In

7488-491: The state of the engine market, and found that many were complaining about the unreliability of the large piston engines then being used, notably the Wright R-3350 . Wright management refused to put more money into the program to improve the engine, leading to a serious backlash from the customers. Montgomery hired Walter Van Duyan away from Wright to set up GE's service department, and they provided excellent service in spite of

7584-424: The static compression ratio is 10:1, and the dynamic compression ratio is 7.5:1, a useful value for cylinder pressure would be 7.5 × atmospheric pressure, or 13.7  bar (relative to atmospheric pressure). The two corrections for dynamic compression ratio affect cylinder pressure in opposite directions, but not in equal strength. An engine with high static compression ratio and late intake valve closure will have

7680-417: The used liquid. Most engines use a fixed compression ratio, however a variable compression ratio engine is able to adjust the compression ratio while the engine is in operation. The first production engine with a variable compression ratio was introduced in 2019. Variable compression ratio is a technology to adjust the compression ratio of an internal combustion engine while the engine is in operation. This

7776-557: The variable stator idea in the 1940s, but abandoned it until using it in the 1980s on the V2500 engine. They began development of two-spool designs, a concept that was also selected by Pratt & Whitney . The variable stator path was only selected by GE after a year-long design study competition comparing two spools and several stages of variable stators with objectives of efficient performance at cruise Mach 0.9 and at Mach 2, increased thrust, reduced fuel consumption and weight. The J79 emerged as

7872-459: The very successful Italian charter airline Air Europe, the unprofitable Belgian flag carrier Sabena , and significant stakes in the carriers Air Liberté , AOM , Air Littoral , Volare , LOT , Turkish Airlines , South African Airways , Portugália and LTU , and planned to acquire stakes in Aer Lingus , Finnair , Malév , as well as Brazilian carriers TAM and Transbrasil . By mid-2000, it

7968-520: Was also used in the XV-5 Vertifan . Data from FAA Type Certificate Data Sheet, E-306 Data from [1] Related development Related lists Compression ratio The compression ratio is the ratio between the volume of the cylinder and combustion chamber in an internal combustion engine at their maximum and minimum values. A fundamental specification for such engines, it can be measured in two different ways. The simpler way

8064-470: Was canvassing US carriers and found demand for a smaller jet aircraft for medium-range domestic routes. They began development of what would become the 880, and approached Burgess to see if GE could develop a version of the J79 for this role. Burgess responded by quickly sketching a version of the J79 with the afterburner removed and replaced by a thrust reverser , giving them an estimated unit price of $ 125,000 per engine. The 880's primary sales feature over

8160-416: Was elected to the directorial board of Swissair and served as the director. In 1971, he created the corporate culture of Swissair. He grasped the importance of corporate image and corporate identity and after the example of BOAC 's " Speedbird ", he introduced the arrow-shaped Swissair logo. Giving flight personnel a distinct uniform was also an important move. At the time, flight attendants' uniforms resembled

8256-611: Was exacerbated by the environment caused by the September 11 attacks . Unable to make payments to creditors on its large debt, and with the refusal of UBS to extend its line of credit, on 2 October 2001 the entire Swissair fleet was abruptly grounded. Many blamed UBS for the fiasco, causing demonstrators to take to the streets with signs referring to UBS chairman Marcel Ospel as " Bin Ospel ", quoting al-Qaeda leader Osama bin Laden , and redefining

8352-434: Was first deemed "un-Swiss". In the first operational year, 64 people were employed, including ten pilots, seven radio operators, and eight mechanics. Their planes offered 85 seats, and operation was maintained only from March to October. The route network had a length of 4,203 kilometres (2,612 mi). On 17 April 1932, Swissair bought two Lockheed Orions , making them the second European airline to use American planes after

8448-403: Was founded through the fusion of the airlines Ad Astra Aero (founded in 1919) and Balair (1925). Balz Zimmermann and the Swiss aviation pioneer Walter Mittelholzer were the founding fathers. In contrast to other airlines, it did not receive support from the government. The name "Swissair" was the proposal of Dr Alphonse Ehinger, president of the directorial board of Balair, although "Swissair"

8544-434: Was not in-line with the aircraft inlet to the compressor or when the throttle was advanced too quickly. When engines had to be designed with pressure ratios greater than about 5, to meet demands for reduced fuel consumption, a new stalling phenomenon came to light, rotating stall. It occurred at low compressor speeds and caused blades in the first stage to break. This troublesome speed area is known as "off-design" and required

8640-559: Was one of the few companies to order the Convair 990 Coronado for its medium and long-range routes. Although the aircraft did not initially fulfil contractual specifications, they were liked by employees and customers. They operated on the airline's routes to South America, West Africa, and the Middle and Far East. 1966 saw the introduction of the Douglas DC-9 . That aircraft became the backbone of

8736-687: Was one of the major international airlines and known as the "Flying Bank" due to its financial stability, causing it to be regarded as a Swiss national symbol and icon. It was headquartered at Zurich Airport , Kloten . In 1997, the Swissair Group was renamed SAirGroup (although it was again renamed Swissair Group in 2001), with four subdivisions: SAirLines (to which Swissair, regional subsidiaries Crossair and Balair, and leasing subsidiary FlightLease belonged), SAirServices, SAirLogistics, and SAirRelations. Due to its so-called "Hunter Strategy" of expanding its market by acquiring smaller airlines, Swissair

8832-690: Was predicted that Swissair would lose between SFr3.25 billion (equivalent to SFr3.51 billion or US$ 3.86 billion in 2021) and SFr4.45 billion (equivalent to SFr4.81 billion or US$ 5.29 billion in 2021) over the next three fiscal years. The management, however, maintained classical restructuring, and the Board approved the reorganisation of LTU for approximately SFr500 million (equivalent to SFr540.41 million or US$ 593.86 million in 2021) . Also, there were plans to take over Alitalia . In October 1999, Delta Air Lines cancelled its transatlantic Atlantic Excellence alliance with Swissair and Sabena , citing

8928-434: Was proposed. This project bore the name " Alcazar " to create a single Central European airline. However, in various countries, this project was criticised. In Switzerland itself, it was thought that the huge financial assets were too precious to sacrifice to merge Swissair with the other airlines. In the late 1980s and early 1990s, Swissair tried to merge with Air France , Lufthansa , and British Airways to get access to

9024-485: Was suffering from over-expansion by the late 1990s. The crash of Swissair Flight 111 in 1998, which killed all 229 people on board, generated a costly lawsuit and negative publicity for the airline. After the economic downturn following the September 11 attacks , Swissair's assets dramatically lost value, grounding the already-troubled airline in October 2001. The airline was later revived and kept alive until 31 March 2002 by

9120-505: Was the launch customer. 1983 saw the replacement of the older DC-9s with MD-83s. Since the 1960s, Swissair has been a world leader in the development of cargo reservation systems (CRS). PARS and CARIDO were examples of systems enabling the booking of passenger seats and freight space. After the 1960s, air traffic increased quickly and allowed many airlines—many of which were quasi-monopolists on their routes—to yield high revenues. Swissair profited from its well-established reputation as

9216-551: Was the use of variable inlet vanes. The angle of incidence of the vanes at the front of the engine is changed to partially block the inlet area, which reduces the compression, and also angle the air onto the compressor blades to prevent stalling. This has the advantage of being more efficient than allowing valuable compressed air to escape, although fuel consumption at low speeds is relatively unimportant. Further increases in pressure ratio, demanded by government procurement agencies and commercial airlines for long-range aircraft, caused

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