146-599: The Airco DH.9A is a British single-engined light bomber that was designed and first used shortly before the end of the First World War . It was a development of the unsuccessful Airco DH.9 bomber, featuring a strengthened structure and, crucially, replacing the under-powered and unreliable inline 6-cylinder Siddeley Puma engine of the DH.9 with the American V-12 Liberty engine. Colloquially known as
292-645: A blue-water navy was vital for global power projection; Tirpitz had his books translated into German, while Wilhelm made them required reading for his advisors and senior military personnel. However, it was also an emotional decision, driven by Wilhelm's simultaneous admiration for the Royal Navy and desire to surpass it. Bismarck thought that the British would not interfere in Europe, as long as its maritime supremacy remained secure, but his dismissal in 1890 led to
438-592: A grenade at the Archduke's car and injured two of his aides. The other assassins were also unsuccessful. An hour later, as Ferdinand was returning from visiting the injured officers in hospital, his car took a wrong turn into a street where Gavrilo Princip was standing. He fired two pistol shots, fatally wounding Ferdinand and his wife Sophie . According to historian Zbyněk Zeman , in Vienna "the event almost failed to make any impression whatsoever. On 28 and 29 June,
584-540: A guerrilla warfare campaign and only surrendered two weeks after the armistice took effect in Europe. Before the war, Germany had attempted to use Indian nationalism and pan-Islamism to its advantage, a policy continued post-1914 by instigating uprisings in India , while the Niedermayer–Hentig Expedition urged Afghanistan to join the war on the side of Central Powers. However, contrary to British fears of
730-444: 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,
876-460: 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
1022-585: 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,
1168-408: A change in policy and an Anglo-German naval arms race began. Despite the vast sums spent by Tirpitz, the launch of HMS Dreadnought in 1906 gave the British a technological advantage. Ultimately, the race diverted huge resources into creating a German navy large enough to antagonise Britain, but not defeat it; in 1911, Chancellor Theobald von Bethmann Hollweg acknowledged defeat, leading to
1314-481: A decade later, particularly with the introduction of the British de Havilland Comet jetliner in 1949. However, two catastrophic failures in 1954 temporarily grounded 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
1460-613: A direct threat. The 1908–1909 Bosnian Crisis began when Austria annexed the former Ottoman territory of Bosnia and Herzegovina , which it had occupied since 1878. Timed to coincide with the Bulgarian Declaration of Independence from the Ottoman Empire, this unilateral action was denounced by the European powers, but accepted as there was no consensus on how to resolve the situation. Some historians see this as
1606-471: A gap between the German armies as they closed on Paris. The French army, reinforced by the British expeditionary corps, seized this opportunity to counter-attack and pushed the German army 40 to 80 km back. Both armies were then so exhausted that no decisive move could be implemented, so they settled in trenches, with the vain hope of breaking through as soon as they could build local superiority. In 1911,
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#17327914965591752-425: 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
1898-615: 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
2044-455: 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
2190-620: A maximum speed of 144 mph (232 km/h). The Soviet Union built large numbers of an unlicensed copy of the DH.9A, the R-1 . After the production of 20 DH.4 copies, followed by about 200 copies of the DH.9 powered by the Mercedes D.IV engine (also designated R-1) and a further 130 powered by the Siddeley Puma (designated R-2), a copy of the DH.9A powered by the M-5 engine, a Soviet copy of
2336-548: A possibility. This was accentuated by British and Russian support for France against Germany during the 1911 Agadir Crisis . German economic and industrial strength continued to expand rapidly post-1871. Backed by Wilhelm II, Admiral Alfred von Tirpitz sought to use this growth to build an Imperial German Navy , that could compete with the British Royal Navy . This policy was based on the work of US naval author Alfred Thayer Mahan , who argued that possession of
2482-552: 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
2628-834: A revolt in India, the outbreak of the war saw a reduction in nationalist activity. Leaders from the Indian National Congress and other groups believed support for the British war effort would hasten Indian Home Rule , a promise allegedly made explicit in 1917 by Edwin Montagu , the Secretary of State for India . In 1914, the British Indian Army was larger than the British Army itself, and between 1914 and 1918 an estimated 1.3 million Indian soldiers and labourers served in Europe, Africa, and
2774-465: 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
2920-516: A significant escalation, ending any chance of Austria cooperating with Russia in the Balkans, while also damaging diplomatic relations between Serbia and Italy. Tensions increased after the 1911–1912 Italo-Turkish War demonstrated Ottoman weakness and led to the formation of the Balkan League , an alliance of Serbia, Bulgaria, Montenegro , and Greece . The League quickly overran most of
3066-544: 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
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#17327914965593212-478: A war on two fronts; the Schlieffen Plan envisaged using 80% of the army to defeat France, then switching to Russia. Since this required them to move quickly, mobilization orders were issued that afternoon. Once the German ultimatum to Russia expired on the morning of 1 August, the two countries were at war. At a meeting on 29 July, the British cabinet had narrowly decided its obligations to Belgium under
3358-402: A weak Ottoman government, rather than an ambitious Slav power like Bulgaria . Russia had ambitions in northeastern Anatolia while its clients had overlapping claims in the Balkans. These competing interests divided Russian policy-makers and added to regional instability. Austrian statesmen viewed the Balkans as essential for the continued existence of their Empire and saw Serbian expansion as
3504-455: A whole, the Somme offensive led to an estimated 420,000 British casualties, along with 200,000 French and 500,000 Germans. The diseases that emerged in the trenches were a major killer on both sides. The living conditions led to disease and infection, such as trench foot , lice , typhus , trench fever , and the ' Spanish flu '. At the start of the war, German cruisers were scattered across
3650-414: 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 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
3796-413: Is kept above sea level in order to reduce stress on the pressurized part of 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
3942-508: Is known, however, that from 1908 to 1913, military spending by the six major European powers increased by over 50% in real terms. The years before 1914 were marked by a series of crises in the Balkans, as other powers sought to benefit from the Ottoman decline. While Pan-Slavic and Orthodox Russia considered itself the protector of Serbia and other Slav states, they preferred the strategically vital Bosporus straits to be controlled by
4088-404: 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
4234-484: 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
4380-574: The Schutzkorps was established, and carried out the persecution of Serbs. The assassination initiated the July Crisis, a month of diplomatic manoeuvring between Austria-Hungary, Germany, Russia, France and Britain. Believing that Serbian intelligence helped organise Franz Ferdinand's murder, Austrian officials wanted to use the opportunity to end their interference in Bosnia and saw war as
4526-641: The World War . In August 1914, the magazine The Independent wrote "This is the Great War. It names itself". In October 1914, the Canadian magazine Maclean's similarly wrote, "Some wars name themselves. This is the Great War." Contemporary Europeans also referred to it as " the war to end war " and it was also described as "the war to end all wars" due to their perception of its unparalleled scale, devastation, and loss of life. The first recorded use of
Airco DH.9A - Misplaced Pages Continue
4672-695: The Australian Naval and Military Expeditionary Force landed on the island of New Britain , then part of German New Guinea . On 28 October, the German cruiser SMS Emden sank the Russian cruiser Zhemchug in the Battle of Penang . Japan declared war on Germany before seizing territories in the Pacific, which later became the South Seas Mandate , as well as German Treaty ports on
4818-700: The Basmachi Revolt in central Asia. A single example, serial number F1010 , survives and is on display at the Royal Air Force Museum London . The aircraft was completed by Westland Aircraft in June 1918 and was one of 18 DH.9A's assigned to No. 110 Squadron RAF . It was the thirteenth aircraft, but was given the number "12A" because thirteen was thought unlucky . The squadron began flying bombing missions in September 1918, and on
4964-434: The Boeing 787 Dreamliner and the Airbus A350 XWB , feature reduced operating cabin altitudes as well as greater humidity levels; 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
5110-793: The Deutsche Luftfahrt Sammlung (Berlin Air Museum), one of the museum's substantial collection of World War 1 aircraft. In 1943, it was one of the museum's exhibits that was moved to Czarnikau (now Czarnkow in Poland) to save them from the Allied bombing of Berlin . The area was captured by Polish forces in March 1945 and F1010 eventually became part of the collection of the Polish Aviation Museum , although it
5256-732: 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
5402-783: The First World War (28 July 1914 – 11 November 1918), also known as the Great War , was a global conflict between two coalitions: the Allies (or Entente) and the Central Powers . Fighting took place mainly in Europe and the Middle East , as well as in parts of Africa and the Asia-Pacific , and in Europe was characterised by trench warfare ; the widespread use of artillery , machine guns, and chemical weapons (gas); and
5548-721: The Rüstungswende or 'armaments turning point', when he switched expenditure from the navy to the army. This decision was not driven by a reduction in political tensions but by German concern over Russia's quick recovery from its defeat in the Russo-Japanese War and subsequent 1905 Russian Revolution . Economic reforms led to a significant post-1908 expansion of railways and transportation infrastructure, particularly in its western border regions. Since Germany and Austria-Hungary relied on faster mobilisation to compensate for their numerical inferiority compared to Russia,
5694-776: The United States entered the war on the Allied side following Germany's resumption of unrestricted submarine warfare against Atlantic shipping. Later that year, the Bolsheviks seized power in the Russian October Revolution , and Soviet Russia signed an armistice with the Central Powers in December, followed by a separate peace in March 1918. That month, Germany launched an offensive in
5840-506: The cabin altitude . This is defined as the equivalent altitude above mean sea level having 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
5986-492: 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
Airco DH.9A - Misplaced Pages Continue
6132-487: The hydrophone and depth charges were introduced, destroyers could potentially successfully attack a submerged submarine. Convoys slowed the flow of supplies since ships had to wait as convoys were assembled; the solution was an extensive program of building new freighters. Troopships were too fast for the submarines and did not travel the North Atlantic in convoys. The U-boats sunk more than 5,000 Allied ships, at
6278-419: 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
6424-413: 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
6570-764: The tank . After the First Battle of the Marne in September 1914, Allied and German forces unsuccessfully tried to outflank each other, a series of manoeuvres later known as the " Race to the Sea ". By the end of 1914, the opposing forces confronted each other along an uninterrupted line of entrenched positions from the Channel to the Swiss border. Since the Germans were normally able to choose where to stand, they generally held
6716-586: The " White Army " against the Bolsheviks during the Russian Civil War . In September 1919, the RAF personnel were ordered to return home, leaving their aircraft behind. A squadron of DH.9As was deployed to Turkey in response to the Chanak Crisis in 1922, but did not engage in combat. The DH.9A was one of the key weapons used by Britain to manage the territories that were in its control following
6862-649: The "Ninak" (from the phonetic alphabet treatment of designation "nine-A"), it served on in large numbers for the Royal Air Force following the end of the war, both at home and overseas, where it was used for colonial policing in the Middle East, finally being retired in 1931. Over 2,400 examples of an unlicensed version, the Polikarpov R-1 , were built in the Soviet Union, the type serving as
7008-588: The 1839 Treaty of London did not require it to oppose a German invasion with military force; however, Prime Minister Asquith and his senior Cabinet ministers were already committed to supporting France, the Royal Navy had been mobilised, and public opinion was strongly in favour of intervention. On 31 July, Britain sent notes to Germany and France, asking them to respect Belgian neutrality; France pledged to do so, but Germany did not reply. Aware of German plans to attack through Belgium, French Commander-in-Chief Joseph Joffre asked his government for permission to cross
7154-563: The 1879 Dual Alliance , which became the Triple Alliance when Italy joined in 1882. For Bismarck, the purpose of these agreements was to isolate France by ensuring the three Empires resolve any disputes between themselves. In 1887, Bismarck set up the Reinsurance Treaty , a secret agreement between Germany and Russia to remain neutral if either were attacked by France or Austria-Hungary. For Bismarck, peace with Russia
7300-441: The 1913 Treaty of London , which had created an independent Albania while enlarging the territories of Bulgaria, Serbia, Montenegro and Greece. However, disputes between the victors sparked the 33-day Second Balkan War , when Bulgaria attacked Serbia and Greece on 16 June 1913; it was defeated, losing most of Macedonia to Serbia and Greece, and Southern Dobruja to Romania. The result was that even countries which benefited from
7446-400: The 25th, the crew of F1010 claimed the destruction of a German Fokker D.VII fighter. The aircraft's fourth and final combat mission was on 5 October when either flak damage or engine trouble forced a landing behind German lines. The aircraft was undamaged by the landing and the crew were taken prisoner. The aircraft remained in German hands after the war and in 1936 it was put on display at
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#17327914965597592-569: The Austrians and Serbs clashed at the battles of the Cer and Kolubara ; over the next two weeks, Austrian attacks were repulsed with heavy losses. As a result, Austria had to keep sizeable forces on the Serbian front, weakening their efforts against Russia. Serbia's victory against Austria-Hungary in the 1914 invasion has been called one of the major upset victories of the twentieth century. In 1915,
7738-646: The Austrians briefly occupied the Serbian capital, Belgrade . A Serbian counter-attack in the Battle of Kolubara succeeded in driving them from the country by the end of 1914. For the first 10 months of 1915, Austria-Hungary used most of its military reserves to fight Italy. German and Austro-Hungarian diplomats scored a coup by persuading Bulgaria to join the attack on Serbia. The Austro-Hungarian provinces of Slovenia , Croatia and Bosnia provided troops for Austria-Hungary. Montenegro allied itself with Serbia. Bulgaria declared war on Serbia on 14 October 1915 and joined in
7884-553: The Balkan Wars, such as Serbia and Greece, felt cheated of their "rightful gains", while for Austria it demonstrated the apparent indifference with which other powers viewed their concerns, including Germany. This complex mix of resentment, nationalism and insecurity helps explain why the pre-1914 Balkans became known as the " powder keg of Europe ". On 28 June 1914, Archduke Franz Ferdinand of Austria , heir presumptive to Emperor Franz Joseph I of Austria , visited Sarajevo ,
8030-404: The Central Powers. However, the pro-German King Constantine I dismissed the pro-Allied government of Eleftherios Venizelos before the Allied expeditionary force arrived. The Macedonian front was at first mostly static. French and Serbian forces retook limited areas of Macedonia by recapturing Bitola on 19 November 1916 following the costly Monastir offensive , which brought stabilisation of
8176-649: The Chinese Shandong peninsula at Tsingtao . After Vienna refused to withdraw its cruiser SMS Kaiserin Elisabeth from Tsingtao, Japan declared war on Austria-Hungary, and the ship was sunk in November 1914. Within a few months, Allied forces had seized all German territories in the Pacific, leaving only isolated commerce raiders and a few holdouts in New Guinea. Some of the first clashes of
8322-472: The DH.9A's Liberty, entered production in 1924. The Polikarpov R-4 was a modification of the R-1, with the engine lowered and moved forward by 140 mm (5.5 in) to improve both the forward visibility and the C.G position. The nose shape was improved by fairing and by installing a retractable ventral radiator. Overall length was increased by 389 mm (15.3 in). Landing legs were changed from wood to steel. Testing showed insufficient improvement over
8468-548: The German High Seas Fleet was confined to port. German U-boats attempted to cut the supply lines between North America and Britain. The nature of submarine warfare meant that attacks often came without warning, giving the crews of the merchant ships little hope of survival. The United States launched a protest, and Germany changed its rules of engagement. After the sinking of the passenger ship RMS Lusitania in 1915, Germany promised not to target passenger liners, while Britain armed its merchant ships, placing them beyond
8614-465: The German Army increased in size from 1908 to 1914, he changed the allocation of forces between the two wings to 70:30. He also considered Dutch neutrality essential for German trade and cancelled the incursion into the Netherlands, which meant any delays in Belgium threatened the viability of the plan. Historian Richard Holmes argues that these changes meant the right wing was not strong enough to achieve decisive success. The initial German advance in
8760-462: The German right wing would sweep through the Netherlands and Belgium , then swing south, encircling Paris and trapping the French army against the Swiss border. The plan's creator, Alfred von Schlieffen , head of the German General Staff from 1891 to 1906, estimated that this would take six weeks, after which the German army would transfer to the East and defeat the Russians. The plan was substantially modified by his successor, Helmuth von Moltke
8906-426: The Germans bled heavily as well, with anywhere from 700,000 to 975,000 casualties between the two combatants. Verdun became a symbol of French determination and self-sacrifice. The Battle of the Somme was an Anglo-French offensive from July to November 1916. The opening day on 1 July 1916 was the bloodiest single day in the history of the British Army , which suffered 57,500 casualties, including 19,200 dead. As
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#17327914965599052-565: The Middle East. In all, 140,000 soldiers served on the Western Front and nearly 700,000 in the Middle East, with 47,746 killed and 65,126 wounded. The suffering engendered by the war, as well as the failure of the British government to grant self-government to India afterward, bred disillusionment, resulting in the campaign for full independence led by Mahatma Gandhi . Pre-war military tactics that had emphasised open warfare and individual riflemen proved obsolete when confronted with conditions prevailing in 1914. Technological advances allowed
9198-703: The Ottoman Empire , which disturbed the long-standing balance of power in Europe, as well as economic competition between nations triggered by industrialisation and imperialism . Growing tensions between the great powers and in the Balkans reached a breaking point on 28 June 1914, when a Bosnian Serb named Gavrilo Princip assassinated Archduke Franz Ferdinand , heir to the Austro-Hungarian throne. Austria-Hungary held Serbia responsible, and declared war on 28 July. After Russia mobilised in Serbia's defence, Germany declared war on Russia and France , who had an alliance . The United Kingdom entered after Germany invaded Belgium , whose neutrality it guaranteed, and
9344-545: The Ottomans joined the Central Powers in November. Germany's strategy in 1914 was to quickly defeat France, then to transfer its forces to the east, but its advance was halted in September , and by the end of the year the Western Front consisted of a continuous line of trenches stretching from the English Channel to Switzerland. The Eastern Front was more dynamic, but neither side gained a decisive advantage, despite costly offensives. Italy , Bulgaria , Romania , Greece and others joined in from 1915 onward. In April 1917,
9490-449: The Ottomans' territory in the Balkans during the 1912–1913 First Balkan War , much to the surprise of outside observers. The Serbian capture of ports on the Adriatic resulted in partial Austrian mobilisation, starting on 21 November 1912, including units along the Russian border in Galicia . The Russian government decided not to mobilise in response, unprepared to precipitate a war. The Great Powers sought to re-assert control through
9636-421: The R-1 to justify production but late R-1s incorporated some of the modifications. The United States also planned to adopt the DH.9A as a replacement for the DH.4. Development work on the Americanization of the aircraft commenced at McCook Field in Dayton, Ohio . Modifications included a new fuel system with increased fuel capacity, revised wings and tail surfaces, and replacement of the Vickers machine gun on
9782-549: The Russian Stavka agreed with the French to attack Germany within fifteen days of mobilisation, ten days before the Germans had anticipated, although it meant the two Russian armies that entered East Prussia on 17 August did so without many of their support elements. By the end of 1914, German troops held strong defensive positions inside France, controlled the bulk of France's domestic coalfields, and inflicted 230,000 more casualties than it lost itself. However, communications problems and questionable command decisions cost Germany
9928-429: The Serbian retreat toward the Adriatic coast in the Battle of Mojkovac on 6–7 January 1916, but ultimately the Austrians also conquered Montenegro. The surviving Serbian soldiers were evacuated to Greece. After the conquest, Serbia was divided between Austro-Hungary and Bulgaria. In late 1915, a Franco-British force landed at Salonica in Greece to offer assistance and to pressure its government to declare war against
10074-455: The West was very successful. By the end of August, the Allied left, which included the British Expeditionary Force (BEF), was in full retreat , and the French offensive in Alsace-Lorraine was a disastrous failure, with casualties exceeding 260,000. German planning provided broad strategic instructions while allowing army commanders considerable freedom in carrying them out at the front, but von Kluck used this freedom to disobey orders, opening
10220-399: The Western Front before the Armistice, with 99 Squadron (also serving with the Independent Air Force) replacing DH.9s, while 18 Squadron and 216 Squadron replaced DH.4s. Despite the superior performance of the DH.9A over the DH.9, the DH.9A squadrons suffered high losses during their long range bombing missions over Germany. Other squadrons flew coastal patrols from Great Yarmouth before
10366-430: The Younger . Under Schlieffen, 85% of German forces in the west were assigned to the right wing, with the remainder holding along the frontier. By keeping his left-wing deliberately weak, he hoped to lure the French into an offensive into the "lost provinces" of Alsace-Lorraine , which was the strategy envisaged by their Plan XVII . However, Moltke grew concerned that the French might push too hard on his left flank and as
10512-554: The aggressor, German Chancellor Bethmann Hollweg delayed the commencement of war preparations until 31 July. That afternoon, the Russian government were handed a note requiring them to "cease all war measures against Germany and Austria-Hungary" within 12 hours. A further German demand for neutrality was refused by the French who ordered general mobilization but delayed declaring war. The German General Staff had long assumed they faced
10658-453: The aircraft is cruising at its maximum altitude and then reduced gradually during descent until 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,
10804-511: The aircraft were forced down in the desert, the DH.9A's struggling under ever heavier loads. Despite this the aircraft served successfully, with the Liberty engine being picked out for particular praise for its reliability ("as good as any Rolls Royce") in such harsh conditions. Some DH.9A aircraft were also transported to India to supplement the British Indian Army . At home, the DH.9A continued on in regular RAF service until 1930, also forming
10950-496: 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
11096-474: The attack by the Austro-Hungarian army under Mackensen's army of 250,000 that was already underway. Serbia was conquered in a little more than a month, as the Central Powers, now including Bulgaria, sent in 600,000 troops in total. The Serbian army, fighting on two fronts and facing certain defeat, retreated into northern Albania . The Serbs suffered defeat in the Battle of Kosovo . Montenegro covered
11242-543: The best way of achieving this. However, the Foreign Ministry had no solid proof of Serbian involvement. On 23 July, Austria delivered an ultimatum to Serbia, listing ten demands made intentionally unacceptable to provide an excuse for starting hostilities. Serbia ordered general mobilization on 25 July, but accepted all the terms, except for those empowering Austrian representatives to suppress "subversive elements" inside Serbia, and take part in
11388-455: 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
11534-483: The border and pre-empt such a move. To avoid violating Belgian neutrality, he was told any advance could come only after a German invasion. Instead, the French cabinet ordered its Army to withdraw 10 km behind the German frontier, to avoid provoking war. On 2 August, Germany occupied Luxembourg and exchanged fire with French units when German patrols entered French territory; on 3 August, they declared war on France and demanded free passage across Belgium, which
11680-487: The cabin altitude may not exceed this limit at 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
11826-422: The cabin altitude must be maintained at 8,000 ft (2,438 m) or less. Pressurization of 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
11972-420: 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
12118-478: 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
12264-600: The campaign saw the first use of anti-aircraft warfare after an Austrian plane was shot down with ground-to-air fire, as well as the first medical evacuation by the Serbian army. Upon mobilisation, in accordance with the Schlieffen Plan , 80% of the German Army was located on the Western Front, with the remainder acting as a screening force in the East. Rather than a direct attack across their shared frontier,
12410-649: The capital of the recently annexed Bosnia and Herzegovina . Cvjetko Popović , Gavrilo Princip , Nedeljko Čabrinović , Trifko Grabež , Vaso Čubrilović ( Bosnian Serbs ) and Muhamed Mehmedbašić (from the Bosniaks community), from the movement known as Young Bosnia , took up positions along the Archduke's motorcade route, to assassinate him. Supplied with arms by extremists within the Serbian Black Hand intelligence organisation, they hoped his death would free Bosnia from Austrian rule. Čabrinović threw
12556-466: The chance of a decisive outcome, while it had failed to achieve the primary objective of avoiding a long, two-front war. As was apparent to several German leaders, this amounted to a strategic defeat; shortly after the First Battle of the Marne , Crown Prince Wilhelm told an American reporter "We have lost the war. It will go on for a long time but lost it is already." On 30 August 1914, New Zealand occupied German Samoa (now Samoa ). On 11 September,
12702-466: 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
12848-462: The collapse of the Ottoman Empire following the Great War. Five squadrons of DH.9As served in the Middle East, occasionally carrying out bombing raids against rebellious tribesmen and villages. An additional radiator was fitted under the fuselage to cope with the high temperatures, while additional water containers and spares (including spare wheels lashed to the fuselage) were carried in case
12994-448: 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
13140-520: The cost of 199 submarines. World War I also saw the first use of aircraft carriers in combat, with HMS Furious launching Sopwith Camels in a successful raid against the Zeppelin hangars at Tondern in July 1918, as well as blimps for antisubmarine patrol. Faced with Russia in the east, Austria-Hungary could spare only one-third of its army to attack Serbia. After suffering heavy losses,
13286-522: The creation of new independent states, including Poland , Finland , the Baltic states , Czechoslovakia , and Yugoslavia . The League of Nations was established to maintain world peace, but its failure to manage instability during the interwar period contributed to the outbreak of World War II in 1939. Before World War II , the events of 1914–1918 were generally known as the Great War or simply
13432-449: The creation of strong defensive systems largely impervious to massed infantry advances, such as barbed wire , machine guns and above all far more powerful artillery , which dominated the battlefield and made crossing open ground extremely difficult. Both sides struggled to develop tactics for breaching entrenched positions without heavy casualties. In time, technology enabled the production of new offensive weapons, such as gas warfare and
13578-965: The crowds listened to music and drank wine, as if nothing had happened." Nevertheless, the impact of the murder of the heir to the throne was significant, and has been described by historian Christopher Clark as a "9/11 effect, a terrorist event charged with historic meaning, transforming the political chemistry in Vienna". Austro-Hungarian authorities encouraged subsequent anti-Serb riots in Sarajevo . Violent actions against ethnic Serbs were also organised outside Sarajevo, in other cities in Austro-Hungarian-controlled Bosnia and Herzegovina, Croatia and Slovenia. Austro-Hungarian authorities in Bosnia and Herzegovina imprisoned approximately 5,500 prominent Serbs, 700 to 2,200 of whom died in prison. A further 460 Serbs were sentenced to death. A predominantly Bosniak special militia known as
13724-507: 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
13870-543: 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
14016-472: 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
14162-578: The end of the year. The United States Marine Corps Northern Bombing Group received at least 53 DH-9As, and commenced operations in September 1918. While the squadrons in service at the end of the First World War quickly disbanded or re-equipped in the postwar dis-armament, the DH.9A continued in service as the RAF's standard light bomber, with 24 squadrons being equipped between 1920 and 1931, both at home and abroad. The first post war operations were in southern Russia during 1919, in support of
14308-531: 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
14454-472: 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, 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
14600-420: 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
14746-405: The existing aircraft were subject to a programme of refurbishment, a number of small contracts were placed for new production of DH.9As in 1925–26. These contracts resulted in a further 268 DH.9As being built. The new production and refurbished aircraft included batches of dual control trainers , as well as six aircraft powered by 465 hp (347 kW) Napier Lion engines, which were capable of
14892-695: The expansion of the French colonial empire . In 1873, Bismarck negotiated the League of the Three Emperors , which included Austria-Hungary , Russia and Germany. After the 1877–1878 Russo-Turkish War , the League was dissolved due to Austrian concerns over the expansion of Russian influence in the Balkans , an area they considered to be of vital strategic interest. Germany and Austria-Hungary then formed
15038-446: The first Liberty-engined DH.9A flying on 19 April 1918, and deliveries to the Royal Air Force starting in June. By the end of the war, a total of 2,250 DH.9As had been ordered, with 885 being built by the end of the year. As it was decided that the DH.9A would be a standard type in the postwar RAF, the majority of outstanding orders were fulfilled, with 1,730 being built under the wartime contracts before production ceased in 1919. While
15184-400: The first time on the Western Front. Several types of gas soon became widely used by both sides and though it never proved a decisive, battle-winning weapon, it became one of the most feared and best-remembered horrors of the war. In February 1916, the Germans attacked French defensive positions at the Battle of Verdun , lasting until December 1916. Casualties were greater for the French, but
15330-595: The front. Serbian and French troops finally made a breakthrough in September 1918 in the Vardar offensive , after most German and Austro-Hungarian troops had been withdrawn. The Bulgarians were defeated at the Battle of Dobro Pole , and by 25 September British and French troops had crossed the border into Bulgaria proper as the Bulgarian army collapsed. Bulgaria capitulated four days later, on 29 September 1918. The German high command responded by despatching troops to hold
15476-471: 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
15622-542: The globe, some of which were subsequently used to attack Allied merchant shipping . These were systematically hunted down by the Royal Navy, though not before causing considerable damage. One of the most successful was the SMS ; Emden , part of the German East Asia Squadron stationed at Qingdao , which seized or sank 15 merchantmen, a Russian cruiser and a French destroyer. Most of the squadron
15768-549: The high ground, while their trenches tended to be better built; those constructed by the French and English were initially considered "temporary", only needed until an offensive would destroy the German defences. Both sides tried to break the stalemate using scientific and technological advances. On 22 April 1915, at the Second Battle of Ypres , the Germans (violating the Hague Convention ) used chlorine gas for
15914-908: The initial equipment of the Royal Auxiliary Air Force (RAuxAF). The R-1 and R-2 were heavily used by the Soviet Air Forces through the 1920s as its standard light bomber and reconnaissance aircraft. The Soviets deployed them in support of the Chinese Kuomintang forces in the Northern Expedition against warlords in 1926–27, and against Chinese forces for control of the Chinese Eastern Railway in Manchuria in 1929. R-1s and R-2s were also used in support of operations during
16060-435: The introductions of tanks and aircraft . World War I was one of the deadliest conflicts in history , resulting in an estimated 10 million military dead and more than 20 million wounded , plus some 10 million civilian dead from causes including genocide . The movement of large numbers of people was a major factor in the deadly Spanish flu pandemic. The causes of World War I included the rise of Germany and decline of
16206-470: The investigation and trial of Serbians linked to the assassination. Claiming this amounted to rejection, Austria broke off diplomatic relations and ordered partial mobilisation the next day; on 28 July, they declared war on Serbia and began shelling Belgrade . Russia ordered general mobilization in support of Serbia on 30 July. Anxious to ensure backing from the SPD political opposition by presenting Russia as
16352-432: The line, but these forces were too weak to re-establish a front. Cabin pressurization Cabin pressurization 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
16498-538: The low outside air pressure above that altitude. For private aircraft operating in the US, crew members are required to use oxygen masks if 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,
16644-461: 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
16790-628: 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
16936-421: 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
17082-509: The new American 400 hp (300 kW) Liberty engine was chosen instead. As Airco was busy developing the Airco DH.10 Amiens twin-engined bomber, detailed design was carried out by Westland Aircraft . The DH.9 was fitted with new, longer-span wings and a strengthened fuselage structure. The first prototype flew in March 1918, powered by a Rolls-Royce Eagle as no Liberty engines were yet available. The prototype proved successful, with
17228-465: The ocean, even to neutral ships. Since there was limited response to this tactic, Germany expected a similar response to its unrestricted submarine warfare. The Battle of Jutland in May/June 1916 was the only full-scale clash of battleships during the war, and one of the largest in history. The clash was indecisive, though the Germans inflicted more damage than they received; thereafter the bulk of
17374-414: 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;
17520-528: 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
17666-440: 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
17812-429: 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
17958-421: The port side of the British built aircraft with a Browning machine gun on the starboard side. Plans called for Curtiss to build 4,000 modified aircraft, designated USD-9A . This order was cancelled with the end of the war and only nine were built by McCook Field and Dayton-Wright . One McCook aircraft was additionally modified with an enclosed, pressurised cockpit . In 1921, test pilot Lt. Harold R. Harris made
18104-457: 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
18250-499: 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
18396-399: 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),
18542-738: The protection of the " cruiser rules ", which demanded warning and movement of crews to "a place of safety" (a standard that lifeboats did not meet). Finally, in early 1917, Germany adopted a policy of unrestricted submarine warfare , realising the Americans would eventually enter the war. Germany sought to strangle Allied sea lanes before the United States could transport a large army overseas, but, after initial successes, eventually failed to do so. The U-boat threat lessened in 1917, when merchant ships began travelling in convoys , escorted by destroyers . This tactic made it difficult for U-boats to find targets, which significantly lessened losses; after
18688-410: 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
18834-478: The standard Soviet light bomber and reconnaissance aircraft through the 1920s. The DH.9A was planned as an improved version of the existing Airco DH.9 . The DH.9 was a disappointment owing to its under-performing and unreliable engines, and the DH.9A was to use a more powerful engine to resolve this. As the Rolls-Royce Eagle engine used in the successful DH.4 was unavailable in sufficient quantities,
18980-469: The term First World War was in September 1914 by German biologist and philosopher Ernst Haeckel who stated, "There is no doubt that the course and character of the feared 'European War' ... will become the first world war in the full sense of the word." For much of the 19th century, the major European powers maintained a tenuous balance of power , known as the Concert of Europe . After 1848, this
19126-691: The threat posed by the closing of this gap was more important than competing with the Royal Navy. After Germany expanded its standing army by 170,000 troops in 1913, France extended compulsory military service from two to three years; similar measures were taken by the Balkan powers and Italy, which led to increased expenditure by the Ottomans and Austria-Hungary. Absolute figures are difficult to calculate due to differences in categorising expenditure since they often omit civilian infrastructure projects like railways which had logistical importance and military use. It
19272-405: 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
19418-486: 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 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
19564-517: 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
19710-590: The war ended with the Armistice of 11 November 1918 . The Paris Peace Conference of 1919–1920 imposed settlements on the defeated powers, most notably the Treaty of Versailles , by which Germany lost significant territories, was disarmed, and was required to pay large war reparations to the Allies. The dissolution of the Russian, German, Austro-Hungarian, and Ottoman Empires redrew national boundaries and resulted in
19856-408: 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
20002-601: The war involved British, French, and German colonial forces in Africa. On 6–7 August, French and British troops invaded the German protectorates of Togoland and Kamerun . On 10 August, German forces in South-West Africa attacked South Africa; sporadic and fierce fighting continued for the rest of the war. The German colonial forces in German East Africa , led by Colonel Paul von Lettow-Vorbeck , fought
20148-418: The west , which despite initial successes left the German Army exhausted and demoralised. A successful Allied counter-offensive from August 1918 caused a collapse of the German front line. By early November, Bulgaria, the Ottoman Empire and Austria-Hungary had each signed armistices with the Allies, leaving Germany isolated. Facing a revolution at home , Kaiser Wilhelm II abdicated on 9 November, and
20294-523: The world's first high-altitude flight in a pressurised aircraft in the USD-9A at McCook Field in Dayton, Ohio. The DH.9A entered service in July 1918 with No. 110 Squadron RAF , moving to France on 31 August 1918 to serve with the RAF's Independent Air Force on strategic bombing missions. Its first mission was against a German airfield on 14 September 1918. A further three squadrons commenced operations over
20440-403: Was challenged by Britain's withdrawal into so-called splendid isolation , the decline of the Ottoman Empire , New Imperialism , and the rise of Prussia under Otto von Bismarck . Victory in the 1870–1871 Franco-Prussian War allowed Bismarck to consolidate a German Empire . Post-1871, the primary aim of French policy was to avenge this defeat, but by the early 1890s, this had switched to
20586-569: 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
20732-738: Was not put on display and remained in the museum's stores. In 1977, the Polish Aviation Museum exchanged F1010 for a Supermarine Spitfire from the RAF Museum (difficulties caused by the Cold War meant nearly nine years were spent negotiating the swap). The RAF Museum completed restoration of the aircraft and put it on display in 1983. Data from The British Bomber since 1914 General characteristics Performance Armament Related development Related lists First World War World War I or
20878-458: 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
21024-654: Was refused. Early on the morning of 4 August, the Germans invaded, and Albert I of Belgium called for assistance under the Treaty of London . Britain sent Germany an ultimatum demanding they withdraw from Belgium; when this expired at midnight, without a response, the two empires were at war. Germany promised to support Austria-Hungary's invasion of Serbia, but interpretations of what this meant differed. Previously tested deployment plans had been replaced early in 1914, but those had never been tested in exercises. Austro-Hungarian leaders believed Germany would cover its northern flank against Russia. Beginning on 12 August,
21170-667: Was returning to Germany when it sank two British armoured cruisers at the Battle of Coronel in November 1914, before being virtually destroyed at the Battle of the Falkland Islands in December. The SMS Dresden escaped with a few auxiliaries, but after the Battle of Más a Tierra , these too were either destroyed or interned. Soon after the outbreak of hostilities, Britain began a naval blockade of Germany . This proved effective in cutting off vital supplies, though it violated accepted international law. Britain also mined international waters which closed off entire sections of
21316-781: Was the foundation of German foreign policy but in 1890, he was forced to retire by Wilhelm II . The latter was persuaded not to renew the Reinsurance Treaty by his new Chancellor , Leo von Caprivi . This gave France an opening to agree the Franco-Russian Alliance in 1894, which was then followed by the 1904 Entente Cordiale with Britain. The Triple Entente was completed by the 1907 Anglo-Russian Convention . While not formal alliances, by settling long-standing colonial disputes in Asia and Africa, British support for France or Russia in any future conflict became
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