Misplaced Pages

#901098

106-657: During World War I , the British Coastal class blimps , one of several types of airship operated by the Royal Navy , carried a 1.75 horsepower (1.30 kW) ABC auxiliary engine. These powered a generator for the craft's radio transmitter and, in an emergency, could power an auxiliary air blower. One of the first military fixed-wing aircraft to use an APU was the British, World War 1, Supermarine Nighthawk , an anti-Zeppelin night fighter . During World War II ,

212-590: 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

318-464: A gas turbine APU, allowing it to operate at smaller airports, independent from ground facilities. The APU can be identified on many modern airliners by an exhaust pipe at the aircraft's tail. A typical gas-turbine APU for commercial transport aircraft comprises three main sections: The power section is the gas-generator portion of the engine and produces all the shaft power for the APU. In this section of

424-592: 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,

530-540: 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

636-454: A bleedless aircraft such as the Boeing 787 , each engine has two variable-frequency electrical generators to compensate for not providing compressed air to external systems. Eliminating bleed air and replacing it with extra electric generation is believed to provide a net improvement in engine efficiency, lower weight, and ease of maintenance. According to Boeing internal documents, eliminating

742-408: 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

848-613: 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

954-627: A fuel cell APU that eliminates nearly all emissions and uses diesel fuel more efficiently. In 2008, a DOE sponsored partnership between Delphi Electronics and Peterbilt demonstrated that a fuel cell could provide power to the electronics and air conditioning of a Peterbilt Model 386 under simulated "idling" conditions for ten hours. Delphi has said the 5 kW system for Class 8 trucks will be released in 2012, at an $ 8000–9000 price tag that would be competitive with other "midrange" two-cylinder diesel APUs, should they be able to meet those deadlines and cost estimates. World War I World War I or

1060-471: 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,

1166-516: A number of large American military aircraft were fitted with APUs. These were typically known as putt–putts , even in official training documents. The putt-putt on the B-29 Superfortress bomber was fitted in the unpressurised section at the rear of the aircraft. Various models of four-stroke, Flat-twin or V-twin engines were used. The 7 horsepower (5.2 kW) engine drove a P2 , DC generator, rated 28.5 Volts and 200 Amps (several of

SECTION 10

#1732783713902

1272-460: A pilot who had suffered toxic encephalopathy (brain damage) from a fume event condemned the airline industry's obstructionism around fume events. In July 2015, pilots on a Spirit Airlines flight were partially incapacitated by fumes in bleed air. Bleed air systems have been in use for several decades in passenger jets. Recent improvements in solid-state electronics have enabled pneumatic power systems to be replaced by electric power systems. In

1378-542: A pioneering example of an auxiliary power unit for starting a jet engine. A hole in the extreme nose of the diverter contained a manual pull-handle which started the piston engine, which in turn rotated the compressor. Two spark plug access ports existed in the Jumo 004's intake diverter to service the Riedel unit's cylinders in situ, for maintenance purposes. Two small "premix" tanks for the Riedel's petrol/ oil fuel were fitted in

1484-548: 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

1590-834: 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

1696-516: 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

1802-628: A study made for the EU in 2014 confirmed that contamination of cabin air could be a problem, that study also stated: While no scientific evidence to date has found that airliner cabin air has been contaminated to toxic levels (exceeding known safe levels, in ppm, of any dangerous chemical), a court in Australia in March 2010 found in favor of a former airline flight attendant who claimed she suffered chronic respiratory problems after being exposed to oil fumes on

1908-460: A trip in March 1992. Such testing is infrequent due to Boeing's refusal to install air quality sensors in its planes, fearing lawsuits from crew or passengers over fume events, and airlines refused to allow flight attendants to carry air samplers after Congress mandated chemical measurements. The FAA has revoked the medical certificates of several pilots who developed neurological issues after fume events. A judge who awarded workers' compensation to

2014-478: 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

2120-402: 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

2226-455: 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

SECTION 20

#1732783713902

2332-536: Is common to use bleed air to inflate a rubber boot on the leading edge, breaking the ice loose after it has already formed. Bleed air from the high-pressure compressor of the engine is used to supply reaction control valves as used for part of the flight control system in the Harrier family of military aircraft. On about 1 in 5,000 flights, bleed air used for air conditioning and pressurization can be contaminated by chemicals such as oil or hydraulic fluid. This

2438-426: Is known as a fume event. While those chemicals can be irritating, such events have not been established to cause long-term harm. Certain neurological and respiratory ill health effects have been linked anecdotally to exposure to bleed air that has been alleged to have been contaminated with toxic levels on commercial and military aircraft. This alleged long-term illness is referred to as aerotoxic syndrome , but it

2544-508: 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

2650-908: Is not a medically recognized syndrome. One potential contaminant is tricresyl phosphate . Many lobbying groups have been set up to advocate for research into this hazard, including the Aviation Organophosphate Information Site (AOPIS) (2001), the Global Cabin Air Quality Executive (2006) and the UK-based Aerotoxic Association (2007). Cabin Environment Research is one of many functions of the ACER Group, but their researchers have not yet established any causal relationship . Although

2756-421: Is the same air being recycled. Bleed air is also used to heat the engine intakes . This prevents ice from forming, accumulating, breaking loose, and being ingested by the engine, which could damage it. On aircraft powered by jet engines, a similar system is used for wing anti-icing by the 'hot-wing' method. In icing conditions, water droplets condensing on a wing's leading edge can freeze. If that happens,

2862-442: Is used during descent and other low power setting operations. Bleed air from that system can be utilized for internal cooling of the engine, cross-starting another engine, engine and airframe anti-icing , cabin pressurization , pneumatic actuators , air-driven motors, pressurizing the hydraulic reservoir, and waste and water storage tanks. Some engine maintenance manuals refer to such systems as "customer bleed air". Bleed air

2968-438: Is used to keep critical parts of the plane (such as the wing leading edges ) ice-free. Bleed air is used on many aircraft systems because it is easily available, reliable, and a potent source of power. For example, bleed air from an airplane engine is used to start the remaining engines. Lavatory water storage tanks are pressurized by bleed air that is fed through a pressure regulator . When used for cabin pressurization ,

3074-427: Is valuable in an aircraft for two properties: high temperature and high pressure (typical values are 200–250 °C (400–500 °F) and 275 kPa (40 psi), for regulated bleed air exiting the engine pylon for use throughout the aircraft). In civil aircraft, bleed air's primary use is to provide pressure for the aircraft cabin by supplying air to the environmental control system . Additionally, bleed air

3180-574: 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

3286-641: 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

Auxiliary power unit - Misplaced Pages Continue

3392-524: The APIC joint venture with Sundstrand in 1996. This could threaten the dominance of Honeywell and United Technologies . Honeywell has a 65% share of the mainliner APU market and is the sole supplier for the Airbus A350 , the Boeing 777 and all single-aisles : the Boeing 737 MAX , Airbus A220 (formerly Bombardier CSeries), Comac C919 , Irkut MC-21 and Airbus A320neo since Airbus eliminated

3498-695: 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

3604-622: The Douglas C-47 Skytrain transport aircraft carried a putt-putt under the cockpit floor. The first German jet engines built during the Second World War used a mechanical APU starting system designed by the German engineer Norbert Riedel . It consisted of a 10 horsepower (7.5 kW) two-stroke flat engine , which for the Junkers Jumo 004 design was hidden in the intake diverter, essentially functioning as

3710-847: 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

3816-721: 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,

3922-776: 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

4028-487: 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

4134-821: 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

4240-588: 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

4346-563: 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

Auxiliary power unit - Misplaced Pages Continue

4452-441: 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

4558-564: The APU delivers only electricity to the aircraft. The absence of a pneumatic system simplifies the design, but high demand for electricity requires heavier generators. Onboard solid oxide fuel cell ( SOFC ) APUs are being researched. The market of Auxiliary power units is dominated by Honeywell , followed by Pratt & Whitney , Motorsich and other manufacturers such as PBS Velká Bíteš , Safran Power Units , Aerosila and Klimov . Local manufacturers include Bet Shemesh Engines and Hanwha Aerospace . The 2018 market share varied according to

4664-550: The APUs provided hydraulic power for gimballing of the Shuttle's three engines and control of their large valves, and for movement of the control surfaces . During landing, they moved the control surfaces, lowered the wheels, and powered the brakes and nose-wheel steering. Landing could be accomplished with only one APU working. In the early years of the Shuttle there were problems with APU reliability, with malfunctions on three of

4770-569: 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,

4876-646: 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

4982-553: 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 ,

5088-404: 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

5194-649: 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

5300-623: 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

5406-640: 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

SECTION 50

#1732783713902

5512-752: 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

5618-486: 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

5724-565: 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

5830-703: 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

5936-545: 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,

6042-449: 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

6148-610: The P&WC APS3200 option. P&WC claims the remaining 35% with the Airbus A380 , Boeing 787 and Boeing 747-8 . It should take at least a decade for the Boeing/Safran JV to reach $ 100 million in service revenue. The 2017 market for production was worth $ 800 million (88% civil and 12% military), while the MRO market was worth $ 2.4 billion, spread equally between civil and military. The Space Shuttle APUs provided hydraulic pressure. The Space Shuttle had three redundant APUs, powered by hydrazine fuel. They were only powered up for ascent, re-entry , and landing. During ascent,

6254-549: 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

6360-429: 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

6466-455: 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

SECTION 60

#1732783713902

6572-430: 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

6678-446: 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

6784-434: The aircraft, though some APUs extract bleed air from the power section compressor. There are two actuated devices to help control the flow of air: the inlet guide vanes that regulate airflow to the load compressor and the surge control valve that maintains stable or surge-free operation of the turbo machine. The gearbox transfers power from the main shaft of the engine to an oil-cooled generator for electrical power. Within

6890-411: The annular intake. The engine was considered an extreme short stroke (bore / stroke: 70 mm / 35 mm = 2:1) design so it could fit within the intake diverter of jet engines like the Jumo 004. For reduction it had an integrated planetary gear . It was produced by Victoria in Nuremberg and served as a mechanical APU-style starter for all three German jet engine designs to have made it to at least

6996-417: The application platforms: On June 4, 2018, Boeing and Safran announced their 50–50 partnership to design, build and service APUs after regulatory and antitrust clearance in the second half of 2018. Boeing produced several hundred T50 / T60 small turboshafts and their derivatives in the early 1960s. Safran produces helicopters and business jets APUs but stopped the large APUs since Labinal exited

7102-407: 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

7208-477: 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

7314-451: The bleed air from the engine must first be cooled as it exits the compressor stage at temperatures as high as 250 °C (500 °F) by passing it through an air-to-air heat exchanger cooled by the cold outside air. It is then fed to an air cycle machine unit that regulates the temperature and flow of air into the cabin, keeping the environment comfortable. This process is contrary to the common misconception that cabin air in airplanes

7420-483: 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

7526-427: 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,

7632-649: 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

7738-466: 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,

7844-520: 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,

7950-522: 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

8056-449: 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

8162-965: 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

8268-414: The engine, air and fuel are mixed, compressed and ignited to create hot and expanding gases. This gas is highly energetic and is used to spin the turbine, which in turn powers other sections of the engine, such as auxiliary gearboxes, pumps, electrical generators, and in the case of a turbo fan engine, the main fan. The load compressor is generally a shaft-mounted compressor that provides pneumatic power for

8374-695: 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

8480-671: The first nine Shuttle missions. APUs are fitted to some tanks to provide electrical power without the high fuel consumption and large infrared signature of the main engine. As early as World War II, the American M4 Sherman had a small, piston-engine powered APU for charging the tank's batteries, a feature the Soviet-produced T-34 tank did not have. A refrigerated or frozen food semi trailer or train car may be equipped with an independent APU and fuel tank to maintain low temperatures while in transit, without

8586-463: 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

8692-595: 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

8798-453: The gearbox, power is also transferred to engine accessories such as the fuel control unit, the lubrication module, and cooling fan. There is also a starter motor connected through the gear train to perform the starting function of the APU. Some APU designs use a combination starter/generator for APU starting and electrical power generation to reduce complexity. On the Boeing 787 , an aircraft which has greater reliance on its electrical systems,

8904-542: 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

9010-549: 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

9116-412: The ice build-up adds weight and changes the shape of the wing, causing a degradation in performance and possibly a critical loss of control or lift . To prevent this, hot bleed air is pumped through the inside of the wing's leading edge, heating it to a temperature above freezing, which prevents the formation of ice. The air then exits through small holes in the wing edge. On propeller-driven aircraft, it

9222-435: 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

9328-470: 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

9434-442: The line, but these forces were too weak to re-establish a front. Bleed air Bleed air in aerospace engineering is compressed air taken from the compressor stage of a gas turbine , upstream of its fuel-burning sections. Automatic air supply and cabin pressure controller (ASCPC) valves bleed air from low or high stage engine compressor sections; low stage air is used during high power setting operation, and high stage air

9540-427: The main engines are not operating. Aerodynamics are improved due to the lack of bleed air vent holes on the wings. By driving cabin air supply compressors at the minimum required speed, no energy wasting modulating valves are required. High-temperature, high-pressure air cycle machine (ACM) packs can be replaced with low temperature, low-pressure packs to increase efficiency. At cruise altitude, where most aircraft spend

9646-485: The majority of their time and burn the majority of their fuel, the ACM packs can be bypassed entirely, saving even more energy. Since no bleed air is taken from the engines for the cabin, the potential of engine oil contamination of the cabin air supply is eliminated. Lastly, advocates of the design say it improves safety as heated air is confined to the engine pod, as opposed to being pumped through pipes and heat exchangers in

9752-531: The need for an external transport-supplied power source. On some older diesel engined-equipment, a small gasoline engine (often called a "pony engine") was used instead of an electric motor to start the main engine. The exhaust path of the pony engine was typically arranged so as to warm the intake manifold of the diesel, to ease starting in colder weather. These were primarily used on large pieces of construction equipment. In recent years, truck and fuel cell manufacturers have teamed up to create, test and demonstrate

9858-465: 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

9964-801: 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

10070-571: The prototype stage before May 1945 – the Junkers Jumo 004 , the BMW 003 (which uniquely appears to use an electric starter for the Riedel APU), and the prototypes (19 built) of the more advanced Heinkel HeS 011 engine, which mounted it just above the intake passage in the Heinkel-crafted sheetmetal of the engine nacelle nose. The Boeing 727 in 1963 was the first jetliner to feature

10176-602: The same P2 generators, driven by the main engines , were the B-29's DC power source in flight). The putt-putt provided power for starting the main engines and was used after take-off to a height of 10,000 feet (3,000 m). The putt-putt was restarted when the B-29 was descending to land. Some models of the B-24 Liberator had a putt–putt fitted at the front of the aircraft, inside the nose-wheel compartment. Some models of

10282-469: 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

10388-691: 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

10494-452: The use of bleed air as a source of cabin air also translates into the “elimination of engine contaminants potentially entering cabin air supply.” A bleedless aircraft achieves fuel efficiency by eliminating the process of compressing and decompressing air, and by reducing the aircraft's mass due to the removal of ducts, valves, heat exchangers, and other heavy equipment. The APU (auxiliary power unit) does not need to supply bleed air when

10600-645: 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

10706-601: 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

10812-477: 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

10918-403: 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

11024-654: 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,

11130-667: 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

11236-781: 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

#901098