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41-491: The Stemme S10 also has several unusual features such as a tailwheel undercarriage and a side-by-side cockpit. It does not have a tow hook connection so it must self-launch. The two main wheels retract and lower electrically, though they can also be lowered manually if needed. There is an option to fold wings to reduce hangar span to 11.4 m (37 ft 5 in). The engine restart time is 5 seconds. A solar panel can provide additional electrical power during long flights. It has

82-441: A crankshaft or by a swashplate or other suitable mechanism. A flywheel is often used to ensure smooth rotation or to store energy to carry the engine through an un-powered part of the cycle. The more cylinders a reciprocating engine has, generally, the more vibration-free (smoothly) it can operate. The power of a reciprocating engine is proportional to the volume of the combined pistons' displacement. A seal must be made between

123-459: A flywheel , the power from other pistons connected to the same shaft or (in a double acting cylinder ) by the same process acting on the other side of the piston. This is where the piston forms the smallest volume in the cylinder. In most types the expanded or " exhausted " gases are removed from the cylinder by this stroke . The exception is the Stirling engine , which repeatedly heats and cools

164-577: A piston engine , is typically a heat engine that uses one or more reciprocating pistons to convert high temperature and high pressure into a rotating motion . This article describes the common features of all types. The main types are: the internal combustion engine , used extensively in motor vehicles ; the steam engine , the mainstay of the Industrial Revolution ; and the Stirling engine for niche applications. Internal combustion engines are further classified in two ways: either

205-440: A spark-ignition (SI) engine , where the spark plug initiates the combustion; or a compression-ignition (CI) engine , where the air within the cylinder is compressed, thus heating it , so that the heated air ignites fuel that is injected then or earlier . There may be one or more pistons. Each piston is inside a cylinder , into which a gas is introduced, either already under pressure (e.g. steam engine ), or heated inside

246-413: A spoiler (sometimes called a lift spoiler or lift dumper ) is a device which intentionally reduces the lift component of an airfoil in a controlled way. Most often, spoilers are plates on the top surface of a wing that can be extended upward into the airflow to spoil the streamline flow. By so doing, the spoiler creates a controlled stall over the portion of the wing behind it, greatly reducing

287-597: A capacity of 1,820 L (64 cu ft), making a total capacity of 25,480 L (900 cu ft) for the largest versions. For piston engines, an engine's capacity is the engine displacement , in other words the volume swept by all the pistons of an engine in a single movement. It is generally measured in litres (l) or cubic inches (c.i.d., cu in, or in ) for larger engines, and cubic centimetres (abbreviated cc) for smaller engines. All else being equal, engines with greater capacities are more powerful and consumption of fuel increases accordingly (although this

328-469: A cylinder to drive a reciprocating engine in a local-pollution-free urban vehicle. Torpedoes may use a working gas produced by high test peroxide or Otto fuel II , which pressurize without combustion. The 230 kg (510 lb) Mark 46 torpedo , for example, can travel 11 km (6.8 mi) underwater at 74 km/h (46 mph) fuelled by Otto fuel without oxidant . Quantum heat engines are devices that generate power from heat that flows from

369-418: A dozen cylinders or more. Cylinder capacities may range from 10 cm or less in model engines up to thousands of liters in ships' engines. The compression ratio affects the performance in most types of reciprocating engine. It is the ratio between the volume of the cylinder, when the piston is at the bottom of its stroke, and the volume when the piston is at the top of its stroke. The bore/stroke ratio

410-406: A hot to a cold reservoir. The mechanism of operation of the engine can be described by the laws of quantum mechanics . Quantum refrigerators are devices that consume power with the purpose to pump heat from a cold to a hot reservoir. In a reciprocating quantum heat engine, the working medium is a quantum system such as spin systems or a harmonic oscillator. The Carnot cycle and Otto cycle are

451-572: A seal, and more heavily when higher combustion pressure moves around to their inner surfaces. It is common to classify such engines by the number and alignment of cylinders and total volume of displacement of gas by the pistons moving in the cylinders usually measured in cubic centimetres (cm or cc) or litres (l) or (L) (US: liter). For example, for internal combustion engines, single and two-cylinder designs are common in smaller vehicles such as motorcycles , while automobiles typically have between four and eight, and locomotives and ships may have

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492-484: A sequence of strokes that admit and remove gases to and from the cylinder. These operations are repeated cyclically and an engine is said to be 2-stroke , 4-stroke or 6-stroke depending on the number of strokes it takes to complete a cycle. The most common type is 4-stroke, which has following cycles. The reciprocating engine developed in Europe during the 18th century, first as the atmospheric engine then later as

533-562: A steerable tailwheel, Schempp-Hirth spoilers and optional winglets . The current variant, the S10-VT, has a variable-pitch propeller which allows more power during take off, and a new turbocharged Bombardier Rotax 914F engine in place of the earlier Limbach L2400. Most parts are made in Poland, but future production will be handled by Remos Aircraft . First seen at the 1996 Berlin Air Show,

574-433: A system called Direct Lift Control that used the spoilers on landing approach to control descent. Airbus aircraft with fly-by-wire control utilise wide-span spoilers for descent control, spoilerons, gust alleviation, and lift dumpers. Especially on landing approach, the full width of spoilers can be seen controlling the aircraft's descent rate and bank. Lift dumpers are a special type of spoiler extending along much of

615-530: Is limited by higher speeds. For such spoilers the term spoileron has been coined. In the case of a spoileron, in order for it to be used as a control surface, it is raised on one wing only, thus decreasing lift and increasing drag, causing roll and yaw. Eliminating dedicated ailerons also avoids the problem of control reversal and allows flaps to occupy a greater portion of the wing trailing edge. Almost all modern jet airliners are fitted with inboard lift spoilers which are used together during descent to increase

656-586: Is not to be confused with fuel efficiency , since high efficiency often requires a lean fuel-air ratio, and thus lower power density. A modern high-performance car engine makes in excess of 75 kW/L (1.65 hp/in ). Reciprocating engines that are powered by compressed air, steam or other hot gases are still used in some applications such as to drive many modern torpedoes or as pollution-free motive power. Most steam-driven applications use steam turbines , which are more efficient than piston engines. The French-designed FlowAIR vehicles use compressed air stored in

697-412: Is not true of every reciprocating engine), although power and fuel consumption are affected by many factors outside of engine displacement. Reciprocating engines can be characterized by their specific power , which is typically given in kilowatts per litre of engine displacement (in the U.S. also horsepower per cubic inch). The result offers an approximation of the peak power output of an engine. This

738-613: Is selected and, on touchdown, a sensor called a weight-on-wheels switch signals the lift dumpers to be raised. The flight control spoilers are also raised as additional lift dumpers. Virtually all modern jet aircraft are fitted with lift dumpers. The British Aerospace 146 is fitted with particularly wide-span spoilers to generate additional drag and make reverse thrust unnecessary. A number of accidents have been caused either by inadvertently deploying lift dumpers on landing approach, or forgetting to set them to "automatic". Piston engine A reciprocating engine , also often known as

779-394: Is the fictitious pressure which would produce the same amount of net work that was produced during the power stroke cycle. This is shown by: where A p {\displaystyle A_{p}} is the total piston area of the engine, S {\displaystyle S} is the stroke length of the pistons, and V d {\displaystyle V_{d}}

820-459: Is the ratio of the diameter of the piston, or " bore ", to the length of travel within the cylinder, or "stroke". If this is around 1 the engine is said to be "square". If it is greater than 1, i.e. the bore is larger than the stroke, it is "oversquare". If it is less than 1, i.e. the stroke is larger than the bore, it is "undersquare". Cylinders may be aligned in line , in a V configuration , horizontally opposite each other, or radially around

861-425: Is the total displacement volume of the engine. Therefore: Whichever engine with the larger value of MEP produces more net work per cycle and performs more efficiently. In steam engines and internal combustion engines, valves are required to allow the entry and exit of gases at the correct times in the piston's cycle. These are worked by cams, eccentrics or cranks driven by the shaft of the engine. Early designs used

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902-423: Is then fed through one or more, increasingly larger bore cylinders successively, to extract power from the steam at increasingly lower pressures. These engines are called compound engines . Aside from looking at the power that the engine can produce, the mean effective pressure (MEP), can also be used in comparing the power output and performance of reciprocating engines of the same size. The mean effective pressure

943-452: The D slide valve but this has been largely superseded by piston valve or poppet valve designs. In steam engines the point in the piston cycle at which the steam inlet valve closes is called the cutoff and this can often be controlled to adjust the torque supplied by the engine and improve efficiency. In some steam engines, the action of the valves can be replaced by an oscillating cylinder . Internal combustion engines operate through

984-737: The S15 variant has a span reduced to 20.0 m (65 ft 7 in) and has two underwing hardpoints for scientific or surveillance sensor pods. There is also an unpiloted version, the S-UAV , again intended for surveillance. Atmospheric measurements were made with S10 VT during the Mountain Wave Project (MWP) Expedition Argentina'99 1,550 km (963 mi) record flight to Tierra del Fuego and during Expedition Mendoza 2006, when scientific measurements of atmospheric turbulence were made up to 12,500 m (41,010 ft) around and over

1025-420: The steam engine . These were followed by the Stirling engine and internal combustion engine in the 19th century. Today the most common form of reciprocating engine is the internal combustion engine running on the combustion of petrol , diesel , liquefied petroleum gas (LPG) or compressed natural gas (CNG) and used to power motor vehicles and engine power plants . One notable reciprocating engine from

1066-489: The World War II era was the 28-cylinder, 3,500  hp (2,600 kW) Pratt & Whitney R-4360 Wasp Major radial engine. It powered the last generation of large piston-engined planes before jet engines and turboprops took over from 1944 onward. It had a total engine capacity of 71.5 L (4,360 cu in), and a high power-to-weight ratio . The largest reciprocating engine in production at present, but not

1107-477: The crankshaft. Opposed-piston engines put two pistons working at opposite ends of the same cylinder and this has been extended into triangular arrangements such as the Napier Deltic . Some designs have set the cylinders in motion around the shaft, such as the rotary engine . In some steam engines, the cylinders may be of varying size with the smallest bore cylinder working the highest pressure steam. This

1148-430: The cylinder either by ignition of a fuel air mixture ( internal combustion engine ) or by contact with a hot heat exchanger in the cylinder ( Stirling engine ). The hot gases expand, pushing the piston to the bottom of the cylinder. This position is also known as the bottom dead center (BDC), or where the piston forms the largest volume in the cylinder. The piston is returned to the cylinder top (top dead center) (TDC) by

1189-771: The highest mountain of the Americas, Aconcagua . An S10 was flown by Klaus Ohlmann as a pure glider for a record distance of 2,463 km (1,530 mi) , in a 14-hour flight. Two examples were used by the United States Air Force Academy between 1995 and 2002 under the designation TG-11A . In December 2017, the Colombian Air Force received two Stemme S10 VTs for training purposes. Data from Jane's All The World's Aircraft 2003–2004. General characteristics Performance Spoiler (aeronautics) In aeronautics ,

1230-604: The largest ever built, is the Wärtsilä-Sulzer RTA96-C turbocharged two-stroke diesel engine of 2006 built by Wärtsilä . It is used to power the largest modern container ships such as the Emma Mærsk . It is five stories high (13.5 m or 44 ft), 27 m (89 ft) long, and weighs over 2,300 metric tons (2,535 short tons ; 2,264 long tons ) in its largest 14 cylinders version producing more than 84.42 MW (113,209 bhp). Each cylinder has

1271-533: The lift of that wing section. Spoilers differ from airbrakes in that airbrakes are designed to increase drag without disrupting the lift distribution across the wing span, while spoilers disrupt the lift distribution as well as increasing drag. Spoilers fall into two categories: those that are deployed at controlled angles during flight to increase descent rate or control roll, and those that are fully deployed immediately on landing to greatly reduce lift ("lift dumpers") and increase drag. In modern fly-by-wire aircraft,

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1312-410: The ones most studied. The quantum versions obey the laws of thermodynamics . In addition, these models can justify the assumptions of endoreversible thermodynamics . A theoretical study has shown that it is possible and practical to build a reciprocating engine that is composed of a single oscillating atom. This is an area for future research and could have applications in nanotechnology . There are

1353-463: The rate of descent and control speed. Some aircraft use lift spoilers on landing approach to control descent without changing the aircraft's attitude. One jet airliner not fitted with lift spoilers was the Douglas DC-8 which used reverse thrust in flight on the two inboard engines to control descent speed (however the aircraft was fitted with lift dumpers). The Lockheed Tristar was fitted with

1394-505: The same sealed quantity of gas. The stroke is simply the distance between the TDC and the BDC, or the greatest distance that the piston can travel in one direction. In some designs the piston may be powered in both directions in the cylinder, in which case it is said to be double-acting . In most types, the linear movement of the piston is converted to a rotating movement via a connecting rod and

1435-469: The same set of control surfaces serve both functions. Spoilers were used by most gliders (sailplanes) until the 1960s to control their rate of descent and thus achieve a controlled landing. Since then, spoilers on gliders have almost entirely been replaced by airbrakes, usually of the Schempp-Hirth type. Spoilers and airbrakes enable the glide angle to be altered during the approach while leaving

1476-540: The situation by allowing the aircraft to descend at a desired rate while letting the engine run at a power setting that keeps it from cooling too quickly (especially true for turbocharged piston engines, which generate higher temperatures than normally aspirated engines). Spoiler controls can be used for roll control (outboard or mid-span spoilers) or descent control (inboard spoilers). Some aircraft use spoilers in combination with or in lieu of ailerons for roll control, primarily to reduce adverse yaw when rudder input

1517-407: The sliding piston and the walls of the cylinder so that the high pressure gas above the piston does not leak past it and reduce the efficiency of the engine. This seal is usually provided by one or more piston rings . These are rings made of a hard metal, and are sprung into a circular groove in the piston head. The rings fit closely in the groove and press lightly against the cylinder wall to form

1558-458: The speed unchanged. Airliners are almost always fitted with spoilers. Spoilers are used to increase descent rate without increasing speed. Their use is often limited, however, as the turbulent airflow that develops behind them causes noise and vibration, which may cause discomfort to passengers. Spoilers may also be differentially operated for roll control instead of ailerons ; Martin Aircraft

1599-407: The wheels to be mechanically braked with less tendency to skid. In air-cooled piston engine aircraft, spoilers may be needed to avoid shock cooling the engines. In a descent without spoilers, air speed is increased and the engine will be at low power, producing less heat than normal. The engine may cool too rapidly, resulting in stuck valves, cracked cylinders or other problems. Spoilers alleviate

1640-531: The wing's length and designed to dump as much lift as possible on landing. Lift dumpers have only two positions, deployed and retracted. Lift dumpers have three main functions: putting most of the weight of the aircraft on the wheels for maximum braking effect, increasing form drag , and preventing aircraft "bounce" on landing. Lift dumpers are almost always deployed automatically on touch down. The flight deck control has three positions: off, automatic ("armed"), and manual (rarely used). On landing approach "automatic"

1681-414: Was the first company to develop such spoilers in 1948. On landing , however, the spoilers are nearly always fully deployed to help slow the aircraft. The increase in form drag created by the spoilers directly assists the braking effect. However, the most gain comes as the spoilers cause a dramatic loss of lift and hence the weight of the aircraft is transferred from the wings to the undercarriage, allowing

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