An aircraft engine , often referred to as an aero engine , is the power component of an aircraft propulsion system . Aircraft using power components are referred to as powered flight . Most aircraft engines are either piston engines or gas turbines , although a few have been rocket powered and in recent years many small UAVs have used electric motors .
112-515: Continental Aerospace Technologies is an aircraft engine manufacturer located at the Brookley Aeroplex in Mobile, Alabama , United States . It was originally spun off from automobile engine manufacturer Continental Motors Company in 1929 and owned by Teledyne Technologies from 1969 until December 2010. The company is now part of Aviation Industry Corporation of China (AVIC), which
224-526: A Beechcraft Bonanza and ground testing in Continental O-200 , 240 , O-470 , and O-520 engines. In May 2010, TCM indicated that despite industry skepticism, they are proceeding with 94UL and that certification was expected in mid-2013. In June 2010, Lycoming Engines indicated their opposition to 94UL. Company general manager Michael Kraft stated that aircraft owners do not realize how much performance would be lost with 94UL and characterized
336-443: A gas turbine engine offered. Thus was born the idea to mate a turbine engine to a traditional propeller. Because gas turbines optimally spin at high speed, a turboprop features a gearbox to lower the speed of the shaft so that the propeller tips don't reach supersonic speeds. Often the turbines that drive the propeller are separate from the rest of the rotating components so that they can rotate at their own best speed (referred to as
448-400: A "fuel return" line to send unused fuel back to the tank, which has the benefit of equalizing the fuel's temperature throughout the system, further reducing the chance of vapor lock developing. In addition to vapor locking potential, automotive gasoline does not have the same quality tracking as aviation gasoline. To help solve this problem, the specification for an aviation fuel known as 82UL
560-701: A 50% stake in Continental Motors. In 1969, Teledyne Incorporated acquired Continental Motors, which became Teledyne Continental Motors (TCM). That same year, the Continental Tiara series of high output engines were introduced, although they were dropped from the line after 1978. The company brought the TSIO-520-BE for the Piper PA-46 to market in 1984 and it set new efficiency standards for light aircraft piston engines. Powered by
672-510: A 91/96 avgas and have STCs available to run "premium" 91 anti-knock index (AKI) automotive gasoline. Examples include some Cherokees with the 160 hp (120 kW) Lycoming O-320 or 180 hp (130 kW) O-360 , or the Cessna 152 with the O-235 . The AKI rating of typical automotive fuel might not directly correspond to the 91/96 avgas used to certify engines, as motor vehicle pumps in
784-494: A FAA approved industry replacement by 2018. In July 2021, the first commercially-produced unleaded avgas, GAMI's G100UL , was approved by the Federal Aviation Administration through a Supplemental Type Certificate . Lycoming Engines provides a list of engines and fuels that are compatible with unleaded fuel. However, all of their engines require that an oil additive be used when unleaded fuel
896-562: A Lycoming O-360-A4M in 2013. The fuel is certified under Lycoming Service Instruction 1070 and ASTM D4814. Unleaded 94 Motor octane fuel ( UL94 ) is essentially 100LL without the lead. In March 2009, Teledyne Continental Motors (TCM) announced they had tested a 94UL fuel that might be the best replacement for 100LL. This 94UL meets the avgas specification including vapor pressure but has not been completely tested for detonation qualities in all Continental engines or under all conditions. Flight testing has been conducted in an IO-550-B powering
1008-618: A better efficiency. A hybrid system as emergency back-up and for added power in take-off is offered for sale by Axter Aerospace, Madrid, Spain. Small multicopter UAVs are almost always powered by electric motors. Reaction engines generate the thrust to propel an aircraft by ejecting the exhaust gases at high velocity from the engine, the resultant reaction of forces driving the aircraft forwards. The most common reaction propulsion engines flown are turbojets, turbofans and rockets. Other types such as pulsejets , ramjets , scramjets and pulse detonation engines have also flown. In jet engines
1120-555: A checklist of 12 fuel specification parameters and 4 distribution and storage parameters. The FAA has requested a maximum of US$ 60M to fund the administration of the changeover. In July 2014, nine companies and consortiums submitted proposals to the Piston Aviation Fuels Initiative (PAFI) to assess fuels without tetraethyl lead. Phase one testing is performed at the William J. Hughes Technical Center for
1232-419: A combustion section where fuel is added and ignited, one or more turbines that extract power from the expanding exhaust gases to drive the compressor, and an exhaust nozzle that accelerates the exhaust gases out the back of the engine to create thrust. When turbojets were introduced, the top speed of fighter aircraft equipped with them was at least 100 miles per hour faster than competing piston-driven aircraft. In
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#17327728941171344-564: A common crankshaft. The vast majority of V engines are water-cooled. The V design provides a higher power-to-weight ratio than an inline engine, while still providing a small frontal area. Perhaps the most famous example of this design is the legendary Rolls-Royce Merlin engine, a 27-litre (1649 in ) 60° V12 engine used in, among others, the Spitfires that played a major role in the Battle of Britain . A horizontally opposed engine, also called
1456-490: A cooling system into the air duct of a hydrogen jet engine permits greater fuel injection at high speed and obviates the need for the duct to be made of refractory or actively cooled materials. This greatly improves the thrust/weight ratio of the engine at high speed. It is thought that this design of engine could permit sufficient performance for antipodal flight at Mach 5, or even permit a single stage to orbit vehicle to be practical. The hybrid air-breathing SABRE rocket engine
1568-440: A cylinder on the other side. Opposed, air-cooled four- and six-cylinder piston engines are by far the most common engines used in small general aviation aircraft requiring up to 400 horsepower (300 kW) per engine. Aircraft that require more than 400 horsepower (300 kW) per engine tend to be powered by turbine engines . An H configuration engine is essentially a pair of horizontally opposed engines placed together, with
1680-408: A flat or boxer engine, has two banks of cylinders on opposite sides of a centrally located crankcase. The engine is either air-cooled or liquid-cooled, but air-cooled versions predominate. Opposed engines are mounted with the crankshaft horizontal in airplanes , but may be mounted with the crankshaft vertical in helicopters . Due to the cylinder layout, reciprocating forces tend to cancel, resulting in
1792-443: A four-day work week with one week vacations for Thanksgiving and Christmas, with the aim "to protect as much of our valuable employee base as possible". On 14 December 2010, Continental's parent Teledyne announced that Teledyne Continental Motors, Teledyne Mattituck Services, and its general aviation piston engine business would be sold to Technify Motor (USA) Ltd, a subsidiary of AVIC International , for US$ 186 million in cash. AVIC
1904-572: A fraction of the cost of traditional engines. Such conversions first took place in the early 1970s; and as of 10 December 2006 the National Transportation Safety Board has only seven reports of incidents involving aircraft with Mazda engines, and none of these is of a failure due to design or manufacturing flaws. The most common combustion cycle for aero engines is the four-stroke with spark ignition. Two-stroke spark ignition has also been used for small engines, while
2016-407: A free-turbine engine). A turboprop is very efficient when operated within the realm of cruise speeds it was designed for, which is typically 200 to 400 mph (320 to 640 km/h). Turboshaft engines are used primarily for helicopters and auxiliary power units . A turboshaft engine is similar to a turboprop in principle, but in a turboprop the propeller is supported by the engine and the engine
2128-456: A handful of types are still in production. The last airliner that used turbojets was the Concorde , whose Mach 2 airspeed permitted the engine to be highly efficient. A turbofan engine is much the same as a turbojet, but with an enlarged fan at the front that provides thrust in much the same way as a ducted propeller , resulting in improved fuel efficiency . Though the fan creates thrust like
2240-653: A liquid-cooled version of the IO-240, the Rutan Voyager was the first piston-powered aircraft to circumnavigate the world without refueling in 1986. NASA selected Continental to develop and produce GAP in 1997, a new 200 hp (150 kW) piston engine to operate on Jet-A fuel. This was in response to 100-octane aviation gasoline becoming less available as a result of decreased demand, due to smaller turboprop engines becoming more prevalent. In 2008, Teledyne Continental's new president, Rhett Ross announced that
2352-569: A peak pressure of 30 MPa (300 bar). Although engine weight increases by 30%, aircraft fuel consumption is reduced by 15%. Sponsored by the European Commission under Framework 7 project LEMCOTEC , Bauhaus Luftfahrt, MTU Aero Engines and GKN Aerospace presented the concept in 2015, raising the overall engine pressure ratio to over 100 for a 15.2% fuel burn reduction compared to 2025 engines. On multi-engine aircraft, engine positions are numbered from left to right from
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#17327728941172464-478: A piston-engine with two 10 piston banks without a high-pressure turbine, increasing efficiency with non-stationary isochoric - isobaric combustion for higher peak pressures and temperatures. The 11,200 lb (49.7 kN) engine could power a 50-seat regional jet . Its cruise TSFC would be 11.5 g/kN/s (0.406 lb/lbf/hr) for an overall engine efficiency of 48.2%, for a burner temperature of 1,700 K (1,430 °C), an overall pressure ratio of 38 and
2576-424: A propeller, the surrounding duct frees it from many of the restrictions that limit propeller performance. This operation is a more efficient way to provide thrust than simply using the jet nozzle alone, and turbofans are more efficient than propellers in the transsonic range of aircraft speeds and can operate in the supersonic realm. A turbofan typically has extra turbine stages to turn the fan. Turbofans were among
2688-425: A search for replacement fuels for general aviation aircraft a priority for pilots’ organizations. Turbine engines and aircraft diesel engines burn various grades of jet fuel . Jet fuel is a relatively less volatile petroleum derivative based on kerosene , but certified to strict aviation standards, with additional additives. Model aircraft typically use nitro engines (also known as "glow engines" due to
2800-404: A smooth running engine. Opposed-type engines have high power-to-weight ratios because they have a comparatively small, lightweight crankcase. In addition, the compact cylinder arrangement reduces the engine's frontal area and allows a streamlined installation that minimizes aerodynamic drag. These engines always have an even number of cylinders, since a cylinder on one side of the crankcase "opposes"
2912-471: A special oil additive is used. The annual US usage of avgas was 186 million US gallons (700,000 m ) in 2008, and was approximately 0.14% of the motor gasoline consumption. From 1983 through 2008, US usage of avgas declined consistently by approximately 7.5 million US gallons (28,000 m ) each year. As of 2024, the annual US usage of avgas was 180 million US gallons (680,000 m ), most of which contained lead, and 170,000 aircraft in
3024-442: A toxic lead containing additive used to aid in lubrication of the engine, increase octane rating , and prevent engine knocking (premature detonation). There are ongoing efforts to reduce or eliminate the use of lead in aviation gasoline. Kerosene -based jet fuel is formulated to suit the requirements of turbine engines which have no octane requirement and operate over a much wider flight envelope than piston engines. Kerosene
3136-755: Is a Government of the People's Republic of China state-owned aerospace company headquartered in Beijing . Although Continental is most well known for its engines for light aircraft , it was also contracted to produce the air-cooled V-12 AV-1790 -5B gasoline engine for the U.S. Army's M47 Patton tank and the diesel AVDS-1790-2A and its derivatives for the M48 , M60 Patton , and Merkava main battle tanks . The company also produced engines for various independent manufacturers of automobiles, tractors, and stationary equipment (pumps, generators, and machinery drives) from
3248-576: Is a Chinese state-owned aerospace company. In May 2011, the transaction was reported as complete and the company renamed Continental Motors, Inc. On 23 July 2013 the company bought diesel aircraft engine manufacturer Thielert from bankruptcy for an undisclosed sum. Thielert will become an operating division of Continental and will be renamed Technify Motors GmbH . In 2015, Continental purchased Danbury Aerospace, which included ECi (Engine Components International) and PMA (Precision Machined Airparts). ECi had been supplying aftermarket engine parts since 1943;
3360-533: Is a pre-cooled engine under development. At the April 2018 ILA Berlin Air Show , Munich -based research institute de:Bauhaus Luftfahrt presented a high-efficiency composite cycle engine for 2050, combining a geared turbofan with a piston engine core. The 2.87 m diameter, 16-blade fan gives a 33.7 ultra-high bypass ratio , driven by a geared low-pressure turbine but the high-pressure compressor drive comes from
3472-449: Is a twin-spool engine, allowing only two different speeds for the turbines. Pulsejets are mechanically simple devices that—in a repeating cycle—draw air through a no-return valve at the front of the engine into a combustion chamber and ignite it. The combustion forces the exhaust gases out the back of the engine. It produces power as a series of pulses rather than as a steady output, hence the name. The only application of this type of engine
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3584-438: Is above and behind. In the Cessna 337 Skymaster , a push-pull twin-engine airplane, engine No. 1 is the one at the front of the fuselage, while engine No. 2 is aft of the cabin. Aircraft reciprocating (piston) engines are typically designed to run on aviation gasoline . Avgas has a higher octane rating than automotive gasoline to allow higher compression ratios , power output, and efficiency at higher altitudes. Currently
3696-472: Is acceptable to use on those aircraft and engines that are approved to operate with ... grade UL91 avgas that meets specification D7547." In August 2016, the FAA revised SAIB HQ-16-05 to include similar wording regarding the acceptability of using UL94 in aircraft and engines that are approved to operate with avgas that has a minimum Motor octane rating of 80 or lower, including Grade 80/87. The publication of
3808-445: Is also used by most diesel piston engines developed for aviation use, such as those by SMA Engines , Austro Engine , and Thielert . The main petroleum component used in blending avgas is alkylate , which is a mixture of various isooctanes. Some refineries also use reformate . All grades of avgas that meet CAN 2–3 , 25-M82 have a density of 6.01 pounds per US gallon (720 g/L) at 15 °C (59 °F). (6 lb/U.S. gal
3920-453: Is bolted to the airframe : in a turboshaft, the engine does not provide any direct physical support to the helicopter's rotors. The rotor is connected to a transmission which is bolted to the airframe, and the turboshaft engine drives the transmission. The distinction is seen by some as slim, as in some cases aircraft companies make both turboprop and turboshaft engines based on the same design. A number of electrically powered aircraft, such as
4032-493: Is commonly used in America for weight and balance computation.) Density increases to 6.41 pounds per US gallon (768 g/L) at −40 °C (−40 °F), and decreases by about 0.1% per 1 °C (1.8 °F) increase in temperature. Avgas has an emission coefficient (or factor) of 18.355 pounds per US gallon (2.1994 kg/L) of CO 2 or about 3.07 units of weight CO 2 produced per unit weight of fuel used. Avgas
4144-492: Is less volatile, with a Reid vapor pressure range of 5.5 to 7 psi, than automotive gasoline, with a range of 8 to 14 psi. A minimum limit ensures adequate volatility for engine starting. The upper limits are related to atmospheric pressure at sea level, 14.7 psi, for motor vehicles and ambient pressure at 22,000 ft, 6.25 psi, for aircraft. The lower avgas volatility reduces the chance of vapor lock in fuel lines at altitudes up to 22,000 ft. The particular mixtures in use today are
4256-400: Is located above the cylinders, it is called an inverted inline engine: this allows the propeller to be mounted high up to increase ground clearance, enabling shorter landing gear. The disadvantages of an inline engine include a poor power-to-weight ratio , because the crankcase and crankshaft are long and thus heavy. An in-line engine may be either air-cooled or liquid-cooled, but liquid-cooling
4368-600: Is manufactured to meet ASTM D7547. Many common Lycoming engines are certified to run on this particular grade of Avgas, and Cessna has approved the use of this fuel in a large number of their piston fleet. This fuel is also usable in any aircraft in Europe or the United Kingdom where the engine is certified to use it, whether or not the airframe is certified to do so, too. The firm Airworthy AutoGas tested an ethanol-free 93 anti-knock index (AKI) premium auto gas on
4480-720: Is more common because it is difficult to get enough air-flow to cool the rear cylinders directly. Inline engines were common in early aircraft; one was used in the Wright Flyer , the aircraft that made the first controlled powered flight. However, the inherent disadvantages of the design soon became apparent, and the inline design was abandoned, becoming a rarity in modern aviation. For other configurations of aviation inline engine, such as X-engines , U-engines , H-engines , etc., see Inline engine (aeronautics) . Cylinders in this engine are arranged in two in-line banks, typically tilted 60–90 degrees apart from each other and driving
4592-542: Is not a fully viable replacement for avgas in many aircraft, because many high-performance and/or turbocharged airplane engines require 100 octane fuel and modifications are necessary in order to use lower-octane fuel. Many general aviation aircraft engines were designed to run on 80/87 octane, roughly the standard (as unleaded fuel only, with the "{R+M}/2" 87 octane rating) for North American automobiles today. Direct conversions to run on automotive fuel are fairly common, by supplemental type certificate (STC). However,
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4704-400: Is not limited to engines with a single row of cylinders. This is typically to differentiate them from radial engines . A straight engine typically has an even number of cylinders, but there are instances of three- and five-cylinder engines. The greatest advantage of an inline engine is that it allows the aircraft to be designed with a low frontal area to minimize drag. If the engine crankshaft
4816-430: Is of lesser concern, rocket engines can be useful because they produce very large amounts of thrust and weigh very little. A rocket turbine engine is a combination of two types of propulsion engines: a liquid-propellant rocket and a turbine jet engine. Its power-to-weight ratio is a little higher than a regular jet engine, and works at higher altitudes. For very high supersonic/low hypersonic flight speeds, inserting
4928-416: Is required in their engines, and not unleaded auto fuels: "Current aircraft engines feature valve gear components which are designed for compatibility with the leaded ASTM D910 fuels. In such fuels, the lead acts as a lubricant, coating the contact areas between the valve, guide, and seat. The use of unleaded auto fuels with engines designed for leaded fuels can result in excessive exhaust valve seat wear due to
5040-479: Is similar to the anti-knock index or "pump rating" given to automotive gasoline in the US. The second number indicates the octane rating of the fuel tested to the " aviation rich " standard, which tries to simulate a supercharged condition with a rich mixture, elevated temperatures, and a high manifold pressure. For example, 100/130 avgas has an octane rating of 100 at the lean settings usually used for cruising and 130 at
5152-428: Is susceptible to phase-separation which is very possible due to the altitude/temperature changes light airplanes undergo in ordinary flight. This ethanol-treated fuel can flood the fuel system with water which can cause in-flight engine failure. Additionally, the phase-separated fuel can leave remaining portions that do not meet octane requirements due to the loss of the ethanol in the water-absorption process. Further,
5264-486: Is used: "When using the unleaded fuels identified in Table 1, Lycoming oil additive P/N LW-16702, or an equivalent finished product such as Aeroshell 15W-50, must be used." Lycoming also notes that the octane rating of the fuel used must also meet the requirements stated in the fuel specification, otherwise engine damage may occur due to detonation. Prior to 2022, Teledyne Continental Motors (TCM) indicated that leaded avgas
5376-527: The QinetiQ Zephyr , have been designed since the 1960s. Some are used as military drones . In France in late 2007, a conventional light aircraft powered by an 18 kW electric motor using lithium polymer batteries was flown, covering more than 50 kilometers (31 mi), the first electric airplane to receive a certificate of airworthiness . On 18 May 2020, the Pipistrel E-811 was
5488-684: The Rutan Quickie . The single-rotor engine was put into a Chevvron motor glider and into the Schleicher ASH motor-gliders. After the demise of MidWest, all rights were sold to Diamond of Austria, who have since developed a MkII version of the engine. As a cost-effective alternative to certified aircraft engines some Wankel engines, removed from automobiles and converted to aviation use, have been fitted in homebuilt experimental aircraft . Mazda units with outputs ranging from 100 horsepower (75 kW) to 300 horsepower (220 kW) can be
5600-517: The UK ) is an aviation fuel used in aircraft with spark-ignited internal combustion engines . Avgas is distinguished from conventional gasoline (petrol) used in motor vehicles , which is termed mogas (motor gasoline) in an aviation context. Unlike motor gasoline, which has been formulated without lead since the 1970s to allow the use of catalytic converters for pollution reduction, the most commonly used grades of avgas still contain tetraethyl lead ,
5712-424: The gyroscopic effects of the heavy rotating engine produced handling problems in aircraft and the engines also consumed large amounts of oil since they used total loss lubrication, the oil being mixed with the fuel and ejected with the exhaust gases. Castor oil was used for lubrication, since it is not soluble in petrol, and the resultant fumes were nauseating to the pilots. Engine designers had always been aware of
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#17327728941175824-424: The oxygen necessary for fuel combustion comes from the air, while rockets carry an oxidizer (usually oxygen in some form) as part of the fuel load, permitting their use in space. A turbojet is a type of gas turbine engine that was originally developed for military fighters during World War II . A turbojet is the simplest of all aircraft gas turbines. It consists of a compressor to draw air in and compress it,
5936-710: The 1920s to the 1960s. In 1929, the company introduced its first aircraft engine, a seven-cylinder radial designated as the A-70, with a displacement of 543.91 cu in (8.91L) that produced 170 hp (127 kW). In August 1929, the Continental Motors Company formed the Continental Aircraft Engine Company as a subsidiary to develop and produce its aircraft engines. As the Great Depression unwound, 1930 saw
6048-454: The 1950s, the A-65 was developed into the more powerful 90 hp (67 kW) C-90 and eventually into the 100 hp (75 kW) O-200 . The O-200 powered a very important airplane design milestone: the Cessna 150 . By the 1960s turbocharging and fuel injection arrived in general aviation and the company's IO-520 series came to dominate the market. In 1965, Ryan Aeronautical acquired
6160-487: The Atlantic. The high octane ratings were traditionally achieved by the addition of tetraethyllead , a highly toxic substance that was phased out of automotive use in most countries in the late 20th century. Leaded avgas is currently available in several grades with differing maximum lead concentrations. (Unleaded avgas is also available.) Because tetraethyllead is a toxic additive, the minimum amount needed to bring
6272-556: The Cirrus Owners and Pilots Association collectively formed the Clean 100 Octane Coalition to represent them on this issue and push for unleaded 100 octane avgas. In November 2015, UL94 was added as a secondary grade of unleaded aviation gasoline to ASTM D7547, which is the specification that governs UL91 unleaded avgas. UL91 is currently being sold in Europe. UL94 meets all of the same specification property limits as 100LL with
6384-764: The Clerget 14F Diesel radial engine (1939) has the same power to weight ratio as a gasoline radial. Improvements in Diesel technology in automobiles (leading to much better power-weight ratios), the Diesel's much better fuel efficiency and the high relative taxation of AVGAS compared to Jet A1 in Europe have all seen a revival of interest in the use of diesels for aircraft. Thielert Aircraft Engines converted Mercedes Diesel automotive engines, certified them for aircraft use, and became an OEM provider to Diamond Aviation for their light twin. Financial problems have plagued Thielert, so Diamond's affiliate — Austro Engine — developed
6496-719: The SAIB, especially the August 2016 revision, eliminated the need for many of the UL94 STCs being sold by Swift Fuels, as the majority of the aircraft on the STC's Approved Model List are type-certified to use 80-octane or lower avgas. On April 6, 2017, Lycoming Engines published Service Instruction 1070V, which adds UL94 as an approved grade of fuel for dozens of engine models, 60% of which are carbureted engines. Engines with displacements of 235, 320, 360, and 540 cubic inches make up almost 90% of
6608-449: The US use the so-called "(R + M)/2" averaged motor vehicle octane rating system as posted on gas station pumps. Sensitivity is roughly 8–10 points, meaning that a 91 AKI fuel might have a MON of as low as 86. The extensive testing process required to obtain an STC for the engine/airframe combination helps ensure that, for those eligible aircraft, 91 AKI fuel provides sufficient detonation margin under normal conditions. Automotive gasoline
6720-442: The US used leaded avgas. In Europe, avgas remains the most common piston-engine fuel. High prices have encouraged efforts to convert to diesel fuel , which is more readily available, less expensive, and has advantages for aviation use. Grades of avgas are identified by two numbers associated with its Motor Octane Number (MON) . The first number indicates the octane rating of the fuel tested to " aviation lean " standards, which
6832-544: The United States. Swift Fuels has an agreement for distribution in Europe. UL94 is not intended to be a full replacement for 100LL, but rather is designed to be a drop-in replacement for aircraft with lower-octane-rated engines, such as those that are approved for operation on Grade 80 avgas (or lower), UL91, or mogas. It is estimated that up to 65% of the fleet of current general aviation piston-engine-powered aircraft can operate on UL94 with no modifications to either
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#17327728941176944-574: The Wankel engine has been used in motor gliders where the compactness, light weight, and smoothness are crucially important. The now-defunct Staverton-based firm MidWest designed and produced single- and twin-rotor aero engines, the MidWest AE series . These engines were developed from the motor in the Norton Classic motorcycle . The twin-rotor version was fitted into ARV Super2s and
7056-454: The airframe with different engine cowling and exhaust arrangements are applicable for the automotive fuel STC, and even then require fuel-system modifications. Vapor lock typically occurs in fuel systems where a mechanically-driven fuel pump mounted on the engine draws fuel from a tank mounted lower than the pump. The reduced pressure in the line can cause the more volatile components in automotive gasoline to flash into vapor, forming bubbles in
7168-405: The alloys used in aviation engine construction are chosen for their durability and synergistic relationship with the protective features of lead, and engine wear in the valves is a potential problem on automotive gasoline conversions. Fortunately, significant history of engines converted to mogas has shown that very few engine problems are caused by automotive gasoline . A larger problem stems from
7280-464: The aviation industry will be "forced out" of using 100LL in the near future, leaving automotive fuel and jet fuel as the only alternatives. In May 2010, TCM announced that they had licensed development of the SMA SR305 diesel engine. In November 2008, National Air Transportation Association president Jim Coyne indicated that the environmental impact of aviation is expected to be a big issue over
7392-734: The company introduce the 37 hp (28 kW) A-40 four-cylinder engine. A follow-on design, the 50 hp (37 kW) A-50 was introduced in 1938 and was used to power the Taylor Cub and derivative Piper Cub . As the Second World War started in 1939 Continental commenced building aircraft engines for use in British and American tanks. Continental formed Continental Aviation and Engineering (CAE) in 1940 to develop and produce aircraft engines of over 500 hp (373 kW). Continental ranked 38th among United States corporations in
7504-531: The company was very concerned about future availability of 100LL avgas and as a result would develop a diesel engine in the 300 hp (220 kW) range for certification in 2009 or 2010. By the fall of 2009 the company was feeling the effects of the economic situation and the resulting reduced demand for aircraft engines. The company announced that it would close its plant for two one-week periods in October 2009 and January 2010. Salaried employees would move to
7616-500: The compression-ignition diesel engine is seldom used. Starting in the 1930s attempts were made to produce a practical aircraft diesel engine . In general, Diesel engines are more reliable and much better suited to running for long periods of time at medium power settings. The lightweight alloys of the 1930s were not up to the task of handling the much higher compression ratios of diesel engines, so they generally had poor power-to-weight ratios and were uncommon for that reason, although
7728-593: The cylinders arranged evenly around the crankshaft, although some early engines, sometimes called semi-radials or fan configuration engines, had an uneven arrangement. The best known engine of this type is the Anzani engine, which was fitted to the Bleriot XI used for the first flight across the English Channel in 1909. This arrangement had the drawback of needing a heavy counterbalance for the crankshaft, but
7840-486: The cylinders in a circle around the crankcase, as in a radial engine, (see above), but the crankshaft is fixed to the airframe and the propeller is fixed to the engine case, so that the crankcase and cylinders rotate. The advantage of this arrangement is that a satisfactory flow of cooling air is maintained even at low airspeeds, retaining the weight advantage and simplicity of a conventional air-cooled engine without one of their major drawbacks. The first practical rotary engine
7952-572: The decision to pursue 94UL as a mistake that could cost the aviation industry billions in lost business. Lycoming believes the industry should be pursuing 100UL instead. The Lycoming position is supported by aircraft type clubs representing owners of aircraft that would be unable to run on lower octane fuel. In June 2010, clubs such as the American Bonanza Society, the Malibu Mirage Owners and Pilots Association, and
8064-581: The engine core is the bypass ratio. Low-bypass engines are preferred for military applications such as fighters due to high thrust-to-weight ratio, while high-bypass engines are preferred for civil use for good fuel efficiency and low noise. High-bypass turbofans are usually most efficient when the aircraft is traveling at 500 to 550 miles per hour (800 to 890 kilometres per hour), the cruise speed of most large airliners. Low-bypass turbofans can reach supersonic speeds, though normally only when fitted with afterburners . The term advanced technology engine refers to
8176-413: The engine or airframe. Some aircraft, however, do require a FAA -approved Supplemental Type Certificate (STC) to be purchased to allow for operation on UL94. UL94 has a minimum Motor octane number (MON, which is the octane rating employed for grading aviation gasoline) of 94.0. 100LL has a minimum MON of 99.6. AKI is the octane rating used to grade all U.S. automotive gasoline (typical values at
8288-438: The engine works by having a coiled pipe in the combustion chamber that superheats the fuel (propane) before being injected into the air-fuel inlet. In the combustion chamber, the fuel/air mixture ignites and burns, creating thrust as it leaves through the exhaust pipe. Induction and compression of the fuel/air mixture is done both by the pressure of propane as it is injected, along with the sound waves created by combustion acting on
8400-415: The engine's heat-radiating surfaces to the air and tends to cancel reciprocating forces, radials tend to cool evenly and run smoothly. The lower cylinders, which are under the crankcase, may collect oil when the engine has been stopped for an extended period. If this oil is not cleared from the cylinders prior to starting the engine, serious damage due to hydrostatic lock may occur. Most radial engines have
8512-538: The ethanol can attack materials in aircraft construction which pre-date "gasahol" fuels. Most of these applicable aircraft have low-compression engines which were originally certified to run on 80/87 avgas and require only "regular" 87 anti-knock index automotive gasoline. Examples include the popular Cessna 172 Skyhawk or Piper Cherokee with the 150 hp (110 kW) variant of the Lycoming O-320 . Some aircraft engines were originally certified using
8624-402: The exception of a lower motor octane number (94.0 minimum for UL94 vs. 99.6 minimum for 100LL) and a decreased maximum lead content. UL94 is an unleaded fuel, but as with all ASTM International unleaded gasoline specifications, a de minimis amount of unintentionally added lead is permitted. Since May 2016, UL94, now a product of Swift Fuels, is available for sale at dozens of airports in
8736-606: The first electric aircraft engine to be awarded a type certificate by EASA for use in general aviation . The E-811 powers the Pipistrel Velis Electro . Limited experiments with solar electric propulsion have been performed, notably the manned Solar Challenger and Solar Impulse and the unmanned NASA Pathfinder aircraft. Many big companies, such as Siemens, are developing high performance electric engines for aircraft use, also, SAE shows new developments in elements as pure Copper core electric motors with
8848-399: The first engines to use multiple spools —concentric shafts that are free to rotate at their own speed—to let the engine react more quickly to changing power requirements. Turbofans are coarsely split into low-bypass and high-bypass categories. Bypass air flows through the fan, but around the jet core, not mixing with fuel and burning. The ratio of this air to the amount of air flowing through
8960-572: The fuel from renewable biomass feedstocks, and aims to produce something competitive in price with 100LL and currently available alternative fuels. Swift Fuels has suggested that the fuel, formerly referred to as 100SF, will be available for "high performance piston-powered aircraft" before 2020. John and Mary-Louise Rusek founded Swift Enterprises in 2001 to develop renewable fuels and hydrogen fuel cells. They began testing "Swift 142" in 2006 and patented several alternatives for non-alcohol based fuels which can be derived from biomass fermentation . Over
9072-524: The fuel line and interrupting fuel flow. If an electric boost pump is mounted in the fuel tank to push fuel toward the engine, as is common practice in fuel-injected automobiles, the fuel pressure in the lines is maintained above ambient pressure, preventing bubble formation. Likewise, if the fuel tank is mounted above the engine and fuel flows primarily due to gravity, as in a high-wing airplane, vapor lock cannot occur, using either aviation or automotive fuels. Fuel-injected engines in automobiles also usually have
9184-400: The fuel system can use up to 10% ethanol. Fuel dyes aid ground crew and pilots in identifying and distinguishing the fuel grades and most are specified by ASTM D910 or other standards. Dyes for the fuel are required in some countries. The 100LL phase-out has been called "one of modern GA's most pressing problems", because 70% of 100LL aviation fuel is used by the 30% of the aircraft in
9296-487: The fuel system, ensuring adequate shielding from high temperatures and maintaining sufficient pressure in the fuel lines. This is the main reason why both the specific engine model as well as the aircraft in which it is installed must be supplementally certified for the conversion. A good example of this is the Piper Cherokee with high-compression 160 or 180 hp (120 or 130 kW) engines. Only later versions of
9408-446: The fuel to the required octane rating is used; actual concentrations are often lower than the permissible maximum. Historically, many post-WWII developed, low-powered 4- and 6-cylinder piston aircraft engines were designed to use leaded fuels; an unleaded replacement fuel is being developed and certified for these engines. Some reciprocating-engine aircraft still require leaded fuels, but some do not, and some can burn unleaded gasoline if
9520-474: The general aviation fleet that cannot use any of the existing alternatives. There are three fundamental issues in using unleaded fuels without serious modification of the airframe/engine: In February 2008, Teledyne Continental Motors (TCM) announced that the company is very concerned about future availability of 100LL, and as a result, they would develop a line of diesel engines . In a February 2008 interview, TCM president Rhett Ross indicated belief that
9632-436: The higher and wider range of allowable vapor pressures found in automotive gasoline; this can pose some risk to aviation users if fuel system design considerations are not taken into account. Automotive gasoline can vaporize in fuel lines, causing a vapor lock (a bubble in the line) or fuel pump cavitation, thereby starving the engine of fuel. This does not constitute an insurmountable obstacle, but merely requires examination of
9744-497: The intake stacks. It was intended as a power plant for personal helicopters and compact aircraft such as Microlights. A few aircraft have used rocket engines for main thrust or attitude control, notably the Bell X-1 and North American X-15 . Rocket engines are not used for most aircraft as the energy and propellant efficiency is very poor, but have been employed for short bursts of speed and takeoff. Where fuel/propellant efficiency
9856-555: The interim CEO and chief financial officer (CFO). Aircraft engine In commercial aviation the major Western manufacturers of turbofan engines are Pratt & Whitney (a subsidiary of Raytheon Technologies ), General Electric , Rolls-Royce , and CFM International (a joint venture of Safran Aircraft Engines and General Electric). Russian manufacturers include the United Engine Corporation , Aviadvigatel and Klimov . Aeroengine Corporation of China
9968-560: The lack of lead with cylinder performance deteriorating to unacceptable levels in under 10 hours." In 2022, TCM changed its policy. They have announced a formal application to the FAA to approve the use of UL91 and UL94 in selected engines, stating that "Continental considers 91UL and 94UL fuel as a transitional step in a long-term strategy to reach a more sustainable aviation". Hjelmco Oil first introduced unleaded Avgas grades in Europe in 2003, after its success with 80UL. This grade of Avgas
10080-662: The lower-powered (100–150 horsepower or 75–112 kilowatts) aviation engines that were developed in the late 1990s are designed to run on unleaded fuel and on 100LL, an example being the Rotax 912 . Automotive gasoline – known as mogas or autogas among aviators – that does not contain ethanol may be used in certified aircraft that have a Supplemental Type Certificate (STC) for automotive gasoline, as well as in experimental aircraft and ultralight aircraft . Some oxygenates other than ethanol are approved, but these STC's prohibit ethanol-laced gasolines. Ethanol-treated gasoline
10192-430: The many limitations of the rotary engine so when the static style engines became more reliable and gave better specific weights and fuel consumption, the days of the rotary engine were numbered. The Wankel is a type of rotary engine. The Wankel engine is about one half the weight and size of a traditional four-stroke cycle piston engine of equal power output, and much lower in complexity. In an aircraft application,
10304-548: The merger reduced third-party manufacturers of Continental engine rebuild parts. ECi's Titan engines were modern non-certified engines competing with Lycoming's Thunderbolt. These were eventually rebranded as the Continental Titan. In March 2019 the company name was changed from Continental Motors, Inc. to Continental Aerospace Technologies . In March 2022, Karen Hong was named as the company's president and CEO, replacing Robert Stoppek. Hong had previously served as
10416-460: The models approved for UL94. Swift Fuels, LLC, has attained approval to produce fuel for testing at its pilot plant in Indiana. Composed of approximately 85% mesitylene and 15% isopentane , the fuel is reportedly scheduled for extensive testing by the FAA to receive certification under the new ASTM D7719 guideline for unleaded 100LL replacement fuels. The company eventually intends to produce
10528-433: The modern generation of jet engines. The principle is that a turbine engine will function more efficiently if the various sets of turbines can revolve at their individual optimum speeds, instead of at the same speed. The true advanced technology engine has a triple spool, meaning that instead of having a single drive shaft, there are three, in order that the three sets of blades may revolve at different speeds. An interim state
10640-463: The most common Avgas is 100LL. This refers to the octane rating (100 octane) and the lead content (LL = low lead, relative to the historic levels of lead in pre-regulation Avgas). Refineries blend Avgas with tetraethyllead (TEL) to achieve these high octane ratings, a practice that governments no longer permit for gasoline intended for road vehicles. The shrinking supply of TEL and the possibility of environmental legislation banning its use have made
10752-404: The new AE300 turbodiesel , also based on a Mercedes engine. Competing new Diesel engines may bring fuel efficiency and lead-free emissions to small aircraft, representing the biggest change in light aircraft engines in decades. While military fighters require very high speeds, many civil airplanes do not. Yet, civil aircraft designers wanted to benefit from the high power and low maintenance that
10864-559: The next few years and will result in the phasing out of 100LL because of its lead content. By May 2012, the US Federal Aviation Administration (FAA Unleaded Avgas Transition rulemaking committee) had put together a plan in conjunction with industry to replace leaded avgas with an unleaded alternative within 11 years. Given the progress already made on 100SF and G100UL, the replacement time might be shorter than that 2023 estimate. Each candidate fuel must meet
10976-483: The point of view of the pilot looking forward, so for example on a four-engine aircraft such as the Boeing 747 , engine No. 1 is on the left side, farthest from the fuselage, while engine No. 3 is on the right side nearest to the fuselage. In the case of the twin-engine English Electric Lightning , which has two fuselage-mounted jet engines one above the other, engine No. 1 is below and to the front of engine No. 2, which
11088-432: The power-to-weight ratio is very important, making the Wankel engine a good choice. Because the engine is typically constructed with an aluminium housing and a steel rotor, and aluminium expands more than steel when heated, a Wankel engine does not seize when overheated, unlike a piston engine. This is an important safety factor for aeronautical use. Considerable development of these designs started after World War II , but at
11200-466: The pump can include 87, 89, 91, and 93), and also the 93UL fuel from Airworthy AutoGas. The minimum AKI of UL94, as sold by Swift Fuels, is 98.0. Concurrent with the addition of UL94 to ASTM D7547, the FAA published Special Airworthiness Information Bulletin (SAIB) HQ-16-05, which states that "UL94 meets the operating limitations or aircraft and engines approved to operate with grade UL91 avgas," meaning that "Grade UL94 avgas that meets specification D7547
11312-427: The rich settings used for take-off and other full-power conditions. Antiknock agents such as tetraethyl lead (TEL) help to control detonation and provide lubrication. One gram of TEL contains 640.6 milligrams of lead . ("avgas 100") ("avgas 100LL") ("avgas 115") 100LL (pronounced "one hundred low lead") may contain a maximum of one-half the tetraethyllead allowed in 100/130 (green) avgas. Some of
11424-683: The same as when they were first developed in the 1940s, and were used in airline and military aero engines with high levels of supercharging ; notably the Rolls-Royce Merlin engine used in the Spitfire and Hurricane fighters, Mosquito fighter-bomber and Lancaster heavy bomber (the Merlin II and later versions required 100-octane fuel), as well as the liquid-cooled Allison V-1710 engine, and air-cooled radial engines from Pratt & Whitney, Wright, and other manufacturers on both sides of
11536-439: The time the aircraft industry favored the use of turbine engines. It was believed that turbojet or turboprop engines could power all aircraft, from the largest to smallest designs. The Wankel engine did not find many applications in aircraft, but was used by Mazda in a popular line of sports cars . The French company Citroën had developed Wankel powered RE-2 [ fr ] helicopter in 1970's. In modern times
11648-414: The two crankshafts geared together. This type of engine has one or more rows of cylinders arranged around a centrally located crankcase . Each row generally has an odd number of cylinders to produce smooth operation. A radial engine has only one crank throw per row and a relatively small crankcase, resulting in a favorable power-to-weight ratio . Because the cylinder arrangement exposes a large amount of
11760-409: The use of a glow plug ) powered by glow fuel , a mixture of methanol , nitromethane , and lubricant. Electrically powered model airplanes and helicopters are also commercially available. Small multicopter UAVs are almost always powered by electricity, but larger gasoline-powered designs are under development. Avgas Avgas ( aviation gasoline , also known as aviation spirit in
11872-537: The value of wartime production contracts. During the late 1930s, early 1940s the Gray Marine Motor Company adapted Continental engines for maritime use. On 14 June 1944 the company was purchased by Continental for US$ 2.6 million. John W. Mulford, the son of one of Gray's founders was appointed general manager of Gray by Continental. Gray's continued to make marine engines in the post-war period until its closure by Continental in about 1967. During
11984-399: The years after the war, the drawbacks of the turbojet gradually became apparent. Below about Mach 2, turbojets are very fuel inefficient and create tremendous amounts of noise. Early designs also respond very slowly to power changes, a fact that killed many experienced pilots when they attempted the transition to jets. These drawbacks eventually led to the downfall of the pure turbojet, and only
12096-400: Was developed as essentially automotive gasoline with additional quality tracking and restrictions on permissible additives. This fuel is not currently in production and no refiners have committed to producing it. Rotax allows up to 10% ethanol (similar to E10 fuel for cars) in the fuel for Rotax 912 engines. Light sport aircraft that are specified by the manufacturer to tolerate alcohol in
12208-486: Was formed in 2016 with the merger of several smaller companies. The largest manufacturer of turboprop engines for general aviation is Pratt & Whitney. General Electric announced in 2015 entrance into the market. In this section, for clarity, the term "inline engine" refers only to engines with a single row of cylinders, as used in automotive language, but in aviation terms, the phrase "inline engine" also covers V-type and opposed engines (as described below), and
12320-572: Was the Gnome Omega designed by the Seguin brothers and first flown in 1909. Its relative reliability and good power to weight ratio changed aviation dramatically. Before the first World War most speed records were gained using Gnome-engined aircraft, and in the early years of the war rotary engines were dominant in aircraft types for which speed and agility were paramount. To increase power, engines with two rows of cylinders were built. However,
12432-479: Was the German unmanned V1 flying bomb of World War II . Though the same engines were also used experimentally for ersatz fighter aircraft, the extremely loud noise generated by the engines caused mechanical damage to the airframe that was sufficient to make the idea unworkable. The Gluhareff Pressure Jet (or tip jet) is a type of jet engine that, like a valveless pulsejet, has no moving parts. Having no moving parts,
12544-487: Was used to avoid the spark plugs oiling up. In military aircraft designs, the large frontal area of the engine acted as an extra layer of armor for the pilot. Also air-cooled engines, without vulnerable radiators, are slightly less prone to battle damage, and on occasion would continue running even with one or more cylinders shot away. However, the large frontal area also resulted in an aircraft with an aerodynamically inefficient increased frontal area. Rotary engines have
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