We pilots love engines and with good reason. We rely on their continued trouble-free operation to keep us flying safely. Perhaps more to the point, without engines, flight would never have gone far, and it can be argued that every noteworthy advance in aircraft performance was preceded by a noteworthy advance in power-plant design.
There was a lot of work to be done. The Wright Flyer of 1903, the first powered aircraft, was equipped with a 12 hp engine that was barely powerful enough to get the airplane airborne, even with the help of a swift breeze and a takeoff run on rails. Today, solid-fuel rocket engines are capable of producing more than 2 million pounds of thrust, allowing us to send huge payloads into space. Even in terrestrial applications there continues to be much propulsion progress, from the refinement of existing engines with much greater efficiency and lower noise levels to whole new concepts, such as the NASA-funded hypersonic scramjet project. Here are our picks for the top 50 engines of all time to emerge from the march of power-plant evolution.
Get exclusive online content like this delivered straight to your inbox by . signing up for our free enewsletter The Wright-Double Cyclone took radial piston engine technology to its very limits, essentially mating two already powerful Wright Cyclone 9-cylinder engines into an 18-cylinder twin-row powerhouse. In one modern application — the highly modified Grumman Bearcat Reno racer Rare Bear — the two-plus ton dry weight engine can produce as much as 4,000 horsepower, though typical power output was around a third of that. Wright had begun developing the engine in the mid-1930s, but it wasn’t until the need for an ultra-long range and high altitude bomber, the Boeing B-29, came to pass that Wright completed the engine. After a lot of work to improve its reliability, the 3350 would go on to power not only the Superfortress but a number of the most influential early airliners, including the Lockheed Constellation and Super Constellation and the Douglas DC-7. We asked Flying readers to help us add one more engine to the list and the Wright 3350 Double-Cyclone came out on top. View our reader’s choice gallery here to check out the other contenders. Hungarian engineer György Jendrassik designed the Jendrassik Cs-1, the first functional turboprop engine, in the 1930s. The engine was intended for the Hungarian twin-engine Varga RMI-1 reconnaissance bomber. Jendrassik’s goal of producing a 1,000 hp engine was cut short by issues with combustion stability that limited the first version to 400 horsepower. The Hungarian Air Force ultimately gave up on Jendrassik’s efforts, and the RMI-1 was instead outfitted with Daimler-Benz DB 605 engines. Based on the power plant used in the iconic Porsche 911 sports car, the six-cylinder Porsche PFM 3200 emerged in the 1980s as a smoother, simpler and more reliable alternative to traditional general aviation piston engines. The PFM appeared in a handful of airplanes but debuted in only one production airplane: the Mooney PFM, of which a few dozen were produced. With the PFM, which relied on a dual electronic ignition system, the need to manipulate mixture and prop revolutions per minute settings in flight disappeared, and in its place came a single power lever that ensured the engine operated at its most efficient setting without any extra work by the pilot. In addition to this reduced cockpit workload was an incredibly serene flying experience void of the traditional vibrations of a typical piston workhorse. Despite its great fuel efficiency and ease of operation, its pitfalls — heavier weight, lack of increased performance and faulty gearbox — held the engine back from further prominence. But that didn’t prevent its lasting impression on those pilots lucky enough to experience its smooth flying characteristics for themselves. Bergfalke2 via Wikipedia Alessandro Anzani, an Italian who later moved to France, started out building motorcycle engines in the early 1900s and was inspired to start designing airplane engines after the Wright brothers visited France. He designed a series of three-cylinder engines that produced anywhere from 10 to 50 hp, including the 25 hp engine that powered Louis Bleriot’s XI airplane across the English Channel in 1909. Anzani’s air-cooled engines featured cast iron cylinders that were initially arranged in a fan shape. But the weight penalty and increased noise of the fan arrangement used for the three-cylinder engines forced Anzani to rearrange his design into a Y-shaped radial engine. Alf van Beem The GEnx was part of General Electric’s so-called “ecomagination” initiative to save customers money while helping the environment. The resulting engine is the technological marvel that powers the Boeing 787 Dreamliner as well as the Boeing 747-8. Featuring composite fan blades, the engine delivers 15 percent better fuel consumption than previous generation turbofans for big airliners while employing a new type of combustor that reduces nitrous oxide by more than 50 percent below regulatory limits. Developed from the GE90 engine, the GEnx also claims to be the quietest commercial jet engine ever produced thanks to large, more efficient fan blades that operate at lower tip speeds. Courtesy of GE The Gnome-Rhone Mistral Major, also known as the 14K, was a two-row radial engine that was, for a time, the most powerful engine ordered in large numbers on the planet. Developed in the late 1920s, the air-cooled Mistral Major was part of the French manufacturer’s popular K series and the descendant of the smaller Gnome-Rhone 7K. Fighter variants of the 14K were rated at 900 hp, surpassing the outputs of most other European engines at the time and ensuring the Mistral Major’s appeal both on the continent and beyond. A testament to its success, the engine was used in more than a dozen different airplane types and spawned a large number of variants. U.S. Federal Government The Rocketdyne F-1 was developed in the 1950s to power the United States’ burgeoning space program. Despite its relative antiquity, the F-1 remains the most powerful liquid-fuel propulsion system ever built, putting out 1.5 million pounds of thrust. Five F-1s were used for each Saturn V launch, with each engine burning more than 400 gallons of liquid oxygen per second, approximately 5,000 times the amount of a high-powered jet engine used on commercial airliners today. The F-1 was a critical component to NASA’s successful space launches in the 1960s, leading to the famous lunar mission of Apollo 11 in 1969. What does it take to make an airplane go 7,000 mph? As the world-record flight of NASA’s X-43 proved in 2004, the answer is supersonic combustion ramjet, or scramjet, technology. In development since World War II, scramjet technology allows ultrahigh-speed aircraft traveling faster than Mach 4 to get their oxygen straight from the atmosphere, as opposed to relying on an on-board supply of heavy oxidizer or a traditional turbine engine. This provides several advantages, including lighter weight, better performance and improved safety. While a traditional rocket booster or jet engine is still needed to get the aircraft to Mach 4 before its forward speed is able to compress the oxygen of the atmosphere without additional help, the technology widely expands the potential for ultrahigh-speed flights. Researchers say scramjet technology could someday help aircraft go as much as 15 times the speed of sound, turning a traditional 18-hour flight from New York City to Tokyo into a two-hour jaunt. No one knows your factory engine better than the factory that built it in the first place. Visit www.Lycoming.com to find your local distributor. Competing with the Pratt & Whitney PT6A, one of the most successful engines ever produced, is no small task. But the 800 shaft horsepower General Electric H80 engine is giving a good go of it. Introduced in the highly respected Thrush 510G crop-duster, the H80 was developed out of Walter Aircraft Engines’ M601 after GE acquired the Czech company in 2008. While now American-owned, the H80 is still produced in the Czech Republic and was first certified by European Aviation Safety Agency in December 2011. FAA certification was achieved a few months later. With a successful introduction, the H80 has been STC’d for the King Air C90 and will power Nextant’s modified version of the twin-turboprop, the G90XT. Courtesy of GE Franklin Engine Company’s six-cylinder engine series has been highly successful in both airplanes and helicopters. Thousands of aircraft have been powered by the Franklin, including Bell, Socata, Maule, Bellanca, Piper, Aeronca and Taylorcraft models to name a few. A 220 hp version of the engine received an STC for the Cessna 170, 172 and 175, turning hundreds of these popular airplanes into 182 performers. Franklin’s six-cylinder engines were produced from the 1940s to the 1970s by the Syracuse, New York-based company, which was an outgrowth of the Franklin Automobile Company. The engines were known for their reliability and for having very few airworthiness directives, but the company went bankrupt several times, and in 1975, the drawings for the engines were bought by a Polish company that still provides parts support today and hopes to restart production at some point. The Curtiss OX-5 V-8 aircraft engine has gone down in aviation lore as a legendary power plant. Curtiss introduced the OX-5 in 1910, and it soon found its way into the JN-4 Jenny, another Curtiss product. Over the next decade, Curtiss built more than 12,000 of these pretty V8s, which were capable of producing 90 hp and had a well-earned reputation for giving up the ghost at the worst possible moment because, the consensus is, their overhead valves required constant maintenance. Still, the OX-5 set the stage for the great V8 and V12 piston engines of the World War II era. Courtesy of John Fowler The Rolls-Royce Trent family of turbofan engines featuring advanced compressor and turbine blisk technology power a variety of current airliners, including the Airbus A330, A340 and A380, and the Boeing 777 and 787. The engine has been improved over the years with successive generations offering even better performance and efficiency. Today, the ultraquiet and efficient Trent 900 powers the A380 while the Trent 1000 is an available choice (along with the General Electric GEnx) on the 787. The Trent family led directly to Rolls-Royce’s huge success in the commercial propulsion market. The newest version of the engine, the Trent TEN (standing for Thrust, Efficiency and New technology), delivers 3 percent better specific fual consumption than the original and is designed to fly on all versions of the 787. As with nearly every new segment of aviation since the dawn of manned flight, the march of progress of ultralights (very light, single-seat, slow-moving aircraft) was a function of available propulsion technology. The design of truly useful models was limited by the availability of light, lower powered reliable engines. Rotax, which built engines for a number of specialty markets, including motorcycles, watercraft and snowmobiles, came to the rescue the lineup of light, inexpensive and relatively reliable two-stroke engines. The single-cylinder two-stroke model 277, an early Rotax aircraft engine, put out 26 hp, weighed just 65 pounds with reduction drive and exhaust, and cost just over $1,000. From 1975 through today, Rotax has produced more than 170,000 aircraft engines, most of them two-stroke lightweight models. From the 277, Rotax progressed to building ever more capable and powerful models, including the popular 447 and 503 models up to the 582, one of the most technologically advanced two-stroke engines, with rotary valves, oil injection, dual carbs and electronic ignition. The 582, which is still in production today, powers many dozens of light-aircraft models. The four-cylinder SR305-230 diesel engine was developed by French company SMA, which is now a subsidiary of Safran. The engine was first flown in 1998 on the French airframe Socata TB-20 and FAA certified in 2002. Recently, the SR305-230 was chosen to power Cessna’s latest version of the immensely popular Cessna 182 Skylane — the Turbo Skylane JT-A. The engine is air- and oil-cooled and compatible with jet-A, which is widely available at airports around the world. In addition to eliminating the growing concern of 100LL availability, the SR305 has an electronic control unit that optimizes the performance of the engine in all phases of ground and flight operations, reducing the workload for the pilot. SMA claims the operating cost of the SR305 is reduced by about 40 percent compared with avgas engines because of its longer 2,400 TBO, reduced number of parts and lower fuel consumption. The Ranger L-440 was a family of inverted, inline six-cylinder engines built in the 1930s and 1940s by the Ranger Aircraft Engine Division of Fairchild. Four versions of the L-440 were produced, putting out between 145 and 200 hp. The engine most famously powered the Fairchild PT-19 primary trainer. In all, more than 15,000 L-440 engines were built. After World War II, surplus Ranger engines found a ready home under the hoods of dirt track race cars and dragsters in the 1950s. The engine was prized for its light weight and simplicity, but the U.S. government sold surplus Ranger engines at such low prices that it put the company out of business. Courtesy of Aircraft Engine Historical Society The Hispano-Suiza 12Y was a world-class French engine that might have left a bigger historical impression were it not for Germany’s occupation of the country in World War II. The 12Y emerged as the engine of choice for many famed airplanes, including France’s Morane-Saulnier M.S.406 and Dewoitine 506 fighters, which tangled with the Luftwaffe in the Battle of France. The 12-cylinder, water-cooled 12Y was less powerful than contemporary engines from Daimler-Benz, but it was quite a bit lighter. In fact, the Y12’s biggest contribution in World War II came not from the French but from the Soviets, who produced versions under license of up to 1,100 hp that were used to power Yakovlev and Lavochkin fighters. Pline via Wikipedia Unlike most familiar engines that move a crankshaft to drive a propeller, the Gnome Rotary was designed with a stationary crankshaft around which the cylinders, crankcase and propeller spun. Two brothers, Laurent and Louis Seguin, came up with the idea, and their Societe des Moteurs Gnome engine was unveiled at the Paris Air Show in 1908. Developed in a range from 50 to 160 hp, Gnome engines were widely used in World War I airplanes. Generally, a lower number of moving parts is preferable when it comes to engines, and rotary engines did not stand the test of time. One of the biggest complaints from pilots over the past few decades is that aircraft engine technology lags far behind that of auto engines. In the mid-1990s, Continental worked to change that impression with its IOF-240 engine. The “F” in IOF-240 stands for full-authority digital engine control, or fadec, which is a fancy way of saying the engine automatically handles many of the chores — such as prop revolutions per minute, spark advance and fuel-air ratio — that are either fixed or controlled mechanically by the pilot in most light-plane applications. When introduced in 2002, the engine was rare in that it had neither magnetos nor mixture control. Instead, the ignition and fuel flow are controlled electronically. In addition to providing the optimal fuel/air mixture — the IOF-240 burns about 5 gallons per hour — the electronic system allows for more accurate engine analysis and troubleshooting. The IOF-240 was first introduced in the Liberty XL2, a two-seat carbon fiber airplane developed from the Europa kit airplane, which became the first piston-engine airplane certified with fadec. Courtesy of Continental No one knows your factory engine better than the factory that built it in the first place. Visit www.Lycoming.com to find your local distributor. When it hit the market in the late 1990s, the Thielert turbodiesel engine promised a true revolution. An extensive reworking of a high-tech German auto engine, the Centurion seemed to offer it all: a power-to-weight ratio competitive with gas piston engines, the ability to run on jet-A fuel, turbocharging and otherworldly fuel efficiency. Diamond Aircraft was the original adopter, designing the next-gen light twin TwinStar seemingly around the engines. Sadly, gearbox problems — the engine uses a reduction drive to get the prop speed down to useful revolutions per minute ranges — plagued the engine, with unacceptably short overhaul intervals and sky-high maintenance costs. Today, the Thielert engine is owned by Continental Motors, which has worked hard to improve the engine’s value proposition while reintroducing it in new and retrofit applications. Counted among the most successful radial engines ever produced, the Continental R-670 is famed for powering one of the most iconic military trainers of all time, the PT-17 Stearman biplane. The seven-cylinder, 220 hp engine was Continental’s second try at a radial engine, and it proved a runaway success though many consider it a bit underpowered. The manufacturer built more than 40,000 R-670s before and during World War II – and not just for aviation uses. In addition to powering several airplane types of the day, the R-670 was also fitted in a number of light armored vehicles during the war, including the M3 Stuart tank. Nimbus227 via Wikipedia The sound of a Garrett-Honeywell TPE331 idling on the ramp is unmistakable. The direct-drive 331 started out as a helicopter engine but soon found favor with turboprop manufacturers, who prized the engine for its economy and good fuel-to-weight ratio. The best known airplane to obtain its power from the TPE331 was the Mitsubishi MU-2, which is perhaps the most instantly recognizable of TPE331-powered airplanes for the high-pitched whine of the constant-speed engine at idle. Other airplanes that have used the engine include the Jetstream 31, Cessna 441, Pilatus PC-6 Turbo Porter, Piper Cheyenne 400 and many others. Today, the TPE331 line is owned and maintained by Honeywell. As had been done by other manufacturers — sometimes to good effect — Lycoming expanded the horsepower range of its four-cylinder aircraft engines by adding another pair of opposed jugs, creating a six-cylinder engine with 50 percent more potential power. The 540 series engines got their start in 1957 as new larger personal and charter airplanes pressed the need for more power. Piper made great use of the engine, most notably in its Navajo lineup, PA-32s, Aztecs, Comanches and Mirages, but numerous other manufacturers opted for 540-power as well, including Aero Commander, Pitts and Robinson Helicopter’s R44. As with the four-cylinder version, the 540 is available in a variety of models, with turbocharging a popular option. As the United States entered World War I in 1917, the government needed a powerful, mass-produced engine to equip the nation’s aircraft fleet. It enlisted automobile producers to lead the charge, and a design solution was produced in just five days. The first Liberty engine prototype was a water-cooled, eight-cylinder L-8, but it was soon passed over to make way for production of the more powerful V12 Liberty. Production of the engine revolved around the use of standard parts, but the manufacturers of the Liberty L-12 — Lincoln, Packard Motor Car, Ford Motor, Nordyke & Marmon and General Motors — all initially struggled to acclimate the creation of the engine to the same type of efficient mass production that had taken the automobile industry by storm. But as the war went on, initial hiccups were overcome leading to the production of more than 13,500 L-12s by the war’s end and more than 20,000 engines in the L-12’s production lifetime. The engine powered a variety of aircraft, including the de Havilland DH-4, Fokker T2, Navy Curtiss NC-4 and the Douglas World Cruiser, among others. Courtesy of John Fowler As aircraft designers pursued the dream of a very light jet in the late ’90s and early 2000s, one necessary aspect remained elusive: a workable engine. While other attempts developed at the time flopped, the PW600 series made the idea of a personal light jet a feasible reality. Built using half the components of a conventional turbofan, the PW600 provided a lightweight, compact, easy-to-maintain engine that could produce enough power to help this new class of bizjets meet FAA performance benchmarks. The PW600 family comes equipped with dual-channel full-authority digital engine control and includes engines that produce 950 to 1,750 pounds of thrust. Thanks to their reliability and proven performance, PW600 models can be found in a variety of light bizjets, including the Eclipse 550, the Cessna Mustang and the Embraer Phenom 100. Courtesy of Pratt & Whitney The first turbojet engine put into operation, the Junkers Jumo 004 was one of a few jet engines engineered by the Germans in the late 1930s and early 1940s to power early fighter jets in the quest to produce the ultimate fighter airplane. The Jumo 004 powered the twin-engine Messerschmitt Me 262, the first jet fighter put into operation during World War II. At 152 inches, the engines were almost as long as the Me 262’s fuselage and produced almost 2,000 pounds of thrust. Unfortunately, these early jet engines were notoriously unreliable. Their average service life was only about a dozen hours. NASA The Pratt & Whitney F119 is a technological beast that powers the world’s first — and for now, only — operational fifth-generation fighter. There’s no question it is among the most advanced production engines ever made. It combines stealth technology and vectored thrust to give the Lockheed Martin F-22 unprecedented maneuverability. The engine delivers 35,000 pounds of thrust, enough to power the F-22 to supersonic speeds without afterburner. In addition to the F-22, the F119 engine has been proposed for the Rockwell B1-R, a potential upgrade to the B1-B that would increase the bomber’s speed from Mach 1.25 to Mach 2.2. Courtesy of Pratt & Whitney The Pratt & Whitney R-1340 was the first of the legendary Wasp family of radial engines, which was heralded for its power and reliability. The single-row, nine-cylinder engine produced between 500 and 600 hp, depending on the version, and was perfect for the airplanes it powered beginning in 1925, from the Ford Trimotor to Jimmy Doolittle’s Gee Bee racer to the de Havilland Otter and more than 50 other airplane types. Probably the most famous R-1340-powered airplane was the modified Lockheed 10E Electra flown by Amelia Earhart on her ill-fated 1937 around-the-world record attempt. Sanjay Acharya via Wikipedia No one knows your factory engine better than the factory that built it in the first place. Visit www.Lycoming.com to find your local distributor. The six-cylinder, fuel-injected TSIO-550 is the turbocharged version of the IO-550, which was first introduced by Continental in 1983. Engines in the IO-550 series produce anywhere from 280 to 360 hp. In the 1990s, at Raytheon’s request, Continental tweaked the IO-550 to optimize the performance of the 300 hp engine that powers the Beechcraft Baron 58. The result was a smooth, reliable engine that was hard to beat in its class. With even better performance at higher altitude thanks to its dual turbochargers, the TSIO-550 powers the three top-performing modern-day single-engine certified piston airplanes: the Cessna TTx, Cirrus SR22 and Mooney Acclaim. Courtesy of Continental The supercharged Daimler-Benz DB 605 inverted V12 is famed for powering the Bf 109, one of the Luftwaffe’s most potent and feared fighters. The engine’s direct fuel injection gave the Bf 109 a distinct advantage over the British Spitfire when pulling negative Gs, allowing many pilots to escape bad situations and live to fight another day. Though prone to mechanical problems, the 35.7-liter, liquid-cooled DB 605 produced 1,455 hp, making it one of the most powerful fighter engines of World War II. Launched in the early 1950s, the Lycoming O-360 and subsequent IO-360 engines arguably became the prototypical engines in light general aviation, dominating — along with the company’s 320 and 540 series engines — a wide sector of piston-powered aviation. It’s hard to say for which platform the 360 series engines are best known, as they are standard equipment on dozens of fixed and rotary-winged aircraft, from the Piper Super Cub utility taildragger to the Robinson R22 helicopter to the Mooney 201, where the engine helped define the modern personal transportation airplane. The four-cylinder opposed piston engine has carbureted, fuel-injected, turbocharged, counter-rotating and acrobatic versions. It is still in production with numerous ongoing new aircraft applications, including in the Cessna 172. Those of us who have flown behind a Lycoming 360 know it for its reliability, consistent TBO performance and good fuel efficiency. Perhaps the best known engine of World War I was the French Le Rhone rotary, which was strangely enough developed in Germany for non-aviation applications shortly after the Wrights first flew. Rotary engines featured the entire bank of cylinders rotating around a stationary crankshaft. They were a powerful improvement on the state of the art, providing good amounts of horsepower at relatively light weights and with good cooling. They were an all-or-nothing affair, however — full power or none at all with the pilot intermittently turning the ignition, or parts of it, off and back on again — and they routinely sprayed pilots with castor oil as part of the experience. Because of the cross-border nature of technology even then, copies and licensed variants of the Le Rhone were used by both sides in the war, including in some of the most famous fighters of the day. Airplanes flying behind Le Rhone power included the Fokker Dr.I, the Sopwith Camel, the Nieuport 11 and the Bristol Scout. Over the course of just a few years, factories in several countries cranked out around 100,000 Le Rhones, making it one of the most produced aircraft engines in history. The General Electric J85 was originally developed to power a decoy drone that would protect B-52 bombers from incoming surface-to-air missiles. The military was soon making use of the small turbojet engine to power the Northrop T-38 Talon and F-5. The civilian version of the engine, the CJ610, became a mainstay of early corporate aviation in the first Lears and the Hansa Jet. Today the J85 powers Scaled Composites’ White Knight, the carrier airplane for SpaceShipOne. It has also been chosen for planned reproductions of the German Me 262 from an Everett, Washington, company. The U.S. Air Force plans to keep the engines in service through 2040, a testament to the J85’s longevity and durability. Courtesy of GE Originally a product of Garrett AiResearch and later AlliedSignal, the Honeywell TFE731 is one of the most successful civil turbofan engines ever, with more than 11,000 built since its introduction in 1972. Derived from the auxiliary power unit in the McDonnell Douglas DC-10, the TFE731 boasted low fuel consumption and less noise than previous jet engines, leading to its selection in the early 1970s for the Learjet 35/36 and Dassault Falcon 10. Since then, the engine has flown for more than 100 million flight hours in a variety of business jets, including various Cessna Citation models, the Dassault Falcon 50 and 900, the Hawker 800 and 900XP, the Learjet 40/45, the Gulfstream G150, and many others. Production of the engine is still going strong today, and it’s newest aircraft assignment is the Scorpion tactical jet from Textron AirLand. When Rotax introduced its model 912 engine almost two decades ago, it signaled a sea change in the sport-aviation game. With this technologically advanced four-stroke engine, sport-plane designers had the option of a higher-powered light engine with remarkable fuel efficiency and the kind of durability light-plane pilots had come to expect from a certified engine. Employed in a long list of sport aircraft starting in the early ’90s and stretching out to today, the 912 has powered certificated and homebuilt airplanes from Flight Design, RANS, Tecnam, Van’s and dozens of others. The four-stroke electronic ignition engine is air- and liquid-cooled with a very respectable 2,000-hour TBO. The original 80 hp 912 was carbureted, but today, models offer fuel injection in the 100 hp 912iS variant and turbocharging in the closely related 115 hp 914 product. The quiet hum of the six-cylinder, air-cooled Continental O-300 piston engine has been enjoyed in several popular airplane types, including the Globe Swift, Maule M-4 and the immensely popular Cessna 172 Skyhawk. The O-300 is an improved version of the C-145, a 145 hp engine introduced in 1947 and developed from the 125 hp C-125. Continental achieved a higher horsepower rating for the C-145/O-300 by increasing the crankshaft speed and the length of the piston stroke of the C-125. The O-300 became so successful that Rolls-Royce produced it in Europe under license from Continental. Rolls-Royce The Rolls-Royce BR700 family of turbofan engines single-handedly spawned the ultralong-range business jet segment, powering the Gulfstream V and Bombardier Global Express launched in the mid-1990s. Offering unparalleled efficiency, the BR710 provided range figures of 6,000 nm in the GV, which quickly became the gold standard of corporate jets. Originally a BMW/Rolls-Royce partnership, Rolls-Royce has since assumed full control of the program. The BR725, an even more efficient version of the engine, powers Gulfstream’s new flagship G650 to a max speed of Mach 0.925 and a range of 7,000 nm at Mach 0.85. jkb- via Wikipedia No one knows your factory engine better than the factory that built it in the first place. Visit www.Lycoming.com to find your local distributor. Launched in 1930, the Jacobs L-4 series engine is one of the most noteworthy radial engines of all time. It was first and foremost an excellent engine — reliable, smooth-running and relatively fuel-efficient to boot. Early on, the engine was nicknamed the “Shaky Jake” for its propensity to shake vigorously on its mounts when first started and only slightly less vigorously at low rpm, a trait that most pilots of Jacobs-powered airplanes find endearing to this day. The L-4, designated the R-755 by the military, was almost without question the most technologically advanced radial engine of its day, with forged aluminum pistons, sodium-filled exhaust valves and a magnesium alloy crankcase. The engine began life as a 225 hp model, but later versions produced up to 350 hp. Interestingly, a number of the many airplanes to get Jacobs power include a few of the most beautiful models ever, most notably the Beech Staggerwing, the Cessna 195 and a number of Waco cabin biplanes. The Jacobs L-4 and derivative engines were produced for more than 40 years until the early 1970s. While exact production numbers are hard to come by, the engines number at least 10,000 and were standard equipment in more than a dozen airplanes. Courtesy of Aircraft Engine Historical Society A modern marvel, the Space Shuttle’s reusable solid rocket motor was 126 feet long, 12 feet in diameter and produced an average thrust of 2.6 million pounds. With all that power, propellant accounted for about 85 percent of the 1.3 million pounds that made up the motor. Two RSRMs were required for a space shuttle launch, bringing the vessel to about 24 nautical miles of altitude and a speed of 3,000 miles per hour before detaching from the fuselage and returning to Earth by parachute. As the name implies, the RSRM was reusable, though it had to be cleaned, inspected and tested after each use. NASA Introduced by Williams International, a then-little-known manufacturer of cruise missile engines, the Williams FJ44 would become the epitome of modern light jet engine design. Popularized on the prolific Cessna CitationJet lineup, the FJ44 proved itself a reliable and efficient performer, to the point that improved versions boast nearly double the thrust rating of the original and have remained stellar performers in the category a quarter of a century after the engine’s introduction. Today, the FJ44 is almost synonymous with the light jet segment, with more installed applications than its competitors combined. British RAF officer Sir Frank Whittle is recognized as the father of the jet engine for his pioneering work before World War II. He is credited with single-handedly inventing the turbojet engine, which the RAF unfortunately failed to grasp as the revolutionary creation it was. Because the plans were never kept secret, German engineers easily reverse-engineered Whittle’s work. The breakthrough for Whittle had come in the late 1920s, when he realized how much more efficient it would be to use a turbine instead of a piston engine to compress the air in a jet engine. By 1940, Whittle formed a British company called Power Jets Limited to build an engine. The W.1 turbojet engine was soon a reality, powering the Gloster E.28 prototype, the first British jet airplane, on its first flight on May 15, 1941. Courtesy of Aircraft Engine Historical Society One of the most prolific piston engines of all time, the Wright Cyclone R-1820 was developed in the early 1930s as a descendent of the R-1750. At the beginning of its 25-year production run, the nine-cylinder R-1820 produced 575 hp. But various design enhancements over the years would eventually make the air-cooled radial engine a 1,525 hp workhorse. Thanks to its low maintenance and favorable weight-to-power ratio, the R-1820 was selected as the engine of choice for a wide variety of aircraft. It most famously powered the B-17 Flying Fortress but also laid claim to the DC-1, DC-2, early models of the DC-3, Grumman J2F Duck, Curtiss P-36 and many others. U.S. Air Force Pratt & Whitney’s R-2800, also called the Double Wasp for its twin-row arrangement, was an 18-cylinder, air-cooled engine with a 2,800-cubic-inch displacement. Capable of producing 2,000 hp, the Double Wasp was first run in 1937, introduced to the market in 1939 and employed in several famous warbirds, including the Vought F4U Corsair, Grumman F6F Hellcat and Republic P-47 Thunderbolt. The power was later increased to as much as 2,800 hp. After World War II the R-2800 continued as a popular power plant and was mounted to wings of the Douglas DC-6 and Convair CV-240, among others. More than 125,000 R-2800s were built between 1939 and 1960. U.S. National Archives The Astro-40 is an electric motor developed by AstroFlight, a company that specializes in electric-powered products, such as radio-controlled aircraft, unmanned aerial vehicles, motors and electric airplanes. The Astro-40 motor was the first solar-powered motor, and it powered the Sunrise II, the first solar-powered unmanned airplane, in 1974. The follow-on to the Astro-40, called the Cobalt 40, powered the single-seat Gossamer Penguin with a person on board in 1980. A 600-watt solar panel collected power for the Cobalt 40, which turned it into thrust via a three-stage transmission and an 11-foot propeller. The motor spun at 15,000 rpm, but the propeller turned at only 120 rpm. While the Astro-40 flew in very few airplanes, it will ultimately be seen as a pioneer for the coming electric-powered aircraft revolution. NASA In the early 1930s, Continental Motors developed the first engines in a lineup of products that the company would eventually expand to create a catalog of dozens of models powering tens of thousands of light airplanes around the world. These engines featured an unusual design by today’s standards: a four-cylinder, flat-head, side valve, single-ignition design with one head for two cylinders. The A40 is the best known of these types of engines today, as it powered the first production Piper Cub and led to the development of a line of engines, including the legendary C-65, L90 and O-200 models, that powered many tens of thousands of light aircraft over the next 80 years. Stahlkocher via Wikipedia The Allison V-1710 emerged from an Army project in the lead-up to World War II to develop a high-power, liquid-cooled engine. More than 70,000 were built between 1931 and 1948, as the V-12 powered several legendary fighters, including the Lockheed P-38 Lightning, Bell P-39 Airacobra, Curtiss P-40 Warhawk, North American P-51A Mustang, Bell P-63 Kingcobra and others. Allison started work on the V-1710 with a goal of producing a 1,000 hp engine, but development work remained slow until the late 1930s when the U.S. sought an engine for its dirigibles, which used German engines. The V-1710 turned out to be a sturdy and reliable engine for fighters at the outset of World War II and is best remembered for its turbo-supercharged version that gave the P-38 exceptional high-altitude performance. Courtesy of John Fowler Conceived in the 1940s, the Rolls-Royce/Olympus was the world’s first two-spool, axial flow turbojet engine, the most famous version of which powered the supersonic Concorde to legendary speeds. The engine was originally developed and produced by Bristol Aero Engines in England before Rolls-Royce bought the company. It powered the famed Avro Vulcan bomber and was selected for the BAC TSR-2, a proposed Cold War strike and reconnaissance aircraft that became the victim of ever-rising costs. The Rolls-Royce/Snecma Olympus 593 remains as the only afterburning jet engine ever to power a commercial airliner. Four Olympus 593 engines each producing 32,000 pounds of thrust enabled Concorde to cruise at Mach 2.2. No one knows your factory engine better than the factory that built it in the first place. Visit www.Lycoming.com to find your local distributor. This little four-cylinder engine from Pennsylvania manufacturer Lycoming epitomizes the light-airplane engine, helped by the fact that it powered some of the most popular light planes ever, including later models of the Cessna 172 and the Piper PA-28 Cherokee. With four cylinders arranged two per side, big air-cooled heads to keep the cylinders happy, a normally carbureted fuel system and dual magneto ignition, all driving a fixed-blade prop, the 150 hp O-320 took a 1930s design and updated it with the latest materials and manufacturing techniques. The bottom line is the O-320 delivers reliability, affordability and familiarity. Arguably one of the most noteworthy engines in aviation history was this low-powered, handmade model built by the Wright brothers’ ace mechanic Charlie Taylor. Using chain drives to spin the propellers, this primitive four-banger provided the 12 horsepower needed to just barely get the Wright Flyer airborne on Dec. 17, 1903. While the Wrights get the bulk of the glory for their pioneering experiments in flight, it could be argued that without Taylor, the Wright Flyer would have been just another little-known failed experiment in flight. A joint venture between GE and French company Snecma, the CFM56 was launched in the mid-1970s and has become one of the most produced jet engines thanks to its adoption by Boeing for a new single-aisle airliner called the 737, which would become the best-selling airliner. The CFM56 is a high-bypass ratio turbofan, which means that most of the air that goes into the engine bypasses the turbine section and instead powers the engine’s huge spinning fan. High-bypass design means higher fuel efficiency, lighter weight and much quieter performance — all hallmarks of modern jet aviation. The Merlin produces that most magical sound of airplanes in flight: the humming roar of 12 cylinders in perfect harmony doing their thing at an easy deep-throated gallop. Designed in the pressure cooker of wartime England, the Merlin powered dozens of airplanes, including iconic models such as the Supermarine Spitfire, Avro Lancaster and de Havilland Mosquito. A Packard-licensed version helped create the ultimate World War II fighter: the North American P-51D Mustang. The Merlin edge gave the Mustang fighter/escort the kind of range necessary to watch over B-17 bombers while they made their way deep into German-held territory, which quickly turned the tide of war. JAW via Wikipedia Over the past six decades, the Pratt & Whitney Canada PT6 engine has become the gold standard in the turboprop world. A turboprop engine works very much like a modern jet engine, but instead of driving exhaust gas or a jet fan, the turbine section drives a propeller. At higher altitudes than piston-powered airplanes fly but below jet levels, a turboprop relies on the most efficient type of propulsion, as a propeller remains very efficient at turning fuel into thrust in the thinner breathable altitudes through abound 30,000 feet. There are many turboprop engines by a number of different manufacturers, but none rivals the success of the PT6, which first flew in 1961. To date, Pratt & Whitney has built more than 40,000 of these engines for more than 100 different kinds of airplanes. Courtesy of Pratt & Whitney Keep the countdown going and check out Flying’s Top 100 Airplanes list of the most influential aircraft of all time. Click here to view the list. Or check out our Readers’ Choice: 50 Amazing Aircraft Engines gallery to vote in one more engine we might have missed!