The rotary engine is an early type of internal combustion engine, usually designed with an odd number of cylinders per line in a radial configuration, in which the crankshaft remains stationary in operation, with all the crankcase and cylinder inserted around it as a unit. The main application is flight, although it is also used before major flight roles, in some early motorcycles and cars.
This type of machine is widely used as an alternative to conventional inline engines (straight or V) during World War I and the years before the conflict. It has been described as "a highly efficient solution to power output problems, weight, and reliability".
In the early 1920s, the limitations inherent in this type of machine have made it obsolete.
Video Rotary engine
Deskripsi
Perbedaan antara mesin "putar" dan "radial"
A rotary engine is essentially a standard Otto cycle engine, with a cylinder arranged radially around a central crankshaft like a conventional radial engine, but instead of having a fixed cylinder block with a rotating crankshaft such as with a radial engine, the crankshaft remains stationary and overall cylinder block spins around it. In its most common form, the crankshaft remains firmly to the fuselage, and the blades just dart onto the front of the crankcase.
This difference also has many impacts on the design (lubrication, ignition, refueling, cooling, etc.) and works (see below).
The Musee de l'Air in Paris has exhibited a special "sectioned" work model of a machine with seven "radially discarded" cylinders. It alternates between "swivel" and "radial" modes to show the difference between the internal motion of the two machine types.
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Just like a "fixed" radial machine, rotary is generally built with an odd number of cylinders (usually 5, 7 or 9), so the constant firing order of each other piston can be maintained, to provide smoothness. Rotary machines with the same number of cylinders are mostly "two row" types.
Most rotary engines are arranged with cylinders that lead out of a single crankshaft, in the same general form as radials, but there are also rotary boxer engines and even one-cylinder rotaries.
Advantages and Disadvantages
Three key factors contributed to the success of the revolving engine at the time:
- Smooth motion: Rotary produces power very smoothly due to (relative to engine mounting point) no reciprocal parts, and the relatively large rotating mass of the crankcase/cylinder (as a unit) acts as a flywheel.
- Enhanced cooling: when the machine is running a rotating crankcase assembly creates its rapidly cooling air flow, even with the aircraft at rest.
- Strong excellence: many conventional engines must have a gravity wheel added to flatten the power impulse and reduce vibration. Rotary engines gain superior power-to-weight ratios with no need to add flywheels. They share with other radial configuration machines the advantage of small and flat crankcases, and because efficient air conditioning system cylinders can be made with thinner walls and shallower cooling fins, which further reduce the weight.
The engine designers are always aware of the limitations of rotary machines so that when static-style engines become more reliable and provide better weight and fuel consumption, the days of the turning machines are numbered.
- The rotary engine has a fundamentally inefficient total losses signaling system. To reach the entire engine, the lubricating medium is required to enter the crankcase through a hollow crankshaft; but the centrifugal force of the spinning crankcase directly opposes any recycle. The only practical solution is the lubricant is aspirated with a mixture of fuel/air, as in a two-stroke engine.
- The increase in power also comes with increasing mass and size, multiplying the gyroscopic precession of the rotating engine mass. This produces stability and control problems in the aircraft on which the machine is installed, especially for inexperienced pilots.
- The power output goes deeper into the air resistance of the rotating engine.
- Machine control is very complicated (see below), and results in fuel wastage.
The Bentley BR2 End of PDI, as the largest and strongest swivel engine, has reached the point where this type of machine can not be further developed, and it is the last of its kind to be adopted into the RAF service.
Maps Rotary engine
Playback engine control
Rotari Monosoupape
It is often asserted that a rotary engine does not have a throttle and therefore power can only be reduced by cutting the trigger periodically by using a "blip" switch. This is almost literally true of the "Monosoupape" type (single valve), which takes most of the air into the cylinder through the exhaust valve, which remains open for a portion of the piston downstroke. Thus the wealth of the mixture in the cylinder can not be controlled through the intake of the crankcase. The "throttle" (fuel valve) of the monosoupape only provides a very limited rate of regulation speed, because opening it makes the mix too rich, while closing it makes it too slim (either in the case of rapidly stalling the engine, or damaging the cylinder). The initial model displays a pioneering form of variable valve timing in an attempt to provide greater control, but this causes the valve to burn and is therefore abandoned.
The only way to run the Monosoupape machine smoothly on reduced rotation is with a switch that changes the normal combustion order so that each cylinder only fires once per two or three revolutions, but the engine remains more or less balanced. Like excessive use of the "blip" switch: running the engine in such settings takes too long to produce large amounts of unburned fuel and oil in the exhaust, and gather in the lower cowling, where it is a known fire hazard.
Rotari "Normal"
Most rotaries have a normal inlet valve, so the fuel (and lubricating oil) is fed into a cylinder that has been mixed with air - as in a normal four-stroke engine. Although conventional carburetors, with the ability to maintain a constant fuel/air ratio during the throttle opening range, are blocked by a rotating crankcase; it is possible to adjust the air supply via a separate flap valve or "bloctube". The pilot is required to set the throttle to the desired setting (usually fully open) and then adjust the fuel/air mix to adjust using a separate "fine adjustment" lever that controls the air supply valve (by means of manual choke control). Due to the large rotational inertia of the rotary engine, it is possible to adjust the fuel/air mixture appropriately with trial and error without stalling, although this varies between different types of machines, and in any case it takes a lot of practice to get the required talent. After starting the engine with known settings allowing for idle, the air valve is opened until the maximum engine speed is obtained.
Stopping the running engine again to reduce the rotation is possible by closing the fuel valve to the required position while adjusting the appropriate fuel/air mixture. The process is also complicated, thus reducing the speed, especially when landing, is often done by cutting the trigger using the blip switch intermittently.
Cutting a cylinder using a ignition switch has the disadvantage of letting the fuel continue through the engine, pumping spark plugs and making the smooth restart problematic. Also, a mixture of fuel oil can collect in the cowling. Since this can cause a serious fire when the switch is released, it becomes common practice for some or all of the bottom of the basically circular rake in most rotary engines to be cut, or equipped with drainage slots.
In 1918 a Clerget handbook suggested keeping all necessary controls by using fuel and air controls, and starting and stopping the engine by turning on and off the fuel. The suggested landing procedure involves turning off the fuel using the fuel lever, while allowing the blip to ignite. Wind-propellers keep the engine running without giving any power when the plane goes down. It is important to leave the ignition key on to allow the spark plug to continue and to keep it from oiling, so that the engine can (if all goes well) is restarted simply by reopening the fuel valve. The pilot is advised not to use the ignition button, as it will eventually damage the machine.
The pilot of a live or reproducing aircraft equipped with a rotary engine still finds that the blip switch is useful on landing, as it provides a more reliable and faster way to start power if needed, rather than the risk of sudden engine failure, or the failure of the engine windmill to restart at the worst possible moment.
History
Millet
FÃÆ' Â © lix Millet showed a 5-cylinder rotary engine made into bicycle wheels at the Exposition Universelle in Paris in 1889. Millet had patented the machine in 1888, so it should be considered a forerunner of the internal combustion engine. A machine powered by the engine participated in the Paris-Bordeaux-Paris race of 1895 and the system was put into production by Darracq and Company London in 1900.
Hargrave
Lawrence Hargrave first developed a revolving engine in 1889 using compressed air, intending to use it in a powerful flight. The weight of the material and the lack of quality machining prevent it from becoming an effective power unit.
Balzer
Stephen M. Balzer of New York, a watchmaker, made a revolving machine in the 1890s. He is interested in the layout of play for two main reasons:
- To produce 100 hp (75 kW) at low speed where the day machine is running, the pulses generated from each step of the combustion are quite large. To muffle this pulse, the engine needs a large flywheel, which adds weight. In rotary design, the engine acts as its own flywheel, so the rotary can be lighter than a conventional engine of the same size.
- The cylinder has a good coolant airflow over it, even when the aircraft is resting - which is important, because the aircraft's low speed at the time provides a limited cooling air flow, and the day's alloy is less advanced. Balzer's initial design was even distributed with cooling fins, although the next rotary did have this common feature of air-cooled engines.
Balzer produced a 3-cylinder rotating engine in 1894, then later involved in Langley's Aerodrome effort, which made him bankrupt when he tried to make a larger version of his machine. The Balzer rotary engine was then converted into a static radial operation by Langley's assistant, Charles M. Manly, creating the famous Manly-Balzer engine.
De Dion-Bouton
The famous De Dion-Bouton company produced the experimental 4-cylinder rotary engine in 1899. Although intended for flight use, it was not plugged into any aircraft.
Adams-Farwell
The Adams-Farwell company car, with its first company milling prototype using a 3-cylinder rotary engine designed by Fay Oliver Farwell in 1898, led to the production of Adams-Farwell cars with the first 3-cylinder engine, then very short after that 5 cylinders later in 1906 , as an early American car maker that used a rotary engine that was firmly manufactured for automotive use. Emil Berliner sponsors the development of the Adams-Farwell 5-cylinder rotary engine design concept as a lightweight unit for failed helicopter experiments. The Adams-Farwell engine then used a fixed-wing aircraft in the US after 1910. It has also confirmed that the GnÃÆ'Â'me design comes from Adams-Farwell, because the Adams-Farwell car is reported to have been shown to France. Army in 1904. Unlike the later Gnave engine, and like the rotation of the Clerget 9B and Bentley BR1 planes, Adams-Farwell rotary has a conventional valve inlet and a conventional inlet valve mounted on the cylinder head.
Gnome
The Gnome machine is the work of three brothers Seguin, Louis, Laurent and Augustin. They are talented engineers and grandson of famous French engineer Marc Seguin. In 1906, the eldest brother, Louis, had formed the SosiÃÆ' Â © des Moteurs Gnome to build stationary machines for industrial use, having the production licensed from a single cylinder stationary machine from the Motorenfabrik Oberursel - which, in turn, built licensed Gnome machines for German aircraft during World War I.
Louis joined his brother Laurent who designed a special rotary engine for aircraft use, using a cylinder Gnom machine. The first experimental engine of the brothers is said to have become a 5-cylinder model that develops 34Ã,® hp (25 kW), and is a radial engine rather than a rotary engine, but no photographs survive from a five-cylinder experimental model. The Seguin brothers then switched to a rotary engine for the benefit of better cooling, and the world's first rotating, 7-cylinder, 50-hp (37-kW) air-cooled (37-kW)) engine featured at the Paris car show 1908. The first Omega Gnome which was built still exists, and is now in the Smithsonian Museum of Air and Space collections. Seguins use the highest-strength materials available - newly developed nickel steel alloys - and retain their weight with solid metal machining components, using the best American and German machine tools to create engine components; the cylindrical wall of 50Ã, the Gnome hp is only 1.5 mm (0.059 inches) thick, while the connecting rod is milled with a deep central tube to reduce the weight. While slightly powered in terms of power units per liter, its power-to-weight ratio is an incredible 1 hp (0.75 kW) per kg.
The following year, 1909, the inventor, Roger Ravaud, attached one to his AÃÆ' Â © roscaphe , a combination of hydrofoil/airplane, which he entered in a motorboat and a flight contest in Monaco. Henry Farman using Gnome on a famous Rheims plane that year brought him to fame, when he won the Grand Prix for long-distance non-stop flying - 180 kilometers (110 miles) - and also set a world record for aviation durability. The first successful seaplane flight, owned by Henri Fabre Le Canard , was supported by Gnome Omega on March 28, 1910 near Marseille.
Gnome's rotary production increased rapidly, with about 4,000 produced before World War I, and the Gnome also produced a two-line version (100 h.p. Double Omega), a larger 80 hp Gnome Lambda and 160Ã, hp two Lambda Double lines. With other machine standards in those days, the Gnome was deemed less temperamental, and credited as the first machine to run for ten hours between reshuffles.
In 1913 the Seguin brothers introduced the new Monosoupape ("valve") series, which replaced the inlet valve on the piston by using a single valve on each cylinder head, which was duplicated as an inlet and exhaust valve. The engine speed is controlled by varying the opening time and the level of the exhaust valve using the lever acting on the valve tappet roll, the system which is then abandoned due to valve burning. The Monosoupape weight is slightly lower than the previous two valve engines, and uses less lubricating oil. Monosoupape 100Ã, hp is built with 9 cylinders, and develops rated power at 1,200rpm. Gnome 9N rotary engine with a 160 hp nine-cylinder engine then uses the Monosoupape valve design, and is the last revolving engine design known to use such a cylindrical head valve shape.
Rotary engines manufactured by Clerget and Le RhÃÆ'Â'ne firms use conventional valves operated with pushrod on the cylinder head, but use the same principle to draw fuel blends through crankshaft, with Le RhÃÆ'Â'nes having a leading copper feed tube running from the crankcase to the top of each cylinder to receive an intake charge.
The 80-hp (60-kW) seven-cylinder Gnome was standard at the outbreak of World War I, as Gnome Lambda, and quickly found itself used in a large number of aircraft designs. It was so good that it was licensed by a number of companies, including the German Motorenfabrik Oberursel company that designed the original Gnom engine. Oberursel was later purchased by Fokker, whose copy was 80Ã, hp Gnome Lambda known as Oberursel U.0. It was not at all unusual for the French Gnomes, as used in the early example of the Bristol Scout biplane, to fulfill the German version, ignited Fokker E.I Eindeckers, in battle, from the second half of 1915.
The only attempt to produce double-row rotary engines in any volume was done by Gnome, with their dual 160 hp Lambert fourteen-cylinder design, and with early World War I clones of German Oberursel from Double Lambda design, U.III of the power ratings same. While an example of Double Lambda proceeded to move one of the Deplussin Monocoque racing planes to a world record speed of nearly 204 km/h (126 mph) in September 1913, Oberursel U.III was only known to have been installed into several German military production planes, Fokker E.IV and the Fokker D.III fighter biplane, both of which failed to become a successful combat partially due to the poor quality of the German power plant, which tended to fade after only a few hours of combat flight.
World War I
The advantageous power-to-weight ratio of rotary is their greatest advantage. While larger, heavier aircraft rely almost exclusively on conventional in-line engines, many fighter designers choose rotation until the end of the war.
Rotary has a number of disadvantages, especially very high fuel consumption, in part because the engine usually runs at full speed, and also because the valve time is often less than ideal. Oil consumption is also very high. Due to the primitive carburation and absence of true sump, lubricating oil is added to the fuel/air mixture. This machine makes the smoke heavy with smoke from partially burned oil. Castor oil is the lubricant of choice, since its lubrication properties are unaffected by the presence of the fuel, and the tendency of the gum-formers is irrelevant in total lubrication system losses. Unfortunate side-effects are that World War I pilots inhale and swallow large amounts of oil during flight, which causes persistent diarrhea. The flying clothes worn by rotary engine pilots are routinely soaked with oil.
The rotating mass of the machine also makes it, in effect, a great gyroscope. During the flight the effect level is not very clear, but when turning the gyroscopic precession becomes real. Due to the direction of engine rotation, the left turn effort is required and occurs relatively slowly, combined with a tendency to rise to the top, while the right turn is almost instantaneous, with a tendency for the nose to drop. In some planes, this can be advantageous in situations like dogfights. The Sopwith Camel suffers in such a way that it takes left-hand steering for both left and right turns, and it can be very dangerous if the pilot applies full force at the top of the loop at low airspeed. Pilot Camel Trainees are warned to try their first hard right turn just at an altitude above 1,000 feet (300 m). The most famous German enemy in Camel, Fokker Dr.I triplane, also uses a swivel engine, usually the Oberursel Ur.II clone of the Le Rhone 9J 110Ã power plant, hp made in France.
Even before the First World War, efforts were made to overcome the inertia of the rotary engine. In early 1906 Charles Benjamin Redrup had shown the Royal Flying Corps at Hendon a 'Reactionless' machine in which the crankshaft was rotated in one direction and cylinder block in the opposite direction, each riding a propeller. A further development of this is a 1914 'Hart' engine without a reaction designed by Redrup in which there is only one propeller connected to the crankshaft, but rotates in opposite direction with the cylinder block, so most cancel negative effects. This proved too complicated for reliable operation and Redrup transformed the design into a static radial machine, which was then tested on Vickers F.B.12b and F.B.16 experiments, unfortunately unsuccessful.
As the war progresses, aircraft designers demand an ever-increasing amount of power. Inline engines are able to meet this demand by increasing their upper rev limit, which means more power. Improvements in valve timing, ignition systems, and lightweight materials allow for higher revs, and by the end of the average machine war has increased from 1,200 rpm to 2,000. Rotation can not do the same thing because the cylinder drags rotates through the air. For example, if the initial 1,200 rpm war model increased its revs to only 1,400, the drag on the cylinder increased 36%, because the air drag increased with the square of the velocity. At lower rpm, drag can be ignored, but when the rev number rises, the rotary puts more power to rotate the engine, with less remaining to provide a useful boost through the propeller.
Siemens-Halske bi-rotary designs
A smart attempt to save the design, in a similar way to the "no reaction" engine concept from Redrup, made by Siemens AG. Crankcase (with propellers still tied directly to the front) and cylinders rotate counter-clockwise at 900 rpm, as seen externally from the "nose on" viewpoint, while the crankshaft (which unlike other designs, never "emerges" from crankcase) and other internal parts rotate clockwise at the same speed, so the set is effectively running at 1800 rpm. This is achieved by the use of bevel gearing at the rear of the crankcase, producing the Siemens-Halske Sh.III eleven-cylinder, with less drag and less net torque. Used in some types of final wars, especially the Siemens-Schuckert D.IV fighter, a new low-speed engine run, coupled with large, rugged propellers that sometimes have four blades (such as SSW D.IV used) the type supported by it's incredible climbing rate, with some examples of the final production of Sh.IIIa powerplant even said to give as much as 240 hp.
A new rotary aircraft, Fokker's own D. VIII, is designed at least in part to provide some use for the Oberursel factory backlog of 110Ã machines, hp (82 kW) Url, which is also redundant, clones of Le RhÃÆ'Â'ne 9J swivel.
Due to the blockade of allied shipping, Germany is increasingly unable to obtain the castor oil needed to lubricate their rotary engine properly. Substitutes are never entirely satisfactory - causing an increase in running temperature and reduced engine life.
Postwar
By the time the war ended, the rotary engine had become obsolete, and disappeared from usage fairly quickly. The Royal Air Force may use longer rotary machines than most other operators. The postwar RAF warfare force, Sopwith Snipe, used the rotary Bentley BR2 as the strongest (on some 230Ã, hp (170Ã, kW) rotary engines) ever made by the Allies of World War I. The standard RAF training aircraft from the early postwar years , The 1914 Avro 504K, has a universal mounting to allow the use of some low-powered round types, where there is a large surplus supply. Similarly, the Swedish FVM fighter ÃÆ'â € "1 Tummelisa, equipped with a Le-Rhone-Thulin 90Ã, hp (67Ã, kW) rotary engine, presented until the mid-thirties.
Designers had to balance the cheapness of the surplus-war machine against their poor fuel efficiency and operating costs of their total lubrication loss system, and by the mid-1920s, the rotation had more or less completely evacuated even in British service, largely by radial new generations "air-conditioned" stationary like Armstrong Siddeley Jaguar and Bristol Jupiter.
Experiments with the concept of rotary engine continue to be done.
The first version of the Michel 1921 engine, an unusual opponent's piston cam machine, uses the principle of a rotary engine, in which the "cylinder block" is rotated. It was soon replaced with a version with the same cylinder and cam, but with stationary cylinder and cam track rotating instead of crankshaft. The last version leaves the cam altogether and uses three crankshafts.
In 1930 Soviet helicopter pioneers Boris N. Yuriev and Alexei M. Cheremukhin, both employed by the Tsentralniy Aerogidrodinamicheskiy Institute (TsAGI, Central Aerohydrodynamic Institute), built one of the first practical single-lift rotor engines. with their single TsAGI 1-EA rotor helicopter, powered by two rotary M-2 engines designed and built by the Soviets, itself an up-to-date copy of the Gnome Monosoupape rotation machine from World War I. TsAGI 1-EA establishes an unofficial height record from 605 meters (1,985 feet) with Cheremukhin driving it on August 14, 1932 on twin M-2 rotary engine power.
Use in car and motorcycle
Although rotary engines are mostly used in airplanes, some cars and motorcycles are built with rotary engines. Probably the first is the Millet motorcycle of 1892. The famous motorcycle, winning a lot of races, is Megola, which has a revolving engine inside the front wheels. Another motorcycle with rotary engine is Charles Redrup's 1912 Redrup Radial, which is a 303 cc three-cylinder rotary engine mounted on a number of motorcycles by Redrup.
In 1904, Barry's engine, also designed by Redrup, was built in Wales: a 2.5-cylinder 2-cylinder spinning machine mounted inside a motorcycle frame.
In the 1940s Cyril Pullin developed the Powerwheel, the wheels with a rotating cylinder engine, coupling and drum brake within the hub, but never entered production.
Cars with rotary engines were built by American companies Adams-Farwell, Bailey, Balzer and Intrepid, among others.
Other play engines
In addition to the cylinder configuration moving around the fixed crankshaft, several different engine designs are also called rotary engines . The most prominent pistonless rotary engine, the Wankel rotary engine has been used by NSU in Ro80 cars, by Mazda in various cars like the RX-series, and in some experimental flight applications.
In the late 1970s a concept engine called Bricklin-Turner Rotary Vee was tested. Rotary Vee is similar in configuration to an elbow steam engine. The piston pair is connected as a solid V-shaped member, with each end floating in a pair of rotating cylinder cylinders. The spinning cylinder cylinder pair is set with its axis at a wide V-angle. Pistons in each cylinder move parallel to each other, not radial direction, The design of this machine has not yet go into production. Rotary Vee is intended to power the Bricklin SV-1.
See also
- Gasoline engine
- Monosoupape machine
- Manly-Balzer Machine
- Repeat disk machine
- Quasiturbine
- Turbine
- Wankel play engine
Note
External links
- Paris Musee de l'Air a combination of "rotary" and "radial" machine-kinetic display functions
- Smithsonian NASM GnÃÆ'Â'me Omega No.1 page
- Smithsonian NASM page Le RhÃÆ'Â'ne 9J
- Gnome Rotary animation in action
- Rotary's rotary miniature rotary website website
- A rotary machine that works only on compressed air
- Charles Redrup engine suite
- 1909 Gnome Omega Engine Video - Run April 2009
- Rotary Vee Bricklin-Turner Machine
- Bi-rotary engine from Franky Devaere
Source of the article : Wikipedia
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