Introduction to Aerobatic Aircraft Essay Example

place at air meets during the next several years, stunt flying didn't really develop any further until 1913, when Adolphe Pegoud was hired by French aviator-designer Louis Bleriot to test and display the maneuverability of the Bleriot XI design. On Sept. 1, Pegoud made the first inverted flight, which had been considered impossible by many.

Three weeks later, he added several more tricks to his repertoire, including a vertical Figure S, tail slides, flick turns, and a full 360-degree loop. At the time, it was thought that Pegoud was the first pilot to loop the loop, but it transpired that a Russian Army lieutenant, Petr Nikolaevich Nesterov, had done it on Sept. 9 over Kiev. Nesterov was first arrested for placing Army property at risk, but was soon declared a hero and promoted to captain.

Pegoud went to England in late September to give a series of demonstrations over Brooklands Race Course and British pilots were soon performing loops and other stunts. One of them, B. C.Hucks, teamed with Gustave Hamel of France to give a stunt display at an airshow on March 13, 1914. Hucks performed eight consecutive loops and Hamel did something described as "a pirouette on the tip of a wing," most likely a stall turn. Back in France, Pierre Chanteloup had advanced the art even farther, performing side slips, inverted dives, outside loops, and a spectacular effect he called a "tourbillon dive" in which his plane spun around its axis during a headlong dive from which he pulled out at the last possible moment.

America's first stunt flyer was Lincoln Beachey, who began his aerial career flying balloons and dirigibles.In 1911, he

was hired by Glenn Curtiss in 1911 as an exhibition pilot. Beachey won headlines for himself and the Curtiss Model D Headless biplane when he flew into Niagara Falls Gorge, dove to within 20 feet of the water, passed under a suspension bridge, and brought the plane safely up and out of the gorge. Beachey often raced above a track against a car driven by Barney Oldfield, finishing the race with a series of loops. He was killed on March 14, 1915, when the wings came off his Beachey-Eaton Monoplane while he was performing stunts for a crowd of 50,000 people at the Panama-Pacific International Exposition in San Francisco.His death put a temporary halt to stunt flying in the United States.

World War I had begun in 1914 in Europe, where stunt pilots were using their skills to in aerial dogfights. Among them was Adolphe Pegoud. France's first fighter ace, who was shot down and killed in 1915. Even before the United States entered the war on April 6, 1917, American pilots were flying with the famed Lafayette Escadrille and other French units. Hundreds more were trained in 1917 and 1918.

When the war ended in November of 1918, many of the young flyers wanted to keep flying when they returned home.Fortunately for them, there were hundreds of thousands of people who wanted to watch airplanes. Air shows became enormously popular during the 1920s. Stunt flying, parachute jumping, and air races were staples of such shows. The stunts were often performed by professional test pilots hired by major aircraft companies who wanted to showcase their latest planes, but the U. S.

military was also involved. Jimmy

Doolittle of the U. S. Army Air Corps was famous as an aerobatic pilot and air racer long before he led the first bombing raid on Tokyo during World War II, and Al Williams was the top aerobatic performer and air racer for the U.S. Navy.

While stunt flying was a pastime in North America, it was transformed into the competitive sport of aerobatics in Europe. Mathematical methods of judging were developed independently in France and Germany about 1928. Both systems described specific maneuvers in detail and assigned each a degree of difficulty, as in competitive diving. The French Aero Club conducted the first world championship at Vincennes in Paris on June 9 and 10, 1934.

More than 150,000 spectators watched the nine competitors, who represented six countries: Czechoslovakia, France, Germany, Great Britain, Italy, and Portugal.Competitors performed an eight-minute compulsory program on the first day and a ten-minute free program on the second day. Two of the flyers were killed and a third survived a serious crash, but the remaining pilots insisted on going on with the competition. Gerhard Fieseler of Germany won the first prize of 100,000 francs. Women didn't compete in the world championship, but they had already had their own competition, the Coupe Feminine, also staged by the French Aero Club.

That event was won by Liesel Bach of Germany.Another major international competition was held in connection with the 1936 Olympic Games in Berlin. Again the winner was a German pilot, Otto von Hagenburg. Vera von Bissel, also of Germany and a student of Liesel Bach, won the women's event. Since World War II The tensions leading up to World War II

and the war itself ended international competition in aerobatics and in most other sports after the Olympics.

The Lockheed Trophy, established in 1955, began a revival of the sport, leading to the first modern World Aerobatic Championships, held in Bratislava, Czechoslovakia, in 1960.Supervised by the Federation Aeronautique Internationale (FAI), the world championships have been held biennially ever since, with two exceptions: the 1974 event was canceled because of the international fuel crisis and the 1992 championship was called off because of bad weather conditions shortly after it had begun. Since 2001, the world championship has been held in odd-numbered years. International competition, of course, required international agreement on a method of judging, which in turn required a system of describing aerobatic maneuvers.

A French pilot, Francois d'Huc Dressler, had published the beginnings of a notation system in 1955, but he died in 1957 before it was complete. Nevertheless, Dressler's system was used in 1960. The following year, Colonel Jose Luis de Aresti Aguirre of Spain published his own system and the Spanish Aero Club recommended that it be adopted internationally. The Dressler system was used again at the 1962 World Championships, but in 1963 the FAI decided to switch to the Aresti system for the 1964 event, which was hosted by Spain.The system uses symbols to describe about 15,000 aerobatic maneuvers and assigns a degree of difficulty to each. Also at the 1964 world championship, an "unknown compulsory" program was added to the competition.

Each team selected one maneuver for the program, and the judges then combined them into a sequence, adding figures where necessary. The sequence had to be flown without practice. The unknown compulsory

sequence remains a stable of major aerobatics events, along with the known compulsory and the free program. Since 1964, the world champion has been awarded the Aresti Cup.A separate women's championship was established in 1966. The winner receives the The Royal Aero Club Trophy.

The world championship stimulated growing U. S. interest in aerobatics. In 1965, the Experimental Aircraft Association (EAA), based in Oshkosh, Wisconsin, established a Precision Flying Division to develop national rules for the sport. The division was replaced by the Aerobatic Club of America in 1968. Internal squabbles led to the formation of the U.

S. -based International Aerobatic Club (IAC) in 1970. The IAC held the first true national championships that year in Fond du Lac, Wisconsin.The struggle between the two organizations ended in 1981, when the National Aeronautics Administration selected the IAC as the official national governing body for aerobatics. Charlie Hillard became the first U.

S. pilot to win the world title in 1972. The world championships came to the U. S. for the first time in 1980, when they were held at Oshkosh, home of the EAA.

The 1988 championships took place in Red Deer, Alberta, Canada, the 1996 event was held in Oklahoma City, and the 2003 championships were in Lakeland, Florida. National championships have been conducted annually since 1970.Types of aerobatic aircraft In the early days of flying, some pilots used their aircraft as part of a flying circus to entertain. Maneuvers were flown for artistic reasons or to draw gasps from onlookers. In due course some of these maneuvers were found to allow aircraft to gain tactical advantage during aerial combat or dogfights between fighter aircraft.

Aerobatic aircraft fall into two categories

— specialist aerobatic, and aerobatic capable. Specialist designs such as the Pitts Special, the Extra 200 and 300, and the Sukhoi Su-29 aim for ultimate aerobatic performance.This comes at the expense of general purpose use such as touring, or ease of non aerobatic handling such as landing. At a more basic level, aerobatic capable aircraft, such as the Cessna 152 Aerobat model, can be dual purpose—equipped to carrying passengers and luggage, as well as being capable of basic aerobatic figures. Fighters and civilians aircrafts both can perform aerobatics only if they are designed for aerobatic maneuvers, jet engine powered aircrafts have the tendency to go faster than turboprop engine powered aircrafts because of the shock wave effect on the propellers at the speed of sound barrier penetration.

Aerobatics differ depends on the mission, if it’s made for aerobatic competitions then a turboprop is ideal for that as long as no excessive speed is required and turboprop perform better at low speeds where the gyroscopic forces that a propeller driven aircraft can exploit. The turbojet engine is more practical for fighters as supersonic speed is required (in case of escape situation). in a jet powered aircraft are limited in scope as they cannot take advantage of the gyroscopic forces. Different types of maneuvering and super maneuveringAerobatics is the practice of flying maneuvers involving aircraft attitudes that are not used in normal flight.

Aerobatics are performed in airplanes and glidersfor training, recreation, entertainment and sport. Some helicopters, such as the MBB Bo 105, are capable of limited aerobatic maneuvers. Most aerobatic maneuvers involve rotation of the aircraft about its longitudinal (roll) axis or lateral (pitch) axis. Other maneuvers, such as a spin, displace the aircraft about its vertical (yaw) axis. Maneuvers are often combined to form a complete aerobatic sequence for entertainment or competition.Aerobatic

flying requires a broader set of piloting skills and exposes the aircraft to greater structural stress than for normal flight.

In some countries, the pilot must wear a parachute when performing aerobatics. Aerobatics consist of five basic maneuvers: Lines (both horizontal and vertical), Loops, Rolls, Spins, and Hammerheads. Most aerobatic figures are composites of these basic maneuvers with rolls superimposed. AEROBATIC FIGURES ROLLS There are four basic types of rolls: Aileron Roll  -  Barrel Roll  -  Slow Roll  -  Snap Roll Aileron RollsAileron rolls are flown with the rudder and elevator in the neutral position during the roll.The aileron is fully deflected in the direction of the roll.

This is the easiest of the rolls to fly. The aileron roll is started by pulling the nose up to 20 - 30 degrees above the horizon. The elevator is then neutralized and the aileron fully deflected in the direction of the roll. The controls are maintained in that position till the roll is completed. After the roll is completed the nose is usually 20 - 30 degrees below the horizon. | Barrel roll The Barrel roll is a combination between a loop and a roll.

You complete one loop while completing one roll at the same time.The flight path during a barrel roll has the shape of a horizontal cork screw. Imagine a big barrel, with the airplanes wheels rolling along the inside of the barrel in a cork screw path. During a barrel roll, the pilot always experiences positive Gs. The maximum is about 2.

5 to 3 G. The minimum about 0. 5 G. Slow rolls Slow rolls have to be flown normally on

a straight line (exception is the avalanche).

The roll rate has to be constant and the longitudinal axis of the plane has to go straight. This requires constantly changing rudder and elevator control inputs throughout the roll.Hesitation or point rolls include stops at certain roll angles. The number on the base of the roll symbol describes the number of points the roll would have if it were a 360°  roll. Allowed are 2 point, 4 point and 8 point rolls. The fraction on the arrow of the roll symbol describes what fraction of a full roll is to be executed.

If no points are specified, rolling is done without hesitations. If no fraction is specified, a roll symbol that starts at the line specifies a half roll (see description of the Immelman). A roll symbol that crosses the line specifies a full roll (first figure).The second figure shows the symbol for 2 points of a 4 point roll (adding up to half a roll) from upright to inverted flight. Snap rolls Snap rolls also have to be flown normally on a straight line. A snap roll is similar to a horizontal spin.

It is an autorotation with one wing stalled. Figure 1 shows the symbol for a regular snap roll. Figure 4 for an outside snap. In the regular snap, the plane has to be stalled by applying positive G forces. In an outside snap, the plane is stalled by applying negative G. In both cases rudder is then used to start autorotation just like in a spin.

LOOPSAvalanche - square loop - eight-sided loop – Immelman – split s – English bunt – half

Cuban eight – Cuban eight – reversed half Cuban eight – reversed Cuban eight – inside outside eight. Loop This is one of the most basic manoeuvres, but not easy to fly well. It has to be perfectly round entry and exit having to be at the same altitude. The difficulty in flying this maneuver well is in correcting for effects of wind drift. The maneuver starts with a pull-up of about 3 - 4 G.

Once past the vertical, the back pressure on the elevator is slowly relaxed to float over to top of the loop to keep it round.Past the top, the back pressure is slowly increased again throughout the back part till horizontal flight. The plane has to stay in one plane with the wings orthogonal to the flight path. Rudder is used to maintain the plane of the figure and ailerons are used to maintain the orientation of the wings Avalanche This is the basic loop with a roll (usually a snap roll) at the top of the loop.

The roll has to be centered at the top of the loop. Square Loop This is a variation of the basic loop. The two vertical lines and the horizontal line on top have to be of the same length.The exit line at the bottom has to be at least as long as the other three sides. The quarter loops that connect the four sides have to have the same radius at each corner.

Eight-Sided Loop This is another variation of the basic loop. The two vertical lines, the 45° lines and the horizontal line on top all have to be of the

same length. The exit line at the bottom has to be at least as long as the other seven sides. The eight loops that connect the eight sides have to have the same radius at each corner Immelman The figure starts with a half loop to inverted flight. A half roll then results in horizontal upright flight.This is one of the manoeuvres that have been used in WW I to reverse direction.

This maneuver does not preserve speed and altitude. It trades speed for altitude. The figure starts with a half roll to inverted followed by the second half of a loop downward. Split-S This is another maneuver to reverse direction.

This one, like the Immelman, does not preserve speed and altitude. In this case it trades altitude for speed English Bunt This figure also is the second half of a loop downward, this time an outside loop.You push forward and fly the second half of an outside loop till you are in horizontal inverted flight. Make sure you are not too fast going into the maneuver, otherwise you may exceed redline speed. Half Cuban Eight Five-eighths of a loop to a down-line at a 45° angle. The plane is inverted at this point.

Centered on this down line is a half roll from inverted to upright. A pullout to horizontal completes the figure. This is another one of the manoeuvres that reverse direction. The down line can be used to adjust the altitude and speed at the end of the figure. Reverse Cuban EightTwo Half Cuban Eights can be combined to form a Cuban Eight or Lay-down Eight. In this figure in competition the

two looping parts have to be flown at the same altitude with the same radius.

The exit has to be at the same altitude as the entrance to the figure. Reverse Half Cuban Eight This figure starts with a pull to a 45° up-line. Centered on this line is a half roll from upright to inverted. Five-eighths of a loop complete the figure to horizontal flight. This again is one of the manoeuvres that have been used to reverse direction while preserving altitude and airspeed.Reverse Cuban Eight Like the Cuban Eight, a Reverse Cuban Eight can be formed by flying two Reverse Half Cuban Eights back to back Inside-Outside Eight This figure is similar to a Full Cuban Eight, but it does not contain any rolls.

The second loop is an outside loop. Again, the two loops have to have the same radius and have to be flown at the same altitude. Entry and exit have to be at the same altitude Hammerhead It starts with a quarter loop into a vertical climb. When the plane stops climbing, it pivots around its vertical axis (which is now horizontal).The nose moves in a vertical circle from pointing up through the horizon to pointing down.

After moving vertically down to pick up speed again, the maneuver is finished with the last quarter of a loop to horizontal flight. This figure can have optionally rolls on both the up-line and the down-line. The quarter loop is flown just like the first part of a loop. When the plane is vertical, the elevator backpressure is released completely. During the vertical line up, some right aileron and right rudder is

needed to maintain the vertical attitude because of the engine torque and p-factor.

When the plane has slowed enough, full rudder initiates the turnaround. It is followed by right-forward stick (right aileron and forward elevator) to keep the plane from torquing off. The pivot is stopped with opposite rudder when the nose points straight down. When the pivot is completed, the ailerons and rudder are neutralized.

Elevator and rudder are used to keep the nose pointing straight down. The pivot must be completed within one wingspan. Rolls on the down line require only aileron input if the plane is trimmed correctly. Humpty-Bumb This maneuver is sometimes called a hammerhead stall.This is not an accurate name because the airplane never stalls. The airspeed may be very low, close to zero, but since there is no wing loading during the turn-around, there is no stall (at zero g wing loading, a wing does not stall).

The plane is flying throughout the maneuver with all the control surfaces effective (although sometimes only marginally so). This also is one of the manoeuvres that have been used to reverse direction while adjusting altitude and airspeed by changing the length of the down-line. The figure starts with a quarter loop to a vertical climb.A half loop then results in a vertical down-line. The figure completes with another quarter loop to horizontal flight.

The looping part on the top of the figure does not have to be the same radius as the two other looping portions (the quarter loops going into and coming out of the humpty). Again the figure can have optionally rolls on both the up-line and the down-line. Competition Turn

Competition turns are not the coordinated manoeuvres that you use in normal flying. In a competition turn you first roll to the desired bank. It has to be at least 60°. Once the bank is established the turn is started.

The plane has to maintain a constant bank and altitude throughout the turn. At the end of the turn, the turn is stopped and then the wings leveled for horizontal flight. The example shows the symbol for a 270° turn. Rolling Turn This maneuver combines a turn with rolls. The example shows a 360° turn with four rolls to the inside.

The plane has to maintain a constant roll rate, constant turn rate and constant altitude throughout the rolling turn. This maneuver is quite difficult to fly. It requires constantly changing inputs from all three controls (rudder, aileron, elevator) TailslidesThese manoeuvres involve bringing the airplane to a complete stop in a vertical attitude and then sliding back a visible amount. The airplane must then tip over and fall through a vertical down position.

Figure 1 indicates a tail slide with the wheels down during the flip. Figure 2 is a tailslide with the wheels up (inverted) during the flip. Going into the figure and coming out, the same rules apply as for other figures (quarter loops of constant and equal radius, vertical lines). Spin Spins come in 3/4, 1, 1 1/4 and 1 1/2 turns. During spin entry, the plane has to show a stall break, followed by the auto-rotation.

The rotation has to stop exactly after the specified number of turns. Once the rotation has stopped, a vertical downline has to be established. In a crossover

spin, the plane is first stalled upright. At the stall break, the nose is pushed forward to get into an inverted spin while maintaining the stall. The inverted spin is then completed as it would be for an inverted spin with entry from inverted flight.

chandelle The Chandelle is not used in aerobatic competition. On the FAA power commercial pilots test a Chandelle is defined as a maximum performance climbing turn through 180 degrees while maintaining a constant turn rate.The idea is that this is a "plan ahead" manoeuvre. You first establish a medium bank depending on the performance of your aircraft.

Then a smooth pull-up is started. The angle of bank stays constant during the first 90 degrees of turn, while the pitch angle increases steadily. At the 90 degree point the plane has the maximum pitch angle which should be close to the critical angle of attack. During the second 90 degrees of turn, the pitch angle is held constant, while the bank angle is smoothly decreased to reach 0 degrees of bank at 180 degrees of turn with the airspeed close to the stall speed.The plane should not settle during the last part of the manoeuvre and the recovery.

The decreasing bank angle during the second half of the Chandelle will maintain a constant turn rate together with the decreasing airspeed. The turn needs to be kept coordinated by applying the right amount of rudder. A Chandelle to the left is quite different than one to the right because of the ever increasing amount of p-factor in the second half of the manoeuvre. Wing-Over The Wing-Over is a competition manoeuvre in glider

aerobatics. You pull up and at the same time bank the plane.

When the bank increases past 45°, the nose will start to drop while the bank keeps increasing and the plane keeps turning. Halfway through the manoeuvre, the plane has turned 90°, the fuselage is level with the horizon and the bank is 90°. The plane is above the original flight path. The nose then keeps dropping below the horizon and the plane keeps turning, while the bank is shallowed. When the bank drops below 45°, the nose is pulled up towards the horizon and the plane reaches horizontal flight with wings level after 180° of turn.At the completion of the manoeuvre, the plane is at the same altitude as on entry and flying in the opposite direction.

Lazy Eight Like the Chandelle, the Lazy Eight is not a competition manoeuvre but is required for the power commercial pilot test. The aerobatics version of the Lazy Eight is two wingovers back to back. The FAA commercial pilot version is similar but the maximum bank is only 45 degrees instead of 90 degrees. The name Lazy Eight comes from the fact that the nose of the airplane is following a figure 8 on its side on the horizon. Basic fighter maneuvers (BFM)Basic fighter maneuvers (BFM) are tactical movements performed by fighter aircraft during air combat maneuvering (ACM).

BFM principles BFM are generally grouped into two categories: * Primary BFM * Relative BFM Primary maneuvers are those which are performed without respect to an enemy's position. These are often simple maneuvers, such as climbs, turns and rolls. Relative maneuvers are performed in relation to the motion of another aircraft. These are often

more complex, including energy saving maneuvers, such as the high and low Yo-Yos, and repositioning maneuvers such as displacement rolls.It is easy to fall into the trap of considering BFM to be a series of set maneuvers providing a foolproof recipe for a dominant position.

The reality is that BFM are a series of fluid and often improvised proactive and reactive actions, varying infinitely according to range, altitude, speed, aircraft type, weapons system type and any of an enormous range of other factors. An extremely successful tactic one day may yield unfortunate results if repeated the next day, and pilots often credit luck as a major factor.BFM are normally considered to be individual maneuvers, where ACM is applied to the tactics behind dogfighting as a whole. In military training, BFM are often conducted against an adversary in the same type of aircraft.

This allows the pilot to fly against a machine with known performance values and allows aircrew to build their awareness of important concepts such as sight picture, rates of closure and line of sight rates that are cues to being successful in the visual arena. Dissimilar BFM are maneuvers performed by aircraft of two separate types (such as F-16 vs F/A-18).This training is valuable in that both pilots are not as aware of the performance capabilities and characteristics of the other aircraft and, therefore, must rely on the fundamental BFM principles and evaluation/decision making skills to maneuver to an advantageous position versus their opponent. This type of training, while less common, is the most beneficial for aircrew once basic BFM skills are mastered. Energy management In combat a pilot is faced with a variety of

limiting factors.

Some limitations are constant, such as gravity, drag, and thrust-to-weight ratio.Other limitations vary with speed and altitude, such as turn radius, turn rate, and the specific energy of the aircraft. The fighter pilot uses BFM to turn these limitations into tactical advantages. A faster, heavier aircraft may not be able to evade a more maneuverable aircraft in a turning battle, but can often choose to break off the fight and escape by diving or using its thrust to provide a speed advantage.

A lighter, more maneuverable aircraft cannot usually choose to escape, but must use its smaller turning radius at higher speeds to evade the attacker's guns, and to try and circle around behind the attacker.BFM are a constant series of trade-offs between these limitations to conserve the specific energy state of the aircraft. Even if there is no great difference between the energy states of combating aircraft, there will be as soon as the attacker accelerates to catch up with the defender. Instead of applying thrust, a pilot may use gravity to provide a sudden increase in kinetic energy (speed), by diving, at a cost in the potential energy that was stored in the form of altitude. Similarly, by climbing the pilot can use gravity to provide a decrease in speed, conserving the aircraft's kinetic energy by changing it into altitude.

This can help an attacker to prevent an overshoot, while keeping the energy available in case one does occur. Turn performance Both turn rate, (degrees per second), and turn radius, (diameter of the turn), increase with speed, until the "corner speed" is reached. At this point, the growing turn radius begins to decrease the turn rate, so the aircraft will reach its best

turn performance at its particular corner speed. The corner speed of an aircraft is the minimum speed at which it can sustain the maximum g-force load, and varies with its structural design, weight, and thrust capabilities.It often falls in the area of 250 to 400 knots.

Instantaneous turn rate describes maximum g turns which cause a loss in energy, either in the form of speed or altitude. This loss may be compensated for, to a degree, by increasing thrust, known as "excess specific power. " This usually occurs during hard turns or even harder breaks. Only by turning the aircraft at its best "sustained turn rate" can the aircraft maintain its specific energy.

However, situations in combat may require a change in energy, and energy may also be increased by pulling less than the maximum sustained g-force. Pursuit curves.Successful BFM requires geometry as much as it does skill and stamina. Pilots must know their aircraft's corner speed, as well as optimum angles of bank(AOB) and angles of attack (AOA), without consciously thinking about them. At the same time, pilots must remain conscious of the angle between the opponent'svelocity vector and their own, called the angle off tail (AOT).

A high AOT causes a high rate of closure, but makes achieving a suitable guns solution nearly impossible. Acquiring a low AOT, (getting on the enemies tail), can decrease or even reverse closure rate, and is usually the primary goal before an overshootoccurs.However, an uncooperative defender may try to take advantage of the high closure rate by turning to increase AOT, forcing an overshoot. The AOT is often estimated by the position of the attacking aircraft's nose in relation to the defender. AOT are generally grouped into

three categories, called "pursuit curves.

" "Lead pursuit" occurs when the nose of the attacker points ahead of the defender, while "pure pursuit" happens when the attacker's nose points directly at the defender. If the attacker's nose points behind the defender the condition is known as "lag pursuit. Lead pursuit The primary purpose for lead pursuit is to provide closure, even when chasing a faster opponent. The high AOT presented during lead pursuit allows the attacker to quickly decrease the separation between aircraft simply by traveling a shorter path. However, lead pursuit causes the AOT to increase at a rapid rate. This causes the closure rate to increase as well, and, in an attempt to prevent an overshoot, the attacker will have to pull an increasingly tighter turn upon nearing the defender.

An attacker in lead pursuit is well within the defender's rear view.Unless the defender has enough of a speed advantage to escape by relaxing the turn and dropping into a shallow dive, the defender will likely turn sharply in an effort to increase the AOT, forcing the attacker to turn even harder, to overshoot, or to perform a maneuver out of the horizontal plane to compensate. Lead pursuit is used during gun attacks, because the fast motion of combat requires that the aircraft's cannons be aimed at a point in space ahead of the defender, where the enemy will be when the bullets arrive. This is called "leading the target. Lead pursuit presents the attacker with difficulty in maintaining sight of the opponent, as the nose of the attacking aircraft becomes an obstruction to the pilot's view. Pure pursuit Like lead pursuit, pure

pursuit is used to provide closure.

However, closure is not as rapid, nor is the rate of increase in AOT. This is not as effective against a faster moving opponent, so the attacker may need to accelerate to maintain pure pursuit. Pure pursuit is used when acquiring a missile lock. It both places the attacker further aft of the defender and presents the defender with the smallest amount of surface area to see.This complicates evasive action, since only the front of the attacking aircraft is in view. Lag pursuit Lag pursuit is used to stop or reverse closure rate and to decrease AOT, while allowing the attacker to maintain or increase forward separation.

Following outside the defender's turn radius, the attacker can maintain or increase energy while forcing the defender to turn at an energy depleting rate. "Hot side" lag occurs when there is a large amount of forward separation between aircraft, showing the top side of the defending fighter. This puts the attacker in the defender's rear view, and the common defense is to tighten the turn. Cold side" lag occurs when there is little separation, leaving the belly of the defending fighter in view. This puts the attacker in the defender's blind spot, and the common defense is to reverse the turn.

Unless the defender is markedly more maneuverable, and lateral separation is just right, lag pursuit cannot be maintained for long, causing the AOT to decrease until a suitable firing solution is presented. Out-of-plane maneuvers Maneuvering planes, showing oblique and vertical turns Maneuvers are rarely performed in the strictly vertical or horizontal planes.Most turns contain some degree of "pitch" or "slice. "

During a turn in an oblique plane, a pitch turn occurs when the aircraft's nose points above the horizon, causing an increase in altitude. A slice turn happens when the nose points below the horizon, causing a decrease in altitude. The purpose is not only to make the aircraft harder for an enemy to track, but also to increase or decrease speed while maintaining energy.

An out-of-plane maneuver enhances this effect, by diverting the fighter into a new plane of travel.Increasing the pitch or slice can quickly provide a change in speed, which can just as quickly be reversed by returning to the original plane of travel. Out-of-plane maneuvers are not only used to provide a reduction in turn radius, but also causes the fighter to fly a longer path in relation to the direction of travel. A maneuver such as a high Yo-Yo is used to slow closure and to bring the fighter into lag pursuit, while a low Yo-Yo is used to increase closure and to bring the fighter into lead pursuit.

During an out-of-plane maneuver, the attacker's nose no longer points at the defender.Instead, the aircraft is rolled until its lift vector, (an imaginary line running vertically from the center of the aircraft, perpendicular to its wings), is aligned ahead of, directly at, or behind the defender, using roll rate instead of turn rate to set the proper pursuit curve. The aircraft's velocity vector, (an imaginary line in the direction of motion) will be pulled in the direction of the lift vector. Displacement rolls A useful type of out-of-plane maneuver employed to decrease AOT are various barrel rolls called displacement rolls, in order to

shift the aircraft laterally from its projected flight path onto a new flight path.By controlling the roll rate the pilot can control the degree of displacement. An attacker following a more maneuverable opponent may become stuck in lag pursuit, (outside the defender's turn radius), unable to achieve a firing solution.

By displacing the turn, the two aircraft's flight paths will eventually cross. The AOT will then decrease until the nose of the attacker's aircraft points momentarily at the defender, and then ahead of the defender. A displacement roll is a good tactic whenever a reduction in turn radius is needed, but a decrease in turn rate is allowed. PositioningThere are three basic situations in air combat maneuvering requiring BFM to convert to a favorable result, which are neutral, offensive, and defensive.

Most relative maneuvers can be grouped into one of these three categories. Neutral Neutral positions generally occur when both opponents spot each other at the same time. Neither the pilot nor the opponents have the advantage of surprise. Neither has the ability to point the nose of their aircraft at the opponent with sufficient range to employ forward firing ordnance (missiles/guns) prior to the opponent presenting a threat of a similar manner.Each is focused on converting to an offensive situation while forcing their opponent into a defensive.

Offensive An offensive position generally occurs when the pilot gets sight of the opponent first. With the advantage of surprise, the pilot can maneuver into a better position to attack the opponent, making it more difficult for the enemy to evade the attack. Common tactics include increasing altitude and attempting to place the fighter directly between the sun and

the opponent. This helps put the pilot in a dominant position, primarily concerned with prosecuting their advantage for a kill.

An offensive position is generally defined as the ability to get above or behind the enemy. The pilot is able to create an energy advantage, providing the ability to swoop down on the opponent and spray the area with bullets while using the speed to climb back to a safe altitude. The attacker also has an orientation-related advantage, being able to press the attack while avoiding the enemy's weapons. Defensive A defensive position usually occurs when the pilot spots the attacker late.

Usually below or ahead of the opponent, the pilot is in a weak position, primarily concerned with denying a shot to the opponent and converting to a neutral position. The secondary goal is either to escape or to achieve a dominant position. If the attacker is at an energy disadvantage, the defender will likely use the speed to disengage, but, if the attacker is moving much faster, the defender will usually maneuver in order to force a dangerous overshoot. A dangerous overshoot happens when an attacker flies out in front of the defender, causing their roles to be reversed.Maneuvers of fighters Example of maneuvers * Basic: * Combat spread * Pitchback * Bell Tailslide * Split S * Immelmann turn * Thach Weave * Scissors * Chandelle * Complex: * High Yo-Yo * Low Yo-Yo * Lag Displacement Roll (High-G Barrel Roll) * Pugachev's Cobra * Pugachev's Turn a. k.

a. Cobra Turn * Kulbit * Herbst maneuver Combat spread The combat spread is the most basic of maneuvers used prior to engagement. A pair of

attacking aircraft will separate, often by a distance of one mile horizontal by 1500 feet vertical.The fighter with the lower altitude becomes the defender, while the wingman flies above in "the perch" position.

The defender will then attempt to lure their opponents into a good position to be attacked by the wingman. Defensive split A pair of fighters encountering one or two attackers will often use a defensive split. The maneuver consists of both defenders making turns in opposite directions, forcing the attackers to follow only one aircraft. This allows the other defender to circle around, and maneuver behind the attackers. BreakSpotting an attacker approaching from behind, the defender will usually break.

The maneuver consists of turning sharply across the attacker's flight path, to increase AOT. The defender exposes the aircraft to the attacker's guns for only a brief instant. The maneuver works well because the slower moving defender has a much smaller turn radius, and an aircraft moving in such a direction is very difficult to shoot. This can also help to force the attacker to overshoot, which may not be true had the turn been made away from the attacker's flight path.

Barrel roll attack The counter to a break is often a displacement roll called a barrel roll attack. A barrel roll consists of performing a roll and a loop, completing both at the same time. The result is a helical roll around a straight flight path. The barrel roll attack uses a much tighter loop than the roll, completing a full loop while only executing 3/4 of a roll.

The result is a virtual 90 degree turn, using all three dimensions, in the direction opposite

of the roll.Rolling away from the defender's break, the attacker completes the roll with the aircraft's nose pointed in the direction of the defender's travel. High-side guns pass If the attacker has a significant altitude advantage, a high-side guns pass is usually prudent. Sometimes called a "swoop," plus a variety of other names, it consists of a powered dive toward the rear quarter of a lower flying opponent.

Shooting with the cannons in a single, high-speed pass, the attacker uses excess kinetic energy to disengage from the fight in a zoom climb back to a safe altitude, restoring the potential energy.This allows the attacker to set up another attack and dive again. Surprise is often a key element in this type of attack, and the attackers will often hide in the sun or clouds, stalking their opponents until a good opportunity is presented. A high-side guns pass is a very effective tactic against a more maneuverable opponent, where the turning battle of a dogfight is best avoided. Immelmann An Immelmann trades airspeed for altitude during a 180 degree change in direction. The aircraft performs the first half of a loop, and when completely inverted, rolls to the upright position.

The Immelmann is a good offensive maneuver, for setting up a high-side guns pass against a lower altitude, slow moving opponent, going in an opposite direction. However, an Immelmann is a poor defensive maneuver, turning the defender into a slow moving target. Split-s The opposite of an Immelmann is the split-s. This maneuver consists of rolling inverted and pulling back on the stick, diving the aircraft into a half loop, which changes the aircraft's direction 180 degrees. The split-s is rarely a

viable option in combat as it depletes kinetic energy in a turn and potential energy in a dive.

It is most often used to set up a high-side guns pass against a lower but fast moving opponent that is traveling in the opposite direction. Also, the split-s is sometimes used as a disengagement tactic. Pitchback A pitchback is an Immelmann that is executed in some plane other than the vertical. Basically just a pitch turn, the fighter will be at some angle of bank before performing the half loop and roll. Unlike the Immelmann, a pitchback depletes less kinetic energy and is harder for an adversary to track.Low Yo-Yo The low Yo-Yo is one of the most useful maneuvers, which sacrifices altitude for an instantaneous increase in speed.

This maneuver is accomplished by rolling with the nose low into the turn, and dropping into a steeper slice turn. By utilizing some energy that was stored in the vertical plane, the attacker can quickly decrease range and improve the angle of the attack, literally cutting the corner on the opponent's turn. The pilot then pulls back on the stick, climbing back to the defender's height.This helps slow the aircraft and prevents an overshoot, while placing the energy back into altitude. A defender spotting this maneuver may try to take advantage of the increase in AOT by tightening the turn in order to force an overshoot.

The low Yo-Yo is often followed by a high Yo-Yo, to help prevent an overshoot, or several small low Yo-Yos can be used instead of one large maneuver. High Yo-Yo The high Yo-Yo is a very effective maneuver, and very difficult to

counter. The maneuver is used to slow the approach of a fast moving attacker while conserving the airspeed energy.The maneuver is performed by reducing the angle at which the aircraft is banking during a turn, and pulling back on the stick, bringing the fighter up into a new plane of travel.

The attacker then rolls into a steeper pitch turn, climbing above the defender. The trade off between airspeed and altitude provides the fighter with a burst of increased maneuverability. This allows the attacker to make a smaller turn, correcting an overshoot, and to pull in behind the defender. Then, by returning to the defenders plane, the attacker restores the lost speed while maintaing energy.Lag displacement roll A lag displacement roll, also called a "high-g barrel roll", is a maneuver used to reduce the angle off tail by bringing the attacker from lead pursuit to pure, or even lag pursuit. The maneuver is performed by rolling up and away from the turn, then, when the aircraft's lift vector is aligned with the defender, pulling back on the stick, bringing the fighter back into the turn.

This maneuver helps prevent an overshoot caused by the high AOT of lead pursuit, and can also be used to increase the distance between aircraft. High Yo-Yo defenseAn attacker in lead pursuit may need to correct with an out-of-plane maneuver. If the AOT is excessively high, the attacker will probably use a displacement roll. However, if the AOT is low enough, the attacker will likely use a high Yo-Yo. The high Yo-Yo defense can be a good tactic in these situations. The maneuver is performed when the attacker rolls away from the

turn to begin the correction.

The defender will begin to relax the turn by easing off of the stick, called "unloading," which causes both turn radius and speed to increase, restoring the fighter's lost energy.If the defender maintains the same angle of bank, the subtle maneuver will be very difficult for the attacker to spot. When the attacker completes the out-of-plane maneuver, the defending fighter has regained some of its energy. This allows the defender to, once again, turn harder into the attack, regaining an angular advantage over the higher energy attacker. If the attacker is surprised by the maneuver, a high Yo-Yo defense might even cause an overshoot. Unloaded extension An unloaded extension is a disengagement maneuver often used by the pilot whenever there is enough energy and separation.

The maneuver consists of slipping into a steep, straight dive and applying full thrust. Removing all g-force load from the aircraft causes it to accelerate at a very high rate, allowing the pilot to vastly increase range, or "extend," and possibly to escape. If a defender breaks suddenly, causing the attacker to overshoot, the defender may reverse the turn and move in behind the attacker. An unloaded extension is usually the attacker's best option, using the energy advantage to escape the slower moving defender. An unloaded extension is usually not recommended against a higher energy opponent.However, in many circumstances, such as when an attacker performs a high Yo-Yo too steeply, an unloaded extension is a viable option for the defender.

Scissors The Scissors are a series of turn reversals and overshoots intended to slow the relative forward motion of the aircraft in an attempt to either force a dangerous

overshoot, on the part of the defender, and prevent a dangerous overshoot on the attacker's part. The defender's goal is to stay out of phase with the attacker, trying to prevent a guns solution, while the attacker tries to get in phase with the defender.The advantage usually goes to the more maneuverable aircraft. There are two types of scissor maneuvers, called flat scissors and rolling scissors. Flat scissors Flat scissors, also called horizontal scissors, usually occur after a low speed overshoot in a horizontal direction.

The defender reverses the turn, attempting to force the attacker to fly out in front and to spoil aim. The attacker then reverses, trying to remain behind the defender, and the two aircraft begin a weaving flight pattern. Rolling scissorsRolling scissors, also called vertical scissors, tend to happen after a high speed overshoot from above. The defender reverses into a vertical climb and into a barrel roll over the top, forcing the attacker to attempt to follow. The advantage lies in the aircraft that can pull its nose through the top or bottom of the turn faster.

In battles with aircraft that have a thrust-to-weight ratio of less than one the aircraft will quickly lose altitude, and crashing into the ground becomes a possibility. According to author Mike Spick, "Disengagement from a vertical rolling scissors is best made with a split-s and a lot of hope. Guns defense Guns defense maneuvering, or "guns-D," is the last resort for a defender that fails to out-maneuver the attacker. Guns-D is a series of random changes in the defenders flight path, intended to spoil the attacker's aim by presenting a constantly shifting target, and, hopefully, to maneuver out of

the bullet stream.

It consists of arbitrary speed changes, yaws, skids, pitch-ups, and rolls, often referred to as "jinking," and is very effective at preventing the attacker from achieving a suitable guns solution.However, guns-D maneuvering leaves the defender suceptible to stray bullets and "lucky shot" hits, and is only employed when nothing else works. Fighters aircraft A fighter aircraft is a military aircraft designed primarily for air-to-air combat with other aircraft, as opposed to a bomber, which is designed primarily to attack ground targets by dropping bombs. Fighters are small, fast, and maneuverable. Many fighters have secondary ground-attack capabilities, and some are dual-roled as fighter-bombers; the term "fighter" is also sometimes used colloquially for dedicated ground-attack aircraft.

Fighter aircraft are the primary means by which armed forces gain air superiority over their opponents in battle. Since at least World War II, achieving and maintaining air superiority has been a key component of victory in warfare, particularly conventional warfare between regular armies (as opposed to guerrilla warfare). The purchase, training and maintenance of a fighter fleet represent a very substantial proportion of defense budgets for modern militaries. SU-47 Development Originally known as the S-37, Sukhoi redesignated its advanced test aircraft as the Su-47 in 2002.Officially nicknamed Berkut (Golden Eagle), the Su-47 was originally built as Russia's principal testbed for composite materials and sophisticated fly-by-wire control systems. The aircraft makes use of forward-swept wings allowing superb maneuverability and operation at angles of attack up to 45° or more.

TsAGI has long been aware of the advantages of forward-swept wings, with research including the development of the Tsibin LL and study of the captured Junkers Ju 287 in the 1940s. Forward-swept wings yield a higher maximum lift coefficient, reduced bending moments, and delayed stall when compared to more traditional wing shapes.At high angles

of attack, the wing tips remain unstalled allowing the aircraft to retain aileron control. Unfortunately, forward sweep also induces twisting (divergence) strong enough to rip the wings off an aircraft built of conventional materials. Only recently have composite made the design of aircraft with forward-swept wings feasible. The project was launched in 1983 on order from the Soviet Air Force.

But when the USSR dissolved, funding was frozen and development continued only through funding by Sukhoi. Like its US counterpart, the Grumman X-29, the Su-47 is primarily a technology emonstrator for future Russian fighters. However, Sukhoi is now attempting to market the Su-47 to the Russian military and foreign customers as a production fighter in its own right. The Su-47 is of similar dimensions to previous large Sukhoi fighters, such as the Su-35.

To reduce development costs, the Su-47 borrowed the forward fuselage, vertical tails, and landing gear of the Su-27 family. Nonetheless, the aircraft includes reduced radar signature features (including radar absorbent materials), an internal weapons bay, and space set aside for advanced radar.Though similar in overall concept to the American X-29 research aircraft of the 1980s, the Su-47 is about twice the size and far closer to an actual combat aircraft than the US design. To solve the problem of wing-twisting, the Su-47 makes use of composite materials carefully tailored to resist twisting while still allowing the wing to bend for improved aerodynamic behavior.

Due to its comparatively large wingspan the Su-47 is to be equipped with folding wings in order to fit inside Russian hangars.Like its immediate predecessor, the Su-37, the Su-47 is of tandem-triplane layout, with canards ahead of wings and tailplanes. Interestingly, the Su-47 has two tailbooms of unequal length outboard

of the exhaust nozzles. The shorter boom, on the left-hand side, houses rear-facing radar, while the longer boom houses a brake parachute. Maneuverability The Su-47 has extremely high agility at subsonic speeds, enabling the aircraft to alter its angle of attack and its flight path very quickly while retaining maneuverability in supersonic flight.

The Su-47 has a maximum speed of Mach 1. 6 at high altitudes and a 9g capability. Maximum turn rates, and the upper and lower limits on airspeed for weapon launch, are important criteria in terms of combat superiority. The Su-47 aircraft has very high levels of maneuverability with maintained stability and controllability at extreme angles of attack. Maximum turn rates are important in close combat and also at medium and long range, when the mission may involve engaging consecutive targets in different sectors of the airspace.

A high turn rate of the Su-47 allows the pilot to turn the fighter aircraft quickly towards the next target to initiate the weapon launch. Like most other fighters with fly by wire controls, the Su-47 achieves some of its high maneuverability through relaxed stability The swept-forward wing, compared to a swept-back wing of the same area, provides a number of advantages: * higher lift-to-drag ratio * higher capacity in dogfight maneuvers * higher range at subsonic speed * improved stall resistance and anti-spin characteristics * improved stability at high angles of attack a lower minimum flight speed * a shorter take-off and landing distance Wings The forward-swept midwing gives the unconventional (and characteristic) appearance of the Su-47, earning it the nickname of 'devil' and 'slingshot'. A substantial part of the lift generated by the forward-swept wing occurs at the inner portion

of the wingspan. The lift is not restricted by wingtip stall. The ailerons - the wing's control surfaces - remain effective at the highest angles of attack, and controllability of the aircraft is retained even in the event of airflow separating from the remainder of the wings' surface.The wing panels are constructed of nearly 90% composites. The forward-swept midwing has a high aspect ratio, which contributes to long-range performance. The leading-edge root extensions blend smoothly to the wing panels, which are fitted with deflectable slats on the leading edge; flaps and ailerons on the trailing edge. The all-moving and small-area trapezoidal canards are connected to the leading-edge root extensions. The downside of such a wing design is that it produces strong rotational forces that try to twist the wings off, especially at high speeds.This twisting necessitates the use of a large amount of composites in order to increase the strength and durability of the wing. Despite this strengthening, the plane was initially limited to Mach 1. 6. Recent engineering modifications have raised this limit, but the new limit has not been specified. Nevertheless, it is rumored that the Su-47 prototype recently suffered some manner of wing failure during testing[. As a result, Western analysts speculate that Sukhoi engineers have restored the prototype to a conventional swept-wing layout.Apparently, the engineers reached the same conclusions with regard to the viability of a forward-swept layout as their counterparts at Grumman did twenty years ago with the X-29. Therefore, it is likely that any derivative production aircraft based on Su-47 research will utilize a conventional wing layout. forward-swept wing The illustration shows how the canards on forward swept-wing X-29 with

share the lifting load and reduce drag as compared to a conventional aircraft in the upper diagram.A forward-swept wing is an aircraft wing configuration in which the quarter-chord line of the wing has a forward sweep. The configuration was first proposed in 1936 by German aircraft designers. Perceived benefits of a forward-swept wing design include * Mounting the wings further back on the fuselage, allowing for an unobstructed cabin or bomb bay, as the root of the wingbox will be located further aft, and * Increased maneuverability, due to airflow from wing tip to wing root preventing a stall of the wing tips and ailerons at high angle of attack.Instead, stall will rather occur in the region of the wing root on a forward-swept wing. Possible drawbacks of a forward-swept wing include * When using a conventional metal construction: A reduced divergence speed or, in order to avoid this, an increased wing weight, as wing stiffness needs to be increased. This illustration shows the reverse airflow on forward swept wings vs. the airflow on the swept-back wings. On the forward swept wing, the air tended to flow inward toward the root of the wing rather than outward toward the wing tip as on the swept-back wing.Thrust vectoring is the ability of an aircraft, rocket or other vehicle to direct the thrust from its main engine(s) in a direction other than parallel to the vehicle's longitudinal axis. The technique was originally envisaged to provide upward vertical thrust as a means to give aircraft vertical (VTOL) or short (STOL) takeoff and landing ability. Subsequently, it was realized that using vectored thrust in combat situations enabled aircraft to perform various maneuvers not available to conventional-engined planes.To perform turns, aircraft that use no thrust vectoring must rely on only aerodynamic control surfaces, such as ailerons or flaps;

craft with vectoring must still use control surfaces, but to a lesser extent. Thrust vectoring can convey two main benefits: VTOL/STOL, and higher maneuverability, The thrust vectoring (with PFU engine modification) of ±20° at 30°/second in pitch and yaw will greatly support the agility gained by the forward-swept-wings. Advantages and purpose of aerobatic aircraftMainly the idea of aerobatic aircraft was build for military uses but later on designers developed it for aerobatic competition or air shows. In military air force, aerobatics are shown in fighters where the aim of those fighter are in air combats or dogfights where high performance maneuvers are required. Requirements for construction of aerobatic aircraft Requirement: High power to weight ratio Strong body can handle the stress of high performance maneuver Low stall speed