Cobra maneuver

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Pugachev's Cobra maneuver is one of the tests for supermaneuverability, here performed by a Su-27.

In aerobatics the Cobra maneuver, also known as just the Cobra, is a dramatic and demanding maneuver in which an airplane flying at a moderate speed suddenly raises the nose momentarily to the vertical position and slightly beyond, before dropping it back to normal, effectively making the plane a full body air brake which momentarily stalls the plane.

The maneuver relies on the ability of the plane to be able to quickly change alpha without overloading the airframe[1] and powerful engine thrust to maintain approximately constant altitude through the entire move.[2] It is an impressive maneuver to demonstrate an aircraft's pitch control authority, high alpha stability and engine-versus-inlet compatibility, as well as the pilot's skill.

Although the maneuver is mainly performed at air shows[3] it has use in close range air combat as a last ditch maneuver to make a pursuing plane overshoot.[1][4] There is currently no widely spread or readily available evidence of the Cobra being used in real combat, although, there are records of it being used during mockup-dogfights[1] and during border protection.[5]

Names[edit]

The maneuver goes by many names around the globe but it is most often referred to as the Cobra maneuver in the respective language.[6] The origin for the name Cobra is unknown but it could refer to the plane displaying its top and bottom profile, much like a cobra spreading its shield.

Other notable names includes: Pugachev's Cobra (alternative the Pugachev Cobra), which is named after Viktor Pugachev, the first pilot to bring the maneuver to the public eye. Short parade (Swedish: Kort parad), the original Swedish name for the maneuver, probably referring to the way the plane stands up during the maneuver. Zero speed maneuver (Arabic: مناورة السرعة صفر), the Syrian name for the maneuver, referring to the way the plane loses speed during the maneuver.

History[edit]

The maneuver first came to the public's attention when the Soviet test pilot, Viktor Pugachev, performed it at the Le Bourget Paris air show in 1989 using a Sukhoi Su-27.[2] As this maneuver was largely unknown to the public previous to this the maneuver was quickly named after Pugachev. But apparently Pugachev was not the first Soviet pilot who had performed the Cobra. Another Soviet test pilot, by the name of Igor Volk, did the Cobra previous to this when he tested aircraft behavior at high super-critical angles of attack, up to around 90°.[7]

However the Soviets were not the inventors of the Cobra.

Sweden[edit]

The Saab 35 Draken which invented the maneuver.

Several decades prior to Pugachev showing off his cobra, during the early 1960's, the maneuver was performed by Swedish pilots flying the Saab 35 fighter jet.[8] It was invented during training on how to recover from what is called a "super stall" in Swedish, which simplified can be described as an uncontrollable stall which appears on planes with specific features when pulling high alpha numbers.[9] Super stall plagued the early years of the Saab 35's service life, leading to several deaths, which in turn lead the Swedish air staff to implement extra training on how to counteract and recover from it.[8] It is currently not known exactly when and how the Swedish invented or discovered the Cobra but it was during this intense training period the Swedish pilots learned how to do it. The maneuver was pretty simple. When pulling high alpha and the pilot noticed that he was going into super stall he would then pull negative alpha to get out of it. The effects this maneuver had on the aircraft's speed was noted and pilots started to purposely use it as a way to lower speed.[8]

The Swedes named the maneuver "kort parad", or "short parade" in English, which probably refers to the way the plane stands up during the maneuver. The Swedish pilots quickly started to theorize on how to use this move in combat as a way to get a pursuing aircraft to overshoot and it didn't take long until it was proven viable during mockup-dogfights.[8][1] In real combat, depending on the situation and the execution of the maneuver, it could be used to confuse the enemy by making it lose the target or to overshoot which would give the pursued pilot the opportunity to either flee from combat or to set up a new engagement. However the maneuver was tricky to apply to anything more than a last-ditch maneuver as with bad execution the aircraft's speed after the maneuver made it an easy target.[10]

The maneuver originated with the Bråvalla Air Force Wing, who were the first wing to receive the Saab 35 fighter plane. As the plane was in time adopted by other wings, so was the maneuver. The Scania Air Force Wing apparently called the maneuver "Wacka", which has no real meaning in Swedish.[1]

Since Sweden shared a large portion of its border with the Soviet union during the cold war, the Saab 35's had to regularly meet up and escort Soviet planes away from the Swedish border. Sometimes these meetings would result in non-combat dogfights, which were either of playful or threatening nature.[8] Apparently the Cobra maneuver was used during some of these engagements to surprise of the Soviets.[5] Later in the Saab 35's service life the maneuver was used as a secret weapon against the more advanced Saab 37 fighter plane in mockup-dogfights. The Saab 37 was unable to effectively enter super stalls and therefore its pilots did not receive any major training against it. Due to this the Cobra maneuver was unknown to a lot of Saab 37 pilots prior to facing it in combat.[1] Due to the interesting nature of the move, some Saab 37 pilots tried to apply it on the Saab 37, but to their dismay it was unable to effectively do it above speeds of 350 km/h as the Saab 37 couldn't safely take the necessary g's to do it above that, effectively rendering it useless in combat.[1]

When the Saab 35 went out of service so did the maneuver as the next generations of Swedish war planes, the Saab 37 and the Saab 39, couldn't effectively use it in combat. Due to the secrecy of the cold war era and other factors the Swedish Cobra was largely unknown to the world until some former Saab 35 and 37 pilots brought it up years later in books[1][8] and articles[5][10], although this was way after the Soviets had already been credited with its discovery.

Austria[edit]

According to a video by the name of "Tisoe", which was uploaded by the Scania Air Force Wing comrade association (Swedish: F10 Kamratförening), the Swedish Cobra was taught to Austrian pilots training on the Saab 35 in Sweden.[11] Its unknown if the Austrians used this as a combat maneuver or just as training against super stall.

Syria[edit]

Beyond Sweden, Syria also discovered the maneuver prior to the Soviets. In 1961 when Syria broke loose from the United Arab Republic, they were left with a very weak air force. Due to this, the Syrians had to order new combat aircraft, which resulted in the Mig-21F-13 in June 1962.[12] Once the aircraft had arrived and been set up a problem became apparent. All the unit commanders had been selected based on political associations and loyalty to superiors, instead of knowledge in air combat. Due to this, the newly established commanders were over-reliant on advice from about 30 Soviet advisers assigned to the Syrian air force to help them work with the new planes. Due to this era of power over knowledge, a handful of pilots with powerful connections, were able to disregard Soviet advises and orders from their commanders, which enabled them to do whatever they wanted.[12]

One of these pilots was a man by the name of Mohammad Mansour, a then novice MiG-21-pilot fresh from conversion course in the USSR. His older brother, a man by the name Fayez Mansour, had deep connections up the chain of command in Damascus. Thus, Mohammad began challenging advises from Soviet advisors and demanding greater operational flexibility for himself and other pilots of his unit.[12]

During Mohammed's first clashes with the Israeli air force, he learnt that there was a need for an effective defensive maneuver for close combat that made a pursuing plane overshoot. His initial solution was based on Soviet manuals and consisted of rapid descending turns followed by a sudden activation of the afterburner and a climb. However, during a test-flight in early 1967, Mohammad inadvertently pitched the nose of his MiG-21 too hard, so that the forward movement of his aircraft nearly stopped. As a reaction he engaged the afterburner of his MiG which ended with the plane standing vertical on the verge of stalling out of control. Mohammad managed to recover the plane from the state, just in time to prevent a crash. To prevent this from happening again, he decided to try to replicate the maneuver in a controlled manner, this time by engaging the afterburner beforehand, as the Tumansky R-11 engine of the Mig-21 had to spool for full effect. After successful replication of the maneuver it became clear that this was the defensive maneuver for close combat that he had been looking for.[12]

The Syrians came to name the Cobra the "zero speed maneuver" (Arabic: مناورة السرعة صفر, "munawarat alsureat sifr"). Mohammad soon saw combat with the Israeli air force but never got to use his Cobra.[12] The Cobra quickly became a standard part of defensive tactics for Syrian Mig-21's.

Pakistan and Egypt[edit]

With time, as different air forces were stationed in Syria, the maneuver spread to both the Pakistan and Egyptian air force, who also started using it as a standard defensive maneuver for their MiG-21's, as well on their F-7's.[12]

There is some indication that the Cobra maneuver was performed during combat by an Egyptian pilot during the Yom Kippur War, but it is based on the quote of an Israeli pilot and doesn't mention anything more than an Egyptian MiG-21 standing on his tail when trying to evade an attack.[12]

Soviet Union[edit]

It's currently unknown when the cobra maneuver first came to the Soviet Union's attention. It's possible they first learnt about it from the engagements with the Swedish over the Baltic Sea during the 1960's but one story says that the Soviets during their visits in Egypt during the period 1970-1972, saw the maneuver being performed by Egyptian MiG-21 pilots. This apparently followed them back to the USSR.

As there is currently no known material on the Soviets performing the maneuver prior to the 1980's, it's possible the maneuver was "rediscovered" by pilots like Viktor Pugachev or Igor Volk when testing advanced Soviet planes like the Su-27. It's fair to say the Russians have used it for the better, using it to push the development of supermaneuverability and to amaze audiences at air shows, instead of using it in actual combat.

Another historical note of interest is that despite how advanced modern multirole and air superiority fighters are, there are very few of them can perform the Cobra. Those that can are mainly from Russia or of experimental nature.

Description[edit]

In the case of the Su-27, the pilot initially disengages the angle of attack limiter of the plane, normally set at 26°.[2] This action also disengages the g limiter. After that the pilot pulls back on the stick hard. The aircraft reaches 90–120° angle of attack with a slight gain of altitude and a significant loss of speed. When the elevator is centered, the drag at the rear of the plane causes torque, thus making the aircraft pitch forward. At that time the pilot adds power to compensate for the lift loss.[citation needed]

In a properly performed Pugachev's Cobra, the plane maintains almost straight flight throughout the maneuver. The plane does not roll or yaw in either direction. Proper entry speed is significant because, if entering at too low a speed, the pilot might not be able to accomplish the maneuver. Entering at too high a speed might result in airframe damage due to the high g-force or the pilot losing consciousness.[citation needed]

While Pugachev's Cobra can be executed using only standard aerodynamic controls, it could be achieved more easily with modern thrust vectoring such as the case of F-22 Raptor which utilizes 2D thrust vectoring. In either case it is an example of supermaneuverability,[13] specifically poststall maneuvering. The Herbst maneuver and the helicopter maneuver are examples of similar post-stall maneuvers that are often carried out by 4.5th Generation and 5th Generation fighter aircraft, often employing thrust vectoring.[14]

Use in combat[edit]

The Sukhoi Su-27 is capable of the maneuver.

If pursued by an enemy fighter in a dogfight, by executing the Cobra, a sufficiently closely pursued aircraft may suddenly slow itself to the point that the pursuer overshoot its, allowing the previously pursued aircraft to complete the Cobra behind the other. This may give the now-pursuing aircraft an opportunity for firing its weapons, particularly if a proper pointing aspect (facing toward the former pursuer) can be maintained. Due to the speed loss when performing a Cobra, maintaining weapons on target may require the use of thrust vectoring and/or canard control surfaces. Otherwise the maneuver may also allow the pursued plane to flee as the overshooting attacker may lose track of the target.

The disadvantage of performing this maneuver is that it leaves the airplane in a low speed/low energy state, which can leave it vulnerable to attack from opposing aircraft. It can also be countered by maneuvers such as high yo-yo.[citation needed]

The maneuver is also potentially a defense against radar, as the sudden change in velocity can often cause Doppler radars to lose their lock on the target.[15] Doppler radars often ignore any objects with a near zero velocity to reduce ground clutter. The cobra maneuver's sudden change to near zero velocity often results in the target being momentarily filtered off as ground clutter, making it difficult for the radar to lock onto the target, or breaking the target lock if already established. Although there is no available documentation of this being tested beyond theory.

The Cobra maneuver has been used in mockup-dogfights but there is little to no known documentation of it being used in actual combat. The mockup-dogfights were performed by planes using 1950's technology which differs heavily from modern planes capable of the Cobra. Existing material of these mockup-dogfights does not cover the elements of the engagements prior to, and after the use of the Cobra, which would be useful in theorizing its usefulness in modern combat. That being said, it was, according to existing material, useful as a combat move during the third and fourth-generations of jet fighters.[1]

Examples of aircraft capable of the maneuver[edit]

Production aircraft[edit]

Experimental aircraft[edit]

See also[edit]

References[edit]

  1. ^ a b c d e f g h i j Ulf Edlund & Hans Kampf (2009). System 37 Viggen, FLYGHISTORISK REVY. Sweden: Svensk flyghistorisk förening. pp. 212, 213.
  2. ^ a b c d e Mike Spick (2002). The Illustrated Directory of Fighters. St. Paul, Minnesota: MBI Publishing Company. p. 442. ISBN 0-7603-1343-1. Retrieved 29 October 2011.
  3. ^ "Example of the cobra being performed at an air show".
  4. ^ Crane, David. "Air-to-Air Fighter Combat Application of Pugachev's Cobra Maneuver: Busting the Western Myth". Defense Review. Retrieved 14 January 2012.
  5. ^ a b c "F10 Kamratförening J 35 Draken". www.f10kamratforening.se. 20 October 2019.
  6. ^ See for example the German article.
  7. ^ Hall, Rex; Shayler, Davide; Vis, Bert (2005). Russia's Cosmonauts: Inside the Yuri Gagarin Training Center. Chichester, UK: Praxis Publishing. pp. 335–6. ISBN 0-387-21894-7.
  8. ^ a b c d e f Ulf Edlund & Hans Kampf (2005). Draken 50 år, FLYGHISTORISK REVY. Sweden: Svensk flyghistorisk förening.
  9. ^ Speciell förarinstruktion för J 35B Draken. Sweden: Swedish air force. pp. 73, 74.
  10. ^ a b "Article on how it was to fly the Saab 35".
  11. ^ "F10 kamratförening: filmer, clip Tisoe".
  12. ^ a b c d e f g h "THE UNKNOWN STORY OF THE SYRIAN MIG-21 PILOT WHO DEVELOPED THE COBRA".
  13. ^ Malcolm J. Abzug; E. Eugene Larrabee (2005). Airplane Stability and Control: A History of the Technologies that Made Aviation Possible. pp. 157–161. ISBN 978-0-521-80992-4.
  14. ^ Benjamin Gal-Or. "Vectored Propulsion, Supermaneuverability, and Robot Aircraft". Springer Verlag, 1990, ISBN 0-387-97161-0, ISBN 3-540-97161-0.
  15. ^ Bill Sweetman, Aviation Week & Space Technology, Jun 24, 2013, quoting Sukhoi chief test pilot Sergey Bogdan
  16. ^ Mitko Ian. "Sukhoi SU-35 fighter has all the right moves at Paris Air Show". Gizmag.com. Retrieved 18 June 2013.
  17. ^ https://www.youtube.com/watch?v=eNY9sCgcyU0
  18. ^ John Dovishaw, Russia Mig does Cobra Maneuver at Dayton Airshow, retrieved 8 February 2019
  19. ^ Venci Dimitrov, Миг-29 управляван от Ген. Радев /Авиошоу 2014, летище София/, retrieved 8 February 2019
  20. ^ "Cobra Maneuver ?". International journal of turbo & jet-engines. 11. Retrieved 23 March 2011.
  21. ^ https://www.youtube.com/watch?v=RVXFNakwDiw

External links[edit]