Long before the Russian Su-27, the Saab J35 Draken was already performing a maneuver similar to the Cobra, revealing unexpected capabilities in terms of agility and aeronautical innovation.
The Saab J35 Draken, designed in the 1950s, is often mentioned for its double delta wing and supersonic performance. However, a chance discovery by test pilots in the 1960s highlighted an astonishing capability: the ability to perform a high angle of attack maneuver, similar to the future Cobra of the Soviet Su-27, which was publicly unveiled in the 1980s. This maneuver consists of abruptly pitching the aircraft up to 90° of angle of attack before resuming controlled flight. This aerodynamic behavior, unexpected for an aircraft of its generation, highlighted the Draken’s experimental potential and influenced the understanding of high-angle-of-attack maneuverability. The ability to explore such flight regimes had consequences for Swedish operational doctrine and the international perception of the limits of fighter aircraft at the time.
A unique aircraft and a research context
The Saab J35 Draken was the first production fighter aircraft to feature a double delta wing, which allowed it to combine supersonic stability with low-speed maneuverability. Designed to intercept Soviet bombers at high altitude, it reached Mach 2 and could operate from very short runways, in accordance with Swedish dispersion doctrine.
During flight tests, pilots observed an unexpected phenomenon: when the aircraft was flown at a very high angle of attack, it maintained sufficient lift thanks to the vortices generated by the inner wing. Unlike many contemporary fighters, the Draken did not stall abruptly. This paved the way for unprecedented maneuvers, similar to so-called “post-stall” maneuvers, long considered unattainable for production aircraft.
A maneuver similar to the Cobra
The Cobra maneuver consists of pulling sharply on the stick, pitching the aircraft up more than 90° relative to the airflow, then quickly returning it to flight attitude. When performed correctly, it allows for a sudden loss of speed and a change of situation in close combat.
With the Draken, test pilots discovered that under well-controlled conditions, the aircraft could perform a sudden climb at high angle of attack, stabilize briefly in a near-vertical nose-up position, and then return to level flight without loss of control. Tests showed that this maneuver was repeatable, even though it was not included in the tactical manuals.
This phenomenon was based on the generation of vortices by the double delta wing. These maintained lift and partial stability despite angles of attack well beyond the conventional limits of the time.
Measured flight performance
Technically, the Saab J35 could reach an angle of attack of 80 to 85° during the maneuver, while maintaining a certain degree of control. However, performing the maneuver required a significant loss of speed, reducing the available thrust and exposing the aircraft to temporary vulnerability.
The airframe, designed to withstand high load factors (up to +8 g), could handle the mechanical stresses generated by these unusual maneuvers. The aircraft could return to stable flight in a matter of seconds, provided the pilot anticipated the maneuver accurately.
In comparison, the Su-27 Flanker, designed two decades later, benefited from electric flight controls and a much higher thrust-to-weight ratio, allowing it to perform the Cobra in a more controlled and spectacular manner. The fact that the Draken was able to approach these performances much earlier highlights the relevance of its aerodynamic design.
How it works: the aerodynamics of the double delta wing
The key to this maneuver lay in the unique design of the double delta wing.
- The highly swept inner section generated stable vortices at high angles of attack, delaying stall.
- The outer section, which was less pronounced, increased lift at low speeds and allowed the pilot to maintain a certain degree of lateral control.
These vortex flows formed an aerodynamic “bubble” that kept the nose of the aircraft pitched up without causing the lift to collapse completely. This behavior was still poorly understood in the 1960s, when fluid dynamics studies were limited by the available digital tools. The experience gained with the Draken helped to better understand the aerodynamics of extreme angles of attack, foreshadowing the research that would lead to the fly-by-wire systems of fourth-generation aircraft.
Technological consequences
The existence of this maneuver on an aircraft designed in the late 1950s demonstrated that turbulent flow dynamics could be exploited to push the limits of maneuverability. Even though the Draken was not equipped with digital flight controls, it already showed the potential of this type of flight regime.
For Saab, these observations fed into the design of the Saab 37 Viggen, then the Saab JAS 39 Gripen, both designed for excellent agility and safe operation at high angles of attack. More broadly, the example of the Draken illustrated the ability of a small manufacturer to anticipate solutions that would only be fully exploited decades later by the major aeronautical powers.
Operational and military consequences
Tactically, the Cobra maneuver was not taught as a combat technique within the Flygvapnet. The risks associated with loss of speed and temporary vulnerability limited its operational value. However, it demonstrated that the Draken could withstand unexpected situations without immediately leaving its flight envelope.
In close combat, this capability theoretically offered the possibility of overtaking an opponent, opening up a window of opportunity to fire. In practice, the air force preferred to focus on supersonic speed and rapid climb, the aircraft’s primary missions as an interceptor.
Nevertheless, the existence of this maneuver influenced the advanced training of test pilots and served as the basis for tactical experiments. It also confirmed the structural and aerodynamic robustness of the Draken, which remained operational in several European countries for more than 40 years.
A pioneering figure in aviation history
The promotion of the Cobra by Soviet pilots in the 1980s, particularly during demonstrations of the Su-27, made a strong impression on the public and Western observers. However, the Saab Draken had explored this maneuver long before, in a more discreet and less publicized setting.
This precedence highlights Saab’s conceptual advance, which had created an aircraft that exceeded initial expectations. The Draken’s Cobra remains a technical curiosity, but also an important milestone in the history of aeronautical research into extreme flight regimes.
A lasting lesson for modern aeronautics
The fact that a 1960s interceptor was able to perform a maneuver associated with fourth-generation fighters reminds us of an obvious fact: some innovations emerge by accident, thanks to the daring of test pilots and the intuition of engineers. The Saab J35 Draken demonstrates that Swedish engineering, in seeking to combine supersonic performance and operational flexibility, produced an aircraft that far exceeded its specifications.
In an aeronautical world dominated by American and Soviet giants, the Draken experience highlights that the capacity for innovation depends not only on the size of budgets, but also on the originality of the technical solutions adopted.
War Wings Daily is an independant magazine.