The J-35 had an inherent instability that could lead to superstall, a phenomenon attributed to Draken’s special wing planform.
This post features an amazing video of Swedish Air Force J-35 (SK 35C) Draken trainers executing the Cobra Maneuver. The Swedish Air Force engaged the Russians in combat in the early stages of the Cold War by employing this tactic.
Notably, Draken’s unique wing planform was thought to be the cause of the J-35’s inherent instability, which might result in a superstall.
Depending on how it was entered, there were two main ways to superstall, as Jan Jorgensen describes in his book Saab 35 Draken. In the first mode, the aircraft pitched between a nose-up and a nose-down attitude. The occasional yaw and sideslip went along with it, but there was no noticeable rolling motion. In the second mode, the aircraft was stabilized at a 50–60-degree angle of attack. In all cases, the aircraft fell at a speed of about 80 meters per second, nearly straight down. Additionally, the Draken could enter an outside, or inverted, superstall. Even in cases where recovery was successful, there was a huge loss of altitude in any superstall.
The superstall was recovered by holding the stick initially fully back and then pushing it full forward when the aircraft nosed down. In the stabilized superstall the stick was just pushed fast fully forward. The stick was centered when the nose was straight down. It had to be done in due time to prevent the aircraft from entering an outside superstall.
Between 1959 and 1987, a total of 179 Draken superstalls were reported in the Swedish Air Force. 35 of these resulted in a crash and destruction of the aircraft. Four pilots were killed in these accidents, two failed to eject and two ejected unsuccessfully. Because of the high risks involved in the superstall, Draken pilots of all nations received special recovery training in Sweden using both simulators and SK 35C trainers equipped with an anti-spin parachute.
But as the video below demonstrates, if managed properly, the Draken was capable of performing the maneuver that was subsequently dubbed the “Pugachev’s Cobra.”
