The J-35 had an inherent instability that could lead to superstall, a phenomenon attributed to the Draken’s special wing planform.
The impressive video in this post shows Swedish Air Force J-35 (SK 35C) Draken trainers performing the Cobra Maneuver.
Noteworthy the J-35 had an inherent instability that could lead to superstall, a phenomenon attributed to the Draken’s special wing planform.
As Jan Jorgensen explains in his book Saab 35 Draken there were two main modes of superstall depending on the way it was entered. In the first mode the aircraft pitched between nose up and nose down attitudes. It was accompanied by occasional yaw and sideslip but without any noteworthy rolling motion. In the second mode the aircraft was stabilized in 50-60 degrees angle-of-attack. In both situations the aircraft fell almost straight down at a rate of some 80 m/s. The Draken could also enter an inverted (outside) superstall. In any superstall the loss of altitude was excessive even if recovery was successful.
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 centred 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 anti-spin parachute.
However as the following video shows, if handled correctly the Draken could perform the maneuver that was later called the “Pugachev’s Cobra.”
Photo credit: Dario Leone