3 ms·

Just so we're clear, there's practically no such thing as an "unstallable plane". If some pilot believes that then their license should be revoked. Even jet eng

Just so we're clear, there's practically no such thing as an "unstallable plane". If some pilot believes that then their license should be revoked. Even jet engines can experience stalls internally on the compressor blades, and even helicopters can experience stalls on their retreating blade. I would compare it to someone believing that their car cannot possibly lose traction. Exceptions, which of course must exist, include some fly-by-wire setups which limit the actuation of flight surfaces so that it should be theoretically impossible to put an aircraft in that situation, and rumored properties of some abnormal constructions like the An-2. Although even there you should repeatedly get comfortable with what happens in/around a stall, at least in simulators. The fact that air started to separate and the end of the wing, and not at the root, is scary. It means the pilot wouldn't get the normal warning in the form of airframe shaking. Bad modification.

golergka 2y ago
Edit: It seems that I completely misread what Wikipedia said, disregard this comment.
- H8crilA 2y ago
  https://aviation.stackexchange.com/questions/65718/what-makes-the-antonov-an-2-have-no-stall-speed https://aviation.stackexchange.com/questions/65718/what-make... There are many ways of totalling a plane beyond a stall.
- cjbgkagh 2y ago
  Over 18k An-2 were produced during the time of 1947-2001. It’s an unusual plane due how old it is and that many are still in operation so general stats should take that into account. It’s well known for being nearly impossible to stall with a stall speed of 30 knots - if it does stall it’ll sink at the rate of a parachute which is still faster than you’d want to hit the ground for a landing. It’s also easy to pick up that speed by dipping the nose. If someone crashes an an-2 by stalling it they had to really work hard to do it. Any pilot that did this would be considered unsafely inept to an almost unimaginable degree. This article is the first I'm hearing of a Cessna 185 being considered unstallable and I do wonder it that title was picked for engagement. Float planes are extra dangerous with more that can go wrong and less margins for safety.
  - Tuna-Fish 2y ago
    Wasn't AN-2 the plane where the manual advises that if you need to land and cannot see your landing site, you should fly low and slow and intentionally stall the plane?
    - cjbgkagh 2y ago
      I don't know but that would make sense, landing at the speed of a parachute is better than crashing. Not sure on the exact numbers but a parachute sink rate of 5m/s is over the usual landing touch down sink rate of 1m/s. I would guess at that rate there might still be some damage to crew and airframe. If done skillfully I would image it would be possible to trade some forward speed for a slower sink rate right before touchdown to make for much softer landing.
sfeng 2y ago
Canard aircraft, for example, stall the canard first, resulting in the nose dropping, preventing the main wing from ever stalling.
- maximilianburke 2y ago
  The main wing can still be stalled in a canard; it’s not easy but it is possible and when it happens it’s almost unrecoverable because the canard will be stalled too and no flying surfaces will have sufficient lift to correct the condition. It’s a condition called “deep stall”
  - brazzy 2y ago
    IIRC non-canard aircraft can have this happen when the stall causes the plane to fall at an angle where the wake turbulence of the wings covers the elevators.
  - Wistar 2y ago
    Usually in a cross-controlled “slip” where the fuselage is held at a fairly dramatic angle relative to the slipstream (relative wind) and the fuselage “blanks out” one side of the main wing.
- renhanxue 2y ago
  This is far from universally true. The Saab 37 Viggen fighter jet (which was also the first series produced canard aircraft) is capable of departing from controlled flight into a stalled attitude in no less than five different ways, according to its flight manual: > If the angle of attack exceeds the permitted limits, some yaw disturbances appear around alpha 25-28°, and at alpha 28-30° there are weak pitch-up tendencies. If the stick is moved forward to counter the pitch-up, the aircraft returns to normal alpha, possibly after overshooting up to alpha ~50°. Note that the angle of attack instrument only shows the area -4° to +26°. > If the stick movement forward at the pitch-up is too small or is made too late, such that the angle of attack does not immediately decrease, the aircraft departs into superstall or spin. If the pitch-up occurs without aileron input, the departure usually results in superstall. If the pitch-up occurs with any aileron input active, the aircraft is affected by adverse yaw and the likelihood of a spin increases. In addition to the superstall, the aircraft has two spin modes, in the flight manual referred to as flat and oscillating. The difference is basically the rotation speed and if there are oscillations in pitch and/or roll or not. The recovery is pretty conventional: > In superstall or spin the pitch authority is good, which eases recovery. Aileron input results in adverse yaw, that is to say rolling right gives a yaw to the left and vice versa. Rudder authority is negligible. > Recovery from superstall and oscillating spin is accomplished by moving the stick to a position somewhat forward of the neutral pitch position, with ailerons and rudder neutral. To recover from a flat spin, the yawing rotation must be stopped first, which is accomplished with neutral pitch and full roll input in the direction of the rotation ("stick into the spin"). When the rotation has just about ceased, recovery is accomplished with neutral ailerons and the stick somewhat forward of neutral, just like when recovering from superstall and oscillating spin. In addition to regular stalled attitudes though, the aircraft also exhibits another stalled attitude with autorotation, the "plunging spiral" (sv. störtspiral) which can also be encountered in two variants. I'm honestly not sure how exactly it works aerodynamically. The flight manual says: > In certain adverse dynamic scenarios, the aircraft can enter an uncontrolled attitude of the autorotating type, here called plunging spiral . The plunging spiral, which can be either right side up or inverted, is considered to be the potentially most dangerous form of uncontrolled flight that has been discovered during the spin tests of aircraft 37. > The most common form of the plunging spiral is the inverted one. The following attitudes/maneuvers repeatably result in an inverted plunging spiral: 1) somersault into inverted position from oscillating spin (for example while attempting to recover from a spin with the stick fully forward), 2) stalling the tailfin through so-called "knife edge flying". The inverted plunging spiral is characterized by: 1) negative load factor (-1 to -3 G) 2), low nose, 3) very high rate of rotation in the roll axis (≥ 200°/s), 4) high sink rate (≥ 150 m/s). > Moving the stick back and/or aileron input to either side tends to increase the rate of the roll rotation. The rotation can be stopped by moving the stick fully forward with no aileron input. When the rotation has ceased, the stick is moved back to neutral pitch, and the aircraft recovers to controlled flight. > The aircraft only departed into a non-inverted plunging spiral on a few occasions during the spin tests. It has not been possible to define any repeatable attitude or maneuver that results in a non-inverted plunging spiral. During the spin tests the non-inverted plunging spiral only occurred on the following two occasions (not repeatable): 1) when recovering from an inverted superstall, 2) when recovering from an oscillating non-inverted spin. The non-inverted plunging spiral is characterized by: 1) positive load factor (+1 to +3 G), 2) low nose, 3) very high rate of rotation in the roll axis (≥ 200°/s), 4) high sink rate (≥ 150 m/s). > In a non-inverted plunging spiral, aileron inputs have no effect. Instead, the roll rotation must be stopped by pulling gently back on the stick until the rotation ceases. When the rotation has ceased, the stick is moved forward to the neutral pitch position and the aircraft recovers into controlled flight.
t0mas88 2y ago
Very bad modification. And wrong (but natural) response from the pilot trying to pick up the dropping wing with aileron input. That would have made the asymmetric stall worse.

golergka 2y ago

Edit: It seems that I completely misread what Wikipedia said, disregard this comment.

H8crilA 2y ago
https://aviation.stackexchange.com/questions/65718/what-makes-the-antonov-an-2-have-no-stall-speed https://aviation.stackexchange.com/questions/65718/what-make... There are many ways of totalling a plane beyond a stall.
cjbgkagh 2y ago
Over 18k An-2 were produced during the time of 1947-2001. It’s an unusual plane due how old it is and that many are still in operation so general stats should take that into account. It’s well known for being nearly impossible to stall with a stall speed of 30 knots - if it does stall it’ll sink at the rate of a parachute which is still faster than you’d want to hit the ground for a landing. It’s also easy to pick up that speed by dipping the nose. If someone crashes an an-2 by stalling it they had to really work hard to do it. Any pilot that did this would be considered unsafely inept to an almost unimaginable degree. This article is the first I'm hearing of a Cessna 185 being considered unstallable and I do wonder it that title was picked for engagement. Float planes are extra dangerous with more that can go wrong and less margins for safety.
- Tuna-Fish 2y ago
  Wasn't AN-2 the plane where the manual advises that if you need to land and cannot see your landing site, you should fly low and slow and intentionally stall the plane?
  - cjbgkagh 2y ago
    I don't know but that would make sense, landing at the speed of a parachute is better than crashing. Not sure on the exact numbers but a parachute sink rate of 5m/s is over the usual landing touch down sink rate of 1m/s. I would guess at that rate there might still be some damage to crew and airframe. If done skillfully I would image it would be possible to trade some forward speed for a slower sink rate right before touchdown to make for much softer landing.

sfeng 2y ago

Canard aircraft, for example, stall the canard first, resulting in the nose dropping, preventing the main wing from ever stalling.

maximilianburke 2y ago
The main wing can still be stalled in a canard; it’s not easy but it is possible and when it happens it’s almost unrecoverable because the canard will be stalled too and no flying surfaces will have sufficient lift to correct the condition. It’s a condition called “deep stall”
- brazzy 2y ago
  IIRC non-canard aircraft can have this happen when the stall causes the plane to fall at an angle where the wake turbulence of the wings covers the elevators.
- Wistar 2y ago
  Usually in a cross-controlled “slip” where the fuselage is held at a fairly dramatic angle relative to the slipstream (relative wind) and the fuselage “blanks out” one side of the main wing.
renhanxue 2y ago
This is far from universally true. The Saab 37 Viggen fighter jet (which was also the first series produced canard aircraft) is capable of departing from controlled flight into a stalled attitude in no less than five different ways, according to its flight manual: > If the angle of attack exceeds the permitted limits, some yaw disturbances appear around alpha 25-28°, and at alpha 28-30° there are weak pitch-up tendencies. If the stick is moved forward to counter the pitch-up, the aircraft returns to normal alpha, possibly after overshooting up to alpha ~50°. Note that the angle of attack instrument only shows the area -4° to +26°. > If the stick movement forward at the pitch-up is too small or is made too late, such that the angle of attack does not immediately decrease, the aircraft departs into superstall or spin. If the pitch-up occurs without aileron input, the departure usually results in superstall. If the pitch-up occurs with any aileron input active, the aircraft is affected by adverse yaw and the likelihood of a spin increases. In addition to the superstall, the aircraft has two spin modes, in the flight manual referred to as flat and oscillating. The difference is basically the rotation speed and if there are oscillations in pitch and/or roll or not. The recovery is pretty conventional: > In superstall or spin the pitch authority is good, which eases recovery. Aileron input results in adverse yaw, that is to say rolling right gives a yaw to the left and vice versa. Rudder authority is negligible. > Recovery from superstall and oscillating spin is accomplished by moving the stick to a position somewhat forward of the neutral pitch position, with ailerons and rudder neutral. To recover from a flat spin, the yawing rotation must be stopped first, which is accomplished with neutral pitch and full roll input in the direction of the rotation ("stick into the spin"). When the rotation has just about ceased, recovery is accomplished with neutral ailerons and the stick somewhat forward of neutral, just like when recovering from superstall and oscillating spin. In addition to regular stalled attitudes though, the aircraft also exhibits another stalled attitude with autorotation, the "plunging spiral" (sv. störtspiral) which can also be encountered in two variants. I'm honestly not sure how exactly it works aerodynamically. The flight manual says: > In certain adverse dynamic scenarios, the aircraft can enter an uncontrolled attitude of the autorotating type, here called plunging spiral . The plunging spiral, which can be either right side up or inverted, is considered to be the potentially most dangerous form of uncontrolled flight that has been discovered during the spin tests of aircraft 37. > The most common form of the plunging spiral is the inverted one. The following attitudes/maneuvers repeatably result in an inverted plunging spiral: 1) somersault into inverted position from oscillating spin (for example while attempting to recover from a spin with the stick fully forward), 2) stalling the tailfin through so-called "knife edge flying". The inverted plunging spiral is characterized by: 1) negative load factor (-1 to -3 G) 2), low nose, 3) very high rate of rotation in the roll axis (≥ 200°/s), 4) high sink rate (≥ 150 m/s). > Moving the stick back and/or aileron input to either side tends to increase the rate of the roll rotation. The rotation can be stopped by moving the stick fully forward with no aileron input. When the rotation has ceased, the stick is moved back to neutral pitch, and the aircraft recovers to controlled flight. > The aircraft only departed into a non-inverted plunging spiral on a few occasions during the spin tests. It has not been possible to define any repeatable attitude or maneuver that results in a non-inverted plunging spiral. During the spin tests the non-inverted plunging spiral only occurred on the following two occasions (not repeatable): 1) when recovering from an inverted superstall, 2) when recovering from an oscillating non-inverted spin. The non-inverted plunging spiral is characterized by: 1) positive load factor (+1 to +3 G), 2) low nose, 3) very high rate of rotation in the roll axis (≥ 200°/s), 4) high sink rate (≥ 150 m/s). > In a non-inverted plunging spiral, aileron inputs have no effect. Instead, the roll rotation must be stopped by pulling gently back on the stick until the rotation ceases. When the rotation has ceased, the stick is moved forward to the neutral pitch position and the aircraft recovers into controlled flight.

t0mas88 2y ago

Very bad modification. And wrong (but natural) response from the pilot trying to pick up the dropping wing with aileron input. That would have made the asymmetric stall worse.