4 ms·

Can't a skilled pilot in a plane with appropriate control fly in a straight line at very dramatic roll? Or is this article talking about at optimal lift efficie

Can't a skilled pilot in a plane with appropriate control fly in a straight line at very dramatic roll? Or is this article talking about at optimal lift efficiency? Just watch this video and try to tell me how the pilot is feeling a down force orthogonal to the floor of his plane: https://digg.com/2019/kyalami-drift https://digg.com/2019/kyalami-drift

Gravityloss 5y ago
Of course that's not a turn. It's not a pure roll either. It's a massive sideslip that would be a very bad thing in a passenger airplane. For one, it reduces the speed a lot because the plane is flying somewhat sideways. Probably also aerodynamic loads would be massive. The tail fell off an A300 some years ago because the rudder had been used with too much gusto. This aerobatic plane can compensate with its oversized engine. Sideslipping is used to reduce speed in planes with no air speed brakes. Useful if you're coming in for a landing and are too high. This also wouldn't help in a cloud in any case - if the plane started turning from this position, you would be just as lost as in the other cases - the acceleration vector wouldn't change direction.
- nixpulvis 5y ago
  It could be a turn, just pull up and to the right and add a bit more gas and it'll veer off to the right no? Perhaps your definition of turn is one which preserves the directions of the down force? This solves the problem by definition, but doesn't address my comment. The article made me think that there was a physical law being obeyed here, when in reality it's more of a natural inclination to remain neutral. A level in an airplane will move around, even without performing such an intense maneuver, as hinted at the end of this article with the pendulums.
  - Gravityloss 5y ago
    You're confusing multiple phenomena. The way you traditionally turn an airplane is aerodynamically efficient, because there is no sideslip and the wing does all the heavy work of additional lift. If you just used your rudder to turn, while keeping the wings level, it would lead to a few issues. But yes, you can do this in an aerobatic plane. Usually you also have to use the ailerons to keep the wings level. Like said, this is sideslipping and is used to reduce speed in light planes. However that doesn't solve the cloud problem. Since the plane that can sideslip plane can also do coordinated turns where the force vector points to the floor, if you're in a cloud and the plane starts making a coordinated turn, you have no way of knowing. That the plane is able to make sideslips (with a lot of active steering) like in your video, doesn't help you. Here's a nice video showing a barrel roll in a multi engine plane with the a glass of iced tea on the dashboard: https://www.youtube.com/watch?v=W2-9BL7sllk https://www.youtube.com/watch?v=W2-9BL7sllk The pendulum mentioned works like a gyro - it is a dynamic system. This was explained in the article. It's the case precisely where a level does not work. Your inner ear doesn't work either. And this was discovered after a lot of people died and some survived near death. This is counterintuitive and was the whole point of the article.
    - nixpulvis 5y ago
      > Here's a nice video showing a barrel roll in a multi engine plane with the a glass of iced tea on the dashboard Unless I'm very confused (always possible) this is only because while inverted the airplane is losing a lot of altitude. If you want to fly upside down at a steady altitude, I'd assume you would need to be strapped in. Maybe ask Maverick ;) The cloud problem is the "natural inclination to remain neutral" I was referring to, where neutral is referring to the perceived G vector. If the plane can drift into a roll without changing the "feel" I see how you can end up in trouble. But that doesn't mean that all turns must preserve the G vector too. That was my only point.
      - Gravityloss 5y ago
        Yes, if you're inverted but the force vector points towards the plane floor, that means the plane is accelerating towards the ground (for example if it's flying a loop). And if you just fly straight and upside down, of course the force vector will point to the roof, not the floor. The problem was the plane making an unintended coordinated turn, which happens in the cloud. The nature of the turn is such that a human or a level can't detect it.

Gravityloss 5y ago

Of course that's not a turn. It's not a pure roll either. It's a massive sideslip that would be a very bad thing in a passenger airplane. For one, it reduces the speed a lot because the plane is flying somewhat sideways. Probably also aerodynamic loads would be massive. The tail fell off an A300 some years ago because the rudder had been used with too much gusto. This aerobatic plane can compensate with its oversized engine. Sideslipping is used to reduce speed in planes with no air speed brakes. Useful if you're coming in for a landing and are too high. This also wouldn't help in a cloud in any case - if the plane started turning from this position, you would be just as lost as in the other cases - the acceleration vector wouldn't change direction.

nixpulvis 5y ago
It could be a turn, just pull up and to the right and add a bit more gas and it'll veer off to the right no? Perhaps your definition of turn is one which preserves the directions of the down force? This solves the problem by definition, but doesn't address my comment. The article made me think that there was a physical law being obeyed here, when in reality it's more of a natural inclination to remain neutral. A level in an airplane will move around, even without performing such an intense maneuver, as hinted at the end of this article with the pendulums.
- Gravityloss 5y ago
  You're confusing multiple phenomena. The way you traditionally turn an airplane is aerodynamically efficient, because there is no sideslip and the wing does all the heavy work of additional lift. If you just used your rudder to turn, while keeping the wings level, it would lead to a few issues. But yes, you can do this in an aerobatic plane. Usually you also have to use the ailerons to keep the wings level. Like said, this is sideslipping and is used to reduce speed in light planes. However that doesn't solve the cloud problem. Since the plane that can sideslip plane can also do coordinated turns where the force vector points to the floor, if you're in a cloud and the plane starts making a coordinated turn, you have no way of knowing. That the plane is able to make sideslips (with a lot of active steering) like in your video, doesn't help you. Here's a nice video showing a barrel roll in a multi engine plane with the a glass of iced tea on the dashboard: https://www.youtube.com/watch?v=W2-9BL7sllk https://www.youtube.com/watch?v=W2-9BL7sllk The pendulum mentioned works like a gyro - it is a dynamic system. This was explained in the article. It's the case precisely where a level does not work. Your inner ear doesn't work either. And this was discovered after a lot of people died and some survived near death. This is counterintuitive and was the whole point of the article.
  - nixpulvis 5y ago
    > Here's a nice video showing a barrel roll in a multi engine plane with the a glass of iced tea on the dashboard Unless I'm very confused (always possible) this is only because while inverted the airplane is losing a lot of altitude. If you want to fly upside down at a steady altitude, I'd assume you would need to be strapped in. Maybe ask Maverick ;) The cloud problem is the "natural inclination to remain neutral" I was referring to, where neutral is referring to the perceived G vector. If the plane can drift into a roll without changing the "feel" I see how you can end up in trouble. But that doesn't mean that all turns must preserve the G vector too. That was my only point.
    - Gravityloss 5y ago
      Yes, if you're inverted but the force vector points towards the plane floor, that means the plane is accelerating towards the ground (for example if it's flying a loop). And if you just fly straight and upside down, of course the force vector will point to the roof, not the floor. The problem was the plane making an unintended coordinated turn, which happens in the cloud. The nature of the turn is such that a human or a level can't detect it.