4 ms·

Air moves and the plane will move with it, subject to inertia. Think of the air like water. (Air has fluid dynamics.)If the water suddenly drops away from a bo

Air moves and the plane will move with it, subject to inertia. Think of the air like water. (Air has fluid dynamics.)If the water suddenly drops away from a boat, the boat isn’t going to magically hover above the water.

darkwater 2y ago
Obviously, but then the boat and all the objects within it would be experiencing the same gravity acceleration, immediately, at the same time.
- deleted 2y ago
  [deleted]
- xenadu02 2y ago
  > Obviously, but then the boat and all the objects within it would be experiencing the same gravity acceleration, immediately, at the same time. That is not correct. The airplane experiences this uniformly because the wings transmit the forces to the fuselage. But the contents of the aircraft follow Sir Issac Newton and want to continue their previous motion. If the aircraft experiences high enough negative G then anything not strapped down will appear to rise relative to the fuselage. To put it another way: you need a physical connection (eg seatbelt or cargo strap) to transmit the force in such an event, just as the fuselage needs a connection to the wings to transmit the force.
  - istjohn 2y ago
    OP was commenting on the analogy of a boat that has the water underneath it suddenly drop away.
  - darkwater 2y ago
    Still not convinced. The plane is both carrying you tangentially to the Earth surface (to simplify) and sustaining you against gravity. If a turbulence just makes disappear the sustain against gravity, the wings, the fuselage and everything inside will start free-falling at the same time, effectively being a reduced gravity system. This is what happens in the ISS and there is actually a NASA aircraft (Vomit Comet [1]) that does that on purpose. OTOH if the aircraft suddenly goes down faster than 1G, let's say 2G, and you are not tied to anything, you will experience a 1G acceleration towards the roof, because you are "just" falling at 1G. [1] https://en.wikipedia.org/wiki/Reduced-gravity_aircraft https://en.wikipedia.org/wiki/Reduced-gravity_aircraft
    - xenadu02 2y ago
      We covered this in the other thread but to give a simple summary: It is not purely a reduction in lift causing the aircraft to begin free falling. Different air masses can move in different directions, including downwards or in a circular motion. When the velocity of the air is high enough it can easily push the airplane down faster than free-fall otherwise would.

darkwater 2y ago

Obviously, but then the boat and all the objects within it would be experiencing the same gravity acceleration, immediately, at the same time.

deleted 2y ago
[deleted]
xenadu02 2y ago
> Obviously, but then the boat and all the objects within it would be experiencing the same gravity acceleration, immediately, at the same time. That is not correct. The airplane experiences this uniformly because the wings transmit the forces to the fuselage. But the contents of the aircraft follow Sir Issac Newton and want to continue their previous motion. If the aircraft experiences high enough negative G then anything not strapped down will appear to rise relative to the fuselage. To put it another way: you need a physical connection (eg seatbelt or cargo strap) to transmit the force in such an event, just as the fuselage needs a connection to the wings to transmit the force.
- istjohn 2y ago
  OP was commenting on the analogy of a boat that has the water underneath it suddenly drop away.
- darkwater 2y ago
  Still not convinced. The plane is both carrying you tangentially to the Earth surface (to simplify) and sustaining you against gravity. If a turbulence just makes disappear the sustain against gravity, the wings, the fuselage and everything inside will start free-falling at the same time, effectively being a reduced gravity system. This is what happens in the ISS and there is actually a NASA aircraft (Vomit Comet [1]) that does that on purpose. OTOH if the aircraft suddenly goes down faster than 1G, let's say 2G, and you are not tied to anything, you will experience a 1G acceleration towards the roof, because you are "just" falling at 1G. [1] https://en.wikipedia.org/wiki/Reduced-gravity_aircraft https://en.wikipedia.org/wiki/Reduced-gravity_aircraft
  - xenadu02 2y ago
    We covered this in the other thread but to give a simple summary: It is not purely a reduction in lift causing the aircraft to begin free falling. Different air masses can move in different directions, including downwards or in a circular motion. When the velocity of the air is high enough it can easily push the airplane down faster than free-fall otherwise would.