What happens if you fly a drone in a moving elevator?

Discussion in 'Hangar Talk' started by SixPapaCharlie, Jan 15, 2019.

  1. flyingcheesehead

    flyingcheesehead Touchdown! Greaser!

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    Gaah. I've tried six ways from Sunday to try to put what I'm trying to say in words, and I'm failing miserably. Saying "Forget the air" was an attempt to make it simple, but really gave the wrong impression too.

    It all makes perfect sense in my head. :rofl:
     
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  2. jheyen

    jheyen Pre-Flight

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    Looks like he’s using an inexpensive drone that has no proximity sensors so the drone is using some on board sensors to try and stay level.

    We have more expensive drones that use sensors and they would move with the elevator going up, but probably not going down as they have no sensors on the top.

    Mine are too expensive and too big to fit in an elevator so I won’t be posting a video of that.
     
  3. flyingron

    flyingron Touchdown! Greaser!

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    Eh? The floor and the ceiling of the elevator are (hopefully) fixed together. If it maintains the same proximity to the floor, it has the same with the ceiling even if it has no sensors on top.

    Might be real fun to fly one of these in and out of a Paternoster elevator.
     
  4. Ravioli

    Ravioli Final Approach PoA Supporter

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    We need our local drone expert to try it. @overdrive148 - take one of those commercial monsters over to an elevator and repeat the test!
     
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  5. EdFred

    EdFred Touchdown! Greaser! PoA Supporter

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    You must not be talking about the guy in The Action Lab video. He's got the credentials.
     
  6. Juliet Hotel

    Juliet Hotel Line Up and Wait PoA Supporter

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    Its shouldn't need sensors on top in that scenario. The ground sensors should be able to deal with up drafts just as easily as down drafts.
     
  7. Gerhardt

    Gerhardt En-Route

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    I hadn't even noticed. Welcome to PoA EdFred. There used to be a guy with a similar name, FredEd, kind of irreverent and kept the place interesting. He died or something though.
     
  8. mkosmo

    mkosmo Pattern Altitude PoA Supporter

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    It's tough to articulate. It'd be much easier to visualize. Anybody have an elevator we can smoke cigars in?

    The air is important, but it's not fixed relative to the elevator like it sounds like some folks here are expecting. Three things happen are going to happen: Air flows in, air flows out, and air moves around like fluids do with acceleration around them. As far as we're concerned, the air is moving in some direction, at some speed likely somewhere between zero and the speed of the car + the speed of the fan in the elevator.
     
  9. genna

    genna Line Up and Wait

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    You can use water to approximate this. Fill a tub with water, put a floating ball on it and then have a rectangular box around the ball as an "elevator" with some dye inside. Move the box horizontally to eliminate the lighter than water issue or use ping-pong ball filled with water. What you will see is the water inside the "elevator" will be pushed by and around the ball with only small force being transferred from the "elevator floor" to the ball to get it moving a lot slower than the "elevator". And this is a non-compressible water.

    on the way UP, the force of moving air from the props of the drone would help it a little as it gets into the ground effect of the elevator, but this is not enough for a relatively fast moving elevator.

    EDIT: This is basically an air piston(or an airgun) problem. If the piston is not sealed to the walls, the air just goes around it and piston(bb) is not moving
     
    Last edited: Jan 16, 2019
  10. Ghery

    Ghery Final Approach

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    You certainly come up with some "interesting" questions for your posts. :p
     
  11. Salty

    Salty En-Route PoA Supporter

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    It’s all about acceleration. When the elevator is accelerating, it’s moving the air with it, but the drone is only pushing enough air to be hovering, not enough to be climbing, so it appears to fall or rise as the case may be. It’s still hovering relative to the world. The drone would pop up a bit, when the elevator goes up, just as it would if a thermal hit it at the speed of the elevator; the drone won’t accelerate to the “thermals” speed instantly - but then it’s back to acceleration. In his video the drone is able to almost catch up because the elevator stops accelerating. In a taller building it would be able to hold the hover after the acceleration stops, and would go the other way when the elevator slows again.
     
  12. mkosmo

    mkosmo Pattern Altitude PoA Supporter

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    Fantastic idea. To make it even better (although it won't solve the friction issue), make it a neutral buoyancy ball.
     
  13. WBI Flyer

    WBI Flyer Pre-takeoff checklist

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    Fluid Dynamics at play^^ it's not just the motion of the elevator. - also, may have been said before, but any kind of gyro that senses rate of climb or fall to stabilize that little quad would doom it to the floor or ceiling - the air density changing in the elevator is an interesting thing (more dense at the elevation being accelerated AWAY from). - needs an 0-360 in that thing. ;)


    Witness as a co-reference:
     
    Last edited: Jan 16, 2019
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