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Anyone remember the old trick question about a plane sitting on a treadmill running at the same speed as the take off speed of the plane? The question was would the plane take off or sit still? It takes off of course, but a buddy of mine and I were talking about a similar idea the other day and I wanted to see what you guys think.
OK, you are in an EMPTY 747 commercial jet. You are the only passenger and are sitting in the middle of the plane. You have a Tiny Whoop in your bag and think how cool it would be to fly inside the plane. You get it out and start flying. The drone is hovering while the plane is sitting still on the runway waiting for approval to take off. While hovering the drone, the pilot gets clearance, powers up and takes off. You don't do anything but watch, leaving the drone in a hover.
OK, I'm no engineer or scientist and there may be those of you who know the correct answer based on physics and such, but the way I see it, there are three possible ways this could go. There may be more than three and I'd love to hear your thoughts in the comments to add more and let me know which one you think is the correct answer and why.
Theory 1 is that the drone is flying in a column of air that is pressurized and as the plane moves forward, the column of air also moves forward with it allowing the drone to stay in place as if nothing is happening.
Theory 2 is that as the plane the moves forward the air inside moves backwards in relation to the plane, but only slightly causing the hovering drone to move backwards in the plane, but shortly coming back to a hover in the plane as the air stabilizes with the planes movement.
Theory 3 says that as the plane moves forward, the drone remains in place relative to the ground and slams into the back of the plane.
OK, so this is a little tricky. I've flown inside a moving car before and I know that at speed, the air inside the car is moving at the same speed and you can fly the drone around like normal. This question isn't about flying in the plane when it's already moving though, it's about what happens when it goes from not moving to accelerating forward. I'm not sure what exactly would happen, but I personally think that Theory 2 is the most likely correct answer. I think the air inside moves forward more than the air outside the plane so the drone wouldn't act as if it were left in the same exact position over the ground and slam into the back of the plane. I also don't think that it would remain exactly in place relative to the plane. It would likely move backwards some, but I don't know how far, maybe 2-10ft. It's interesting to think about. So let's hear your thoughts guys, what do you think would happen? Anyone ever try this in real life? I'd love to see a video.
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momentum
The "drone" like any other mass (weight) will maintain its speed and heading/ direction unless there is a force acting on it.
Since the gas/ air in the plane is also traveling at the same speed as the plane itself (gasses have mass) the air resistance will be about the same as "on the ground" / flying indoors. So IF the plane flies at a EXACT CONSTANT SPEED AND HEADING the "Drone" will behave just as it would flying indoors. ANY VARIATION of the speed and heading and the "drone" will move to the opposite direction (plane goes down, drone goes up relative to the plane) This is because there is not the same force acting on the drone/mass as there is on the plane that caused the change in speed/direction. In practice since its very unlikely a plane flies at a exact constant speed / heading the "drone" will move around in the cabin indicating those deviations in the speed / heading. ![]() On a other note ; flying a drone near a airliner (inside is as close as you can get..) can cause mass hysteria and airport shutdowns. ![]() |
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one detail
Airliners in flight are not pressurized to sea level air pressure.
Apparently the pressure is as you where at 8000 feet. So the performance of the drone is the same as it would be flying at this air pressure/ altitude . Unless the drone is able to fly at 2438 meters high it will not be able to maintain altitude. Likely its under powered or has the wrong props so any attempt to fly would result in it falling to the floor or just not take off. ![]() |
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So you are saying the drone will slam into the back of the plane?
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Force is mass times acceleration
If you know the weight of the drone in kg and you know how much trust (force) the motor/ prop combination gives then you can calculate how much the drone can accelerate/ slow down.
http://zonalandeducation.com/mstm/ph...ghtyFEqMA.html Slowing down takes the same amount of force as going faster just the other way. This assumes a vacuum so the actual performance will be a bit less because of air resistance. So IF the change in speed is below of the drone maximum acceleration (or slowing down.. same thing ![]() If not it will slam in the floor/ wall ceiling with the speed of the change minus the amount of speed it tried to compensate with.. The speed of impact depends on the distance between where the drone was since that dictates the time it takes to reach the point of impact. ![]() |
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When you jump up in the air inside your 747 do you slam into the back wall?
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at takeoff yesQuote:
During climbing (at constant speed) it would hit the floor ; During landing (speed brakes deployed for example) it would move towards the front of the plane. What would be a great clip is when the plane would do a perfect axial roll at constant speed. The drone would appear to be rolling inside (relative to the plane) while in fact it isn't (absolute to earth) |
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dependsQuote:
Same as a ball on the floor of your car moves around while you are driving. |
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what forces (or lack thereoff) do
Have a look at this; the plane climbs and dives in such a way it cancels out gravity.
To do that it has to pull out of the dive and during that part of the flight the people/mass inside experience several times the force of gravity. Flying a drone during during those conditions would be interesting (anyone have contacts at NASA? ![]()
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I volunteer! I’ve always wanted to ride in that plane.
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