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Flyboard Air Test

  • Category: Video  |
  • 12 Apr, 2016  |
  • Views: 2602  |
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№1 Author: workmanboss (12 Apr 2016 04:43) Total user comments: 32


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Why did'nt that landing look real 02
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№2 Author: OldOllie (12 Apr 2016 08:48) Total user comments: 1673


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All in all, a pretty damned good fake.
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№3 Author: Nick1090 (12 Apr 2016 09:04) Total user comments: 1257


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Did a little research trying to see if it was fake, couldn't find a definitive answer, but did find this:

There are a bunch of miniature jet engines on the market typically used in RC jets that produce up to around 80 pounds of thrust, so if you had 4 of them on the bottom of that thing (which is what it seems if you pause the shot from underneath towards the end), that's 320 lbs of thrust that could be used to life him off the ground.

Say he weighs 200lb, the mini jet engines I mentioned weigh about 8 lbs a piece, and lets add another 20 lbs for the housing and electronics (the weight of a small bicycle) so thats a total weight of 252 pounds.


Using F=ma, with a net force of 68lbs which is 302.479 Newtons, and a mass of 252lbs which is 114.305kg, acceleration comes out at 2.65 meters/second squared.

Target speed is 93mph, which is 41.575 meters/sec. So at our calculated acceleration if we use a = dv/dt and solve for dt, it would only take 41.575/2.65 = 15.689 seconds to reach 93mph.

So now the only calculation left is for the ceiling - 10K feet is 1.89 miles, and traveling upward at 93mph you'd crack that ceiling in just 1.2 minutes.

Now clearly I've left out things that will also need to be considered (weight of the fuel, air resistance, percentage of thrust being vectored off to keep the craft stable and moving in the desired direction, etc), but none of that is significant enough to make this unfeasible. So I'd have to say that based on rough calculations it is certainly possible that this thing can do just what they say it does. With that said, it has been a very long time since physics class, so grateful if I have overlooked or messed up something major enough to torpedo my calculations.
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№4 Author: kryptor (12 Apr 2016 10:32) Total user comments: 4827


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I want to believe ...
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№5 Author: Nem0 (12 Apr 2016 17:31) Total user comments: 74


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Quote: Nick1090
Did a little research trying to see if it was fake, couldn't find a definitive answer, but did find this:

There are a bunch of miniature jet engines on the market typically used in RC jets that produce up to around 80 pounds of thrust, so if you had 4 of them on the bottom of that thing (which is what it seems if you pause the shot from underneath towards the end), that's 320 lbs of thrust that could be used to life him off the ground.

Say he weighs 200lb, the mini jet engines I mentioned weigh about 8 lbs a piece, and lets add another 20 lbs for the housing and electronics (the weight of a small bicycle) so thats a total weight of 252 pounds.


Using F=ma, with a net force of 68lbs which is 302.479 Newtons, and a mass of 252lbs which is 114.305kg, acceleration comes out at 2.65 meters/second squared.

Target speed is 93mph, which is 41.575 meters/sec. So at our calculated acceleration if we use a = dv/dt and solve for dt, it would only take 41.575/2.65 = 15.689 seconds to reach 93mph.

So now the only calculation left is for the ceiling - 10K feet is 1.89 miles, and traveling upward at 93mph you'd crack that ceiling in just 1.2 minutes.

Now clearly I've left out things that will also need to be considered (weight of the fuel, air resistance, percentage of thrust being vectored off to keep the craft stable and moving in the desired direction, etc), but none of that is significant enough to make this unfeasible. So I'd have to say that based on rough calculations it is certainly possible that this thing can do just what they say it does. With that said, it has been a very long time since physics class, so grateful if I have overlooked or messed up something major enough to torpedo my calculations.

I'm probably mistaken here but don't jet engines need air constantly funneled through in order to work optimally? While moving that would be possible but while hovering I wonder how the engines would get enough air to maintain thrust.
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№6 Author: rostit (12 Apr 2016 20:17) Total user comments: 465


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Quote: Nem0
Quote: Nick1090
Did a little research trying to see if it was fake, couldn't find a definitive answer, but did find this:

There are a bunch of miniature jet engines on the market typically used in RC jets that produce up to around 80 pounds of thrust, so if you had 4 of them on the bottom of that thing (which is what it seems if you pause the shot from underneath towards the end), that's 320 lbs of thrust that could be used to life him off the ground.

Say he weighs 200lb, the mini jet engines I mentioned weigh about 8 lbs a piece, and lets add another 20 lbs for the housing and electronics (the weight of a small bicycle) so thats a total weight of 252 pounds.


Using F=ma, with a net force of 68lbs which is 302.479 Newtons, and a mass of 252lbs which is 114.305kg, acceleration comes out at 2.65 meters/second squared.

Target speed is 93mph, which is 41.575 meters/sec. So at our calculated acceleration if we use a = dv/dt and solve for dt, it would only take 41.575/2.65 = 15.689 seconds to reach 93mph.

So now the only calculation left is for the ceiling - 10K feet is 1.89 miles, and traveling upward at 93mph you'd crack that ceiling in just 1.2 minutes.

Now clearly I've left out things that will also need to be considered (weight of the fuel, air resistance, percentage of thrust being vectored off to keep the craft stable and moving in the desired direction, etc), but none of that is significant enough to make this unfeasible. So I'd have to say that based on rough calculations it is certainly possible that this thing can do just what they say it does. With that said, it has been a very long time since physics class, so grateful if I have overlooked or messed up something major enough to torpedo my calculations.

I'm probably mistaken here but don't jet engines need air constantly funneled through in order to work optimally? While moving that would be possible but while hovering I wonder how the engines would get enough air to maintain thrust.


No, not exactly. Turbines create a low pressure at the inlet by pushing high pressure out the back. That low pressure on the front causes air to funnel right in. No forward momentum needed. Its not like they scoop up air or suck air. Air will always move from high pressure to low pressure. So when the turbine runs and lowers the air pressure at the inlet, air naturally flows in. If you lookup AgentJayZ on Youtube, he has amazing info on gas turbines.
https://www.youtube.com/user/AgentJayZ
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