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# New Jet Hoverboard Video

04/21/2016 10:44 AM

I thought you gents would like to see this, if not seen already.

jet hover board new

Would you like to have one in your garage? Want to paint the barn without a ladder?

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#1

### Re: New Jet Hover Board video

04/21/2016 11:40 AM

Looks fake. Color me skeptical.

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#2

### Re: New Jet Hover Board video

04/21/2016 11:59 AM

CGI is too sophisticated these days, can't tell the real from the BS, but heck, there are still morons that believe the moon landings were all fake. That is a hell of a lot of trouble to go to for nothing.

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#11

### Re: New Jet Hover Board video

04/21/2016 3:01 PM

A little math my be illustrative?

1 ft-lb/sec = power units, right? It converts to 0.001818182 HP (British definition). In other words, 550 ft-lb/sec equates to 1 HP. Here they claim a total of 4 each 250 HP jet engines, for a total of 1000 HP equivalent thrust (I presume), with minor auxiliary power for controls. To know the impulse value of these jet engines we have to know the exhaust velocity, and the mass flow rate of the four mass flow turbines.

Suppose the total supported weight to be 500 lbs. This means the system has an output of -g applied to the 500 lbs. -g is -32 ft/sec2. At hover, the dynamic equilibrium is zero. g exerted downward, and -g upward. At any rate, 500 lbs is equivalent of 226.8 Kg.

If the exhaust velocity is subsonic (as it appears to be), the most it could be 343 m/sec (almost equal to Mach 1).

Ft=mΔv and this is the impulse equation. Clearly, the impulse of a jet engine does relate well to shaft horsepower. I still have no idea of mass flow, and I know most jet engines run lean. If the backpack carries 20 L kerosine, and that is good for 10 mins, and kerosine were to weigh about 0.8 Kg/L, we have 0.027 Kg/sec fuel burn, probably comprising about 3% of mass flow, thus mass flow has to be in the approximate range of 0.888 Kg/sec = X mass flow.

I get X x 343 m/sec per second = Y Kg-m/sec2 as the force applied to prevent the rider from falling? 226.8*9.80 Kg-m/sec2 is that force, namely 2222.64 Kg-m/sec2. The engine can produce about 304.6 Kg-m/sec2.

I am sure I am missing something really basic in the physics of this (once again).

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#16

### Re: New Jet Hover Board video

04/21/2016 4:04 PM

Based on P2=T3/4ρA, 1000HP (all four lifting engines), at 745.7 kW full "power" cannot produce more than

1504.6 Kg-m/sec 2 thrust

while well over 2200 is required, unless the man and contraption weighs less than the 500 lb assumption I made.

Truly if man and machine amount to only 250 lb. then perhaps lift off is feasible.

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#3

### Re: New Jet Hover Board video

04/21/2016 12:41 PM

Total fake....

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#4

### Re: New Jet Hover Board video

04/21/2016 12:55 PM

That one yes. I am not too sure about the one I posted, since it was put up by The Engineer publication. Usually they actually have fact checkers on the story before they write it up.

The more I think about it, what kind of gyro effect would four parallel 250 HP jet engines have, along with two tilt-thrusting side jet engines. Does the operator have to lean perpendicular to the tilt (bank) he needs to produce a turn?

In other words, lean forward, tilt tight (bank right) and turn right?

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#5

### Re: New Jet Hover Board video

04/21/2016 1:16 PM

Who took this picture (from the video)?

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#6

### Re: New Jet Hover Board video

04/21/2016 1:34 PM

George? Mildred? I don't know, perhaps it is a selfie.

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#8

### Re: New Jet Hover Board video

04/21/2016 2:54 PM

Yeah, he's pretty good at pulling out his selfie stick from somewhere and holding it that steady while flying around in the sky!

It's like those silly "reality" shows where we're supposed to think they are out in the middle of nowhere. Who's shooting the video?

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#7

### Re: New Jet Hover Board video

04/21/2016 1:58 PM

Then there's this:

f'ing debunker f'ing blasts Franky Zapata

Now I have no idea what I believe. The whole harness is pretty doggone bogus, alright.

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#9

### Re: New Jet Hover Board video

04/21/2016 2:55 PM

This one is real... and pretty cool to boot....

http://azflyboardrentals.com/

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#18

### Re: New Jet Hover Board video

04/21/2016 4:44 PM

No problem there, ridin' a fire hose.

Since water is much more massive than air, it takes a lot less energy (less exhaust velocity) to generate a given thrust. And you are not carrying your power source, it's down on the boat.

F=d/dt (m*v)=m*dv/dt (Thrust)

P=d/dt (.5*m*v^2)=m*v*dv/dt=v*F (Power = Velocity x Thrust)

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#24

### Re: New Jet Hover Board video

04/22/2016 9:10 AM

Thanks for clearing up a bit of physics fog I was suffering from.

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#10

### Re: New Jet Hover Board video

04/21/2016 2:59 PM

I should have seen that strap! Ouch!

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#12

### Re: New Jet Hover Board video

04/21/2016 3:02 PM

Please help me out with math in my post prior to this one. I think I took a left turn at Physics 101.

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#13

### Re: New Jet Hover Board video

04/21/2016 3:33 PM
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#15

### Re: New Jet Hover Board video

04/21/2016 3:40 PM

That must be the light version of it! ROFLMAO! I still need a math check on earlier post.

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#17

### Re: New Jet Hover Board video

04/21/2016 4:29 PM

Yes I believe so....the platform Should be quite stable gyroscopically speaking, however matching the thrust characteristics of each engine may be a bit more challenging...Flying jet powered platforms are not new, they have always experienced stability problems though, and fuel capacity issues....

This is probably the coolest personal flying platform, with turbofan engine...The Williams X-jet...

https://en.wikipedia.org/wiki/Williams_X-Jet

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#19

### Re: New Jet Hover Board video

04/21/2016 5:13 PM
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#14

### Re: New Jet Hover Board video

04/21/2016 3:37 PM

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#22

### Re: New Jet Hover Board video

04/21/2016 9:29 PM

Indeed. It's not summer yet, so why are we seeing reruns?

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#20

### Re: New Jet Hover Board video

04/21/2016 7:33 PM

If this were operated via a vacuum device from above, it could be called a HooverboardTM.)

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#21

### Re: New Jet Hover Board video

04/21/2016 8:36 PM

Never really see him take off or actually come in and land, only highly edited cut and paste video. Have a feeling the ground blast doesn't look like fun.

They did do it right to eliminate as much as possible with landing on the open grid.

Don't think it would be on ground, sod or gravel.

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#23

### Re: New Jet Hoverboard Video

04/22/2016 4:04 AM

Keeping it inside the garage would be a bit of a challenge.

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