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Personal flying on a new level

Old 6th Nov 2016, 10:40
  #21 (permalink)  
 
Join Date: Nov 2016
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Originally Posted by onetrack View Post
It has 4 x 250HP turbo reactors for power - 1000HP, just to lift one person?? Seems like massive overkill to me, and the fuel consumption to produce that HP must be enormous. Doesn't look like an economic or viable product from any angle, to me.
However, I guess the U.S. military will be itching to immediately order 100,000 of them at $1M each, to ensure that they have enemy-jaw-dropping, cutting edge, troop-movement methods, ready to hand.
Where do you get the "It has 4 x 250HP turbo reactors for power - 1000HP, " data from?

It looks to me that 4x 50kgf thrust turbines would be sufficient, these units weigh about 7kg each, and cannot produce that much equivalent power. For sure, the fuel consumption is very high, leading to limited utility. But the real story is in the control system, and the fact that the cost of all the parts is really very low, sub $20k, and falling.
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Old 6th Nov 2016, 11:28
  #22 (permalink)  
 
Join Date: Apr 2007
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Also interesting is that in the shots that show the underside of the board, it clearly shows six, possibly seven outlets (four/five in a central group and one either side) expectedly four/five for vertical thrust and the outer two possibly for vectoring. One could easily presume that there are six turbines/motors. Definitely looks like the backpack is fuel as the pilot seems to do a fuel check by lifting the bag with his left hand on a couple of occasions.

Last edited by Evil Twin; 6th Nov 2016 at 11:38. Reason: Extras
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Old 6th Nov 2016, 11:36
  #23 (permalink)  
 
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I wonder what the FAA will make of it? If they ever do, that is!
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Old 6th Nov 2016, 11:40
  #24 (permalink)  
 
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Where do you get the "It has 4 x 250HP turbo reactors for power - 1000HP, " data from?
Right from the mouth of the inventor, in his interview, below ...

"Interviewer: Can you tell me more about how it works? How many engines are in there?

Franky: We have four engines inside, and the power is 250 horsepower each. It’s about 1,000 horsepower total."


Franky Zapata racing - jet-powered flying hoverboard interview

Some table-napkin rough calculations tells me a backpack full of Jet-A1 sure isn't going to keep 1000HP fired up, for too long!
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Old 6th Nov 2016, 12:30
  #25 (permalink)  
 
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Originally Posted by onetrack View Post
Right from the mouth of the inventor, in his interview, below ...

"Interviewer: Can you tell me more about how it works? How many engines are in there?

Franky: We have four engines inside, and the power is 250 horsepower each. It’s about 1,000 horsepower total."


Franky Zapata racing - jet-powered flying hoverboard interview

Some table-napkin rough calculations tells me a backpack full of Jet-A1 sure isn't going to keep 1000HP fired up, for too long!
Mmm, ok, could be right. It would be nice to get to the detail beyond the journalism. If this is in fact the equivalent power of these turbines, it is quite an impressive way to use kerosene. Yes, maybe around 1 or 2 kg/minute.

Anyway, on the other matter about Stability and Control, likely similar concept to
https://www.youtube.com/watch?v=w2itwFJCgFQ
from 2:55.
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Old 6th Nov 2016, 16:56
  #26 (permalink)  
 
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No way are those turbines 250 Hp I Think he muddled his units; They certainly look about 250N size ie 100Kg of lift for 4
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Old 6th Nov 2016, 17:09
  #27 (permalink)  
 
Join Date: Nov 2016
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Originally Posted by ionagh View Post
No way are those turbines 250 Hp I Think he muddled his units; They certainly look about 250N size ie 100Kg of lift for 4
Typically difficult to rate a turbojet in terms of power, but we could look at the fuel flow (energy) rate a momentum metric. In any case, we know it needs around 100kgf thrust, which can be easily obtained and installed, and we know this sort of control system, if not the mechanism (maybe it uses gimballed units) is easy to get.

The thing is, while this one has low fuel efficiency, but excellent power/weight and cost*mechanical*complexity/performance, there is an increasing number of new devices coming out which perform a similar role and with longer endurance, less noise, less jet velocity etc.
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Old 6th Nov 2016, 20:38
  #28 (permalink)  
 
Join Date: Sep 2016
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Originally Posted by onetrack View Post
It has 4 x 250HP turbo reactors for power - 1000HP, just to lift one person?? Seems like massive overkill to me, and the fuel consumption to produce that HP must be enormous. Doesn't look like an economic or viable product from any angle, to me.
However, I guess the U.S. military will be itching to immediately order 100,000 of them at $1M each, to ensure that they have enemy-jaw-dropping, cutting edge, troop-movement methods, ready to hand.
I guess the U.S. military will be itching to immediately order 100,000 of them at $1M each, to ensure that they have enemy-jaw-dropping, cutting edge, troop-movement methods, ready to hand.
They had the same as this a long time ago:
Williams X-Jet / WASP
https://en.wikipedia.org/wiki/Williams_X-Jet
https://www.youtube.com/watch?v=uXNNc_HFodI
https://www.youtube.com/watch?v=27HaGvHzbgQ

Empty weight: 401 pounds (182 kg) (182 kg)
Loaded weight: 550 lb (250 kg)
Max. takeoff weight: lb (kg)
Powerplant: 1 modified Williams F107 turbofan, 570 lbf (2.6 kN)

Performance Maximum speed: 60 mph (96 km/h)
Range: endurance of 30-45 minutes
Service ceiling: 10,000 ft (3,049 m)
Rate of climb: ft/min (m/s)
Wing loading: lb/ft (kg/m)
Thrust/weight: 1.11
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Old 6th Nov 2016, 21:38
  #29 (permalink)  
 
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Onetrack. You quote Zapata as saying the four "turboengines" (sic.) develop 400 bhp each. They appear little bigger than those used by RC flyers and those certainly don't develop anything like 400 bhp. 25 lbs thrust is typical, which, whatever way you try to convert lbs. thrust to bhp, is nowhere near 400 bhp. Might our noses be starting to detect a small furry rodent here?
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Old 7th Nov 2016, 08:57
  #30 (permalink)  
 
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Buster11 - No, the figure stated is 250HP each - not 400HP. I, too, am skeptical of even the 250HP figure, and I'm thinking the standard poor level of journalism has mistranslated the power ratings.
I cannot imagine where it would require 1000HP to levitate and accelerate a human body.
The Martin Jetpack propels the operator with a 2.0L V4 piston engine producing 200BHP, and appears to provide a similar level of performance to the Zapata Racing version, with its 4 "turboengines".
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