5 ms·

Quote from the text: "Mr Browning said it is easily capable of flying at 200mph (321km/h) and an altitude of a few thousand feet. But, for safety reasons, he

by Fradow 9y ago

Quote from the text: "Mr Browning said it is easily capable of flying at 200mph (321km/h) and an altitude of a few thousand feet. But, for safety reasons, he keeps the altitude and speed low."

mikejb 9y ago
"Safety" - he's technically correct, but I believe it is guaranteed death if he'd try it: "The suit can currently fly uninterrupted for around 10 minutes." That leads me to the assumption that if he climbs up to a few thousand feet or goes full throttle to reach that speed, he'll be out of fuel faster than he can break & land.
- the8472 9y ago
  adding a parachute might help, at least once he's high enough.
  - rsl7 9y ago
    Sounds like the next extreme sport. rocket up.. wingsuit/parachute down.
    - chinathrow 9y ago
      Yves "Jetman" Rossy does that on the way down. Up with a helo, flying with a wing, propulsion jet engines. https://www.youtube.com/watch?v=pNaZCDhvh88 https://www.youtube.com/watch?v=pNaZCDhvh88
joncrocks 9y ago
I can jump over buildings with a single bound. But for safety reasons I only jump a foot or so off the ground. :-)
- darkerside 9y ago
  s/over/off ;)
SideburnsOfDoom 9y ago
> "it is easily capable of an altitude of a few thousand feet. But, for safety reasons, he keeps the altitude and speed low." Sure. I have watched some of the video, and at no point does he sustain a height high enough to stop benefiting from ground effect. Hovering for maybe 10 seconds at 5 meters up would do it. Until he does demonstrate this, I shall choose not to believe him, and won't consider this actual "flight". For much the same reason that an Ekranoplan is not actually an aircraft. See also: https://en.wikipedia.org/wiki/Ground_effect_(aerodynamics) https://en.wikipedia.org/wiki/Ground_effect_(aerodynamics) or comments last time this device was on hacker news: https://news.ycombinator.com/item?id=13993728 https://news.ycombinator.com/item?id=13993728
- mannykannot 9y ago
  Does ground effect apply, when your lift is from a narrow jet rather than a wing? I believe ground proximity presents a problem for VTOL jets, at least in part due to recirculation.
- upofadown 9y ago
  To get ground effect with something like that you would have to interrupt any recirculation (see helicopter ground effect). Just looking at the dimensions of everything you would think that the possible ground effect (recirculation) zone would be less than half a metre and the engines are higher off the ground than than that.
- Robotbeat 9y ago
  Ground effect in this case would be virtually non-existent because of the extremely small disk loading in the case of those miniature jet engines. The ratio of the jet diameter to each jet's height off the ground shows that the ground effect is pretty small in this case. Probably less than 1 percent thrust increase in the case where the jets are attached to his arms and back according to this graph: http://www.copters.com/aero/pictures/Fig_2-39.gif http://www.copters.com/aero/pictures/Fig_2-39.gif (This graph proves that he's getting essentially zero ground effect.) The actual exhaust velocity of those jets is extremely high, and for a lot of the video he is holding the jets at a significant angle with respect to vertical, giving cosine losses. With a thrust to weight ratio of over 1, I have no doubt he could achieve extremely high speeds (yeah, 200mph or over) given even a slight amount of lift from his body in horizontal(ish) flight.
fareesh 9y ago
Hard to believe he couldn't find a height between 3 feet and a few thousand to do a safe demonstration
atroll 9y ago
that cant be possible

by Fradow 9y ago

Quote from the text: "Mr Browning said it is easily capable of flying at 200mph (321km/h) and an altitude of a few thousand feet. But, for safety reasons, he keeps the altitude and speed low."

mikejb 9y ago

"Safety" - he's technically correct, but I believe it is guaranteed death if he'd try it: "The suit can currently fly uninterrupted for around 10 minutes." That leads me to the assumption that if he climbs up to a few thousand feet or goes full throttle to reach that speed, he'll be out of fuel faster than he can break & land.

the8472 9y ago
adding a parachute might help, at least once he's high enough.
- rsl7 9y ago
  Sounds like the next extreme sport. rocket up.. wingsuit/parachute down.
  - chinathrow 9y ago
    Yves "Jetman" Rossy does that on the way down. Up with a helo, flying with a wing, propulsion jet engines. https://www.youtube.com/watch?v=pNaZCDhvh88 https://www.youtube.com/watch?v=pNaZCDhvh88

joncrocks 9y ago

I can jump over buildings with a single bound. But for safety reasons I only jump a foot or so off the ground. :-)

darkerside 9y ago
s/over/off ;)

SideburnsOfDoom 9y ago

> "it is easily capable of an altitude of a few thousand feet. But, for safety reasons, he keeps the altitude and speed low." Sure. I have watched some of the video, and at no point does he sustain a height high enough to stop benefiting from ground effect. Hovering for maybe 10 seconds at 5 meters up would do it. Until he does demonstrate this, I shall choose not to believe him, and won't consider this actual "flight". For much the same reason that an Ekranoplan is not actually an aircraft. See also: https://en.wikipedia.org/wiki/Ground_effect_(aerodynamics) https://en.wikipedia.org/wiki/Ground_effect_(aerodynamics) or comments last time this device was on hacker news: https://news.ycombinator.com/item?id=13993728 https://news.ycombinator.com/item?id=13993728

mannykannot 9y ago
Does ground effect apply, when your lift is from a narrow jet rather than a wing? I believe ground proximity presents a problem for VTOL jets, at least in part due to recirculation.
upofadown 9y ago
To get ground effect with something like that you would have to interrupt any recirculation (see helicopter ground effect). Just looking at the dimensions of everything you would think that the possible ground effect (recirculation) zone would be less than half a metre and the engines are higher off the ground than than that.
Robotbeat 9y ago
Ground effect in this case would be virtually non-existent because of the extremely small disk loading in the case of those miniature jet engines. The ratio of the jet diameter to each jet's height off the ground shows that the ground effect is pretty small in this case. Probably less than 1 percent thrust increase in the case where the jets are attached to his arms and back according to this graph: http://www.copters.com/aero/pictures/Fig_2-39.gif http://www.copters.com/aero/pictures/Fig_2-39.gif (This graph proves that he's getting essentially zero ground effect.) The actual exhaust velocity of those jets is extremely high, and for a lot of the video he is holding the jets at a significant angle with respect to vertical, giving cosine losses. With a thrust to weight ratio of over 1, I have no doubt he could achieve extremely high speeds (yeah, 200mph or over) given even a slight amount of lift from his body in horizontal(ish) flight.

fareesh 9y ago

Hard to believe he couldn't find a height between 3 feet and a few thousand to do a safe demonstration

atroll 9y ago

that cant be possible