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Man Supposedly Flies With Custom-Built Bird Wings

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Re: Man Supposedly Flies With Custom-Built Bird Wings

#121

Post by starpilot »

seanalltogether wrote: post #102
avree wrote: post #19

Incredibly skeptical. Red flags: 1. He's received criticism about his videos before, but still insists on filming in random parks, only releasing to press after the event, and using blurry/shaky footage. 2. When he takes off, the camera shakes heavily. When he lands, someone steps in front to block the view. 3. At 0:35, his legs lift up so that his body is parallel to the ground (necessary for flight.) If he had been…

Also, birds don't generate lift from merely flapping their wings up and down, they generate lift due to the angle of attack of the wing during the upstroke and downstroke. The wings in this video don't address this issue.

Depends on the bird and mode of flight. Large birds like condors basically glide like fixed-wing aircraft, flapping every few minutes; hummingbirds flap at 200 Hz and use various aerodynamic tricks to stay aloft. The flight in the video looks similar to the that of those toy flapping birds powered by a rubber band. It's possible to flap & fly without fully articulated twisting wings, just not as efficient.

Re: Man Supposedly Flies With Custom-Built Bird Wings

#123

Post by angersock »

narcoblix wrote: post #115
Lazare wrote: post #110

Watch a bird take off. Start with some pigeons, then some sea gulls. If you can, watch an albatross - on YouTube if nothing else. As you get larger, you get heavier; as you get heavier you need more lifting force (ie, bigger wings, moving faster). Recall that weight is a function of volume and increases with the cube of your dimensions, while lifting force is a function of surface area and only increases with the squ…

As someone has pointed out elsewhere, you can see in one of their other videos that they have major inconsistencies in the videos that they post. For instance, in this picture, http://i.imgur.com/3Fgct.jpg you can see that there is no black square above the "S" logo. Then, the camera points downward, then upward again, and there is a black square above the "S" logo. This video is very fake.

That's the most annoying inconsistency for me. I think that could be a patch to the wing applied after they managed to pull out the cloth from the spar (if you look at the blog a bit, there are some posts showing that issue). I think the shitty cut around 1:20ish could be them looking down during a screwed launch attempt, and splicing back in after adding the patch. You'll notice in the following video the patch is there from the start.

There is a Dutch news clipping from about a week after video 13 that shows the dude without the patch, which is puzzling. Again, easily explained as using an old photo from before 13, but still.

Re: Man Supposedly Flies With Custom-Built Bird Wings

#124

Post by chubot »

jQueryIsAwesome wrote: post #74
InclinedPlane wrote: post #51

I made this for a nested comment, I'll bring it up a level. Think this looks real? http://i.imgur.com/YtPMI.png The grass in the second one (suspected CGI) isn't even the same color or saturation level.

My biggest issue is with a piece of the machine that suddenly appears 2 seconds latter: http://i.imgur.com/xZCAu.jpg

That doesn't look off to me. There is a dark spot in the first frame -- it's just masked by the much larger shadow going across the whole wing.

It seems fake to me, but I have yet to be convinced there's CGI. If it were CGI, within 2-3 hours someone will post a statistical analysis of the images. That would be extremely obvious, whereas most people in this thread are pointing out things that are ambiguous.

I mean they if they got the trees, the shadows, and the grass right, then I have a hard time believing they forgot to remove a dot somewhere on the wing. Those aren't the kinds of mistakes you would expect if someone was trying to match CGI to real footage.

Re: Man Supposedly Flies With Custom-Built Bird Wings

#125

Post by rloads »

angersock wrote: post #114
Lazare wrote: post #110

Watch a bird take off. Start with some pigeons, then some sea gulls. If you can, watch an albatross - on YouTube if nothing else. As you get larger, you get heavier; as you get heavier you need more lifting force (ie, bigger wings, moving faster). Recall that weight is a function of volume and increases with the cube of your dimensions, while lifting force is a function of surface area and only increases with the squ…

For the record, he's budgeting around 17 m^2 surface area for wing and 100 kg for pilot ( http://www.humanbirdwings.net/about/working-on-the-wings/ ). That's about 5 kg/m^2 wing loading, well within range of something for a microlight( http://www.caa.co.uk/default.aspx?catid=1416&pagetype=90... ) if a bit heavy for an unpowered glider. EDIT: The wing surface (that kite he mentions sacrificing) is from one of these (…

Finally someone pulled out meaningful fact about flying. How funny people keep saying about video without taking into account any engineering or physical requirements to make this real.

Re: Man Supposedly Flies With Custom-Built Bird Wings

#126

Post by n8agrin »

JoeCortopassi wrote: post #34

Things that make this video implausible: 1) You have the engineering fortitude to come up with something that has never been done before, and you choose to attach it to your body with a consumer grade backback? And not even a full hiking one with multiple points of attachment? No rock-climbing harness? 2) Fabric is waaay too loose on the wings to be effective in any kind of aerodynamic sense. At best this is a kite 3…

It is a kite, made by Slingshot. See: http://i.imgur.com/3Fgct.jpg and http://ride.slingshotsports.com/kiteboarding/leading-edge-in...

Re: Man Supposedly Flies With Custom-Built Bird Wings

#127

Post by gregable »

Agreed with others that it's probably fake, but there I disagree that it's impossible. One of the slightly counter-intuitive things you learn when becoming a pilot is that you take off into the wind rather than with a tailwind. The wings don't care what your ground speed is when creating lift, they care about your airspeed. Given a big enough "kite" and a nice headwind and of course you can do this. Kitesurfers, kiteboarders, and hangliders do this all the time. The flapping may or may not assist, but it's certainly not doing the brunt of the work.

Re: Man Supposedly Flies With Custom-Built Bird Wings

#128

Post by angersock »

rloads wrote: post #125
angersock wrote: post #114

Earlier quoted context omitted.

For the record, he's budgeting around 17 m^2 surface area for wing and 100 kg for pilot ( http://www.humanbirdwings.net/about/working-on-the-wings/ ). That's about 5 kg/m^2 wing loading, well within range of something for a microlight( http://www.caa.co.uk/default.aspx?catid=1416&pagetype=90... ) if a bit heavy for an unpowered glider. EDIT: The wing surface (that kite he mentions sacrificing) is from one of these (…

Finally someone pulled out meaningful fact about flying. How funny people keep saying about video without taking into account any engineering or physical requirements to make this real.

Annoying as hell, isn't it?

>:(

More usefully, I don't mind if this turns out to be a fake--but this off-the-cuff "no it is not possible ever" is so narrowminded when not combined with credible facts and analysis.

Re: Man Supposedly Flies With Custom-Built Bird Wings

#129

Post by seanalltogether »

starpilot wrote: post #121
seanalltogether wrote: post #102

Earlier quoted context omitted.

Also, birds don't generate lift from merely flapping their wings up and down, they generate lift due to the angle of attack of the wing during the upstroke and downstroke. The wings in this video don't address this issue.

Depends on the bird and mode of flight. Large birds like condors basically glide like fixed-wing aircraft, flapping every few minutes ; hummingbirds flap at 200 Hz and use various aerodynamic tricks to stay aloft. The flight in the video looks similar to the that of those toy flapping birds powered by a rubber band. It's possible to flap & fly without fully articulated twisting wings, just not as efficient.

True, however those toy birds generate forward thrust and rely on the tail to move upwards or downwards since they're so simplistic. There is no tail on the device in the video, so there's no mechanism driving it upward.
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