Building a semi human powered flying device

[Jarno]

About the wingspan.
Let’s say the total weight would be 100kg (pilot 85kg + wingconstruction 15kg) I would need the following squared meters of wing surface, depending on my running speed:
10 km/h, 140m2
20 km/h, 35m2
30 km/h, 15m2
40 km/h, 9m2

If the weight would be reduced by let’s say 20kg and the total lifted weight would be 80kg you can proportionally reduce the wingspan: so with a running speed of 20km/h: 0,8 x 35 = 28m2

With a more efficient flapping movement the wingspan can also be reduced (and with a smaller surface I'll obviously reduce total weight).

according to DIY robotics, watch this:
roundedoff.com/2011/03/10/skeletonics-the-diy-exoskeleton-made-by-japanese-students-video/

 

[phlogistician]

About the wingspan.
Let’s say the total weight would be 100kg (pilot 85kg + wingconstruction 15kg) I would need the following squared meters of wing surface, depending on my running speed:
10 km/h, 140m2

Dude, mates of mine are kite surfers. They deploy 14m^2 kites to kite surf with sometimes. They are pretty frikking big, and they only have inflatable spines to keep their shape. A wing with 140m^2 surface area CANNOT be made rigid and weigh in at less than 15Kg.

Back to your drawing board. Actually, no, get out some more, and look around what is doable now, then get back to the drawing board.

also:

depending on my running speed

means diddly once you take off! You have to be able to maintain airspeed by flapping alone,....

 

[Daedelus]

Seems basic maths eludes you.

Jarno and I have some differences in our ideas but I believe they will converge eventually. Neither of us has claimed that a human could flap the size wing required. What we are proposing is an augmented system. The word haptics is applicable here if you are familiar with it.

 

[Daedelus]

... CANNOT be made ...

Pretty damn positive aren't you?

There are hang gliders that are that big, 28M2, which are used in tandem flying that carry loads of as much as 450#.

A kite surfing rig is a different animal. I do both.

daedelus.typepad.com/.a/6a0115702fe342970b014e8a99417a970d-800wi

 

[MacGyver1968]

Let's see...using the 20km/h number of 35m^2...(that 140m^2 is just too laughably large to work with) Each wing would need to be 4 feet wide by 46 feet long and weigh the same as a house cat. That's not even including the weight of the electric motors and batteries that will power the wings.(a single motorcycle battery weighs 6 pounds)...or the weight of some sort of tail assembly necessary to adjust pitch and keep the thing flying straight.

I won't even go into trying to run with 100 feet of wings strapped to your back, or how you would keep the wingtips from digging into the ground.

 

[Jarno]

A wing with 140m^2 surface area CANNOT be made rigid and weigh in at less than 15Kg.

phlogistician, thanks for your critical and sharp opinions.

140 m2 of wingsurface is needed when lifting with a speed of 10 km/h. Average running topspeed of adult human beings is around 35 km/h (except for top athletics like Usain Bolt which can achieve speeds around 45 km/h).

But let's assume I can achieve a topspeed around 30 km/h with the complete flying device rigged on my body. According to my previous posted calculation that would make the wingspan 15m2, or even smaller if the robotic expansion would add more efficiency to the flapping movements.

humanbirdwings.net

 

[phlogistician]

There are hang gliders that are that big, 28M2, which are used in tandem flying that carry loads of as much as 450#.

And how much do these hang gliders weigh? MORE than 15kgs, eh? And the size quoted was for 140m^2, not a mere 28m^2.

Please, be consistent with your numbers. You'll look dishonest else.

 

[phlogistician]

But let's assume I can achieve a topspeed around 30 km/h with the complete flying device rigged on my body. According to my previous posted calculation that would make the wingspan 15m2, or even smaller if the robotic expansion would add more efficiency to the flapping movements.

It doesn't matter one iota how fast you can run, because as soon as you take off, your source of propulsion is lost. All that matters is how much propulsion you can get from your wings.

That would also require you to carry your 15Kg of equipment. A single 12v car battery weighs about 15Kg. You think you can run carrying 15Kg of payload at 30km/h? BULL SHIT.

And that is without calculating leading edge drag from your wings! Adding leading edge drag it becomes TOTAL BULLSHIT.

 

[Daedelus]

And how much do these hang gliders weigh? MORE than 15kgs, eh? And the size quoted was for 140m^2, not a mere 28m^2.

Please, be consistent with your numbers. You'll look dishonest else.

Some of the tandem hang gliders can approach 45kg in weight. The only limit to the size of a hang glider is the fact that they are weight shift controlled and beyond the 28m^2 size, the pilot is unable to maintain good control. Add other control features and that is not a problem.

And had you read the post, the final size that Jarno suggested was 28m^2.

As for 'looking dishonest', I have to say that I am amazed that anyone in a 'science forum' would use phrases like 'CANNOT be done'. That sort of thinking belongs in a religion forum. Of course it can be done. The cost may be prohibitive. But that is not the issue. A more helpful discussion would be suggestions as to how it could be done.

A human mission to Mars is certainly possible from a science and engineering position. Politically and economically, it would be difficult. But to say out of hand that it CANNOT be done, well that's what the told the Wright Bros. too.

 

[MacGyver1968]

I have to say that I am amazed that anyone in a 'science forum' would use phrases like 'CANNOT be done'.

That's because not everything CAN be done. Try building a wing that's 10 feet wide and 150 feet long out of anything, and see if you can get it weigh less than 33 pounds.

A 12' X 100' sheet of 6 mil poly sheeting weighs 34 pounds by itself...and that's not even enough to cover one full side of the wing.

 

[Daedelus]

That's because not everything CAN be done. Try building a wing that's 10 feet wide and 150 feet long out of anything, and see if you can get it weigh less than 33 pounds.

A 12' X 100' sheet of 6 mil poly sheeting weighs 34 pounds by itself...and that's not even enough to cover one full side of the wing.

Straw man argument. No one is talking about a 150 foot wing.

 

[MacGyver1968]

Straw man argument. No one is talking about a 150 foot wing.

Phlog said it was impossible to build a rigid wing with 140 m^2 surface area that weights only 15kg or 33 pounds He's right.

A wing with 140m^2 surface area CANNOT be made rigid and weigh in at less than 15Kg.

140m^2 = ~1500 square feet...or 150 ft x 10 ft. 1200 square feet of 6 mil plastic sheeting weighs more than 15kg by itself.

 

[phlogistician]

Some of the tandem hang gliders can approach 45kg in weight.

So three times the weight allowance you have given for your entire rig, and that doesn't include propulsion, and only gives you 28m^2.

And had you read the post, the final size that Jarno suggested was 28m^2.

But that surface area is arrived at by a calculation from a running speed! ROFL! You aren't going to be able to run at 20km/h carrying 20kilos. Not that running matters, because as soon as you take off, you lose all propulsion, you do understand that right.

As for 'looking dishonest', I have to say that I am amazed that anyone in a 'science forum' would use phrases like 'CANNOT be done'.

Selective quoting makes you look stupid. I said a 140m^2 wing weighing 15kg cannot be done. You seem to understand that a 28m^2 hang glider weighs much more than the proposed 15-20Kg payload stated, yet you do not acknowledge this means your ideas are flawed.

Of course it can be done. The cost may be prohibitive.

You understand the word 'prohibit' means it can't be done, and you just contradicted yourself?

But that is not the issue. A more helpful discussion would be suggestions as to how it could be done.

Weighing just 15Kg? 20Kg? Dream on.

A human mission to Mars is certainly possible from a science and engineering position. Politically and economically, it would be difficult. But to say out of hand that it CANNOT be done,

Actually, I think you need to go do some reading about the stresses of manned missions, and the requirements for a manned mission to Mars, because we are a long way of proving it can be done. But that's another discussion. Oh, one we've had here already discussing the 9 month long minimum mission and the problems there are with that. Like, only ONE person has ever spent that much time in space, but they were in orbit, and got constantly resupplied. So no, it CANNOT be done at the moment.

well that's what the told the Wright Bros. too.

Who said that? Given the Wright Bros were fairly late to aviation, and others were already flying, who said they couldn't too?

 

[phlogistician]

Straw man argument. No one is talking about a 150 foot wing.

10 km/h, 140m2

you sure nobody is?

But even at the 28m^2 wing, you can't run at 20km/h carrying 20Kgs. And if you could, you'd stall as soon as your forward momentum ran out.

 

[Daedelus]

But even at the 28m^2 wing, you can't run at 20km/h carrying 20Kgs. And if you could, you'd stall as soon as your forward momentum ran out.

You 'clearly' don't know enough about the subject to be throwing assertions of can't do this or can't do that. You can and I have.

 

[phlogistician]

You 'clearly' don't know enough about the subject to be throwing assertions of can't do this or can't do that. You can and I have.

You think you can sprint at 20kph carrying a load of 20Kg?

Not that it matters, because that 20Kg figure is bogus anyway. I think one of my chain mail vests weighs about 20lbs, and I have run in that, but it's weight is evenly distributed over my chest, and does not require any balancing. It also doesn't add to aerodynamic drag.

 

[Daedelus]

Blah blah, blah

Selective quoting makes you look stupid.

Blah blah, blah

You understand the word 'prohibit' means it can't be done, and you just contradicted yourself?

Blah blah, blah

Right back atcha, Phlo

Prohibitive in an economic sense means there might not be enough money. Not that it can't be done. Are you a scientist or a bean counter?

 

[MacGyver1968]

I don't know so I don't assume that you and MacGyver are the same puppet.

Naww....I'm a lot better looking, and Phlog is a lot smarter.

Jarno came to this board asking for opinions of his "design"....Phlog and I are doing just that. We are trying to point out that he is majorly underestimating many factors of this design, including weight, complexity of design, power requirements, availability of technology, and the physical limitations of the human body.

 

[phlogistician]

I just found Jarno's R&D Video:

http://www.youtube.com/watch?v=8kmEUuai-tE

 

[Daedelus]

You think you can sprint at 20kph carrying a load of 20Kg?

Not that it matters, because that 20Kg figure is bogus anyway. I think one of my chain mail vests weighs about 20lbs, and I have run in that, but it's weight is evenly distributed over my chest, and does not require any balancing. It also doesn't add to aerodynamic drag.

I don't think it, I said I have done it. The one little piece that you miss is that a wing flies when there is sufficient airflow over it to produce lift. Foot launching a glider is a matter of moving the wing forward quickly enough to generate the lift needed to carry it's own weight. At that point it becomes easy to run at full speed. Of course to continue to fly, it helps if the ground falls away from you. A little time educating yourself seems in order.

But all this is irrelevant to the proposed machine. There are certainly challenges to bringing together the technologies that can make it happen. No one disputes that or else it would have been done already. As noted, many have tried. Also noted, those who went before did not have the benefit of today's science and engineering.

That's all we are saying.