Half a croissant, on a plate, with a sign in front of it saying '50c'
h a l f b a k e r y
Funny peculiar.

idea: add, search, annotate, link, view, overview, recent, by name, random

meta: news, help, about, links, report a problem

account: browse anonymously, or get an account and write.



Man powered flapping flight

Ornithopter humanicus transportium.
  [vote for,

I believe that I have figured out a way to build a human powered aircraft which could be flown safely in a variety of weather conditions by any physically fit person. The craft should not only fly but be able to hover, fly in reverse and perhaps after the first few prototypes, allow the pilot to leave the aircraft tethered and hovering for short periods of time, (I’m thinking mainly for search and rescue purposes).
After studying other H.P.A. designs, I have concluded that pedaling is no where close to the maximum mechanical output a human can generate, so in this contraption the pilot will be held rigidly in a body harness doing crunches, (from fetal position to full extension) and controlling weight displacement with movements of his or her head via servo motors. The aircrafts' premise is based upon the flight characteristics of a dragonfly, with one set of wings creating constant lift while the other set ascend with minimal air resistance, if enough power can be directed to the wings it will be possible to hover.
The framework will need to be made of a very light composite material or maybe bamboo. The wings should copy as closely as possible, the membrane separations of a dragonfly, (you can't beat mother nature when it comes to design specs), the difference being that each "membrane" will be filled with helium, housed in a Mylar pocket, each pocket valved and separate in case of a puncture. With four helium filled wings and about a twenty foot wingspan (subject to much research), the weight of the aircraft itself could attain neutral buoyancy, so that the pilot is only tiring to lift his own weight while hovering.

The craft would come equipped with a version of a dead-mans stick where the machine would cycle into a glide and bank mode with the camber of all four wings creating lift if the pilot loses consciousness, or allow the pilot to rest or charge energy storage devices which could add extra thrust to the wings when needed. I don't relish the idea of being the first guy to jump off of a cliff with this thing so for testing purposes the machine would hang by it's tail from a cross bar, if the pilot can not generate enough lift to bring it up to level and hover then it's back to the drawing board.

There is a lot more to this idea, redundant safety features, several energy storage devices, the wing pivot mechanisms, landing and take off details, etc. but this is getting a bit long winded. This idea is not yet baked to my knowledge but I have found two other whacos working on the same type of design.

I came across a sketch I did when I had the idea. http://s68.photobuc...widget_action=album
[2 fries shy of a happy meal, Oct 04 2004, last modified Oct 09 2011]

I also found a drawing of the remote control prtotype I built and tried to get a patent on. http://s68.photobuc...rent%3Dscan0002.jpg
I was ( II ) this close. [2 fries shy of a happy meal, Oct 04 2004, last modified Oct 09 2011]

Richard Pearse http://www.ctie.mon...rgrave/pearse1.html
In case you were wondering. [Nick@Nite, Oct 21 2004]

Spring Wings http://patricktimon...en.com/catalog.html
Spring Wing design [JesusHChrist, Jan 09 2005]

Spiral Spring Wings http://patricktimon...ven.com/photo3.html
See bad drawing entitled Sprial Spring Wings [JesusHChrist, Jan 09 2005]

The remote control dragonfly hits the market. http://www.technolo...ch_remote_cont.html
Mine was WAY bigger. [2 fries shy of a happy meal, Mar 10 2007]

Human Powered Ornithopter from Japan http://web.kyoto-in.../kazuho/index-e.htm
[spiraliii, Mar 10 2007]

all I can say is wow http://www.humanbir...flying-like-a-bird/
[theircompetitor, Mar 20 2012]

rain on my parade http://www.avweb.co..._hoax_206362-1.html
[JesusHChrist, Mar 23 2012]

Batbot https://youtu.be/6Brs6lWBvSE
[JesusHChrist, Feb 01 2017]


       Wouldn't it get difficult trying to pilot the craft while doing crunches?
RayfordSteele, Oct 06 2002

       RayfordSteele, thanx for the input. I don't think that trying to pilot while doing crunches would be difficult, as the the tail of the machine would extend, contract, and swing from side to side for hang glider-like weight displacement. These four directional controls the pilot would engage by moving his or her head with varying pressure against control rods. The pilots wrists and ankles would be held rigidly so that other, more subtle controlls such as wing tilt, gear changes, and auxiliary control of secondary power take off units could be initiated simply by: depressing buttons with the fingers, joy sticks for the pilots thumbs and something similar to a motor cycles gearshift for the feet. Totaly relaxing the pilots hands would engage the deadmans stick glide mode letting the pilot rest his head against the controll bar without affecting the craft. I can't think of anything which would let the pilot feel the air currents around him better than trying to "steer" with his or her head, there would not be a faster interface with the machine than directly from the inner ear ballance centre, to movements of the head. Watch someone play one of those flight simulation games sometime and note the movements of their head when things get tense.   

       I know very little about piloting, or about how flighted members of the animal kingdom function... but I do recall just a little physics from school. Thus it behoves me to request some clarification of the astonishing assertion which follows in repro. ... "With four wings and about a twenty foot wingspan the weight of the aircraft should be reduced to near zero"

hang on, sorry, I'm being a smart-arse. Have just noticed these wings are filled with helium. However as a pedant, not a physicist, it would be nice if the sentence in question read something more like: "With four wings and about a twenty foot wingspan the Helium should offset the weight of the aircraft to near zero."

back as a physicist then, with near-zero weight, how do you have any control on it? The Helium is always going to act in the vertical plane (no pun intended), or more correctly, towards lower pressure air. The 'weight' of an aircraft in flight, if I am not mistaken, is the force used off the vertical in banking manouevres, as it is the displacement of air over the wings due to force downwards from the plane's weight that makes them work. (I am having difficulty expressing myself here..)
Basically, you are trying to human-propel an aircraft; fine. I don't know enough to argue, croissant or fishbone. But I think I'm right that by trying to fiddle with the weight of the thing, you are creating more problems than you solve.
lewisgirl, Oct 07 2002

       The following change might help:   

       "With four wings and about a twenty foot wingspan the weight of the aircraft should be reduced to near zero." => "With four wings and about a twenty foot wingspan the aircraft should become neutrally buoyant in air."   

       The figures seem reasonable so long as you're considering the aircraft without its pilot.
st3f, Oct 07 2002

       Or veni, vidi, Da Vinci.
FarmerJohn, Oct 07 2002

       Don't sneeze.
egbert, Oct 07 2002

       Hearsay [UB], unfortunately.
bristolz, Oct 07 2002

       Pearse was a secretive man, unfortunately. He also designed a precursor to Harrier jets - so one could take off and land in their own backyard. He ought to be the focus of a documentary.
thumbwax, Oct 07 2002

       /st3f/, Thanx, changes noted and made. /lewisgirl/, I also have a hard time translating the thoughts in my head onto paper, or monitor for that matter, so please bear with me. Iv'e given quite a bit of thought to how a weightless craft might react once it is off the ground. Would the machine actualy be able to find "traction", (can't think of a better word), and be able to propell itself forward or would the pilot just end up flapping madly and not go anywhere fast? I could very well be wrong about this but, with one set of wings ascending in direct proportion to the pair descending, the main body of the machine should'nt oscilate much verticaly if it were'nt for only one pair, the downward stroke, creating lift. By tilting the angle of attack of the downward stroke some of that air pressure will be forced towards the rear of the wing, generating forward momentum (I think). As to the shape (camber) of an aircrafts' wing generating lift due to lower air pressure above the wing than below, this is true but only of a wing which is moving forward fast enough to create the pressure difference. This machines' four wings will have a teardrop shape to help with lift while gliding, but with a hovering craft the camber will do little besides help cup the air on the downstroke. (I think)   

       Okay. It's hearsay. There. A little more. He didn't document it so it's all a matter of faith at this point.   

       I wouldn't characterize "failed to document work" as "lack of publicity."  However either is a valid reason for languishing in obscurity and is, ultimately, the fault of Pearse.  He made his nest and landed in it.   

       Pearse's work is amazing but, to me, it's for reasons other than his alleged first flight.   

       I think his best work is not as a precursor to the Harrier because he was working on the notion of bird-like landings (wings that could dramatically change their chord, aspect and size much as a bird does when flaring) well after the advent of the Harrier. That he was doing it without absurd thrust ratios is what is amazing.
bristolz, Oct 08 2002

       /Sophocrat/ I thought about a rowing action before I did the crunch, and your right it would produce a lot more torque but only during the row itself. For the length of time it takes to "put the oars back in the water" you would produce very little. I have tried to determine what movements would acheive a constant, sustainable force.   

       Oh . . . easy . . . it's the movements where you turn an ignition switch and push the starter. "Vroom" is (often) the sound it makes.
bristolz, Oct 08 2002

       [ prediction/rant ] These contraptions are going to be on the market within the next ten years. I'd put money on it with five to one odds, but my wife would string me up by the short and curlies.   

       Maybe that should be fornicopter? But there's really no need to start getting rude.   

       The buoyancy of the craft isn't an issue as to it's ability to move through the air. However I would suggest that a larger wing span is needed, with a pilot of 70Kg (about 155lb) the loading on the wing would be very high and therefore you'd be having too move at quite some speed!
scubadooper, May 11 2003

       I certainly hope to.   

       I like the filled with helium wings + bouyancy "would be the start of an idea"; And great flexability that is also very strong, and moulds to your own body in-parts - to give more control - wouldn't it?.   

       To use also the knowledge of grearing/ratios, make that perhaps a factor in a design theory.   

       Completley flexabile wings - using arms fitted correctly and moulding to your own parts of your limb.   

       I'll look at the idea of posting a renderd image of what my idea I can dream-up could look like as something i'd want to work towards at this time.   

       I'll comeback again to you soon I hope and try and follow up of past addnotes and anythind else added after this also. Phill.
Phill Malloch, May 21 2003

       2 Fries, I think 4 wings acting as closely as possible as extensions of the four limbs, and designed around mathematical cornucopias, so that the wings wrap around the limbs until enough crawl-style stroke motion unfurels them would allow a person's energy to be translated efficiently into the air. If the wings are shaped right and the material is really springy, this shouldn't be that hard to do, especially with what we can do with modern materials. I think the important thing is to think of what motion is most natural to a human body that uses all the muscels at their ability level and then design wings so that they tranlate this motion efficiently into the air. There wouldn't have to be any moving parts, the wings should effectively "smooth" a person into the air with their shape. The wing suit should be a siimple one piece foam suit made out of springy foam and most importantly it should be shaped really adaptively, so that every change in the shape of the suit occurs gradually -- so at the edges the suit would gradually fade off into extreemly sharp but flexible edges. (See link for bad drawings entitled "spring wings")
JesusHChrist, Jan 09 2005

       So, how did that patent work out for you, [2fries]?
MikeOxbig, Jan 18 2006

       Another thing to consider is that (I believe) insects control forward/backward, etc. motion with a rotational movement of their wings. I wonder if there is currently even a powered machinel that can do that? (Not saying at all that it can't be done - It'd be very interesting)   

       I must submit to the statement: //If this worked then it would have been Leonardo Da Vinci who first achieved powered flight,//   

       I saw a replica of Da Vinci's glider fly (on TV). Unless you mean the helicopter sketch, I believe whole heartedly that the replica & show was a faithful attempt at reproducing Da Vinci's concept.
Zimmy, Jan 18 2006

       Gliding doesn't officially count as flying, so sadly our good friend DaVinci wasn't the first in flight. The machine has to be able to make a controlled and powered flight for it to count, which is why the Wright brothers got it (Pearse doesn't count either, cause he never achieved real controlled flight).
MikeOxbig, Jan 19 2006

       [21], there already are several man-powered airplanes, most of which can take off normally like a regular plane.
MikeOxbig, Jan 20 2006

       [MikeOxbig] I hired a company called The Better Mousetrap Company to do the patent search; the only thing similar was an old patent for a blimp with four wings. The owner of this company contacted me a short time later telling me that he was in partnership with a manufacturing company in China and that he wanted to bring my idea to the table at an upcoming meeting and that there was a good possibility that they would want to run with it.
Weeks went by, then months. My phone calls and emails were not returned, and a short time later I read an article about m.e.m.s, one of which was a dragonfly shaped device with the patent belonging to the Naval Research Laboratories in the States. I pretty much gave up on the toy version when I saw that.

       [21 Quest] Hovering would be difficult.
What I had in mind was storing energy while gliding or during forward flight when the shape of the wings would help with lift.
I had envisioned a counter rotating dual flywheel system with the flywheels themselves being made from hollow tubing and therefore too light to be of much use at first. When gliding your energy output would be used to increase the spin of the flywheels while filling them with compressed air, this would add weight to the machine when forward momentum would help to keep it aloft. For a rapid ascent or a long hover time stored energy from the flywheels spin would augment human power. When that spin energy is depleted the compressed air would be used, this would decrease the workload on the human while at the same time be decreasing the weight of the craft.

       Aww, too bad.
MikeOxbig, Jan 23 2006

       Tell me about it.   

       Saw this yesterday. [link]   

       // He ought to be made the subject of a documentory// He was, made with the help of funding from the NZ Broadcasting Corporation. So that we can see more of New Zealand on air. and a right old load of cobblers it was was too They should have been ashamed to air it. An abysmal effort to a genuine visionary aviation pioneer.
Ah Supp, Oct 05 2011

       // He made his nest and landed in it.// He landed in a gorse hedge about a hundred yards away actually, after taking off from the top of a slope. He designed and built every part of the plane by himself even casting the engine and a unique propeller.
Ah Supp, Oct 05 2011

       As someone close to obtaining a set of wings from the Almighty, I hope to Christ they work. I'll keep you posted.
Ah Supp, Oct 05 2011

       see link
theircompetitor, Mar 20 2012


       I think I just or-nithop-gasmed.
Nope. No, I'm sure of it.
Pardon me, I've gotta go change my shorts now... right after I write a poignant letter to Santa.

       I think the fundamental flaw here is in assuming that abdominal crunches will give a higher power output than pedalling.   

       You might (though I doubt it, actually) be able to generate more force in a crunch than you could with your legs. On the other hand, a fit person can run or cycle for several hours; how long can you do crunches for?   

       In other words, [2fries], what's the evidence to support your initial premise?
MaxwellBuchanan, Mar 23 2012

       This argument was had a few months ago, during the Ekranoplan fiasco. Actually, I think it's in the annos of 'Pedal-Powered Ekranoplan', the post directly below this one.
Alterother, Mar 23 2012

       Ah. Time flies when one is having fun.
MaxwellBuchanan, Mar 23 2012

       There's no reason the argument should not resume; I merely pointed that out for reference purposes. By all means, please argue! I'll just stand over here...
Alterother, Mar 23 2012


       [8th], do you have a spare gauntlet I can borrow? I wish to throw it down in front of [2 fries] and challenge him to support his argument that abdominal crunches can give a higher sustained power output than legs.   

       (Which reminds me, I still owe [8th] a hat. Still, no point wearing a hat with only one gauntlet.)
MaxwellBuchanan, Mar 23 2012

       Pretty simple to test. Put athletes on rowing machines and pedal machines and measure the power. I suspect that the difference won't be large, but it's easier to operate at your aerobic limit when using more muscles. Which is why, for example, trained cyclists still use other forms of exercise, such as running (or, indeed, rowing machines), to increase their aerobic fitness.
spidermother, Mar 23 2012

       // Put athletes on rowing machines and pedal machines and measure the power. //   

       The number of variable factors in an experiment like that is mind-boggling, so it is fortunate for us that there are thousands of people around the world whose job it is to do just that and publish their findings. If only there were some medium by which we could gain access to the data they've compiled and analyzed...
Alterother, Mar 23 2012

       I can't believe someone would fake that video.
Leonardo just flipped him the bird from the grave I'm sure.
I want to find him and, and... I don't know what, but something really miffed.
What an asswipe! I went and forwarded that video to the Ornithopter society all giddy like a total schmuck.

       As for crunches being more powerful and sustainable than peddaling it seems a no-brainer to me [MB].
Peddaling involves the force of one leg depressing a lever while the other leg adds minimal force raising that same lever.
Crunches deliver the force of both legs pushing simultaneously with the addition of arm, upper torso, and abdominal muscles, and then again with that same combination in retraction.

       Put it this way, how many squats could you do in a row using only one leg?   

       How could crunches not be more powerful?
...and several times more powerful at that.

       //both legs pushing simultaneously// That makes no difference to the power the legs can deliver, though it might make mechanical sense in an ornithopter.   

       I seriously doubt that you could deliver several times the power. Roughly half the skeletal muscles are in the legs and buttocks. Also, as I implied above, the cardiavascular system imposes a limit for exertion lasting more than tens of seconds. At best, you could maybe double the power for short bursts. But again, it's very easy to test, and almost certainly has been (as [Alterother] kindly pointed out).
spidermother, Mar 24 2012

       Crunches aren't going to deliver all that much power. The back muscles are much stronger than the stomach muscles, and the legs are designed to push, not pull--the arms can do whatever. So a pull from a rowing position gets all the body's muscles working at their best, arms, back and legs.   

       Back when I was doing a lot of bicycling, there was a rule of thumb to tell whether you were running out of muscle or out of cardio. I recall it as your legs getting rubbery meant they failed, gasping for breath meant your cardio wasn't keeping up. The point being that as was said, you could develop a method that used every muscle in your body at once, and not be able to keep using them for more than a few seconds.   

       As for human powered flight, it simply is on the edge of what is possible. Flapping flight isn't all that efficient, unless done by a well-adapted bird. Separating lift and drive allows you to optimize each ... usually.   

       // (you can't beat mother nature when it comes to design specs) //   

       Actually, you often can--man-made vehicles are much more efficient than animals, energy-wise.   

       And filling a structure with helium is generally a waste of time. It's not all that "lifty", and it leaks like hell.   

       As for the flying Dutchman, I didn't believe it for a second.
baconbrain, Mar 24 2012

       Yes... I must work on my gullibility.
I think I was just pulling a Mulder and *wanted* to believe. Truth be told it makes me want to build this thing even more now.

       I think there are new graphene composites which have zero helium permeability. It makes sense to have inflated wing sections for strength lightness and shape, swapping the air for helium might bring the bouyancy of the craft itself to near neutral so that a pilot would only be lofting their own weight.   

       I am having a hard time finding stats on the physics of crunches, probably just not using the right words.
A fellow halfbaker I was discussing this idea with had fine suggestion as to maximizing force though.
As humans we are designed to carry our own weight and a bit more upright. Add 300 lbs and you probably won't be able to a squat and then stand with that much weight, but that same weight can be pushed easily with the legs, even against friction over and over again, if a person is sitting with their back braced against something immovable.
He was also right about it being much more comfortable to fly recumbant. Better for the lungs too.

       You might be right, but beware of confusing force, power and endurance. Leg muscles are built for prolonged exertion, and have the appropriate mix of fast and slow fibres, and also a blood supply that can keep them aerobic for long periods of time.   

       I'm not sure about the other major muscle groups, but they're not normally called upon for prolonged exertion. Therefore, I'm not convinced they'll hold up as well in the long term. I might be wrong, though. Don't forget also that if you exercise to build up muscle mass, and if some of those muscles aren't good at prolonged exertion, you've still got to carry them around.
MaxwellBuchanan, Mar 24 2012

       //Energy input required per second = mgh = 100Kg x 10 x 1 = 100 Joules//   

       Hang on - where did that mgh equation come from? It would be the equation for climbing at a rate of 1m/s up a staircase, and is probably something close to the requirements for hovering flight, but not necessarily the equation for sustaining height.   

       After all, consider a 100kg glider with a 20:1 glide ratio, travelling at 10m/s. To sustain level flight, all you'd need to do is to jack it up by 0.5m at intervals of 1 second, requiring an average energy input of only 50W.
MaxwellBuchanan, Mar 24 2012

       Fair enough.   

       Now that man-lifting electric helicopters exist, would it still count as human-powered if you charged the batteries first using a bicycle and a dynamo?
MaxwellBuchanan, Mar 24 2012

       Incidentally, the webternet says that a decent cyclist can produce 6W/kg, or 500W (0.7HP) for an average bodyweight. This is higher than I thought.
MaxwellBuchanan, Mar 24 2012

       That's a peak output for a few seconds, Shirley, not sustained. <googles> Or not ...   

       My web says, "A world-class cyclist will generate 0.65 hp for a 1-hour time trial -- all-out effort. Most recreational cyclists generate about 0.35 hp for a sustained (2 hour) ride."   

       By the way, the "horse" in horsepower was a Welsh mine pony, not a mighty Clydesdale stallion.
baconbrain, Mar 24 2012

       // Now that man-lifting electric helicopters exist, would it still count as human-powered if you charged the batteries first using a bicycle and a dynamo? //   

Alterother, Mar 24 2012


       OK, how about a clockwork man-carrying ornithopter, which is wound up over a relaxed afternoon by gentle pedalling before making a short but spectacular teatime flight?   

       Also, did we ever agree on why flapping flight was preferable to something more efficient?
MaxwellBuchanan, Mar 24 2012

       No and no.
Alterother, Mar 24 2012

       OK, how about a Liposucteropter? An array of needles, a series of tubes, a diesel engine...
MaxwellBuchanan, Mar 24 2012

       //flapping flight... preferable// 'cuz the energy transfer can be made directly from the legs to the wings: hell with the bicycle chain: pushing a leg is the downflap, and pulling it back up, which requires much less power, is the upflap.   

       "chiropterthopter" instead of "ornithopter".
FlyingToaster, Mar 25 2012

       If there's not a human in the craft providing direct power to the flight mechanism, it's not human-powered flight. An electric aircraft run on bicycle-charged batteries is still an electric aircraft.   

       I don't make the rules, I just selectively enforce them.
Alterother, Mar 25 2012

       I've been puzzling over [bigsleep]'s power = sink rate * weight.   

       For a start, //Energy input required per second = mgh = 100Kg x 10 x 1 = 100 Joules// is wrong; 100 x 10 x 1 = 1,000 (not 100). I thought 100 watts seemed suspiciously low.   

       Also, you need to factor in the efficiency of converting mechanical power into lift^H^H^H^H forward motion - which includes drive-train and propulsion losses.   

       Which explains why human powered flight is just barely possible. Sure, you can get better than 17:1 lift-to-drag ratio, but not vastly better.   

       The trick to efficient flight is to tune everything to one set of parameters - power, air-speed velocity, etc. Which is partly why ornithopters are troublesome - the wings are not in an aerodynamic steady state, and so can't be efficient at all times for any given shape. Birds, of course, dynamically vary their wing shape to overcome this, but that's something we haven't learned to engineer very well.
spidermother, Mar 25 2012

       I might go for two rigid horizontal wings that each went up and down--like a biplane getting taller and shorter--but two wings flapping from the roots like a bird isn't worth doing.
baconbrain, Mar 25 2012

       That's been tried, [baconbrain]. Never really took off...   

       Flight, like bicycles and engines, has had so many millions of hours of pondering and tinkering that all the simple variants have been thoroughly worked through.
spidermother, Mar 25 2012

       It is though. Not like a bird, like a dragonfly.
Sorry [spidermother] your anno beat mine by seconds.
Vortices from the weaker leading wings can be pushed off of by the stronger rear wings.
I don't just expect to be able to fly by human power alone but to hover as well.

       //I don't make the rules, I just selectively enforce them.//   

Storing energy once in flight is well within the rules, but lift off has to be completely manual or it's just another motor.
Decreasing the weight of the aircraft does not violate this rule unless it becomes lighter than air with occupant/s.

       It's ok.
I conferred with Leo and he's cool with it.

       Personally, I find the idea of storing energy, even during flight (except as altitude and speed), contrary to the spirit of human powered flight. Man pushes on machine. Machine pushes on air. Machine flies through air. Endy story.   

       The dragonfly may not be such a good model. Insect flight works very differently, simply because of the scale. Just for a start, note that insect wings are often flattish, rather than curved aerofoils like bird and aeroplane wings. Viscosity and vortex interactions are far more important than conventional lift at their scale.   

       Also, in terms of efficiency, four wings good, two wings better. Insects, vertebrates, and aeroplanes all generally evolved in that direction, for good reason. There are exceptions, of course. The dragonfly represents the main ancestral insect pattern - two rather similar pairs of wings, beating out of phase. Their survival shows that it's a valid configuration, but the evolution of variants shows that it's not always the best.   

       Bees are a particularly cool example. They have two pairs of wings. During ordinary foraging flight, they lock together, forming a single, efficient pair. But when they attack, the wings are allowed to separate into two independent pairs. That (I suppose) allows for high speed, high power, but low efficiency flight - precisely what's best for attacking over a short distance. It's like a propeller-powered long-range bomber transforming into a jet-powered interceptor. Note also that dragonflies are just that - interceptors, rather than endurance flyers.   

       Anyway, my point is that (a) insects are way cool, but (b) you probably want to copy a high-efficiency, large-scale animal, such as a condor or an albatross.
spidermother, Mar 25 2012

       I must take exception [spidermother].
I mean, c'mon, you knew I would.

       //I find the idea of storing energy, even during flight (except as altitude and speed), contrary to the spirit of human powered flight. Man pushes on machine. Machine pushes on air. Machine flies through air. Endy story.//   

Man pushes on machine. Machine pushes on air. Machine flies through air and any energy in excess of these requirements can be stored for later use.
Endy story.

       I understand thinking that if it were more advantageous for birds to have four wings rather than two that nature would have filled the niche, but I feel that this supposition is incorrect and based on food more than aerodynamics.
I get the scale differences but there was a time when insects had wingspans measured in feet rather than inches.
That the insects were out-competed on a large scale by birds does not render the design inferior flight-wise, just survival-wise.
As for two winged flight design being superior I would point out that there is only a single species of bird that has managed to pull off the trick of hovering yet there are many insects capable of it.

       Thank you for that factoid about bees wings.
I'd never heard such a thing. Too cool.

       For glide ratio four shorter wings are better than two wings of the same length.
For situations where two wings are better the bee analogy would seem to prove that four wings can become two wings easilly enough if necessary.

       //dragonflies are just that - interceptors, rather than endurance flyers//   

       Search for dragonfly migration to see their endurance, and, condors and albatross can neither hover nor store energy while gliding.   

       I know that stating that I'm right about this can not be counted as corroborating evidence but...   

       I'm right about this.   

       You'll see.   

       Actually there is a way to do this, you need four people.   

       Tie a rope to three of the people, attach other end to a generator, push them off a tall building.   

       Save the electricity to nicad batteries and use them to servo -boost the strength of the one remaining person (me).   

       So, entirely by using manpower, a person can fly.
not_morrison_rm, Mar 25 2012

       It seems to me that if you made a weighted pendulum out of the legs (with a fin) and then had big semi rigid wings capable of cupping and almost bending all the way around on themselves, and had the flyer do a crawl-style stroke, that each stroke would turn into a leveraged scoop of a figure eight and you could probably take off from a stand still -- rather than have to gain speed and try to screw around with gliding and all of the herky jerky chaos that the speed necessary for it entails.   

       Looking back on the fake video -- I was fooled -- but I did have one reservation, although i was quick to give it up in exchange for what I thought would mean being able to bring up the topic of human powered flight in everyday conversation, rather than continuing to pretend like I am interested in what i do for a living. The one thing that bothered me was that his flight was so herky jerky, as are all the other ornithopter experiment videos on the web -- I guess it would have to be to make that kind of flapping flight work -- but in my mind it is such a smooth and fluid motion, from a stand still, with much longer and slower strokes where the wings cup volumes of air and then push down and slip across them rather than slipping chaotically from gliding speed to undulation.
JesusHChrist, Mar 25 2012

       Again, that brings us back to the variable dynamics of a bird's wing, which we have yet to duplicate in any form light enough to get off the ground.
Alterother, Mar 25 2012


back: main index

business  computer  culture  fashion  food  halfbakery  home  other  product  public  science  sport  vehicle