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78 Comments
- diggan8, on 09/03/2009, -1/+27Per the contest rules:
"4.2.3 No drugs or stimulants shall be used by any member of the crew. An assurance must be given to the official observers at the time of the attempt that this requirement has been met."
That's too bad. See, I invented this already.... and flew it through a rainbow that was bleeding apples while purple unicorns shot lasers out of their horns. - diggopolous, on 09/03/2009, -1/+26Contest over. Winners are a Mr. Flinstone and Mr. Rubble.
- s4g4n, on 09/03/2009, -2/+25roflcopter
- snowcase, on 09/02/2009, -2/+23What happens when they get tired? Isn't that the reason we invented engines in the first place? So we didn't have to work?
- inactive, on 09/03/2009, -1/+18This can't possibly end badly...
- diggydougie, on 09/03/2009, -0/+14It's really more about getting the efficiency to the point where it is possible. Then taking the lessons learned to machine powered craft.
- inactive, on 09/03/2009, -2/+14What about this helicopter i wind up with an elastic. Its human powered. 250k thanks..
- tacodealer, on 09/03/2009, -2/+14HUMAN-POWERED HELICOPTER FUEL IS PEOPLE! WE'VE GOT TO STOP THEM SOMEHOW!
- blqysmg, on 09/03/2009, -0/+9Um, *****. I'm not saying that we will ever achieve human powered hovering flight, but when you say that human powered airplanes work because wings provide lift, what the hell do you think the rotors on a helicopter do? Beat the air into submission? They ARE wings, and by moving through the air they provide lift.
The human powered airplanes required help from outsiders because they are not stable when moving very slowly. The propeller provides the thrust to move the plane forward through the air, causing the wings to produce both lift and drag.
If there was a wind blowing strongly enough that the pilot of the human powered aircraft could use for stability, he wouldn't need any help keeping the craft stable. He could just accelerate to flying speed and take off while using the control surfaces to keep his aircraft correctly aligned to the apparent wind. - nurbsenvi, on 09/03/2009, -0/+8Is that even physically possible?
- diggydougie, on 09/03/2009, -0/+5Lance? Are you available?
- bahawkid, on 09/03/2009, -1/+6another way to die in cramps.
- UselessTrivia, on 09/03/2009, -0/+5The bernoulli principle applies to helicopters as well.
Once a person has built up enough momentum the bernoulli effect will maintain lift through the conservation of forward momentum.
In the case of a rotating wing aircraft you are simply substituting the conservation of forward momentum for the conservation of angular momentum.
The main reason fixed wing flight is easier is because the only friction that impacts the bernoulli effect is drag in the form of wind resistance. With a rotary aircraft you have wind resistance as well as friction from the rotors, so it takes a little more energy.
That problem will never go away, but that doesn't mean it's impossible to minimize the impact through good design. It's all about power to weight ratio. Put a strong enough guy in a light enough frame and you can make it work. - lead2thehead, on 09/03/2009, -0/+5I'm not sure you could afford to hire him for 60 seconds.
- mydigglogin, on 09/03/2009, -1/+6You never got in a bucket and then lifted it up? (I wonder how many will try after reading this)
- HonoredMule, on 09/03/2009, -0/+4You tell me. Is it possible for a human to generate enough force to lift the equivalent of his own body weight? If so, then the question of possibility comes down to how efficiently human strength can be translated into that force when pushing against air, and with how little added weight from the apparatus that enables it.
That the lift must be generated via downforce on an atmosphere with little resistance does /not/ increase the energy that is absolutely required to do so. It is the loss of efficiency from translating energy into downforce on said atmosphere pushing back that does. The reduction in "opposite reaction" from the atmosphere means that much energy gets spent against inertial or centripetal "opposite reactions" instead.
Fixed wing designs (planes) provide more favorable efficiency in their basic design, but the advantages can be worked into helicopter designs as well. A large number of small fans would probably work better if not for the horrible amount of weight and mechanical inefficiency that then becomes hard to escape, but other systems of better translating the energy can be imagined yet, in addition to finding stronger and lighter materials with which to scale up existing ideas. - surf1punk, on 09/03/2009, -0/+4Get to the choppa!!!!
- rob132, on 09/03/2009, -1/+5Only if one of them flaps their arms.
- blqysmg, on 09/03/2009, -0/+4So, the question becomes "how much power is required to successfully lift a human sized payload to three meters and hover for one minute using helicopter style rotors."
- rob132, on 09/03/2009, -0/+4Clearly not, as the video showed a Japanese team doing such a thing.
- pjvdg, on 09/03/2009, -1/+5Don't worry, they will only take those that can't afford health insurance.
- blqysmg, on 09/04/2009, -0/+3That is one of the BEST explanations of how a wing flies that I've seen on the Intertubes. Most people just invoke Bernoulli, without having any idea what the math that he came up with actually means. Bernoulli's equations were actually calculations of pressure changes of a fluid INSIDE A TUBE caused by a constriction in the tube. As stated by Bernoulli, the equations produce a very close approximation to the pressure difference a shape makes going through the air (since air is a fluid) if (and only if) there is a second, imaginary, shape placed near the shape so as to form a constriction of the airflow.
Modern wing calculations already incorporate the math needed to simulate both shapes, so we don't have to actually manually double the calculations (or cut them in half, as the case may be.)
I may be wrong (and if I am, I'm sure someone will tell me, but as I understand it the "pressure difference" between the top of the wing and the bottom of the wing as calculated by Bernoulli's formulas never exactly matched the actual lift achieved by the wing, either. A whole lot of other calculations had to be added in to correctly model the wing.
At the NASA website, they use the explanation that HonoredMule just gave for how a wing flies. The shape moving through the air displaces air at a certain rate and in a certain direction. The kinetic energy imparted to the air by the passage of the wing is reflected in deflection of the wing in the opposite direction (not necessarily "up," since we don't know the orientation of the wing.) - CptBuck, on 09/03/2009, -0/+3How big would the blades need to be? This is NASA's bicycle plane (as I understand it, the first successful one ever made.)
http://pro.corbis.com/images/IH015314.jpg?size=67& ...
as you can see, the wings are massive in comparison to the person.
I'm also not sure a person has the strength to turn rotors of the necessary size. I mean, look at the nasa plane, the way it works is that you spin up a small propeller and as you build speed on that small propeller, the overall craft accelerates to such a speed that you get sustainable lift.
Imagine if this person instead had to peddle the entire wing structure....
Nevermind that a person would *also* have to peddle the stabilizing rotor or else the entire thing would go out of control from the torque. - Xzelick, on 09/03/2009, -3/+6The only way it would be possible is if you charged up some sort of battery, capacitor, spring, or another type of "potential energy battery" prior to the flight using human-power like a crank or pedal.
- HonoredMule, on 09/03/2009, -0/+3The video that's /right there in the article/ proves you wrong.
- blqysmg, on 09/03/2009, -0/+2Instead of the gearing going to swing the entire rotor, what if the "engine" were used to turn a propeller mounted on the front of a wing, and another propeller mounted on the front of another wing, with both of these connected to a central hub.
Sort of like two of the Gossamer human powered aircraft facing opposite directions and glued together at the wingtip. We know the aircraft will fly, they've demonstrated that. If they can achieve flight in a straight line, then they should be able to achieve flight while spinning around a central point. The inner half of the "wing" will produce less lift, but the outer half will produce much more lift, since it's further out on the circle and therefore will travel much faster.
Also, with propellers "powering" the rotors around there is no torque applied to the central hub to counteract. - CptBuck, on 09/03/2009, -0/+2You'd need to have a low gear ratio to get the blades spinning fast enough to get enough lift off the ground. When I said "I'm also not sure a person has the strength to turn rotors of the necessary size" I didn't literally mean turn them at all, I meant turn them fast enough.
- Jektal, on 09/03/2009, -1/+3Step 1. Embed nuclear material into arm
Step 2. Build nuclear reactor with arm-hole
Step 3. Place reactor in helicopter
Step 4. Win $250,000 - Ductapemaster, on 09/03/2009, -0/+2Did you even read the article? There is a video at the bottom of a human powered one.
- T8erT0T, on 09/03/2009, -2/+4Your move DaVinci!
- Colecoman1982, on 09/03/2009, -0/+2I believe that the point HonoredMule was trying to make was that the progress shown in the video suggests that previous accomplishments are good enough to justify saying that you're talking out your ass when it comes to knowing whether or not this can be accomplished without some kind of energy storage technology. Of course, it's easier for you to save face if you answer obtusely and cling to pedantry rather than acknowledge the likely fallacy of your simplistically pessimistic blanket statement that it simply "can't be done".
- HonoredMule, on 09/03/2009, -1/+3Really? I "provide enough force to get off the ground" every time I do a chin-up. Clearly it IS possible given sufficient efficiency of power being translated to lift. Besides, has no one even GLANCED at the article we're supposedly discussing?
The videos and bulk of the text itself shows/describes human-powered helicopter flight that has already been accomplished. The device shown lifted off and flew without on-the-ground help or any non-human force for 19.46 seconds at a height of about 2 feet.
The prize isn't already handed out only because the prerequisites aren't simply any human-powered helicopter flight, but one lasting 60 seconds at 3 meters. - scottblystone, on 09/03/2009, -0/+2That's against the rules, unless it is the lift mechanism itself.
- Colecoman1982, on 09/03/2009, -0/+2A number of the other projects that have tried, or are trying, to win this prize have already used counter-rotating blades similar to how the chinook works, but usually stacked directly one on top of the other.
- blqysmg, on 09/03/2009, -0/+2Control is an issue, perhaps a "twin engine" model based on a Chinook might be the best plan.
- Nerys, on 09/05/2009, -0/+1The video is amazing though I have to wonder if its really a helicopter. seems more like a ground effect machine or "hover craft" to me since it was never able to go "higher" no matter how hard he pedaled.
Still utterly amazing! I hope someone gets it! - Colecoman1982, on 09/03/2009, -0/+1Sorry Mike, your ignorance and limitation of perception are showing.
"The problem is how the lift is formed in a helicopter. Since the lift is created by the blades and not by a fixed wing it is going to require more work to sustain flight, where as in an airplane the hardest part is take off. Once moving you can glide and stay in flight and stop requiring the input force to keep you in the air. The Condor was really a glider more than anything else. However take the power off a helicopter and you stop flying."
I don't think I've seen anyone suggest that building a human powered helicopter isn't more difficult than building a human powered airplane. I tend to think that most people who have read the article assume that by default considering that decades after the former was accomplished, the latter is still incomplete despite a lot of work on the subject.
"Now to work out the physics behind how much force a human would take to lift himself off with a helicopter would take me a month to work out, but it doesn't take a genius to know that people just don't have the strenght. maybe some atomic powered supermen, but nobody else would."
Actually, the math should be, relatively, simple. We know that humans can do pull-ups and we can assume an almost 100% mechanical efficiency in that operation (I'm sure it's less than 100%, but the higher assumption works in your favor). Now, we just need to figure out the highest theoretical efficiency for an ideal propeller (which I seem to remember being in the 70% range but I'm sure there are places to look that up), add weight to the hypothetical pull-up artist equivalent in percentage to those mechanical losses, and then add in the weight for any given helicopter design (which seems to average about 70 pounds over a number of the projects). Your simultaneous belief that "it doesn't take a genius to know that people just don't have the strenght", and unwillingness to get off your ass and crunch the numbers needed to show it, just proves that you're talking out your rectum and that this statement can't be taken seriously.
"To be a real human powered helicopter it would need to take off and fly around at which point you are going to need a tail rotor or a second set of lifting rotors like in a Chinok."
Sorry, this is the English language, not the Mike-lish language. You don't get to redefine words to suit your personal opinion. There's no, set-in-stone, rule that something needs anything more that powered rotating blades and the ability to go up and down in order to be considered a helicopter.
As for how stability and maneuverability could be accomplished, there are already a number of these projects that make use of counter-rotating blades to eliminate the need for a tail rotor. If you really wanted to add the ability to turn, you could always just look for a little person (as using children would probably run into legal issues) and/or add multiple riders in tandem to the machine (which is allowed for in the contest rules). Laws of scale mean that each additional person requires, significantly, less that a doubling of the vehicle weight and should, eventually, make it possible to compensate for the added weight of a very light pilot (such as the little person I mentioned).
"really so these are some kind of magical blades that don't get slowed by the friction of the air? secondly the linear momentum of an airplane is much easier to maintain because the work is going to providing thrust, not the lift itself. I'd pick apart the problems with the rest of your post but my wall of text is already big enough."
No, there aren't any "magical blades" but designing airfoils to minimize the coefficient of drag while maximizing the coefficient of lift has formed the basis for an entire field of engineering research for over half a century. Again, no-one had claimed that it's not a more difficult problem than human powered planes. Nice straw-man argument you keep harping on there.
"blqysmg - the condor will not take off simply by pedaling really really hard - those people are their to stabilize the craft and help provide the initial thrust"
Only half right. They are there to help stabilize the craft (as is allowed by the contest rules). However, they are, explicitly, not there to provide the initial thrust (which is, explicitly, banned in the contest rules). Really, are you just making this crap up, as you go along, to suit your argument?
"oh and I don't care that this contest is just about hovering - that isn't a helicopter. a helicopter can fly around places."
Again, we're all speaking English here, not Mike-lish. No-one cares about your warped, and arbitrarily limited, definition of what is, and isn't, a helicopter. - Jaime2000, on 09/04/2009, -0/+1http://www.youtube.com/watch?v=BJAtRlHFKMQ
Or, in Spanish:
http://www.youtube.com/watch?v=71QRoGLgl64 - unlimitedmp, on 09/03/2009, -0/+1It's a fairly simple process. The only problem is gathering the 50 lbs of refined flawless diamonds to make the machine.
- Nerys, on 09/05/2009, -0/+1not really. Remember a REAL helicopter spins very fast.
a human powered helo will not be like this. likely as seen in the demo video the rotor speed will be slower than running speed. - UselessTrivia, on 09/04/2009, -0/+1Mikesbaker, I was not talking down to you. If I was I'd say something like this:
Your'e a ***** moron. You have to do the same amount of work to provide thrust to a fixed-wing aircraft in order to create lift as you would have to do to create the lift itself. In fact creating the lift directly is almost certainly more efficient, just more difficult.
I never suggested it was somehow an easy thing to do, but rather that the same principle which keeps a fixed wing craft aloft (lift sustained by momentum) will apply to a rotary-wing aircraft as well.
It requires more energy because there are additional sources of friction and gravity does not help in the generation of lift as it does in a fixed wing craft, which will make the flight shorter for the same amount of energy, but then again it's doing something that a fixed wing craft can't do...maintain a constant orientation to the ground.
You are also monumentally missing the ***** point when you fail to realize that human-powered helicopter flight has already been accomplished. There'a ***** video of it embedded in the article...it was just a lower flight for a shorter time than required by the competition. It's only a matter of time before someone improves on the design or comes up with a better one and meets the target of 3 meters for 60 seconds. - blqysmg, on 09/04/2009, -0/+1HonoredMule, I see that the accomplishments to date are encouraging. I don't necessarily agree that I am encouraged enough to believe that 19 seconds at two feet is close enough to 60 seconds at 10 feet. In fact, the gap is pretty large. Yes, it is an incredible feat, no it's not good enough.
With large blades moving close to the ground, there is a well known effect that gives them extra lift. We don't exactly know why (most people believe it has to do with interrupting wing-tip vortexes.) Moving up to three meters won't move the craft completely out of ground-effect, but it will diminish the effect by a pretty good bit. Drag on the rotors will increase, causing even more power to be required for lift.
Great effort so far, and I wish everyone who attempts this the best of luck. It won't be easy. It might be possible. As with any effort of this type, it will take a very clever team and a very strong "pilot." - HonoredMule, on 09/03/2009, -0/+1Thank you, that was exactly my point, right down to the sarcasm and subtle derision for the obvious failure to check with the immediately available facts or even apply a little reason before speaking.
- nullcodes, on 09/04/2009, -0/+1A helicopter is kinda like two or more fixed wing airplanes rotating about a central point. The airplanes of course have no fuselage. Oh yeah and the flaps are being manipulated to
- blqysmg, on 09/04/2009, -0/+1I don't think it's actually possible, to be honest. It's just a thought experiment. Oh, by the way, Colecoman, I don't think a Chinook has counter rotating blades, just two sets of them. I could be wrong. It doesn't really matter, I guess. Either fore and aft like a Chinook or counter rotating on a single shaft like a NOTAR would work to make control issues easier.
I'm betting it would still take more than 10 horsepower to get off the ground, even at the most optimistic. WAY out of line for human power. - Colecoman1982, on 09/03/2009, -0/+1Sorry, your example is idiotic. There's no violation of Newton's laws in the premise of this contest (as there is in your example). A better example would be trying to do pull-ups with a significant amount of weight strapped to your body. The weight represents the large difference in mechanical efficiency between the direct action of your muscles/bones against the pull-up bar versus the lower mechanical efficiency of even the most efficient airfoil design. Sure it's difficult, and it is possible that the minimum required theoretical energy output is just higher than possible with human physiology, but no-one has produced any info (that I've seen) to suggest that and previous success in this field (such as the video in the article) suggest that it's close enough to be worth trying.
- Nerys, on 09/05/2009, -0/+1Not true. A helicopter is just as able to "glide" (its called auto rotation) as an airplane.
It just takes more work. - asskicker32, on 09/03/2009, -0/+1all you need is an ultralight frame, big light blades, and the mechanics of a standard helicopter. Some gyros, You only need a bicycle gear mechanism for both the top rotor and rear rotor. Have some reducers and gear changes for the differnece in speed between the top rotor and rear rotor...
On second thought, it has to be harder than that. That sounds too easy. - Nerys, on 09/05/2009, -0/+1Your right. Gigantic. Just like the impossible machine IN THE FRAKING VIDEO RIGHT AT THE BOTTOM OF THE DAMNED ARTICLE :-) hehe
- asskicker32, on 09/03/2009, -0/+1Uh, have you heard of gears?
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