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Human-powered Helicopter Fails to Lift Off
Peter writes "The Human-powered helicopter didn't even get off the ground. A team of University of British Columbia engineering students tried to win the $20,000 US prize offered by the American Helicopter Society. Three metres off the ground and hover for a minute was the challenge. But before the rotors were able to produce enough buoyant force they hit each other. More details: Vancouver Sun."
I dunno, for some reason, the second half of that headline seems pretty predictable after reading the first half :)
...not getting off the ground makes it difficult to crash.
Show me on the doll where his noodly appendage touched you.
But killing humans and using them for fuel? That's horrible!
... He'd have provided more engineering graduate students.
The little guy just ain't getting it, is he?
"My feeling at the moment is that the machine is actually quite unstable," said Mike Georgallis, leader of the team that has been working on the project for six years.
Maybe they did know that this wasn't likely to be a success.
Cheers,
Erick
http://www.busyweather.com/
Peter writes "The Human-powered helicopter didn't even get off the ground. A team of University of British Columbia engineering students tried to win the $20,000 US prize offered by the American Helicopter Society. Three metres off the ground and hover for a minute was the challenge. But before the rotors were able to produce enough buoyant force they hit each other.
I assume 'they' refers to the rotors, not the team...
This is kind of a nitpick, but buoyant force has nothing to do with how helicopters work, blimps and boats use buoyancy, helicopters and planes use aerodynamic lift.
"I'll have a Guinness, no wait, make that a Coors Light" -Grad student I work with, who shall remain anonymous...
The point is that this type of research could lead to more efficient lift mechanisms for conventional aircraft. Allowing longer flights with less fuel requirements.
BTW, the Australian Parlament(sp?) past the free trade agreement, so we now have software patents, yay!
it is only after a long journey that you know the strength of the horse.
IANAAerospace Engineer.
From reading their Project Status/Schedule page, it appears their problems may have arisen during the manufacturing stage:
July, 2004
It has been a while since our last update. We have been busy.
COMPOSITE SPAR MANUFACTURE/TESTING
All spars have been cooked including the tapered sections. Assembly of all this is complete for the four wings. Static testing was carried out for the assembled spars. All four eventually passed the test (see Thunderbird Projects - Picture gallery).
WING CONSTRUCTION
All four wings (for the two rotors) have been completed. This includes all wing parts (leading edges, trailing edges, suction side,
"Eventually passed the test"? Uh oh.
[There were no updates from December 2001 to July 2004]
December, 2001
COMPOSITE SPAR MANUFACTURE/TESTING
Static testing has been carried out for the CFRP spars. Static tests included both bending and torsion. A large effort was put in manufacturing the tapered mandrel for tapered composite spar production. One tapered spar has been manufactured with disastrous results. The tapered mandrel still requires some work (modifications). Composite spar manufacture continues (including straight sections).
It appears there were construction issues early in the project.
I am certainly not knocking their efforts. However, even the most elegant design can be compromised by sub-optimal manufacturing/implementation resources. I wish them the best in the next iteration.
I want to drag this out as long as possible. Bring me my protractor.
here are the rules of the competition.
The obvious cheats (lighter than air gases, storing energy in a battery) are banned, but you could 'cheat' by using a human to store up a lot of energy in a low-drag rotor that then changes angle of attack to convert the stored energy to lift.
A pizza of radius z and thickness a has a volume of pi z z a
BECAUSE it's cool, because I look at it and go "damn, that would be quite the engineering accomplishment right there," because college isn't all about inventing things that need to be invented, it's about expanding the mind to accomplish abstract ideas. Think of every lab that students do in their science courses: what's the point of those? It's old technology, it's certainly been done before. Why aren't freshman chemistry students working on cold fusion or something else the military will jump all over?
Besides, this is impressive science, since the human legs can put out a sustainable 100W, it's the attempt to built something light enough to get off with minimal power. And the $175,000 they've spent over 6 years to educate students and built a prototype is cheap in the education world.
Never underestimate the power of human ingenuity. For many years the thought of sustainable human powered flight of any kind was considered an impossibility but in 1979 we saw the Gossamer Albatross cross the English Channel. I believe that sooner or later someone will manage to meet the requirements to win this American Helicopter Society prize. However without a doubt even then human powered flight will be just an interesting curiosity and not of any practical use.
The human body constantly generates an approximate 200 watts. In case anyone's wondering, that's about 0.26 horsepower, and that's assuming that you can apply the full 200 watts of your energy. It's fun to see them try, but the physics say that the energy just isn't there.
That's not entirely accurate. I think the 200 watts is an approximation of the heat we emit in room temperatures. That's not the only source of power we have. We can also, for example, pedal.
Considering that we can run uphill fairly fast, the physics indeed says the power to overcome gravity most certainly is there, atleast for short periods of time. It's another question entirely wether we have the power to lift ourselves and the helicopter machinery using that technique. It will mostly depend on the efficiency vs the weight of the machinery.
1 Earth is warming, 2 It's us, 3 it's royally bad, 4 we need to take action NOW
The human body constantly generates an approximate 200 watts
You mean the average human...
Lance Armstrong can sustain power outputs around 600 watts, and several people (most competative amatuer cyclists) are capable of a ~1 minute burst of over 1250 watts.
"I'll have a Guinness, no wait, make that a Coors Light" -Grad student I work with, who shall remain anonymous...
The art of flying is learning how to throw yourself at the ground and miss.
(S(SKK)(SKK))(S(SKK)(SKK))
So not only am I paying top dollars to fly to europe, now I'm going to have to pedal for 8 hours too? Great.
Eh.
Attention passengers, we're preparing for take off. Please put your seats in the upright positions and your feet on the pedals. If you notice a fellow passenger failing to pedal, please quietly alert a stewardess that you suspect terrorism.
They have done their tests, and they have a guy which can do well beyond 500 watts, that's a lot.
The next thing is of course to make the helicopter lighter, and optimize everything for efficiency.
At some point, energy demands will get low enough, and then you may have liftoff. I think you're a bit too pessimistic. It's not easy, but that's not why they do it.
Employee of Inrupt, Project Release Manager and Community Manager for Solid
that the theory "helicopters can't fly; they're just so ugly that the Earth repels them" is incorrect. Oh well, back to the old drawing board...
"the atmospheric conditions caused a dangerous imbalance in the craft's two rotor blades: the bottom blade was producing lift while the top blade wasn't." Sounds to me that what really happened was that they tried to save weight and didn't make the upper blades, which are longer, torsionally stiff enough. This caused a phenomenon similar to aileron reversal: as you produce lift, you produce a nose-down pitching moment which can elastically twist the blades, and may be capable of reversing the direction of lift. If this is what happened, then I can easily see the upper blades flapping down into the lower set of blades.
This aileron reversal effect is actually a fairly hot research topic in the rotorcraft community. People are trying to exploite it by using embeded actuators to control trailing edge flaps to create a pitching moment to twist rotor blades and thereby eliminate the swashplate for primary control.
"The result was an ugly collision between the two less than one minute after the team made its first attempt at flight, around 11 a.m. Seventeen minutes later -- after a roll of cellophane was used to repair the damaged wing -- the team tried again."
That doesn't sound like massive damage to me, if they were able to patch it up with a roll of cellophane -- in 17 minutes. Sounds like part of the blade cracked or got smashed in, and that's it.
At which point, they continued the test:
"This time, the chain connecting pilot Peter Hudson's pedals to the top rotor snapped. Continued problems with the chain led Georgallis to finally abort the day's mission."
Sounds like they decided to give up before they did any real damage to the helicopter. So, rendering thousands of hours at $30,000 dollars wasted? I don't think so.
People have a way of blowing things way out of proportion, don't they?
There is work being done on a microscopic scale in your muscles. You might need a background in muscle biology to completely understand this, but this is the modern theory of how actin and myosin (the two proteins which make your muscles work) actually cause muscle contraction.
Basically, your muscle fibers are made up of billions of tiny ratchets which cog against another fiber, kind of like a rack-and-pinion steering system. When your muscle is applying force to an object, say, when doing a chinup, the ratchet teeth "slip" and the fibers slide past each other. To counteract this, the ratchets must flex again to pull the fiber back. All this ratcheting work eventually winds up as heat in your muscles.
If your arms were made of steel, it would take no energy to hold a chinup. This is because steel arms have no moving parts. It is important to know that your muscles are indeed still "moving" while holding a chinup, but at a microscopic scale you are not aware of. That's why it requires an exertion of energy to maintain a flexed position.