Human-powered Helicopter Fails to Lift Off 410
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."
Heliman... (Score:3, Interesting)
I've seen machines in the past that are glider-based, and a human could actually keep them in the air for a fairly long time. But a helicopter? I wonder what they're trying to accomplish here. I mean, obviously the students are trying to win $27,000, but I have to wonder what the American Helicopter Society is thinking. Vertical flight always consumes a heck of a lot more energy than horizontal. I'd like to see more effort put in to human-powerd glider projects.
Re:Point? (Score:5, Interesting)
BTW, the Australian Parlament(sp?) past the free trade agreement, so we now have software patents, yay!
Design vs Implementation (Score:5, Interesting)
IANAAerospace Engineer.
From reading their Project Status/Schedule [mech.ubc.ca] 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.
Re:Point? (Score:3, Interesting)
I imagine that the purpose was to stimulate interest in:
-Helicopters
-Mechanical Engineering
-Engineering/Science generally - you know, those strange subjects they used to teach in school before everyone decided they were too hard and made the less bright kids feel bad.
Re:Will someone hep me? (Score:2, Interesting)
Cheers,
Erick
Possible? (Score:3, Interesting)
So once they figured this out, they thought it would be funny to watch people try? I'm having flashbacks to the movie "Chicken Run."
That should read average human body... (Score:5, Interesting)
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.
Re:Does strike me as feasible (Score:3, Interesting)
Previous attempts at such a prize (Score:3, Interesting)
Human Helicopters (Score:3, Interesting)
POINT 1: Can someone comment on the maximum sustained (3 minute duration) power output of a well trained human body? I believe it's less than one horsepower... ("he was stronger than a horse"), but not by much.
Regardless, it seems to me the components on a controllable helicopter include a Sikorski rotor assembly (that allows different angles to be put on a blad depending on it's position in a rotation). That dictates towards rotor blades that can occilate rapidly, and thus can very strongly stand up to high-speed torsions as well as flexing.
POINT 2: Since the blade structure is complex, and the rotors must be quite powerful, it seems to me that dictates tight restraints on design given the weight must be severely limited. Is there any discussion of exotic materials used in any other news article? I suspect a lot. What would the rotor blades be made from, standard materials like commerical helicopters?
POINT 3: I suppose the competition prevents someone from using a power storage device like a big battery or flywheel that a person can pump up to accumulate energy?
POINT 4: Does "Human Powered" mean chemically? Suppose I dried and accumulated enough of my own "dung", then burned it to distill alcohol, then used that alcohol as fuel in a conventional helicopter, it would be "human powered"... (grin).
Re:Does strike me as feasible (Score:2, Interesting)
Here is a helicopter [rotor.com] with a dry weight of 254 pounds. It's engines generate 55 horsepower (41 kilowatts [google.com]) to get itself and one passenger off the ground.
And couldn't they store up the energy into a big rubber-band, by ten minutes of human energy, let it go and add more energy as it goes up?
Of course. Watts is only a way of measuring constant energy flow. Convert to Joules and you can figure out what it would take to get off the ground. e.g. If we say we require 10 kw of power to get off the ground, we find:So assuming that we had a storage medium capable of containing the energy at 100% efficiency (not bloody likely), then our pilot would have to pedal for nearly a minute before takeoff.
The question is, what does he do once he's in the air? Once his stored energy is exhausted, he's back to using only what he can generate. If what he generates is insufficient to produce enough lift, he's coming down.
Now if you gave the thing wings and enough forward thrust, then he *might* be able to stay aloft on 200 watts. I still wouldn't count on it though. I remember a little 1 horsepower plane on the discovery channel, but that's still about four times the power a human generates!
Materials Science, not Engineering challenge (Score:2, Interesting)
The only way I can imagine this working is with a really strong spring that weighs almost nothing being used to store a few hours of pedaling, to be released over a period of 3 minutes. Maybe in 100 years, when we have nano-technology to make everything out of carbon-nanotubes and diamond monofilament, okay, maybe then. But from the looks of it, they'll add that to the "cheats" list.
I'm surprised they didn't just come out and say "Make a working pedal-power helicopter out of granite and mud. You may use power tools, but only those made of pudding."
Climbing Mt Everest is a difficult, but sane, goal. Climbing the smoke from a campfire is nuts, no matter what school you're studying at. (yes, even MIT.) Anyone who has ever tried climb the rope in gym class knows how hard it is to lift oneself three feet off the ground. And that's with a nice, solid rope in your hands!
This reminds me of the Dilbert cartoon where they are supposed to build an integrated global supply chain using only post-it notes and a toothpick.
This is a great argument against the use of psychedelics when reviewing project specifications. I'm sure the kids had fun, though. Good for them.
blades not stiff enough? (Score:5, Interesting)
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.
Re:Just a question... (Score:3, Interesting)
There is an optimal range of rider cadence. For sustained riding, this is generally in the 80-11o rpm range. Experienced track cyclists can get to around 200rpm for short bursts.
There is also an optimal rpm for the rotors, based on airfoil shape(lift generated), rotor material strength, and amount of weight it has to lift.
Adjust the gear ratio as needed, to get the optimal rotor RPM at the same place at optimal sustained rider cadence.
Shifting gears as on a normal bike would serve no useful purpose. If they get the rotors to 1000 rpm, but they fly apart due to material failure, that's no good.
Human combustion is still a risk (Score:2, Interesting)
That's not the only danger though. If you read the competition rules at vtol.org, it's clear that the crew is allowed to burn their clothes, hair, and limbs to generate lift.
Personally, I hope that none of them is quite that committed to the challange. Maybe if the prize were closer to a million
Re:Does strike me as feasible (Score:3, Interesting)
http://www.lancearmstrong.com/faq.html [lancearmstrong.com] points out that Lance produces around 250 watts during an endurance ride (2-4 hours). For sustainable travel, I think that we can comfortably state that most potential helicopter pilots will not be in better shape than Lance.
His burstable power is around 600W, but there's no point in being able to get yourself 30 meters up off the ground and then need to take a break for a minute...
Crazy (Score:2, Interesting)
Can't tell from the pictures if there really is a gear shift but it doesn't look like it.
Add a gearshift and use one pair of lift blades as well as a tail rotor
Shorter blades are likely better. The long blades may require fewer RPMs but the tips of the long blades will be really moving (v = wr) anyways.
A reasonable design is to take a real helicopter, strip the engine and other paraphernalia out of it and install a multi-person pedal system. Then test the endurance of an average person carrying a weight up a flight of stairs for one minute. Take 1/2 to 2/3 (maybe 1/4 or 1/5 depending on helicopter efficiency) of the maximum weight carryable, divide the weight of the helicopter by this weight to obtain the number of people required to pedal
Huge Glaring Problem. (Score:2, Interesting)
Now, helicopter. It is no accident that no one has ever successfully glided a helicopter in to land. They have the aerodynamic qualities of a blue whale. Even if you could get it to work, and I honestly have no doubt that they can, at least far enough to get three meters off the ground, or whatever it was they needed. As for actually flying anywhere? Not only does manuvering seem like it would be really awkward, but the effort involved would be ridiculous.
You know (Score:3, Interesting)
As if high school didn't hold me back enough as it was... High school without even honors math/science? *shudder*.
Thank God for taking part-time classes at Rutgers my senior year of HS when I ran out of things to take there.
Re:That should read average human body... (Score:5, Interesting)
Your weight in lbs x floor to floor height in feet / seconds to climb / 550 = horsepower
Don't live in the US?
Your mass in kg x 9.82 x floor ht in meters/ seconds to climb = watts
Re:How about bulking the pilot up with steroids? (Score:2, Interesting)
Use of drugs is prohibited by the rules [vtol.org]:
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.