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."

Comments

Wow

[Anonymous Coward]

Wow, a human powered helicopter! Great, I would be free from traffic congestion on my five minute commute to work!

Re:Wow

[RevDobbs]

I see... a methane burning engine, and "U of BC Engineers Go To Taco Bell".

I'd bet ya that a couple of Chimichanga Burrito Supream Stupidbigs would induce one human to produce enough methane to power a small 'copter for a 5 minute trip.

Re:Wow

[Anonymous Coward]

My dream: Get one of those helicopters. Drop drawers, and poop on one of those damn pigeons that has been crapping on my car over the years.

hmmm

[Anonymous Coward]

I dunno, for some reason, the second half of that headline seems pretty predictable after reading the first half :)

Look on the bright side...

[pyrrhonist]

...not getting off the ground makes it difficult to crash.

Re:Look on the bright side...

[boarder8925]

...not getting off the ground makes it difficult to crash.

But they can still burn! =P

Re:Look on the bright side...

[Epistax]

If only this were true in software.

That's just silly

[Anonymous Coward]

Everyone knows Canucks can't fly.

So no simulations or models or just spinning the rotors indicated this might happen?

Why did they bother in the first place?

[inkdesign]

"Right now we're all taking bets on what's going to fail first"

Sounds like this venture was well planned!

Re:Why did they bother in the first place?

[Phurd Phlegm]

"Right now we're all taking bets on what's going to fail first"

Sounds like this venture was well planned!

Actually, that's how you engineer something for the lightest possible weight. If nothing fails, you've overbuilt the whole structure. If something fails you beef that part up a little and try again. I imagine that light weight is really critical with this design, even if you can find a really brawny little bike racer to pump the thing. One of those guys that basically a pair of legs supporting a pair of lungs . . . .

Of course, you do it differently if there's human life involved, but I can't imagine a human-powered helicopter getting high enough for this to be a major concern.

I'm all in favor of alternative energy sources

[Anonymous Coward]

But killing humans and using them for fuel? That's horrible!

Re:I'm all in favor of alternative energy sources

[ssclift]

Here's your fuel cycle:

Human -> Liposuction unit -> Biodiesel unit -> engine...

The challenge then becomes one of shrinking the intermediate stages between human and engine. Fat is our highest energy density but we don't have the power density in our natural fat burning processes, hence, time for a little help from technology.

It would make the invention practical for most Americans. Maybe fast food chains would get behind the project... :-)

Re:I'm all in favor of alternative energy sources

[sharkey]

Soylent Diesel is .... PEOPLE!!!

Re:I'm all in favor of alternative energy sources

[Jeremi]

I find it amusing that liberals are the only ones who say we went to Iraq for oil. We were big customers of Iraq before the war, and we still are. We don't really care all that much about the regime of a country we buy from.

Then why did we go to Iraq? Every reason the Bush administration gave as a justification (WMDs, ties to Al-Quaeda, Iraqis wanted to be 'liberated') turned out to be false, so what does that leave? Was it all really just a colossal mistake? Or did Bush have a deep burning need to "save" the Iraqi people from their government -- so much that he felt the need to distort intelligence and fabricate exaggerated threats to in order to justify his actions? If that is the case, why aren't we "liberating" Sudan right now? (The genocide there is arguably worse, and unlike Saddam's past genocides, there is still time to do something about it)

I don't know the real reasons why we invaded Iraq, and neither do you. All I know is that the official reasons given by the Bush administration don't pass the sniff test, and therefore the real reasons must be something else. Given the Bush administration's penchant for secrecy and doublespeak, and their incestuous ties to the oil industry, it's not a surprise that oil comes to mind.

As for WMDs, the millions of Iraqi dead during Husseins reign as 'president' of Iraq don't bother you? Oh right - malevolent dictators can do no wrong!

The Bush administration claimed that Iraq possessed WMDs that could give America "a day of horror such as it has never known", and that "the smoking gun might be a mushroom cloud". Saddam slaughtering Kurds is a terrible thing, but it has nothing to do with cities being destroyed in the United States. If Bush wanted to invade Iraq based solely on humanitarian grounds, he should have made that argument and let the people decide whether it was worth it. But that was not the argument he made, so it's disingenuous to pretend now that it was.

If God meant for man to fly ...

[Bob(TM)]

... He'd have provided more engineering graduate students.

No pretesting?

[erick99]

How could they not know that this was going to fail so completely? The article did not state whether or not they had done any test flights before the public demonstration. If they did, and it worked, than maybe it was just the temp/humidity as stated. It was interesting to read:

"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

Re:No pretesting?

[Aardpig]

I thought that was what engineering is all about.

Not familiar with the Tacoma Narrows bridge disaster, are we?

Re:No pretesting?

[wwest4]

> These blades are huge, thick profile and with HUGE drag.
> There is simply no way a human can spin and keep them rotating
> for 1 minute at a speed sufficient for liftoff.

Yeah, but it's merely an engineering problem. All they have to do is reduce the blade profile by (thick/3.212) to get to (HUGE-SOMEWHATBIG)+3, give or take a few hundredths of a BIG and it just might work.

Could someone confirm my math?

Oh I admit, it LOOKS grim, but isn't it a bit presumptuous to be a naysayer without any real data?

Re:No pretesting?

[gl4ss]

did you do the calculations then, just now, and know that is impossible with their wing profile, or are you just saying so because you got a gut feeling that it wouldn't work?

Re:No pretesting?

[Phurd Phlegm]

These were engineering students, and yet no one thought to do the basic physics calculations (like: what is the power required and can a human generate it) before building a prototype. I thought that was what engineering is all about.

I know it's kind of expected that no one on Slashdot reads the references before pontificating, but this (click on "choosing the final Thunderbird design") seems to indicate they did do the calculations and they did expect a human could produce enough power.

It appears they were in error, or that there were other things (e.g., stability) that interfered. That's no reason to expect they won't improve the design and get it working, though. I think it's a pretty cool challenge and certainly beats the usual student project of "design another <known thing>".

Re:No pretesting?

[tgibbs]

How could they not know that this was going to fail so completely? The article did not state whether or not they had done any test flights before the public demonstration. If they did, and it worked, than maybe it was just the temp/humidity as stated. It was interesting to read:

Very probably, they didn't really expect it to work the first time (although I'm sure they had hopes). But hey, it's a university, so there's no real reason to hide the failures behind closed doors, and good educational reasons to do it in public. After all, failing and going on is a legitimate part of the development process.

Re:No pretesting?

[rtz]

Ugh, people are so stupid. Test things you morons!.

Well, they just did...

Re:No pretesting?

[Dave_B93]

I was at the attempted liftoff.

This was the first time that they had the whole thing assembled, and in some ways you could tell. I think some simple resistance based testing would've shown that chain structure was too fragile to propel the wings properly ( either that or the chain was somehow damaged in the first crash where the blades ran into each other.)

It was also kind of obvious they had never practiced how they were going to start the thing. they had 4 volunteers, (one on the end of each rotor) running around helping the rotors get started. One of the guys on the lower blades was pulling too far down causing the other guy to let go. That is why the blades collided the first time, forget all this not enough lift on the top blade, it was human error.

The second attempt (after repairing the damage caused by the first attempt). looked more promising, the blades actually seemed to be moving quite well, and in fact the upper blade had started producing enough lift that it looked like there was no danger of hitting the bottom one ( even with human error) , but then they ran into the problems with the chain. Imagine the sound that your bike makes when you're in the wrong gear going up a hill. The skipping noises etc... it sounded just like that.

I left after the third attempt when the chain just came off. it didnt' look like they were going to get anywhere, and I'd already been there for about 2 hours.

As for why they'd never practiced with the thing beforehand, I speculate that it is because they didn't know if the thing would survive. If somehow it had gotten off the ground, only to crash after 30 seconds, they would've beaten the record, but wouldn't be able to recreate it. This way they would atleast have witnesses...

They hit eachother!?

[TeVi]

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...

Nitpick

[TamMan2000]

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.

Re:Nitpick

[kidgenius]

Techincally, buoyancy force is the total volume of the fluid displaced multiplied by the density. That is how "lighter than air" craft are able to stay aloft. Aircraft, use lift.

Heliman...

[FlimFlamboyant]

Does this mean Lance Armstrong will soon become an astronaut?

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:Heliman...

[ericpi]

I agree that it's unlikely that human-powered vertical flight is quite unlikely to be practical anywhere outside of engineering demonstrations.

However, I would think that the point of the excercise is to lean new insights into helicopter design. It's (relatively) easy to get a copter off the ground with a nice, powerful turbine engine. But, if you want to get something working with 1/4 horsepower, you have to re-think a lot of 'accepted' designs in order to improve efficiency, reduce weight, etc.

The whole project helps the designers think outside the box, and may, if lucky, help create something inovative / new, that might benefit more mainstream helicopters.

Re:Point?

[fireman sam]

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!

Does strike me as feasible

[AKAImBatman]

A normal helicopter needs several Kilowatts of engine power to produce enough lift to even get itself off the ground, much less loaded down with a human. 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. Perhaps if the copter weighed almost nothing, and it was constructed of super-strong materials. Of course, then we'd have unobtainium. :-)

Re:Does strike me as feasible

[Kynde]

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.

Re:Does strike me as feasible

[GoofyBoy]

A human generally is lighter than a combustion engine.

Look at the Vancouver article, the helicopter looks more like a glider.

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?

Re:Does strike me as feasible

[wwest4]

I don't know where you got that figure, but you may want to look at the sustained power output of a cyclist. I am an average cyclist, and I can pump out more than 200 W sustained if it's for only a few minutes. For comparison, the Tour winner cranked out around 350 W average for the whole tour, and is capable of much more. (of course, power/weight ratio is what really counts, but the same argument applies).

Re:Does strike me as feasible

[KjetilK]

RTFWS... I have personally small problems sustaining 400 Watts over a period of a few minutes, and I can probably get somewhat higher since I have a pretty good anaerobic capacity.

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.

Re:Does strike me as feasible

[AKAImBatman]

500 watts is a lot for a human. But it's also something most humans can only do for short bursts. i.e. Your body stores up glucose for when it's needed. As long as you're stored glucose is being burned, you can reach potentially huge increases in physical power. But once the glucose fuel is exhausted, your power ratings become dependent on your body's ability to produce more glucose. This ability goes down as the lactic acid builds up in the muscles, making high levels of production that much more difficult.

Even if we assume a constant 500 watts, we're still terminally short of what would be needed for rotationally powered flight. In addition, a person capable of 500 watts would have a much higher weight, thus offsetting some of his gains. In comparison, the smallest 1 person helicopter weighs in at 254 pounds, but produces 55 horsepower! A human can't (normally) even produce 1 horsepower, and if he can it's for a VERY short period.

Now if we were to talk about powering ultralight airplanes, then I'd be a bit more optimistic.

Re:Does strike me as feasible

[rjstanford]

Hmm. When it comes to power produced on a bicycle, there's one obvious place to look...

http://www.lancearmstrong.com/faq.html 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...

Re:Does strike me as feasible

[pclminion]

So, does that mean that no energy is expended holding yourself at the top of a chinup?

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.

Re:Point?

[storl]

I'm guessing that the point of this is that a bunch of really bright (ok, maybe not so bright in this case) people are thinking of a way to solve a problem. Think about how useful a human-powered helicopter would be. Not only that, but how many failed attempts were there before the first successful airplane? Maybe someday someone will get it right, and you'll be able to pedal through the air to work. This helps people think up unusual solutions to interesting problems. Having a generation of people that are taught to think shouldn't be a bad thing in a free society.

Design vs Implementation

[sczimme]

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, ...) and assembly (see Thunderbird Projects - Picture gallery).

"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:Will someone hep me?

[Cat_Byte]

Pilot 1: "pedal faster!"
Pilot 2 (using Scotty voice): "I can't take much more cap'n!"
SMACK!
They hit each other.

What a shame

[azbot]

Wow did you see the size of the rotors on that thing?

Its a real shame that it didn't work, sounds like the team have been working on it for a long time, which makes me wonder, wheres the tail rotor?

Re:What a shame

[dykofone]

Counter-rotating rotors, a lower set goes one way (let's say clockwise) and the set above it goes the other way (let's say anti-clockwise).

The torsion created by each set of rotors balance out, preventing the need for a tail rotor to prevent spinngin. It was one of the upper rotors that hit the lower rotors in this case, which is thought to be due in part to heat and humidity (probably since the top rotors were longer, the heat and humidity caused them to bow, and they didn't generate enough lift to pull themselves out of the way of the smaller lower rotors as they lifted up).

Some more info here

Competition rules url

[Andy_R]

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.

Re:Need a stronger human

[The Infamous Grimace]

Or get MC Pee Pants to sponsor...

"I need candy!"

(tig)

Re:Point?

[dykofone]

Ah yes, "The Point," what is it and why should anything be attempted if "The Point" isn't clearly defined in a two-page, three-color brochure accompanying a 10 slide powerpoint presentation (with plenty of cute sounds and clip-art) and of course complimentary box lunches.

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.

Re:Point?

[BenjyD]

Because military applications are the only point for inventing anything, of course.
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:Point?

[Anonymous Coward]

Really, what is the point of this?

To get the prize, dipshit.

Sooner or later someone will do it.

[runner_one]

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.

Over 100 Engineers...

[D.Throttle]

and no one caught such a simple design flaw.

All they had to do was have the outer wing on the bottom.

The chain broke?

[955301]

I would suspect they would have to have gears to get the rotors up to speed but, judging from the picture, I guess they figured the pilot had enough to do, what between holding on for life, pedaling, and praying to the gods.

Re:Will someone hep me?

[erick99]

There were two rotors, one stacked above the other. The lower rotor was apparently generating lift but the upper rotor wasn't. I imaging that the lower rotor raised up a bit as it generated a net positive force on the bottom of the blade (this is how fixed wing works but I am not 100% sure that it translates to rotor) whereas the upper blade might have been sagging or simply did not lift up a bit as they might have expected.

Cheers,

Erick

Possible?

[telemonster]

Is it possible someone did the math and figured out people can't generate enough lift to keep themselves in the air (the more people you add, the heavier it gets).

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."

Re:Will someone hep me?

[D.Throttle]

The team used a counter-rotating design. The outer wing rotates clockwise and the inner wing counter-clockwise. The outer wing which is situated above the inner wing naturally flex and hangs down. It was hanging down to the point at which each wing made contact and shattered into countless pieces rendering thousands of man hours and about $30,000 worth of materials useless.

That should read average human body...

[TamMan2000]

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.

Re:That should read average human body...

[Overzeetop]

Yes, that's true. In fact, most healty indivduals can generate more than a horsepower (746W) for very short bursts. To prove this to yourself, find a flight of stairs and time yourself running up them:

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:That should read average human body...

[anethema]

Aww man, no one wants to picture that.

1000's of fat slashdotters trying to run up the stairs seeing if they can generate a horsepower of energy.

Re:Point?

[the_mad_poster]

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.

Screw the subjects... I'd be happy if we could at least get back to the point where we're not intentionally holding brighter people back or trying to keep their accomplishments covered up so we don't hurt the dumb and average people's feelings.

My easy solution...

[TheCaptain]

The weight isn't as important as a little forethought.

It has to be human powered? Fine...put Joe Powersource on it...let him peddle like mad. Store that up in a flywheel or other such reservoir. Let Joe keep peddling one more minute while you tap the flywheel to get the darn thing in the air and help hold it there for a minute.

Eh...then again, I didn't read the rules for this thing - but I'd be looking for the easiest solution the rules will allow rather than the most elegant one. You are trying to win 20k...not the nobel prize.

The art of flying...

[bsd4me]

The art of flying is learning how to throw yourself at the ground and miss.

Re:The art of flying...

[jcostantino]

Informative? That should be moderated Funny.

Re:The art of flying...

[jcostantino]

I wish I had a mod point to give you, I'd break the cycle and moderate it "insightful."

Re:The art of flying...

[tylernt]

You get no karma for Funny (which, incidentally, is a dumb move), so some mods give people other moderations to reward witticisms.

Re:The art of flying...

[loucura!]

What about balloons, don't they fly?

Re:The art of flying...

[loucura!]

I know they do, I was just being an ass, as the parent responded to himself to avoid my response.

Re:Just a question...

[dykofone]

Simplicity and weight, I would guess. Each gear in bycicle tranny weights about .6 pounds(about .3 kg, for those of you counting along anywhere else in the world).

100 of those and you've got yourself another 60 pounds you have to lift, plus the extra mounting brackets, cables, shifters, chance for breakage, etc.

Besides, having guys run in circles to get the thing up to speed brings back images of the good old days of push-start props on airplanes.

Previous attempts at such a prize

[lemonk]

I was a member of a team way back in around 1993 that was going for the Sikorski Challenge, which I believe was similar to this one. At the University of Illinois at Champaign-Urbana our project, named the X-391 Dragonfly, was to hover at 1 meter for I forget how many minutes. We got as far as building the main rotor from carbon fiber/kevlar/foam injection with a custom made oven/vacuum bag contraption as well as designing the 'cockpit' the rider would sit in. It was a great experience even if it never "got off the ground" pardon the pun.

Human Helicopters

[justanyone]

I believe the only way we could create human-powered aircraft is when the components (mostly wing area) was large and light enough to overcome thrust-drag ratios.

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:Point?

[Sebadude]

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.

Re:Point?

[Anonymous Coward]

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.

energy storage is forbidden

[bani]

its one of the rules for the competition. a big rubber band would violate the rule and disqualify them.

At least they proved...

[hcdejong]

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...

Damn

[Monkeyman334]

I guess there goes my dream of being a human powered .. helicopter ... pilot. Soaring through the ... 3-meter-sphere. Okay, nevermind.

Wait a second...

[RealErmine]

A team of University of British Columbia engineering students tried to win the $20,000 US prize offered by the American Helicopter Society.

Since when is Canada part of America?



=)

Re:Wait a second...

[Anonymous Coward]

Uhhh... Since when is "America" only the United States of America? In most parts of the world, "The Americas" stretch from the southernmost points in Chile to the northernmost parts of CANADA.

It always ticks me off when "Americans" think that "America" is the name of their country. I mean, if I were to form a country in Europe, and call it the "United States of Europe", I would have a heck of a time convincing the rest of Europe that they weren't Europeans, and they could no longer be part of "Europe" since that was now the most obvious short form of my new country. Unfortunately the world has allowed the United States of America to do just this. Of course, I can intentionally annoy the USA and be safe because I know I don't have any WMDs... wait a minute...

Re:Wait a second...

[JCholewa]

> What word do you suggest replacing the "American" in "I am American"
> (don't reply with some smartass answer either)?

How about "a US citizen"?

blades not stiff enough?

[mks180]

"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.

can't be all that bad...

[bani]

...russians are rather fond of using the dual counterrotating design.

http://www.airliners.net/open.file?id=056899
ht tp://www.airliners.net/open.file?id=123084
http:/ /www.aeronautics.ru/kamov/ka5201.jpg
http://www.a eronautics.ru/archive/vvs/ka27-01.htm
http://www. zap16.com/mil%20fact/kamov%20Ka-50.htm

Re:Just a question...

[YrWrstNtmr]

Because it takes the same amount of energy to lift ~200lbs straightt up into the air, whether the riders legs are going 30RPM or 200RPM.

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.

Re:Just a question...

[TigerNut]

The aerodynamic drag induced by trying to spin rotors at high speed would keep you from just continually accelerating the blades, just like you can't automatically go faster on a bike by putting on extra gears or steeper ones.

Human combustion is still a risk

[Anonymous Coward]

not getting off the ground makes it difficult to crash

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 ...

Crazy

[PingPongBoy]

Two rotors? The blades are so big the drag will make it really hard just to sustain RPMs. If the rotors have independent speeds of course they will smack each other given they are nearly in the same plane.

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

Re:Point?

[Tanktalus]

You obviously haven't heard about the Canadian Army's Sea King helicopters which cost $000's per day to maintain. With a human-powered helicopter, Canada could cheaply replace all of its dozen or so copters with these, and gain more maneuverability, speed, and reliability! Even if the thing never leaves the ground...

Re:Will someone hep me?

[pclminion]

Did you read the article?

"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?

That is how they did...

[Gordonjcp]

... the first human-powered cross-Channel flight. I know one of the guys who was on the support boat for it, and who was heavily involved with the project. They figured it was easier to get a cyclist and teach them to fly an aircraft, than to get a pilot and train them up as a champion cyclist.

You know

[Andy Dodd]

I believe they nearly got rid if the gifted/talented (In elementary/middle school) and Honors programs at my high school because of just such complaints from parents of those kids who didn't get in.

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:Huge Glaring Problem.

[aculeus]

Actally, every helicopter pilot is taught how to land if their engine fails. As long as the helicopter is 100 feet off the ground or going faster than 30 mph, even with catastrophic engine failure, it can still land. It is called autorotation

Re:How about bulking the pilot up with steroids?

[Deeper Thought]

Use of drugs is prohibited by the 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.