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Gamera II Team Smashes Previous Best Human-Powered Helicopter Flight Time
Zothecula writes "For over 30 years, the $250,000 for the American Helicopter Society's Igor I. Sikorsky Human Powered Helicopter Competition prize has looked decidedly secure, but Gamera II has changed all that. Last week, Clark School of Engineering team pilots came close to breaking one of the competition's major milestones. Ph.D. candidate from Kyle Gluesenkamp from the School's mechanical engineering department, hand-cranking and pedaling like his life depended on it, managed to keep the huge quad-rotor craft aloft for 50 seconds, an impressive new world record that's currently awaiting validation by the National Aeronautic Association (NAA)." We previously covered their attempt to break the record last May.
Gamera is REALLY NEAT.
Gamera is FULL OF MEAT.
We all love you, GAMERA!
Although the summary doesn't state it, the Clark School of Engineering is part of the University of Maryland at College Park.
Seems to me they could break 1 minute easily with a better cyclist and maybe better gearing ratios?
Until then, have a look at the following video of Gluesenkamp's awe-inspiring record flight
I'm sorry, I didn't even realize he had lifted off the ground. Awe-inspiring isn't exactly the word I'd use.
That would basically render the whole exercise pointless, because any energy-storage device on-board the craft could be powered by any form of energy. For instance, if you could build a giant 8-seat helicopter and power it with electric batteries, then even a human could "power" it by using an exercise bike to charge the batteries, very slowly, over the course of days or months. I think the whole idea is to make a craft that's so light that a human can power it directly; by storing energy, you can make the craft as big and heavy as you want.
MILLIONS of FLIES!!
Realistically it is an interesting exercise (pun intended) in efficient design. Real question is: for a 100% efficient design, of zero mass, how long can the best (i.e., well doped) cyclist in the world stay aloft?
No. The rules http://www.vtol.org/awards-and-contests/human-powered-helicopter/hph-rules (Rule 4.1.4) say that you can not use any form of stored energy. They exclude the rotors, of course.
I wonder if you could just beat the record by getting a real cyclist on the thing. Put one of those Olympic or TdF cyclists on the thing. They probably wouldn't even have to use their arms. You could probably design a helicopter with 2 people powering the helicopter. If one person can lift their own weight plus the weight of the craft, then 2 people could distribute the weight of the craft between them. So long as you didn't need too much extra parts to make up for the extra complexity of 2 (or more) riders. Definitely a lot of room for improvement and breaking this new record.
Anthropic principle: We see the universe the way it is because if it were different we would not be here to see it.
A somewhat more practical device could be a hydrid airship/helicopter. Keep it heavier than air, but use a hydrogen-filled balloon to counter most of the weight and cycle power to carry the rest. Unfortunately, it would still be large, but the helicopter part could be substantially smaller.
They're taking massive advantage of ground effect, and are using the distributed rotors to magnify the effect more than a single rotor could. That's probably the primary reason they did so well.
The entire thing seems to be an exercise in futility. Helicopters aren't very efficient. I'd be much more interested in seeing more of the human-powered-glider competitions. Those guys can keep them up in the air quite a lot longer.
I work for the Department of Redundancy Department.
Is it a helicopter or just using ground effect? I mean could it fly higher?
The device in question does appear to be designed specifically to maximize the use of ground effect. The whole machine looks like it's upside-down to get the rotors as close to the floor as possible. However, just because it was designed to use ground effect, doesn't mean it isn't a helicopter. I consider it a helicopter, just not a very practical one.
Kudos to the designer for taking every possible advantage to break the record!
One of our competitors trademarked the term "hypothesis". From now on, we will call them "boneheaded ideas".
That's 2 posts about Contador in this article already. Sure he has plenty of allegations against him, but the whole sport is pretty much run off drugs. He was just caught.
Anthropic principle: We see the universe the way it is because if it were different we would not be here to see it.
A bit too solid, and the angles are all wrong (for the rider).
Putting the rider in a reclined position, he's unable to use his body weight against the pedals. Using his arms,he's unable to brace his body to use the full power of his legs (by far more powerful than arms), and by using fixed gearing - the cyclist and the craft reaches max-rpm quickly. Adding gearing would allow the rider to get the rotors spinning with relative ease, then increase the rpm of the rotors by switching gears.
I say:
1. eliminate hand pedaling
2. put the rider upright
3. make it an 18 speed
"Lame" - Galaxar
That's a good question. However, as an engineer, I feel obliged to point out that this exercise, while interesting, has absolutely zero practicality or usefulness. Even if you could reduce the helicopter's mass to zero, the amount of energy a human would have to expend to keep himself aloft is staggering. Obviously, a fit human can do it for a minute or three, an athlete like Lance Armstrong might be able to keep it up for 5-10, but that's it; after that, they'll be crashing.
Not only that, this test isn't very realistic as far as helicopters are concerned: they're not far enough away from the ground. Close to the ground, you get the in-ground hover effect, which reduces the amount of power you need to stay aloft. Over 10 feet or so, you go into out-of-ground effect, and then your power requirements increase significantly. In-ground effect is only useful for taxiing to your runway or helipad; if you want to hover anywhere else, you're generally doing it out-of-ground. So even a fit human will have a much harder time keeping that up for long, even with a zero-mass machine. There's a reason birds have hollow bones, and why even hummingbirds (which hover rather than glide) have very limited flight durations, despite their tiny size and mass.
That's a good question. However, as an engineer, I feel obliged to point out that this exercise, while interesting, has absolutely zero practicality or usefulness. Even if you could reduce the helicopter's mass to zero, the amount of energy a human would have to expend to keep himself aloft is staggering. Obviously, a fit human can do it for a minute or three, an athlete like Lance Armstrong might be able to keep it up for 5-10, but that's it; after that, they'll be crashing.
Also, it doesn't involve spherical cows in a vacuum.
...si hoc legere nimium eruditionis habes...
Busted on Mythbusters; the paint used to seal the canvas had the wrong proportions, and did not have the same burn rate as rocket fuel. The paints were also layered, and at least one of those layers was fairly fire retardant. If you watch the episode on the Hindenburg, you'll see they did a number of large-scale models, and it really was the hydrogen that caused part of the issue (ANY skin that is at all burnable will cause the same effect when the volume of hydrogen gets large enough). In small-scale, hydrogen just burns "up" -- and quickly, with an almost invisible flame. This doesn't scale, however.
Short story is: it's possible to use hydrogen in an airship if you use the right fireproof materials for structure and envelope -- but it's still going to cause a large fireball if it starts leaking and is exposed to flame (oxygen is also needed, so as long as it's sealed, sparks inside the envelope shouldn't be a big problem).