h a l f b a k e r y"This may be bollocks, but it's lovely bollocks."
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Human-powered flight is now an established technology.
One exponent has even succeeded in carrying a passenger.
But so far, there seem to be no multi-person-powered examples.
This is odd, because the economies of scale apply equally well to all aircraft.
For example, a three-person craft
could have the same frontal cross-section and still wouldn't need to have an airfoil of three times the area; it would need to be bigger, and the fuselage would be somewhat heavier, but it's not a linear relationship. Similarly, the propeller could be almost the same size and mass, even though fed with three times as much power.
Crowd-powered flight; an idea whos time has come.
[link]
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"You toss me off this airplane, and you are all going
down!" |
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Inspired by recent UAL news story. |
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I wonder how many people will be needed on the first
human powered airplane to circumnavigate the globe non-
stop. |
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Assume that a fit human can pedal at max output for one hour in every eight, with seven hours recovery. |
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So the aircraft has to be capable of carrying 87% "deadweight" in terms of power, representing the resting humans. |
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Many wide-bodied aircraft can carry 320 humans, so could 40 humans provide enough power to lift themselves and the other 280 ? |
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The aircraft will be low speed, perhaps 20 knots; your planet is about 24000 miles around the equator. That's 1200 flight hours, assuming no adverse winds - 50 days. Now, given that the humans are exerting at maximum levels, an allowance of 5 litres of water per person per day is not unreasonable. That's 80,000 litres, or 80 tonnes. Some might be recycled, perhaps using a solar still, but a lot will be lost by respiration and sweating. Water could also be collected by condensation from the atmosphere, but it would have to be an energy-neutral process using ultra-lightweight equipment. |
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So, could 40 humans sustain an airframe, 80 tons of water, and 20 tonnes of other humans, in flight at a steady 20 knots, for two months ? |
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The figures don't look encouraging. |
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Yes, but if you scale it up (1000 people, correspondingly large aircraft) it becomes feasible, should anyone wish to fease it. |
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Is there a first class section on this flight? |
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Single-seated, pedal-powered planes weigh half-a human or less, in comparison to the average car, which weights about a dozen men, or more. You're not getting THAT much extra economy by adding another seat to a pedal-plane as you would by carpooling. |
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Not sure what your point is. |
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Solo human aircraft - 1.5 x mass of human. |
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But a 2-person aircraft isn't going to be 3 x mass, probably only 2.75, so doubling the available power doesn't double the all-up takeoff weight. |
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There's probably an optimum point, beyond which the extra power is all being used to compensate for increasing drag, becasuse the fuselage and wing area are increasing, altho because of square-cube volumetric relationships the larger fuselage will contribute less to the overall increase in cross-section; but the Law of Diminishing Returns always gets you in the end. |
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The limiting factor is probably related to the strength of materials that make up the airfoil. |
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//but the Law of Diminishing Returns always gets you in the end.// |
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Au contraire. The more people, the better the returns. The curve never levels off, at least until you reach the point where parts of the plane are poking out of the atmosphere. |
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// Assume that a fit human can pedal at max
output for one hour in every eight, with seven
hours recovery. // |
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I suspect that you can get higher average power
from each person if they are working at a greatly
reduced level for a higher percentage of the time.
I started trying to put some numbers together to
defend that assertion, but I got bored... |
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Food and water requirements are a very valid
point. The first team to accomplish this will
probably need to "cheat" using in-air "refueling". |
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Circumnavigation is a very long term goal. A closer
milestone might be something like an 8 hour flight
with 3 people that would be completely impossible
with only 1. |
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// I started trying to put some numbers together to defend that assertion, but I got bored... // |
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