Ultralight pedal-powered aircraft... the way of the future?

Question

I was thinking... I don't know if this has been invented... Bicycle plane. Pedal, a high-geared prop spins rapidly, the bike accelerates, takes off. What I want to know, before I begin welding, how wide should the wingspan be for easiest takeoff without exceeding two highway lanes wide? Made from aluminum, for it's lightness. How fast do you think it will go? Lastly, how can I protect myself from the wind, etc.?

Answer 1

as above - a better link is "human powered aircraft" with more history

http://en.wikipedia.org/wiki/Human_power...

Unless you're filthy rich, I'd wager you don't have access to the materials required to make a successful attempt.

Answer 2

its been done already... dont have a site  but its pretty cool .. was done in the late 80's or early 90's.. they crossed the english channel

Answer 3

A lovely idea, but the problem is power.

You don't make enough power to keep yourself in flight.

The human powered plane that flew the English channel made it with great difficulty, and a bicycle champion was at the pedals. It would be utterly impractical for human beings of normal shape and size.

***

A "high gear ratio"prop still needs POWER to spin it at high speed.

Do you honestly think airplane manufacturers would design huge engines with incredible power that drink huge amounts of jet fuel, if they could put a hamster in a wheel and gear it differently?

Why do you think you can't put your ten-speed bike in high gear and go up hills?

Answer 4

It has been invented.

Several years ago someone made a small pedal aircraft. It was basically a super light glider with a very small cockpit area that housed a bicycle that was used to power the prop.  I'm sure you could find lots of information on it, It crossed the English Channel in the mid 90's, I want to say 97 but I'm really not too sure on that.

It took many different models before they found one that worked, and once they found one that worked it took an elite cyclist to power it. You have to consider, most people can't generate much more than 1/3 of a horse power, thats nothing! A small remote control airplane engine can do that, and do it as long as it has fuel. We get tired and have to slow down. If it takes every once of strength of a world class cyclist has to power an airplane that is super light and has no room for so much as a small radio, much less a bag of groceries, how would it ever be a valid form of transportation for the masses?

Its a great idea, don't let me take away from your idea! and you can do it, if it were made entirely out of carbon fiber, titanium, and other super light materials it could be done. Maybe you could use a small, light weight engine to supplement your leg power. That will be expensive, but it has worked so it can work again.  As for the way of the future, I just don't see it happening.  

*EDIT*  I realize how a high gear ratio will help you some, but look at riding a normal bicycle. If you put it in the highest gear you have doesn't it take a lot of effort to pedal? I don't know about you, but for me I almost never use the highest gear on my bike just because there are more efficient gears that better suit the speed I want to go, with the strength I have in my legs. Higher gear ratios are not the answer. A lower gear ratio with a more aggressive prop would probably do more good. Thats a trial and error thing. But I can assure you that the two aircraft aviophage spoke of used gears to achieve an optimal prop rpm.  If you have access to super light weight materials and the tools needed to make a wing, and either you are, or you know someone who is a world class cyclist then you can do it! But its not something the average person can do.

Answer 5

Yes, it's been done.  It was a successful experiment, but part of the success is that it proved that a human powered aircraft, while possible, is not practical.  It cannot lift an average person, but only someone light, wiry, and exceptionally well conditioned.

The first airplane was called the Gossamer Condor, and its successor, the Gossamer Albatross, crossed the English Channel in 1979.  Both aircraft are preserved at the Smithsonian Air and Space Museum in Washington, DC.

These aircraft had wingspans of about 100 feet and weighed around 70 pounds.  This obviously means that the aircraft were made out of extremely light materials and were very fragile.  You would not be able to fly on anything but the very calmest day.  And you would have to be in Tour de France physical condition and weigh about 110 pounds or less.

The average person does not have access to the kind of materials and methods that were required to build these two aircraft.  It would cost more to create the workshop than to build the airplane.

To get an idea of what these two aircraft were like, do an internet search on "gossamer condor" and "gossamer albatross."

Answer 6

As other answers have made clear, the problem is power—human beings don't produce enough of it, and what they produce can't be efficiently translated into thrust.

An aircraft needs power for two things: going forward and going up. It's the going-up part that presents a problem.  To get to an altitude of 1000 feet, for example, the bare minimum energy you must produce is equivalent to climbing the same distance—which is the equivalent of a 100-story building.  Never mind about getting to 3000 or 5000 feet.  And the air gets thinner as you climb, so you have less and less oxygen to power yourself at a time when you need a great deal just to stay aloft.

You don't need much energy to go forward or to glide. Unpowered gliders prove this all the time, and they can fly for hundreds of miles.  But something has to hoist you up into the air in the first place, and in a human-powered aircraft, that something is you.

Birds manage this because they are extremely light and are very specifically designed to fly with maximum efficiency.  Even so, they use a lot of energy for their size.  Large birds can glide for hours, but they still consume a ton of energy to get up to altitude in the first place.

In short, it's just not practical. The energy required to continuously fight gravity and induced drag, especially when climbing, is just too great.  I think it's safe to say that this is true for all land-based animals, not just human beings.

Answer 7

Because the drag of the prop would be so great, you wouldn't be able to generate the power - try starting off in top gear on a 10-speed bicycle, you realize how hard it is to get going at all...same thing with a prop. You THINK you can spin it fast, but it doesn't work that way. The air friction would wear you out in a few seconds, and you'd stop pedaling. U CAN'T DO IT...if it were possible, it'd have been invented and DONE already, long ago. THink of something else, genius.

- The Gremlin Guy -