Rules of Flight

EamonnKeane

I was just wondering what laws (physics, biology) govern whether an animal can fly or not. How much lift would mechanical wings need to make a human fly? It can't be that humans are too heavy because the dinosaur Quetzalcoatlus had a 10m wingspan and weighed over 60kg, and it could fly. Are human bodies too dense compared to birds, or would mechanical flapping wings add too much weight? Just something I was thinking of.

Capt'n Midnight

IIRC the O2 level back then was about 5% higher so a bit more lift and a lot easier for the cardiovascular system to keep the muscles supplied with oxygen.

Keyword - Ornithopter

John

Human bodies aren't aerodynamic for one thing. For another the muscles of the chest and back aren't big and strong enought to power wings.

EamonnKeane

I was talking about wings that flapped themselves using some kind of motor...

Pataman

Am I right in saying that birds bones are hollow, to make them lighter?

DrIndy

Pataman wrote:

Am I right in saying that birds bones are hollow, to make them lighter?

Birds bones are in fact honeycombed to make them extremely light and strong. However, they also are difficult to heal when broken....

Their physiology is also designed differently, do you notice birds don't pee? In fact their urine is the white stuff around the crap, this is to reduce the need to carry extra water which would slow a bird down in flight......

Celticfire

EamonnKeane wrote:

I was talking about wings that flapped themselves using some kind of motor...

I think some of therse guys tried various ways to get in the air.........http://invention.psychology.msstate.edu/i/Chanute/library/Prog_Illustrations.html

John

DrIndy wrote:

Their physiology is also designed differently, do you notice birds don't pee? In fact their urine is the white stuff around the crap, this is to reduce the need to carry extra water which would slow a bird down in flight......

If ever you're holding a bird in your hand and it ****s on you you'll notice it's actually a paste and a liquid. They don't synthesis urea, their kidneys are different to ours and make uric acid instead.

Interesting fact: chicken is white meat because white muscle is best for short bursts of energy (short flight away from a predator) whereas duck is red meat as it is slow release energy-wise and allows for flight over long distances.

EamonnKeane wrote:

I was talking about wings that flapped themselves using some kind of motor...

Sorry, back to your original question. I think not only would mechanical wings be too heavy but the human body is too heavy and not aerodynamic enough for wings to have any effective lift. The closest you'll get is hang gliding.

EamonnKeane

It's not too heavy: Quetzalcoatlus (below) was 60 kilos. And an aerodynamic suit could be worn without adding much weight.

John

The human body IS too heavy for its shape. Look at Quetzalcoatlus, it is nearly flat and apart from its wings it is shaped like a dart. The weight is distributed in a manner that is more suited to flight. Short of reconstructive surgery there is not much that can be done to:

(a) redistribute weight in the human body (the head weighs an awful lot thanks to the brain)

(b) make the body properly aerodynamic. A suit may cut down on some wind resistance but not enough to allow actual flight. If you look at olympic cyclists and their aerodynamic helmets and drag resistant suits you can see that the body is still not aerodynamic for flight.