"When is flight possible without wings?"
Maygan, I think you need to re-asses your question, flight and fly are defined by OED (ish) as:
Flight
1 a : an act or instance of passing through the air by the use of wings b : the ability to fly
2 a : a passing through the air or through space outside the earth's atmosphere b : the distance covered in such a flight c : swift movement
3 a : a trip made by or in an airplane or spacecraft b : a scheduled airplane trip
and
Fly
1 a : to move in or pass through the air with wings b : to move through the air or before the wind or through outer space c : to float, wave, or soar in the air
So to revisit your original question again taking this into account then;
If you mean can a man remain unsuspended using his own power to remain aloft without resource to technology, then the answer is (as yet) no. For a man to beat his arms like a bird (apart fom the whole feathers/flight surfaces thing) he would require pec muscles to be in excess of 6ft across (BTW Birds reduce their power requirements by having hollow bones.)
If you mean can a man describe a trajectory through the air with little or no control, then that is feasible, human canonball is one way. There is an Amercian guy who has a winged jumpsuit which allows him to jump out of a plane and glide forward, but it doesn't provide enough upward lift to be classed as flying as he is still describing a downward trajectory, and ultimately has to resort to parachute for a safe landing.
A basketball player is describing a trajectory and is not actually in the real definition of the word, flying.
The difference is that flight is the ability to change course, direction and altitude with control at will. However a trajectory is prescribed before hand by several factors; Gravity, the energy and mass of the object, the medium through which it is travelling (the greater the altitude the less 'thick' the atmosphere so the same amount of energy at the objects drag coeffient.
Further once a tracetory has started the only way to change it is either;
A) Apply an external force to the object, by either hitting it with something or placing something in its path for it to bounce off.
Or,
B) Create thrust from inside he object, again Newtons first law applies here.
So could somone be shot out of a canon then turn 90 degrees and go in another direction? Then no, not unless they had a rocket pack strapped to them to provide vectored thrust and thus change direction.
Which brings me back to my earlier assertion that flight without wings could be feasible with rocketry or jet engines. Helicopters don't count as there blades have a wing cross section and are classed as non fixed wing aircraft.
Oh, but brainwave, Hovercraft is techically a flying vehicle (albeit only a few inches off the ground) it doesn't use wings it uses ducted fans to provide thrust. Helium or Hydrogen in a balloon is of course another possibility. But these all use technology to provide the upward thrust needed.
So I'm afraid if you want to know can a man "Fly" then sadly no. But it doesn't stop me dreaming of it!
P.S. Watch Superman The Movie and acording to the strapline "You will believe that a man can fly" (which I always thought was wrong because surely it should be "You will believe that only Superman can fly, well jump very high actually but we thought flying would be better for the movie". |
