The Aeronautical Annual, Volum 1James Means W.B. Clarke & Company, 1894 |
Altres edicions - Mostra-ho tot
Frases i termes més freqüents
action aerial machine aerial navigation aerocurves aeronaut aeroplanes altitude angle art of flying artificial flying ascend back edges balloon blade body bracings captive balloon carry Castra cause centre of gravity condor considerable constructed degree descending direction downward effect engine exertion experiment extended feathers feet per second flight of birds Flying Machines flying-machine forward give hinge horizontal humming bird inches inclined kite length LEONARDO DA VINCI MANGONEL means mechanical miles per hour momentum move nature nearly oblique observations Octave Chanute Otto Lilienthal pair of wings parachute perpendicular plane portion pounds principle projectile motion propelling power purpose raising rapid ratio represented resistance sail Samuel Pierpont Langley screw shaft side Simoïs SIR GEORGE CAYLEY soaring machine soaring-machine specific gravity speed square feet strength stroke strong sufficient surface sustaining tail tion treatise upward velocity vertical waft weight wind
Passatges populars
Pàgina 118 - Five thousand balloons, capable of raising two men each, could not cost more than five ships of the line ; and where is the prince who can afford so to cover his country with troops for its defence, as that ten thousand men descending from the clouds might not in many places do an infinite deal of mischief, before a force could be brought together to repel them...
Pàgina 20 - The whole problem is confined within these limits, viz. to make a surface support a given weight by the application of power to the resistance of air.
Pàgina 55 - There be three things which are too wonderful for me, yea, four which I know not: The way of an eagle in the air; the way of a serpent upon a rock; the way of a ship in the midst of the sea; and the way of a man with a maid.
Pàgina 130 - The force to keep up the momentum of a body moving in a horizontal plane in the air (in which there is so little friction) cannot be great, and this force is all that is wanted. The movement of the neck and body of the condor, we must suppose, is sufficient for this. However this may be, it is truly wonderful and beautiful to see so great a bird, hour after hour, without any apparent exertion, wheeling and gliding] over mountain and river.
Pàgina 130 - I do not recollect ever having seen one of these birds flap its wings. Near Lima I watched several for nearly half an hour without once taking off my eyes ; they moved in large curves, sweeping in circles, descending and ascending without giving a single flap.
Pàgina 106 - Having remarked how thin a stratum of air is displaced beneath the wings of a bird in rapid flight, it follows that in order to obtain the necessary length of plane for supporting heavy weights, the surfaces may be superposed, or placed in parallel rows, with an interval between them. A dozen pelicans may fly one above the other without mutual impediment, as if framed together ; and it is thus shown how two hundredweight may be supported in a transverse distance of only ten feet.
Pàgina 130 - In the case of any bird soaring, its motion must be sufficiently rapid, so that the action of the inclined surface of its body on the atmosphere may counterbalance its gravity. The force to keep up the momentum of a body moving in a horizontal plane in the air (in which there is so little friction) cannot be great, and this force is all that is wanted.
Pàgina 48 - It has been found by experiment that the shape of the hinder part of the spindle is of as much importance as that of the front in diminishing resistance.
Pàgina 17 - I feel perfectly confident, however, that this noble art will soon be brought home to man's general convenience, and that we shall be able to transport ourselves and families, and their goods and chattels, more securely by air than by water, and with a velocity of from 20 to 100 miles per hour.