It is the direction in which most of the energy has been expended in develo

or the curved formation of the plane, have been considered in all their

, that a narrow plane, fore and aft, produces a greater lift than a wide one, so that, assuming the plane has

be projected through the air with the long margin forwardly. Its sustaining po

ft, and this may be more clearly understood by examining the illustration

eam lines al

in. For convenience seven stream lines of air are shown, which contact with this inclined surface. The first line 1, after

r, the last lines, near the lower end, being, therefore, at such angles, and contacting with such a rapidly-moving column, that it produces but little lift in comparison with the 1st, 2d and 3d stream lines. The

ear its upper end, probably near the line 3, so that the greater po

he effect produced on the upper side of the plane, over which a rarefied area is formed at c

condition of the atmosphere which has less than the normal pressure or quan

of it. This is a condition which is normally found in the atmosphere. Several thing

pwardly, to be replaced by a colder body of air. In aeronautics neither of these co

ght about by this means. If, for instance, a plane is held horizontally and allowed to fall toward the earth, it will be retarded by

ression. This may be proven by compressing air in a long pipe, and noting the differe

a rarefied area is formed on the side which is oppo

large and effective area it will add grea

in this particular, as the stream line flows down along t

es on the upper

aved plane formation, and for purposes of comparison the diagram, Fig. 2

e a little less angle of impact than the corresponding lines in the straight plane, the last line

sure somewhere between the lines 3 and 4, and the lift being thu

the plane where the air acts with the greatest force. It has refere

ines below a c

er important advantage, as it utilizes the rarefied area which

nd so curved, with relation to the forward movement, that the air, in rushing past the upper end

which serves as a lifting force, as well

stant. It changes with the angle of the plane, but the range i

lines above a

ard end of the plane than with a greater positive angle of incidence, as in Fig. 27, and when the

be faithfully copied, it is believed by many that a plane with a pronoun

ave designed types of wings whi

ging centers

ird-wing

it" the air, forgetting, apparently, that in other parts of

rcibly drive the air column apart, because the bird wing is so made, and that while it may not appear exactly l

e, called the (pectoral), has a heavy duty to perform. It is so constructed that it must withstand an extraordinary t

in joint, where the rear margin of the wing is attached to the leg of the animal, thus

ng that when the entire wing support is thrown upon the primary bone it must be large enough to enable it to car

bat, and it made a mistake in the housefly's wing which h

gin, as at A, so that when the plane is at an angle of about 22 degrees, a horizontal line, as B, passing back from t

e of the Mo

he soaring, but to the class which depends on flapping wings, and as such it canno

re cited to show how wildly the imaginati

tional means, which is supplied in the tail of the machine, just as the tail of a kite serves