hat power is the true secret of aeroplane flight, it is desira

called "skippers." He has noticed that if they are particularly thin, and large in diameter, that ther

s slow it will quickly wend its way to the earth in a gradual curve. This curved line is called its trajectory. If it is not very large

round ball, or an object not flattened out, will m

element which accounts for it. Such being the case it may be well to inquire into the peculiar action which causes

ct of air against a moving body does not increase in proport

16; 5 X 5 = 25; and so on, so that 16 is the square of 4, and 25 the square of 5. It has been found that a wind m

pushing force is not 4 pounds, but 8 pounds. If the speed

wer it goes through the air in such a way that its fiat surface is

s it, and does not in any way depend on the air to hold it up. See Fig. 1,

A Skipper

ribing the line C, Fig. 1, the disk B, in this case descending, without changing its position, whi

not be horizontal. Instead it assumes the position as indicated at D, and this impinging effect against the air causes the skipper to move upwardly along the line E, and having reached a certain limit, as at, say E, it

n a plane surface, and that the extent of the action, to su

or surface, and that for gliding purposes speed may be sacr

here the power of the engine is cut off, either by accident, or designedly, and the

at an angle, or downwardly, and thus enable the pilot to sail to another point beyond where he may safely land. This changing the

stance, an aeroplane is moving through the air with the front margin of the planes higher than their rear margins, it is said to have the

d it will be seen, therefore, that the angle of incidence means

urface, bear an intimate relation with each other, it may be understoo

do so only by moving through the atmosphere rapidly, or by having a large wing spread relative to the weight. It will thus be seen that speed and surface become t

t, produced by power expressed in some form, is the sole and most necessar

is of no consequence; shape need not be considered, and an

hrough space by force alone, is a different matter. To change the machine from a str

self. Now, in order that there may be a change imparted to a moving mass, a

ther fore or aft of the machine, or at both ends, the angles of inciden

to keep it in motion horizontally, at all times, aeroplanes are provided with supporti

trol from side to side is not dependent on the power of th

es, are the only factors to be considered, and these