es the direction in which the machine has its life,-its moving principle. Planes have their fascinati

. We have nothing to do here with the construction and operation

e directly to the point to consider the follo

nt of power

lculate the

s mou

ain calculations must be made to determine what is required. A horse power mean

er of the roadway is understood, it is a comparatively easy matter to calculate just how m

ems may be known in a general way, the aviator has several unknow

is the propeller pull. The energy of a motor, when put into a propelle

ot Pounds. If 550 pounds should be lifted, or pulled, one foo

nds, a distance of one foot within one second of time, and we have

ness of the air, and its great elasticity; and, second, the difficulty of making a sur

be made available, in a medium as elusive as air, the least change, or for

ion of the propeller, up to a certain point, beyond which the pull decreases in proportion to the speed.

e it cannot exert the proper energy; if the pitch is very small then it must turn further to get the sa

as we now know it, is anything like the true or u

e place in aerial navigation, and if it were possible to get only a quarter of the effective pull of an engine,

man has done. Calculations made with birds as samples, show that many of them are able to fly with such a small amoun

osition or arrangement of the planes with relation to th

ace of 300 square feet which weighs 900 pou

h an airship under those conditions. It may be propelled through the air t

es an hour, would require an additional power in doing so,

ds for each horse power, due to the slow speed of the propeller, and also owing

certain point the pull of the propeller increases; but beyond that the vacuum behind the blades becomes so great as to bring down the

bite of the propeller on the air would be ineffective, hence it will be seen that it is not the amount of power in itself, that determi

d to effect a launching. In that case the propeller must be made so that its greatest pull will be at a s

accretion of power adds to its speed. In flying machines the aviato

a plane at an angle of forty-five degrees, to which two scales were attached, on

e angle of the planes is forty-five degrees. If we suppose that the air beneath the plane is a solid, and frictionless,

force, in moving downwardly, along the

y-projecting cord represents the power, or propeller pull, which must, therefore, ex

ne E would be 900 pounds, being the composition

drawn forwardly, in the line of D, if we had a propeller drawing along that line, which has a pull of 450 pounds, it wo

izontal and

determining this factor, and we refer to the chapter on that

mounting, than in any other direction. This is especially true where two propellers are used,

to fix it securely. The vibratory character of the mounting makes this a matter of first importance. If there is a solid base a

ed would cause a loss of from ten to fifteen per cent. in the pull of the pro

insecure attachment of the propeller to the shaft; second, the liability of the base to weave; or p

of a propeller, it would not be so important to consider the matter of vibration; but the propeller, if permitted

s have been registered by bolts which have come loose from excessive vibration. It is well, therefore, to have each individual nut secured, or properly locked, which is a

t, before help arrived. There is no excuse for such dangers. Most of such accidents were due to the old practice of making the tanks of excee

, as this metal will not readily rupture

cement overhead argue that in case of an accident the aeroplane is likely to overturn, and the tank will, therefore, be below the pilo

ine. Many have had accidents where the machine landed right side up, even where the fall was from a great height,

from its position, when the ship strikes the earth, because in

ed toward the tail end of the machine, a place of safety for two reasons: First, it is out of the reach of any possibl

even disarranged, and in many of them, while the entire fore body and planes were crushed to

nd the adding of the weight of the gasoline would be placing but little additional duty

nt, which has had the effect of giving greater security to

in the starting of the machine. The power is usually so mounted that the pil

lutch, makes it necessary, while on the ground, for the propeller to be started by

ight luxuries that all have been trying to avoid. Self starters are readily provided, and this with the p

r must be devised which will enable the pilot to change the pitch, as the speed increases, and t

time, and the real improvement would be in the direction of having the blades capable of automatic adjustmen