Mr. Fred. W. Brearey has been the honorary secretary of the
Aeronautical Society of Great Britain ever since its establishment in
1866. In the course of his experiments, extending over some years, he
found that if a serpentine action were imparted to a fabric it would
propel an attached object many times its weight in the air. He records
in his published magazine articles that he took the idea from watching
the movements of a skate in an aquarium, which in swimming undulated
its whole body.
[Illustration: BREAREY'S FLYING MACHINE.]
In applying the principle to locomotion in air, it is of course
impossible to undulate what may called the backbone of the whole
structure in the manner of the skate. But a fabric may be so attached
to a receptacle, and so worked from thence by a suitable motive power,
that its undulations will propel and support a considerable weight,
depending upon the energy with which such fabric is thrown into waves.
He believes that the awning of a vessel can be made in this way to
contribute to a ship's progress at the same time that it would cool the
passengers.
Mr. Brearey argues that the instinct of the bird enables it to
adapt itself instantaneously to varying circumstances; that in any
arrangement for effecting flight by machinery--the adjustment of
parts to meet sudden requirements being a matter requiring momentary
thought--it is desirable, if practicable, to employ large surfaces
for parachutic action, at the same time making this means of safety
not an incumbrance, but an aid. The possession of instinct allows of
the employment of the smallest surface in proportion to weight; the
possession of forethought renders it necessary that intermittent action
shall be safeguarded by large surfaces.
This requirement is fully met, the inventor says, by the arrangement
advocated by him, and none but edge resistance is offered to the air,
except the sharp lines of the necessary vehicle. The manufacture of
such an apparatus upon a scale of utility would be as follows:
A flat-bottomed receptacle, somewhat of boat shape, would be fixed
upon wheels. At the fore part of the boat a motor would from each side
elevate and depress two wing-arms, each 15 ft. long. (See Figure.)
Along the wing-arms is attached a fabric which would form the front
part of a kite, which, being fastened in the center to the edge of
the boat, would continue for 15 ft. to the rear, being extended about
6 ft. farther than the stern of the boat by a continuing spar. To a
cross piece here would be fastened the tail end of the kite, which,
however, instead of a point, would be about 5 ft. in width. From this
again would extend a tail of about 12 ft., to which either a lateral,
twisting, or a vertical movement could be imparted by cords in the
hands of the operator in the boat for steering purposes. From the fore
part of the boat would extend a bowsprit, from which cords would be
attached to the two wing-arms to prevent the weight of the fabric from
dragging them backward.
An important arrangement has been adopted by the inventor, which he
calls the pectoral cord, which by its automatic action assumes the
functions of the pectoral muscle of the bird. This is an India-rubber
cord. It is attached by its two extremities to the under portion of
each wing-arm, and in models passes underneath a central shaft--in
this case the boat. Its degree of elasticity is regulated by the
weight. When any model with wings is committed to the action of the
air, the pressure of the air causes the wings to fly upward, and power
is required according to the weight sustained to depress the wings
against the weight. The strength of the cord, however, is such that it
maintains the outstretched wings at that angle which is suitable for
gliding upon the air without, in the case of the bird, any enforced
muscular exertion. The contraction of this cord assists the power
exerted in the downward stroke.
The wing arms would not be rigid throughout their length. They would
consist of a number of rattans or canes firmly bound together by close
wrapping, and tapered by cutting off one at intervals, this being
practically unbreakable by any accident likely to occur. The portion
next to the body for 5 ft. or 6 ft. might be stiffened by a steel tube,
forming the center round which the rattans are wrapped. By this method
of forming the wing-arms their length may be increased at pleasure.
A small model upon this principle, but without any motive power, was
liberated as an experiment by Captain Templer, from a balloon which had
risen 200 ft. or 300 ft. from Woolwich Arsenal, and it traveled back
again to the arsenal half a mile against the wind uninjured.
The importance of such an apparatus might become manifest in any flight
of a balloon from a besieged place over the heads of an investing army.
The results of a rapid survey of the enemy's positions could be written
and dispatched from a height against the same current which wafted the
balloon, so as to fall within the lines of the besieged.
Given a light motive power, which it is hoped may soon be forthcoming,
Mr. Brearey anticipates the action of the machine as follows:
A surface will be provided according to the weight to be carried, the
supporting surface of a parachute being known. Upon being run down an
incline the envelope will be inflated by the pressure of the air, and
the wing arms raised to that point where their further elevation is
restrained by the pectoral cord. The machine will then naturally float
away from the incline, and the occupant must set his motor in action.
The downward blow of the wing-arms will cause the fabric immediately
attached thereto to imprison a mass of compressed air, and the
following wave will force it along the under side of the fabric. This
will cause propulsion.
The return or up stroke cuts off and diverts from the upper part that
air which, but for the rise of the wing-arms, would flow over the back,
and shunts it underneath, while that which is embraced in the concave
fabric following the up-stroke is thrown off in a wave to the rear
above the machine, and so on alternately.
During this energetic action the whole fabric is kept in a state
of corrugation, and to such extent is rigid. It possesses all the
properties of a plane, and superiority over a plane, inasmuch as it
propels itself, and upon cessation of action assumes the functions of a
parachute, the descent of which a man may regulate by a step backward
or forward.
The latest invention which has been completed upon a full scale is the
idea of Mr. H. C. Linfield, of Margate. It is really a plane-propelling
machine, but the planes are compressed, it may be said, into small
compass, being only two inches apart, and being of such number and
extent as to present 438 square feet of strained and varnished linen in
two frames, each five feet square. The dimensions of the machine are 20
ft. 9 in. in length, 15 ft. in width, and 8 ft. 3 ins. in height. It
runs upon four wheels; the two front wheels are 6 ft. in diameter, the
two hind wheels 3 ft. The frames before mentioned are fixed one on each
outer side of the front wheel at an upward angle. The wheels have been
tested to sustain a weight of 5 cwt.
The weight of the machine is 240 lb., and of its inventor 180 lb.
He sits between the wheels and works two treadles, which actuate a
nine-bladed screw 7 ft. in diameter, fixed in front of the machine, to
which he can impart 112 revolutions per minute. This suffices to enable
him to travel along a level road.