Improvements in the Art of Aerostation and Apparatus employed therefor.
Year: 1894

page_text: Date of Application, 20th June, 1894-Accepted, 21st July, 1894
COMPLETE SPECIFICATION.
Improvements in the Art of Aerostation and Apparatus employed
therefor.
I, JOSEPH HOFMANN of No. 1 Lichterfelderstrasse, in the City of Berlin,
Prussia, in the Empire of Germany, Counsellor of the Government, do hereby
declare the nature of this invention and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:-
My present invention relates to further Improvements in the Art of Aerostation
and Apparatus employed therefor for which I have applied for Letters Patent
No. 7919 of 21 April, 1894.
Experiments made with apparatus constructed according to my former invention
referred to have shown that it is not so essential to withdraw the atmosphere from
above the surface of resistance as to discharge the jet at a greater distance from
the surface of resistance, whereby the velocity of the said jet, exceeding by far the
amount necessary for the purpose to be obtained, will be able to moderate its said
velocity by carrying along with it the surrounding atmosphere and thereby supply
working power to the latter. Beside the mouth-piece proper, guiding surfaces for
the jet should be arranged only at such portions where the jet has already given
motion to larger volumes of the atmosphere.
I have further discovered that an air-ship constructed according to my former
invention referred to may very well serve to replace the captive balloon, but that a
flying machine destined to move independently still requires boilers of too large a
size to enable practical service for a sufficient length of time.
And I have further found by experience that the protecting surface employed in
combination with the surface of resistance should be constructed and arranged
according to certain modifications to answer various conditions.
The improvements in the art of acrostation and means for performing the same,
as hereinafter described, are destined to overcome the difficulties still connected
with the operation of my former invention.
In the accompanying drawings:
Figure I represents a flying-machine of great simplicity, destined to replace the
so called captive balloon. The steam, generated by a locomotive or stationary
boiler, is supplied by joint-pipes or hose-pipe to plane surfaces of resistance a, in
such a manner that the mixture of steam and atmosphere carried along by the
ejected steam bears against the said surfaces a. If we call the force acting upon
each of the said surfaces by the jet, then, not considering the small effect of
reaction, the power wasted will be 1, and the active power: 2. The said active
power, in its turn, is subdivided into a power: 3, which tends to force away the two
surfaces of resistance a (or to approach the said surfaces, if the arrangement be
reversed), and into a power: 4, which is the lifting power proper.
Figure 2 illustrates the upper portion of a captive flying-machine similar to that
of Figure 1, the surfaces of resistance, in this modification, are vaulted or curved,
instead of plane. The forces developed are indicated by the same numbers of
reference as in Figure 1. It will be readily understood that the power 1, in this
modification, is not wasted, as, in every portion of its way down to the lower edge
of the surface of resistance, it is forced to change its direction. Beside the primary
lifting power 4, there will, accordingly, be formed further lifting powers 4, in every
portion of the way of power 1. And further, in passing off the surface of resistance,
the counter-pressure of force K in the surface itself, being now free, will act in the
same way as the said forces 4.

page_text: Instead of discharging the jet radially, as shown, the same may be discharged
tangentially to the surface of resistance, as has been illustrated in my previous.
application referred to.
Figure 3 is a sectional elevation and Figure 3' a plan of a flying-machine destined
for free and independent aerial navigation.
Figures 30, 31, 32, 3 and 3' are vertical sections taken at the portions indicated
by 0, 1, 2, 6 and 7 of Figure 3.
In this construction, the wings of the machine form open channels, and the
protecting surface n, is arranged in front. In my previous construction the said
protecting surface was arranged below the surface of resistance a, and so it is in the
present modifications as illustrated by Figures 4 and 4", but, as shown in Figure 5,
the said protecting surface a may as well be placed in front of the surface a.
Accordingly, if it is desired to raise the machine represented by Figures 3 and 3
whilst moving forward, and if it is desired that the jet discharged for this purpose
from the nozzle C. Figure 44, and the atmosphere carried along by said jet, should
be kept free of the influence of the atmosphere over which the machine is moving.
then the protecting surface must either form a closed channel with the surface a,
as shown in Figure 4, or the said surface n must be arranged in advance of the
surface u, nt such inclination ns to exclude undue influence, that is, to force those
strata of the atmosphere, which could work such undue influence, to escape
downwards as indicated by the arrows in Figure 5. While, by the arrangement
illustrated by Figures 4 and 4, the said protecting surface n will simultaneously
act as an auxiliary supporting surface, the arrangement shown in Figure 5 will
serve to increase the surface of resistance a, thus being utilised for the purpose of
sailing.
As illustrated by Figure 6, the surface of resistance a may be double or hollow,
the upper surface being provided with suction uozzles, and the lower surface with
force or pressure nozzles. The atmosphere, being drawn in by the jet through the
suction nozzles, will be conducted off from the several surfaces a of the force
nozzles, as soon as the area of the channel is beginning to be filled.
The protecting surfaces n, as well as the surfaces of resistance a, may be
connected to each other and to the gondola by link connections instead of by rigid
connecting pieces, and by such flexible connections I obtain the desired facility to
meet all conditions of the variable force and direction of the wind, as also of the
desired variations of speed. Constructions of the kind, as an example, are
represented in Figures 7 and 7ª, the former being a sectional elevation and the
laiter a plan.
The central portion of the wings, as shown in Figures 3 and 34, is made rigid,
while the forward and rear portions are springy.
The main web of the wings is constructed to form a chimney for the furnace of
the boiler; the said web 1, at its upper surface, opens into the atmosphere, as at /',
while on its lower side, it is provided with suction nozzles, in such a manner that
the jet issuing from the mouth pièce d' carries the products of combustion along
with it and below the surface of resistance. The said mouth pieces care arranged
at a considerable distance from the funnels m, at the entrance of the hollow wings;
by this arrangement, I so arrange that a large volume of atmospheric air is carried
along by the jet, before its action on the machine itself.
Between the open channel of the surfaces of resistance of the wings and the said
funnels in, a tap d is arranged in such a manner that, as the machine is rising, the
said flap is lying down, while, as the machine descends, the flap is lifted to bear
against the web. thereby obtain this result, that the current of air rising
within the open channel cannot escape through the funnel, but is in some degree
guided down again by the said flap d.
The rudders o are so connected with the surface of resistance that, together with
the centre of gravity being arranged in advance of the axis of the wings, the
machine is enabled to be diverted, as desired, both in the horizontal and the vertical
plane.

page_text: For landing the machine without injuring the same by the shock, I have provided
a springy wheel p at the bow, and springy slide beams 7 at the stern of the gondola.
The boiler of the machine has not sufficient size to produce so much steam as
would be required to uniformly raise the machine; the size is calculated to be just
sufficient to raise the machine by single impacts, and to fly by the aid of gravity to
a certain extent in a horizontal plane, that is, in a flattened arc. Before the
working power obtained by the first impact has been spent, the second impact is
delivered, and so on, the impacts of the machine corresponding to the flapping of a
bird's wings on the surrounding atmosphere.
Between every two successive impacts, the nozzles are closed, and, accordingly,
the boiler has sufficient time to replace the steam that has been spent. If it should
happen that the boiler failed to supply steam, and if the atmosphere be calm, the
machine must be steered to ground, gradually and in flattened ares. But, if there
is some wind blowing, the operator will always, by cruising, be able to obtain,
partly from gravitation and partly from the pressure of the wind, sufficient power
for moving on. This will be much facilitated, if the surfaces of resistance and the
protecting surfaces are made adjustable, or if sails are provided, which, being set,
utilise the wind to furnish lifting power.
As has been mentioned before, the boiler is designed to deliver steam only at
intervals, and, in consequence, the water will be liable to spume. To counteract
all undue effects arising from this, I locate the steam pipes cinside the chimney,
thereby obtaining superheating of the steam. The same arrangement is provided
for any auxiliary blast pipes which may be provided to blow the fire of the
boiler.
In Figure 8, I have shown in dotted lines the path which will be described by
the flying machine in the atmosphere. It might be that, owing to this kind of
tossing motion, sea-sickness" will be caused to the navigators. In such case, the
line of motion should be changed as much as possible so as to approach the course
indicated by Figure 9, which will be performed by delivering the impacts of steam
in such quick succession as to make the deviations from the straight line so slight
as to be practically immaterial to the nagivators. An apparatus of great simplicity
for automatically producing such impacts of steam is illustrated by Figure 10.
The steam pipes c are shut by means of a slide valve S', under control of a piston
or diaphragm S, governed partly by a spring and partly by the pressure existing
in the boiler. An adjusting screw determines the degree of pressure at which the
slide valve opens. Now, as the slide valve S' and pipes c must be of a large area,
which is, as far as the pipes e are concerned, a consequence of their serving to
overheat the steam, each lift of the piston will be quickly followed by its descent,
and thereby impacts of steam will be produced.
In order to maintain a uniform inclination of the axis of the machine during its
ascents and descents within the short arc-shaped portions of its path, it will be
necessary to provide a deflecting surface to the rear, as has been described in my
previous application with reference to Figure 5. The same object will be obtained
by applying a motor to give continual impulsions in a horizontal direction, as
indicated in Figure 9. An air turbine constructed in the manner of the hurdy-
gurdy-wheels, receiving motion by a jet of steam and carrying a screw propellor,
will suit the purpose in question.
A still greater simplicity of construction may be obtained by providing the
apparatus for producing impacts of steam as shown in Figure 10, with suitable
means to act as a propellor. To avoid throttling the steam supplied by the boiler
on entering the pipes c, it is necessary to increase the momentuin of inertia of the
slide valve S. This may be done by oscillating bodies, which, at every stroke,
compress the spring t' in excess of its compression due to the pressure of the steam.
Now, if I construct the said oscillating bodies in the shape of a palmated foot, as
shown in Figure 10, the slide valve Si will open to such an extent and with such
rapidity as if a disc had been employed as the oscillating body of the section
indicated by Figure 11. But, during the return motion, the spring will act
r

page_text: against the surrounding atmosphere by the aid of the palmated feet, which assume
the shape indicated by Figure 11. If the apparatus illustrated by Figure 10 is
horizontally arranged, each impact of steam discharged from the nozzles c' against
the surfaces of resistance a, to lift the same, will be followed by an impact of the
rudder, on the surrounding atmosphere, said impact being worked by the
surfaces r, and tending to move the machine forward. If the said apparatus
illustrated by Figure 10 is arranged in a position inclined to the horizon the strokes
of the rudder r are immediately utilised for the lifting operation. But, if the said
apparatus is vertically arranged, the impacts of steam bearing against fixed surfaces
will alternate with the flapping of the wings upon the surrounding atmosphere,
both of which operations tend to lift the machine. Of course, the position of the
flaps (sides of the palmated feet) may be reversed in a manner to make the impacts
of steam coincide with the flapping of the wings, instead of alternating with the
same.
Referring to the working order of the apparatus as illustrated by Figures 9 and 10,
it should be observed that the working order of a nearly horizontally working
motor is out of comparison with that of a common aeroplane. In the said
aeroplane, the motor is destined to give the vessel a horizontal speed of such a kind
that the pressure of the calm atmosphere, acting in the direction of motion and from
below against the inclined surface, becomes equal to gravity.
But, according to my present invention, gravity is balanced without a motor, by
means of impacts on the atmosphere along fixed or adjustable wings nearly
vertically upon the direction of motion, and the horizontal motor is only employed
to prevent the axis of the machine from following the actual inclinations of the
small arcs of the path described by the machine, the rudder proper » being only
employed for steering the machine into another direction. The angle a, which the
axis of the machine is adjusted to take with reference to the horizon, may be equal
to nought.
If, in the present Specification, I have described the operation to be performed
by jets of steam, this lins been done for the reason that the greatest simplicity in
working the machine consists in making the steam of the boiler act immediately in
the manner of an ejector blast. But if it is desired or necessary to fly without
stopping to great distances, no possibility being given to take fresh water for the
boiler, the steam of the boiler must be employed to drive an auxiliary engine
which
compresses air to be fed to the nozzles. The waste steam, in this case, on
leaving the engine may be condensed and led back to the boiler. The condensation
of the steam may best be performed in the manner proposed by Maxim, that is, by
surface condensers, a system of pipes which may serve equally as a frame for the
supporting surfaces.
It will be also understood, that, in speaking of steam, this need not necessarily be
the steam of water.
In Figures 7 and 74 I have shown a machine for free aerial flight, in which
carbonic acid contained in a reservoir u enters into a heating coil pipe v, for the
purpose of forming, either by itself or in combination with a dripping or injecti g
apparatus to which supplies steam from water, the working steam for lifting the
machine as before described.
The said construction illustrated by Figures 7 and 74 contains another remarkable
modification, consisting in the surfaces of resistance being separate from the sailing
surfaces, and in a keel r being provided to prevent vacillations to either side; this
keel, together with the centre of gravity, being arranged in advance of the fulcrum
and together with the rudder arranged in the rear in a rising position, ensures the
desired stability of the new flying machine.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, 1 declare that what
I claim is :-
J
1. The method of flying or lifting loads into the air,, consisting in directing

page_text: currents of nir opposite to or diverging from each other against surfaces of
resistance inclined towards the said currents, whereby an upward component of
pressure is bestowed upon the said surfaces; and whereby, besides, the sail currents.
are made operative by reaction in passing off the said surfaces, substantially as and
for the purpose described.
2. The method of flying or lifting loads into the air, consisting in directing
currents of air mixed with the escaping products of combustion or with exhaust
steam or with both in an opposite direction to or diverging from one another
against surfaces of resistance inclined towards the said currents, whereby an upward
component of pressure is bestowed upon the said surfaces, and whereby besides the
said currents are made operative by reaction in passing off the said surfaces,.
substantially as and for the purpose set forth.
3. The method of flying or lifting loads into the air, consisting in intermittently
or by impacts directing currents of air or of air mixed with the products of
combustion, or with steam opposite to or diverging from each other against
surfaces of resistance inclined towards the said currents, whereby an upward
component of pressure is given to the said surfaces, substantially as and for the
purpose set forth.
4. A machine for aerostation or lifting loads into the air, having means (such as
an air-pump, ejector, blower, etcetera) to throw currents or impacts of air, or gases,.
or a mixture of air and gases or steam against surfaces of resistance, substantially
as and for the purpose set forth.
5. A machine for acrostation or lifting loads into the air, having means for
throwing currents or impacts of air, or gases, or a mixture of air with gases or steam
against surfaces of resistance, in combination with a surface of protection arranged
below or in advance of the said surfaces of resistance for the purpose of preventing
the said working currents or blasts from being unduly influenced by the sailing
motion of the machine substantially as set forth.
6. In a machine for aerostation or lifting loads into the air, the combination,
with means for throwing currents or blasts of air or of a mixture of air and products
of combustion or steam against surfaces of resistance, of an auxiliary propellor for
the purpose
of obtaining greater uniformity of forward motion, as also of assisting
the raising power substantially as set forth.
7. In a machine for aerostation, the combination, with means for throwing
impacts of air, or of a mixture of air with products of combustion or steam against
inclined surfaces of resistance, of an auxiliary propellor containing means for
opening and shutting the passages of steam combined with oscillating bodies of the
form of a palmated foot or folding oar, for the purpose of performing flapping
motions directed to the rear or downwards and coincident or alternating
with the impacts directed against the surfaces of resistance, substantially as
set forth.
8. In a machine for acrostation, the combination, with means for throwing
currents or impacts of air or a mixture of air and the products of combustion or
steam against inclined surfaces of resistance, of sailing surfaces separate from the
said surfaces of resistance and of a keel or keels arranged in a vertical or horizontal.
or inclined position, substantially as and for the purpose set forth.
9. In a machine for aerostation, the combination, with means for throwing
currents or impacts of air or of a mixture of air and products of combustion against
inclined surfaces of resistance, of means for condensing the exhaust steam and
returning the water into the boiler, substantially as and for the purpose set forth.
Dated this 19th day of June 1894.
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicant..