Improvements in Aerial machines.
Year: 1893

page_text: Date of Application, 2nd June, 1893
Complete Specification Left, 31st Mar., 1894-Accepted, 5th May, 1894
Improvements in Aerial machines.
I, HIRAM STEVENS MAXIM, of Baldwyn's Park, Bexley, in the County of
Kent, Mechanical Engineer, do hereby declare the nature of this invention to be
as follows: -
My invention relates to aerial machines and comprises the improvements
hereinafter set forth.
I am well aware that narrow superposed planes have been proposed heretofore
for aerial machines but such planes have not hitherto been combined with the
machine in the most advantageous manner so as to yield the best results. One
feature of my present invention relates to the provision in an aerial machine of
small lifting planes arranged not directly over each other as has heretofore been
proposed but in an inclined position, that is to say, the upper planes being in rear
or in front of the lower ones. I prefer that each plane of said series of superposed
planes shall have its forward edge just in rear of the stern of the plane immediately
under it. This construction or arrangement of planes secures all the advantages of
vertically superposed planes without the disadvantage of offering increased
resistance to the flight of the machine as is the case in the previous arrangements
owing to the contracted spaces between the planes through which spaces the air
must pass.
In my improved construction the air is well clear of one plane of the
series before it strikes the next and consequently its passage through the machine
is not impeded. In such an arrangement of planes the centre of lifting effort is
independent of the speed, that is to say, does not change with the speed, and hence
it is feasible to arrange that the centre of gravity of the machine shall always be
under the centre of lifting effort which is a great advantage. Moreover such a
series of planes are but little affected by a side wind when the machine is starting ;
the only resistance they offer is that due to their inclination, and the cutting of the
air by their flight; and when rapidly descending they have a tendency to move in
a forward or backward direction which has the effect of greatly diminishing the
velocity of the fall.
Another feature of my present invention relates to the surface condensing tubes
for condensing the exhaust steam or vapour discharged from the engine. In the
Specification of a previous Patent granted to me No. 19228 A.D. 1891 I have shown
condensing tubes placed approximately lengthwise of the machine which I now
find is not the most advantageous arrangement. I therefore now propose to make
my condenser in such manner that the tubes shall move sidewise through the air
and at the same time be made of such shape as to be suitable for forming very
efficient lifting planes. In order that water may not accumulate in said tubes I
incline them preferably from the outer ends thereof that is from the sides of the
machine downwards towards the centre of the machine. The exhaust steam or other
vapour will enter said condensing tubes at the higher ends thereof and will flow
downwards to a central down take pipe and thence to the reservoir or pump.
arrangement of the condensing tubes has the further advantage of assisting to right
the machine in case it heels over, as whichever way the machine tilts the lower side
of the condenser for the time being will have the greatest lifting power and thus
will tend to restore the balance, and to keep the machine upright. The condensing
tubes are preferably made wide and thin, and may have a symmetrical crescent
section or be deeper at the forward than at the rear edge.
This
The tubes may be made of aluminium preferably hardened by the addition of a
little titanium or copper. They are of very thin section and therefore very light.

page_text: It is not necessary to make a condenser of all the superposed lifting planes, and
consequently I sometimes combine with a condenser such as described a number of
plain superposed lifting planes made of wood, cloth, thin metal or other light
substance.
The framework of the machine is suitably designed to support the condenser
tubes and lifting planes at the proper angle. The supports or stays of the frame-
work may be hollow and very thin and of oval or elliptical section so as to cut the
air with great facility and at the same time furnish a passage way for the exhaust
steam and condensed water passing to and from the condenser.
An important feature of my invention is the combination in a steam or vapour-
driven aerial machine of a large number of superposed lifting planes placed either
vertically or inclined as above described with one or more large aeroplanes such as
described in the Specification of my prior Patent above referred to, and either with
or without rudders as described in said Patent. Said superposed lifting planes may
or may not be constructed to form condensers.
A further important feature of my invention relates to a peculiar construction of
the large aeroplane for the purpose of overcoming a great difficulty hitherto
experienced in obtaining an aeroplane which should not be detrimentally distorted
by the pressure of the air. I have found by experiment that if the plane be made
of two separate sheets or thicknesses, the lower being drawn tight and straight
across the framework of the machine and preferably perforated, and the upper one
being allowed to bag, the air will pass through the lower fabric and all or nearly
all the lifting will be effected by the upper fabric while the lower fabric will
remain straight. The lower fabric has about the same pressure on both sides
thereof and therefore offers a plain or regular curved surface to the air. The dis-
tortion of the upper fabric does not hinder the free flight of the machine.
The grooves formed by the bagging of the upper sheet of the plane are
longitudinal, their shape being determined by the longitudinal members of the
framework.
I propose in this machine to use naphtha as the fuel. The naphtha is first pumped
from the reservoir into a vapour generator, which is heated by burning a portion
of its contents thereunder, the supply for such purpose being automatically regulated
by suitable devices. The said generator or vapourizer is suspended in such a
manner that when it is filled to the proper level with oil its weight operates to
diminish the rate of influx of oil, while on the other hand if it becomes too light it
rises and increases the rate of influx of oil. The vapour from the oil is conducted
to the boiler fire where it is made, by an injector arrangement, to induce and mix
with a large current of air and is then distributed through a burner formed by a
number of perforated pipes. The main pipe, which constitutes the distributor of
the mixed air and oil vapour, provided with an inner tube having a large number
of openings in the side thereof each fitted with a short radial pipe one calibre or
more in length so that the mixed vapour and air which issues from the inner tube
and enters the outer tube does so without setting up any longitudinal currents in
the external tube. The inside ends of said short radial tubes are cut off at an angle
to catch the gas more readily and deliver same into the outer tube. The steam
pressure in the boiler operates directly upon an equilibrium valve, in such a manner
that when the pressure rises above a predetermined limit it immediately checks the
flow of the oil vapour and thus reduces the fire. In this manner the steam pressure
is maintained constant. The feed water entering the boiler induces a forced circula-
tion, and the steam after leaving the boiler is arranged to pass over the top of the
system of tubes forming the boiler whereupon its moisture is evaporated and it is
slightly superheated.
The engine may be simple or compound

page_text: 111
I, HIRAM STEVENS MAXIM, of Baldwyn's Park, Bexley, in the County of
Kent, Mechanical Engineer, 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 invention relates to aërial machines or vessels and comprises the improve-
ments hereinafter set forth.
An important feature of my present invention is the provision of small or narrow
lifting planes arranged not directly over each as has heretofore been proposed but
in an inclined series, that is to say, the upper planes being in rear or in front of the
lower ones. I prefer that each plane of said series of superposed planes shall have
its forward edge just in rear of the stern of the plane immediately under it.
Another feature of my present invention is the apparatus for condensing the
exhaust steam or vapour discharged from the engine. In the Specification of a
prior Patent granted to me No. 19,228 A.D. 1891 I have described and shown
condensing tubes placed approximately lengthwise of the machine; I now find that
this is not the most advantageous arrangement. I therefore now propose to so
construct and arrange my condenser that the tubes shall move sidewise through
the air, thereby improving their condensing effect. I, in fact, utilize the lifting
planes above referred to or a portion of them for the purposes of a surface con-
denser. The series of planes may be placed in front of or behind the screw
propeller, or it may be divided, one part being placed in front of the propeller and
another part behind the same, or other suitable disposition of the planes may be
adopted. The framework of the machine is suitably designed to support the
condenser tubes and lifting planes at the proper inclination. Portions of the
framework are made hollow and very thin and of oval or elliptical section so as to
cut the air with great facility and at the same time furnish a passage way for the
exhaust steam and water passing to and from the condenser.
A further important feature of my invention is the combination with a vertical
or inclined series of superposed lifting planes of one or more large aeroplanes such
as those described in the Specification of my prior Patent above referred to, and
either with or without rudders as described in the said Specification.
My invention also comprises an improved construction of the large aeroplane for
the purpose of overcoming a great difficulty hitherto experienced in obtaining an
aeroplane which should not be detrimentally distorted by the pressure of the air.
I have found by experiment that if the plane be made of two separate sheets or
thicknesses, the lower sheet being drawn tight across the framework and preferably
perforated, and the upper one being allowed to bag, all or nearly all of the lifting
will be effected by the upper fabric, while the lower fabric having about the same
pressure on both sides thereof will offer a flat or a regular curved surface to the
air and will not impede the flight of the machine. The distortion of the upper
fabric does not hinder the free flight of the machine. I therefore now propose to
construct my aëroplane on this principle.
My said invention also provides an important improvement in the apparatus for
distributing the mixture of air and oil vapour underneath the steam generator,
and comprises various other improvements hereinafter fully described.
Referring to the accompanying drawings,
Figure 1 is a longitudinal section of an aërial machine or vessel constructed in
accordance with my invention.
Figure 2 is a rear elevation of the machine, the large aeroplane being shown in
section.

page_text: Figure 3 is a longitudinal section of the aeroplane showing the shape assumed
during flight.
Figure 4 is a similar section showing its shape when at rest.
Figure 5 is a view on a greatly enlarged scale of a portion of one of the inclined
condenser tubes, showing in section the thin hollow vanes constituting parts of the
condenser and the superposed lifting planes.
Figure 6 is a view on an enlarged scale of a portion of the steam of vapour
generator, showing in section the device for distributing the mixture of gas or oil
vapour and air, the automatic regulating or controlling valve for the gas, and the
stop valve for the gas, hereinafter described.
Figure 7 illustrates a modified construction of the machine wherein a portion of
the inclined series of lifting vanes is forward of the propeller, and another portion
is aft of the propeller.
Figure 8 shows another modification where the whole of the inclined series of
lifting planes is aft of the propeller.
Like letters of reference denote corresponding parts throughout the drawings.
A is the boly or car of the machine; B is the large aeroplane; in some instances
I provide two or more such planes; C, C¹ are the fore and aft rudders carried by
struts or spars c, c' which are secured to the fore and aft edges of the aéroplane,
and further supported by stays d, d from the top of the masts D, D. The rudders
swing upon bearings e, c³ and are controlled by a windlass F through steering
ropes f, f. The ropes for the forward rudder pass inside the frame to the
windlass. E, E are hollow struts connecting the aeroplane to the body or car A.
The car A is constructed of thin steel tubes securely fastened together to form a
strong stiff frame upon or in which the various working parts of the machine with
the exception of the engines are placed. The said frame is covered with cloth or
other fabric to form a smooth exterior surface. The shape or configuration of the
car is such as will pass through the air without offering undue resistance.
G is the steam generator; H is the gas or oil vapour generator; J is the water
tank into which the condensed steam from the condenser drains; and K is the
naphtha tank. L, L are the motor engines placed above the car and beneath the
aeroplane. M, M are the screw propellers.
N, N are the small superposed lifting planes which as hereinbefore described are
arranged to form an inclined series somewhat resembling the steps of a wide staircase.
The face of each plane is slightly inclined upward and forward to ensure the necessary
lifting effect. Each of the planes measured from front to back is narrow, but
they extend laterally entirely across the vessel and project beyond the sides
thereof, and measured in that direction are very long as clearly indicated in the
drawings.
I am well aware that such planes have been proposed heretofore for aërial
machines but they have not hitherto been combined with the machine in the most
advantageous manner. That is to say, they have been arranged to form a vertical
series, and not an inclined series. My improved construction or arrangement of
planes secures all the advantages of vertically superposed planes without the dis-
advantage of offering increased resistance to the flight of the machine as is the
case with a vertical series of planes owing to the contracted spaces between the
planes through which spaces the air must pass. In my improved construction each
plane is set so far to the rear of the one below it that the air is not compressed
when passing between them, but is clear of one plane of the series before it strikes
the next and consequently it is merely deflected very slightly from its course by
each plane, its passage through the machine being unimpeded. With such super-
posed planes the centre of lifting effort is independent of the speed, that is to say,
does not change with the speed, and hence the centre of gravity of the machine
always remains under the centre of lifting effort which is a great advantage.
Morcover such a series of planes is but little affected by a side wind when the
machine is starting; and when rapidly descending they have the effect of greatly
diminishing the velocity of the fall.

page_text: The planes N are shown connected at their outer ends to a pair of outer inclined
tubes O, O', and at their inner ends to a pair of inner tubes O, O. The outer
ends of the planes are slightly higher than the inner ends thereof as clearly shown
in Figure 2. This construction has the effect of diminishing rolling and of
assisting to right the machine in case it heels over. For when the machine rolls,
the vanes on the side which is depressed are brought nearer to a horizontal position,
in which position they have greater lifting effect than when inclined, while those
on the other side of the machine being still more inclined to the horizontal have
less lifting effect, consequently the machine tends to right itself immediately. The
centre area between the inner inclined tubes O, O is occupied by a series of hori-
zontal vanes Nº. In some cases I dispense with these central vanes, and provide a
single ceutral inclined tube O to carry the inner ends of both series of vanes N.
The tubes O act as struts to support the aeroplane.
I utilize some or all of said lifting planes N as surface condensers for condensing
the exhaust steam or vapour coming from the engines. For this purpose I make
said lifting planes hollow, and preferably in transverse section as indicated in
Figure 5, that is to say, but very slightly convex. They communicate with the
interiors of the tubes O, O' and form channels for the passage of the exhaust
steam or vapour. Said tubes may have a symmetrical crescent section or be deeper
at the forward than at the rear edge. They may be made of aluminium preferably
hardened by the addition of a little titanium or copper; and being very narrow in
transverse section they are very light. The exhaust steam or other vapour from
the engines travels along the exhaust pipes P to a transverse pipe P₁ (which com-
municates with the outer inclined pipes O') and then enters the condensing tubes N
at the higher ends thereof and flows downward to the central downtake pipes O
and thence drains into the tank J. The inclined arrangement of condenser tubes N
prevents any lodgment of water therein.
It is not necessary to utilize as a condenser all the lifting planes N, and
consequently I sometimes combine with a condenser such as described a number
of plain superposed lifting planes made of wood, cloth, thin metal or other light
substance.
The aeroplane B consists of a suitable frame trussed and stayed with wires, and
covered on both sides with cloth or other fabric b, b. Said fabric completely
envelops the framework and is securely joined at its edges so as to form a bag.
6, indicate short struts which are secured at intervals to the frame and suitably
stayed by wires to keep them upright. Said struts form supports for the upper
fabric b. The proper or desired curvature of the said fabric b is maintained by
the system of wire trusses which supports the struts 62, 6². I form a hole b³ or two
or more holes in the lower fabric & to allow the air to pass freely into the interior
of the bag. The pressure of the air in the bag sustains the upper cloth and
produces a uniform figure, any grooves therein determined by the system of
trussing being longitudinal and therefore not such as will interfere with the flight
of the vessel.
I propose in this vessel or machine to use naphtha as the fuel. The naphtha is
first pumped from the reservoir K into the vapour generator H, which is heated
by burning a portion of its contents thereunder, the supply for such purpose being
automatically regulated by suitable devices such as those described in the
Specification of Letters Patent No. 19,254 A.D. 1892. The said generator or
vapourizer is suspended from a lever / which is pivoted at and connected by a
spring-controlled cord 2 to the delivery valve of the feed pump Q in such a manner
that when the vapourizer is filled to the proper level with oil its weight operates
to diminish the rate of influx of oil, while on the other hand if it becomes too light
it rises and increases the rate of influx of oil. The vapour from the oil is
conducted to the boiler fire where it is made, by an injector arrangement R,
Figure 6, to induce, and mix with, a large current of air, and the mixed vapour
and air is then distributed through a burner formed by a number of perforated
pipes. The main pipe S, which constitutes the distributor of the mixed air and

page_text: oil-vapour, is provided with an inner tube S¹ having a large number of openings in
the sides thereof each of which openings is fitted with a short radial pipe S2 one
calibre or more in length, so that the mixed vapour and air which issues from the
inner tube and enters the outer tube does so without setting up any longitudinal
current in the external tube. The inside ends of said short radial pipes S are cut
off at an angle as clearly shown in Figure 6 to catch the gas more readily and
deliver the same into the outer tube. The steam pressure in the boiler operates to
control the flow of gas or oil vapour in accordance with its pressure, checking the
flow when the steam pressure is high, and increasing the flow when the steam
pressure is low. Such a device is described in the prior Specification above
mentioned No. 19254. In the present instance V is an equilibrium valve for
controlling the supply of gas. VI, VI are springs which tend to keep the valve
open, and act against the pressure of the steam coming through the pipe v which
pressure tends to shut the equilibrium valve. The valve will remain open until
the steam pressure overcomes the strength of the springs and will then close. In
this manner the steam pressure is maintained approximately constant.
To allow of shutting off the supply of gas instantaneously if necessary I construct
the distributing apparatus with a tripping device as follows, that is to say, the
stop-valve W is furnished with a strong spring W' which tends to keep the valve
closed. To open the valve I provide a screw handle W2 for controlling a lever W
which is connected to the valve spindle, and is pivoted to a link W which
constitutes the fulcrum for the lever. It is obvious that by screwing the handle W2
in and out, the valve can be opened and closed. The handle W' is screwed
through a bridge-piece W which is pivoted at W to the gas-inlet pipe. In case
it is desired to shut off the gas instantly, all that need be done is to throw back
the bridge piece W' thus sliding the screw handle over the end of the lever W
and liberating the latter at once, whereupon the spring W' will instantly close
the valve. The feed water is fed to the boiler by the same pump Q that feeds
the naphtha to the vapourizer. On entering the boiler the water induces a forced
circulation as described in the before mentioned Specification No. 19254". I
dispense with the side steam and water tubes of the boiler illustrated in the said
Specification and I convey the steam direct to the central drum, whence it is
led to a system of tubes in the upper part of the boiler, wherein its moisture
is evaporated and it is slightly superheated. The motor engine may be simple or
compound.
The machine when on the ground rests on four wheels T which are mounted
in bearings at the ends of arms T¹. These arms are secured upon rock shafts T'
to which are attached levers T³. The ends of said levers are secured to
compressible or collapsable cylinders T which are carried by the body of the car
and which are filled with air at a sufficient pressure to sustain the weight of the
machine. A small pipe t connects each cylinder 14 with a gauge t' which shows
the pressure of air in the collapsable cylinders and therefore serves to indicate
the weight of the machine. For steering the machine when on the ground I
provide for turning the rear wheels T in their bearings by suitable gear controlled
by a band-wheel T
In the modification of my invention illustrated in Figure 7 I divide the combined
superposed lifting planes and condenser into two parts, one part being placed
forward of the propellers, and the other part aft of the propellers. I prefer that
the condenser in front of the propellers shall be made up of two wing portions,
and the part in rear of the propellers of one central portion. This construction
is such as would result from transferring the central portion of the single
condenser to a position behind the propellers.
In Figure 81 have illustrated another modification wherein the whole of the
condenser is in rear of the propellers.
In both of these modifications the centre of lifting effort of the superposed
planes and large aëroplane is so adjusted as to be above the centre of gravity of
the machine.

page_text: The hollow superposed lifting planes arranged in respect to the screw propellers
as described and shown in Figure 1 or in Figures 7 and 8 form a very
advantageous condenser for the exhaust vapour from the motor, inasmuch as the
air being forcibly drawn or pushed therethrough by the screw propellers very
rapidly cools the hollow planes.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. In an aërial machine or vessel, a series of superposed lifting planes inclined
or arranged step-wise, for the purposes specified.
2. In an aërial machine or vessel, an inclined or step-wise series of superposed
lifting planes arranged with their outer ends higher than their inner ends, for the
purpose specified.
3. In an aerial machine or vessel, an inclined or vertical series of superposed
lifting planes, all or some of which are made hollow and serve the purpose of
a surface condenser, and which series of planes is constructed substantially as
described with reference to the drawings, or otherwise suitably constructed to
operate as specified.
4. In an aërial machine or vessel, an inclined series of narrow superposed lifting
planes which may or may not be constructed to form also a surface condenser,
arranged in combination with one or more large aeroplanes placed above said
superposed planes, substantially as described, for the purpose specified.
5. In an aerial machine or vessel, a series of narrow superposed lifting planes
constructed to form a surface condenser for the exhaust vapour from the motor,
and arranged partly in front and partly behind the screw propellers, substantially
as specified.
6. In an aërial machine or vessel, an aeroplane formed of a suitable rigid frame
approximating in shape to the desired finished contour, and covered both at the
top and bottom with thin fabric, the bottom covering having one or more perforations
therein, or other means for maintaining air pressure between the coverings during
the flight of the vessel, substantially as described.
7. The injecting and distributing apparatus as described with reference to
Figure 6 operating as and for the purposes specified.
8. The inner tube fitted with short radial pipes for delivering the mixture of air
and gas or oil vapour into the main distributing tube of the burner, substantially
as described.
9. An aerial machine or vessel, constructed substantially as described with
reference to the accompanying drawings.
Dated this 31st day of March 1894.
Dated this 31st day of March 1894.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.