Note: Descriptions are shown in the official language in which they were submitted.
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This invention relates to apparatus for supporting
a human body in a floating condition, and in particular
to a skydiving simulator, that is to say an apparatus
for simulating the free fall conditions experienced by
a human body falling through the air at its terminal
velocity.
UDtil recently, it was possible for a person to
experience free fall conditions (that is to say to
practise skydiving) only during aparachute descent and
before the parachute had opened. Skydiving is a
stimulating and pleasurable activity, and requires the
development of special skills, particularly the
muscular control and co-ordination necessary to vary
the orientation of the body. Obviously, considerable
practice is necessary to acquire such skills.
Unfortunately, the cost of skydiving is considerable, -~
as each parachute jump is itself extremely expensive~
and results in only a few minutes in free fall
conditi.ons. As each parachute jump takes a consider-
able time (as it involves initial preparations, and
the landing and taking-off o~ the aircraft concerned),
it is not usually possible for a skydiver to make more
than three or four jumps a day. Consequently, it can
take a considerable time for a skydiver to learn the
necessary skills to produce a high quality of
performance. This problem is often exacerbated by
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bad weather, as, for safety reasons, skydivers only
operate when the weather is ~ood. Thus, although the
sport of skydiving is becoming increasingly popular,
its popularity is limited by the considerable expense
involved, and the time taken to learn the necessary
skills.
Another problem limiting the popularity of
skydiving is that it is a relative dangerous sport.
Moreover, many people are too timid to jump out of an
aircraft just for the sake of a few minutes pleasurable
experience.
In an attempt to reduce the costs and dangers
of skydiving, skydiving simulators have been built.
Such skydiving simulators are basically vertical wind
tunnels. Unfortunately, all the known simulators are
- extremely costly to build, being of a solid and
permanent construction. Consequently, although the
known simulators do reduce the cost and dangers of
skydiving, they are still relatively expensive, and
so-very few have been built.
The aim of the present invention is to provide
a skydiving simula$or which is simple and cheap to
manufacture, and which is easily transportable from
site to site.
The present invention provides a skydiving
simulator comprising a framework, a flying chamber
supported within the framework, the flying chamber
having an air inlet at the base thereof and an a~r
outl~t at the top thereof, and means for producing
an upward stream of air within the flying chamber,
wherein the flying chamber is made of tensioned sheet
material.
The flying chamber of this simulator is easily
removable from the framework, and the framework is
demountable, so that the entire simulator can be
taken down and transported to another site.
In a preferred embodiment, the flying chamber
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has a lower section whose side walls are substantially
vertical, and an upper section whose side walls are
inclined at a small angle to the vertical, the side walls
of the upper section being divergent with respect to the
central longitudinal axis of the flying chamber.
Advantageously, the side walls of the upper section make
an angle of between 10 and 15 with the side walls of
the lower section. Preferably, said angle is 12. The
lower section of the flying chamber constitutes a flying
section, and the upper section constitutes a diffuser
section for slowing down the velocity of the air, and
hence preventing a flyer rising too far up the flying
chamber.
Advantageously, the side walls of the lower section
of the flying chamber are made of transparent material.
- This permits the interior of the flying section to be
observed from outside.
In a preferred embodiment, the flyin~ chamber is
made of a plurality of identical strips of sheet material
which are joined together along their longitudinal edges.
Advantageously, the longitudinal edges of the strips are
zipped together. Prefera~ly, each of the strips has a
lower portion, an upper portion, and a flange extending
along the entire length of one longitudinal edge, the
lower strip portions defining the lower section of the
flying chamber, the upper strip portions defining the
upper section of the flying chamber, and the flanges
being connected to the framework to tension the flying
chamber. In this case, the l~wer portions of the strips
are made of transparent laminated polyvinylchloride
sheet material, and the upper portions and the flanges
of the strips are made of a fire-resistant
polyvinylchloride-coated woven polyester fabric, the
upper portion, the lower portion and the flange of each
strip being high frequency welded together.
In order to permit a flyer to enter the flying
chamber~ a removable access panel is conveniently
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provided in one of the lower strip portions. Prefer-
ably, the access panel is zipped into the associated
lower strip portion.
Advantageously, each of the flanges is fcrmed
with a looped end portion, and a respective tensioning
rod passes through each of said looped end portions,
the tensioning rods being adjustably attached to the
framework by means of screw threaded members at the
opposite ends thereof.
In a preferred ernbodiment, there are six strips
of sheet material, and the flying chamber has a generally
hexagonal configura-tion.
The upper section of the flying chamber may be
provided with venting slots and/or vortex generators.
These can be used to modify the velocity profile of
the air flowing upwards through the flying chamber.
The framework may be constituted by a plurality
of girders and a plurality of cross-pieces, the bases
of the girders being fixable to the ground, and the top
ends of the girders being interconnected by the cross-
pieces. Advantageously, the girders are symmetrically
disposed about the central longitudinal axis of the
flying chamber, and are inclined to said axis with the
bases of the girders further from said axis than the
top ends of the girders. The framework may further
comprise a plurality of vertical struts, there being
the same number of vertical struts as there are girders,
each vertical strut being positioned vertically below
the top end of a respective girder. Preferably, the
framework further comprises a platform positioned
around the base of the flying chamber, the platform
being supported on the vertical struts and by the
girders. This platform provides a convenient place
from which the interior of the flying chamber can be
viewed. Where the flying chamber is hexagonal and
constituted by six strips of material, the~re may be
six girders and si~ cross-pieces.
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In a preferred embodiment, the means for producing
the air stream is constituted by a plurality of motor/
fan units. Advantageously, each of the motor/fan units
is provided with a curved duct, the curved duct having
an inlet end surrounding the fan and an outlet end
positioned at the base of the flying chamber. In order
to facilitate with the efficient flow of air along the
ducts, each of the ducts may be provided with internal
baffles ~or directing the air stream from the inlet end
to the outlet end thereof. Preferably, there are three
motor/fan units, each of which is mounted on a variable-
angle stand.
Advantageously, a mesh grid is provided at the
base of the flying chamber.
The invention also provides apparatus for support-
- ing a hu~an body in a floating condition, the apparatus
comprising a framework, a flying chamber supported
within the framework, the flying chamber having an air
inlet at the base thereof and an air outlet at the top
thereof, and means for producing an upward stream of
- air within the flying chamber, wherein the flying
chamber is made of tensioned sheet material.
A skydiving simulator constructed in accordance
with the invention will now be described, by way of
example, with reference to the accompanying drawings,
in which:-
Fig. 1 is a plan view, partially broken away,
of the simulator;
Fig. 2 is an end elevation of the simulator;
Fig. 3 is a perspective view of part of the
simulator; and
Fig. 4 is a perspective view of a motor/fan
unit forming part of the simulator.
Referring to the drawings, the skydiving simulator
comprises a flying chamber A which is supported by an
outer framework B. The framework B includes six
Warren girders 1, six cross-pieces 2, and six vertical
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struts 3. The girders 1, the cross-pieces 2 and the
struts 3 are made of lightwelght aluminium. The girders
1 are provided with base plates la which are bolted to
a concrete base 4. The base plates la are positioned at
the corners of a regular hexagon, and the girders 1 are
inclined at a small angle to the vertical so that their
top ends lb also lie at ~he corners of a regular hexagon.
The top ends lb of the girders 1 are interconnected by
the cross-pieces 2. The struts 3 are positioned
vertically below the top ends lb of the girders 1, and
so lie at the corners of a regular hexagon that is the
same size as that formed by the top ends lb. The struts
3 are provided with base plates 3a which are bolted to
the base 4. A platform 5 is supported on the tops of
the struts 3 and by the girders 1. The platform 5
surrounds the flying chamber A, and so constitutes a
viewing platform (as is described below).
The flying chamber A is made from six identical
strips 6 of sheet material. Each strip has three
portions, namely a lower portion 6a, an upper portion
6b and a flange 6c. The longitudinal edges of the
upper and lower portions 6a and 6b of each pair of
adjacent strips 6 are detachably connected together
by zips 7 to form a generally hexagonal structure.
The flanges 6c extend radially outwards from the
corners of this hexagonal structure, the flanges being
used to fasten the flying chamber A to the outer
framework B in a manner to be described below. As
shown best in Figs. 2 and 3, each of the strips 6 is
such that its portion 6b will naturally lie at an
angle of about 12 to its strip 6a. Thus, the flying
chamber A has two sections, namely a lower (flying)
section A', and an upper (diffuser) section A". As
is described below, a person can enter the flying
section A' to practise skydiving, and the diffuser
section A" is provided to prevent a flyer rising too
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g
high in the flying chamber A. The strip portions 6a
are made of transparent laminated polyvinlychloride
sheet material,whereas the strips ~b and the flanges
6c are made of a fire-resistant polyvinylchloride-
coated woven polyester fabric such as Trevira
(Registered Trade Mark). The strips 6a are either
sewn or high frequency welded to their strips 6b and
flanges 6c. Thus, the strips 6a permit the interior
of the flying section A' to be observed from outside,
and in particu]ar from the viewing platform 5. One
of the strips 6a is provided with a panel 6d (shown
in dashed lines in Fig. 2) which can be removed to
enable a person to enter the flying section At.
Conveniently, this access panel 6d is zipped to the
associated strip 6a.
As shown in the inset portions (in~icated by the
arrows C) of Fig. 3, the end portion o~ each flange
6c is folded back on itself to form a closed loop
6e. 4 respective tensioning rod 8 passes through
each of the loops 6_. Each tensioning rod 8 is
provided with tensioning bolts 9 at the top and
bottom ends thereof. These bolts 9 are adjustably
connectible to brackets ~0 provided at the top ends
1_ of the girders 1 and on the platPorm 5 respectively.
Hence, by suitably tightening the bolts 9, the flying
chamber A can be supported within the outer framework
B under tension.
The flying chamber A is supplied with an
upwardly-directed stream of air by three motor/fan
units 11. As shown in Fig. 1, the motorlfan units 11
are equispaced with respect to the vertical longitud-
inal axis of the flying chamber A. Each of the units
has a motor 12, a ~an 13 and a curved duct 14 for
directing the air output of the fan vertically
upwards into the flying chamber A. Moreover, as
shown in Fig. ~, the upp~r outlet end 1~a o~ each
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duct 14 is of smaller cross-sectional area than its
lower inlet end 14b. Consequent:Ly, as air enters the
flying chamber A, it is accelerated owing to the venturi
effect. Each duct 14 is provided with internal baffles
15 for deflecting the air efficiently through the
required angle. Each of the motors 12 is mounted on a
variable-angle stand 16, so that each of the motors can
be bolted to the base 4 in such a manner that the
direction of the air stream pushed out by its fan 13
can be varied. As shown in Fig. 2, the motors 12 are
angled so that their output air streams are directed at
angles of about 60 to the horizontal.
A mesh grid 17 is provided at the base of the
flying chamber A ~just above the outlet ends l~a of
the ducts 14. The grid 17 is provided to prevent
- persons in the flying section A' from seeing the fans
13. The grid 17 would also prevent persons falling
into the ducts 14 in the event of failure of the
motors or a substantial reduction in their output.
Tn use, a user enters the flying section A' via
the access panel 6d. The motors 12 are rated so as
to provide an upward stream of air of sufficient
velocity to support a flyer floating in the flying
section A'. As mentioned above, the upper divergent
section A" of the flying chamber A defined by the
strip portions ~_ constitutes a diffuser, and so
prevents a flyer from being lifted by the air stream
out of the top of the flying chamber. In other words,
the flying section A' of the flying chamber A acts as
a venturi tube, while in the section A" the air is
slowed down cefore it is discharged into the atmosphere,
thereby preventing a flyer from rising too high in
the flying chamber. It has been found, in practice,
that the angle of divergence of the upper section
of the flying chamber A should be between about 10
and about 15. In the embodiment shown, this angle
is 12.
.. . . . ~
` ~Zl(~959
' 11-
It will be apparent that the simulator described
above could be modified in a number of ways. ~or
example, the height of the structure and the lengths of
the air ducts 14 could be altered to provide different
velocity profiles within the flying section A' of the
flying chamber A. In particular, the motors 12 could
be positioned so that the fans 13 emit air horizontally.
This has the advantage of increasing safety as the fans
are further away from the flying chamber A. Unfortunately,
it means that the ducts 14 must be considerably longer
than those shown, so that the overall size of the
structure is increased and some efficiency is lost.
It is also possible to reduce energy losses by varying
the dif~user angle (that is to say the angle o~ divergence
of the diffuser section A" of the flying chamber A),
or by providing re-energising air slots, vortex
generators screens and turning vanes in the upper
section. Swirl may be reduced by pre-rotational vanes
and nacelles, along with symmetrical straightener
vanes. Airflow control can be achieved by providing
venting slots in the diffuser section A" of the flying
chamber A, or by an ~.C./D.C. electric or internal
combustion motor speed controller fed by pressure/
flowmeter transducers in the flying section A'.
It would also be possible to house the simulator
within a permanent or temporary building structure.
Particularly where transportability is desirable, it
is preferable to provide the simulator with a
temporary, easily-transportable building structure.
For example, a building structure having a framework
made of Warren girders and a covering made of
tensioned sheet material is particularly suitable.
Such a structure is manufactuered by Spandrel Orbits
Structures Ltd.
~
It will be apparent that the skydiving
.
lZl(~959
simulator described above has a number of advantages
compared with known arrangements. In particular, it
is of modular construction and can be manufactured
at a relatively low cost from a small number of
standard parts. Moreover, it can be supplied in kit
form and is easy to transport and erect, so that the
sin;ulator can be sited practically anywhere (the only
site requirement being a solid base on which to bolt
the structure). The girders 1 and cross-pieces 2
being made of lightweight aluminium facilitate the
transportability of the structure.
Another advantage of this simulator is that the
flying chamber A is made of sheet material. This
provides a cushioning effect if impacted by a flyer.
Moreover, constructing the flying chamber A from
tensioned sheet material is cheaper than covering a
solid-walled flying chamber with foam cushioning.
The use of transparent sheet material for the flying
section A' has obvious advantages (not present in
solid prior art simulators) of allowing spectators
and instructors to observe flyers, as well as
facilitating filming and photography.
As described above, the use of sheet material
also facilitates the formation of the diffuser
section A" which is an important safety feature
preventing a flyer from rising too high. Without
this diffuser section A" there would be a risk of
a child (or a slightly-built adult) being lifted
right out of the top of the flying chamber A if the
velocity of the upward air stream in the flying
chamber was too high. Obviously, flyers of different
weights will tend to fly at different heights within
the flying section A' of the flying chamber A (with
heavier flyers nearer the base of the flying section),
and so, without the provision of the diffuser section
A", there would be a danger of a lightweight flyer
rising out of the top of the flying chamber A, even
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- 13
if the outputs of the motors 12 were varied to try and
prevent this happening.
Another important advantage of this simulator is
its versatility. Thus, because of its modular
construction, it is a relatively simple task to increase
its size. The embodiment described is intended for a
single flyer. However, if alarger simulator is
re~uired (say for two or four flyers), the entire
structure can be increased in size by adding further
~irders 1 and cross-pieces 2, and by zipping in further
strips 6 of sheet material. For example, by using
twelve girders 1, twelve cross-pieces 2, twelve struts
3, and twelve strips 6,a four-man simulator could be
made. In this case,twelve motor/fan units 11 would be
required, and the flying chamber A would have the
shape of a regular dodecagon.
Yet another advantage of the simulator described
above is that the motor/fan units 1~ are not positioned
below the flyer, so there is no chance of the flyer
falling into rotating parts in the event of a reduction
in power. Moreover, by using a plurality of motor/fan
units 11, the arrangement avoids the safety and
balancing problems of one large rotating mass.
Furthermore, in the event of one motor/fan unit 11
failing, a flyer would not fall heavily to the base
of the flying chamber A, but would gradually descend
owing to the upstream of air from the remaining units.
As mentioned above, the use of a plurality of motor/
fan units 11 facilitates the enlargement o the
simulator, as it is relatively easy to add further
standard units as the size of the flying chamber A
is increased.
The provision of the mesh grid 17 has a
psychological advantage in that it prevents a flyer
looking down the ducts 14 and seeing the fans. Thus,
a flyer is not disturbed by seeing moving.parts even
though the simulator is designed to prevent anyone
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falling into such moving parts.
The simulator described above can be used not
only for training skydivers, but also for military
training of parachutists, as a recreational attraction
in fun ~airs and amusement parks, or even for medical
and therapuetic purposes.
