AIR.5IIIP

The present invention relates to a balloon/airship.

There are in the main tvro tjφes of balloons/airships in use at present, which differ in the method of providing the necessary lift for a given balloon/airship.

The balloon/airship belonging to the first type employ hot gases with which a balloon/airship is filled and thus, owing to the lighter density of these hot gases than the relatively cool surrounding air, the necessary lift is provided for the weight of the balloon/airship itself and for the ballast. These hot gases are obtained as products of combustion of air and fuel. As the hot gases continuouslylose their heat to the surrounding atmosphere and cool down so should the firing be either continuous or intermittent in ordyr to maintain the lift.

The balloon/airship belonging to the second type employ gases lighter than air such as hydrogen or helium. These gases are enclosed in a gas- tight balloon envelope. They do not require any heating and they assume the temperature of the surrounding air.

There are obvious disadvantages associated with these two types. The first type has at least four disadvantages:

1) Fuel has to be provided for firing and its weight will have to be added to the total weight of the balloon/airship.

2) The stored fuel and the burners occupy valueable space in the busket.

3) The fact that fuel is required for firing imposes a constraint on the distance a balloon/airship-,can fly before it has to land.

4) Frequent attention has to be paid to the firing and the maintenance of the lift.

The second type has at least two disadvantages:

1) The low density gases which are employed are expensive.

2) Hydrogen and some other low density gases present explosion hagards.

According to the present invention there is provided a balloon/airship embodying two envelopes which are so constructed that one envelope, the inner one, is enclosed by another envelope, the outer one, both the envelopes forming an integrally functioning double envelope of the balloon/airship and having an enclosed gas/air space within it into which gas/air is admitted in order to inflate the balloon/airship.

A specific embodiment of the present invention will now be described by way of example and with reference to the accompanying drawing in which:

Figure 1 depicts the outside view of the balloon/airship.

Figure 2 depicts the cross-section of the balloon/airship along the plane including its axis. Figures 3 and 4 depict the cross-sections of the two envelopes at right angle to their surfaces. Figure 5 depicts a different construction of the inner envelope. Figure 6 depicts a different construction of the double envelope.

Referring to the drawing:

In figure 1 the balloon/airship is depicted in its inflated state as seen from the outside. The balloon/airship can assume different shapes of the outer envelope 1 other than spherical which is shown here.

In figure 2 the cross- section of the balloon/airship* alon. the plane including its axis, depicts it in the inflated state and shows the relative positions of the ituier envelope 2 and the outer envelope 1 with gas/air space 6 as an integral part of the double envelope.

The points at which the two envelopes are connected together are not shown here for clarity. The purpose of the double envelope is to provide a gas/air space 6 to trap and ϋontain compressed gas/air within it.

The compressed gas/air acts on the outer envelope 1, which pushes baok the atmosphere assuming its normal shape, and is prevented by the inner envelope 2 from entering the vacuum created inside the inner envelope 7 whon the inner envelope 2 expand together with the outer envelope 1.

In figures 3 and 4 two methods of connecting together the two envelopes so that interconnected gas/air passages or spaces 6 are formed into which

£;as/air is to be admitted are depicted.

In figure 5 a different design for the construction of the inner envelope 2 consisting of a helical tube is depicted. The helical tube need not be connected ^' turn by turn to form an airtight envelope.

In figure 6 a double envelope constructed from a helical tube is depicted, however, the turns of the helix have to be so connected as to form a.ι airtight envelope.

In order to inflate the balloon/airship, which, v/hen not in use, has its double envelope flat and folded, gas/air is pumped into gas/air passages 6 via the non-return valve 3 until the balloon/airship becomes inflated and assumes its normal shape, and eventually becomes lighter than air by virtue of the fact that a vacuum is created in the space 7 inside the inner envelope 2 and the weight of the bnlloon/airship becomes lighter than the weight of the volume of the air which has been displaced by the expanding double envelope. At the end of a flight and in order to bring the balloon/airship down to earth, the valve 5 is opened and a sufficient volume of air is admitted into the space 7 inside the inner envelope 2 until the balloon/airship becomes heavier than air and sinks down to earth. In order to deflate the balloon/airship, both the valves 4 and 5 are fully opened, the air trapped in the space 7 inside the inner envelope 2 and the gas/air passages 6 is pushed out into the surrounding atmosphere and finally the balloon/airship is flattened and folded.

The present invention does not possess any of the disadvantages mentioned above and, furthermore, possesses the following advantages;

1) The balloon/airship can be kept airborne for all practical purposes indefinetly.

2) The balloon/airship can be easily inflated by means of, for example, a simple air pump.

3) The balloon/airship can be easily deflated.

4) While the balloon/airship is airborne there will hardly be any need to attend to and maintain its lift.