If you have a balloon ride business would you like to be able to fly a thousand passengers in a single day? How about keeping the balloon flying from sun-up to sun- down and not be concerned about the weather? Sound far-fetched? Not anymore.

In the October issue of Balloon Life Virgin Airship and Balloon Company announced that it is forming a new company, Virgin Aerostations, to do just that. Although Virgin has not, as yet, decided on the equipment it will employ, two companies presently offer systems that may change the face of balloon passenger flying.

In the March issue of Balloon Life the Aérophile 5500 was featured in operation over the France countryside.

In June of this year Lindstrand Balloons, Ltd. entered the market when it delivered its first tethered passenger balloon to Upp & Ner, Stockholm, Sweden.

Upp & Ner, run by Joe Hanson and Casper Anderson, is one of the largest balloon ride operators in Scandinavia. Their fleet of hot air balloons can fly 75 passengers at a time. With the addition of the tethered balloon Upp & Ner are now able to fly revenue rides from dawn till dusk.

Sweden is perhaps the most safety conscious country in the world. Lindstrand Balloons, Ltd. officials told Balloon Life that the certification of the new system for passenger flights was a grueling process involving the most comprehensive testing program any balloon has ever seen.

After completion of the certification process the balloon operation was set up right in downtown Stockholm. From this vantage point the balloon can be seen flying from almost anywhere in the city. What marketing.

The normal height of each ascent is 400 feet. Although the balloon has the capability of rising to 750 feet the spectators do not get to see any more. The lower height allows the balloon to be cycled more times yielding more revenue paying passengers trips.

Upp & Ner has flown as many as 937 people in a single day at 100 krona per ride (about $15).

Although the balloon is rated to carry 30 passengers this tends to get a bit overcrowded. Normally the balloon rises with 20-25 passengers per flight. The balloon is also certified for night flying. Steady red lights and white flashing lights are on the outside of the balloon. Inside four white lights illuminate the entire envelope.

Advertising banners are attached between the envelope and net. The advertising messages are usually sold as a long-term contract. While Lindstrand says that artwork can placed directly on the envelope they recommend using banners for advertising message(s).

Lindstrand reports the balloon is certified for a maximum wind speed of 25 knots but the real wind speed limitation is gusts and turbulence rather than an absolute wind speed number.

Envelope
The balloon envelope is spherical with a volume of 5,750 cubic meters (200,000 cubic feet) and it is designed to retain the appearance of a traditional gas balloon. Although the envelope can be any color the normal color is white since this will result in the least temperature variation from day to night.

The envelope material is a polyester based fabric with a polyurethane coating, followed by two layers of extruded film. The middle film is a polyester which acts as a helium barrier. The outer film is a white opaque tedlar, which is a weather and UV barrier.

The balloon has an internal ballonet. A continuously running fan supplies it with air. By applying these standard airship techniques and an automatic pressure relief valve that keeps the ballonet at a constant pressure, Lindstrand, allows for variation in temperature and pressure which helps the balloon to remain spherical at all times. If the balloon is painted with a dark surface or is operated in a location with extreme changes in temperature a larger volume ballonet would be placed on the balloon.

The balloon is designed to stay inflated at all times, even in high wind conditions. When the wind speed exceeds 25 knots the balloon is moored to the ground by 16 anchor points. These mooring line (which are independent of the normal suspension lines) attach on the envelope equator. With this system the balloon will easily ride out winds of up to 50 knots.

There is also an optional storm protection system which is designed to secure the balloon in wind speeds of at least 80 knots. In this system the 16 round anchor points are fitted with 16 synchronized and remotely controlled electric winch motors. These winch motors all work in unison and can bring down the envelope into contact with the gondola. The top of the gondola is then fitted with a doughnut shaped airbag onto which the envelope is pressed.

A fill hose is permanently attached to the envelope and runs via the net down to the gondola. There is a non-return valve at the envelope's side and the envelope is so designed that helium top ups are only required once a month.

On top of the balloon is an electrically operated helium valve which is rarely used. There is also a pressure sensor that will automatically open the helium valve in the event of an over pressure situation. The valve is normally operated manually from the gondola by an electrical switch and there are indicator lights for the fully closed and open positions. Slightly protruding upwards is anemometer which will show wind speeds on a readout at the gondola instrument panel.

Gondola
The gondola is shaped as an octagon and is manufactured from aircraft quality stainless steel box sections. The exterior panels are made from wicker in order to make the gondola appear like the old traditional balloon baskets. The floor boards are made from marine plywood and are detachable. A safety net is extending around the upper section of the gondola that will prevent exit by people and will prevent any larger objects such as camera being lost over the side. A rain shield can be fitted and is manufactured from clear acrylic panels.

There is one entry and one exit door. Both open inwards and are secured by a twin locking mechanism. If the doors are not properly closed a red light will come on at the operating panel. For ease of transportation the gondola splits into two half semicircle segments.

The operator normally stands in the space between the two doors and thus can easily control the boarding and disembarking process. Behind the operator is a control panel from where all the functions of the balloon are observed and controlled. Control commands to the winch are by radio signals. Should this signal system fail, control will automatically be transferred to the ground station where the ground controller has a hard wired control box. Should all electrical systems fail the ground controller can bring the balloon down by operating hydraulic valves located directly on the winch.

The gondola is designed with a circular walkway that will prevent people bunching up in one corner but more particularly, to give every passenger an unhindered view. While the gondola is certified for 30 people a more practical passenger load of 20-25 provides increased comfort.

The balloon system is designed so that the load from the envelope goes directly to the winch system and the gondola is suspended entirely from the load ring. This means that when the winch brings down the balloon, the gondola is "off-loaded" from its suspension lines. Even if the envelope is oscillating around its tethering point the gondola will remain firmly on the ground.

Additional advertising messages can be carried on the gondola. Or, the gondola and envelope can be color coordinated.

The Winch
The winch is the central element in the entire captive balloon system and it is also the most expensive part of it. While designed specifically for a tethered balloon system, the winch uses components found in similar applications like ski lifts.

The winch cable itself is a 22 millimeter low torque, high tensile wire rope which has an ultimate tensile strength of 48 tons. A swiveling joint is located at the gondola end of the winch cable to prevent cable wind up and immediately above is a load cell that gives the operator an instant read out of the force through the cable.

Should the main power supply fail, back-up power is provided by a diesel engine driving a totally separate hydraulic power pack. There are numerous safety and back- up systems. Even with total hydraulic and electrical failure the emergency braking system will work.

The entire winch package (including the back-up diesel motor) is housed in a 20 foot ISO container. The normal procedure is to dig a hole so that the top of the container will be level with the ground and to position the launch platform immediately above it. It is possible to place the winch motor in a remote location. Total weight of the winch container is 10 tons.

The Net
The net is carrying the entire structural load down from the envelope to the winch cable. It is manufactured from high tenacity monofilament polyester yarn and each element can carry a load of more than a ton. At most there are 192 elements sharing the load in the net.

In addition to the safety advantages of the net it also gives the balloon the look of a traditional gas balloon. Attachment of banners is easier and likewise the net provides secure points for the umbilical cable to the top and the helium fill hose.

The balloon is inflated in the same manner as a traditional gas balloon. During the inflation process a large number of sand bags are hooked to the meshes in the net and gradually shifted downwards until the envelope is fully inflated. The net is u-v treaded and is designed for a five year service life.

Operational Control
The balloon is normally controlled from the gondola. The gondola operator need not have any previous balloon experience and can normally be fully trained in under a week. The control panel is located just below eye level for the operator and displays; wind speed, envelope pressure, ballonet pressure, load cell reading, volts, ambient temperature, and helium temperature. There are warning lights for: fan on, helium valve closed and open, helium pressure, doors open and closed. All electrical functions are protected by circuit breakers.

The power source in the gondola is rechargeable batteries. The whole battery box can be exchanged for a back up one but normally the batteries will last a full day of operations and are recharged overnight.

The night light system consist of red steady lights and white flashing lights on top of the envelope and under the gondola plus four internal halogen lights illuminating the envelope. There are also walk safety lights for the passengers in the gondola.

For more information contact Lindstrand Balloons, Ltd., Maesbury Road, Oswestry, Shropshire, SY10 8ZZ, England. Phone +44 1691 67-17-17, Fax +44 1691 67-11- 22.